U.S. patent application number 14/383710 was filed with the patent office on 2015-01-08 for point of interest database maintenance system.
The applicant listed for this patent is Tom Tom International B.V.. Invention is credited to Richard Hendrik Josephus Jonkman, Antoine Carl van der Laan.
Application Number | 20150012510 14/383710 |
Document ID | / |
Family ID | 46003262 |
Filed Date | 2015-01-08 |
United States Patent
Application |
20150012510 |
Kind Code |
A1 |
van der Laan; Antoine Carl ;
et al. |
January 8, 2015 |
POINT OF INTEREST DATABASE MAINTENANCE SYSTEM
Abstract
A method of processing data at a server (302) for maintenance of
a database (516) of points of interest, such as speed limit
enforcement devices. Each of the devices represented in the
database has at least one attribute and a confidence value
indicative of the accuracy of the at least one attribute associated
therewith. The confidence value is time dependent and varies
according to a pre-defined decay function. A report (500) relating
to an attribute of a speed limit enforcement device is received at
the server (302) from a mobile device (200). The confidence value
associated with the speed limit enforcement device is adjusted in
accordance with the received report, and information relating to
the speed limit enforcement device (520, 522) is selectively
transmitted to the or another mobile device (200) based on the
confidence value.
Inventors: |
van der Laan; Antoine Carl;
(Lelystad, NL) ; Jonkman; Richard Hendrik Josephus;
(Voorhout, NL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Tom Tom International B.V. |
Amsterdam |
|
NL |
|
|
Family ID: |
46003262 |
Appl. No.: |
14/383710 |
Filed: |
March 7, 2013 |
PCT Filed: |
March 7, 2013 |
PCT NO: |
PCT/EP2013/054662 |
371 Date: |
September 8, 2014 |
Current U.S.
Class: |
707/702 |
Current CPC
Class: |
G01C 21/32 20130101;
G08G 1/096741 20130101; G01C 21/3679 20130101; G08G 1/012 20130101;
H04W 4/02 20130101; G08G 1/20 20130101; G01S 7/022 20130101; G06F
16/21 20190101; G08G 1/0141 20130101; G08G 1/096716 20130101; G08G
1/0112 20130101; G06F 16/2365 20190101; G08G 1/096775 20130101 |
Class at
Publication: |
707/702 |
International
Class: |
G06F 17/30 20060101
G06F017/30; G01C 21/32 20060101 G01C021/32 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 7, 2012 |
GB |
GB1204006.9 |
Claims
1. A method of processing data for maintenance of a database of
points of interest (POI), each point of interest represented in the
database having at least one attribute and a time-varying
confidence value indicative of the accuracy of the at least one
attribute associated therewith, the method comprising: transmitting
a request to one or more remote devices to provide confirmation of
an attribute of a point of interest when the confidence value
associated with the point of interest is below a predetermined
threshold; receiving a report relating to the attribute in response
to the transmitted request from at least one of the remote devices;
and adjusting the confidence value associated with the point of
interest in accordance with the received report.
2. The method of claim 1, wherein the confidence value associated
with the point of interest is increased upon receipt of a positive
report indicating the current attribute is correct, and wherein the
confidence value associated with the point interest is decreased
upon receipt of a negative report indicating the current attribute
is incorrect.
3. The method of claim 1, wherein the points of interest are speed
limit enforcement devices.
4. The method of claim 3, wherein the at least one attribute
associated with a speed limit enforcement device comprises one or
more of: an active status of the device; a device type; a location
of the device; a speed limit; a driving direction indicating with
which direction of vehicular travel the device operates; and a time
period during which the device is operational.
5. The method of claim 3, wherein the at least one attribute
associated with a speed limit enforcement device comprises a speed
limit, wherein the speed limit is one of: (i) the actual speed
limit for the road on which the speed limit enforcement device is
located; and (ii) derived from position data received from vehicles
travelling along the road on which the speed limit enforcement
device is located.
6. The method of claim 3, wherein speed limit enforcement devices
are added to and/or modified in the database based on identifying a
change in speed indicative of the presence of a speed limit
enforcement device from position data relating to the position of
at least one vehicle at a plurality of times when travelling along
a route.
7. The method of claim 1, wherein the points of interest comprise
one or more of: parking locations; electric vehicle charging
stations; fuel stations; dynamic advertising locations; and areas
of construction or road works.
8. The method of claim 1, wherein the initial confidence value
associated with a point of interest is based on the source of the
point of interest.
9. The method of claim 1, wherein each point of interest
represented in the database has a plurality of attributes
associated therewith, and the confidence value associated with a
device is a combined confidence value indicative of the accuracy of
each of the attributes.
10. The method of claim 1, wherein the confidence value for a point
of interest is calculated using one or more of: the number of
positive reports received from the remote devices; the number of
negative reports received from the remote devices; the ratio of
positive reports received to negative reports; and the age of each
report.
11. A server system arranged to process data for maintenance of a
database of points of interest (POI), each point of interest
represented in the database having at least one attribute and a
time-varying confidence value indicative of the accuracy of the at
least one attribute associated therewith, the system comprising
memory for storing the database of points of interest and at least
one processor configured to: transmit a request to one or more
remote devices to provide confirmation of an attribute of a point
of interest when the confidence value associated with the point of
interest is below a predetermined threshold; receive a report
relating to the attribute in response to the transmitted request
from at least one of the remote devices; and adjust the confidence
value associated with the point of interest in accordance with the
received report.
12. The system of claim 11, wherein the adjusting the confidence
value comprises increasing the confidence value associated with the
point of interest upon receipt of a positive report indicating the
current attribute is correct, and decreasing the confidence value
associated with the point interest upon receipt of a negative
report indicating the current attribute is incorrect.
13. A non-transitory computer readable medium comprising computer
program code adapted, when said computer program code is run on a
computer, to cause the computer to perform a method of processing
data for maintenance of a database of points of interest (POI),
each point of interest represented in the database having at least
one attribute and a time-varying confidence value indicative of the
accuracy of the at least one attribute associated therewith, the
method comprising: transmitting a request to one or more remote
devices to provide confirmation of an attribute of a point of
interest when the confidence value associated with the point of
interest is below a predetermined threshold; receiving a report
relating to the attribute in response to the transmitted request
from at least one of the remote devices; and adjusting the
confidence value associated with the point of interest in
accordance with the received report.
14. (canceled)
Description
FIELD OF INVENTION
[0001] The present invention, at least in some aspects, relates to
methods and systems of processing data for maintenance of a
database of points of interest, such as speed limit enforcement
devices. Other aspects of the invention relate to the maintenance
of similar data that is temporary or dynamical in nature, such as
the availability of parking spaces or the availability and status
of electric vehicle charging stations.
BACKGROUND TO THE INVENTION
[0002] Portable navigation devices (PNDs) that include GNSS (Global
Navigation Satellite Systems) signal reception and processing
functionality are well known and are widely employed as in-car or
other vehicle navigation systems. Such devices include a GNSS
antenna, such as a GPS antenna, by means of which
satellite-broadcast signals, including location data, can be
received and subsequently processed to determine a current location
of the device. The device may also include electronic gyroscopes
and accelerometers which produce signals that can be processed to
determine the current angular and linear acceleration. The
determined acceleration may then be used in conjunction with
location information derived from the GPS signal to determine the
velocity and relative displacement of the device and thus vehicle
in which it is typically mounted. Such sensors are most commonly
provided in in-vehicle navigation systems, but may also be provided
in the PND itself.
[0003] In recent years, GPS has also been used in systems to warn
drivers of speed traps, enforcement cameras and road hazards, such
as school zones, accident black spots, etc. In such systems, a
device having a GPS antenna and access to a database containing the
location of speed traps, accident black spots, etc is typically
provided in a vehicle. The device is configured to provide warnings
to a driver when the vehicle, using the location information
derived from the GPS signal, is in the vicinity of one of the
locations stored in the database. One such system is described, for
example, in WO 01/55744 A2.
[0004] As will be appreciated by those skilled in the art, one of
the important aspects of such systems is the accuracy and freshness
of the information in the database. For example, it is undesirable
to provide a warning to a user of a speed camera that is no longer
present on the stretch of road, or to incorrectly indicate the
speed limit on a stretch road associated with a speed camera in the
database. In an effort to improve accuracy and freshness of such
data, it is known to collect and utilise reports from drivers and
other users indicating the presence or absence of speed cameras,
and to provide this updated information to other members of the
community in a real-time manner.
[0005] An example of one such system is the Trapster.RTM.
application for mobile devices, and which is described in detail at
www.trapster.com. In this application, all users of the app are
asked to report or validate the status of speed traps, enforcement
cameras and the like. As result of these reports, a digital map can
be shown to a user with various icons and colours representing
different trap types, and in some cases their associated confidence
levels. For example: a green trap icon is displayed to indicate the
presence of an unverified trap; a yellow trap icon is displayed to
indicate that a trap has been verified by another user; a red trap
icon is displayed to indicate that a trap has been verified by
multiple users, and thus has the highest confidence level
associated with it. The application also allows users to report
relatively short-lived hazards, such as: police traps, e.g. an
active sighting of a police speed trap, or a police vehicle
currently observing traffic; construction zones, e.g. road works;
brush fires; road closures; children at play; icy roads; etc. These
hazards are shown to other users, again by means of an icon on the
digital map, but will automatically expire after a certain period
of time following the last positive report from a user confirming
its presence. The particular period of time that elapses before a
hazard is no longer shown to a user varies based on the type of
hazard. For example, a police trap expires after one hour, road
closures after six hours and a construction zone after five
days.
[0006] Despite the improvements in speed trap and enforcement
camera warning systems through the use of so-called active
community feedback, e.g. as described above in relation to the
Trapster.RTM. application, the Applicant believes that there
remains scope for further improvement, and in particular with
respect to the accuracy and freshness of data in the associated
database.
SUMMARY OF THE INVENTION
[0007] In accordance with a first aspect of the invention there is
provided a method of processing data for maintenance of a database
of points of interest (POI), each point of interest represented in
the database having at least one attribute and a confidence value
indicative of the accuracy of the at least one attribute associated
therewith, wherein the confidence value is time dependent and
varies according to a predefined function, the method comprising:
[0008] receiving a report relating to an attribute of a point of
interest; [0009] adjusting the confidence value associated with the
point of interest in accordance with the received report; and
[0010] transmitting information relating to the point of interest
to a remote device based on the confidence value associated with
the point of interest.
[0011] Further, and in accordance with another aspect of the
invention there is provided a system, optionally a server system,
arranged to process data for maintenance of a database of points of
interest (POI), each point of interest represented in the database
having at least one attribute and a confidence value indicative of
the accuracy of the at least one attribute associated therewith,
wherein the confidence value is time dependent and varies according
to a predefined function, the system comprising: [0012]
communication means for receiving a report relating to an attribute
of a point of interest; and [0013] means for adjusting the
confidence value associated with the point of interest in
accordance with the received report; [0014] wherein the
communication means is further arranged to transmit information
relating to the point of interest to a remote device based on the
confidence value associated with the point of interest.
[0015] The present invention in this further aspect may include any
or all of the features described in relation to the first aspect of
the invention, and vice versa, to the extent that they are not
mutually inconsistent. Thus, if not explicitly stated herein, the
system of the present invention may comprise means for carrying out
any of the steps of the method described.
[0016] The means for carrying out any of the steps of the method
may comprise a set of one or more processors configured, e.g.
programmed, for doing so. A given step may be carried out using the
same or a different set of processors to any other step. Any given
step may be carried out using a combination of sets of
processors.
[0017] The present invention relates to the creation and
maintenance of a database of points of interest (POI). The term
"point of interest" takes it usual meaning within the art and thus
refers to a permanent or temporary object at a particular location,
e.g. point or region, that is of interest to a person or company. A
POI may therefore be a building, such as a shop, tourist attraction
or the like, or an area such as park. Similarly, a POI may be an
object such as a speed limit enforcement device, e.g. a fixed speed
camera (either individual cameras or as part of average speed
zones), mobile speed camera, etc, or an dynamic advertising space
(capable of displaying data sent to it from a remote location).
[0018] Each POI represented in the database has one or more
associated attributes, preferably a plurality of such attributes.
For example, in a preferred embodiment of the invention where the
POI database is a database of speed limit enforcement devices,
these attributes can include the type of speed camera, the location
of the camera, the speed limit associated with the camera, and the
driving direction associated with the camera. Each POI also has at
least one associated confidence value which is indicative of the
accuracy of one, some or all of the associated attributes.
[0019] The database, which is typically stored on a server or is
accessible by a server, is maintained by receiving reports from
various sources, such as mobile devices, data obtained from web
crawlers, etc, containing information indicating whether the
current attributes for a POI are correct or not. The system of the
present invention therefore comprises communication means for
transmitting data to, and receiving data from, a plurality of
remote devices. These reports are used to adjust, e.g. increase or
decrease, a confidence value associated with a POI in the database.
The confidence value, as described below, ages according to a
predefined function, such that the confidence value changes over
time (even without reports being received for the POI).
[0020] Data relating to a POI is transmitted to one or more remote
devices (e.g. devices, such as mobile devices, that are spatially
remote from the database) in dependence on the confidence value for
the POI. For example, when the confidence value for a particular
POI falls below a predetermined threshold, then updated data
relating to the POI may no longer be transmitted to remote devices.
The transmitted data, as will be discussed in more detail below, is
preferably indicative of least one of the confidence value or an
attribute of the POI, and can be used, for example when the POI is
a speed limit enforcement device, by the remote device to determine
whether to provide alerts or warnings to a driver or not.
[0021] The use of confidence values that age according to a
predefined function, and which can preferably also be adjusted
positively or negatively following received reports, e.g. from
mobile devices, moderators or third party data, enables a greater
degree of control when fusing data from numerous sources to allow
for an increased level of freshness and accuracy. For example, in
the known arrangements described above, map data in the database is
always present for a certain period of time following the last
report from a user supporting the presence of the device. In
contrast, in the present invention, a POI such as a speed limit
enforcement device can rapidly be made inactive, i.e. such that no
alerts or warnings are provided to a user, thereby reducing the
number of false positives often experienced with such systems.
[0022] The method of the present invention relates to the
maintenance of a database of points of interest. The invention will
be described in the following passages in relation to a database of
speed limit enforcement devices. It will be appreciated, however,
that the methods of the invention are equally applicable to any
type of point of interest, and are not limited only to speed limit
enforcement devices. Accordingly, in the following, the term "speed
limit enforcement device" can be replaced by the term "point of
interest", unless the context requires otherwise.
[0023] The speed limit enforcement devices in the database can
comprise any type of device that can be used to enforce the speed
limit assigned to a road, such as a fixed devices, e.g. speed
cameras, red lights cameras, and mobile devices, such as those
contained in parked vehicles or held by law enforcement
officers.
[0024] The method may be implemented by a processing resource of a
server, e.g. with the database of speed limit enforcement devices
being stored at the sever. Alternatively, or additionally if there
are multiple databases, e.g. of differing levels of quality,
richness (amount of detail), etc, one or more of the databases may
be stored remotely from the server, but be accessible by the
processing resource of the server via suitable communications link.
The link may be a wireless link or a wired link or may comprise
combinations thereof.
[0025] Each speed limit enforcement device in the database
maintained according to the present invention has at least one
attribute associated with it, together with a confidence value
indicative of the accuracy of the least one attribute. In some
embodiments, there may only be a single attribute associated with a
speed limit enforcement device, although preferably at least some,
and typically all, of the devices have a plurality of associated
attributes.
[0026] The at least one attribute associated with a speed limit
enforcement device can be one or more of: a device type; a location
of the device; a speed limit; a driving direction indicating with
which direction of vehicular travel the device operates (or in
other words with which side of the road the device is positioned to
monitor); a time period during which the device is operational; and
an indication of the number of reports submitted by users in
respect of the device.
[0027] The device type attribute may indicate that the device is
any suitable and desired form of speed limit enforcement device.
For example, the device type attribute may indicate that the device
is a fixed speed camera, or that the device is a mobile speed
camera. The device type attribute may also indicate whether the
camera is used in conjunction with one or more other cameras as
part of an average speed trap (i.e. where a vehicle's speed is
monitored over a relatively long distance, such as a number of
kilometres, to ensure that the average speed of the vehicle does
not exceed the legal speed limit). As will be discussed in more
detail below, the type of the speed limit enforcement device may be
used to determine the confidence value decay profile to be used
with a device.
[0028] The device location attribute indicates the geographic
location of the speed limit enforcement device. The attribute may
represent a point location, e.g. as a longitude and latitude pair,
or with reference to a road segment in an electronic map. For
example, the location could indicate that the speed limit
enforcement device is a certain distance along a road segment of an
electronic map, and may also indicate on which side of the road
segment the device is located. The location reference could be made
with respect to a particular electronic map, or the location
reference could be map-agonistic by being generated using a dynamic
location referencing method, such as AGORA-C or OpenLR.RTM.. The
device location attribute may alternatively represent an area,
instead of a point, such as a geographic area or a portion of a
road segment. Such an area may be used, for example, where the
speed limit enforcement device is part of an average speed trap;
the area may therefore represent the road between the start and end
of the average speed zone. An area could also be used when, for
example, legislation within a territory does not permit a driver to
know the exact location of a speed limit enforcement device, but
only a zone having a device located therein.
[0029] The speed limit attribute indicates a speed limit associated
with an enforcement device which may be used by a mobile device to
provide suitable warnings to a user. The attribute may be the
actual speed limit for the road on which the enforcement device is
located, e.g. having been received from third party or Government
data, or after having been confirmed from user reports or mobile
mapping data. Alternatively, the speed limit attribute may be
derived from position data received from vehicles travelling along
the road segment on which the device is located. For example, the
position data can be processed to determine an average speed for
the road segment, and the speed limit attribute for the device is
set, at least initially, as the determined average speed.
[0030] A speed limit enforcement device may have a plurality of
speed limit attributes, e.g. if the speed limit for a road varies
throughout the day, such as having a different value during hours
of peak traffic; or if the speed limit for a road varies throughout
the week, such as having a different value on the weekend.
Similarly, a speed limit enforcement device may also have an
associated temporal attribute that indicates times at which the
device is operational. This may be beneficial in areas where
construction work is taking place, and speed cameras are only
active during periods when working is taking place.
[0031] The driving direction attribute may indicate that the speed
limit enforcement device is only applicable when a driver is
travelling in one direction along a road. Alternatively, the
attribute may indicate that the device is applicable to vehicles
travelling in both directions along a road. The absence of a
driving direction attribute may similarly indicate that the device
operates in both directions of travel.
[0032] The attribute providing an indication as to the number of
reports submitted in respect of a device can take any form as
desired. For example, the attribute may indicate one or more of:
the total number of reports submitted for a device; the number of
reports submitted in support of a device; and the number of reports
submitted requesting deletion of a device. The attribute may be
indicative of the number of reports received over the entire
lifetime of a device in the database, or over a particular time
period. For example, it is therefore envisaged that each received
report may be binned into one of a plurality of temporal periods,
such as weekly, daily, hourly, etc.
[0033] As will be appreciated, the database of speed limit
enforcement devices in the present invention is continually being
updated with new devices, or with changes to devices already
existing in the database, based at least on reports from users.
Speed limit enforcement devices can additionally be entered and/or
modified in the database in a number of other possible ways.
[0034] For example, third party data could be used to supply the
initial locations and attributes of speed limit enforcement
devices. Moderators could also manually add speed limit enforcement
devices to, or modify devices in, the database, e.g. after
validating a user report indicating the presence of a device, or
after identifying the presence of a device from aerial, satellite
or mobile mapping vehicle images.
[0035] In addition, or alternatively, the presence of speed cameras
could be inferred from changes in the vehicle speed.
[0036] For example, and as described in WO 2011/023719 A1, the
entire contents of which is incorporated herein by reference,
mobile devices carried by vehicles can detect a particular speed
profile, such as a reduction in speed, followed by a substantially
constant speed at or below the speed limit for the road,
potentially followed by an increase in speed. A report may then be
sent from the mobile device to a server indicating the location of
the vehicle at the time the characteristic speed change is
detected. The report could also include information relating to
other attributes of a potential speed limit enforcement device,
e.g. the direction of travel of the vehicle, the speed of the
vehicle during the substantially constant speed phase of the
profile, etc. Such reports may be used to add speed limit
enforcement devices to, or modify devices in, the database of the
present invention.
[0037] It is also envisaged that position data relating to the
position of a vehicle at different times when travelling along a
route, and which is received at a server, can be used to infer the
presence of a speed limit enforcement device. Typically, such
position data is obtained from a plurality of different vehicles.
The position data received from multiple mobile devices travelling
along the same navigable segment can be processed to infer the
position of a speed limit enforcement device, e.g. by identifying
changes in vehicle speed characteristic of a speed limit
enforcement device. The determined speed limit enforcement device
may then be added to the database, together with an associated
confidence value. The associated confidence value may be such that
warnings or alerts concerning a speed limit enforcement device
inferred in this manner are not provided to drivers until at least
one driver has confirmed the presence of the device. Further
details concerning the calculation of confidence values, and how
the confidence value effects the way in which a speed limit
enforcement device is handled by the system, are provided below.
One or more attributes associated with a speed limit enforcement
device, in addition to a location, can also be inferred from the
position data, e.g. a speed limit, driving direction, etc.
[0038] In the present invention, a confidence value is associated
with each speed limit enforcement device in the database. The
confidence value is representative of how certain it is that the
device is actually present in reality and/or how certain it is that
the attributes associated with the device are correct.
[0039] As will be appreciated, a device may have a single
associated confidence value, or alternatively it may have a
plurality of confidence values, e.g. one for each of the attributes
associated with a device. If a device has a single associated
confidence value, then this value may be indicative of the accuracy
of a single attribute, but in a preferred embodiment it may
represent a combined confidence value indicative of the accuracy of
a plurality, and preferably each, of the attributes associated with
the device.
[0040] The confidence value may take any suitable form, but
preferably at any point in time it is a value between a minimum and
maximum value, e.g. between 0 and 1, or between 0% and 100%. The
minimum value indicating that there is no confidence in the
attribute associated with the confidence value. Conversely, the
maximum value indicating that there is no doubt as to the accuracy
of the attribute associated with the confidence value.
[0041] In aspects of the present invention, the confidence value is
not only time-dependent, i.e. varying in time due to the receipt of
reports from mobile devices (and users thereof) either supporting,
requesting changes to, or deletion of, a device in the database,
but it also is arranged to vary according to a predefined function.
In other words, when a speed limit enforcement device is added in
the database, i.e. time t=0, it is assigned an initial confidence
value C(t=0)=C.sub.0. This initial confidence value then changes
over time in dependence on a function f(t), such that at a later
point in time T, assuming no reports, either positive or negative,
have been received for a device, then the device will have an
effective confidence value:
C.sub.effective(t=T)=f(T)C.sub.0
Typically, however, reports will be received in respect of a
device, and thus the confidence value for a device at a point in
time T' will also be based, at least, on any received reports.
Accordingly, the effective confidence value for a device will
typically be:
C.sub.effective(t=T')=f(T')C(T')
[0042] The predefined function can be of any suitable and desired
form. For example, the predefined function can be a growth
function, i.e. causing the confidence value to increase over time.
In preferred embodiments of the invention, however, and for example
in embodiments relating to speed limit enforcement devices, the
predefined function is a decay function, i.e. causing the
confidence value to decrease (or age) over time.
[0043] As will be appreciated, the term "confidence value" used
herein will, unless the context requires otherwise, refer to the
actual confidence value associated with a speed limit enforcement
device in the database at a particular point in time. Accordingly,
in embodiments where the confidence value changes according to a
predefined function, e.g. decay or growth profile, the term
"confidence value" will refer to the effective confidence value,
i.e. wherein the confidence value determined as a result of user
reports (and an initial confidence value) is further modified
according to the decay or growth profile.
[0044] The initial confidence value for a device in the database
can be determined in any suitable and desired manner. In preferred
embodiment, however, the initial confidence value will be based on
the manner in which the speed limit enforcement device is added to
the database, or in other words the source of the speed limit
enforcement device.
[0045] For example, in some embodiments, the initial confidence
value may be fixed value, e.g. when the device is added based on
third party data or by a moderator. In such circumstances, the
initial confidence value will typically be relatively high, e.g. at
or close to the maximum value, as the information obtained from
these sources is typically of a high quality. A different fixed
value may be used for each source, e.g. a first initial confidence
value may be used when the data is obtained from a first company,
whilst a second initial confidence value may be used when the data
is obtained from a second different company.
[0046] In other embodiments, for example when the presence of a
speed limit enforcement device is inferred from detected changes in
vehicular speed, e.g. from the processing of received position
data, the initial confidence value may be based on the received
position data. Typically, the initial confidence value associated
with devices added to the database from such sources will be
relatively low.
[0047] In yet other embodiments, for example where the presence of
a speed limit enforcement device is determined following the
receipt of a report from a mobile device, the initial confidence
value may be based on a trust level of the user who submitted the
report. For example, a relatively high initial confidence value may
be associated with a speed limit enforcement device if the user has
a history of submitting high quality, accurate reports. Conversely,
a relatively low confidence value may be associated with a device
if the user has a history of submitting poor quality, inaccurate
reports.
[0048] The predefined function, e.g. decay function, that is used
to age the confidence value associated with a speed limit
enforcement device in the database can also be of any suitable and
desired form. For example, the decay function may be at least one
of: a linear function, an exponential function, and a polynomial
(e.g. quadratic, cubic, etc) function.
[0049] As will be appreciated, the confidence value of the present
invention is preferably arranged to vary between a maximum and
minimum value and may be at one or more intermediate values
therebetween. Accordingly, a step (or Heaviside) function should
not be considered to be a growth or decay function within the scope
of the present invention.
[0050] The same function, e.g. decay function, may be used for all
speed limit enforcement devices in the database, such that
confidence in all devices decays at the same rate. Alternatively,
in other embodiments, different functions may be used with
different speed limit enforcement devices in the database. For
example, a function may be selected for use with a device based on
at least one attribute associated with the device, preferably the
device type attribute. For example, a first decay function may be
used with fixed speed limit enforcement devices, and a second decay
function used with mobile speed limit enforcement devices. In such
embodiments, the first decay function preferably decays slower than
the second decay function, such that fixed devices should remain
active in the system longer than mobile devices.
[0051] As will be appreciated, the server system of the present
invention communicates with one or more remote devices to ensure
that the data in the speed limit enforcement device database is
accurate and up to date. The remote devices, i.e. devices that are
spatially remote from the server system, can be of any suitable
form. For example, the information from the server system may be
sent to fixed location devices, e.g. home computers and the like.
In a preferred embodiment, however, the remote devices are mobile
devices that are preferably of a form where they can be carried or
transported in a vehicle. The mobile devices may be portable
devices, e.g. capable of being handheld, and which, for example,
may be removably mounted within a vehicle. Alternatively, or
additionally, the mobile devices may be in-vehicle systems, i.e.
devices that are permanently mounted within vehicles.
[0052] As will be appreciated, the mobile devices are preferably
capable of determining the current position of the device, and thus
preferably comprise location determining means. The location
determining means could be of any type. For example, a mobile
device could comprise means for accessing and receiving information
from WiFi access points or cellular communication networks, and
using this information to determine its location. In preferred
embodiments, however, a mobile device comprises a global navigation
satellite systems (GNSS) receiver, such as a GPS receiver, for
receiving satellite signals indicating the position of the receiver
at a particular point in time, and which preferably receives
updated position information at regular intervals.
[0053] The mobile devices may also include means for determining
the relative displacement of the vehicle in which the device is
carried, thereby allowing, for example, the speed and driving
direction of the vehicle at any point in time to be determined. The
means could comprise one or more electronic gyroscopes or
accelerometers in the device, or the device could have access to
such sensors in the vehicle itself, e.g. using the vehicle CAN
bus.
[0054] Accordingly, in preferred embodiments, the mobile devices
that are utilised in the present invention comprise navigation
apparatus, such as portable navigation devices (PNDs) that can be
removably mounted within a vehicle or in-vehicle navigation
systems, and which preferably include GNSS signal reception and
processing functionality. It will be appreciated, however, that the
mobile devices may also comprise mobile telephones, PDAs, tablet
computers or the like running suitable software programs.
[0055] The mobile devices also comprise communication means for
transmitting and receiving information from the system, e.g.
server, of the present invention. The information, as will be
discussed in more detail below, may comprise reports indicating new
speed limit enforcement devices or errors associated with speed
limit enforcement devices already in the database. The information
may comprise data indicative the confidence value, or effective
confidence value, associated with a speed limit enforcement, and/or
data indicative of an attribute associated with a speed limit
enforcement device. The communication means could be of any type.
For example, the devices may comprise one or more physical
connector interfaces by means of which power and/or data signals
can be transmitted to and received from the device. In preferred
embodiments, however, the communication means comprises one or more
wireless transmitters/receivers to allow communication over
cellular telecommunications and other signal and data networks, for
example WiFI, Wi-Max, GSM and the like.
[0056] As will be appreciated, the mobile devices also comprise
means for alerting a user to the presence of a speed limit
enforcement device, and optionally providing additional information
relating to the device, such as the speed limit. The alert could be
one or more of a visual alert, an audio alert and a haptic
alert.
[0057] In embodiments of the present invention, reports are
received from mobile devices containing information indicating the
presence of a new speed limit enforcement device and/or whether the
current attributes for a speed limit enforcement device are correct
or not. These reports will typically be generated in response to a
user input, e.g. by the user inputting information on a mobile
device indicating a new speed limit enforcement device or an error
in an already exiting device. It is also envisaged, however, that
reports could be automatically generated, partially or fully, by
the mobile device.
[0058] For example, in a preferred embodiment, a user may input on
the mobile device the presence of a speed limit enforcement device,
such as by pressing a hard button or soft (or virtual) key on the
device. The user may additionally input one or more attributes
associated with the speed limit enforcement device. Alternatively,
or additionally, these other attributes may be automatically
generated by the device, such as by setting the current vehicle
location, speed and/or driving direction as the location, speed
limit and driving direction attributes, respectively, for the
device.
[0059] In other embodiments, and if, for example, the mobile device
receives images of a vehicle's surroundings from a camera feed,
image recognition techniques could be used to automatically
determine the presence of speed limit enforcement devices on the
images received from the camera feed.
[0060] Each received report preferably includes at least one
modified or new attribute value associated with a speed limit
enforcement device. Each report may include only a single attribute
value for a device, or it may include a plurality of attribute
values. As discussed above, one or more of the attribute values may
be input by a user or be automatically generated by the mobile
device.
[0061] Reports may be determined to relate to the same speed limit
enforcement device using any suitable method. For example, if the
location of the speed limit enforcement device in the report is
within a predetermined distance of the location of a speed limit
enforcement device already existing in the database, then the
reports can be said to relate to the same device.
[0062] The received reports are preferably used to modify the
attributes associated with a speed limit enforcement device and/or
adjust, e.g. increase or decrease, as necessary, the confidence
value of the speed limit enforcement device referred to the
report.
[0063] The attributes associated with a speed limit enforcement
device may be modified in any suitable and desired manner. For
example, the location of the device may be modified so as to be the
average of the current location and the location indicated in the
report. Similarly, the speed limit of the device may be modified so
as to be the average of the current speed limit and the speed limit
indicated in the report. The average may be a weighted average,
e.g. based on a trust level of the source of the report, such as
the user that submitted the report.
[0064] The confidence value for a speed limit enforcement device at
a particular point in time, before the impact of aging according to
the predetermined function is taken into account, is, at least in
part, dependent on reports received from mobile devices (and thus
users) relating to the particular speed limit enforcement device.
The confidence value can be calculated in any suitable manner, but
preferably it will utilise one of more of the following: the number
of positive reports received (where a positive report is one that
supports the continued existence of a speed limit enforcement
device in the system); the number of negative reports received
(where a negative report is one that supports the removal of a
speed limit enforcement device in the system); the ratio of
positive reports received to negative reports; the age of a report
(e.g. newer reports are viewed as being more relevant than older
reports); and the confidence value associated with each individual
attribute, e.g. a location confidence, a speed limit confidence
and/or a type confidence.
[0065] The confidence value associated with a speed limit
enforcement device in the database can be used in a number of
advantageous ways in embodiments of the present invention. In
particular, in the present invention, information relating to a
speed limit enforcement device is transmitted to one or more remote
devices based on the confidence value for the speed limit
enforcement device in the database.
[0066] The information relating to a speed limit enforcement device
may be of any suitable and desired form. For example, the
information may be indicative of an attribute of a speed limit
enforcement device, and may include: an attribute or attributes of
a new device recently added to the database; or a recently changed
attribute relating to speed limit enforcement device already
existing in the database. Updated information relating to speed
limit enforcement device can therefore be provided to users.
[0067] The information may, alternatively or additionally, be
indicative of the confidence value of a speed limit enforcement
device. For example, in a preferred embodiment, the confidence
value associated with a speed limit enforcement device can be used
as an indication that the device should be active in the database,
i.e. the device continues to exist in reality, or inactive, i.e.
the device no longer exists in reality, and thus whether a mobile
device should provide warnings or alerts to a driver in relation to
the speed limit enforcement device in question. In other words,
when the confidence value of a speed limit enforcement device in
the database falls below a predetermined threshold, then it is
assumed that the device is no longer present in the real world, and
drivers are no longer informed about the device. This therefore
significantly reduces the number of false positive warnings that
are commonly provided to drivers in known systems.
[0068] Thus, in embodiments of the invention, the method comprises
transmitting an indication to one or more mobile devices that
alerts relating to the presence of a speed limit enforcement device
should no longer be issued to a user. The indication may be
transmitted when the confidence value associated with the speed
limit enforcement device is below a predetermined threshold.
Alternatively, the indication may be transmitted each time there is
a change in the confidence value of a speed limit enforcement
device due to a received report.
[0069] The indication sent to the one or more mobile devices can be
of any suitable and desired form. For example, in embodiments where
the indication is transmitted when the confidence value falls below
a threshold value, the indication could be a list of one or more
devices that have changed from being active to inactive, or vice
versa. Alternatively, if the indication is sent whenever there is a
change in confidence value due to a received report, the server
system may transmit an updated confidence value for an enforcement
device, and the determination as to whether a speed limit
enforcement device is active or inactive is made on the mobile
device itself. In other embodiments, rather than sending an updated
confidence value, the server system may transmit a time when alerts
for a speed limit enforcement device are no longer to be issued;
the time being based on when the current confidence value for the
speed limit enforcement is due to fall below the threshold level
according to the predetermined decay function.
[0070] As will be appreciated, when a device is made inactive in
the database, it may actually be deleted from the database.
Alternatively, the device may remain in the database, e.g. for
future reference or to be made active again at a later date. For
example, a mobile speed camera may be intermittently used for at
the same location, and thus may be active or inactive at different
times.
[0071] The information transmitted to one or more mobile devices
may, alternatively or additionally, be a request to provide
confirmation of an attribute of a speed limit enforcement device,
or data that causes such a request to be generated on the mobile
device. The attribute may include the presence of the speed limit
enforcement, or it may relate to information about the device
itself, such as the associated speed limit or driving direction. By
actively requesting feedback from users to confirm information
about, and in particular the presence of, a speed limit enforcement
device, the confidence in a device can be quickly increased to a
high level or decreased to a low level (such that the device can be
made inactive in the database).
[0072] Thus, in embodiments of the invention, the method comprises
transmitting a request to one or more mobile devices to provide
confirmation of an attribute of a speed limit enforcement device
when the confidence value associated with the speed limit
enforcement device is below a predetermined threshold. A report is
preferably received from one or more of the remote, e.g. mobile,
devices in response to the request, and the confidence value
associated with the speed limit enforcement device adjusted
accordingly.
[0073] In other embodiments, the method comprises transmitting data
to one or more mobile devices each time there is a change in the
confidence value of a speed limit enforcement device due to a
received report, the data causing a request to be generated on the
mobile device to provide confirmation of an attribute of a speed
limit enforcement device. The data may be a time when the request
is to be provided to a user; the time being based on when the
current confidence value for the speed limit enforcement is due to
fall below the threshold level according to the predetermined decay
function.
[0074] It is believed that the use of confidence values associated
with points of interest, such as speed limit enforcement devices,
to request feedback from users may be new and advantageous in its
own right.
[0075] Thus, in accordance with a further aspect of the invention
there is provided a method of processing data for maintenance of a
database of points of interest (POI), each point of interest
represented in the database having at least one attribute and a
time-varying confidence value indicative of the accuracy of the at
least one attribute associated therewith, the method comprising:
[0076] transmitting a request to one or more remote devices to
provide confirmation of an attribute of a point of interest when
the confidence value associated with the point of interest is below
a predetermined threshold; [0077] receiving a report relating to
the attribute in response to the transmitted request; and [0078]
adjusting the confidence value associated with the point of
interest in accordance with the received report.
[0079] In accordance with another aspect of the invention there is
provided a system, optionally a server system, arranged to process
data for maintenance of a database of points of interest (POI),
each point of interest represented in the database having at least
one attribute and a time-varying confidence value indicative of the
accuracy of the at least one attribute associated therewith, the
system comprising: [0080] communication means for transmitting a
request to one or more remote devices to provide confirmation of an
attribute of a point of interest when the confidence value
associated with the point of interest is below a predetermined
threshold; and [0081] means for adjusting the confidence value
associated with the point of interest in accordance with a report
received by the communication means in response to the transmitted
request.
[0082] The present invention in any of these further aspects may
include any or all of the preferred and optional features described
herein as appropriate. For example, the points of interest in the
database may be speed limit enforcement devices, and the attribute
of the speed limit enforcement device can be any one or more of:
the presence of the device; the device type; the location of the
device; the speed limit associated with the device; the driving
direction indicating with which direction of vehicular travel the
device operates; and the time period during which the device is
operational. In embodiments, the confidence value may also vary
according to a predefined growth or decay function, such as a
linear, exponential or polynomial function.
[0083] The means for carrying out any of the steps of the method
may comprise a set of one or more processors configured, e.g.
programmed, for doing so. A given step may be carried out using the
same or a different set of processors to any other step. Any given
step may be carried out using a combination of sets of
processors.
[0084] In preferred embodiments of the invention, the system uses
at least two predetermined thresholds with regard to the confidence
value.
[0085] For example, in one embodiment, when the confidence value
for a speed limit enforcement device falls below a first
predetermined threshold, then a request is sent to one or more
remote, e.g. mobile, devices to provide confirmation of an
attribute of the speed limit enforcement device. Further, when the
confidence value for a speed limit enforcement device falls below a
second predetermined threshold, the second threshold being less
than the first threshold, then an indication is transmitted to one
or more remote, e.g. mobile, devices that alerts relating to the
presence of a speed limit enforcement device should no longer be
issued to a user.
[0086] In another embodiment, each time the confidence value for a
speed limit enforcement device changes due to a received report, a
plurality of time values can be sent to one or more remote, e.g.
mobile, devices. The plurality of time values comprise a first time
value indicating the time at which the confidence value of the
speed limit enforcement device will fall below a first
predetermined threshold (based on the predetermined decay
function). At the time indicated by the first time value, a request
will be generated and provided to a user on the mobile device
asking for confirmation of an attribute of the speed limit
enforcement device. The plurality of time values also comprise a
second time value indicating the time at which the confidence value
of the speed limit enforcement device will fall below a second
predetermined threshold (based on the predetermined decay
function), the second threshold being less than the first
threshold. At the time indicated by the second time value, alerts
relating to the presence of the speed limit enforcement device will
no longer be issued to the user on the mobile device. The plurality
of time values may also comprise a third time value indicating the
time at which the confidence value of the speed limit enforcement
device will fall to zero or another suitable value (based on the
predetermined decay function). At the time indicated by the third
time value, the speed limit enforcement device will be
[0087] The above embodiments are described with reference to
confidence values that age according to a predetermined decay
function; thus actions are said to be taken when the confidence
value falls below certain threshold levels. As will be appreciated,
however, in embodiments where the confidence value varies according
to a predetermined growth function, actions will in contrast be
taken when the confidence value rises above certain threshold
levels.
[0088] As will be appreciated from the above, information relating
to speed limit enforcement devices is regularly transmitted to one
or more remote, e.g. mobile, devices. This information may be
transmitted to all mobile devices, whether the information will be
of use to them in the near future or not. Preferably, however, the
information relating to a speed limit enforcement device is
transmitted only to devices that are, or will be, in the vicinity
of the device. This therefore reduces the amount of information
that needs to be transmitted to mobile devices.
[0089] Thus, for example, one or more mobile devices may provide
the system, e.g. server, with location information relating to at
least one of a current or future location. For example, a mobile
device may provide a planned route of travel to the server. This
location information can then be used by the system to select the
mobile devices that should receive, preferably over the air (OTA)
using wireless communication means, database changes and requests
to confirm an attribute of speed limit enforcement devices.
Accordingly, in embodiments, information relating to new and
changed speed limit enforcement devices may be transmitted only to
mobile devices that are or will be passing the locations associated
with speed limit enforcement devices. Similarly, attribute
confirmation requests may be transmitted only to mobile devices
that have recently passed or will pass the particular speed limit
enforcement device in question.
[0090] As will be appreciated, the present invention extends to a
mobile device, optionally a navigation device, configured to
operate with the system as described above.
[0091] Similarly, the present invention also extends to a database
of points of interest (POI), such as speed limit enforcement
devices, generated and/or maintained using the above described
method of the present invention.
[0092] It will also be appreciated by those skilled in the art that
all of the described aspects and embodiments of the present
invention can, and preferably do, include, as appropriate, any one
or more or all of the preferred and optional features described
herein.
[0093] The methods in accordance with the present invention may be
implemented at least partially using software. It will thus be seen
that, when viewed from further aspects, the present invention
extends to a computer program product comprising computer readable
instructions adapted to carry out any or all of the methods
described herein when executed on suitable data processing means,
such as a server system.
[0094] The invention also extends to a computer software carrier
comprising such software. Such a software carrier could be a
physical (or non-transitory) storage medium or could be a signal
such as an electronic signal over wires, an optical signal or a
radio signal such as to a satellite or the like.
[0095] Although the present invention has been described in
relation to maintaining a database of points of interest, and in
particular speed limit enforcement devices, it will be appreciated
that similar methods could be used with any information and/or map
data that may, for example, be temporary in nature and/or requiring
regular updates from users; in other words dynamic data. For
example, it is envisaged that the methods of the present invention
could be used to maintain a database of: parking spaces and/or
parking areas, and the availability thereof; areas of construction
or road works; electric vehicle charging stations, and the
availability thereof; etc.
[0096] Thus, for example, in embodiments relating to parking spaces
and/or parking areas, which comprise a plurality of parking spaces,
the at least one attribute associated with each parking space
and/or area can comprise one or more of: a location of the space
and/or area; an availability of the space and/or area; and times
when the space and/or area are available for use.
[0097] Similarly, in embodiments relating to electric vehicle
charging stations, the at least one attribute associated with each
charging station can comprise one or more of: a location of the
charging station; an availability of the charging station; a type
of the charging station (e.g. quick charge, slow charge, etc); and
times when the charging station can be used.
[0098] It is also envisaged that the methods of the present
invention can be used in dynamic signage, i.e. electronic displays
that show information, such as television programs, menus,
advertising, etc. In such embodiments, certain information could be
displayed for longer periods of time based on a number of positive
votes received from the general public.
[0099] The present invention in any of these further aspects may
include any or all of the preferred and optional features described
herein as appropriate.
[0100] The means for carrying out any of the steps of the method
may comprise a set of one or more processors configured, e.g.
programmed, for doing so. A given step may be carried out using the
same or a different set of processors to any other step. Any given
step may be carried out using a combination of sets of
processors.
[0101] Advantages of these embodiments are set out hereafter, and
further details and features of each of these embodiments are
defined in the accompanying dependent claims and elsewhere in the
following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0102] Various aspects of the teachings of the present invention,
and arrangements embodying those teachings, will hereafter be
described by way of illustrative example with reference to the
accompanying drawings, in which:
[0103] FIG. 1 is a schematic illustration of a Global Positioning
System (GPS);
[0104] FIG. 2 is a schematic illustration of electronic components
arranged to provide a navigation device;
[0105] FIG. 3 is a schematic illustration of the manner in which a
navigation device may receive information over a wireless
communication channel;
[0106] FIG. 4 is a perspective view of a navigation device;
[0107] FIG. 5 shows how the confidence value for fixed and mobile
speed cameras ages over time when no user reports are received;
and
[0108] FIG. 6 shows how the confidence value for a speed camera
varies over time when user reports are received;
[0109] FIG. 7 is a schematic representation of an exemplary server
system in accordance with the present invention.
[0110] Like reference numerals are used for the like features
throughout the drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0111] The present invention is directed to a method and system for
processing data to maintain a database of speed limit enforcement
devices. In order to keep the data in the database accurate and up
to date, the system utilises information in the form of reports
received from a plurality of mobile devices. In other words, the
system relies on a community of users to continually supply
information on new speed limit enforcement devices not already in
the database, and to validate the details associated with the
devices already in the database.
[0112] The mobile devices can be of any suitable form, but in
illustrative embodiments are navigation apparatus, such as portable
navigation devices (PNDs). Preferred embodiments of the present
invention will now be described with particular reference to a PND.
It should be remembered, however, that the teachings of the present
invention are not limited to PNDs but are instead universally
applicable to any type of processing device that is configured to
warn or alert drivers when they are approaching speed limit
enforcement devices using a local and/or remote database listing
such devices. It follows therefore that in the context of the
present invention, the mobile devices could be a PND, a navigation
device built into a vehicle, or indeed a computing resource (such
as a desktop, portable personal computer (PC), tablet computer,
mobile telephone or portable digital assistant (PDA)).
[0113] FIG. 1 illustrates an example view of Global Positioning
System (GPS), usable by navigation devices. Such systems are known
and are used for a variety of purposes. In general, GPS is a
satellite-radio based navigation system capable of determining
continuous position, velocity, time, and in some instances
direction information for an unlimited number of users. Formerly
known as NAVSTAR, the GPS incorporates a plurality of satellites
which orbit the earth in extremely precise orbits. Based on these
precise orbits, GPS satellites can relay their location to any
number of receiving units.
[0114] The GPS system is implemented when a device, specially
equipped to receive GPS data, begins scanning radio frequencies for
GPS satellite signals. Upon receiving a radio signal from a GPS
satellite, the device determines the precise location of that
satellite via one of a plurality of different conventional methods.
The device will continue scanning, in most instances, for signals
until it has acquired at least three different satellite signals
(noting that position is not normally, but can be determined, with
only two signals using other triangulation techniques).
Implementing geometric triangulation, the receiver utilizes the
three known positions to determine its own two-dimensional position
relative to the satellites. This can be done in a known manner.
Additionally, acquiring a fourth satellite signal will allow the
receiving device to calculate its three dimensional position by the
same geometrical calculation in a known manner. The position and
velocity data can be updated in real time on a continuous basis by
an unlimited number of users.
[0115] As shown in FIG. 1, the GPS system is denoted generally by
reference numeral 100. A plurality of satellites 102 are in orbit
about the earth 104. The orbit of each satellite 102 is not
necessarily synchronous with the orbits of other satellites 102
and, in fact, is likely asynchronous. A GPS receiver 106 is shown
receiving spread spectrum GPS satellite signals 108 from the
various satellites 102.
