GNSS signal processing with clock difference modeling
First Claim
1. A method of processing signal data derived from signals received from satellites of two or more GNSS, each GNSS having a respective clock error, comprising:
- eliminating satellite-specific clock errors from the signal data; and
applying to the signal data after elimination of the satellite-specific clock errors a filter defined by a state vector to estimate a set of carrier ambiguities, wherein the state vector comprises a first clock-error state representing clock error of a first GNSS, and a second clock-error state representing a difference between clock error of the first GNSS and clock error of a second GNSS.
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Abstract
Three new methods are presented to improve floating solutions and ambiguity resolution for multiple global satellite navigation systems (GNSS), one of which may be an FDMA-based GNSS such as GLONASS: (1) modeling of the hardware-related differential clock error between two (or more) different GNSS, (2) modeling the frequency-dependent biases present in frequency-division multiple access (FDMA) GNSS, and (3) an ambiguity resolution method called Scoreboard Partial Fixing (SPF). The methods presented are independent of the number of carrier frequencies tracked for each satellite navigation system. Their application results in quicker and more reliable ambiguity resolution. The benefits of combining observations of multiple GNSS are exploited in a very efficient way, in contrast to known algorithms which often result in degraded performance with multiple GNSS. The frequency-dependent bias method has been found effective with GNSS observations from a combination of substantially dissimilar hardware, e.g., for processing signals from GNSS receivers of different manufacturers.
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Citations
21 Claims
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1. A method of processing signal data derived from signals received from satellites of two or more GNSS, each GNSS having a respective clock error, comprising:
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eliminating satellite-specific clock errors from the signal data; and applying to the signal data after elimination of the satellite-specific clock errors a filter defined by a state vector to estimate a set of carrier ambiguities, wherein the state vector comprises a first clock-error state representing clock error of a first GNSS, and a second clock-error state representing a difference between clock error of the first GNSS and clock error of a second GNSS. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 21)
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11. Apparatus comprising a processor for processing signal data derived from signals received from satellites of two or more GNSS, each GNSS having a respective clock error, comprising:
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instructions for eliminating satellite-specific clock errors from the signal data; and instructions for applying to the signal data after elimination of the satellite-specific clock errors a filter defined by a state vector to estimate a set of carrier ambiguities, wherein the state vector comprises a first clock-error state representing clock error of a first GNSS, and a second clock-error state representing a difference between clock error of the first GNSS and clock error of a second GNSS. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification