Method and apparatus to confirm mobile equipment has remained relatively stationary using one or more pilot signal

• US 8,639,262 B2
• Filed: 10/31/2008
• Issued: 01/28/2014
• Est. Priority Date: 10/31/2008
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Holcman, Alejandro R.
• Primary Examiner(s): Kim, Wesley
• Assistant Examiner(s): NGUYEN, DINH
• Application Number:
  US12/262,923
• Publication Number:
  US 20100113061A1
• Time in Patent Office: 1,915 Days
• Field of Search: 455/440, 455/456.1, 455/456.2, 455/456.5, 455/456.6, 455/404.2, 455/456.3, 455/513, 370/332
• US Class Current: 455/456.1
• CPC Class Codes: G01S 19/34 Power consumption
• CPC Class Codes: G01S 5/02521 using a radio-map
• CPC Class Codes: G01S 5/02524 Creating or updating the radio-map

Abstract

A tracking unit operably coupled to mobile equipment is provided. The tracking unit is capable of using a pilot channel for CDMA networks, a broadcast channel for GSM networks or the like, to determine that the tracking unit has remained relatively stationary. The tracking unit determines it has remained relatively stationary by determining that it is receiving the same radio frequency signals at approximately the same strength as it previously received.

Claims

1. A method of using received radio frequency signals to determine whether a mobile equipment has remained relatively stationary, the method comprising:

storing a first strength of at least one of a plurality of pilot channel signals in a first radio frequency signal previously received by a tracking unit of the mobile equipment, wherein the plurality of pilot channel signals are broadcast by a plurality of base stations, the first strength is stored based at least on an associated pilot Pseudo Noise (PN) and detected pilot strength corresponding to the at least one of a plurality of pilot channel signals, and the first strength comprises a previous minimum signal strength and a previous maximum signal strength;

subsequently receiving at the mobile equipment a second radio frequency signal;

calculating a second strength of at least one of the plurality of pilot channel signals in the subsequently received second radio frequency signal;

comparing the second strength to the first strength based on the associated pilot PN;

upon detecting that the second strength is no less than a first amount below the previous minimum signal and no more than a second amount above the previous maximum signal, determining that the mobile equipment has been relatively stationary without performing a location determination;

obtaining an actual position of the mobile equipment; and

adjusting the first amount and the second amount based on the actual position in connection with a movement area.

2. The method of claim 1, wherein the first amount is equal to the second amount.

3. The method of claim 1, wherein the first strength comprises a previous pilot strength and the second strength comprises a current pilot strength.

4. The method of claim 3, further comprising:

storing a first pilot Pseudo Noise (PN) associated with the previous pilot strength;

determining a second pilot PN associated with the current pilot strength; and

comparing the first pilot PN to the second pilot PN to determine that the mobile equipment has remained relatively stationary when the first pilot PN equals the second pilot PN.

5. The method of claim 4, wherein the first pilot PN comprises a plurality of first pilot PNs and the second pilot PN comprises a plurality of second pilot PNs.

6. The method of claim 1 wherein the radio frequency signal comprises at least one of a broadcast channel of a Global System for Mobile Communications (GSM) network or a common pilot channel of an Universal Mobile Telecommunication System (UMTS) network.

7. The method of claim 1, further comprising calculating the first strength averaging previously recorded strengths to define an average strength.

8. The method of claim 7, wherein the average strength is a weighted average.

27. The method of claim 1, wherein the first amount and the second amount at least determine an allowable variation range of the movement area for the mobile equipment.

28. The method of claim 1, wherein the adjusting comprises:

calculating a third strength of a subsequently received radio frequency signal comprising the plurality of pilot channel signals; and

associating the third strength with latitudes and longitudes of a plurality of determined locations near a perimeter of the movement area.

9. A method of using received radio frequency signals to determine whether a mobile equipment has remained relatively stationary, the method comprising:

receiving at the mobile equipment at least one repetitive radio frequency signal comprising a plurality of pilot channel signals broadcast by a plurality of base stations;

establishing a database comprising information of previously received repetitive radio frequency signals received at the mobile equipment, the information comprising an identifier for each previously received repetitive radio frequency signal and a strength for each previously received repetitive radio frequency signal, the strength comprising a previous minimum signal strength and a previous maximum signal strength, and each pilot channel signal being saved based at least on the identifier and the strength;

comparing information of a currently received repetitive radio frequency signal to information in the database of previously received repetitive radio frequency signals including;

upon detecting that the currently received repetitive radio frequency signal is no less than a first amount below the previous minimum signal and no more than a second amount above the previous maximum signal of each of the previously received repetitive radio frequency signals, determining that the mobile equipment has been relatively stationary without performing a location determination,

obtaining an actual position of the mobile equipment, and

adjusting the first amount and the second amount based on the actual position in connection with a movement area; and

updating the information in the database with the information from the currently received repetitive radio frequency signal.

10. The method of claim 9 wherein the identifier is a pilot PN and the strength is a pilot strength.

11. The method of claim 10, wherein the information in the database comprises the time of day that the pilot PN and the pilot strength are determined such that the comparison compares information from approximately the same time of day.

12. The method of claim 10, wherein the establishing the database comprises extracting from the received repetitive radio frequency signal the identifier of each pilot channel signal and calculating the strength of each pilot channel signal.

13. The method of claim 12, wherein the updating comprises averaging the information from the previously received repetitive radio frequency signals with the currently received repetitive radio frequency signal.

14. The method of claim 9, wherein the updating the information comprising comparing the currently received repetitive radio frequency signal with the previous minimum signal strength of each of the previously received repetitive radio frequency signals and replacing the previous minimum signal strength of each of the previously received repetitive radio frequency signals with the currently received repetitive radio frequency signal.

