Patent US4821294A successfully refreshed from Google Patents.
US4821294A
Expired / Lapsed
US
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Digital signal processor and processing method for GPS receivers
Assignee: California Institute of Technology
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Filing: 1987-07-08
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Granted: 1989-04-11
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Expires: 2007-07-08
Abstract
Abstract A digital signal processor and processing method therefor for use in receivers of the NAVSTAR/GLOBAL POSITIONING SYSTEM (GPS) employs a digital carrier down-converter, digital code correlator and digital tracking processor. The digital carrier down-converter and code correlator consists of an all-digital, minimum bit implementation that utilizes digital chip and phase advancers, providing exceptional control and accuracy in feedback phase and in feedback delay. Roundoff and commensurability errors can be reduced to extremely small values (e.g., less than 100 nanochips and 100 nanocycles roundoff errors and 0.1 millichip and 1 millicycle commensurability errors). The digital tracking processor bases the fast feedback for phase and for group delay in the C/A, P 1 , and P 2 channels on the L 1 C/A carrier phase thereby maintaining lock at lower signal-to-noise ratios, reducing errors in feedback delays, reducing the frequency of cycle slips and in some cases obviating the need for quadrature processing in the P channels. Simple and reliable methods are employed for data bit synchronization, data bit removal and cycle counting. Improved precision in averaged output delay values is provided by carrier-aided data-compression techniques. The signal processor employs purely digital operations in the sense that exactly the same carrier phase and group delay measurements are obtained, to the last decimal place, every time the same sampled data (i.e., exactly the same bits) are processed.
Inventors
- 👤 Jess B. Thomas, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:49
CPC Classifications
G; G01; G01S; G01S19/00; G01S19/01; G01S19/13; G01S19/24; G01S19/30
Claims Analysis
Total Claims: 48
Claim 1
Independent Claim
165 words
A digital signal processor for use in a Global Positioning System (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequence, and generating model carrier phases that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of the code-modulated signal; the processor comprising: means for generating counter-rotation sinusoids from model phases; means for counter-rotating the carrier phase of the digitized signal with said counter-rotation sinusoids; means for multiplying the counter-rotated signal with the model code values and accumulating the multiplication produces over respective selected time intervals; means for processing the accumulated products to obtain model phase and model delay; and means for modifying model carrier phase to obtain fast feedback models for code group delays.
Claim 2
Dependent Claim
165 words
A digital signal processor for use in a Global Positioning System (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequence, and generating model carrier phases that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of the code-modulated signal; the processor comprising: means for generating counter-rotation sinusoids from model phases; means for counter-rotating the carrier phase of the digitized signal with said counter-rotation sinusoids; means for multiplying the counter-rotated signal with the model code values and accumulating the multiplication produces over respective selected time intervals; means for processing the accumulated products to obtain model phase and model delay; and means for modifying model carrier phase to obtain fast feedback models for code group delays.
Claim 3
Dependent Claim
32 words
The digital signal processor recited in claim 1 further comprising: means for applying slow feedback corrections to the fast feedback models, for code group delay, by using accumulated products at selected intervals.
Claim 4
Dependent Claim
165 words
A digital signal processor for use in a Global Positioning System (GPS) receiver, the receiver of the type receiving at least two code-modulated signals, providing digitized signals from said code-modulated signals, generating model delays, generating model code sequences that are time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequences, and generating model carrier phases that are closely matched to received carrier phases, for accurately measuring the code group delay and carrier phase of each code-modulated signal; the processor comprising: means for generating counter-rotation sinusoids from model phases; means for counter-rotating the carrier phases of the digitized signals with said counter-rotation sinusoids; means for multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective selected time intervals; means for processing the accumulated products to obtain model phases and model delays; and means for modifying model carrier phase to obtain fast feedback models for code group delays.
Claim 5
Dependent Claim
165 words
A digital signal processor for use in a Global Positioning System (GPS) receiver, the receiver of the type receiving at least two code-modulated signals, providing digitized signals from said code-modulated signals, generating model delays, generating model code sequences that are time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequences, and generating model carrier phases that are closely matched to received carrier phases, for accurately measuring the code group delay and carrier phase of each code-modulated signal; the processor comprising: means for generating counter-rotation sinusoids from model phases; means for counter-rotating the carrier phases of the digitized signals with said counter-rotation sinusoids; means for multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective selected time intervals; means for processing the accumulated products to obtain model phases and model delays; and means for modifying model carrier phase to obtain fast feedback models for code group delays.
Claim 6
Dependent Claim
32 words
The digital signal processor recited in claim 3 further comprising: means for applying slow feedback corrections to the fast feedback models, for code group delays, by using accumulated products at selected intervals.
Claim 7
Dependent Claim
178 words
A digital signal processor for use in a Global Positioning System (GPS) receiver, the receiver of the type receiving at least two code-modulated signals, providing digitized signals from said code-modulated signals, generating model delays, generating model code sequences that are time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequences, and generating model carrier phases that are closely matched to received carrier phases, for accurately measuring the code group delay and carrier phase of each code-modulated signal; the processor comprising: means for generating counter-rotation sinusoids from model phases; means for counter-rotating the carrier phases of the digitized signals with said counter-rotation sinusoids; means for multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective selected time intervals; means for processing the accumulated products to obtain model phases and model delays; and means for modifying the model carrier phase of one of said code-modulated signals to obtain a fast feedback model for the carrier phase of another such code-modulated signal.
Claim 8
Dependent Claim
178 words
A digital signal processor for use in a Global Positioning System (GPS) receiver, the receiver of the type receiving at least two code-modulated signals, providing digitized signals from said code-modulated signals, generating model delays, generating model code sequences that are time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequences, and generating model carrier phases that are closely matched to received carrier phases, for accurately measuring the code group delay and carrier phase of each code-modulated signal; the processor comprising: means for generating counter-rotation sinusoids from model phases; means for counter-rotating the carrier phases of the digitized signals with said counter-rotation sinusoids; means for multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective selected time intervals; means for processing the accumulated products to obtain model phases and model delays; and means for modifying the model carrier phase of one of said code-modulated signals to obtain a fast feedback model for the carrier phase of another such code-modulated signal.
Claim 9
Dependent Claim
187 words
A digital signal processor for use in a Global Positioning System (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequence, and generating model carrier phases that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of the code-modulated signal; the processor comprising: means for generating counter-rotation sinusoids from model phases; means for counter-rotating the carrier phase of the digitized signal with said counter-rotation sinusoids; means for multiplying the counter-rotated signal with the model code values and accumulating the multiplication products over respective selected time intervals; means for processing the accumulated products to obtain model phase and model delay; and means for averaging measured code group delays over a selected short averaging interval by using concurrently measured values for carrier phase to remove the averaged effects of time variations of the code group delays over said interval.
Claim 10
Dependent Claim
187 words
A digital signal processor for use in a Global Positioning System (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequence, and generating model carrier phases that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of the code-modulated signal; the processor comprising: means for generating counter-rotation sinusoids from model phases; means for counter-rotating the carrier phase of the digitized signal with said counter-rotation sinusoids; means for multiplying the counter-rotated signal with the model code values and accumulating the multiplication products over respective selected time intervals; means for processing the accumulated products to obtain model phase and model delay; and means for averaging measured code group delays over a selected short averaging interval by using concurrently measured values for carrier phase to remove the averaged effects of time variations of the code group delays over said interval.
Claim 11
Dependent Claim
187 words
A digital signal processor for use in a Global Positioning System (GPS) receiver, the receiver of the type receiving at least two code-modulated signals, providing digitized signals from said code-modulated signals, generating model delays, generating model code sequences that are time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequences, and generating model carrier phases that are closely matched to received carrier phases, for accurately measuring the code group delay and carrier phase of each code-modulated signal; the processor comprising: means for generating counter-rotation sinusoids from model phases; means for counter-rotating the carrier phases of the digitized signals with said counter-rotation sinusoids; means for multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective selected time intervals; means for processing the accumulated products to obtain model phases and model delays; and means for averaging measured code group delays over a selected short averaging interval and using concurrently measured values for carrier phase to remove the averaged effects of time variations of the code group delays over said interval.
Claim 12
Dependent Claim
187 words
A digital signal processor for use in a Global Positioning System (GPS) receiver, the receiver of the type receiving at least two code-modulated signals, providing digitized signals from said code-modulated signals, generating model delays, generating model code sequences that are time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequences, and generating model carrier phases that are closely matched to received carrier phases, for accurately measuring the code group delay and carrier phase of each code-modulated signal; the processor comprising: means for generating counter-rotation sinusoids from model phases; means for counter-rotating the carrier phases of the digitized signals with said counter-rotation sinusoids; means for multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective selected time intervals; means for processing the accumulated products to obtain model phases and model delays; and means for averaging measured code group delays over a selected short averaging interval and using concurrently measured values for carrier phase to remove the averaged effects of time variations of the code group delays over said interval.
Claim 13
Dependent Claim
181 words
A digital signal processor for use in a Global Positioning System (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequence, and generating model carrier phase that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of the code-modulated signal; the processor comprising: means for generating counter-rotation sinusoids from model phases; means for counter-rotating the carrier phase of the digitized signal with said counter-rotation sinusoids; means for multiplying the counter-rotated signal with the model code values and accumulating the multiplication products over respective selected time intervals; means for processing the accumulated products to obtain model phase and model delay; and means for extracting measured carrier phase for a code-modulated signal by extracting residual phase from the accumulated products and then adding said residual phase to the model phase for the interval.
Claim 14
Dependent Claim
181 words
A digital signal processor for use in a Global Positioning System (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequence, and generating model carrier phase that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of the code-modulated signal; the processor comprising: means for generating counter-rotation sinusoids from model phases; means for counter-rotating the carrier phase of the digitized signal with said counter-rotation sinusoids; means for multiplying the counter-rotated signal with the model code values and accumulating the multiplication products over respective selected time intervals; means for processing the accumulated products to obtain model phase and model delay; and means for extracting measured carrier phase for a code-modulated signal by extracting residual phase from the accumulated products and then adding said residual phase to the model phase for the interval.
Claim 15
Dependent Claim
182 words
A digital signal processor for use in a Global Positioning system (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequence, and generating model carrier phases that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of the code-modulated signal; the processor comprising: means for generating counter-rotation sinusoids from model phases; means for counter-rotating the carrier phase of the digitized signal with said counter-rotation sinusoids; means for multiplying the counter-rotated signal with the model code values and accumulating the multiplication products over respective selected time intervals; means for processing the accumulated products to obtain model phase and model delay; and means for extracting measured code group delay for a code-modulated signal by extracting residual delay from the accumulated products and then adding said residual delay to the model delay for the interval.
Claim 16
Dependent Claim
182 words
A digital signal processor for use in a Global Positioning system (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequence, and generating model carrier phases that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of the code-modulated signal; the processor comprising: means for generating counter-rotation sinusoids from model phases; means for counter-rotating the carrier phase of the digitized signal with said counter-rotation sinusoids; means for multiplying the counter-rotated signal with the model code values and accumulating the multiplication products over respective selected time intervals; means for processing the accumulated products to obtain model phase and model delay; and means for extracting measured code group delay for a code-modulated signal by extracting residual delay from the accumulated products and then adding said residual delay to the model delay for the interval.
Claim 17
Dependent Claim
207 words
A digital signal processor for use in a Global Positioning System (GPS) receiver, the receiver of the type receiving at least two code-modulated signals, providing digitized signals from said code-modulated signals, generating model delays, generating model code sequences that are time offset by the model delays so that the resulting mode code values are closely aligned in time with the received code sequence, and generating model carrier phases that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of each code-modulated signal; the processor comprising: means for generating counter-rotation sinusoids from model phases; means for counter-rotating the carrier phase of the digitized signals with said counter-rotation sinusoids; means for multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective selected time intervals; means for processing the accumulated products to obtain model phases and model delays; said receiver also receiving a data signal superimposed upon said code-modulated signals, said processor further comprising means for testing the logic sign of the accumulated products for extracting a data bit sign therefrom for a data-bit interval; and means for removing the data-bit signal from one code-modulated signal based upon the data-bit sign extracted from another code-modulated signal.
