U.S. patent application number 09/770873 was filed with the patent office on 2002-08-01 for gps enabled mobile stations and location methods therefor.
This patent application is currently assigned to Motorola, Inc.. Invention is credited to Alberth, William P. JR., Droste, Scott, Kotzin, Michael.
Application Number | 20020102990 09/770873 |
Document ID | / |
Family ID | 25089970 |
Filed Date | 2002-08-01 |
United States Patent
Application |
20020102990 |
Kind Code |
A1 |
Alberth, William P. JR. ; et
al. |
August 1, 2002 |
GPS ENABLED MOBILE STATIONS AND LOCATION METHODS THEREFOR
Abstract
A satellite positioning system enabled mobile station and method
therefor having a satellite positioning system signal reception
interface, for example a GPS receiver, an information processor
coupled to the satellite positioning system signal reception
interface, the information processor controlling the satellite
positioning system signal reception interface for receiving
satellite positioning system signals upon which mobile station
positioning may be determined based upon a satellite positioning
system based position fix generation rate instruction.
Inventors: |
Alberth, William P. JR.;
(Crystal Lake, IL) ; Kotzin, Michael; (Buffalo
Grove, IL) ; Droste, Scott; (Crystal Lake,
IL) |
Correspondence
Address: |
Motorola, Inc.
Intellectual Property Dept. (RKB)
600 North US Highway 45, AN475
Libertyville
IL
60048
US
|
Assignee: |
Motorola, Inc.
|
Family ID: |
25089970 |
Appl. No.: |
09/770873 |
Filed: |
January 26, 2001 |
Current U.S.
Class: |
455/456.6 ;
455/12.1; 455/427 |
Current CPC
Class: |
G01S 19/34 20130101;
G01S 19/17 20130101; H04B 7/18554 20130101 |
Class at
Publication: |
455/456 ;
455/12.1; 455/427; 455/552 |
International
Class: |
H04Q 007/20 |
Claims
What is claimed is:
1. A method for locating a satellite positioning system enabled
mobile station in a geographical area, comprising: specifying
different satellite positioning system based location fix
generation rates for corresponding portions of the geographical
area; determining within which portion of the geographical area the
mobile station is located; receiving satellite signals at the
mobile station for generating satellite positioning system based
location fixes of the mobile station at the rate specified for the
portion of the geographical area within which the mobile station is
located.
2. The method of claim 1, the mobile station is a GPS enabled
cellular handset and the geographical area includes a cellular
communication network, specifying a GPS based location fix
generation rate for a portion of the cellular communication network
that is different from a GPS based location fix generation rate
specified for another portion of the cellular communication
network; determining within which portion of the cellular
communication network the cellular handset is located; receiving
satellite signals at the cellular handset at a rate for generating
satellite positioning system based location fixes of the cellular
handset at the rate specified for the portion of the cellular
communication network within which the mobile station is
located.
3. The method of claim 2, determining the portion of the cellular
communication network within which the cellular handset is located
by generating a GPS based location fix of the cellular handset.
4. The method of claim 2, specifying the GPS based location fix
generation rate from the cellular communication network.
5. The method of claim 2, specifying the GPS based location fix
generation rate from the cellular handset.
6. The method of claim 2, specifying the GPS based location fix
generation rate based on an identification of a base station
serving the cellular handset.
7. The method of claim 2, specifying the GPS based location fix
generation rate based on a time of day.
8. The method of claim 2, determining a velocity of the cellular
handset, specifying a GPS based location fix generation rate based
on the velocity of the cellular handset, generating the GPS based
location fix at the higher of the rate based on the velocity of the
cellular handset and the rate specified for the portion of the
cellular communication network within which the cellular handset is
located.
9. A method for locating a satellite position system enabled mobile
station, comprising: determining a velocity of the mobile station;
receiving satellite signals at the mobile station at a rate based
on a velocity of the mobile station; generating satellite
positioning system based location fixes of the mobile station based
on the satellite signals at a rate based on the velocity of the
mobile station.
