Data message bit synchronization and local time correction methods and architectures
First Claim
1. A method for data message bit synchronization of a spread spectrum signal having a repeating sequence of pseudorandom code bits modulated with data message bits having a data bit time that is an integer number of a repeat time of the pseudorandom code bits, comprising:
- receiving a first spread spectrum signal;
determining a code phase delay;
performing a plurality of coherent correlations at the determined code phase delay between the first spread spectrum signal and a first replica signal for a time interval corresponding to the data bit time;
the plurality of coherent correlations corresponding in number to the integer number of the repeat time of the pseudorandom code bits;
offsetting each of the coherent correlations relative to a previous correlation by the repeat time of the pseudorandom code bits;
determining a magnitude of each of the plurality of coherent correlations;
generating a plurality of non-coherent sums of magnitudes for each of the plurality of coherent correlations over at least two data bit times, the plurality of non-coherent sums of magnitudes corresponding in number to the integer number of the repeat time of the pseudorandom code bits.
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Abstract
Methods and architectures for data message bit synchronization of a spread spectrum signal having a repeating sequence of pseudorandom code bits modulated with data message bits having a data bit time that is an integer number of a repeat time of the pseudorandom code bits. In one embodiment, an adjusted bit sync offset time is determined for each of a plurality of signals for which bit sync offset time is not known based on a corresponding clock error corrected propagation time for each signal, based on a known bit synch offset time and based on a clock error corrected propagation time of the signal for which bit synch offset time is known.
104 Citations
18 Claims
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1. A method for data message bit synchronization of a spread spectrum signal having a repeating sequence of pseudorandom code bits modulated with data message bits having a data bit time that is an integer number of a repeat time of the pseudorandom code bits, comprising:
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receiving a first spread spectrum signal;
determining a code phase delay;
performing a plurality of coherent correlations at the determined code phase delay between the first spread spectrum signal and a first replica signal for a time interval corresponding to the data bit time;
the plurality of coherent correlations corresponding in number to the integer number of the repeat time of the pseudorandom code bits;
offsetting each of the coherent correlations relative to a previous correlation by the repeat time of the pseudorandom code bits;
determining a magnitude of each of the plurality of coherent correlations;
generating a plurality of non-coherent sums of magnitudes for each of the plurality of coherent correlations over at least two data bit times, the plurality of non-coherent sums of magnitudes corresponding in number to the integer number of the repeat time of the pseudorandom code bits. - View Dependent Claims (2, 3, 4)
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5. A method for data message bit synchronization of a spread spectrum signal having a repeating sequence of pseudorandom code bits modulated with data message bits having a data bit time that is an integer number of a repeat time of the pseudorandom code bits, comprising:
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receiving a first spread spectrum signal;
determining a range of code phase uncertainty;
performing a plurality of coherent correlations over the range of code phase uncertainty between the first spread spectrum signal and a first replica signal for a time interval corresponding to the data bit time,;
the plurality of coherent correlations corresponding in number to the integer number of the repeat time of the pseudorandom code bits;
offsetting each of the plurality of coherent correlations relative to a previous coherent correlation by the repeat time of the pseudorandom code bits;
determining a magnitude of each of the plurality of coherent correlations;
generating a plurality of non-coherent sums of magnitudes for each of the plurality of coherent correlations over at least two data bit times, the plurality of non-coherent sums of magnitudes corresponding in number to the integer number of the repeat time of the pseudorandom code bits. - View Dependent Claims (6, 7)
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8. A method for data message bit synchronization of a spread spectrum signal having a repeating sequence of pseudorandom code bits modulated with data message bits having a data bit time that is an integer number of a repeat time of the pseudorandom code bits, comprising:
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receiving a spread spectrum signal;
forming a plurality of sequential signal segments by sequentially segmenting the spread spectrum signal;
performing a plurality of sequential partial coherent correlations on each of the plurality of sequential signal segments with a corresponding sequential segment of a replica signal, the plurality of sequential partial coherent correlations corresponding in number to the integer number of the repeat time of the pseudorandom code bits;
summing sequential results of the plurality of sequential partial coherent correlations performed on the plurality of sequential signal segments for a time corresponding to the data bit time;
offsetting each of the plurality of summed sequential results relative to another by a distinct multiple of the repeat time of the pseudorandom code bits;
generating a plurality of non-coherent sums of magnitudes for each of the plurality of coherent correlations over at least two data bit times, the plurality of non-coherent sums of magnitudes corresponding in number to the integer number of the repeat time of the pseudorandom code bits. - View Dependent Claims (9, 10, 11)
storing results of the sequential partial coherent correlations in a corresponding plurality of memory locations corresponding in number to the integer number of the repeat time; storing the summed sequential partial correlation results in the plurality of memory locations.
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12. A method for data bit synchronization of a receiver with a plurality of signals based on a known bit synch offset time for one signal, known approximate receiver and signal source locations, and known signal source clock correction parameters for each of the plurality of signals, comprising:
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determining a propagation time between the receiver and sources of each of the plurality of signals;
determining a clock error corrected propagation time from the approximate position of the receiver to the source of each of the plurality of signals based on the corresponding propagation times and the corresponding signal source clock correction parameters;
determining an adjusted bit sync offset time for each of the plurality of signals for which bit sync offset time is not known based on the corresponding clock error corrected propagation time for each signal, based on the known bit synch offset time and based on the clock error corrected propagation time of the signal for which bit synch offset time is known. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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Specification