Method and apparatus for signal processing in a satellite positioning system
AssigneeSnapTrack, Inc.
InventorNorman F. Krasner
Life of this patent
Estimating the term…
Abstract
A method and apparatus for processing satellite positioning system (SPS) signals which are weak in level. In one embodiment, a SPS receiver receives at least two signal samples representing, at least in part, common information, wherein the two signal samples are associated with one or more satellite messages. By combining the two signal samples, navigational information (e.g., time, position, velocity, etc.) may be determined based on the combination of the two signal samples. According to another embodiment, the two signal samples are differentially demodulated and summed together to form the combination.
Claims82
A method for satellite positioning system (SPS) signal processing, said method comprising:
- receiving at an SPS receiver one or more SPS signals;
- removing pseudorandom noise from said one or more SPS signals to provide a first portion of a narrowband signal and a second portion of a narrowband signal;
- and
- summing said first and second portions, at least one of said first and second portions being weighted by a weighting factor that is a function of a signal-to-noise ratio (SNR) of at least one of said one or more SPS signals to improve the sensitivity of the SPS receiver;
- wherein said first portion and said second portion contain common information in said one or more SPS signals.
A method for processing a signal associated with a satellite positioning system, said method comprising:
- receiving at an SPS receiver a first SPS signal containing a satellite message associated with a satellite vehicle;
- receiving at said SPS receiver a second SPS signal containing said satellite message associated with said satellite vehicle;
- removing pseudorandom noise from said first and second SPS signals to provide a first set of signal samples of a narrowband signal and a second set of signal samples of a narrowband signal;
- and
- summing said first and second sets of signal samples to improve the sensitivity of the SPS receiver, said summing including weighting at least one of said first and second sets of signal samples with a weight depending on a signal-to-noise ratio (SNR) of at least one of said first and second sets of signal samples;
- wherein said first set of signal samples and said second set of signal samples contain common information.
A method for satellite positioning system signal processing, said method comprising:
- receiving at an SPS receiver a first SPS signal containing a first satellite message, said first satellite message associated with a first satellite vehicle;
- receiving at said SPS receiver a second SPS signal containing a second satellite message, said second satellite message associated with a second satellite vehicle;
- removing pseudorandom noise from said first and second SPS signals to provide a first set of signal samples of a narrowband signal and a second set of signal samples of a narrowband signal;
- combining said first and second sets of signal samples to improve the sensitivity of the SPS receiver;
- wherein said first set of signal samples and said second set of signal samples contain common information;
- receiving at said SPS receiver a third SPS signal containing said first satellite message;
- receiving at said SPS receiver a fourth SPS signal containing said second satellite message;
- removing pseudorandom noise of said third and forth SPS signals to provide a third set of signal samples of a narrowband signal and a fourth set of signal samples of a narrowband signal, wherein said third and fourth sets of signal samples at least partially represent common information;
- combining representations of said third and fourth sets of signal samples;
- and
- comparing a first result generated from combining said first and second signal samples with a second result generated from combining said representations of said third and fourth signal samples to determine navigational information.
An apparatus to provide satellite positioning system (SPS) signal processing, said apparatus comprising:
- a despreader that removes pseudorandom noise from one or more SPS signals to provide a first portion of a narrowband signal and a second portion of a narrowband signal;
- a processor, coupled to said despreader, to combine said first portion with said second portion to improve the sensitivity of the SPS receiver;
- said processor performing a summing operation to said first portion and said second portion, said summing operation including a weighting factor that is a function of a signal-to-noise ratio (SNR);
- wherein said first portion and said second portion contain common information.
An apparatus to provide satellite positioning system (SPS) signal processing, said apparatus comprising:
- means for removing pseudorandom noise from one or more SPS signals to provide a first portion of a narrowband signal and a second portion of a narrowband signal;
- and
- means for combining said first portion with said second portion to improve the sensitivity of the SPS receiver;
- wherein said means for combining adds in a summing operation said first portion with said second portion, and wherein said summing operation comprises including a weighting factor, said weighting factor being a function of a signal-to-noise ratio (SNR);
- wherein said first portion and said second portion contain common information.
An apparatus to provide satellite positioning system (SPS) signal processing, said apparatus comprising:
- a correlator, said correlator receiving one or more SPS signals;
- and
- a navigation computer coupled to the correlator, said navigation computer removing pseudorandom noise from said one or more SPS signals to provide a first portion of a narrowband signal and a second portion of a narrowband signal, said navigation computer summing said first portion with said second portion, wherein said summing operation includes a weighting factor that is a function of a signal-to-noise ratio (SNR) to improve the sensitivity of the apparatus;
- wherein said first portion and said second portion contain common information.
The apparatus of claim 71, wherein said navigation computer sums said first and second portions after said navigation computer differentially demodulates said first and second portions.
The apparatus of claim 71, wherein said navigation computer adds in a summing operation said first portion with said second portion following a differentially demodulating operation.
An apparatus to provide satellite positioning system (SPS) signal processing, said apparatus comprising:
- means for receiving at an SPS receiver one or more SPS signals;
- means for removing pseudorandom noise from said one or more SPS signals to provide a first portion of a narrowband signal and a second portion of a narrowband signal;
- means for summing said first and second portions, at least one of said first and second portions being weighted with a weighting factor that is a function of a signal-to-noise ratio (SNR) of at least one of said one or more SPS signals to improve the sensitivity of the SPS receiver;
- wherein said first portion and said second portion contain common information in said one or more SPS signals.
Dependencies are inferred from the claim text.