Signal acquisition using data bit information

• US 6,512,479 B1
• Filed: 06/22/2001
• Issued: 01/28/2003
• Est. Priority Date: 06/22/2001
• Status: Expired due to Term

• Current Assignee: CSR Technology Holdings Inc. (Qualcomm, Inc.)
• Original Assignee: Enuvis Inc. (Qualcomm, Inc.)
• Inventors: Roy, Benjamin Van, Sahai, Anant, Chou, Andrew, Mann, Wallace
• Primary Examiner(s): PHAN, DAO LINDA
• Application Number:
  US09/888,228
• Time in Patent Office: 585 Days
• Field of Search: 342/357.05, 342/357.06, 342/357.12, 342/357.15, 701/213, 701/215
• US Class Current: 342/357.63
• CPC Class Codes: G01S 19/06 employing an initial estimate of the location of the receiver as aiding data or in generating aiding data
• CPC Class Codes: G01S 19/09 providing processing capability normally carried out by the receiver
• 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 19/30 code related G01S19/246 takes precedence

Abstract

Techniques are provided for aiding in acquiring a signal using the data bit information that is associated with each signal source. One aspect of the invention is to use the data bit information that is associated with each signal source when calculating the In Phase and Quadrature correlation integrals by using the sampled data associated with the received signal. By using the data bit information that is associated with each signal source, coherent correlation may be performed by breaking the signal into data blocks and performing calculations on a block-by-block basis. Coherent correlation is the calculation of In Phase and Quadrature correlation integrals for sampled data that is associated with the received signal.

Claims

1. A method for aiding in an acquisition of an acquired signal from a received signal, the method comprising the computer-implemented steps of:

receiving sampled data associated with the received signal;

receiving data bit information that indicates which portions of an emitted signal have changes in sign corresponding to flips in a C/A PRN code of the signal source associated with the received signal;

mixing the sampled data to produce a mixed sampled data;

dividing the mixed sampled data into a plurality of data blocks; and

for each block of the plurality of blocks using the data bit information for computing I and Q correlation integrals between the sampled data and the emitted signal.

2. The method of claim 1, wherein computing the correlation integrals further comprises making a code-phase adjustment that is based on at least one Doppler information that is a member of a set of Doppler information that includes a receiver-Doppler information, a source-Doppler information and a relative motion-Doppler information, wherein:

the receiver-Doppler information is associated with a receiver that produces and sends the sampled data;

the source-Doppler information is associated with the signal source; and

the relative motion Doppler is associated with a relative motion of the signal source to the receiver.

3. The method of claim 1, wherein the correlation integrals are associated with I and Q correlation integrals corresponding to an In Phase component and a Quadrature component respectively of the sampled data.

4. The method of claim 2, wherein making the code-phase adjustment is performed by multiplying an appropriate complex function with Fast Fourier Transforms of I and Q correlation integrals, wherein the I and Q correlation integrals correspond to the I and Q correlation integrals.

5. The method of claim 2, wherein making the code-phase adjustment is performed by multiplying an appropriate complex function with Fast Fourier Transforms of a reference signal that is associated with the signal source.

6. The method of claim 2, wherein making the code-phase adjustment is performed by multiplying an appropriate complex function with Fast Fourier Transforms of the mixed sampled data.

7. The method of claim 1, wherein the sampled data is digitized data produced by digitizing the received signal.

8. The method of claim 1, wherein mixing the sampled data involves mixing with a receiver-Doppler information, a source-Doppler information and a relative motion Doppler information, wherein:

the receiver-Doppler information is associated with a receiver that produces and sends the sampled data;

the source-Doppler information is associated with the signal source; and

the relative motion Doppler information is associated with a relative motion of the signal source to the receiver.

9. The method of claim 1, wherein for each data block of the plurality of data blocks and using the data bit information for computing the correlation integrals involves computing I and Q correlation integrals over a range of hypothesized delay values for the sampled data.

10. The method of claim 1, wherein for each data block of the plurality of data blocks and using the data bit information for computing the correlation integrals involves computing Fast Fourier Transforms of I and Q correlation integrals over a range of hypothesized delay values for each data block.

11. The method of claim 9, further comprising the step of:

for each hypothesized delay value in the range of hypothesized delay values, summing the I and Q correlation integrals respectively, over all the data blocks of the plurality of data blocks using the data bit information.

12. The method of claim 10, further comprising the steps of:

summing Fast Fourier Transforms of the I and Q correlation integrals for the data blocks using the data bit information; and

performing an inverse Fast Fourier Transform to obtain the I and Q correlation integrals for each hypothesized delay value.

13. The method of claim 1, further comprising the steps of:

summing the mixed sampled data over subsets of data blocks using the data bit information to produced summed data blocks; and

computing the I and Q correlation integrals based on the summed data blocks; and

summing the I and Q correlation integrals over all the data blocks.

14. The method of claim 9, further comprising the steps of:

for each hypothesized delay value in the range of hypothesized delay values, calculating a magnitude of the I and Q correlation integrals that were previously summed over all the data blocks, to produce a set of magnitude calculations, wherein the set of magnitude calculations correspond to the range of hypothesized delay values; and

determining that the acquired signal is acquired if a highest peak is greater than a predetermined value, wherein the highest peak is identified from the set of magnitude calculations.

15. The method of claim 9, wherein a range of hypothesized delay values is based on:

an approximate time that the receiver received the received signal;

a relative approximate position information between the signal source and the receiver; and

any known uncertainties in the approximate time and the relative approximate position information.

