HYBRID MOBILE PHONE GEOPOSITIONING
BACKGROUND
[0001] The recovery of the location of a mobile device, such as a cellular telephone
or a smart phone, is the basis for a wide range of Location-Based-Services (LBS). A
Location Based Service is an information service, accessible to mobile devices through the
cellular network utilizing the geographical position of the mobile device. Location based
services can be used in a variety of contexts, such as health, work, personal, and
entertainment by identifying the location of an individual or object using the position of
the mobile device and providing the individual with information regarding various service
providers in the same location as the individual. LBS can include sending advertising
directed at customers based on their location, personalized weather services, locations of
restaurants, gas stations, other businesses, and comparable services.
[0002] Various techniques may be utilized in order to determine the location of a
mobile device, including network based cell tower triangulation, Global Positioning
System (GPS), peer-based systems (e.g. Bluetooth based short range systems), and
Wireless Local Area Networks (WLAN). Network-based techniques, such as cellular
triangulation, utilize the service provider's network infrastructure and temporal delay of
tower signals from nearby cell towers' receptions to identify the location of a mobile
device within a "cell." This method is the most common as it can be implemented cost
effectively and non-intrusively while the mobile device is not actively in use by the user.
However, the accuracy of this technique is relatively low due to its dependence on the
concentration of base station cells, achieving an accuracy of a few tenths of meters in
urban areas, but as poor as hundreds of meters in suburban areas and rural zones.
Accuracy may also vary due to obstacles such as large buildings and weather conditions.
[0003] Using WLANs may apply a similar triangulation method with the WLAN
signal origination spot as the basis for the triangulation cell, or more commonly the
location can be estimated by sensing a single WLAN source, as the WLAN range is
typically limited. This method may be more useful in urban areas, where the relatively
large number of WLAN spots may generate smaller cells relative to cell towers and
increase positional accuracies. However, WLAN spots must be mapped relative to the
world, and their use is dependent on a comprehensive database of WLAN access points.
WLAN points maybe very dynamic, and may be added, removed, turned on and off quite
frequently. Their accuracy may also be reduced due to obstacles and weather. Another
approach using GPS is the most accurate method of locating a mobile device to within 10-
30 meters. However, this approach requires substantial computation power and is energy
expensive, which may rapidly deplete battery power on a mobile device. As a result, GPS
based location determination is commonly used for short intervals or in specific navigation
tasks, and is not continuously activated on most mobile devices. GPS is also difficult to
be sensed in indoor environments.
SUMMARY
[0004] This summary is provided to introduce a selection of concepts in a simplified
form that are further described below in the Detailed Description. This summary is not
intended to exclusively identify key features or essential features of the claimed subject
matter, nor is it intended as an aid in determining the scope of the claimed subject matter.
[0005] Embodiments are directed to a hybrid positioning system for continuously
and accurately determining a location of a mobile device. The hybrid positioning system
may utilize samples of GPS locations from a pool of mobile devices accompanied by cell
tower data, WLAN data, or other comparable network signals to construct a dynamic map
of particular regions. According to some embodiments, the dynamic map may be sent to
and stored on a mobile device. The map may enable the mobile device to compare its less
accurate, but more readily available, data such as cell tower signals to recorded ones and
estimate its position more accurately. The position data may be further enhanced by GPS
data whenever it is available. The mobile device may then send its position to a server for
user in location based services.
[0006] These and other features and advantages will be apparent from a reading of
the following detailed description and a review of the associated drawings. It is to be
understood that both the foregoing general description and the following detailed
description are explanatory and do not restrict aspects as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a diagram illustrating an example of cellular triangulation technique;
[0008] FIG. 2 illustrates an example environment, where various mobile devices
employ different signal sources for determining their locations;
[0009] FIG. 3 illustrates a network, where a location determination service may
receive data from mobile devices connected to cellular towers, WLANs, and/or GPS;
[0010] FIG. 4 is a block diagram of an example mobile device operating
environment and server computing environment, where network communication and
processing of a dynamic map according to embodiments may be implemented;
[0011] FIG. 5 is a conceptual diagram illustrating use of location information from a
plurality of mobile devices in creating a dynamic map to be used for accurate and
continuous location determination by other mobile devices;
[0012] FIG 6. illustrates an example computing device, where embodiments may be
implemented; and
[0013] FIG. 7 illustrates a logic flow diagram for a process of using mobile devices
to gather mobile location data to generate a dynamic map for accurately and continuously
determining locations of other mobile devices.