[0116] The spread spectrum signals 108, continuously transmitted
from each satellite 102, utilize a highly accurate frequency
standard accomplished with an extremely accurate atomic clock. Each
satellite 102, as part of its data signal transmission 108,
transmits a data stream indicative of that particular satellite
102. It is appreciated by those skilled in the relevant art that
the GPS receiver device 106 generally acquires spread spectrum GPS
satellite signals 108 from at least three satellites 102 for the
GPS receiver device 106 to calculate its two-dimensional position
by triangulation. Acquisition of an additional signal, resulting in
signals 108 from a total of four satellites 102, permits the GPS
receiver device 106 to calculate its three-dimensional position in
a known manner.
[0117] FIG. 2 is an illustrative representation of electronic
components of a navigation device 200 according to a preferred
embodiment of the present invention, in block component format. It
should be noted that the block diagram of the navigation device 200
is not inclusive of all components of the navigation device, but is
only representative of many example components.
[0118] The navigation device 200 is located within a housing (not
shown). The housing includes a processor 202 connected to an input
device 204 and a display screen 206. The input device 204 can
include a keyboard device, voice input device, touch panel and/or
any other known input device utilised to input information; and the
display screen 206 can include any type of display screen such as
an LCD display, for example. In a particularly preferred
arrangement the input device 204 and display screen 206 are
integrated into an integrated input and display device, including a
touchpad or touchscreen input so that a user need only touch a
portion of the display screen 206 to select one of a plurality of
display choices or to activate one of a plurality of virtual
buttons.
[0119] The navigation device 200 may include an output device 208,
for example an audible output device (e.g. a loudspeaker). As
output device 208 can produce audible information for a user of the
navigation device 200, it is should equally be understood that
input device 204 can include a microphone and software for
receiving input voice commands as well.
[0120] In the navigation device 200, processor 202 is operatively
connected to and set to receive input information from input device
204 via a connection 210, and operatively connected to at least one
of display screen 206 and output device 208, via output connections
212, to output information thereto. Further, the processor 202 is
operably coupled to a memory resource 214 via connection 216 and is
further adapted to receive/send information from/to input/output
(I/O) ports 218 via connection 220, wherein the I/O port 218 is
connectible to an I/O device 222 external to the navigation device
200. The memory resource 214 comprises, for example, a volatile
memory, such as a Random Access Memory (RAM) and a non-volatile
memory, for example a digital memory, such as a flash memory. The
external I/O device 222 may include, but is not limited to an
external listening device such as an earpiece for example. The
connection to I/O device 222 can further be a wired or wireless
connection to any other external device such as a car stereo unit
for hands-free operation and/or for voice activated operation for
example, for connection to an ear piece or head phones, and/or for
connection to a mobile phone for example, wherein the mobile phone
connection may be used to establish a data connection between the
navigation device 200 and the internet or any other network for
example, and/or to establish a connection to a server via the
internet or some other network for example.
[0121] FIG. 2 further illustrates an operative connection between
the processor 202 and an antenna/receiver 224 via connection 226,
wherein the antenna/receiver 224 can be a GPS antenna/receiver for
example. It will be understood that the antenna and receiver
designated by reference numeral 224 are combined schematically for
illustration, but that the antenna and receiver may be separately
located components, and that the antenna may be a GPS patch antenna
or helical antenna for example.
[0122] Further, it will be understood by one of ordinary skill in
the art that the electronic components shown in FIG. 2 are powered
by power sources (not shown) in a conventional manner. As will be
understood by one of ordinary skill in the art, different
configurations of the components shown in FIG. 2 are considered to
be within the scope of the present application. For example, the
components shown in FIG. 2 may be in communication with one another
via wired and/or wireless connections and the like. Thus, the scope
of the navigation device 200 of the present application includes a
portable or handheld navigation device 200.
[0123] In addition, the portable or handheld navigation device 200
of FIG. 2 can be connected or "docked" in a known manner to a
vehicle such as a bicycle, a motorbike, a car or a boat for
example. Such a navigation device 200 is then removable from the
docked location for portable or handheld navigation use. As an
example, FIG. 4 shows a navigation device 200 that may sit on an
arm 252, which itself may be secured to a vehicle dashboard,
window, etc using a suction cup 254. This arm 252 is one example of
a docking station to which the navigation device 200 can be docked.
The navigation device 200 can be docked or otherwise connected to
the arm 252 of the docking station by snap connecting the
navigation device to the arm, for example. To release the
connection between the navigation device 200 and the docking
station, a button on the navigation device 200 may be pressed, for
example. Other equally suitable arrangements for coupling and
decoupling the navigation device to a docking station are well
known to persons of ordinary skill in the art.
[0124] Referring now to FIG. 3, the navigation device 200 may
establish a "mobile" or telecommunications network connection with
a server 302 via a mobile device (not shown) (such as a mobile
phone, PDA, and/or any device with mobile phone technology)
establishing a digital connection (such as a digital connection via
known Bluetooth technology for example). Thereafter, through its
network service provider, the mobile device can establish a network
connection (through the internet for example) with a server 302. As
such, a "mobile" network connection is established between the
navigation device 200 (which can be, and often times is mobile as
it travels alone and/or in a vehicle) and the server 302 to provide
a "real-time" or at least very "up to date" gateway for
information.
[0125] The establishing of the network connection between the
mobile device (via a service provider) and another device such as
the server 302, using an internet (such as the World Wide Web) for
example, can be done in a known manner. This can include use of
TCP/IP layered protocol for example. The mobile device can utilize
any number of communication standards such as CDMA, GSM, WAN,
etc.
[0126] As such, an internet connection may be utilised which is
achieved via data connection, via a mobile phone or mobile phone
technology within the navigation device 200 for example. For this
connection, an internet connection between the server 302 and the
navigation device 200 is established. This can be done, for
example, through a mobile phone or other mobile device and a GPRS
(General Packet Radio Service)-connection (GPRS connection is a
high-speed data connection for mobile devices provided by telecom
operators; GPRS is a method to connect to the internet).
[0127] The navigation device 200 can further complete a data
connection with the mobile device, and eventually with the internet
and server 302, via existing Bluetooth technology for example, in a
known manner, wherein the data protocol can utilize any number of
standards, such as the GSRM, the Data Protocol Standard for the GSM
standard, for example.
[0128] The navigation device 200 may include its own mobile phone
technology within the navigation device 200 itself (including an
antenna for example, or optionally using the internal antenna of
the navigation device 200). The mobile phone technology within the
navigation device 200 can include internal components as specified
above, and/or can include an insertable card (e.g. Subscriber
Identity Module or SIM card), complete with necessary mobile phone
technology and/or an antenna for example. As such, mobile phone
technology within the navigation device 200 can similarly establish
a network connection between the navigation device 200 and the
server 302, via the internet for example, in a manner similar to
that of any mobile device.
[0129] For GPRS phone settings, a Bluetooth enabled navigation
device may be used to correctly work with the ever changing
spectrum of mobile phone models, manufacturers, etc;
model/manufacturer specific settings may be stored on the
navigation device 200, for example. The data stored for this
information can be updated.
[0130] In FIG. 3 the navigation device 200 is depicted as being in
communication with the server 302 via a generic communications
channel 318 that can be implemented by any of a number of different
arrangements. The server 302 and a navigation device 200 can
communicate when a connection via communications channel 318 is
established between the server 302 and the navigation device 200
(noting that such a connection can be a data connection via mobile
device, a direct connection via personal computer via the internet,
etc).
[0131] The server 302 includes, in addition to other components
which may not be illustrated, a processor 304 operatively connected
to a memory 306 and further operatively connected, via a wired or
wireless connection 314, to a mass data storage device 312. The
processor 304 is further operatively connected to transmitter 308
and receiver 310, to transmit and send information to and from
navigation device 200 via communications channel 318. The signals
sent and received may include data, communication, and/or other
propagated signals. The transmitter 308 and receiver 310 may be
selected or designed according to the communications requirement
and communication technology used in the communication design for
the navigation system 200. Further, it should be noted that the
functions of transmitter 308 and receiver 310 may be combined into
a signal transceiver.
[0132] Server 302 is further connected to (or includes) a mass
storage device 312, noting that the mass storage device 312 may be
coupled to the server 302 via communication link 314. The mass
storage device 312 contains a store of navigation data and map
information, and can again be a separate device from the server 302
or can be incorporated into the server 302.
[0133] The navigation device 200 is adapted to communicate with the
server 302 through communications channel 318, and includes
processor, memory, etc as previously described with regard to FIG.
2, as well as transmitter 320 and receiver 322 to send and receive
signals and/or data through the communications channel 318, noting
that these devices can further be used to communicate with devices
other than server 302. Further, the transmitter 320 and receiver
322 are selected or designed according to communication
requirements and communication technology used in the communication
design for the navigation device 200 and the functions of the
transmitter 320 and receiver 322 may be combined into a single
transceiver.
[0134] Software stored in server memory 306 provides instructions
for the processor 304 and allows the server 302 to provide services
to the navigation device 200. One service provided by the server
302 involves processing requests from the navigation device 200 and
transmitting navigation data from the mass data storage 312 to the
navigation device 200. Another service provided by the server 302
includes processing the navigation data using various algorithms
for a desired application and sending the results of these
calculations to the navigation device 200.
[0135] The communication channel 318 generically represents the
propagating medium or path that connects the navigation device 200
and the server 302. Both the server 302 and navigation device 200
include a transmitter for transmitting data through the
communication channel and a receiver for receiving data that has
been transmitted through the communication channel.
[0136] The communication channel 318 is not limited to a particular
communication technology. Additionally, the communication channel
318 is not limited to a single communication technology; that is,
the channel 318 may include several communication links that use a
variety of technology. For example, the communication channel 318
can be adapted to provide a path for electrical, optical, and/or
electromagnetic communications, etc. As such, the communication
channel 318 includes, but is not limited to, one or a combination
of the following: electric circuits, electrical conductors such as
wires and coaxial cables, fibre optic cables, converters,
radio-frequency (RF) waves, the atmosphere, empty space, etc.
