U.S. patent application number 16/364676 was filed with the patent office on 2019-11-28 for systems and methods for determining whether a mobile device is inside an environment experiencing adverse pressure variation con.
This patent application is currently assigned to NextNav, LLC. The applicant listed for this patent is NextNav, LLC. Invention is credited to MICHAEL DORMODY, GUIYUAN HAN, BADRINATH NAGARAJAN.
Application Number | 20190364385 16/364676 |
Document ID | / |
Family ID | 68466225 |
Filed Date | 2019-11-28 |
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United States Patent
Application |
20190364385 |
Kind Code |
A1 |
DORMODY; MICHAEL ; et
al. |
November 28, 2019 |
SYSTEMS AND METHODS FOR DETERMINING WHETHER A MOBILE DEVICE IS
INSIDE AN ENVIRONMENT EXPERIENCING ADVERSE PRESSURE VARIATION
CONDITIONS
Abstract
Determining whether a mobile device is inside an environment
experiencing adverse pressure variation conditions. Particular
systems and methods for determining whether a mobile device is
inside an environment experiencing adverse pressure variation
conditions detect a change in pressure measured by a mobile device
that is caused by an HVAC effect of a building or a vehicle,
determine a likelihood that the mobile device is inside a building
based on an estimated position of the mobile device relative to the
building, and determine that the mobile device is inside the
building or inside a vehicle based on the likelihood that the
mobile device is inside the building.
Inventors: |
DORMODY; MICHAEL; (San Jose,
CA) ; HAN; GUIYUAN; (San Jose, CA) ;
NAGARAJAN; BADRINATH; (Cupertino, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NextNav, LLC |
Sunnyvale |
CA |
US |
|
|
Assignee: |
NextNav, LLC
Sunnyvale
CA
|
Family ID: |
68466225 |
Appl. No.: |
16/364676 |
Filed: |
March 26, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62676267 |
May 24, 2018 |
|
|
|
62687735 |
Jun 20, 2018 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01C 21/005 20130101;
G01L 27/005 20130101; H04W 4/029 20180201; G01L 19/00 20130101;
G01C 25/00 20130101; H04W 4/021 20130101; G01C 21/206 20130101;
G01C 5/06 20130101; H04W 4/33 20180201 |
International
Class: |
H04W 4/029 20060101
H04W004/029; G01L 19/00 20060101 G01L019/00; G01L 27/00 20060101
G01L027/00 |
Claims
1. A method for determining whether a mobile device is inside an
environment experiencing adverse pressure variation conditions, the
method comprising: detecting a change in pressure measured by a
mobile device during an Nth predefined time period that meets or
exceeds a threshold value of change; determining if one or more
measurements of an inertial sensor of the mobile device indicate
that the mobile device vertically moved at least a threshold amount
of distance during the Nth predefined time period; if the one or
more measurements of an inertial sensor of the mobile device do not
indicate that the mobile device vertically moved during the Nth
predefined time period at least the threshold amount of distance,
determining an estimated position; determining if the estimated
position is inside a building or within a threshold amount of
distance error from the building; if the estimated position is
inside the building or within the threshold amount of distance
error from the building, determining that the mobile device is
located in the building; and if the estimated position is not
inside the building or not within the threshold amount of distance
error from the building, determining that the mobile device is
located in a vehicle.
2. The method of claim 1, wherein detecting a change in pressure
measured by a mobile device during an Nth predefined time period
that meets or exceeds a threshold value of change comprises:
collecting a plurality of pressure measurements using a pressure
sensor of the mobile device during the Nth predefined time period;
determining, based on the plurality of pressure measurements, a
range of pressures that were measured during the Nth predefined
time period; determining if the range of pressure meets or exceeds
a threshold pressure range value; and if the range of pressure
meets or exceeds the threshold pressure range value, determining
that the change in pressure measured by the mobile device during
the Nth predefined time period meets or exceeds the threshold value
of change.
3. The method of claim 1, wherein detecting a change in pressure
measured by a mobile device during an Nth predefined time period
that meets or exceeds a threshold value of change comprises:
collecting a plurality of pressure measurements using a pressure
sensor of the mobile device during the Nth predefined time period;
determining, based on the plurality of pressure measurements, a
distribution of the pressure measurements that were measured during
the Nth predefined time period; determining if the distribution
meets or exceeds a threshold distribution value; and if the
distribution meets or exceeds the threshold distribution value,
determining that the change in pressure measured by the mobile
device during the Nth predefined time period meets or exceeds the
threshold value of change.
4. The method of claim 1, wherein detecting a change in pressure
measured by a mobile device during an Nth predefined time period
that meets or exceeds a threshold value of change comprises:
collecting a plurality of pressure measurements using a pressure
sensor of the mobile device during the Nth predefined time period;
determining, based on the plurality of pressure measurements, a
range of pressures that were measured during the Nth predefined
time period; determining, based on the plurality of pressure
measurements, a distribution of the pressure measurements that were
measured during the Nth predefined time period; determining if the
range of pressure meets or exceeds a threshold pressure range
value, or if the distribution meets or exceeds a threshold
distribution value; and if the range of pressure meets or exceeds
the threshold pressure range value, or if the distribution meets or
exceeds the threshold distribution value, determining that the
change in pressure measured by the mobile device during the Nth
predefined time period meets or exceeds the threshold value of
change.
5. The method of claim 1, wherein detecting a change in pressure
measured by a mobile device during an Nth predefined time period
that meets or exceeds a threshold value of change comprises:
collecting two pressure measurements using a pressure sensor of the
mobile device during the Nth predefined time period; determining a
difference between the two pressure measurements; determining if
the difference between the two pressure measurements meets or
exceeds a threshold pressure difference value; and if the
difference between the two pressure measurements meets or exceeds
the threshold pressure difference value, determining that the
change in pressure measured by the mobile device during the Nth
predefined time period meets or exceeds the threshold value of
change.
6. The method of claim 1, wherein the method further comprises:
using the location of the mobile device as being inside a building
or inside a vehicle to perform an operation.
7. The method of claim 6, wherein the operation includes
identifying information about the building or the vehicle, wherein
the information specifies a map of the building, or predetermined
HVAC characteristics for the building or the vehicle.
8. The method of claim 6, wherein the operation includes
determining to calibrate a pressure sensor of the mobile device
when the mobile device is not inside the building or the
vehicle.
9. The method of claim 6, wherein the operation includes measuring
HVAC characteristics of the building or the vehicle.
10. The method of claim 1, wherein the method further comprises:
determining if the change in pressure is due to sensor failure;
determining a location confidence value associated with the
estimated position; determining if a threshold amount of a location
confidence area is inside the building; if the threshold amount of
the location confidence area is inside the building, determining
that the mobile device is located in the building; and if the
threshold amount of the location confidence area is not inside the
building, determining that the mobile device is located in a
vehicle.
11. One or more non-transitory machine-readable media embodying
program instructions that, when executed by one or more machines,
cause the one or more machines to implement a method for
determining whether a mobile device is inside an environment
experiencing adverse pressure variation conditions, the method
comprising: detecting a change in pressure measured by a mobile
device during an Nth predefined time period that meets or exceeds a
threshold value of change; determining if one or more measurements
of an inertial sensor of the mobile device indicate that the mobile
device vertically moved at least a threshold amount of distance
during the Nth predefined time period; if the one or more
measurements of an inertial sensor of the mobile device do not
indicate that the mobile device vertically moved during the Nth
predefined time period at least the threshold amount of distance,
determining an estimated position; determining if the estimated
position is inside a building or within a threshold amount of
distance error from the building; if the estimated position is
inside the building or within the threshold amount of distance
error from the building, determining that the mobile device is
located in the building; and if the estimated position is not
inside the building or not within the threshold amount of distance
error from the building, determining that the mobile device is
located in a vehicle.
