GNSS signal processing methods and apparatus with ambiguity convergence indication
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 comprising a float ambiguity for each received frequency of the GNSS signals, each float ambiguity constituting a real number estimate of 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, the filter estimating a float value for each float ambiguity of the state vector and covariance values associated with the state vector;
assigning integer values to at least a subgroup of the estimated float values to define a plurality of integer ambiguity candidate sets;
obtaining a weighted average of the candidate sets;
determining a formal precision value based on covariance values of the filter, the formal precision value being a measure for an achievable precision;
determining an achieved precision value of the weighted average;
comparing the achieved precision value with the formal precision value to obtain a convergence value; and
indicating a convergence of the determination of the state vector.
1 Assignment
0 Petitions
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 (2120). The observations are fed to a filter having a state vector comprising a float ambiguity for each received frequency of the GNSS signals (2140). The filter estimates a float value for each float ambiguity of the state vector and co-variance values associated with the state vector. Integer values are assigned to at least a subgroup of the estimated float values to define a plurality of integer ambiguity candidate sets (2160). A weighted average of the candidate sets is formed (2200). A formal precision value based on covariance values of the filter is determined (2205), the formal precision value being a measure for an achievable precision. An achieved precision value of the weighted average is determined (2210). The achieved precision value is compared with the formal precision value to obtain a convergence value (2215). A convergence of the determination of the state vector is indicated (2218). 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.
58 Citations
49 Claims
-
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 comprising a float ambiguity for each received frequency of the GNSS signals, each float ambiguity constituting a real number estimate of 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, the filter estimating a float value for each float ambiguity of the state vector and covariance values associated with the state vector; assigning integer values to at least a subgroup of the estimated float values to define a plurality of integer ambiguity candidate sets; obtaining a weighted average of the candidate sets; determining a formal precision value based on covariance values of the filter, the formal precision value being a measure for an achievable precision; determining an achieved precision value of the weighted average; comparing the achieved precision value with the formal precision value to obtain a convergence value; and indicating a convergence of the determination of the state vector. - 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, 49)
-
-
24. 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 comprising a float ambiguity for each received frequency of the GNSS signals, each float ambiguity constituting a real number estimate of 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, the filter estimating a float value for each float ambiguity of the state vector and covariance values associated with the state vector; a processing element adapted to assign integer values to at least a subgroup of the estimated float values to define a plurality of integer ambiguity candidate sets; obtain a weighted average of the candidate sets; determine a formal precision value based on covariance values of the filter, the formal precision value being a measure for an achievable precision; determine an achieved precision value of the weighted average; compare the achieved precision value with the formal precision value to obtain a convergence value; and indicate a convergence of the determination of the state vector. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48)
-
Specification