DETAILED DESCRIPTION
[0014] As briefly described above, mobile location data may be gathered using
mobile devices enabled with Global Positioning Systems (GPS) and their reception of
cellular tower signal information or other wireless signal information, such as WLANs, or
other comparable systems. Such data may then be used to build a continuous and dynamic
map of an area within a cellular network of cellular towers, WLAN origination spots,
other wireless signals and their relation to accurate GPS locations. A system according to
embodiments may utilize other location detection mechanisms as well. For example, short
range signals such as Bluetooth that may mark locations (e.g. stores), location recognition
by matching images, taken by an imaging capable device, audio recognition (e.g. the
sound of a clock tower, ambient noise, etc. may be compared to sounds in a pre-recorded
library), and comparable ones. Any information such as the ones described above may be
added to the location map. In addition, an accelerometer and/or a compass integrated into
the mobile device may also be used to as a location determination source. An accurate
location of any mobile device within an area or landscape may then be determined using
the dynamic map of the landscape and interpolation of points on the map using algorithms
and mapping techniques. In the following detailed description, references are made to the
accompanying drawings that form a part hereof, and in which are shown by way of
illustrations specific embodiments or examples. These aspects may be combined, other
aspects may be utilized, and structural changes may be made without departing from the
spirit or scope of the present disclosure. The following detailed description is therefore
not to be taken in a limiting sense, and the scope of the present invention is defined by the
appended claims and their equivalents.
[0015] While the embodiments will be described in the general context of program
modules that execute in conjunction with an application program that runs on an operating
system on a computing device or mobile device, those skilled in the art will recognize that
aspects may also be implemented in combination with other program modules.
[0016] Generally, program modules include routines, programs, components, data
structures, and other types of structures that perform particular tasks or implement
particular abstract data types. Moreover, those skilled in the art will appreciate that
embodiments may be practiced with other computer system configurations, including
hand-held devices, multiprocessor systems, microprocessor-based or programmable
consumer electronics, minicomputers, mainframe computers, and comparable computing
devices. Embodiments may also be practiced in distributed computing environments
where tasks are performed by remote processing devices that are linked through a
communications network. In a distributed computing environment, program modules may
be located in both local and remote memory storage devices.
[0017] Embodiments may be implemented as a computer-implemented process
(method), a computing system, or as an article of manufacture, such as a computer
program product or computer readable media. The computer program product may be a
computer storage medium readable by a computer system and encoding a computer
program that comprises instructions for causing a computer or computing system to
perform example process(es). The computer-readable storage medium can for example be
implemented via one or more of a volatile computer memory, a non-volatile memory, a
hard drive, a flash drive, a floppy disk, or a compact disk, and comparable media. The
computer program product may also be a propagated signal on a carrier (e.g. a frequency
or phase modulated signal) or medium readable by a computing system and encoding a
computer program of instructions for executing a computer process.
[0018] Throughout this specification, the term "platform" may be a combination of
software and hardware components for using signal information and positioning data to
generate a dynamic map to locate mobile devices in a geographic area. Examples of
platforms include, but are not limited to, a hosted service executed over a plurality of
servers, an application executed on a single server, and comparable systems. The term
"server" refers to a computing device executing one or more software programs typically
in a networked environment. More detail on these technologies and example operations is
provided below.
