Locator and method for a wireless communication system

• US 5,873,048 A
• Filed: 07/27/1995
• Issued: 02/16/1999
• Est. Priority Date: 07/27/1995
• Status: Expired due to Fees

• Current Assignee: AT&T IPM Corp. (AT&T, Inc.)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Yun, Paul Munsang
• Primary Examiner(s): LE, THANH C
• Application Number:
  US08/508,574
• Time in Patent Office: 1,300 Days
• Field of Search: 455/33.1, 455/33.3, 455/53.1, 455/54.1, 455/56.1, 455/62, 455/63, 455/67.1, 455/272, 455/275, 455/276.1, 455/277.1, 455/278.1, 455/324, 455/422, 455/423 , 455/436, 455/440, 455/441, 455/456, 455/457, 455/507, 455/517, 455/524, 455/561, 455/562, 342/359, 342/372, 379/59, 375/322, 375/326, 375/329, 375/334, 324/760.11, 324/76.19
• US Class Current: 455/446
• CPC Class Codes: G01S 11/10 using Doppler effect
• CPC Class Codes: G01S 3/28 using amplitude comparison of signals derived simultaneously from receiving antennas or antenna systems having differently-oriented directivity characteristics
• CPC Class Codes: G01S 3/325 Automatic tracking systems
• CPC Class Codes: G01S 5/04 Position of source determined by a plurality of spaced direction-finders
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 76/20 Manipulation of established connections

Abstract

A passive locator and method for a wireless communication system. The locator (56) at base station (12) determines the position and trajectory of wireless terminal (22). The passive locator (56) adjusts azimuthal and elevational angles of a directional antenna (58) until a relative maximum power is detected in the signal transmitted from the wireless terminal (22). A processing circuit (60) determines the trajectory of the wireless terminal (22) by generating and analyzing data that represents the Doppler effect on the signal from the wireless terminal (22).

Claims

1. A passive locator for a base station in a wireless communication system, said locator comprising:

a directional antenna that receives a signal from a wireless terminal;

a processing circuit responsive to said directional antenna that measures the power of a signal received from the wireless terminal so as to adjust the orientation of said directional antenna by detecting a relative maximum power in the signal from the wireless terminal so as to determine the location of said wireless terminal; and

said processing circuit further operable to convert the signal from the wireless terminal into data so as to determine a trajectory of the wireless terminal, said processing circuitry includes a down conversion circuit responsive to said directional antenna that demodulates the signal received from the wireless terminal into in-phase and quadrature signals and further includes first and second phase discriminator circuits responsive to said in-phase and quadrature signals, respectively, that each generate two or more sets of corresponding phase tapped outputs of the signals from said down conversion circuit integrated over a symbol period such that each set corresponds to a selected trajectory with respect to said base station.

2. The passive locator of claim 1, wherein said computer determines the trajectory of the wireless terminal by calculating the phase and magnitude of the corresponding phase tapped outputs of the first and second phase discriminators and comparing the phase and magnitudes to select the phase tapped output with the largest phase and magnitude.

3. The locator of claim 1, wherein said directional antenna being directed to the direction of an incoming signal by adjusting azimuthal and elevational angles of said directional antenna.

4. The locator of claim 1, and further comprising an antenna controller responsive to said processing circuit to adjust said directional antenna.

5. The locator of claim 1, wherein said directional antenna comprises a gimbal antenna.

6. The locator of claim 1, wherein said processing circuit comprises:

a spectrum analyzer responsive to said directional antenna that measures the power in a signal received from the wireless terminal; and

a computer responsive to said spectrum analyzer that compares successive power measurements from said spectrum analyzer so as to generate control signals for said antenna controller.

7. The locator of claim 1, wherein said processing circuit comprises a circuit that determines the trajectory of the wireless terminal from the Doppler effect on the frequency of the signal of the wireless terminal.

8. The locator of claim 1, wherein said directional antenna being in addition to at least one antenna which receives signals from said wireless terminal.

9. The locator of claim 1, wherein said orientation of said directional antenna is mechanically adjusted toward the wireless terminal.

10. The locator of claim 1, wherein said computer determines the trajectory of the wireless terminal by calculating the phase and magnitude of the corresponding phase tapped outputs of the first and second phase discriminators and comparing the phase and magnitudes to select the phase tapped output with the largest phase and magnitude.

11. A method for determining the position and trajectory of a wireless terminal in a wireless communication system, said method comprising the steps of:

measuring the power of a signal transmitted from the wireless terminal to a directional antenna;

adjusting the orientation of the directional antenna until the directional antenna is oriented so as to receive a relative maximum power of the signal from the wireless terminal;

demodulating the signal received from the wireless terminal into in-phase and quadrature signals with a down conversion circuit; and

generating two or more sets of corresponding phase tapped outputs of the signals from the down conversion circuit integrated over a symbol period such that each set corresponds to a selected trajectory with respect to said base station using first and second phase discriminator circuits responsive to said in-phase and quadrature signals, respectively.

12. The method of claim 11 further comprises the steps of;

calculating the phase and magnitude of the corresponding phase tapped outputs of the first and second phase discriminators; and

comparing the phase and magnitudes to select a phase tapped output corresponding to the trajectory of the wireless terminal.