Claim 18
Dependent Claim
207 words
A digital signal processor for use in a Global Positioning System (GPS) receiver, the receiver of the type receiving at least two code-modulated signals, providing digitized signals from said code-modulated signals, generating model delays, generating model code sequences that are time offset by the model delays so that the resulting mode code values are closely aligned in time with the received code sequence, and generating model carrier phases that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of each code-modulated signal; the processor comprising: means for generating counter-rotation sinusoids from model phases; means for counter-rotating the carrier phase of the digitized signals with said counter-rotation sinusoids; means for multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective selected time intervals; means for processing the accumulated products to obtain model phases and model delays; said receiver also receiving a data signal superimposed upon said code-modulated signals, said processor further comprising means for testing the logic sign of the accumulated products for extracting a data bit sign therefrom for a data-bit interval; and means for removing the data-bit signal from one code-modulated signal based upon the data-bit sign extracted from another code-modulated signal.
Claim 19
Dependent Claim
197 words
A digital signal processor for use in a Global Positioning System (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequence, and generating model carrier phases that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of each code-modulated signal; the processor comprising: means for generating counter-rotation sinusoids from model phases; means for counter-rotating the carrier phase of the digitized signal with said counter-rotation sinusoids; means for multiplying the counter-rotated signal with the model code values and accumulating the multiplication products over respective selected time intervals; means for processing the accumulated products to obtain model phase and model delay; said receiver also receiving a data signal having defined data-bit intervals and being superimposed upon said code-modulated signal; and said digital processor further comprising means for synchronizing the product accumulation intervals with the data-bit intervals by offsetting accumulation interval start time with a previously measured code group delay.
Claim 20
Dependent Claim
197 words
A digital signal processor for use in a Global Positioning System (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequence, and generating model carrier phases that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of each code-modulated signal; the processor comprising: means for generating counter-rotation sinusoids from model phases; means for counter-rotating the carrier phase of the digitized signal with said counter-rotation sinusoids; means for multiplying the counter-rotated signal with the model code values and accumulating the multiplication products over respective selected time intervals; means for processing the accumulated products to obtain model phase and model delay; said receiver also receiving a data signal having defined data-bit intervals and being superimposed upon said code-modulated signal; and said digital processor further comprising means for synchronizing the product accumulation intervals with the data-bit intervals by offsetting accumulation interval start time with a previously measured code group delay.
Claim 21
Dependent Claim
172 words
A digital signal processor for use in a Global Positioning System (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequence, and generating model carrier phase that are closely matched to received carrier phase for accurately measuring the code group delay and carrier phase of each code-modulated signal; the processor comprising: means for generating counter-rotation sinusoids from model phases; means for counter-rotating the carrier phase of the digitized signal with said counter-rotation sinusoids; means for multiplying the counter-rotated signal with the model code values and accumulating the multiplication products over respective selected time intervals; means for processing the accumulated products to obtain model phase and model delay; and means for estimating model carrier phase over a future time interval by two-point linear extrapolation of measured phase from prior time intervals.
Claim 22
Dependent Claim
172 words
A digital signal processor for use in a Global Positioning System (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequence, and generating model carrier phase that are closely matched to received carrier phase for accurately measuring the code group delay and carrier phase of each code-modulated signal; the processor comprising: means for generating counter-rotation sinusoids from model phases; means for counter-rotating the carrier phase of the digitized signal with said counter-rotation sinusoids; means for multiplying the counter-rotated signal with the model code values and accumulating the multiplication products over respective selected time intervals; means for processing the accumulated products to obtain model phase and model delay; and means for estimating model carrier phase over a future time interval by two-point linear extrapolation of measured phase from prior time intervals.
Claim 23
Dependent Claim
196 words
A digital signal processor for use in a Global Positioning System (GPS) receiver, the receiver of the type receiving at least two code-modulated signals, providing digitized signals from said code-modulated signals, generating model delays, generating model code sequences that are time offset by t he model delays so that the resulting mode code values are closely aligned in time with the received code sequences, and generating model carrier phases that are closely matched to received carrier phases, for accurately measuring the code group delay and carrier phase of each code-modulated signal; the processor comprising: means for generating counter-rotation sinusoids from model phases; means for counter-rotating the carrier phases of the digitized signals with said counter-rotation sinusoids; means for multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective selected time intervals; means for processing the accumulated products to obtain model phases and model delays; and means for averaging measured carrier phase values of one code-modulated signal over a selected short averaging interval by using concurrently measured values of carrier phase of another code-modulated signal to remove the averaged effects of time variation in said one carrier phase over said interval.