[0019] Referring to FIG. 1, diagram 100 illustrates an example cellular triangulation
technique for locating a mobile device within a cell. Cellular triangulation uses signal
analysis data to calculate the time it takes signals to travel from a mobile device 104 to at
least three cellular towers (101, 102, and 103). The first tower 101 detects the mobile
device 104 within a certain radius of its signal, and the second tower 102 detects the
mobile device 104 within a certain radius of its signal, and the third tower 103 then detects
the mobile device 104 within a certain radius of its signal. The area where each radius
overlaps is the approximate location of the mobile device. Cellular Triangulation does
not take into account obstacles or impedances such as buildings and weather conditions,
and the accuracy of the mobile device's location is relatively low. Any platform, network,
or computing device may perform the signal analysis, once the mobile device
communicates the signal data to the network or computing device.
[0020] Triangulation is not limited to cellular towers, but can also be used with other
wireless signals such as Wireless Local Area Networks (WLAN), which transmit wireless
signals that are received by mobile devices. Mobile devices can then be detected in an
area in which the mobile device receives signals from at least three different WLANs or
identifiable transmitters (e.g. repeaters) of the same WLAN. Measurement of the signal
strength and computation of the triangulated location may be performed at the mobile
device or at another device coupled to the network as discussed above.
[0021] In FIG. 2, diagram 200 illustrates an example environment, where various
mobile devices employ different signal sources for determining their locations. Of the
mobile devices, some may be enabled to connect to GPS and others to WLANs. All
mobile devices may be connected to cellular network 204. While the example illustration
is focused on cellular network based mobile devices, embodiments are not limited to
those. Indeed, embodiments may be implemented with mobile devices that can utilize any
one of GPS, WLAN, and cellular network signals to determine their location, as well as
various combinations of the three signal sources. Other network types such as Wide Area
Networks (WANs) or short range signals from Personal Area Networks (PANs) or similar
small networks may also be utilized to estimate mobile device locations using the
principles described herein. Furthermore, matching images or audio captured by the
mobile devices, integrated position devices such as accelerometers or compasses may be
employed to enhance location determination. According to further embodiments, mobile
devices may be "tethered". For example, if two acquaintances are near each other, only
one may need to run the geo-location application. The other can "tether" their live
location.
[0022] Mobile device 203 exemplifies the common cellular phone based device in a
network, which only senses and receives signals from cellular towers 205. Thus, the local
position of such devices can only be determined using techniques such as cellular
triangulation. A system according to embodiments relies on comparison of different
location determination techniques for increasing accuracy of techniques such as cellular
triangulation. Therefore, mobile device 203 may be useful to the data collection portion of
the system if it has a secondary method of determining its location (e.g. a stationary device
at a known location). On the other hand, mobile device 203 may utilize an output of the
system, a dynamic map of location based data points including signal information such as
cellular signal values, thereby determining its location accurately based on the cellular
signal readings at the device.
[0023] Mobile device 202 is an example of a mobile device enabled with a satellitebased
positioning system such as a GPS service 201. Mobile devices enabled with GPS
may calculate their precise geographic location of the device using the GPS service 201.
The GPS service 201 calculates the location by timing signals sent by GPS satellites and
communicates the specific position signal to the mobile device 202. Once the mobile
device 202 receives an accurate position signal from GPS, the device may store its
accurate geographical location. Simultaneously, the mobile device 202 receives signals
from the cellular towers 205 and may stores signal strength data from each cellular tower
within its range. Mobile device 202 may communicate via cellular network 204 to a
hosted service 206 or individual server 2 11 and send its precise geographical location
provided by GPS and the signal strength data from cellular towers for processing.
[0024] Mobile device 207 exemplifies a mobile device, which is connected to
various cellular towers 205 via cellular network 204 and also receives signals from WLAN
208. Mobile devices enabled to receive WLAN signals 208 can be used to estimate the
mobile device's position through similar triangulation techniques or other algorithms
where the basis for the triangulation is the WLAN signal location. In addition to
triangulation, mobile device 208 may also determine its location based on an identity of
WLAN 208 if the network is a relatively small one such as a home network or a hot spot.
Once the device receives signal information from WLAN 208, it may communicate this
data to the hosted service 206 or server 2 11, which may use the WLAN based and cellular
triangulation based data to create a data point in the dynamic map of locations.