Furthermore, the communication channel 318 can include intermediate
devices such as routers, repeaters, buffers, transmitters, and
receivers, for example.
[0137] In one illustrative arrangement, the communication channel
318 includes telephone and computer networks. Furthermore, the
communication channel 318 may be capable of accommodating wireless
communication such as radio frequency, microwave frequency,
infrared communication, etc. Additionally, the communication
channel 318 can accommodate satellite communication.
[0138] The communication signals transmitted through the
communication channel 318 include, but are not limited to, signals
as may be required or desired for given communication technology.
For example, the signals may be adapted to be used in cellular
communication technology such as Time Division Multiple Access
(TDMA), Frequency Division Multiple Access (FDMA), Code Division
Multiple Access (CDMA), Global System for Mobile Communications
(GSM), etc. Both digital and analogue signals can be transmitted
through the communication channel 318. These signals may be
modulated, encrypted and/or compressed signals as may be desirable
for the communication technology.
[0139] The server 302 includes a remote server accessible by the
navigation device 200 via a wireless channel. The server 302 may
include a network server located on a local area network (LAN),
wide area network (WAN), virtual private network (VPN), etc. In
other embodiments, the server 302 may include a personal computer
such as a desktop or laptop computer, and the communication channel
318 may be a cable connected between the personal computer and the
navigation device 200. Alternatively, a personal computer may be
connected between the navigation device 200 and the server 302 to
establish an internet connection between the server 302 and the
navigation device 200. Alternatively, a mobile telephone or other
handheld device may establish a wireless connection to the
internet, for connecting the navigation device 200 to the server
302 via the internet.
[0140] The navigation device 200 may be provided with information
from the server 302 via information downloads which may be
periodically updated automatically or upon a user connecting
navigation device 200 to the server 302 and/or may be more dynamic
upon a more constant or frequent connection being made between the
server 302 and navigation device 200 via a wireless mobile
connection device and TCP/IP connection for example. For many
dynamic calculations, the processor 304 in the server 302 may be
used to handle the bulk of the processing needs, however, processor
210 of navigation device 200 can also handle much processing and
calculation, oftentimes independent of a connection to a server
302.
[0141] As is known in the art, the navigation device 200 may be
configured to provide warnings when a vehicle is approaching a
speed limit enforcement device, such as a mobile or fixed speed
camera. In particular, the warning may be provided when the vehicle
is approaching the speed limit enforcement device at a speed that
is above the legal speed limit for the road. The warnings may
comprise a visual warning on the display 206 of the navigation
device 200, an audible warning, a haptic warning, or any
combination thereof as desired. In order to provide such warnings,
the navigation device has access to a database of speed limit
enforcement devices, which includes at least the location of speed
limit enforcement device and a speed limit for the device. The
database will typically be stored on the navigation device 200,
e.g. in the memory 214, and will be regularly updated with new data
from the server 302 using the communication channel 318. It is
envisaged, however, that the navigation device 200 may only
temporary store portions of the database for speed limit devices in
their immediate vicinity or a planned route.
[0142] The speed cameras in the database each have at least one
attribute, and typically a plurality of attributes, associated
therewith. The attributes can be, for example: a location of the
speed camera; a speed limit associated with the camera; the side of
the road on which the speed camera is operational; and the type of
the speed camera (e.g. a fixed camera, a mobile camera, part of an
average speed trap).
[0143] Due to the nature of speed cameras, e.g. new fixed speed
cameras are continually being installed, fixed speed cameras may be
moved to a new location, mobile speed cameras will often be in
operation for short periods of time, etc, the information in the
database on the server 302 needs to be constantly refreshed to
ensure that it is accurate and up to date. To facilitate this
process, speed cameras in the database each have an associated
confidence value, which reflects how certain it is that the speed
camera is actually still there in the real world and how certain it
is that the attributes for the speed camera in the database are
actually correct. The confidence value for a particular speed
camera can take a value between 0% and 100%, where 0% means that
there is completely no confidence in the camera and conversely 100%
means that there is complete confidence in the camera.
[0144] As will be appreciated, the confidence value for a camera
will change with time as reports are received from users either in
support of, or requesting deletion of, the camera. A report in
support of a camera will cause the confidence value to increase,
while a report requesting deletion of a camera will cause the
confidence value to decrease. It will be understood that a report
supporting a camera may be a report simply confirming the presence
of the camera or it may be a report requesting the modification of
an attribute associated with the camera.
[0145] In addition to the confidence value varying in time due to
received reports, the confidence value associated with a speed
camera is also designed to vary in time, or age, according to a
predetermined decay function. This aging of the confidence value is
depicted in FIG. 5.
[0146] It has been recognised that it is desirable to have
different decay functions based on the type of the speed camera.
For example, and as shown in FIG. 5, a fixed speed camera (shown as
a dashed line) ages at a slower rate than a mobile speed camera
(shown as a solid line). This is to reflect the reality that a
mobile speed camera will in all likelihood have a significantly
shorter lifetime than a fixed speed camera. Any decay function can
be used as desired, but it can include a linear, an exponential or
a polynomial (e.g. quadratic, cubic, etc) decay function.
[0147] As will be appreciated, the decay functions shown in FIG. 5
show how the confidence value associated with a fixed and mobile
speed camera change when no reports for the cameras are received
from users. In practice, reports are continually being received in
relation to a speed camera, thereby pushing the confidence value
for the camera up or down. This is shown in FIG. 6, wherein: 410
shows the confidence value decreasing according to the predefined
decay function; 412 shows the confidence value increasing due to a
received report; and 414 shows the confidence value decreasing due
to a received report.
[0148] The manner by which the confidence value for a particular
speed camera is determined will be described in more detail below
following a description of the architecture of the system in
accordance with an embodiment of the present invention with
reference to FIG. 7.
[0149] As shown in FIG. 7, new speed cameras can be identified, and
subsequently added to the speed camera database 516, in a number of
ways.
[0150] For example, the existence of a speed camera may be
determined following the receipt of a report from a user 500. The
user reports may be generated in any manner on the navigation
devices 200 as appropriate. For example, the navigation device may
have a hard button or soft key (on a touch screen display) that can
be pressed to automatically generate and transmit a report to the
server 302. Such a report may include the location, speed and/or
direction of travel of the navigation device (and thus the vehicle)
at the time the button is pressed. Additional or more accurate
information about a speed camera may subsequently be added to a
report by the user before it is transmitted to the server 302. For
example, the user may provide the actual speed limit for the road
and may also adjust the location of the speed camera as appropriate
(e.g. as the location of the device provided in the report will not
always reflect the actual position of the speed camera, but will
typically be a short distance before or after the actual position
of the camera).
[0151] Speed camera data can also be obtained from various third
parties 502, such as government data, other companies newspapers
and other journalistic sources, etc. The existence of speed cameras
can additionally be determined from sources, such as images
collected by mobile mapping vehicles, and confirmed by moderators
504. It is also envisaged that location of speed cameras can be
inferred from changes in the speed of individual vehicles or
collections of vehicles 506.
[0152] New speed cameras, or modifications to attributes of
existing speed cameras, obtained from one or more of the sources
500, 502, 504 and 506 are received at a fusion engine 510 of the
server 302. It will be understood by those skilled in the art,
however, that speed camera information may be obtained from other
sources, in addition to those described above. At the fusion engine
510, the received speed camera information may be combined with one
or more of: (i) information already existing in a speed camera
database 516; (ii) information from a map database 512, e.g. to
identify the location of a speed camera; and (iii) information from
a user trust database 514, e.g. to provide an indication as to
accuracy of reports previously received from a particular user. The
information from all these sources is combined by the fusion engine
510 to produce new or amended speed cameras entries in the speed
camera database 516.
[0153] For example, when a first report is received indicating the
presence of a new speed camera, a new entry is made in the
database. The attributes for the speed camera will be taken, at
least in part, from the information contained in the report.
Accordingly, the speed camera will be assigned a type: fixed or
mobile, if available, or the type will be determined from the
determined type confidence level as described below. The location,
speed and driving direction for the camera will be that contained
in the report if available, otherwise they will be left blank or
inferred from other sources, such as the map database, data from
mobile mapping vehicles, video from camera-equipped navigation
devices, etc.
[0154] When a subsequent report relating to the same speed camera
is received, the location of the speed camera will be adjusted
according to a weighted average of the locations contained in the
reports, the weighting being based on the trust level of the source
of the reports, e.g. that of the user submitting the report. The
speed limit of the speed camera will similarly be adjusted
according to weighted average of the speeds contained in the
reports based on trust level.
[0155] The fusion engine 510 also serves to generate a confidence
value for new speed cameras that are added to the database 516, and
modify the confidence value as necessary (e.g. following user
reports) for speed cameras already existing in the database 516. A
new confidence value is determined each time a new report is
received, unless the report is received from a completely
distrusted source.
[0156] The confidence value C for a speed camera is calculated by
the fusion engine 510 as a compound value according to the
following formula:
C = .gamma. i = 1 N c i .lamda. i Eqn . 1 ##EQU00001##
c is the partial confidences of attributes associated with the
speed camera (e.g. location, speed, type and size), [0157] .lamda.
is a weight for each partial confidence, i.e. the contribution made
by each confidence type to the total confidence, and [0158] .gamma.
is the weighted ratio between supporting and deletion reports.
[0159] The weights .lamda. are normalised such that:
i = 1 N .lamda. i = 1 Eqn . 2 ##EQU00002##
[0160] In a preferred example, the weight associated with the size
confidence is 80%, the weight associated with the type confidence
is 5%, the weight associated with the speed confidence is 5% and
the weight associated with the location confidence is 10%. It will
be appreciated, however, that the weight for each partial
confidence can take any value as desired provided the requirement
of Equation 2 is fulfilled.
