GNSS Signal Processing Methods and Apparatus with Ambiguity Selection
First Claim
1. Method to estimate parameters derived from global navigational satellite system (GNSS) signals useful to determine a position, comprisingobtaining observations of a GNSS signal from each of a plurality of GNSS satellites;
- feeding the observations to a filter having a state vector at least comprising a float ambiguity for each received frequency of the GNSS signals, each float ambiguity constituting a real number estimate associated with an integer number of wavelengths of the GNSS signal between a receiver of the GNSS signal and the GNSS satellite from which it is received, and the filter being for estimating a float value for each float ambiguity of the state vector;
selecting a subset of the ambiguities of the state vector;
assigning integer values to the estimated float values of the float ambiguities of the subset to define a plurality of candidate sets;
determining a quality measure for each of the candidate sets; and
forming a weighted average of the candidate sets.
1 Assignment
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Accused Products
Abstract
Methods and apparatus are provided for estimating parameters, i.e. ambiguities, derived from GNSS signals. Observations of a GNSS signal from each of a plurality of GNSS satellites are obtained (4120). The observations are fed to a filter having a state vector at least comprising a float ambiguity for each received frequency of the GNSS signals, each float ambiguity constituting a real number estimate associated with an integer number of wavelengths of the GNSS signal between a receiver of the GNSS signal and the GNSS satellite from which it is received, and the filter being for estimating a float value for each float ambiguity of the state vector (4140). A subset of float ambiguities of the state vector is selected (4150). Integer values are assigned to the estimated float values of the float ambiguities of the subset to define a plurality of integer ambiguity candidate sets (4160). A quality measure is determined for each of the candidate sets. A weighted average of the candidate sets is formed (4200). Ambiguities of the weighted average can be used in subsequent operations to aid in determining a position of the receiver or can be used to prepare data, e.g., in a network processor that can be used to augment position information of a rover.
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Citations
54 Claims
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1. Method to estimate parameters derived from global navigational satellite system (GNSS) signals useful to determine a position, comprising
obtaining observations of a GNSS signal from each of a plurality of GNSS satellites; -
feeding the observations to a filter having a state vector at least comprising a float ambiguity for each received frequency of the GNSS signals, each float ambiguity constituting a real number estimate associated with an integer number of wavelengths of the GNSS signal between a receiver of the GNSS signal and the GNSS satellite from which it is received, and the filter being for estimating a float value for each float ambiguity of the state vector; selecting a subset of the ambiguities of the state vector; assigning integer values to the estimated float values of the float ambiguities of the subset to define a plurality of candidate sets; determining a quality measure for each of the candidate sets; and forming a weighted average of the candidate sets. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 54)
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26. Apparatus to estimate parameters derived from global navigational satellite system (GNSS) signals useful to determine a position, comprising
a receiver adapted to obtain observations of a GNSS signal from each of a plurality of GNSS satellites; -
a filter having a state vector at least comprising a float ambiguity for each received frequency of the GNSS signals, each float ambiguity constituting a real number estimate associated with an integer number of wavelengths of the GNSS signal between a receiver of the GNSS signal and the GNSS satellite from which it is received, and the filter being for estimating a float value for each float ambiguity of the state vector; a processing element adapted to select a subset of float ambiguities of the state vector; assign integer values to the estimated float values of the float ambiguities of the subset to define a plurality of integer ambiguity candidate sets; determine a quality measure for each of the candidate sets; and form a weighted average of the candidate sets. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52)
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53. (canceled)
Specification