[0025] Mobile device 209 is a device enabled with GPS 210 and connected to
WLAN 212. Mobile device 209 also receives continuous signals from various cellular
towers 205 and is connected to cellular network 204. Mobile device 209 may report to
hosted service 206 and/or server 2 11 signal strength information associated with cellular
towers 205, WLAN 212, its GPS based location, and any additional position information
signals providing multiple sources of information. The information may then be used to
add a data point to a dynamic map of locations and associated signal strengths / types.
[0026] FIG. 3 illustrates a network, where a location determination service may
receive data from mobile devices connected to cellular towers, WLANs, and/or GPS. As
discussed above, various mobile devices (301 through 307) may collect and report location
information based on different sources. The location information may include
longitude/latitude information provided by a GPS service, signal strength and/or identity
information associated with cellular or data networks, and comparable ones. Some of the
data such as cellular triangulation information may not be as accurate as others, but by
correlating data from different sources, an accuracy of location information for each
device may be increased.
[0027] The information received from mobile devices 301 through 307 at servers 309
via network(s) 310 may be processed to generate a database of locations and
corresponding signal strengths / source identities (e.g. WLAN identity, cell tower
identity). Then, a dynamic map of locations and corresponding signal strengths / source
identities may be created. According to some embodiments, additional data points for the
map may be generated by extrapolating data from existing received data.
[0028] Servers 309 may transmit the map to mobile devices 308, which may use it to
determine their locations accurately and continuously by evaluating signal strengths and
source identities against comparable ones on the map. The map may be a dynamic one
updated as new information from mobile devices 301 through 307 is collected, new
extrapolations performed, and/or old data decays with time (e.g. by weighting). This way,
mobile devices 308 do not have to activate and use energy consuming GPS continuously
to determine their location accurately. Even if mobile devices 308 do not have GPS
capability, they can still determine their location with relatively high accuracy based on
cellular or other network signals. According to other embodiments, the location
determination process may be further enhanced by sporadic GPS readings in devices
equipped with GPS capability (but not continuous use).
[0029] The example systems in FIG. 1 through 3 have been described with specific
servers, mobile devices, networks, and interactions. Embodiments are not limited to
systems according to these example configurations. A network containing various
wireless connections and devices for communication may be implemented in
configurations employing fewer or additional location measuring components and
performing other tasks. Furthermore, specific protocols and/or interfaces may be
implemented in a similar manner using the principles described.
[0030] FIG. 4 is a block diagram of an example mobile device operating
environment and server computing environment, where network communication and
processing of mobile location data to generate a dynamic map according to embodiments
may be implemented. The mobile device operating environment may include a mobile
device 420 connected to cellular service 402, GPS service 401, or wireless networks 403,
which may interact with the mobile device 420 to provide mobile location data and other
services.
[0031] Mobile device 420 may include a mobile location data module 423 for
obtaining data related to a mobile location or geographical position of the mobile device,
such as GPS specific location of the mobile device or the cellular tower signal strength of
surrounding cellular towers, or the signal strength of surrounding WLAN spots. The
mobile device 420 may continuously gather and store mobile location data and signal
strength data and then communicate the mobile location data to server 410 via the cellular
network or another wireless network. Because transmitting information can be energy
costly, the device may send updates when it has access to an accurate location (e.g. GPS)
to update the dynamic map, and occasionally when it does not have access to GPS. A
dynamic mobile location mapping module 413 of server 410 may store and process the
location data to build a dynamic map of mobile locations.
[0032] Mobile device 420 and server 410 may communicate through their respective
communication applications 422 and 412 employing communication hardware interfaces
421 and 411. Server 410 may accumulate mobile location data samples to create a map of
mobile devices within the area and their GPS positions relative to cellular towers and/or
WLANs and signal strengths. As the sampled data points are accumulated by the server
410, dynamic mobile location mapping module 413 may process the samples and add
them to the database to generate a continuous mapping and a dynamic view of the cellular
landscape. Various operational aspects of server 410 may controlled through its user
interface 414.
[0033] Server 410 may also provide the dynamic map to mobile device 420 enabling
it to compare its signal strength information to the data points on the map and accurately
determine its own position even in the absence of accurate location data such as GPS data.
To optimize transmission and storage/processing at the mobile device 420, server 410 may
compress the map prior to transmission using various compression techniques such as
principal component analysis (PCA). Dynamic mobile location mapping module 413 may
also interpolate received data points and extrapolate additional data points based on its
computations. This approach may be especially useful in regions with few data points
(e.g. rural areas with sparse mobile devices) or in regions, where data from cellular
networks or WLANs may be skewed due to geographical impediments, weather
conditions, etc.
[0034] FIG. 5 includes conceptual diagram 500 illustrating use of location
information from a plurality of mobile devices in creating a dynamic map to be used for
accurate and continuous location determination by other mobile devices. As discussed
previously, a framework for enabling accurate and/or continuous location determination of
mobile devices without continuous use of accurate location services such as GPS includes
three main components.
[0035] The first component includes mobile devices 504, which may receive location
information from a variety of sources such as cellular networks 501, GPS service 502,
WLANs 503, and comparable ones. Some of the mobile devices 504 may receive location
information from a single source while others may receive location information from a
combination of two or more sources. Mobile devices 504 may report their location
information (i.e. location from GPS, signal strength and source identity from various cell
towers, signal strength and source identity from various WLANs and their transmitters in
case of WLANs with multiple transmitters) to server 505, which may execute a mapping
application that generates a dynamic mobile location map 506. The map may include data
points reflecting locations and corresponding signal strength / source identity information
for cellular networks and/or WLANs.
[0036] The dynamic mobile location map 506 may be transmitted to a mobile device
507, where the locally maintained map 508 may be used to determine the mobile device's
location accurately by comparing signal strength / source identity information from
cellular networks and/or WLANs. The information detected by the mobile device 507
may be compared to data points and a corresponding location determined. This way,
mobile device 507 may determine its location accurately (and continuously) without
continuous use of a service like GPS. The locally maintained map 508 may be updated
periodically, on demand, or upon changes in the master map at the server 505.
[0037] According to some embodiments measures may be taken to protect privacy of
mobile device users and/or to protect the cellular network from contamination with
malicious input of mobile location data. One such measure may include assigning
identifiers to each mobile device in an anonymous manner such that the identity of the
device cannot be traced back to its user. The cellular network may then keep a record of
the origination of sample points of mobile location data. Input from mobile devices may
be weighted based on their "reputation", e.g. past history of providing truthful or reliable
location information.
[0038] FIG. 6 and the associated discussion are intended to provide a brief, general
description of a suitable computing environment in which embodiments may be
implemented. With reference to FIG. 6, a block diagram of an example computing
operating environment for an application according to embodiments is illustrated, such as
computing device 600. In a basic configuration, computing device 600 may be any
computing device executing an application capable of using mobile location data to
generate a dynamic mobile location map according to embodiments and include at least
one processing unit 602 and system memory 604. Computing device 600 may also
include a plurality of processing units that cooperate in executing programs. Depending
on the exact configuration and type of computing device, the system memory 604 may be
volatile (such as RAM), non-volatile (such as ROM, flash memory, etc.) or some
combination of the two. System memory 604 typically includes an operating system 605
suitable for controlling the operation of the platform, such as the WINDOWS ® operating
systems from MICROSOFT CORPORATION of Redmond, Washington. The system
memory 604 may also include one or more software applications such as program modules
606, application 622, and dynamic mobile location mapping module 624.
[0039] Application 622 may enable the cellular network to accumulate sample
mobile location data from mobile devices 618 users to generate a continuous and dynamic
map of mobile location data. Through the dynamic mobile location mapping module 624,
a continuous map of mobile devices locations and varying cellular tower signal strengths
may be generated in order to provide a map for interpolating the locations of other mobile
devices within the cellular network landscape. The dynamic mobile location mapping
module 624 may continuously accumulate sample points from multiple mobile devices in
the network as they move throughout the network and may dynamically update the data as
it receives new samples. Application 622 and dynamic mobile location mapping module
624 may be separate applications or integrated modules of a hosted service. This basic
configuration is illustrated in FIG. 6 by those components within dashed line 608.
