Ultra short baseline GNSS receiver
First Claim
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1. A GNSS receiver comprising:
- an antenna structure consisting of two or more antennas with each antenna spaced apart from neighboring antennas by less than one wavelength of a carrier signal in GNSS satellite signals;
a phase map that contains carrier phase difference error values associated with angles of incidence of the GNSS satellite signals at the antenna structure and line biases associated with operation of the GNSS receiver and calculated for respective pairs of antennas based on phase difference values;
one or more processors configured to process the GNSS satellite signals received by the antennas and calculate estimated orientation of the antenna structure directly from differences in carrier phase angle measurements of incoming GNSS carrier signals at the antennas, determine the angles of incidence of the respective GNSS satellite signals based on positions of respective satellites and the estimated orientation of the antenna structure, enter the phase map using the angles of incidence and retrieve associated carrier phase difference error values, and utilize the associated carrier phase difference error values to correct the estimated orientation to produce an updated orientation; and
the one or more processors further configured to re-enter the phase map to calculate a new updated orientation, utilizing updated angles of incidence, until a change in the new updated orientation is less than an error gradient associated with the phase map.
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Abstract
A GNSS receiver utilizes an antenna structure that two or more antennas that are spaced apart from their neighboring antennas by less than 1 wavelength of a GNSS satellite carrier signal of interest. The receiver calculates the orientation of the antennas directly from differences in the carrier phase angles measured at the two antennas, without resolving integer carrier cycle ambiguity.
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Citations
17 Claims
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1. A GNSS receiver comprising:
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an antenna structure consisting of two or more antennas with each antenna spaced apart from neighboring antennas by less than one wavelength of a carrier signal in GNSS satellite signals; a phase map that contains carrier phase difference error values associated with angles of incidence of the GNSS satellite signals at the antenna structure and line biases associated with operation of the GNSS receiver and calculated for respective pairs of antennas based on phase difference values; one or more processors configured to process the GNSS satellite signals received by the antennas and calculate estimated orientation of the antenna structure directly from differences in carrier phase angle measurements of incoming GNSS carrier signals at the antennas, determine the angles of incidence of the respective GNSS satellite signals based on positions of respective satellites and the estimated orientation of the antenna structure, enter the phase map using the angles of incidence and retrieve associated carrier phase difference error values, and utilize the associated carrier phase difference error values to correct the estimated orientation to produce an updated orientation; and the one or more processors further configured to re-enter the phase map to calculate a new updated orientation, utilizing updated angles of incidence, until a change in the new updated orientation is less than an error gradient associated with the phase map. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of operating a GNSS receiver comprising:
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receiving incoming GNSS signals at two or more antennas on an antenna structure, each antenna being spaced apart from at least one neighboring antenna by an ultra short baseline that is less than one wavelength of a carrier of the GNSS signals, measuring carrier phase angles of the GNSS signals at the antennas and calculating one or more carrier phase differences directly from the carrier phase angle measurements, calculating estimated orientation of the antennas from the carrier phase differences, using the calculated estimated orientation and a position of a satellite to determine angles of incidence of incoming GNSS signals, using the angles of incidence to enter a phase map or table to retrieve associated carrier phase difference error values that include line biases associated with operation of the GNSS receiver and calculated for respective pairs of antennas based on phase difference values, correcting the calculated carrier phase differences based on the carrier phase difference error values, correcting the estimated orientation based on the corrected phase differences to produce an updated orientation, and re-entering the phase map, utilizing updated angles of incidence, to retrieve the associated carrier phase difference error values to calculate a new updated orientation until a change in the new updated orientation is less than an error gradient associated with the phase map. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification