METHOD AND SYSTEM FOR DETERMINING THE POSITION OF A MOBILE DEVICE

• US 20100309051A1
• Filed: 08/06/2010
• Published: 12/09/2010
• Est. Priority Date: 03/31/2008
• Status: Active Grant

• Current Assignee: Golba LLC
• Original Assignee: Golba LLC
• Inventors: Moshfeghi, Mehran
• Granted Patent: US 8,314,736 B2
• Time in Patent Office: Days
• US Class Current: 342/378
• CPC Class Codes: G01S 5/0236 Assistance data, e.g. base station almanac
• CPC Class Codes: G01S 5/02521 using a radio-map
• CPC Class Codes: G01S 5/0273 using multipath or indirect path propagation signals in position determination
• CPC Class Codes: H04W 4/027 using movement velocity, acceleration information
• CPC Class Codes: H04W 4/029 Location-based management or tracking services
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 64/006 with additional information processing, e.g. for direction or speed determination

Abstract

Some embodiments use scanning devices to characterize radio signals received at a number of locations within a geographical area of interest. The signal characteristics along with the location information associated with the characteristics are stored in a centralized reference database. A mobile device characterizes signals it receives at a certain location and compares the characteristics with the signal characteristics stored in the reference database to obtain accurate location information of the certain location.

Claims

1. A method of determining a location of a mobile device, the method comprising:

receiving a first plurality of signals with known transmission patterns at the mobile device from a set of transmitters, the first plurality of signals comprising at least one multipath signal;

computing a first set of parameters from the first plurality of signals using the known transmission pattern;

retrieving, from a database, a second set of parameters computed from a second plurality of signals, the second plurality of signals comprising at least one multipath signal, each parameter associated with a location where a corresponding signal from the second plurality of signals was received; and

comparing the first set of parameters with the second set of parameters; and

determining the location of the mobile device based on the comparison.

2. The method of claim 1, wherein a plurality of transmitters in the set of transmitters transmit over a particular transmission channel, wherein the first and second sets of parameters comprise a plurality of parameters characterizing the transmission channel, wherein the first and second sets of parameters comprise channel multipath profile and channel fast Fourier transform (FFT) coefficients.

3. The method of claim 1, wherein the mobile device is moving, the method further comprising:

calculating a velocity of the mobile device; and

revising the determined position of the mobile device based on the velocity of the mobile device and a plurality of previously determined locations of the mobile device.

4. The method of claim 3, wherein the parameters in the first and second sets of parameters comprise a Doppler shift, wherein determining the location of the mobile device comprises utilizing the Doppler shift.

5. The method of claim 1, wherein the first and second sets of parameters comprise time of arrival delay extracted using received signal strength indicator (RSSI) transition, time of arrival delay extracted using signal preamble correlation, time difference of arrival, transmitter signal strength, angle of arrival, and equalizer filter coefficients.

6. The method of claim 1, wherein at least one signal comprises a set of pilot tones, wherein the first and second sets of parameters comprise phase and amplitude of each pilot tone.

7. The method of claim 1 further comprising:

determining an estimated location of the mobile device prior to determining the mobile location; and

limiting the second set of parameters to parameters associated with locations in a vicinity of the estimated location of the mobile device.

8. The method of claim 7, wherein determining the estimated location of the mobile device comprises using a set of previously determined locations of the mobile device.

9. The method of claim 7, wherein each transmitter transmits an identification, wherein each parameter in the database is associated with an identification of a transmitter, wherein retrieving the second set of parameters comprises retrieving parameters associated with identifications of the transmitters transmitting the first plurality of signals.

10. The method of claim 1, wherein determining the location of the mobile device does not comprise using a location of a transmitter.

11. The method of claim 1, wherein determining the location of the mobile device does not comprise determining a distance from the mobile device to a transmitter.

12. The method of claim 1, wherein each location associated with a parameter in the second set of parameters is identified by a set of coordinate values, wherein determining the location of the mobile device comprises:

for each particular location associated with a parameter in the second set of parameters;

multiplying each parameter in the first set of parameters with each of a set of parameters in the second set of parameters associated with the particular location; and

summing a result of each multiplication to determine a correlation parameter corresponding the particular location;

normalizing each correlation coefficient; and

computing a set of coordinate values for the location of the mobile device, each coordinate value for the location of the mobile device computed as a weighed average of each normalized correlation coefficient multiplied by a coordinate value in the set of coordinate values corresponding to the second set of parameters.

13. The method of claim 1, wherein each signal has a set of preambles, wherein computing the first set of parameters using the known transmission pattern comprises determining a peak time of arrival for each signal based on the set of signal preambles.

14. The method of claim 13, wherein the mobile device and each transmitter operate using a clock, wherein the mobile device clock is not synchronized with the transmitter clocks, wherein the transmitters clocks are not synchronized with each other, the method further comprising normalizing the peak time of arrival of each signal to make the peak time of arrival of a first signal received at the mobile device to occur at a time equal to zero.

15. The method of claim 1, wherein the first set of parameters comprises a plurality of different parameter types, the method further comprising:

calculating a location of the mobile device based on each parameter type; and

determining the location of the mobile device as a weighted average of the calculated locations.

16. The method of claim 15, wherein the transmitters transmit signals for a plurality of radio types, each radio type using a different standard, wherein the set of parameters comprises a plurality of parameters computed from signals of one or more of the radio types, the method further comprising:

determining the location of the mobile device for each particular radio type as a weighted average of the calculated locations based on parameters computed from signals of the particular radio type; and

determining the location of the mobile device as a weighted average of the locations determined for each radio type.

17. The method of claim 1, wherein the transmitters transmit signals for a plurality of radio types, each radio type using a different standard, the method further comprising:

calculating a location of the mobile device based on parameters computed from signals of each radio type; and

determining the location of the mobile device as a weighted average of the calculated locations.

18. A method of determining a location of a mobile device, the method comprising:

at a set of scanning devices, receiving a plurality of signals from a plurality of signal sources, the plurality of signals comprising at least one multipath signal;

determining a location where each signal is received by a scanning device;

computing a set of parameters from the received signals;

storing the set of computed parameters and the locations where each signal in a reference database;

receiving a request for parameters to determine the location of the mobile device;

retrieving a set of parameters from the reference database, the set of parameters for comparing with a set of parameters computed from signals received by the mobile device to determine the location of the mobile device.

19. The method of claim 18, wherein a set of signal sources in the plurality of signal source move, wherein the signals received from the moving signal sources vary in time with a known period, the method further comprising:

determining a time when each signal is received by a scanning device;

storing the time each signal is received in the reference database; and

retrieving the time associated with each signal along with the set of parameters retrieved from the database,

wherein determining the location of mobile device comprises;

determining a time when the mobile device received the set of parameters; and

using the time associated with each signal and the time when the mobile device received the set of parameters to revise the location of the mobile device.

20. The method of claim 18, wherein the set of scanning devices comprises one or more moving devices, each moving device comprising a set of antennas for receiving signals.

21. The method of claim 20, wherein one or more of the scanning devices in the set of scanning devices are position enabled, wherein a scanning device is position enabled when the scanning device comprises a set of equipments for determining the scanning device'"'"'s location.

22. The method of claim 18, wherein one or more of the scanning devices in the set of scanning devices are position enabled portable wireless devices, wherein a wireless device is position enabled when the wireless device comprises a set of equipments for determining the wireless device'"'"'s location.

23. The method of claim 18, wherein one or more scanning devices are fixed RF radios with known locations.

24. The method of claim 18, wherein one or more scanning devices comprise more than one antenna for receiving signals, wherein determining the location where each signal is received by a scanning device comprises determining a location where each signal is received by each antenna of a scanning device.

25. The method of claim 18, wherein one or more signal sources in the plurality of signal sources comprise a plurality of antennas for transmitting signals.

26. The method of claim 18 further comprising, updating the set of parameters in the reference database based on the parameters computed from the signals received by the wireless mobile device.

27. A method of determining a location of a mobile device, the method comprising:

receiving a first plurality of signals at the mobile device from a transmitting device over a set of transmission channels, the transmitting device comprising a plurality of antennas, each of the plurality of signals received from one of the antennas of a transmitting device;

characterizing the set of transmission channels to compute a first plurality of parameters associated with the first plurality of signals;

retrieving, from a database, a second plurality of parameters associated with a plurality of signals previously received from the transmitting device by a set of scanning devices;

correlating the first plurality of parameters with the second plurality of parameters; and

determining the location of the mobile device based on the correlation.

28. The method of claim 27, wherein characterizing the set of transmission channels comprises characterizing a profile of the received signals to determine a first plurality of peak time of arrivals associated with the profile of the signals received from the mobile device, wherein the second plurality of parameters comprise a second plurality of peak time of arrivals associated with profiles of a plurality of signals previously received from the transmitting device by the set of scanning devices.

29. The method of claim 28, wherein the mobile device and the transmitting device each operate using a clock, wherein the mobile device clock is not synchronized with the transmitting device clock, the method further comprising normalizing the first plurality of peak time of arrivals to make the peak time of arrival of a first received signal to occur at a time equal to zero.

30. The method of claim 27, wherein the first and second sets of parameters comprise a plurality of parameters characterizing the set of transmission channels, wherein the first and second sets of parameters comprise multichannel profiles and channel fast Fourier transform (FFT) coefficients.

31. The method of claim 27 further comprising receiving one or more multipath signals related to the first plurality of signals, wherein characterizing the profile of the received signals comprises computing a set of parameters for the multipath signals.

32. The method of claim 27, wherein the transmitting device transmits signals of different standards comprising at least two of Wireless Local Area Network (WLAN) 802.11, Bluetooth, WiMax, HD Radio, Ultra-wideband (UWB), GPS, cellular, and 60 GHz standards.

33. The method of claim 27 further comprising receiving signals from a plurality of transmitting devices, wherein the transmitting devices transmit signals of different standards comprising at least two of Wireless Local Area Network (WLAN) 802.11, Bluetooth, WiMax, HD Radio, Ultra-wideband (UWB), GPS, cellular, and 60 GHz standards.

34. The method of claim 27, wherein the mobile device comprises a plurality of antennas for receiving signals, wherein determining the location of the mobile device comprises:

determining a location of each of the plurality of mobile device antennas; and

determining the location of the mobile device based on the locations of the plurality of mobile device antennas.

35. The method of claim 27, wherein each of the plurality of transmitter antennas transmit with an associated preset time delay in relation to other antennas, wherein the mobile device receives signals from each particular transmitter antenna at a particular delay in relation to the signals received from the other transmitter antennas, each particular delay proportional to (i) a distance between the particular antenna and (ii) the preset time delay associated with the antenna.

36. The method of claim 35, wherein the set of transmission channels comprises a plurality of channels, each channel associated with one or more transmitter antenna.

37. The method of claim 27, wherein the plurality of antennas transmit together, wherein the set of transmission channels comprise one transmission channel for all antennas in the plurality of transmitter antennas.