12. A system for determining whether a mobile device is inside an
environment experiencing adverse pressure variation conditions, the
system comprising one or more machines configured to perform a
method comprising: detecting a change in pressure measured by a
mobile device during an Nth predefined time period that meets or
exceeds a threshold value of change; determining if one or more
measurements of an inertial sensor of the mobile device indicate
that the mobile device vertically moved at least a threshold amount
of distance during the Nth predefined time period; if the one or
more measurements of an inertial sensor of the mobile device do not
indicate that the mobile device vertically moved during the Nth
predefined time period at least the threshold amount of distance,
determining an estimated position; determining if the estimated
position is inside a building or within a threshold amount of
distance error from the building; if the estimated position is
inside the building or within the threshold amount of distance
error from the building, determining that the mobile device is
located in the building; and if the estimated position is not
inside the building or not within the threshold amount of distance
error from the building, determining that the mobile device is
located in a vehicle.
13. The one or more non-transitory machine-readable media of claim
11, wherein detecting a change in pressure measured by a mobile
device during an Nth predefined time period that meets or exceeds a
threshold value of change comprises: collecting a plurality of
pressure measurements using a pressure sensor of the mobile device
during the Nth predefined time period; determining, based on the
plurality of pressure measurements, a range of pressures that were
measured during the Nth predefined time period; determining if the
range of pressure meets or exceeds a threshold pressure range
value; and if the range of pressure meets or exceeds the threshold
pressure range value, determining that the change in pressure
measured by the mobile device during the Nth predefined time period
meets or exceeds the threshold value of change.
14. The one or more non-transitory machine-readable media of claim
11, wherein detecting a change in pressure measured by a mobile
device during an Nth predefined time period that meets or exceeds a
threshold value of change comprises: collecting a plurality of
pressure measurements using a pressure sensor of the mobile device
during the Nth predefined time period; determining, based on the
plurality of pressure measurements, a distribution of the pressure
measurements that were measured during the Nth predefined time
period; determining if the distribution meets or exceeds a
threshold distribution value; and if the distribution meets or
exceeds the threshold distribution value, determining that the
change in pressure measured by the mobile device during the Nth
predefined time period meets or exceeds the threshold value of
change.
15. The one or more non-transitory machine-readable media of claim
11, wherein detecting a change in pressure measured by a mobile
device during an Nth predefined time period that meets or exceeds a
threshold value of change comprises: collecting a plurality of
pressure measurements using a pressure sensor of the mobile device
during the Nth predefined time period; determining, based on the
plurality of pressure measurements, a range of pressures that were
measured during the Nth predefined time period; determining, based
on the plurality of pressure measurements, a distribution of the
pressure measurements that were measured during the Nth predefined
time period; determining if the range of pressure meets or exceeds
a threshold pressure range value, or if the distribution meets or
exceeds a threshold distribution value; and if the range of
pressure meets or exceeds the threshold pressure range value, or if
the distribution meets or exceeds the threshold distribution value,
determining that the change in pressure measured by the mobile
device during the Nth predefined time period meets or exceeds the
threshold value of change.
16. The one or more non-transitory machine-readable media of claim
11, wherein detecting a change in pressure measured by a mobile
device during an Nth predefined time period that meets or exceeds a
threshold value of change comprises: collecting two pressure
measurements using a pressure sensor of the mobile device during
the Nth predefined time period; determining a difference between
the two pressure measurements; determining if the difference
between the two pressure measurements meets or exceeds a threshold
pressure difference value; and if the difference between the two
pressure measurements meets or exceeds the threshold pressure
difference value, determining that the change in pressure measured
by the mobile device during the Nth predefined time period meets or
exceeds the threshold value of change.
17. The one or more non-transitory machine-readable media of claim
11, wherein the method further comprises: using the location of the
mobile device as being inside a building or inside a vehicle to
perform an operation.
18. The one or more non-transitory machine-readable media of claim
17, wherein the operation includes identifying information about
the building or the vehicle, wherein the information specifies a
map of the building, or predetermined HVAC characteristics for the
building or the vehicle.
19. The one or more non-transitory machine-readable media of claim
17, wherein the operation includes determining to calibrate a
pressure sensor of the mobile device when the mobile device is not
inside the building or the vehicle.
20. The one or more non-transitory machine-readable media of claim
17, wherein the operation includes measuring HVAC characteristics
of the building or the vehicle.
21. The one or more non-transitory machine-readable media of claim
11, wherein the method further comprises: determining if the change
in pressure is due to sensor failure; determining a location
confidence value associated with the estimated position;
determining if a threshold amount of a location confidence area is
inside the building; if the threshold amount of the location
confidence area is inside the building, determining that the mobile
device is located in the building; and if the threshold amount of
the location confidence area is not inside the building,
determining that the mobile device is located in a vehicle.
Description
TECHNICAL FIELD
[0001] Aspects of this disclosure generally pertain to positioning
of mobile devices.
BACKGROUND
[0002] Determining the exact location of a mobile device (e.g., a
smart phone operated by a user) in an environment can be quite
challenging, especially when the mobile device is located in an
urban environment or is located within a building. Imprecise
estimates of the mobile device's altitude, for example, may have
life or death consequences for the user of the mobile device since
the imprecise altitude estimate can delay emergency personnel
response times as they search for the user on multiple floors of a
building. In less dire situations, imprecise altitude estimates can
lead a user to the wrong area in an environment.
[0003] Different approaches exist for estimating an altitude of a
mobile device. In a barometric-based positioning system, altitude
can be computed using a measurement of pressure from a calibrated
pressure sensor of a mobile device along with ambient pressure
measurement(s) from a network of calibrated reference pressure
sensors and a measurement of ambient temperature from the network
or other source. An estimate of an altitude of a mobile device
(h.sub.mobile) can be computed by the mobile device, a server, or
another machine that receives needed information as follows:
h mobile = h sensor - RT remote gM ln ( P sensor P mobile ) , (
Equation 1 ) ##EQU00001##
where P.sub.mobile is the estimate of pressure at the location of
the mobile device by a pressure sensor of the mobile device,
P.sub.sensor is an estimate of pressure at the location of a
reference pressure sensor that is accurate to within a tolerated
amount of pressure from true pressure (e.g., less than 5 Pa),
T.sub.remote is an estimate of temperature (e.g., in Kelvin) at the
location of the reference pressure sensor or a different location
of a remote temperature sensor, h.sub.sensor is an estimated
altitude of the reference pressure sensor that is estimated to
within a desired amount of altitude error (e.g., less than 1.0
meters), g corresponds to the acceleration due to gravity, R is a
gas constant, and M is molar mass of air (e.g., dry air or other).
The minus sign (-) may be substituted with a plus sign (+) in
alternative embodiments of Equation 1, as would be understood by
one of ordinary skill in the art. The estimate of pressure at the
location of the reference pressure sensor can be converted to an
estimated reference-level pressure that corresponds to the
reference pressure sensor in that it specifies an estimate of
pressure at the latitude and longitude of the reference pressure
sensor, but at a reference-level altitude that likely differs from
the altitude of the reference pressure sensor. The reference-level
pressure can be determined as follows:
P ref = P sensor .times. exp ( - gM ( h ref - h sensor ) RT remote
) , ( Equation 2 ) ##EQU00002##
where P.sub.sensor is the estimate of pressure at the location of
the reference pressure sensor, P.sub.ref is the reference-level
pressure estimate, and h.sub.ref is the reference-level altitude.