16. A method for aiding in an acquisition of an acquired signal from a received signal, the method comprising the computer-implemented steps of:

receiving sampled data associated with the received signal;

receiving data bit information that indicates which portions of an emitted signal changes in sign corresponding to flips in a C/A PRN code corresponding to the signal source associated with the received signal;

mixing the sampled data with a receiver-Doppler information, a source-Doppler information and a motion-Doppler information to produce a mixed sampled data, wherein;

the receiver-Doppler information is associated with a receiver that sends the sampled data;

the source-Doppler information is associated with the signal source; and

the relative motion Doppler information is associated with a relative motion of the signal source to the receiver;

dividing the mixed sampled data into a plurality of data blocks;

for each data block of the plurality of data blocks and using the data bit information, computing, over a range of hypothesized delay values, I and Q correlation integrals corresponding to an In Phase component and a Quadrature component respectively of the mixed sampled data;

for each hypothesized delay value in the range of hypothesized delay values, summing the I and Q correlation integrals respectively, over all the data blocks of the plurality of data blocks using the data bit information;

for each hypothesized delay value in the range of hypothesized delay values, calculating a magnitude of the I and Q correlation integrals that were previously summed over all the data blocks, to produce a set of magnitude calculations, wherein the set of magnitude calculations correspond to the range of hypothesized delay values.

17. A method for acquiring an acquired signal from a received signal, the method comprising the computer-implemented steps of:

receiving sampled data associated with the received signal;

receiving data bit information that indicates which portions of an emitted signal changes in sign corresponding to flips in a C/A PRN code corresponding to the signal source associated with the received signal;

mixing the sampled data with a receiver-Doppler information, a source-Doppler information, and a motion-Doppler information to produce a mixed sampled data, wherein;

the receiver-Doppler information is associated with a receiver that sends the sampled data;

the source-Doppler information is associated with the signal source;

the relative motion Doppler information is associated with a relative motion of the signal source to the receiver;

dividing the mixed sampled data into a plurality of data blocks;

for each data block of the plurality of data blocks and using the data bit information, computing Fast Fourier Transforms of I and Q correlation integrals, over a range of hypothesized delay values;

summing the Fast Fourier Transforms of I and Q correlation integrals for the data blocks using the data bit information over the range of hypothesized delay values; and

performing an inverse Fast Fourier Transform to obtain the I and Q correlation integrals for each hypothesized delay value;

for each hypothesized delay value in the range of hypothesized delay values, calculating a magnitude of the I and Q correlation integrals that were previously summed over all the data blocks, to produce a set of magnitude calculations, wherein the set of magnitude calculations correspond to the range of hypothesized delay values; and

determining that the acquired signal is acquired if a highest peak is greater than a predetermined value, wherein the highest peak is identified from the set of magnitude calculations.

18. A method for aiding in an acquisition of an acquired signal from a received signal, the method comprising the computer-implemented steps of:

digitizing the received signal by a receiver to produce sampled data;

receiving from the receiver the sampled data;

receiving data bit information that indicates which portions of an emitted signal changes in sign corresponding to flips in a C/A PRN code corresponding to the signal source associated with the received signal;

mixing the sampled data with a receiver-Doppler information, a source-Doppler information and a motion-Doppler information to produce a mixed sampled data, wherein;

the receiver-Doppler information is associated with a receiver that sends the sampled data;

the source-Doppler information is associated with the signal source; and

the relative motion Doppler information is associated with a relative motion of the signal source to the receiver;

dividing the mixed sampled data into a plurality of data blocks;

for each data block of the plurality of data blocks and using the data bit information, computing, over a range of hypothesized delay values, I and Q correlation integrals corresponding to an In Phase component and a Quadrature component respectively of the mixed sampled data;

for each hypothesized delay value in the range of hypothesized delay values, summing the I and Q correlation integrals respectively, over all the data blocks of the plurality of data blocks using the data bit information;

for each hypothesized delay value in the range of hypothesized delay values, calculating a magnitude of the I and Q correlation integrals that were previously summed over all the data blocks, to produce a set of magnitude calculations, wherein the set of magnitude calculations correspond to the range of hypothesized delay values.

19. A method for acquiring an acquired signal from a received signal, the method comprising the computer-implemented steps of:

digitizing the received signal by a receiver to produce sampled data;

receiving from the receiver the sampled data;

receiving data bit information that indicates which portions of an emitted signal changes in sign corresponding to flips in a C/A PRN code corresponding to the signal source associated with the received signal;

mixing the sampled data with a receiver-Doppler information, a source-Doppler information, and a motion-Doppler information to produce a mixed sampled data, wherein;

the receiver-Doppler information is associated with a receiver that sends the sampled data;

the source-Doppler information is associated with the signal source;

the relative motion Doppler information is associated with a relative motion of the signal source to the receiver;

dividing the mixed sampled data into a plurality of data blocks;

for each data block of the plurality of data blocks and using the data bit information, computing, over a range of hypothesized delay values, I and Q correlation integrals corresponding to an In Phase component and a Quadrature component respectively of the sampled data;

for each hypothesized delay value in the range of hypothesized delay values, summing the I and Q correlation integrals respectively, over all the data blocks of the plurality of data blocks using the data bit information;

for each hypothesized delay value in the range of hypothesized delay values, calculating a magnitude of the I and Q correlation integrals that were previously summed over all the data blocks, to produce a set of magnitude calculations, wherein the set of magnitude calculations correspond to the range of hypothesized delay values; and

determining that the acquired signal is acquired if a highest peak is greater than a predetermined value, wherein the highest peak is identified from the set of magnitude calculations.