Wireless communication device and system incorporating location-determining means

• US 6,154,656 A
• Filed: 02/27/1997
• Issued: 11/28/2000
• Est. Priority Date: 02/27/1997
• Status: Expired due to Term

• Current Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Camp, William O. Jr.
• Primary Examiner(s): Trost, William G.
• Assistant Examiner(s): GELIN, JEAN ALLAND
• Application Number:
  US08/805,666
• Time in Patent Office: 1,370 Days
• Field of Search: 455/12.1, 455/403, 455/428, 455/430, 455/456, 455/464, 455/521, 455/522, 342/352, 342/357, 342/450, 342/457, 342/463, 370/329, 370/335, 370/465, 370/466, 370/352, 370/328
• US Class Current: 455/456.2
• CPC Class Codes: G01S 19/09 providing processing capability normally carried out by the receiver
• CPC Class Codes: G01S 19/41 Differential correction, e.g. DGPS [differential GPS]
• CPC Class Codes: G01S 2205/008 using a mobile telephone network

Abstract

A device, method and system which enables the location of a wireless communication device to be accurately determined without requiring the device to perform extensive signal processing or calculations. The wireless device frequency-converts a location-determining signal from an initial frequency to the frequency of a standard communication channel, and transmits the frequency-converted signal to a base station in a conventional manner. A location-determining receiver associated with the base station receives the location-determining signal and determines the location of the wireless communication device based on the location-determining signal.

Claims

1. A method for determining a location of a wireless communication device, comprising the steps of:

transmitting a location-determining signal at a first frequency from a location-determining system to the wireless communication device;

switching a transmitter path in the wireless communication device from a first transmitter path, in which the wireless communication device transmits communication signals to one or more control stations at a second frequency, to a second transmitter path, in which the wireless communication device converts the location-determining signal from the first frequency to the second frequency;

transmitting the location-determining signal at the second frequency to one or more location-determining receivers tuned to the second frequency; and

determining, at the one or more location-determining receivers, the location of the wireless communication device.

2. The method of claim 1, wherein the location-determining system is a global positioning satellite (GPS) system, the location-determining signal is a GPS signal, and the location-determining receiver is a GPS receiver.

3. The method of claim 1, wherein the location-determining receivers are associated with the one or more control stations.

4. The method of claim 1, further comprising the steps of:

filtering the location-determining signal;

down-converting the filtered location-determining signal;

filtering the down-converted signal; and

amplifying the down-converted signal, prior to the step of converting.

5. The method of claim 1, wherein the first frequency is approximately 1575.42 MHz, and the second frequency is a mobile radiotelephone communication frequency.

6. The method of claim 5, wherein the mobile radiotelephone communication frequency is a CDMA channel frequency.

7. The method of claim 1, wherein the transmission of the communication signals is performed at a first power level, and the transmission of the frequency-converted location-determining signal is performed at a second power level greater than the first power level.

8. The method of claim 3, further comprising the step of:

transmitting, prior to the transmitting of the frequency-converted location-determining signal, a precursor signal to the one or more control stations associated with the one or more location-determining receivers; and

suspending, at the one or more control stations, communication links with other wireless communication devices at the second frequency.

9. The method of claim 1, wherein there are at least two location-determining receivers and the step of determining is performed by:

predicting a location of a first location-determining receiver;

comparing the predicted location with a known location of the first location-determining receiver to determine error correction factors; and

determining a location of the wireless communication device at a second location-determining receiver using the determined error correction factors.

10. A wireless communication device, comprising:

wireless communication means for communicating with one or more control stations on one or more communication channels; and

location-determining means for receiving a location-determining signal from a location-determining transmitter, and communicating with one or more location-determining receivers associated with the one or more control stations on the one or more communication channels,

wherein the location determining means includes a switching means for switching a transmitter path in the wireless communication device from a first transmitter path, in which the wireless communication device transmits communication signals to the one or more control stations at a second frequency, to a second transmitter path, in which the wireless communication device converts the location-determining signal from a first frequency to the second frequency and transmits the location-determining signal at the second frequency to said one or more location-determining receivers.

11. The device of claim 10, wherein the location-determining signal is a GPS signal, the location-determining receivers are GPS receivers, and the location-determining transmitter is a GPS satellite.

12. The device of claim 10, wherein the first frequency is approximately 1575.42 MHz, and the one or more communication channels are CDMA communication channels.

13. The device of claim 10, wherein the device transmits a precursor signal prior to communicating with the location-determining receivers, the precursor signal causing each control station associated with the location-determining receivers which receive the precursor signal to suspend communication links with other wireless communication devices at the second frequency.

14. The device of claim 10, wherein the device communicates with the control stations at a first power level and communicates with the location-determining receivers at a second power level greater than the first power level.

15. A communication system, comprising:

one or more control stations associated with one or more wireless communication devices, each wireless communication device having means for exchanging communication signals with the one or more control stations on one or more communication channels; and

location-determining equipment having means for transmitting a location-determining signal to a wireless communication device at a location-determining frequency, receiving a frequency-converted version of the location-determining signal from the wireless communication device, and determining the location of the wireless communication device from the frequency-converted version,

wherein the wireless communication device includes a switching means for switching a transmitter path in the wireless communication device from a first transmitter path, in which the wireless communication device transmits communication signals to the one or more control stations at a first frequency, to a second transmitter path, in which the wireless communication device converts the location-determining signal from the location-determining frequency to the first frequency and transmits the location-determining signal at the first frequency to said location-determining equipment.

16. The system of claim 15, wherein the location-determining equipment includes one or more location-determining transmitters for transmitting the location-determining signal, and one or more location-determining receivers associated with the one or more control stations for receiving the frequency-converted version of the location-determining signal.

17. The system of claim 15, wherein the location-determining frequency is approximately 1575.42 MHz.

18. The system of claim 15, wherein the frequency-converted version has a frequency within one of the communication channels.

19. The system of claim 18, wherein the frequency-converted version is transmitted at a power level greater than the power level of the communication signals.

20. The system of claim 16, wherein each control station associated with a location-determining receiver suspends communication with wireless communication devices communicating on the same channel as the frequency-converted version of the location-determining signal, in response to the location-determining receiver receiving the frequency-converted version of the location-determining signal.