The altitude of the mobile device h.sub.mobile can be computed
using Equation 1, where h.sub.ref is substituted for h.sub.sensor
and P.sub.ref is substituted for P.sub.sensor. The reference-level
altitude h.sub.ref may be any altitude and can be set at mean
sea-level (MSL). When two or more reference-level pressure
estimates are available, the reference-level pressure estimates are
combined into a single reference-level pressure estimate value
(e.g., using an average, weighted average, or other suitable
combination of the reference pressures), and the single
reference-level pressure estimate value is used for the
reference-level pressure estimate P.sub.ref.
[0004] In some cases, the accuracy of a computed altitude for a
mobile device located in an indoor environment (e.g., a building or
a vehicle) is affected by a stack/chimney effect and/or an HVAC
(heating, ventilation, and air conditioning) effect of that indoor
environment. The stack/chimney effect in an environment is
typically characterized by an environment's leakiness, and affects
a pressure profile of an environment based on a difference between
temperature inside the environment and temperature outside the
environment. When an HVAC effect is present in an environment,
sudden and significant pushing or pulling of pressure (e.g., from a
deliberate over-pressurization or under-pressurization) in the
environment can occur while a similar push or pull of pressure does
not occur outside the environment. As a result, an estimated
altitude computed using pushed or pulled pressure values in the
environment can translate to meters of measured altitude error.
Knowing when an HVAC effect is present in an environment can help
determine when estimated altitudes are likely to have too much
error and need to be ignored or adjusted.
[0005] Different approaches for detecting if a mobile device is
located in an environment in which an adverse pressure variation
effect (e.g., an HVAC effect) is affecting pressure measurements
are described herein. The result of these approaches--e.g., a
determination as to whether the mobile device is inside a
particular environment (e.g., a building or vehicle)--is highly
useful in various applications, such as determining when estimated
altitudes are likely to have too much error if based on measurement
of pressure determined from inside the environment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1A illustrates pressure profiles inside a building,
inside a vehicle, and outside the building and the vehicle during a
first time period.
[0007] FIG. 1B illustrates pressure profiles inside a vehicle and
outside the vehicle during a second time period when an HVAC effect
in the vehicle results in a pressure profile inside the vehicle
that is not aligned with a pressure profile of the outside during
the second time period.
[0008] FIG. 1C illustrates pressure profiles inside a building and
outside the building during a third time period when an HVAC effect
in the building results in a pressure profile inside the building
that is not aligned with a pressure profile of the outside during
the third time period.
[0009] FIG. 2 depicts a process for determining whether a mobile
device is inside an environment experiencing adverse pressure
variation conditions.
[0010] FIG. 3A depicts a first process for detecting a change in
pressure measured by a mobile device that meets or exceeds a
threshold value of change.
[0011] FIG. 3B depicts a second process for detecting a change in
pressure measured by a mobile device that meets or exceeds a
threshold value of change.
[0012] FIG. 3C depicts a third process for detecting a change in
pressure measured by a mobile device that meets or exceeds a
threshold value of change.
[0013] FIG. 3D depicts a fourth process for detecting a change in
pressure measured by a mobile device that meets or exceeds a
threshold value of change.
[0014] FIG. 4 illustrates pressure profiles resulting from
different environments with different HVAC effects, where the
pressure profiles do not align with a pressure profile of an
environment with no HVAC effect.
[0015] FIG. 5A and FIG. 5B illustrate an approach for determining
when a mobile device is expected to be inside or outside a
building.
[0016] FIG. 6 illustrates components of a transmitter, a mobile
device, and a server.
DETAILED DESCRIPTION
[0017] Different approaches for detecting if a mobile device is
located in an environment in which an adverse pressure variation
effect (e.g., an HVAC effect) is affecting pressure measurements
are described herein. The result of these approaches--e.g., a
determination as to whether the mobile device is inside a
particular environment (e.g., a building or vehicle)--is highly
useful in various applications that are also described herein.
[0018] Different environments can create an HVAC effect. One
example of such an environment includes a well-sealed,
climate-controlled building or a clean room. Another example is a
vehicle with a fairly air-tight seal. From field data, it has been
observed that the HVAC effect of an environment manifests as sudden
jumps (up or down) in pressure measured by a pressure sensor inside
the environment, where the sudden jumps are not reflected in
outdoor pressures measured by network weather sensors. The
resultant pressure values after sudden jumps can be transient by
lasting only a short period of time (e.g., up to a few seconds), or
sustained by lasting for long periods of time (e.g., several
hours). In some cases, resultant pressure values are sustained
until an operator of a mobile device with the measuring pressure
sensor moves. Recorded jumps can occur at particular times of the
day (e.g., when an HVAC system turns on), or when a stimulus is
introduced into an environment, such as when a window or door is
opened. An example of different pressure profiles is found in FIG.
4, which shows different kinds of pressure profiles showing jumps
caused by an HVAC effect. As shown, one pressure profile includes
transient jumps (e.g., HVAC-detected #3) and two other pressure
profiles include sustained jumps (e.g., HVAC-detected #1, and
HVAC-detected #2). The overall pressure contours (e.g., curves) of
each of the pressure profiles may appear to be similar, but the
differences in pressure between pressure profiles differ before and
after jumps in a way that can introduce error into altitude
computation. These differences in pressure between pressure
profiles before and after jumps in one of the pressure profiles
demonstrate that the pressure profiles are not "aligned" with each
other.
[0019] By way of example, FIG. 1A illustrates pressure profiles
inside a building, inside a vehicle, and outside the building and
the vehicle during a first time period when any HVAC effect in the
building and any HVAC effect in the vehicle are minimal such that
the pressure profiles during the first time period inside the
building, inside the vehicle, and outside are aligned with each
other. The three pressure profiles are shown as offset from each
other to illustrate the same contour of each profile. However, in a
situation where the pressure profiles are for a common altitude
(e.g. 1 m above the ground), the three pressure profiles would
align to virtually the same value. FIG. 1B illustrates possible
pressure profiles inside the vehicle and outside the vehicle during
a second time period when an HVAC effect in the vehicle results in
a pressure profile inside the vehicle that is not aligned with the
pressure profile of the outside for the entire period of time
(e.g., there are jumps in the pressure profile of the vehicle
without corresponding jumps in the pressure profile of the outside
environment). As shown, threshold changes in pressure can be
negative or positive. Alternatively, the pressure profile of the
vehicle could resemble the pressure profile shown for the building
in FIG. 1C (with or without the peaks). FIG. 1C illustrates
pressure profiles inside the building and outside the building
during a third time period when an HVAC effect in the building
results in a pressure profile inside the building that is not
aligned with the pressure profile of outside for the entire period
of time (e.g., there are sustained jumps in the pressure profile of
the building without corresponding sustained jumps in the pressure
profile of the outside environment). As shown, threshold changes in
pressure can be negative or positive. Alternatively, the pressure
profile of the building could not have the peaks, or could resemble
the pressure profile shown for the vehicle in FIG. 1B.
[0020] Knowing if a mobile device is located inside an environment
affected by an HVAC effect can be helpful for many reasons. If HVAC
characteristics of an environment (e.g., a building) are known,
then those HVAC characteristics can be used to constrain a computed
position (latitude, longitude, and/or altitude) of a mobile device
as follows: (i) if a mobile device is determined to be in an
environment affected by an HVAC effect (e.g., jumps in pressure are
measured), but a computed position of that mobile device indicates
that the mobile device is outside, the computed position can be
ignored or modified to reside inside a nearby building; or (ii) if
a computed position of a mobile device is determined to be inside a
building with a known HVAC effect, but no such HVAC effect is
detected by the mobile device, then the computed position can be
ignored or modified to be outside the building.