[0040] Computing device 600 may have additional features or functionality. For
example, the computing device 600 may also include additional data storage devices
(removable and/or non-removable) such as, for example, magnetic disks, optical disks, or
tape. Such additional storage is illustrated in FIG. 6 by removable storage 609 and nonremovable
storage 610. Computer readable storage media may include volatile and
nonvolatile, removable and non-removable media implemented in any method or
technology for storage of information, such as computer readable instructions, data
structures, program modules, or other data. System memory 604, removable storage 609
and non-removable storage 610 are all examples of computer readable storage media.
Computer readable storage media includes, but is not limited to, RAM, ROM, EEPROM,
flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or
other optical storage, magnetic tape, magnetic disk storage or other magnetic storage
devices, or any other medium which can be used to store the desired information and
which can be accessed by computing device 600. Any such computer readable storage
media may be part of computing device 600. Computing device 600 may also have input
device(s) 612 such as keyboard, mouse, pen, voice input device, touch input device, and
comparable input devices. Output device(s) 614 such as a display, speakers, printer, and
other types of output devices may also be included. These devices are well known in the
art and need not be discussed at length here.
[0041] Computing device 600 may also contain communication connections 616 that
allow the device to communicate with other devices, such as mobile devices 618 over a
wired or wireless network in a distributed computing environment, a satellite link, a
cellular link, a short range network, and comparable mechanisms. Mobile devices 618
may include cellular phones, smart phones, vehicle mount mobile devices, handheld
computers, and comparable devices. Communication connection(s) 616 is one example of
communication media. Communication media can include therein computer readable
instructions, data structures, program modules, or other data. By way of example, and not
limitation, communication media includes wired media such as a wired network or directwired
connection, and wireless media such as acoustic, RF, infrared and other wireless
media.
[0042] Example embodiments also include methods. These methods can be
implemented in any number of ways, including the structures described in this document.
One such way is by machine operations, of devices of the type described in this document.
[0043] Another optional way is for one or more of the individual operations of the
methods to be performed in conjunction with one or more human operators performing
some. These human operators need not be collocated with each other, but each can be
only with a machine that performs a portion of the program.
[0044] FIG. 7 illustrates a logic flow diagram for process 700 of using mobile
devices to gather mobile location data to generate a dynamic map for accurately and
continuously determining locations of other mobile devices. Process 700 may be
implemented on a server or other computing device.
[0045] Process 700 begins with operation 710, where location data is received from
various mobile devices within a cellular network connected to at least one of Global
Positioning Systems (GPS), Wireless Local Area Networks (WLAN) or cellular towers.
The mobile devices may gather mobile location data from each available source including
specific geographical location data from GPS and varying signal strengths / source
identities from WLANs and/or cellular towers. At operation 720, a dynamic map may be
created based on the received location data. The map may include locations and
corresponding signal strength / source identity information. The map may further include
extrapolated data points based on received ones.
[0046] At operation 730, the map may be provided to a mobile device by the server.
For optimization of transmission and storage at the mobile device, the map may be
compressed using a variety of compression techniques. At operation 740, the mobile
device may be enabled to determine its location by comparing a signal strength and source
identity for the signal to one or more corresponding ones on the map allowing the mobile
device to determine its location accurately and continuously without having accurate
location data such as GPS data. At operation 750, the location information may be
received from the mobile device and a location based service provided to the mobile
device at optional operation 760 based on the received location information.
[0047] The operations included in process 700 are for illustration purposes.
Gathering mobile location information, communicating mobile location information,
generating mobile location maps and interpreting the maps for location based services may
be implemented by similar processes with fewer or additional steps, as well as in different
order of operations using the principles described herein.
[0048] The above specification, examples and data provide a complete description of
the manufacture and use of the composition of the embodiments. Although the subject
matter has been described in language specific to structural features and/or methodological
acts, it is to be understood that the subject matter defined in the appended claims is not
necessarily limited to the specific features or acts described above. Rather, the specific
features and acts described above are disclosed as example forms of implementing the
claims and embodiments.