10. The method of claim 9, the satellite positioning system enabled
mobile station is a cellular handset in a cellular communication
network, determining the velocity of the cellular handset by
measuring a fading pitch of a cellular communication network signal
at the mobile station.
11. The method of claim 9, increasing the location fix generation
rate in an increasing proportion to increases in the velocity of
the mobile station, decreasing the location fix generation rate in
a decreasing proportion to decreases in the velocity of the mobile
station.
12. A method for locating a satellite positioning system enabled
mobile station, comprising: specifying a variable satellite
positioning system based location fix generation rate based on a
variable condition; monitoring the variable condition; receiving
satellite signals at the mobile station at a rate for generating a
location fix of the mobile station at the rate specified by the
variable satellite positioning system based location fix generation
rate corresponding to the variable condition monitored.
13. The method of claim 12, the mobile station is a cellular
handset, specifying the location fix generation rate based on the
portion of the cellular communication network within which the
cellular handset is located, determining within which portion of
the cellular communication network the cellular handset is located,
receiving satellite signals at the cellular handset at a rate for
generating location fixes of the cellular handset at the location
fix generation rate specified for the portion of the cellular
communication network within which the cellular handset is
located.
14. The method of claim 13, making the variable satellite
positioning system based location fix generation rate dependent
upon a velocity of the cellular handset, determining a velocity of
the cellular handset, receiving satellite signals at the handset at
a rate for generating the location fix of the cellular handset at a
rate based on the velocity of the cellular handset.
15. The method of claim 14, determining the velocity of the
cellular handset by measuring a fading pitch of a cellular
communication network signal.
16. The method of claim 13, specifying the variable satellite
positioning system based location fix generation rate at the
cellular handset, monitoring the variable condition at the cellular
handset.
17. The method of claim 13, controlling the variable satellite
positioning system based location fix generation rate from the
cellular communication network.
18. The method of claim 13, specifying the variable satellite
positioning system based location fix generation rate based on a
continuously variable condition.
19. The method of claim 13, specifying the variable satellite
positioning system based location fix generation rate based on a
discretely variable condition.
20. The method of claim 13, specifying the variable satellite
positioning system based location fix generation rate from the
cellular communication network.
21. A method for locating a satellite positioning system enabled
mobile station in a geographical area, comprising: specifying
different satellite positioning system based location fix
generation rates for corresponding time periods; determining a
present time period; receiving satellite signals at the mobile
station for generating satellite positioning system based location
fixes of the mobile station at the rate specified for the present
time period.
22. A satellite positioning system enabled mobile station,
comprising: a satellite positioning system signal reception
interface; an information processor coupled to the satellite
positioning system signal reception interface and the memory, the
information processor controlling the satellite positioning system
signal reception interface for receiving satellite positioning
system signals, upon which mobile station positioning may be
determined, at a variable rate based upon a variable satellite
positioning system based position fix generation rate
instruction.
23. The mobile station of claim 22 is a satellite positioning
system enabled cellular handset comprising a wireless communication
network interface coupled to the information processor.
24. The mobile station of claim 23, a memory in the cellular
handset for storing a satellite positioning system based position
fix generation rate instructions that vary with a variable
condition.
25. The mobile station of claim 23, the satellite positioning
system based position fix generation rate instruction specifies a
variable satellite positioning system based position fix generation
rate as a function of location of the cellular handset in the
cellular communication network.
26. The mobile station of claim 23, the satellite positioning
system based position fix generation rate instruction specifies the
satellite positioning system based position fix generation rate as
function of velocity of the mobile station.
27. The mobile station of claim 23, the satellite positioning
system based position fix generation rate instruction specifies the
satellite positioning system based position fix generation rate as
a function of time.
28. The mobile station of claim 23, the satellite positioning
system based position fix generation rate information specifies the
satellite positioning system based position fix generation rate as
a function of an estimated ability of the cellular handset to
receive satellite signals.