15. The method of claim 9, wherein the updating the information comprising comparing the currently received repetitive radio frequency signal with the previous maximum signal strength of each of the previously received repetitive radio frequency signals and replacing the previous maximum signal strength of each of the previously received repetitive radio frequency signals with the currently received repetitive radio frequency signal.

16. The method of claim 9 wherein the information includes at least one position determination for the previously received repetitive radio frequency signals.

29. The method of claim 9, wherein the first amount and the second amount at least determine an allowable variation range of the movement area for the mobile equipment.

30. The method of claim 9, wherein the adjusting comprises:

calculating a signal strength of the currently received repetitive radio frequency signal comprising the plurality of pilot channel signals; and

associating the signal strength with latitudes and longitudes of a plurality of determined locations near a perimeter of the movement area.

17. A tracking unit operably coupled to a mobile equipment to determine whether the mobile equipment has been relatively stationary, comprising:

a wireless receiver operable to receive current radio frequency transmissions comprising a plurality of pilot channel signals broadcast by a plurality of base stations;

a controller operably coupled to the wireless receiver to extract information from the current radio frequency transmissions, the information comprising an identifier for each of the radio frequency transmissions and a strength for each of the radio frequency transmissions, the strength comprising a previous minimum signal strength and a previous maximum signal strength; and

a memory to store the information of previously received radio frequency transmissions, each pilot channel signal being saved based at least on the identifier and the strength,

wherein the controller is operable to compare the information of the current radio frequency transmissions to the previously received radio frequency transmissions including;

upon detecting that each of the current radio frequency transmissions is no less than a first amount below the previous minimum signal and no more than a second amount above the previous maximum signal of each of the previously received radio frequency transmissions, determining that the mobile equipment has been relatively stationary without performing a location determination,

obtaining an actual position of the mobile equipment, and

adjusting the first amount and the second amount based on the actual position in connection with a movement area.

18. The tracking unit of claim 17, wherein the identifier comprises a pilot PN, and the strength is pilot strength, and the controller extracts the pilot PN and the pilot strength from the pilot channel transmissions and stores the pilot PN and the pilot strength as the information.

19. The tracking unit of claim 17 wherein the wireless receiver receives at least one of broadcast channels from base stations operating under GSM or common pilot channels from base stations operating under UMTS Network.

20. The tracking unit of claim 17, further comprising a location determination sensor operably coupled to the controller to determine the location of the tracking unit.

21. The tracking unit of claim 20 wherein the location determination sensor is a Global Positioning System (GPS) receiver.

22. The tracking unit of claim 17 wherein the controller is operably coupled to the memory to erase the information if the controller determines the tracking unit moved from a previous location.

23. The tracking unit of claim 17 wherein the controller is operable to determine that the mobile equipment has remained relatively stationary after the memory stores previously received radio frequency transmissions.

24. The tracking unit of claim 17, further comprising a GPS receiver adapted to determine the position of the mobile equipment, and wherein the controller is operable to store the position of the mobile equipment in the memory and adapted to use the position of the mobile equipment to tune the ability to determine whether the mobile equipment has remained relatively stationary.

31. The tracking unit of claim 17, wherein the first amount and the second amount at least determine an allowable variation range of the movement area for the mobile equipment.

32. The tracking unit of claim 17, wherein the adjusting comprises:

calculating signal strengths of the current radio frequency transmissions comprising the plurality of pilot channel signals;

associating the signal strengths with latitudes and longitudes of a plurality of determined locations near a perimeter of the movement area.

25. A computer program product containing computer executable codes stored on a non-transitory computer readable storage medium that cause a computer to:

receive current radio frequency transmissions, wherein the current radio frequency transmissions comprise a plurality of pilot channel signals broadcast by a plurality of base stations;

extract information from the current radio frequency transmissions, the information comprising an identifier for each of the radio frequency transmissions and a strength for each of the plurality of pilot channel signals, the strength comprising a previous minimum signal strength and a previous maximum signal strength; and

store the information of previously received radio frequency transmissions, each pilot channel signal being saved based at least on the identifier and the strength; and

compare the information of the current radio frequency transmissions to the previously received radio frequency transmissions including;

upon detecting that each of the current radio frequency transmissions is no less than a first amount below the previous minimum signal and no more than a second amount above the previous maximum signal of each of the previously received radio frequency transmissions, determining that the mobile equipment has been relatively stationary without performing a location determination,

obtaining an actual position of the mobile equipment, and

adjusting the first amount and the second amount based on the actual position in connection with a movement area.

26. A tracking unit to receive radio frequency signals to determine whether a mobile equipment has remained relatively stationary, the tracking unit comprising:

means for storing a first strength of at least one of a plurality of pilot channel signals in a first radio frequency signal previously received by a tracking unit of the mobile equipment, wherein the plurality of pilot channel signals are broadcast by a plurality of base stations, the first strength is stored based at least on an associated pilot Pseudo Noise (PN) and detected pilot strength corresponding to the at least one of a plurality of pilot channel signals, and the first strength comprises a previous minimum signal strength and a previous maximum signal strength;

means for receiving at the mobile equipment a second radio frequency signal;

means for calculating a second strength of at least one of the plurality of pilot channel signals in the subsequently received second radio frequency signal;

means for comparing the second strength to the first strength based on the associated pilot PN;

means for, upon detecting that the second strength is no less than a first amount below the previous minimum signal and no more than a second amount above the previous maximum signal, determining that the mobile equipment has been relatively stationary without performing a location determination;

means for obtaining an actual position of the mobile equipment; and

means for adjusting the first amount and the second amount based on the actual position in connection with a movement area.