Claim 24
Dependent Claim
196 words
A digital signal processor for use in a Global Positioning System (GPS) receiver, the receiver of the type receiving at least two code-modulated signals, providing digitized signals from said code-modulated signals, generating model delays, generating model code sequences that are time offset by t he model delays so that the resulting mode code values are closely aligned in time with the received code sequences, and generating model carrier phases that are closely matched to received carrier phases, for accurately measuring the code group delay and carrier phase of each code-modulated signal; the processor comprising: means for generating counter-rotation sinusoids from model phases; means for counter-rotating the carrier phases of the digitized signals with said counter-rotation sinusoids; means for multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective selected time intervals; means for processing the accumulated products to obtain model phases and model delays; and means for averaging measured carrier phase values of one code-modulated signal over a selected short averaging interval by using concurrently measured values of carrier phase of another code-modulated signal to remove the averaged effects of time variation in said one carrier phase over said interval.
Claim 25
Independent Claim
158 words
A method of digitally processing signals in a Global Positioning System (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned n time with the received code sequence, and generating model carrier phases that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of the code-modulated signal; the method comprising the steps of: generating counter-rotation sinusoids from model phases; counter-rotating the carrier phase of the digitized signals with said counter-rotation sinusoids; multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective selected time intervals; processing the accumulated products to obtain model phase and model delay; and modifying model carrier phase to obtain fast feedback models for code groups delays.
Claim 26
Independent Claim
158 words
A method of digitally processing signals in a Global Positioning System (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned n time with the received code sequence, and generating model carrier phases that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of the code-modulated signal; the method comprising the steps of: generating counter-rotation sinusoids from model phases; counter-rotating the carrier phase of the digitized signals with said counter-rotation sinusoids; multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective selected time intervals; processing the accumulated products to obtain model phase and model delay; and modifying model carrier phase to obtain fast feedback models for code groups delays.
Claim 27
Dependent Claim
35 words
The method of digitally processing signals recited in claim 14 further comprising the step of applying slow feedback corrections to the fast feedback models, for code group delay, by using accumulated products at selected intervals.
Claim 28
Independent Claim
159 words
A method of digitally processing signals in a Global Positioning System (GPS) receiver, the receiver of the type receiving at least two code-modulated signals, providing digitized signals from said code-modulated signals, generating model delays, generating model code sequences that are time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequences, and generating model carrier phases that are closely matched to received carrier phases, for accurately measuring the code group delay and carrier phase of each code-modulated signal; the method comprising the steps of: generating counter-rotation sinusoids from model phases; counter-rotating the carrier phases of the digitized signals with said counter rotation sinusoids; multiplying the counter rotated signals with the model code values and accumulating the multiplication products over respective time intervals; processing the accumulated products to obtain model phases and model delays; and modifying model carrier phase to obtain fast feedback models for code group delays.
Claim 29
Independent Claim
159 words
A method of digitally processing signals in a Global Positioning System (GPS) receiver, the receiver of the type receiving at least two code-modulated signals, providing digitized signals from said code-modulated signals, generating model delays, generating model code sequences that are time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequences, and generating model carrier phases that are closely matched to received carrier phases, for accurately measuring the code group delay and carrier phase of each code-modulated signal; the method comprising the steps of: generating counter-rotation sinusoids from model phases; counter-rotating the carrier phases of the digitized signals with said counter rotation sinusoids; multiplying the counter rotated signals with the model code values and accumulating the multiplication products over respective time intervals; processing the accumulated products to obtain model phases and model delays; and modifying model carrier phase to obtain fast feedback models for code group delays.
Claim 30
Dependent Claim
35 words
The method of digitally processing signals recited in claim 16 further comprising the step of applying slow feedback corrections to the fast feedback models, for code group delay, by using accumulated products at selected intervals.