[0021] Monitoring an HVAC effect is also useful for concluding
whether a mobile device is located inside or outside an environment
(e.g., a building) affected by an HVAC effect. Once a conclusion is
made that a mobile device is inside or outside an environment,
further actions can be taken--e.g., a determination can be made
that a pressure sensor of the mobile device cannot be calibrated
using pressure data during detected jumps or while the HVAC effect
is present; e.g., a determination can be made that position
computations need to be adjusted to account for the HVAC effect or
other effects inside the environment; e.g., a map of the
environment can be accessed and used for navigation or presenting
other information to a user of the mobile device; and e.g.,
estimated altitudes are constrained to known minimum and/or maximum
altitudes of the indoor environment or outdoor terrain depending on
whether the mobile device is located within an indoor environment
or on outdoor terrain.
[0022] Detecting an HVAC effect can also be used with other
information to support certain conclusions. For example, if an HVAC
effect is detected, and if the mobile device is moving at a speed
or acceleration that is only possible in a vehicle, a conclusion
can be made that the mobile device is in a vehicle.
[0023] The detection of a mobile device in an environment affected
by an HVAC effect can also activate an application that collects
pressure measurements for later use in characterizing the HVAC
characteristics of the environment. For example, any recorded jumps
can be time-stamped and associated with a location inside an
environment (e.g., a floor or a room of a building, or a section or
location of a vehicle) and then stored as data depicting an HVAC
effect of the environment at particular times. Over a variety of
different times and days, the HVAC characteristics of the
environment can be mapped. Any mapped HVAC characteristics can be
used to adjust measured pressures in order to account for any
detected HVAC effect of the environment.
[0024] Similarly, the detection of a mobile device in an
environment affected by an HVAC effect can also activate an
application that collects data used to measure the energy
efficiency of an HVAC system in a LEED certified building. In some
cases, the strength of a detected HVAC effect can correlate to a
size of the HVAC system of an environment. Knowledge of the size
can be used to determine an actual building in which a user is
located, or a make and model of a vehicle in which a user is
riding.
[0025] Having described the benefits of knowing when an HVAC effect
is affecting pressure measured by a mobile device of a user,
attention is now turned to different approaches for detecting an
HVAC effect, and then using knowledge of any detected HVAC effect
to determine the type of environment in which the user is
most-likely to be located before performing further optional
operations.
[0026] A first approach for detecting an HVAC effect involves
detecting when users are inside an environment (e.g., a building or
vehicle) that has a strong HVAC effect, and determining the type of
environment. The detection involves confirming if a detected jump
in measured pressure is caused by an HVAC effect or a change in
altitude of a mobile device. An additional test may be performed to
first confirm that the detected jump occurred without a
corresponding jump in outdoor pressure. If a sudden change in
pressure is due to a change in altitude of a mobile device (e.g.,
from an elevator), an inertial sensor of the mobile device (e.g.,
an accelerometer) can confirm if an altitude change occurred. If
the inertial sensor detects that the mobile device has not changed
altitudes, or has not changed an amount of altitude consistent with
the change in pressure, then the change in pressure is assumed to
be caused by an HVAC effect. If inertial information is
unavailable, information about a building can be used to constrain
vertical displacement of a mobile device--e.g., a query to a
building database can retrieve the number of floors or height of
the building, and if the building is short or only has 1 floor, it
would likely indicate the user did not change floors. Since the
change in pressure could be caused by the mobile device entering or
exiting an environment affected by an HVAC effect, an additional
evaluation must be made as to the likelihood the mobile device was
inside the environment when the jump in pressure was detected. One
embodiment computes an estimate of the position of the mobile
device when the mobile device detected the pressure jump. A
location confidence value (e.g., an amount of error in the
estimated position) may also be computed. An area of possible
positions of the mobile device is determined (e.g., a circle
centered on the estimated position with a radius equal to the
location confidence value and optionally scaled by a scale factor).
The area of possible positions is compared to an area of accessible
locations of a building that is within the amount of error from the
estimated position of the mobile device (e.g., a building polygon).
If an amount of the area of possible positions of the mobile device
that overlaps the area of accessible locations of the building
meets or exceeds a threshold percentage (e.g., 50% or other), then
a determination is made that the mobile device is inside the
building, and that the detected pressure change was caused by the
building's HVAC system. If the amount of the area of possible
positions of the mobile device that overlaps the area of accessible
locations of the building does not meet or exceed the threshold
percentage, then one of two conclusions can be made: (1) the mobile
device entered a vehicle with strong HVAC effect; (2) the mobile
device is outside the building (e.g., having existed an environment
with strong HVAC effect). In one embodiment, the only conclusion is
that the mobile device entered a vehicle with strong HVAC effect.
In another embodiment, additional analysis of recorded pressure
measurements can be used to determine which conclusion is correct.
If an HVAC effect continues to be detected (e.g., additional jumps
in pressure are detected), the first conclusion may be made--e.g.,
the mobile device entered a vehicle with strong HVAC effect. If any
detected movement of the mobile device (e.g., via an inertial
sensor or a series of estimated positions) meets or exceeds an
amount of movement that is only possible in a vehicle, the first
conclusion may be made--e.g., the mobile device entered a vehicle
with strong HVAC effect. If no HVAC effect continues to be
detected, and if any detected movement of the mobile device does
not meet or exceed an amount of movement that is only possible in a
vehicle, then the second conclusion may be made--e.g., the mobile
device is outside.
[0027] The first approach described above may be carried out using
different mobile devices or the same mobile device during different
periods of time, and data characterizing an environment's HVAC
system can be collected and associated with the type of environment
that is detected (e.g., a particular building, a vehicle used by a
user). A crowd-sourced approach where data is collected by
different mobile devices can be used to characterize an
environment's HVAC system. With enough users across a variety of
times, a building's HVAC system could be characterized, and the
characterization can be used to determine the HVAC properties of
the building, such as magnitudes of HVAC push/pull, frequencies of
HVAC push/pull, and durations of HVAC push/pull of the building
during particular time periods. An HVAC system of a vehicle used by
a user (e.g., a car, a bus, a train, or other vehicle) can also be
characterized, and the characterization can be used to determine
the HVAC properties of the vehicle, such as magnitudes of HVAC
push/pull, frequencies of HVAC push/pull, and durations of HVAC
push/pull of the vehicle during particular time periods. Data on a
user's motion can also be correlated to determine a user's
preference in HVAC usage.
[0028] A second approach for detecting an HVAC effect is shown in
FIG. 2, which depicts a process for determining whether a mobile
device is inside an environment experiencing adverse pressure
variation conditions, and then determining a particular environment
in which the mobile is believed to be located.
[0029] As shown in FIG. 2, a change in pressure measured by a
mobile device during an Nth predefined time period that meets or
exceeds a threshold value of change is detected during step 210.
Different embodiments of step 210 are discussed later with
reference to FIG. 3A, FIG. 3B, FIG. 3C, and FIG. 3D. The predefined
time periods can be set to any length of time (e.g., 60 seconds or
less, an amount of time during which two consecutive measurements
of pressure are made by a pressure sensor of the mobile device, up
to about 15 minutes where atmospheric pressure variation is about
10-20 Pa in change over a 15-minute period during the middle of the
day). If the length of time between measurements is too long (e.g.,
one or more hours in some embodiments), part of a detected pressure
change may be attributed to atmospheric pressure variation, not
HVAC conditions. That part could be determined using outdoor
pressure measurements, and then removed from analysis.
