Split C/A code receiver

Claim 2

A GPS receiver for receiving split-C/A coded signals, the receiver including: A. a C/A code generator for generating a locally-generated C/A-code; B. a square-wave code generator for generating a locally-generated square-wave code; C. means for producing a locally-generated split-C/A code, said means digitally mixing the locally-generated C/A code and the locally-generated square-wave code; D. correlators for producing correlation measurements for use in: (i) synchronizing the locally-generated square-wave code with the square-wave code included in the received signal; (ii) synchronizing the locally-generated C/A code with the C/A code included in the received signal; and (iii) synchronizing the locally-generated split-C/A code with the split C/A code included in the received signal; and E. means for adjusting the phase of the square-wave code produced by the square-wave code generator in response to the correlation measurements associated with the locally-generated square-wave code; and F. means for adjusting the phase of the C/A code produced by the C/A code generator relative to the phase of the locally-generated square wave code in response to the correlation measurements associated with the locally-generated C/A code.

Claim 3

The receiver of claim 1 wherein: the square-wave code generator is a code NCO; and the means for adjusting the phase of the locally-generated square-wave code also adjusts the phase of the split-C/A code in accordance with correlation measurements associated with the locally-generated split-C/A code.

Claim 4

The receiver of claim 2 wherein the means for shifting the phase of the C/A code is a divide-by-ten divider that divides down the square-wave code signal produced by the code NCO to produce the clock signal for the C/A code generator.

Claim 5

The receiver of claim 3 wherein the means for shifting the phase of the C/A code includes a means for stealing whole or partial cycles from or adding whole or partial cycles to a clock that controls the divide-by-ten divider.

Claim 6

The receiver of claim 1 further including carrier synchronizing means for aligning a locally-generated carrier with a carrier in the received signal.

Claim 7

The receiver of claim 5 wherein the carrier synchronizing means provides carrier information to the means for aligning the square-wave code to compensate for relative movement of the receiver and a satellite that transmits the split-C/A code.

Claim 10

The method of claim 7 further including the step of producing the locally-generated split-C/A code by digitally mixing the locally-generated square-wave code and the locally-generated C/A code.

Claim 11

The method of claim 7 further including the step of aligning a locally-generated carrier with a carrier in the received signal.

Claim 12

The method of claim 9 further including the step of using carrier alignment information to adjust the phase of the locally-generated square-wave code.

Claim 15

The method of claim 11 further including the step of producing the locally-generated split-C/A code by digitally mixing the locally-generated square-wave code and the locally-generated C/A code.

Claim 16

The method of claim 11 further including the step of aligning a locally-generated carrier with a carrier in the received signal.

Claim 17

The method of claim 13 further including the step of using carrier alignment information to adjust the phase of the locally-generated square-wave code.

Claim 18

A GPS receiver for receiving split-C/A coded signals, the receiver including: A. a C/A code generator for generating a locally-generated C/A-code; B. a square-wave code generator for generating a locally-generated square-wave code; C. a multiplier for producing a locally-generated split-C/A code, the multiplier digitally mixing the locally-generated C/A code and the locally-generated square-wave code; D. correlators for producing correlation measurements for use in: (i) synchronizing the locally-generated square-wave code with the square-wave code included in the received signal; (ii) synchronizing the locally-generated C/A code with the C/A code included in the received signal; and (iii) synchronizing the locally-generated split-C/A code with the split C/A code included in the received signal; and E. a controller for i. adjusting the phase of the square-wave code produced by the square-wave code generator in response to the correlation measurements associated with the locally-generated square-wave code; and ii. adjusting the phase of the C/A code produced by the C/A code generator relative to the phase of the locally-generated square wave code in response to the correlation, measurements associated with the locally-generated C/A code.

Claim 19

A GPS receiver for receiving split-C/A coded signals, the receiver including: A. a C/A code generator for generating a locally-generated C/A-code; B. a square-wave code generator for generating a locally-generated square-wave code; C. a multiplier for producing a locally-generated split-C/A code, the multiplier digitally mixing the locally-generated C/A code and the locally-generated square-wave code; D. correlators for producing correlation measurements for use in: (i) synchronizing the locally-generated square-wave code with the square-wave code included in the received signal; (ii) synchronizing the locally-generated C/A code with the C/A code included in the received signal; and (iii) synchronizing the locally-generated split-C/A code with the split C/A code included in the received signal; and E. a controller for i. adjusting the phase of the square-wave code produced by the square-wave code generator in response to the correlation measurements associated with the locally-generated square-wave code; and ii. adjusting the phase of the C/A code produced by the C/A code generator relative to the phase of the locally-generated square wave code in response to the correlation, measurements associated with the locally-generated C/A code.

Claim 20

The receiver of claim 15 wherein: a. the square-wave code generator is a code NCO; and b. the controller further adjusts the phase of the locally-generated split-C/A code in accordance with correlation measurements associated with the split-C/A code.

Claim 21

The receiver of claim 16 further including c. a divide-by-ten divider that divides down the square-wave code signal produced by the code NCO to produce the clock signal for the C/A code generator, and d. the controller controls the divide-by-ten counter to adjust the phase of the locally-generated C/A code relative to the locally-generated square wave code.

Claim 22

The receiver of claim 17 wherein the controller controls the divide-by-ten counter by stealing whole or partial cycles from or adding whole or partial cycles to a clock that is included in the divide-by-ten divider.

Claim 23

The receiver of claim 15 further including carrier synchronizing means for aligning a locally-generated carrier with a carrier in the received signal.

Claim 24

The receiver of claim 19 wherein the carrier synchronizing means provides carrier information to the controller, and the controller uses the carrier information to control the code generators and compensate for relative movement of the receiver and a satellite that transmits the split-C/A code.