Method and system for data detection in a global positioning system satellite receiver

• US 20050264446A1
• Filed: 07/06/2005
• Published: 12/01/2005
• Est. Priority Date: 04/18/2000
• Status: Active Grant

• Current Assignee: CSR Technology Incorporated (Qualcomm, Inc.)
• Original Assignee: SIRF Technology Incorporated (Qualcomm, Inc.)
• Inventors: Gronemeyer, Steven A., Underbrink, Paul A.
• Granted Patent: US 7,269,511 B2
• Time in Patent Office: Days
• US Class Current: 342/357.620
• CPC Class Codes: G01S 19/24 Acquisition or tracking or demodulation of signals transmitted by the system synchronisation aspects of direct sequence spread spectrum modulation H04B1/7073
• CPC Class Codes: G01S 19/243 Demodulation of navigation message
• CPC Class Codes: G01S 19/30 code related G01S19/246 takes precedence
• CPC Class Codes: G01S 19/37 Hardware or software details of the signal processing chain
• CPC Class Codes: H04B 1/707 using direct sequence modulation

Abstract

A data detection circuit within a global positioning system (GPS) satellite receiver operates to detect and decode data sent in a spread spectrum signal. The data detection circuit receives input from a radio receiver, the information containing data from a plurality of satellites. The data is supplied to a circular memory device, which determines which data corresponds to which satellite. The memory device sends the received signal to a matched filter, which decodes the signal received from each satellite. This signal is analyzed to determine whether a phase inversion due to data modulation on the received signal is present. The phase inversion can occur at boundaries, known as data epochs, in the received signal, and corresponds to data in the received signal. This data contains information relating to the position of each satellite and is collected by the data detection circuit for use by the GPS receiver.

Claims

1-19. -19. (canceled)

20. A GPS receiver, comprising:

a first GPS antenna coupled to a digital memory, the digital memory storing first digitized signals obtained through the first GPS antenna;

a second GPS antenna coupled to the digital memory, the digital memory storing second digitized signals obtained through the second GPS antenna;

a digital processor coupled to the digital memory, the digital processor processing the first digitized signals after being stored in the digital memory to provide first position information and processing the second digitized signals after being stored in the digital memory to provide second position information;

a receiver, including data detection circuitry configured to decode data encoded upon a spread spectrum modulated signal using a matched filter residing within the receiver, the data being demarcated into successive data epochs; and

wherein the matched filter decodes periodic phase shift data encoded upon the signal by phase shifts of the data epochs.

21-27. -27. (canceled)

28. A method of tracking a remote object comprising the steps of:

fitting a remote object with a positioning sensor configured to receive and store positioning information when the remote object is in a fix position;

positioning the remote object in a fix position such that the positioning sensor is capable of detecting an activation signal;

receiving and storing a predetermined amount of data in the positioning sensor, the data comprising position information;

processing the data to determine the location of the fix position;

decoding data encoded upon a signal using a matched filter, the data being demarcated into successive data epochs; and

decoding periodic phase shift data encoded upon the signal by phase shifts of the data epochs using the matched filter.

29-36. -36. (canceled)