[0030] Optionally, during step 210, a determination is made as to
whether the change in measured pressure is due to failure of the
pressure sensor. In one embodiment of step 210 that optionally
determines if the change in pressure measured by the mobile device
is due to failure of the pressure sensor instead of HVAC
conditions, the change in pressure is compared to a maximum
threshold change in pressure that specifies an amount of pressure
change that is not physically possible (e.g., a change of 100,000
Pa) in a specified period of time (e.g., a predefined number of
seconds), and the change in pressure measured by the mobile device
is determined to be due to sensor failure instead of HVAC
conditions when the change in pressure exceeds the maximum
threshold change. Alternatively, if a measurement of pressure or a
series of pressure measurements are zero or not physically
possible, then a determination may be made that the change in
pressure measured by the mobile device is due to sensor failure
instead of HVAC conditions.
[0031] During step 220, after the change in pressure is detected, a
determination is made as to whether measurement(s) of inertial
sensor(s) of the mobile device indicate that the mobile device
vertically moved during the Nth predefined time period. If the
measurement(s) of the inertial sensor(s) do not indicate the mobile
device vertically moved at all or in excess of a threshold vertical
movement, the process proceeds to step 230 discussed below. If the
measurement(s) of the inertial sensor(s) indicate the mobile device
vertically moved any distance or in excess of the threshold
vertical movement, an assumption is made that the change in
pressure is due to the mobile device changing altitudes during the
vertical movement, and the process returns to step 210. Examples of
the threshold vertical movement include an amount of acceleration
(e.g., 10 m/s.sup.2), an amount of speed (e.g., 2 m/s), or an
amount of distance (e.g., 3 meters or more). Alternatively, during
step 220, the change in measured pressure is used to determine an
expected change in vertical distance, which is compared to an
estimated amount of vertical movement indicated by the
measurement(s) of the inertial sensor(s). The process returns to
step 210 if the expected change in vertical distance is within a
threshold amount of distance from estimated amount of vertical
movement. Otherwise, the process advances to step 230. Examples of
inertial sensors include accelerometers or other suitable sensors.
If inertial information is unavailable, information about a
building can be used to constrain vertical displacement of a mobile
device--e.g., a query to a building database can retrieve the
number of floors or height of the building, and if the building is
short or only has 1 floor, it would likely indicate the user did
not change floors.
[0032] During step 230, a determination is made that the mobile
device is located in an environment with an HVAC effect that caused
the change in pressure.
[0033] During step 240, an estimated position (e.g., latitude and
longitude) is determined. Optionally, a location confidence value
associated with the estimated position is determined. By way of
example, the location confidence value may be defined as the
expected error in an estimated position, which may be based upon
individual errors feeding into the process used for determining the
estimated position. For instance, the location confidence value is
small for an estimated position determined using three or more
distributed GNSS signals received by a mobile device with
unobstructed views of the GNSS satellites from which the signals
were received (i.e., the estimated position is considered to be
highly-accurate). Alternatively, the location confidence value is
larger for an estimated position determined using a GNSS signal
received by a mobile device with an obstructed view of the GNSS
satellite from which the signal was received (i.e., the estimated
position is considered to have error due to that signal).
[0034] In different embodiments of step 240, the estimated position
is determined using known techniques of a GNSS network, a
terrestrial transmitter network, a WiFi network, or other known
approaches.
[0035] In one embodiment of step 240, latitude and longitude are
estimated at a point in time when the change in pressure is
detected. Since the change in pressure is assumed to be caused by
an HVAC effect of a building or vehicle, the estimated latitude and
longitude determined at the time the change is detected serves to
confirm that assumption. Estimated latitude and longitude
determined before the change in pressure is detected can be used to
further confirm an assumption that the detected change in pressure
is caused by an HVAC effect of a building. For example, if a
location confidence area based on an estimated latitude and
longitude determined before the change in pressure is detected
overlaps M % of a building, and another location confidence area
based on an estimated latitude and longitude determined after the
change in pressure is detected overlaps N % of the building, where
N % is greater than M %, then it is highly likely the mobile device
entered the building. In some embodiments, it is highly likely the
mobile device entered the building only when N is much greater than
M--e.g., when the difference in overlap between N % and M % exceeds
a threshold percentage like 50%. Other I/O/D techniques known in
the art that could be used in place of or with this outlined
technique of using the overlap of a building (e.g. GNSS signal
strength, etc.).
[0036] During step 250, a determination is made as to whether the
estimated position is inside a building (or within a threshold
amount of distance error from the building), or if a threshold
amount of a location confidence area is inside the building.
Examples of the threshold amount include 30%, 50%, 70% or more.
[0037] One example of a location confidence area includes a
circular area centered at the estimated position with a radius
equal to the location confidence value, or equal to the location
confidence value multiplied by a scale factor. The location
confidence area may alternatively have different shapes other than
a circle, including a square with location confidence equal to half
the side of the square. Other shapes are possible, including (ii)
any polygon, (iii) an ellipsoid, (iv) a network area in which the
mobile device received a signal from the network, or (v) others. By
way of example, the scale factor may be a predefined number (e.g.,
a number greater than 1, or a number less than 1). In one
embodiment, the scale factor S is determined a priori by
determining, for one or a variety of location morphologies,
estimated positions of the mobile device (or a representative model
device of the mobile device) and location confidence values for the
estimated positions when the mobile device or model thereof is at
different surveyed locations (e.g., locations with known position
coordinates) in the one type or a variety of location morphologies.
Examples of location morphologies include dense urban, urban,
suburban, and rural morphologies. For each estimated position and
corresponding location confidence value, a determination is made as
to whether the estimated position is within the corresponding
location confidence value from the corresponding surveyed location
at which the estimated position was determined. A percentage of
times when the estimated positions are within their corresponding
location confidence values from their corresponding surveyed
locations is determined (e.g., 60%). A desired percentage is
determined (e.g., 90%). A determination is made as to whether the
determined percentage of times meets or exceeds the desired
percentage. If not, the scale factor is determined to be a number
that, when multiplied to each of the location confidence values
results in a percentage of times (e.g., .gtoreq.90%) when the
estimated positions are within a product of their corresponding
location confidence values and the scale factor from their
corresponding surveyed locations that meets or exceeds the desired
percentage (90%). Once the scale factor is computed for the mobile
device, or for a representative model of the mobile device, the
scale factor is stored for later use. In one embodiment that uses a
scale factor, a single scale factor is determined a priori for the
mobile device. In another embodiment that uses a scale factor,
different scale factors are determined a priori for different
morphologies (e.g., a first scale factor for a first type of
morphology, . . . , and an nth scale factor for an nth type of
morphology, for different types of morphologies like dense urban,
urban, suburban, rural, or other morphologies).
[0038] If the result of step 250 is yes, the mobile device is
determined to be located in the building (step 260a). If the result
of step 250 is no, the mobile device is determined to be located in
a vehicle (step 260b), such as a car, bus, train or other
vehicle.
