MULTI-FREQUENCY GNSS RECEIVER BASEBAND DSP

• US 20110057834A1
• Filed: 09/07/2010
• Published: 03/10/2011
• Est. Priority Date: 09/04/2009
• Status: Active Grant

• Current Assignee: Hemisphere GNSS(USA) Incorporated
• Original Assignee: Hemisphere GNSS(USA) Incorporated
• Inventors: Miller, Steven R.
• Granted Patent: US 8,334,804 B2
• Time in Patent Office: Days
• US Class Current: 342/357.25
• CPC Class Codes: G01S 19/37 Hardware or software details of the signal processing chain
• CPC Class Codes: H04B 1/7075 with code phase acquisition
• CPC Class Codes: H04B 1/709 Correlator structure
• CPC Class Codes: H04B 2201/70715 with application-specific features

Abstract

A dual-frequency DSP correlator receives I and Q signal components from a down convertor in a GNSS receiver system. The signal components are cross-wiped (de-spread) for noise cancellation and can be combined for use in a processor.

Claims

1. A multi-frequency, cross-wiping global navigation satellite system (GNSS) receiver system, which comprises:

first and second GNSS RF antennas with respective first and second frequencies;

an analog downconverter connected to said first and second antennas and adapted for down converting analog signals therefrom;

said analog downconverter having sin and cosine functions for modifying said signals from said antennas and providing digital truth terms having in-phase (I) and in-quadrature (Q) components respectively;

a digital downconverter adapted for receiving said analog down converter output and providing I and Q digital signal outputs for said down converted first and second frequencies respectively;

a correlator including;

first and second inputs each including I and Q signal component inputs adapted for receiving the I and Q components of said first and second signals respectively;

an I adder connected to said first and second I component inputs and providing a combined I component output;

a Q adder connected to said first and second Q component inputs and providing a combined Q component output;

a first mixer connected to said I adder output and said second Q component input and adapted for mixing said signal components and providing a first frequency correlator output; and

a second mixer connected to said Q adder output and said first I component input and adapted for mixing said signal components and providing a second frequency correlator output; and

a GNSS solution processor connected to and receiving said first and second frequency cross-wiped single outputs from said correlator and providing GNSS location solutions there from.

2. An analog correlator for cross-wiping first and second digital signals with respective first and second frequencies and in-phase (I) and in-quadrature (Q) signal components, which correlator includes:

first and second inputs each including I and Q signal component inputs adapted for receiving the I and Q components of said first and second signals respectively;

an I adder connected to said first and second I component inputs and providing a combined I component output;

a Q adder connected to said first and second Q component inputs and providing a combined Q component output;

a first mixer connected to said I adder output and said second Q component input and adapted for mixing said signal components and providing a first frequency correlator output; and

a second mixer connected to said Q adder output and said first I component input and adapted for mixing said signal components and providing a second frequency correlator output.

3. A digital correlator for cross-wiping first and second digital signals with respective first and second frequencies, which correlator includes:

first and second inputs adapted for receiving said first and second digital signals respectively;

1st and 2^nd in-phase (I) mixers connected to said 1^st and 2^nd inputs respectively;

1st and 2^nd in-quadrature (Q) mixers connected to said 1^st and 2^nd inputs respectively;

an I adder connected to said first and second I mixers and providing a combined I component output;

a Q adder connected to said first and second Q mixers and providing a combined Q component output;

a first IQ mixer connected to said I adder output and said second Q mixer output and adapted for mixing said signal components and providing a first frequency correlator output; and

a second IQ mixer connected to said Q adder output and said first I mixer output and adapted for mixing said signal components and providing a second frequency correlator output.

4. The correlator according to claim 3 wherein said correlator signals comprise an intermediate frequency.