Claim 31
Independent Claim
170 words
A method of digitally processing signals in a Global Positioning System (GPS) receiver, the receiver of the type receiving at least two code-modulated signals, providing digitized signals from said code-modulated signals, generating model delays, generating model code sequences that are time offset by the model delays so that the resulting mode code values are closely aligned in time with the received code sequences, and generating model carrier phases that are closely matched to received carrier phases, for accurately measuring the code group delay and carrier phase of each code-modulated signal; the method comprising the steps of: generating counter-rotation sinusoids from model phases; counter-rotating the carrier phases of the digitized signals with said counter-rotation sinusoids; multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective time intervals; processing the accumulated products to obtain model phases and model delays; and modifying the model carrier phase of one of said code-modulated signals to obtain a fast feedback model for the carrier phase of another such code-modulated signal.
Claim 32
Independent Claim
170 words
A method of digitally processing signals in a Global Positioning System (GPS) receiver, the receiver of the type receiving at least two code-modulated signals, providing digitized signals from said code-modulated signals, generating model delays, generating model code sequences that are time offset by the model delays so that the resulting mode code values are closely aligned in time with the received code sequences, and generating model carrier phases that are closely matched to received carrier phases, for accurately measuring the code group delay and carrier phase of each code-modulated signal; the method comprising the steps of: generating counter-rotation sinusoids from model phases; counter-rotating the carrier phases of the digitized signals with said counter-rotation sinusoids; multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective time intervals; processing the accumulated products to obtain model phases and model delays; and modifying the model carrier phase of one of said code-modulated signals to obtain a fast feedback model for the carrier phase of another such code-modulated signal.
Claim 33
Independent Claim
180 words
A method of digitally processing signals in a Global Positioning system (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequence, and generating model carrier phases that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of the code-modulated signal; the method comprising the steps of: generating counter-rotation sinusoids from model phases; counter-rotating the carrier phase of the digitized signals with said counter-rotation sinusoids; multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective selected time intervals; processing the accumulated products to obtain model phase and model delay; and averaging measured code group delays over a selected short averaging interval by using concurrently measured values for carrier phase to remove the averaged effects of time variations of the code group delays over said interval.
Claim 34
Independent Claim
180 words
A method of digitally processing signals in a Global Positioning system (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequence, and generating model carrier phases that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of the code-modulated signal; the method comprising the steps of: generating counter-rotation sinusoids from model phases; counter-rotating the carrier phase of the digitized signals with said counter-rotation sinusoids; multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective selected time intervals; processing the accumulated products to obtain model phase and model delay; and averaging measured code group delays over a selected short averaging interval by using concurrently measured values for carrier phase to remove the averaged effects of time variations of the code group delays over said interval.
Claim 35
Independent Claim
181 words
A method of digitally processing signals in a Global Positioning System (GPS) receiver, the receiver of the type receiving at least two code-modulated signals, providing digitized signals from said code-modulated signals, generated model delays, generating model code sequences that are time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequences, and generating model carrier phases that are closely matched to received carrier phases, for accurately measuring the code group delay and carrier phase of each code-modulated signal; the method comprising the steps of: generating counter-rotation sinusoids from model phases; counter-rotating the carrier phases of the digitized signals with said counter rotation sinusoids; multiplying the counter rotated signals with the model code values and accumulating the multiplication products over respective time intervals; processing the accumulated products to obtain model phases and model delays; and averaging measured code group delays over a selected short averaging interval and using concurrently measured values for carrier phase to remove the averaged effects of time variations of the code group delays over said interval.
Claim 36
Independent Claim
181 words
A method of digitally processing signals in a Global Positioning System (GPS) receiver, the receiver of the type receiving at least two code-modulated signals, providing digitized signals from said code-modulated signals, generated model delays, generating model code sequences that are time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequences, and generating model carrier phases that are closely matched to received carrier phases, for accurately measuring the code group delay and carrier phase of each code-modulated signal; the method comprising the steps of: generating counter-rotation sinusoids from model phases; counter-rotating the carrier phases of the digitized signals with said counter rotation sinusoids; multiplying the counter rotated signals with the model code values and accumulating the multiplication products over respective time intervals; processing the accumulated products to obtain model phases and model delays; and averaging measured code group delays over a selected short averaging interval and using concurrently measured values for carrier phase to remove the averaged effects of time variations of the code group delays over said interval.