CLAIMS
WHAT IS CLAIMED IS:
1. A method executed at least in part in a computing device for determining
accurate location of a mobile device, the method comprising:
receiving mobile location data associated with a plurality of mobile
devices;
creating a dynamic map of mobile device locations within a cellular
network region, wherein the map includes one or more distinct signal types for each
location;
transmitting the map to a mobile device; and
enabling accurate estimation of the mobile device's location by comparison
of at least one of the distinct signal types to a current signal received by the mobile device
at its current location employing the data in the map.
2. The method of claim 1, further comprising:
receiving estimated location data from the mobile device; and
providing a location based service to a user of the mobile device based on
the estimated location.
3. The method of claim 1, wherein creating the dynamic map includes:
creating a database of mobile location data comparing distinct signal types
for each location.
4. The method of claim 3, wherein the distinct signal types include Global
Positioning System (GPS) data, cell tower triangulation data, and Wireless Local Area
Network (WLAN) location data.
5. The method of claim 1, further comprising:
enabling the plurality of mobile devices to transmit their mobile location
data automatically.
6. The method of claim 5, further comprising:
dynamically updating the map; and
transmitting dynamic updates to the mobile device such that a location of
the mobile device is continuously determined.
7. The method of claim 1, further comprising:
assigning identifiers to each of the plurality of mobile devices; and
accepting mobile location data from a select group of mobile devices.
8. The method of claim 10, wherein the select group of mobile devices
includes mobile devices with a trusted history of providing reliable information.
9. A system for determining accurate location of a mobile device, the system
comprising:
a first server configured to:
receive mobile location data based on Global Positioning
System (GPS) and at least one of a cell tower triangulation signal and a
Wireless Local Area Network (WLAN) signal from a plurality of
mobile devices;
create a dynamic database of mobile location data that includes
GPS based locations and corresponding one of the cell tower
triangulation and WLAN signals;
create a plurality of dynamic maps for distinct regions based on
the dynamic database;
in response to receiving a GPS based location from a mobile
device, transmit a map corresponding to the mobile device's location;
and
enable continuous estimation of the mobile device's location by
comparison of one of the cell tower triangulation and WLAN signals to
corresponding data points on the map at the mobile device.
10. The system of claim 9, further comprising:
a second server configured to:
receive the estimated location of the mobile device; and
provide a location based service based on the estimated location.
11. The system of claim 9, wherein the first server is further configured to:
create the map by extrapolating additional data points based on
value pairs of GPS locations and one of cell tower triangulation and
WLAN signals received from the plurality of mobile devices.
12. The system of claim 9, wherein the mobile device is one of: a cellular
phone, a smart phone, a handheld computer, and a vehicle mount computer.
13. A computer-readable storage medium with instructions stored thereon for
determining accurate location of a mobile device, the instructions comprising:
enabling a plurality of mobile devices to collect mobile location data based
on Global Positioning System (GPS) and at least one of a cell tower triangulation signal
and a Wireless Local Area Network (WLAN);
receiving the mobile location data from the plurality of mobile devices;
creating a plurality of dynamic maps of mobile location data, wherein the
maps include data points of received GPS based locations and corresponding one of the
cell tower triangulation and WLAN signals;
extrapolating additional data points based on value pairs of GPS locations
and one of cell tower triangulation and WLAN signals received from the plurality of
mobile devices;
compressing the map;
transmitting the compressed map to a mobile device; and
enabling continuous estimation of the mobile device's location by
comparison of one of the cell tower triangulation and WLAN signals to corresponding
data points on the map at the mobile device.
14. The computer-readable storage medium of claim 13, wherein the
instructions further comprise:
assigning an identifier to each of the plurality of mobile devices 308 for
tracking an origination of sample points of mobile location data.
15. The computer-readable storage medium of claim 13, wherein the identifiers
are assigned in an anonymous manner such that a privacy of mobile device users is
protected.