Description
FIELD OF THE INVENTIONS
[0001] The present inventions relate generally to locating mobile
stations, and more particularly to locating satellite positioning
system enabled mobile stations.
BACKGROUND OF THE INVENTIONS
[0002] Locating cellular telephone handsets in cellular
communication networks based on a satellite positioning system, for
example the Navigation System with Time and Range (NAVSTAR) global
positioning system (GPS), is one approach likely to be implemented
for supporting enhanced emergency 911 (E-911) services, which will
soon be mandatory in the United States of America.
[0003] Market driven forces are also motivating communications
equipment manufacturers and service providers to more quickly and
accurately locate cellular telephone handsets and other mobile
stations, for example to provide promotional and fee based
value-added services. Satellite positioning system based
positioning will likely be among the contenders for many of these
market opportunities.
[0004] Satellite positioning system enabled mobile stations
generally require a satellite signal receiver interface, which
draws power in some proportion to the rate at which satellite
signals are received and location fixes are generated. Satellite
positioning system based positioning schemes will thus reduce
standby and talk time in battery-operated mobile stations, for
example cellular telephone handsets.
[0005] Additionally, there will likely be service fees associated
with at least some satellite positioning system based positioning
schemes, for example those utilizing terrestrial
network-assistance.
[0006] Reducing the frequency or rate at which the cellular handset
generates and updates satellite positioning system based location
fixes, for example, to conserve battery power and reduce costs
associated therewith, generally increases the time required to
obtain a position fix. In some applications, however, a substantial
delay in the generation of a location fix is undesirable or
unacceptable, for example in E-911 applications where the caller is
in imminent danger, or where the mobile station is moving at a high
rate of speed and will have changed its position significantly by
the time a position fix is obtained.
[0007] The various aspects, features and advantages of the present
inventions will become more fully apparent to those having ordinary
skill in the art upon careful consideration of the following
detailed description of the inventions in conjunction with the
accompanying drawings, which are described below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a GPS enabled cellular handset in a cellular
communication network according to an exemplary embodiment of the
invention.
[0009] FIG. 2 is a cellular communication network having a
plurality of cells with different cellular handset location fix
generation rates according to an exemplary embodiment of the
invention.
[0010] FIG. 3 is a process flow diagram according to an exemplary
implementation of the invention.
DETAILED DESCRIPTION OF THE INVENTIONS
[0011] In some embodiments of the present invention, a satellite
positioning system based position fix generation rate in a
satellite positioning system enabled cellular handset, and more
generally in any other satellite positioning system enabled
receiver, is selectively controlled to balance a desire for ready
and/or more accurate location fix generation with a competing
desire, for example, the desire to reduce power consumption or the
desire to reduce costs associated with generation of the position
fixes, among others.
[0012] In one embodiment of the invention, the generation of
satellite positioning system based location fixes for a mobile
station is selectively controlled based on one or more variable
conditions, for example based on location and/or velocity of the
mobile station, or based on the time of day, etc.
[0013] In one embodiment of the invention, a change in the variable
condition results in a corresponding change in the rate at which
the satellite positioning system based location fix of the mobile
station is generated. The particular relationship between the one
or more variable conditions and the location fix generation rate
depends generally on the particular application.
[0014] In some embodiments of the invention, the relationship
between the location fix generation rate and the variable condition
is predefined, for example in a software program implemented on the
mobile station. In other embodiments, the location fix generation
rate is controlled from a network, for example a cellular
communication network, or in response to a command from the
network.
[0015] In FIG. 1, the satellite positioning system comprises a
constellation of earth orbiting satellites, only some of which,
satellites 2, 4 and 6, are illustrated.
[0016] Known exemplary satellite positioning systems suitable for
use with the present invention include, among others, the
Navigation System with Time and Range (NAVSTAR) Global Positioning
Systems (GPS) in the United States of America, the Global Orbiting
Navigation System (GLONASS) in Russia, and the proposed European
satellite positioning system.