Claim 37
Independent Claim
174 words
A method of digitally processing signals in a Global Positioning System (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequence, and generating model carrier phases that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of the code-modulated signal; the method comprising the steps of: generating counter-rotation sinusoids from model phases; counter-rotating the carrier phase of the digitized signals with said counter-rotation sinusoids; multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective selected time intervals; processing the accumulated products to obtain model phase and model delay; and extracting measured carrier phase for a code-modulated signal by extracting residual phase from the accumulated products and then adding said residual phase to the model phase for the interval.
Claim 38
Independent Claim
174 words
A method of digitally processing signals in a Global Positioning System (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequence, and generating model carrier phases that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of the code-modulated signal; the method comprising the steps of: generating counter-rotation sinusoids from model phases; counter-rotating the carrier phase of the digitized signals with said counter-rotation sinusoids; multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective selected time intervals; processing the accumulated products to obtain model phase and model delay; and extracting measured carrier phase for a code-modulated signal by extracting residual phase from the accumulated products and then adding said residual phase to the model phase for the interval.
Claim 39
Independent Claim
175 words
A method of digitally processing signals in a Global Positioning System (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequence, and generating model carrier phases that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of the code-modulated signal; the method comprising the steps of: generating counter-rotation sinusoids from model phases; counter-rotating the carrier phase of the digitized signals with said counter-rotation sinusoids; multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective selected time intervals; processing the accumulated products to obtain model phase and model delay; and extracting measured code group delay for a code-modulated signal by extracting residual delay from the accumulated products and then adding said residual delay to the model delay for the interval.
Claim 40
Independent Claim
175 words
A method of digitally processing signals in a Global Positioning System (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequence, and generating model carrier phases that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of the code-modulated signal; the method comprising the steps of: generating counter-rotation sinusoids from model phases; counter-rotating the carrier phase of the digitized signals with said counter-rotation sinusoids; multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective selected time intervals; processing the accumulated products to obtain model phase and model delay; and extracting measured code group delay for a code-modulated signal by extracting residual delay from the accumulated products and then adding said residual delay to the model delay for the interval.
Claim 41
Independent Claim
195 words
A method of digitally processing signals in a Global Positioning System (GPS) receiver, the receiver of the type receiving at least two code-modulated signals, providing digitized signals from said code-modulated signals, generating model delays, generating model code sequences that are time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequences, and generating model carrier phases that are closely matched to received carrier phases, for accurately measuring the code group delay and carrier phase of each code-modulated signal; the method comprising the steps of: generating counter-rotation sinusoids from model phases; counter-rotating the carrier phases of the digitized signals with said counter rotation sinusoids; multiplying the counter rotated signals with the model code values and accumulating the multiplication products over respective time intervals; processing the accumulated products to obtain model phases and model delays; receiving a data signal superimposed upon said code-modulated signals, testing the logic sign of the accumulated products for extracting a data bit sign therefrom for a data bit interval; and removing the data bit sign from one code-modulated signal based upon the data bit sign extracted from another code-modulated signal.
Claim 42
Independent Claim
195 words
A method of digitally processing signals in a Global Positioning System (GPS) receiver, the receiver of the type receiving at least two code-modulated signals, providing digitized signals from said code-modulated signals, generating model delays, generating model code sequences that are time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequences, and generating model carrier phases that are closely matched to received carrier phases, for accurately measuring the code group delay and carrier phase of each code-modulated signal; the method comprising the steps of: generating counter-rotation sinusoids from model phases; counter-rotating the carrier phases of the digitized signals with said counter rotation sinusoids; multiplying the counter rotated signals with the model code values and accumulating the multiplication products over respective time intervals; processing the accumulated products to obtain model phases and model delays; receiving a data signal superimposed upon said code-modulated signals, testing the logic sign of the accumulated products for extracting a data bit sign therefrom for a data bit interval; and removing the data bit sign from one code-modulated signal based upon the data bit sign extracted from another code-modulated signal.
Claim 43
Independent Claim
182 words
A method of digitally processing signals in a Global Positioning System (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequence, and generating model carrier phases that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of the code-modulated signal; the method comprising the steps of: generating counter-rotation sinusoids from model phases; counter-rotating the carrier phase of the digitized signals with said counter-rotation sinusoids; multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective selected time intervals; processing the accumulated products to obtain model phase and model delay; receiving a data signal having defined data-bit intervals and being superimposed upon said code-modulated signal; and synchronizing the product accumulation intervals with the data-bit intervals by offsetting accumulation interval start time with a previously measured code group delay.
