Method and system for processing positioning signals in a geometric mode

• US 6,774,841 B2
• Filed: 01/07/2003
• Issued: 08/10/2004
• Est. Priority Date: 07/18/2001
• Status: Expired due to Term

• Current Assignee: Fast Location.Net, LLC
• Original Assignee: Fast Location.Net, LLC
• Inventors: Jandrell, Louis Henry Martin
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US10/338,094
• Publication Number:
  US 20030137450A1
• Time in Patent Office: 581 Days
• Field of Search: 342/357.05, 342/357.12, 342/357.06, 701/213
• US Class Current: 342/357.64
• CPC Class Codes: G01S 19/05 providing aiding data
• CPC Class Codes: G01S 19/09 providing processing capability normally carried out by the receiver
• CPC Class Codes: G01S 19/17 Emergency applications
• CPC Class Codes: G01S 19/235 Calibration of receiver components
• CPC Class Codes: G01S 19/254 relating to Doppler shift of satellite signals
• CPC Class Codes: G01S 19/256 relating to timing, e.g. time of week, code phase, timing offset
• CPC Class Codes: G01S 19/258 relating to the satellite constellation, e.g. almanac, ephemeris data, lists of satellites in view
• CPC Class Codes: G01S 19/29 carrier including Doppler, related G01S19/246 takes precedence
• CPC Class Codes: G01S 19/34 Power consumption
• CPC Class Codes: G01S 19/35 Constructional details or hardware or software details of the signal processing chain
• CPC Class Codes: G01S 2205/008 using a mobile telephone network
• CPC Class Codes: G01S 5/0018 Transmission from mobile station to base station
• CPC Class Codes: G01S 5/0063 of measured values, i.e. measurement on base station and position calculation on mobile

Abstract

A method for processing positioning signals in a ranging receiver in a geometric mode is provided. The method includes receiving timing information from a first set of satellites in a satellite constellation at the ranging receiver. The satellite constellation includes a plurality of satellites. A time of day is determined based on the received timing information. Approximate location data for the ranging receiver is determined. A frequency bias for the ranging receiver is determined. Ephemeris data is received from a second set of satellites in the satellite constellation. Superframe data for the satellite constellation is received from a third set of satellites in the satellite constellation at the ranging receiver. A pseudorange estimate is determined in the ranging receiver based on the time of day, the approximate location data, the frequency bias, the ephemeris data, and the superframe data.

Claims

1. A method for removing message data modulation from positioning signals received at a ranging receiver from a transmitter, the positioning signals comprising pseudorange samples, the method comprising:

obtaining a transmitter identifier, a Doppler frequency shift, and a Doppler rate for each of a plurality of transmitters;

determining a message bit transition offset for each transmitter;

determining a specified number of message data bits for each transmitter;

compensating each of the pseudorange samples for carrier frequency offset; and

multiplying each of the compensated pseudorange samples by a corresponding stored message data bit value.

2. The method of claim 1, obtaining a transmitter identifier, a Doppler frequency shift, and a Doppler rate for each of a plurality of transmitters comprising obtaining a transmitter identifier, a Doppler frequency shift, and a Doppler rate for each of a plurality of transmitters based on geometric prediction.

3. The method of claim 1, each message bit transition offset comprising a transit time for the positioning signals received from the corresponding transmitter.

4. The method of claim 1, the specified number of message data bits determined by dividing a maximum number of samples by a number of samples per message data bit.

5. The Method of claim 1, the transmitter comprising a satellite transmitter.

6. A system for removing message data modulation from positioning signals received at a ranging receiver from a transmitter, the positioning signals comprising pseudorange samples, the system comprising:

a computer-processable medium; and

logic stored on the computer-processable medium, the logic operable to obtain a transmitter identifier, a Doppler frequency shift, and a Doppler rate for each of a plurality of transmitters, to determine a message bit transition offset for each transmitter, to determine a specified number of message data bits for each transmitter, to compensate each of the pseudorange samples for carrier frequency offset, and to multiply each of the compensated pseudorange samples by a corresponding stored message data bit.

7. The system of claim 6, the logic operable to obtain a transmitter identifier, a Doppler frequency shift, and a Doppler rate for each of a plurality of transmitters based on geometric prediction.

8. The system of claim 6, each message bit transition offset comprising a transit time for the positioning signals received from the corresponding transmitter.

9. The system of claim 6, the logic further operable to determine the specified number of message data bits by dividing a maximum number of samples by a number of samples per message data bit.

10. A system for removing message data modulation from positioning signals received at a ranging receiver from a transmitter, the positioning signals comprising pseudorange samples, the system comprising:

means for obtaining a transmitter identifier, a Doppler frequency shift, and a Doppler rate for each of a plurality of transmitters;

means for determining a message bit transition offset for each transmitter;

means for determining a specified number of message data bits for each transmitter;

means for compensating each of the pseudorange samples for carrier frequency offset; and

means for multiplying each of the compensated pseudorange samples by a corresponding stored message data bit.

11. The system of claim 10, the means for obtaining a transmitter identifier, a Doppler frequency shift, and a Doppler rate for each of a plurality of transmitters comprising means for obtaining a transmitter identifier, a Doppler frequency shift, and a Doppler rate for each of a plurality of transmitters based on geometric prediction.

12. The system of claim 10, each message bit transition offset comprising a transit time for the positioning signals received from the corresponding transmitter.

13. The system of claim 10, the specified number of message data bits determined by dividing a maximum number of samples by a number of samples per message data bit.

14. A method for removing message data modulation from positioning signals received at a ranging receiver from a transmitter, the positioning signals comprising pseudorange samples, the method comprising:

obtaining a transmitter identifier, a Doppler frequency shift, and a Doppler rate based on geometric prediction for each of a plurality of transmitters;

determining a message bit transition offset for each transmitter, each message bit transition offset comprising a transit time for the positioning signals received from the corresponding transmitter;

determining a specified number of message data bits for each transmitter, the specified number of message data bits determined by dividing a maximum number of samples by a number of samples per message data bit;

compensating each of the pseudorange samples for carrier frequency offset; and

multiplying each of the compensated pseudorange samples by a corresponding stored message data bit.