[0039] In one embodiment, the determination of step 250 effectively
determines a level of confidence in whether the mobile device is
inside a building, which permits the estimated position to be
located within an amount of tolerated error from the building even
if the estimated position is located outside the building. If the
confidence is low (e.g., if the estimated position is not inside
the building, if the estimated position is not within an amount of
tolerated error from the building, or if the amount of a location
confidence area overlapping the building is not more than a
threshold amount), then the default determination is that the
mobile device is more likely to be in a vehicle near the building
than in the building. If a mobile device enters a vehicle parked
next to a building, and the confidence that the mobile device is in
the building is high (e.g., if the estimated position is inside the
building, if the estimated position is within an amount of
tolerated error from the building, or if the amount of a location
confidence area overlapping the building is more than a threshold
amount), a determination that the mobile device is in the building
may be later modified to a determination that the mobile device was
in a vehicle once additional estimated positions of the mobile
device indicate the vehicle is moving away from the building, or
once measurements from an inertial sensor indicate movement akin to
vehicle movement. As an extreme example, if subsequent estimated
positions of the mobile device or if inertial sensors of the mobile
device indicate a pace of travel by the mobile device that is
unlikely to be possible by a human walking, and is more likely to
be caused by a moving vehicle, then the determination may be
changed from the mobile device being in a building to being in a
vehicle.
[0040] In one embodiment of FIG. 2, an optional step (not shown)
may be performed before step 260a is performed. In the optional
step, a determination is made if the mobile device has been moving
at a speed or acceleration that is assumed to be not possible
inside a building (e.g., a speed or acceleration exceeding a
threshold walking speed or acceleration). If the mobile device has
been moving at a speed or acceleration that is assumed to be not
possible inside a building, then step 260a is not performed, and
instead step 260b is performed (i.e., the determination is that the
mobile device is located in a vehicle, not the building).
Alternatively, this optional step may occur after step 240, but
before step 250, and the result would be proceeding to step 260b
without performing step 250 if the mobile device has been moving at
a speed or acceleration that is assumed to be not possible inside a
building, and otherwise performing step 250 if the mobile device
has been moving at a speed or acceleration that is assumed to be
possible inside a building.
[0041] In optional step 270, additional operations are performed
based on where the mobile device is determined to be located.
Examples of additional operations during step 270 include using
knowledge of the mobile device's location as being inside a
building or inside a vehicle to: (i) identify information about the
building (e.g, a map of the building, predetermined HVAC
characteristics) or information about the vehicle (e.g.,
predetermined HVAC characteristics); (ii) determine when to
calibrate a pressure sensor of the mobile device (e.g., when the
mobile device is not inside the building or the vehicle, or when
pressure measurements by the mobile device when the mobile device
is inside the building or the vehicle can be adjusted to account
for HVAC effect of the building or the vehicle); (iii) determine
when to measure HVAC characteristics of the building (e.g., to
collect data during a time period while the mobile device is inside
the building for use in modifying stored HVAC characteristics of
the building, for use in determining energy efficiency of the
building's HVAC system, or other purposes); (iv) determine when the
mobile device is outside a building, but inside a vehicle's
environment that may be causing a measurement of pressure that does
not accurately reflect pressure outside of the vehicle.
Detecting a Change in Pressure Measured by a Mobile Device that
Meets or Exceeds a Threshold Value of Change (Step 210)
[0042] One embodiment of step 210 is shown in FIG. 3A, which
includes the steps of: collecting a plurality of pressure
measurements using a pressure sensor of the mobile device during
the Nth predefined time period (step 311a); determining, based on
the plurality of pressure measurements, a range of pressures that
were measured during the Nth predefined time period (step 313a);
determining if the range of pressure meets or exceeds a threshold
pressure range value (step 315a); if the range of pressure meets or
exceeds the threshold pressure range value, determining that the
change in pressure measured by the mobile device during the Nth
predefined time period meets or exceeds the threshold value of
change (step 317a); and if the range of pressure does not meet or
exceed the threshold pressure range value, increment N by 1, and
return to step 311a. An example of a threshold pressure range value
includes 20 Pa. One advantage of the process shown in FIG. 3A over
other processes shown in other figures includes minimizing memory
use and processing used for computations, where use of the process
need only track and store a minimum pressure measurement and a
maximum pressure measurement in addition to the timestamps of those
measurements. Any new measurements need only be checked against the
minimum pressure measurement and the maximum pressure measurement
to determine if either should be replaced by the new measurement.
As a result, only up to three sets of measurements need to be
stored at a time (e.g., the minimum, maximum and current
measurements).
[0043] Another embodiment of step 210 is shown in FIG. 3B, which
includes the steps of: collecting a plurality of pressure
measurements using a pressure sensor of the mobile device during
the Nth predefined time period (step 311b); determining, based on
the plurality of pressure measurements, a distribution (e.g.,
standard deviation) of the pressure measurements that were measured
during the Nth predefined time period (e.g., 68%, 80%, 90%, or
other) (step 313b); determining if the distribution (e.g., standard
deviation) meets or exceeds a threshold standard deviation value
(step 315b); if the distribution (e.g., standard deviation) meets
or exceeds the threshold distribution (e.g., standard deviation)
value, determining that the change in pressure measured by the
mobile device during the Nth predefined time period meets or
exceeds the threshold value of change (step 317b); and if the
distribution (e.g., standard deviation) does not meet or exceed the
threshold pressure range value, increment N by 1, and return to
step 311b. An example of a threshold distribution (e.g., standard
deviation) value includes 10 Pa. One advantage of the process shown
in FIG. 3B over other processes shown in other figures includes
being able to distinguish a sudden change in measured pressure from
random fluctuations that could be attributed to sensor noise or
atmospheric turbulence.
[0044] The process shown in FIG. 3B can be modified to use variance
instead of standard deviation, where variance is the standard
deviation, squared. One advantage of using variance includes
simplified computation by not needing to apply a square root to the
formula, since standard deviation requires once summing the
differences between each value and the mean before dividing by the
number of data points, which can be cumbersome for low-level
firmware programming without some approximations (e.g., Taylor
series).
[0045] Another embodiment of step 210 is shown in FIG. 3C, which
includes the steps of: collecting a plurality of pressure
measurements using a pressure sensor of the mobile device during
the Nth predefined time period (step 311c); determining, based on
the plurality of pressure measurements, a range of pressures that
were measured during the Nth predefined time period (step 313c);
determining, based on the plurality of pressure measurements, a
standard deviation of the pressure measurements that were measured
during the Nth predefined time period (step 314c); determining if
the range of pressure meets or exceeds a threshold pressure range
value, or if the standard deviation meets or exceeds a threshold
standard deviation value (step 315c); if the range of pressure
meets or exceeds the threshold pressure range value, or if the
standard deviation meets or exceeds the threshold standard
deviation value, determining that the change in pressure measured
by the mobile device during the Nth predefined time period meets or
exceeds the threshold value of change (step 317c); and if both the
range of pressure does not meet or exceed the threshold pressure
range value and the standard deviation does not meet or exceed the
threshold standard deviation value, increment N by 1, and return to
step 311c. One advantage of the process shown in FIG. 3C over other
processes shown in other figures includes having more ways of
detecting a threshold change in pressure.
[0046] Yet another embodiment of step 210 is shown in FIG. 3D,
which includes the steps of: collecting two pressure measurements
using a pressure sensor of the mobile device during the Nth
predefined time period (step 311d); determining a difference in
pressure between the two pressure measurements (step 313d);
determining if the difference in pressure between the two pressure
measurements meets or exceeds a threshold pressure difference value
(step 315d); if the difference in pressure meets or exceeds the
threshold pressure difference value, determining that the change in
pressure measured by the mobile device during the Nth predefined
time period meets or exceeds the threshold value of change (step
317d); and if the difference in pressure does not meet or exceed
the threshold pressure range value, increment N by 1, and return to
step 311d. One advantage of the process shown in FIG. 3D over other
processes shown in other figures includes reduced memory usage
since only two pressure measurement values need to be stored.
[0047] By way of example, some embodiments of each of FIG. 2, FIG.
