Method and apparatus for receiving GPS/GLONASS signals

• US 6,967,992 B1
• Filed: 11/19/1998
• Issued: 11/22/2005
• Est. Priority Date: 11/19/1997
• Status: Expired due to Fees

• Current Assignee: Interuniversitair Micro-Electronica Centrum VZW (IMEC International)
• Original Assignee: Interuniversitair Micro-Electronica Centrum VZW (IMEC International)
• Inventors: Aardoom, Eric, Rabaeijs, Alain, Gyselinckx, Bert, Engels, Marc
• Primary Examiner(s): Corrielus, Jean B.
• Application Number:
  US09/196,658
• Time in Patent Office: 2,560 Days
• Field of Search: 375/130, 375/140, 375/142, 375/147, 375/150, 342/352, 342/357.06, 342/357.12
• US Class Current: 375/150
• CPC Class Codes: G01S 19/22 Multipath-related issues
• CPC Class Codes: G01S 19/30 code related G01S19/246 takes precedence
• CPC Class Codes: G01S 19/32 Multimode operation in a single same satellite system, e.g. GPS L1/L2
• CPC Class Codes: G01S 19/33 Multimode operation in different systems which transmit time stamped messages, e.g. GPS/GLONASS
• 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

An electronic system for receiving spread spectrum signals, in particular GPS and/or GLONASS signals is described. In particular, the functional specification for the design of an advanced GPS and/or GLONASS receiver (AGGR) is disclosed. The AGGR is preferably fabricated including at least one sub-system implemented as an application specific integrated circuit (ASIC). The present disclosure describes the AGGR functionality and its modes of operation to a detail allowing a future user of the device to understand its features and limitations and to assess its suitability for an envisaged application. A method and an apparatus are described for processing received spread spectrum signals modulated with a unique pseudo-random code including a capability of hierarchically chaining a plurality of channel modules in series, specific forms of delay line units and correlator units which can process CA-code, P-code and Y-code signals.

Claims

1. An apparatus for processing L1 and L2 spread spectrum signals received from at least one satellite of a global positioning system, wherein each of the spread spectrum signals includes a unique frequency carrier with a known pseudo-random known code modulated thereon, each L1 and L2 signal being converted into a plurality of digital signals, the apparatus comprising:

a generator for generating a single replica of the known code;

a delay line connected to the generator, the delay line having a plurality of taps wherefrom the known code replica is available at different relative phases thereof;

a first demodulator connected to the generator for demodulating the converted L1 and L2 signals with the single replica of the known code without any substantial delay, the first demodulator output being associated with the L1 signal;

a second demodulator selectably connectable to any one of the taps of the delay line for demodulating the converted L1 and L2 signals with a delayed replica of the known code, the second demodulator output being associated with the L2 signal; and

switches for selectably switching the converted L1 and L2 signals for demodulation by the second demodulator, and selectably switching the converted L1 and L2 signals for demodulation by the first demodulator.

2. A method of processing L1 and L2 spread spectrum signals received from at least one satellite of a global positioning system, wherein each of the signals includes a unique frequency carrier with a known pseudo-random code modulated thereon, each L1 and L2 signal being converted into a plurality of digital signals, the method comprising:

locally generating a single replica of the known code;

applying the single replica of the known code to a delay line having a plurality of taps wherefrom the code replica is available at different relative phases thereof;

first demodulating the converted L1 and L2 signals with the single replica of the known code without any substantial delay, the first demodulated signal being associated with the L1 signal;

second demodulating the converted L1 and L2 signals with the generated replica of the known code from one of the taps of the delay line, the second demodulated signal being associated with the L2 signal; and

selectably switching the converted L1 and L2 signals for the first demodulation and selectably switching the converted L1 and L2 signals for the second demodulation.