[0017] Satellite positioning system based location fixes of a
satellite positioning system enabled mobile station may be obtained
autonomously or with assistance from terrestrial base stations, for
example with assistance from a cellular communication network or
other ground based network, or as part of a Differential Global
Positioning System (DGPS), as is well known by those having
ordinary skill in the art.
[0018] In the exemplary application of FIG. 1, a GPS enabled
cellular handset 12 is located by a GPS based location fix in a
cellular communication network having a plurality of bases
stations, only one of which, base station 28, is illustrated.
[0019] FIG. 2 illustrates an exemplary cellular communication
network generally comprising a plurality of cells, including cells
A, B, C, D, E, F, G and H, each of which includes a corresponding
base station.
[0020] In FIG. 1, the cellular handset 12, referred to herein more
generally as a "mobile station", comprises generally a satellite
signal reception interface, for example, a GPS receiver measurement
system (MS) 14, for receiving satellite signals 16 from which
satellite based position fixes of the cellular handset are
determined, either autonomously or with assistance or as part of a
DGPS, as discussed above.
[0021] The cellular handset 12 also comprises generally a wireless
communication network interface, for example, a
receiver/transmitter (TXVR) 24 for communicating with the
communication network, for example communications 26 to and/or from
the base station, which may be a serving or neighboring base
station, as the cellular handset moves about the cellular
communication network.
[0022] The cellular handset also comprises generally an information
processor 22 having memory 23 associated therewith. The processor
22 is coupled to the MS 14 and the TXVR 24 for processing
information in association therewith.
[0023] The present inventions are useful for locating any satellite
positioning system enabled mobile station, and are not limited to
locating cellular handsets in cellular communication networks.
Other applications include, for example, the location of GPS
navigation and other satellite positioning system enabled handheld
devices, also referred to herein more generally as mobile stations.
Thus in some embodiments, the mobile station does not necessarily
include the wireless communications interface.
[0024] In one embodiment, satellite positioning system based
position fix generation rate instructions, embodied as software,
are stored in memory at the mobile station or at the cellular
communication network.
[0025] According to this exemplary embodiment, the processor
controls the satellite positioning system signal reception
interface for receiving satellite signals based on a variable
condition under control of the satellite positioning system
position fix generation rate instructions. The rate at which
satellite signals are received at the mobile station, for
generating satellite based positioning fixes, is at least as
frequent as is required to generate location fixes at the rate
specified by the location fix generation rate instructions.
[0026] In applications where the position fix generation rate
instruction software is implemented at the network, location
generation rate information is communicated to the mobile station
via the network interface for use by the processor to control the
rate at which the satellite interface operates to receive satellite
signals. In some embodiments, location fix generation rate
instructions originate from both the network and from the mobile
station, and are implemented according to some predetermined
prioritization.
[0027] In one application of the invention, different location fix
generation rates are specified for corresponding portions of a
geographical area, for example corresponding portions of a cellular
communication network. The portions of the network may be a cell
associated with a base station, or may be a smaller area within a
cell or an area overlapping adjacent cells. These instructions are
stored in the cellular handset or in the cellular communication
network.
[0028] As the mobile station moves about, mobile station location
fixes are generated at a rate based on the location of the mobile
station. The location of the mobile station may be determined by
any one of several positioning schemes.
[0029] In cellular communication networks, the location of the
cellular handset may be determined by a network-based locating
scheme, implemented either at the handset or at the cellular
communication network. Known cellular communication network based
positioning schemes include, among others, those based on network
signal strength measurements at the cellular handset or on signal
timing measurements made at the handset, e.g. by time of arrival
(TOA) or time difference of arrival (TDOA) or by some other
positioning scheme.