3A, FIG. 3B, FIG. 3C and FIG. 3D use a moving time window that
checks for pressure changes after each new pressure measurement is
added. These embodiments may also account for natural pressure
variation by imposing a maximum time limit between consecutive
pressure measurements that are considered in the range, standard
deviation, or other tests--e.g., where only a series of two or more
pressure measurements with separations between consecutive pressure
measurements that all meet the requirement for the maximum time
limit is considered in the range, standard deviation, or other
computations. As a result, short term changes on the order of
minutes are monitored.
[0048] By way of example, the processes of FIG. 2, FIG. 3A, FIG.
3B, FIG. 3C and FIG. 3D may be performed by one or more machines
that include: processor(s) or other computing device(s) (e.g., at a
mobile device and/or a server) for performing (e.g., that perform,
or are configured, adapted or operable to perform) each step; data
source(s) at which any data identified in the processes is stored
for later access during the processes; and a pressure sensor of the
mobile device.
Determining when a Mobile Device is Expected to be Inside or
Outside a Building
[0049] FIG. 5A and FIG. 5B illustrate an approach for determining
when a mobile device is expected to be inside or outside a
building. As shown in FIG. 5A, a location confidence area falls
entirely within a building's polygon. This illustration represents
circumstances when the overlap of the polygon and the location
confidence area (e.g., 100%) is above a threshold amount of overlap
(e.g., 50%), and a conclusion is made that the mobile device is
inside the building with high confidence. As shown in FIG. 5B, a
location confidence area falls partially within the building's
polygon. This illustration represents circumstances when the
overlap of the polygon and the location confidence area (e.g., 30%)
is below the threshold amount of overlap (e.g., 50%), and a
conclusion is made that the mobile device is either (i) not inside
the building or (ii) inside the building with low confidence given
that the overlap of the polygon and the location confidence area is
below the threshold amount of overlap.
Determining when a Mobile Device is Expected to be Inside an
Environment with a Recognizable Pressure Variation Effect
[0050] Approaches described herein that make determinations based
on whether an HVAC effect is present in an environment can be used
to make similar decisions based on whether other pressure variation
effects (e.g., Venturi effect) are present, as detected from
pressure profiles that are expected for the other pressure
variation effects. For example, if a measured pressure profile has
a particular noise profile (e.g., associated with a Venturi effect
that can be generated by a moving vehicle), a determination can be
made that the mobile device is in an environment where pressure
measurements are unreliable (e.g., the mobile device is inside a
moving vehicle).
Comparison to Other Technologies
[0051] A 2014 paper entitled Using Mobile Phone Barometer for
Low-Power Transportation Context Detection, by Sankaran,
Proceedings of the 12th ACM Conference on Embedded Network Sensor
Systems, Nov. 3-6, 2014, Memphis, Tenn., illustrates a method of
using a barometer to detect if a user is "still", "walking", or
"driving". Depending on the spread of the sensor measurements over
short times, and the measure of the terrain, it appears to assign
an appropriate context mode. Sample thresholds disclosed in the
paper appear to include: if the barometer changes by more than 0.8
m in 5 seconds, the user is "driving"; if the peaks and valleys of
a person's height profile is more than 1 peak per 200 s, the user
is "driving"; if the user has a 0.3 m standard deviation over 200
seconds, the user is flagged as "walking"; otherwise, the user is
"idle". The paper also describes a barometer/accelerometer fusion
technique. By contrast the approaches described in this application
can be used to determine a "building pressure variation effect"
(HVAC) mode and a "vehicle pressure variation effect" (e.g., HVAC,
Venturi) mode that can be used to constrain and improve location
data from other location services for reverse geocoding,
inside/outside detection, or dead reckoning.
Technical Benefits
[0052] Processes described herein improve the fields of calibration
and location determination by determining when measured pressure
conditions are indicative of circumstances during which estimating
an altitude of a mobile device or calibrating a pressure sensor of
the mobile device will be unsuitable without compensating for the
pressure conditions in the estimation process or calibration
process. The processes create new and useful data, including data
that confirms whether circumstances are suitable for putting an
estimated altitude or pressure measurement to use during
calibration of a pressure sensor or estimation of a position of a
mobile device. Prior approaches that do not produce this data prior
to calibration or position determination are more likely to
calibrate or estimate positions with less or even unacceptable
accuracy. Even under conditions where an estimated altitude is not
computed when a mobile device is determined to be inside a
building, the processes described herein that detect when the
mobile device is inside the building advantageously provide
information that has many uses (e.g., to identify a map of the
building, to trigger collection of information about the building,
to resolve possible locations of the mobile device to only
locations that are inside a building, or another use).
Other Aspects
[0053] Any method (also referred to as a "process" or an
"approach") described or otherwise enabled by disclosure herein may
be implemented by hardware components (e.g., machines), software
modules (e.g., stored in machine-readable media), or a combination
thereof. By way of example, machines may include one or more
computing device(s), processor(s), controller(s), integrated
circuit(s), chip(s), system(s) on a chip, server(s), programmable
logic device(s), field programmable gate array(s), electronic
device(s), special purpose circuitry, and/or other suitable
device(s) described herein or otherwise known in the art. One or
more non-transitory machine-readable media embodying program
instructions that, when executed by one or more machines, cause the
one or more machines to perform or implement operations comprising
the steps of any of the methods described herein are contemplated
herein. As used herein, machine-readable media includes all forms
of machine-readable media (e.g. one or more non-volatile or
volatile storage media, removable or non-removable media,
integrated circuit media, magnetic storage media, optical storage
media, or any other storage media, including RAM, ROM, and EEPROM)
that may be patented under the laws of the jurisdiction in which
this application is filed, but does not include machine-readable
media that cannot be patented under the laws of the jurisdiction in
which this application is filed. Systems that include one or more
machines and one or more non-transitory machine-readable media are
also contemplated herein. One or more machines that perform or
implement, or are configured, operable or adapted to perform or
implement operations comprising the steps of any methods described
herein are also contemplated herein. Method steps described herein
may be order independent and can be performed in parallel or in an
order different from that described if possible to do so. Different
method steps described herein can be combined to form any number of
methods, as would be understood by one of ordinary skill in the
art. Any method step or feature disclosed herein may be omitted
from a claim for any reason. Certain well-known structures and
devices are not shown in figures to avoid obscuring the concepts of
the present disclosure. When two things are "coupled to" each
other, those two things may be directly connected together, or
separated by one or more intervening things. Where no lines or
intervening things connect two particular things, coupling of those
things is contemplated in at least one embodiment unless otherwise
stated. Where an output of one thing and an input of another thing
are coupled to each other, information sent from the output is
received in its outputted form or a modified version thereof by the
input even if the information passes through one or more
intermediate things. Any known communication pathways and protocols
may be used to transmit information (e.g., data, commands, signals,
bits, symbols, chips, and the like) disclosed herein unless
otherwise stated. The words comprise, comprising, include,
including and the like are to be construed in an inclusive sense
(i.e., not limited to) as opposed to an exclusive sense (i.e.,
consisting only of). Words using the singular or plural number also
include the plural or singular number, respectively, unless
otherwise stated. The word "or" and the word "and" as used in the
Detailed Description cover any of the items and all of the items in
a list unless otherwise stated. The words some, any and at least
one refer to one or more. The terms may or can are used herein to
indicate an example, not a requirement--e.g., a thing that may or
can perform an operation, or may or can have a characteristic, need
not perform that operation or have that characteristic in each
embodiment, but that thing performs that operation or has that
characteristic in at least one embodiment. Unless an alternative
approach is described, access to data from a source of data may be
achieved using known techniques (e.g., requesting component
requests the data from the source via a query or other known
approach, the source searches for and locates the data, and the
source collects and transmits the data to the requesting component,
or other known techniques).