[0161] The weighted ratio .gamma. is a number between 0 and 1 that
represents the fraction of supporting reports received for a speed
camera, i.e. those reports that support the hypothesis that a speed
camera is present, in relation to all reports for that speed
camera. The reports in the ratio are weighted such that a newer
report carries more weight than an older report.
[0162] The partial confidences that are used to determine the
confidence value C are: location confidence C.sub.L; speed
confidence C.sub.S; fixed type confidence C.sub.Tf; mobile type
confidence C.sub.Tm; and size confidence C.sub.N.
[0163] The location confidence C.sub.L provides an indication as to
the accuracy of the estimated location of the speed camera, and is
determined based on a weighted average of the distance between the
location contained in a report and the current speed camera
location, the weighting being based on user trust level. The
location confidence is calculated in a manner such that it is zero
when the weighted average exceeds a maximum value.
[0164] The speed confidence C.sub.S provides an indication as to
the accuracy of the estimated speed limit associated with the speed
camera. The speed confidence C.sub.S is calculated using a
statistical measure of the different speeds received in relevant
reports, each report being weighted according to the trust level of
the source, e.g. of the user. A report is deemed relevant if it
contains speed limit information in a given speed range, e.g. 0 to
200 km/h, and is not older than a predetermined time period, e.g.
365 days.
[0165] The type confidence provides an indication as to the degree
of confidence there is in the type attribute associated with a
speed camera, e.g. whether it is a fixed speed camera or a mobile
speed camera. As mobile and fixed speed cameras differ
significantly in terms of their life and the number of associated
reports, confidence is calculated differently for each type. The
type attribute for a speed camera is set according to the last
report from a moderator, or if there is no such report the type
attribute is set using the relative sizes of C.sub.Tm and C.sub.Tf;
with a speed camera being said to be fixed if C.sub.Tm<C.sub.Tf,
and conversely being said to be mobile if C.sub.Tm>C.sub.Tf.
[0166] The confidence that a speed camera is a mobile camera
C.sub.Tm is set as 100% if the report came from a moderator, but is
otherwise determined based on the relative number of reports
indicating that a camera is a mobile speed camera to the total
number of received reports and the age of the speed camera in the
database 510. The C.sub.Tm value is calculated such that it is zero
when the speed camera has been in the database 510 for more than a
predetermined period of time, and such that each new report that is
received for a speed camera decreases the confidence that the speed
camera is a mobile speed camera. This reflects the situation that
mobile speed cameras only exist for a short period of time, and
thus if a speed camera exists for a relatively long period of time,
then it becomes more likely that the camera is a fixed speed
camera.
[0167] The confidence that a speed is a fixed camera C.sub.Tf is
again set as 100% if the report came from a moderator, but is
otherwise determined based on the age of the camera and also the
number of reports received relating to the camera.
[0168] The size confidence C.sub.N is an indicator of the number of
reports received in relation to a particular speed camera. The size
confidence C.sub.N is calculated such that the first reports
received for a particular speed camera contribute more to the
confidence than subsequent reports.
[0169] As discussed above, the confidence value C decays over time
according to a predetermined decay function. Thus, when a new
report is received for a speed camera already existing in the
database 510, the report changes the aged confidence value, rather
than the previously calculated confidence value. This is achieved
by the introduction of an effective confidence C', wherein:
C'(t)=f(t)C
The decay function f(t) is, in a preferred embodiment, a linear
decay function, wherein f(t)=1-mt. The gradient m is based on the
type of the camera, such a fixed speed camera decays slower then a
mobile speed camera. This aging of the confidence value is shown in
FIG. 5, wherein the effective confidence value for a fixed speed
camera (dashed line) and a mobile speed camera (solid line) is
depicted, for speed cameras on which no reports are received.
[0170] The varying confidence values, or to be more accurate the
effective confidence values, for each of the speed cameras in the
database 510 are continually monitored by the confidence value
monitoring engine 518 (as shown in FIG. 6). The purpose of the
monitoring engine 518 is to determine when the confidence value for
any speed camera falls below one of two predefined thresholds.
These thresholds 400 and 402 can be seen in FIG. 5.
[0171] The first threshold 400 indicates when a speed camera in the
database 510 is active or inactive. When a speed camera has a
confidence value that means it is seen as active in the database,
then mobile devices 200 provide warnings to users as to the
presence of the speed camera and updates relating to the speed
camera, e.g. changed attributes, are sent to the mobile devices
200. Conversely, when a speed camera has a confidence value that
means it is seen as inactive, then mobile devices 200 do not
provide any warnings to users since it is assumed that the speed
camera no longer exists on the road. As will be appreciated, the
use of the first threshold 400 limits the number of false positives
being issued by devices.
[0172] When a speed camera falls below the threshold 400, then a
message 520 is sent to users indicating that the speed camera is
now inactive. The message 520 may include an identifier to identify
the speed camera and an indicator that shows the speed camera is
inactive. Messages 520 may be sent to all users as soon as the
speed camera falls below the threshold level 400. Alternatively,
messages 520 may just be sent to users in the vicinity of the speed
camera, and other users are informed about the change in a periodic
update of the database 516. This reduces the number of
active/inactive status messages that are sent out to users, and
thus the amount of bandwidth needed for operation of the
system.
[0173] The second threshold 402 indicates the beginning of an
intermediate level of confidence, which extends between the
thresholds 400 and 402. It is desirable for any speed cameras that
fall into this region to quickly confirm the presence or absence of
a speed camera, and therefore increase the confidence value for the
camera above the threshold 402 or decrease the confidence value
below the threshold 400. Accordingly, when the confidence value for
a speed camera falls below the threshold 402, messages 522 are sent
to users requesting confirmation of the presence of a speed camera
in the database 510. The messages 522 can also request that a user
confirm a particular attribute associated with the speed camera.
For example, if the confidence value for a speed camera is reduced
due to a lack of confidence in only one attribute, then the
messages may ask a user to confirm this attribute. As will be
appreciated, the mobile devices 200 periodically provide their
current position to the server 302, and may also provide a planned
route to the server 302. This information is used by the server 302
to only send the messages 522 to mobile devices 200 that will pass
the associated speed camera.
[0174] As will be seen from FIG. 6, the reports received from users
in response to the attribute confirmation requests 522 are supplied
to the fusion engine 510 to update the relevant speed cameras in
the database 516.
[0175] The use of active feedback from users can also be used to
confirm the presence of speed cameras that are inferred indirectly,
e.g. from analysing vehicle speed data as discussed above (506).
For example, once a speed camera is determined from analysing
vehicle speed data it can be assigned a confidence value that will
always fall between the thresholds 400 and 402. Thus, the presence
of the speed camera will quickly be confirmed or rejected based on
the responses of users to the messages 522 that are sent out by the
server 302.
[0176] In other embodiments, instead of sending messages 520 and
522 to the mobile devices 200, each time the confidence value of a
speed camera changes due to a received user report 500 or the like
(and not only due to natural decay), then a message is sent to the
mobile devices including a first time indicating when the
confidence value with fall below the second threshold 402 based on
the decay function associated with the camera, and a second time
indicating when the confidence value will fall below the first
threshold 400 based on the decay function associated with the
camera. The message may also include a third time value indicating
when the confidence value falls to a level where the camera is to
be deleted from the database on the mobile devices 200.
[0177] The mobile devices will then perform the actions associated
with these time values. In other words, at the first time, the
mobile devices 200 will generate a message to show (or provide in
some other way) to the user asking for confirmation as to the
existence of the speed camera. Similarly, at the second time, the
mobile devices 200 will stop providing warnings to the driver
relating to the speed camera.
[0178] It will be appreciated that whilst various aspects and
embodiments of the present invention have heretofore been
described, the scope of the present invention is not limited to the
particular arrangements set out herein and instead extends to
encompass all arrangements, and modifications and alterations
thereto.
[0179] For example, whilst the embodiments in the foregoing detail
description refer to specifically to a system for maintaining a
database of speed cameras, it will be understood that a similar
system could be used with other types of points of interest or
dynamic data. In particular, data in an electronic map that is
temporary in nature, such as the availability of parking areas,
either individual spaces or multiple spaces in a parking lot, and
the availability of electric vehicle charging stations could be
maintained using a similar system to that described above. The
system could also be used to control dynamic advertising
displays.
[0180] In this regard, whilst the embodiments in the above detailed
description refer to the use of a predetermined decay function to
age the confidence values, it will be appreciated that any type of
function could be used in the system. For example, a growth
function could be used that increases the confidence value with
time, or a more complex function that both increases and decreases
the confidence value with time.
[0181] Similarly, whilst embodiments described in the foregoing
detailed description refer to GPS, it should be noted that the
mobile devices 200, e.g. navigation apparatus, may utilise any kind
of position sensing technology as an alternative to, or indeed in
addition to, GPS. For example, the navigation apparatus may utilise
other global navigation satellite systems, such as the European
Galileo system. Equally, it is not limited to satellite-based
systems, but could readily function using ground-based beacons or
other kind of system that enables the device to determine its
geographic location.
[0182] It will also be well understood by persons of ordinary skill
in the art that whilst the preferred embodiment may implement
certain functionality by means of software, that functionality
could equally be implemented solely in hardware (for example by
means of one or more SICs (application specific integrated
circuit)) or indeed by a mix of hardware and software.
[0183] Lastly, it should be noted that whilst the accompanying
claims set out particular combinations of features described
herein, the scope of the present invention is not limited to the
particular combinations hereafter claims, but instead extends to
encompass any combination of features or embodiments herein
disclosed irrespective of whether or not that particular
combination has been specifically enumerated in the accompanying
claims at this time.
* * * * *
References