[0030] In these and other applications, the location fix generation
rate may also be based upon, or a function of, the time of day
(TOD) or some other variable, either alone or in combination with
the exemplary location variable, discussed above.
[0031] In another embodiment, the mobile station user has the
ability to customize, or program, the cellular handset to specify
different location fix generation rates for different areas and/or
for different time periods.
[0032] In one application, the location fix generation rate is
based on a confidence level input by the user. For example, certain
geographical areas of the network may be designated as being
"safe", "somewhat safe", "not safe", etc. based on the personal
experience of the user. These exemplary designations may be made to
identify safe neighborhoods or alternatively to identify an area
where the user is recreating and would like a heightened degree of
positioning readiness in the event of an emergency.
[0033] In one embodiment, the cellular handset, or mobile station,
is programmed by the user when the mobile station is in a training
mode. The user may specify a confidence level designation for one
or more locations by making a menu entry at the cellular handset
when the handset is in a particular location, at which time a
corresponding location fix may also be generated to correlate the
confidence level designation with a particular location.
[0034] In some embodiments, the user is also able to specify the
area associated with the safety designation, for example by
specifying a radius from the location from which the safety
designation was made. This selection may also be made, for example,
in response to a menu prompt displayed when the cellular handset is
in the training mode. In other embodiments, the safety designation
applies to a default area or radius, for example a mile or so, from
the location from where the confidence level designation was
made.
[0035] The designated confidence levels each have a corresponding
location fix generation rate. In the exemplary application, less
safe designations have higher location fix generation rates. Thus
relatively quick location fixes are generated when the user is in
less safe areas, at the cost of increased power usage, and location
fixes are generated less quickly when the user is in safer
areas.
[0036] Also, the safety designation may have associated therewith a
time attribute, which may also be entered by the user in response
to a menu prompt in the training mode. The confidence level
designations may apply in some areas only during a certain time
period, for example in the evening and early morning hours.
[0037] Alternatively, the location fix generation rates and any TOD
attributes are mapped graphically on a computer with a program that
converts graphical mapping information to location coordinate data
with corresponding location fix generation rate attributes. The
converted mapping is then loaded onto memory in the mobile station
or cellular handset via the Internet, a smart card, Bluetooth,
Irda, etc, or by some other means for use with the location fix
generation rate instructions.
[0038] In the cellular communication network of FIG. 2, cells A, B,
C, D and G have been designated as "safe", and cells E, F and H
have been designated as "not-safe". Additionally, the safety
designations of cells E, F, G and H are a function of the time of
day (TOD). When the time is outside the specified TOD, the location
fix generation rate may revert from the rate corresponding to the
safety designation to some other rate, for example a default
rate.
[0039] In FIG. 2, the safety designations apply to the entire
cells, for example, based on an identification of a base station
serving the cellular handset, but more generally they need not be
so constrained. The user may, for example, make many different
safety designations corresponding to different locations within one
or more cells, as the user moves about the communication network.
Alternatively, these designations may be pre-programmed, for
example by a cellular service provider. In areas where no safety
designation is made, the location fix generation rate may revert to
a default rate.
[0040] As the cellular handset moves about the cellular
communication network, its position is determined, for example, by
a satellite or network based positioning method.
[0041] The location fix of the cellular handset is generated at the
location fix generation rate specified for the portion or area of
the cellular communication network within which the cellular
handset is located. More generally, location fixes of a mobile
station are generated at the location fix generation rate specified
for the portion of the geographical area, which is not necessarily
part of a cellular communication network, within which the mobile
station is located.
[0042] In other embodiments, the location fix generation rate
applied to the cellular handset will be based upon the location
generation rate specified for the location to which the cellular
handset is nearest. In the exemplary confidence level application,
for example, if the cellular handset is closer to a "safe" location
than it is to an "unsafe" location, the location fix generation
rate of the cellular handset will be that designated or specified
for the "safe" location.