[0054] FIG. 6 illustrates components of a transmitter, a mobile
device, and a server. Examples of communication pathways are shown
by arrows between components.
[0055] By way of example in FIG. 6, each of the transmitters may
include: a mobile device interface 11 for exchanging information
with a mobile device (e.g., an antenna and RF front end components
known in the art or otherwise disclosed herein); one or more
processor(s) 12; memory/data source 13 for providing storage and
retrieval of information and/or program instructions; atmospheric
sensor(s) 14 for measuring environmental conditions (e.g.,
pressure, temperature, other) at or near the transmitter; a server
interface 15 for exchanging information with a server (e.g., an
antenna, a network interface, or other); and any other components
known to one of ordinary skill in the art. The memory/data source
13 may include memory storing software modules with executable
instructions, and the processor(s) 12 may perform different actions
by executing the instructions from the modules, including: (i)
performance of part or all of the methods as described herein or
otherwise understood by one of skill in the art as being
performable at the transmitter, (ii) generation of positioning
signals for transmission using a selected time, frequency, code,
and/or phase; (iii) processing of signaling received from the
mobile device or other source; or (iv) other processing as required
by operations described in this disclosure. Signals generated and
transmitted by a transmitter may carry different information that,
once determined by a mobile device or a server, may identify the
following: the transmitter, the transmitter's position;
environmental conditions at or near the transmitter, and/or other
information known in the art. The atmospheric sensor(s) 14 may be
integral with the transmitter, or separate from the transmitter and
either co-located with the transmitter or located in the vicinity
of the transmitter (e.g., within a threshold amount of
distance).
[0056] By way of example FIG. 6, the mobile device may include: a
transmitter interface 21 for exchanging information with a
transmitter (e.g., an antenna and RF front end components known in
the art or otherwise disclosed herein); one or more processor(s)
22; memory/data source 23 for providing storage and retrieval of
information and/or program instructions; atmospheric sensor(s) 24
for measuring environmental conditions (e.g., pressure,
temperature, other) at the mobile device; other sensor(s) 25 for
measuring other conditions (e.g., inertial sensors for measuring
movement and orientation); a user interface 26 (e.g., display,
keyboard, microphone, speaker, other) for permitting a user to
provide inputs and receive outputs; another interface 27 for
exchanging information with the server or other devices external to
the mobile device (e.g., an antenna, a network interface, or
other); and any other components known to one of ordinary skill in
the art. A GNSS interface and processing unit (not shown) are
contemplated, which may be integrated with other components (e.g.,
the interface 21 and the processors 22) or a standalone antenna, RF
front end, and processors dedicated to receiving and processing
GNSS signaling. The memory/data source 23 may include memory
storing software modules with executable instructions, and the
processor(s) 22 may perform different actions by executing the
instructions from the modules, including: (i) performance of part
or all of the methods as described herein or otherwise understood
by one of ordinary skill in the art as being performable at the
mobile device; (ii) estimation of an altitude of the mobile device
based on measurements of pressure form the mobile device and
transmitter(s), temperature measurement(s) from the transmitter(s)
or another source, and any other information needed for the
computation); (iii) processing of received signals to determine
position information (e.g., times of arrival or travel time of the
signals, pseudoranges between the mobile device and transmitters,
transmitter atmospheric conditions, transmitter and/or locations or
other transmitter information); (iv) use of position information to
compute an estimated position of the mobile device; (v)
determination of movement based on measurements from inertial
sensors of the mobile device; (vi) GNSS signal processing; or (vii)
other processing as required by operations described in this
disclosure.
[0057] By way of example FIG. 6, the server may include: a mobile
device interface 21 for exchanging information with a mobile device
(e.g., an antenna, a network interface, or other); one or more
processor(s) 32; memory/data source 33 for providing storage and
retrieval of information and/or program instructions; a transmitter
interface 34 for exchanging information with a transmitter (e.g.,
an antenna, a network interface, or other); and any other
components known to one of ordinary skill in the art. The
memory/data source 33 may include memory storing software modules
with executable instructions, and the processor(s) 32 may perform
different actions by executing instructions from the modules,
including: (i) performance of part or all of the methods as
described herein or otherwise understood by one of ordinary skill
in the art as being performable at the server, (ii) estimation of
an altitude of the mobile device; (iii) computation of an estimated
position of the mobile device; or (iv) other processing as required
by operations described in this disclosure. Steps performed by
servers as described herein may also be performed on other machines
that are remote from a mobile device, including computers of
enterprises or any other suitable machine.
[0058] Systems and methods disclosed herein may operate within a
network of terrestrial transmitters or satellites. The transmitters
may be located at different altitudes or depths that are inside or
outside various natural or manmade structures (e.g. buildings).
Positioning signals may be sent to the mobile device from the
transmitters and/or satellites using known wireless or wired
transmission technologies. The transmitters may transmit the
signals using one or more common multiplexing parameters--e.g. time
slot, pseudorandom sequence, frequency offset, or other. The mobile
device may take different forms, including a mobile phone, a
tablet, a laptop, a tracking tag, a receiver, or another suitable
device that can receive the positioning signals. Certain aspects
disclosed herein relate to positioning modules that estimate the
positions of mobile devices--e.g., where the position is
represented in terms of: latitude, longitude, and/or altitude
coordinates; x, y, and/or z coordinates; angular coordinates; or
other representations. Positioning modules use various techniques
to estimate the position of a mobile device, including
trilateration, which is the process of using geometry to estimate
the position of a mobile device using distances traveled by
different "positioning" (or "ranging") signals that are received by
the mobile device from different beacons (e.g., terrestrial
transmitters and/or satellites). If position information like the
transmission time and reception time of a positioning signal from a
beacon are known, then the difference between those times
multiplied by speed of light would provide an estimate of the
distance traveled by that positioning signal from that beacon to
the mobile device. Different estimated distances corresponding to
different positioning signals from different beacons can be used
along with position information like the locations of those beacons
to estimate the position of the mobile device. Positioning systems
and methods that estimate a position of a mobile device (in terms
of latitude, longitude and/or altitude) based on positioning
signals from beacons (e.g., transmitters, and/or satellites) and/or
atmospheric measurements are described in co-assigned U.S. Pat. No.
8,130,141, issued Mar. 6, 2012, and U.S. Patent Application
Publication No. US 2012/0182180, published Jul. 19, 2012. It is
noted that the term "positioning system" may refer to satellite
systems (e.g., Global Navigation Satellite Systems (GNSS) like GPS,
GLONASS, Galileo, and Compass/Beidou), terrestrial systems, and
hybrid satellite/terrestrial systems.
[0059] This application relates to the following related
application(s): U.S. Pat. Appl. No. 62/676,267, filed 24 May 2018,
entitled SYSTEMS AND METHODS FOR DETERMINING WHETHER A MOBILE
DEVICE IS INSIDE AN ENVIRONMENT EXPERIENCING ADVERSE PRESSURE
VARIATION CONDITIONS; and U.S. Pat. Appl. No. 62/687,735, filed 20
Jun. 2018 entitled SYSTEMS AND METHODS FOR DETERMINING WHETHER A
MOBILE DEVICE IS INSIDE AN ENVIRONMENT EXPERIENCING ADVERSE
PRESSURE VARIATION CONDITIONS. The content of each of the related
application(s) is hereby incorporated by reference herein in its
entirety.
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