13. A wireless infrastructure comprising:

at least one mobile switching center coupled to a public switched telephone network; and

at least one base station responsive to said mobile switching center, said base station including a passive locator circuit, said passive locator circuit comprising;

a directional antenna that receives a signal from a wireless terminal;

a processing circuit responsive to said directional antenna that measures the power of a signal received from the wireless terminal so as to adjust the orientation of said directional antenna by detecting a relative maximum power in the signal from the wireless terminal so as to determine the location of said wireless terminal; and

said processing circuit further operable to convert the signal from the wireless terminal into data so as to determine a trajectory of the wireless terminal, said processing circuitry including a down conversion circuit responsive to said directional antenna that demodulates the signal received from the wireless terminal into in-phase and quadrature signals and first and second phase discriminator circuits responsive to said in-phase and quadrature signals, respectively, that each generate two or more sets of corresponding phase tapped outputs of the signals from said down conversion circuit integrated over a symbol period such that each set corresponds to a selected trajectory with respect to said base station.

14. The wireless infrastructure of claim 13, wherein said computer determines the trajectory of the wireless terminal by calculating the phase and magnitude of the corresponding phase tapped outputs of the first and second phase discriminators and comparing the phase and magnitudes to select the phase tapped output with the largest phase and magnitude.

15. A method for determining the position and trajectory of a wireless terminal in a wireless communication system, said method comprising the steps of:

measuring the power of a signal transmitted from the wireless terminal to a directional antenna;

adjusting the orientation of the directional antenna until the directional antenna is oriented so as to receive a relative maximum power of the signal from the wireless terminal;

converting the signal from the wireless terminal into in-phase and quadrature signals;

generating two or more sets of corresponding phase tapped outputs from said in-phase and quadrature signals integrated over a symbol period such that each set corresponds to a selected trajectory with respect to said base station using first and second phase discriminator circuits responsive to said in-phase and quadrature signals, respectively;

calculating the phase and magnitude of the corresponding phase tapped outputs of the first and second phase discriminators; and

comparing the phase and magnitudes to select a phase tapped output corresponding to the trajectory of the wireless terminal.

16. A base station comprising:

a passive locator, comprising;

a directional antenna that receives a signal from the wireless terminal;

a processing circuit responsive to said directional antenna that measures the power of the signal received from the wireless terminal so as to adjust the orientation of said directional antenna by detecting a relative maximum power in the signal from the wireless terminal so as to determine the position of said wireless terminal; and

said processing circuit further including a data generator that converts the signal from the wireless terminal into two or more sets of data for a component signal of the signal from the wireless terminal such that each set corresponds to a trajectory for the wireless terminal, and a computer responsive to the data generator that manipulates the sets of data to determine the trajectory of the wireless terminal from the Doppler effect.

17. The base station of claim 16, wherein said directional antenna being directed to the direction of an incoming signal by adjusting azimuthal and elevational angles of said directional antenna.

18. The base station of claim 16, and further comprising an antenna controller responsive to said processing circuit to adjust said directional antenna.

19. The base station of claim 16, wherein said directional antenna comprises a gimbal antenna.

20. The base station of claim 16, wherein said processing circuit comprises:

a spectrum analyzer that measures the power in a signal received from the wireless terminal; and

a computer responsive to said spectrum analyzer that compares successive power measurements from said spectrum analyzer so as to generate control signals for said antenna controller.

21. The base station of claim 16, wherein said processing circuit comprises a circuit that determines the trajectory of the wireless terminal from the Doppler effect on the frequency of the signal of the wireless terminal.

22. The base station of claim 16, wherein said data generator comprises:

a down conversion circuit responsive to said directional antenna that demodulates the signal received from the wireless terminal into in-phase and quadrature signals; and

first and second phase discriminator circuits responsive to said in-phase and quadrature signals, respectively, that each generate two or more sets of corresponding phase tapped outputs of the signals from said down conversion circuit integrated over a symbol period such that each set corresponds to a selected trajectory with respect to said base station.

23. The base station of claim 22, wherein said computer determines the trajectory of the wireless terminal by calculating the phase and magnitude of the corresponding phase tapped outputs of the first and second phase discriminators and comparing the phase and magnitudes to select the phase tapped output with the largest phase and magnitude.

24. The base station of claim 16, wherein said orientation of said directional antenna is mechanically adjusted toward the wireless terminal.

25. The base station of claim 16, wherein said directional antenna being in addition to at least one antenna which receives signals from said wireless terminal.

26. A method for determining the trajectory of a wireless terminal in a wireless communication system, said method comprising the steps of:

converting the signal received from the wireless terminal into in-phase and quadrature signals; and

generating two or more sets of corresponding phase tapped outputs of the in-phase and quadrature signals integrated over a period such that each set corresponds to a trajectory using first and second phase discriminator circuits responsive to said in-phase and quadrature signals, respectively.

27. The method of claim 26 further comprising the steps of:

calculating the phase and magnitude of the corresponding phase tapped outputs of the first and second phase discriminator circuits; and

comparing the phase and magnitudes to select a phase tapped output corresponding to the trajectory of the wireless terminal.

28. The method of claim 26 further comprising the steps of:

measuring the power of the signal transmitted from the wireless terminal to a directional antenna; and

adjusting the orientation of the directional antenna until the directional antenna is oriented so as to receive a relative maximum power of the signal from the wireless terminal.