Claim 44
Independent Claim
182 words
A method of digitally processing signals in a Global Positioning System (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequence, and generating model carrier phases that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of the code-modulated signal; the method comprising the steps of: generating counter-rotation sinusoids from model phases; counter-rotating the carrier phase of the digitized signals with said counter-rotation sinusoids; multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective selected time intervals; processing the accumulated products to obtain model phase and model delay; receiving a data signal having defined data-bit intervals and being superimposed upon said code-modulated signal; and synchronizing the product accumulation intervals with the data-bit intervals by offsetting accumulation interval start time with a previously measured code group delay.
Claim 45
Independent Claim
165 words
A method of digitally processing signals in a Global Positioning System (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequence, and generating model carrier phases that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of the code-modulated signal; the method comprising the steps of: generating counter-rotation sinusoids from model phases; counter-rotating the carrier phase of the digitized signals with said counter-rotation sinusoids; multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective selected time intervals; processing the accumulated products to obtain model phase and model delay; and estimating model carrier phase over a future time interval by two-point linear extrapolation of measured phase from prior time intervals.
Claim 46
Independent Claim
165 words
A method of digitally processing signals in a Global Positioning System (GPS) receiver, the receiver of the type receiving a code-modulated signal, providing a digitized signal from said code-modulated signal, generating model delays, generating a model code sequence that is time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequence, and generating model carrier phases that are closely matched to received carrier phase, for accurately measuring the code group delay and carrier phase of the code-modulated signal; the method comprising the steps of: generating counter-rotation sinusoids from model phases; counter-rotating the carrier phase of the digitized signals with said counter-rotation sinusoids; multiplying the counter-rotated signals with the model code values and accumulating the multiplication products over respective selected time intervals; processing the accumulated products to obtain model phase and model delay; and estimating model carrier phase over a future time interval by two-point linear extrapolation of measured phase from prior time intervals.
Claim 47
Independent Claim
189 words
A method of digitally processing signals in a Global Positioning System (GPS) receiver, the receiver of the type receiving at least two code-modulated signals, providing digitized signals from said code-modulated signals, generating model delays, generating model code sequences that are time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequences, and generating model carrier phases that are closely matched to received carrier phases, for accurately measuring the code group delay and carrier phase of each code-modulated signal; the method comprising the steps of: generating counter-rotation sinusoids from model phases; counter-rotating the carrier phases of the digitized signals with said counter rotation sinusoids; multiplying the counter rotated signals with the model code values and accumulating the multiplication products over respective time intervals; processing the accumulated products to obtain model phases and model delays; and averaging measured carrier phase values of one codemodulated signal over a selected short averaging interval by using concurrently measured values of carrier phase of another code-modulated signal to remove the averaged effects of time variation in said one carrier phase over said interval.
Claim 48
Independent Claim
189 words
A method of digitally processing signals in a Global Positioning System (GPS) receiver, the receiver of the type receiving at least two code-modulated signals, providing digitized signals from said code-modulated signals, generating model delays, generating model code sequences that are time offset by the model delays so that the resulting model code values are closely aligned in time with the received code sequences, and generating model carrier phases that are closely matched to received carrier phases, for accurately measuring the code group delay and carrier phase of each code-modulated signal; the method comprising the steps of: generating counter-rotation sinusoids from model phases; counter-rotating the carrier phases of the digitized signals with said counter rotation sinusoids; multiplying the counter rotated signals with the model code values and accumulating the multiplication products over respective time intervals; processing the accumulated products to obtain model phases and model delays; and averaging measured carrier phase values of one codemodulated signal over a selected short averaging interval by using concurrently measured values of carrier phase of another code-modulated signal to remove the averaged effects of time variation in said one carrier phase over said interval.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1992-04-10 | 1992-10-10 | 1993-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-04-10 | 1996-10-10 | 1997-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-04-10 | 2000-10-10 | 2001-04-11 | $7700.00 | Window Closed / Lapsed |