[0043] More generally, other criteria, besides safety, may be used
for specifying the location fix generation rate. The location fix
generation rate may be specified based on one or more continuously
or discretely changing variable conditions.
[0044] In another embodiment, the location fix generation rate is
based on a velocity of the mobile station or the cellular handset.
According to this embodiment, a velocity of the mobile station is
determined periodically and the location fix of the mobile station
is generated at a rate based on the most recent velocity
determination.
[0045] The velocity of the mobile station may be determined based
on satellite positioning system measurements or by other known
methods. In the cellular communication network application, the
velocity of the cellular handset is determined by measuring a
fading pitch of a base station signal received at the handset from
the cellular communication network, as is well known to those
having ordinary skill in the art. In this embodiment, the variable
condition is the velocity of the mobile station or cellular
handset.
[0046] FIG. 3 is an exemplary flow diagram 100 for generating
satellite positioning system based location fixes for a cellular
handset based on several variable conditions, including confidence
level designations and time of day.
[0047] In FIG. 3, the handset generates a location fix at block
102. At block 104, it is determined whether the location fix
generated at block 102 is nearer a "safe" or "not safe" designated
area. If the mobile station is nearer a "safe" location than it is
to a "not safe" location, then the cellular handset is considered
to be "safe" and a location fix rate timer is set to a first time,
for example, 5 minutes, at block 106.
[0048] If the mobile station is nearer a "not safe" location than
it is to a "safe" location, then it is considered "not safe" and a
determination is made as to whether the current time is within the
specified TOD, for example between 9:00 pm and 6:00 am, at block
108.
[0049] If the time is not within the specified TOD at block 108,
then the location rate timer is set for the time interval specified
at block 106, otherwise the location rate timer is set to a another
time interval, for example 1 minute, specified at block 112. After
the set timer expires at block 114, another location fix is
generated at block 102. The TOD variable consideration at block 108
may also be applied to the alternative algorithm of block 104
discussed above.
[0050] As noted, software implementing the algorithm of FIG. 4 may
readily be implemented on the cellular handset or at the
network.
[0051] In some embodiments of the invention, the location fix
generation rate is provided to the mobile station by the cellular
communication network. In one application, for example, the
communication network may specify a location fix generation rate
for a particular area or to ensure compliance with E-911
positioning mandates.
[0052] In another application, an E-911 system operator may
specify, through the cellular communication network, the location
fix generation rate for a particular geographical area, for example
an area subject to the occurrence of a natural disaster or civil
unrest, from which a spate of E-911 calls is anticipated and for
which quick and accurate positioning determinations are required.
In this exemplary application, the E-911 operator increases the
location fix generation rate to provide relatively prompt location
identification of anticipated E-911 callers.
[0053] In some embodiments, a location fix generation rate
specified by the network overrides the location fix generation rate
specified at the handset. In some embodiments, the satellite
positioning system location feature of the mobile station and the
source of the predominant location fix generation rate are
selectable by the user, for example by making entries in a mobile
station configuration menu.
[0054] In one implementation, a location fix generation rate
specified by the cellular communication network, overrides a
default location fix rate or a rate specified by the user. In
another implementation, a location fix generation rate based on the
velocity of the mobile station overrides the default rate or the
rate specified by the user, for example where the rate based on
velocity is greater than the default rate or the rate specified by
the user.
[0055] In another implementation, the cellular handset may be
programmed to adopt a higher location fix generation rate when the
cellular phone is powered by means other than a battery, for
example, from an auxiliary power supply plugged into a wall outlet
or vehicle adapter. Thus the variable condition in this embodiment
is whether or not battery power is used.
[0056] While the present invention has been described hereinabove
to enable those of ordinary skill in the art to make and use what
is presently considered to be the best modes thereof, those of
ordinary skill will understand and appreciate that equivalents,
modifications and variations may be made thereto without departing
from the scope and spirit thereof, which is to be limited not by
the exemplary embodiments disclosed herein but by the appended
claims.
* * * * *