초록 ▼

An improved GPS Attitude Receiver for spacecraft uses concurrent line-bias estimates derived from GPS signals for attitude determination. Attitude determination is obtained from GPS measurements by an interactive solution of the known "Attitude Master Equation", using RF differential phase measureme

An improved GPS Attitude Receiver for spacecraft uses concurrent line-bias estimates derived from GPS signals for attitude determination. Attitude determination is obtained from GPS measurements by an interactive solution of the known "Attitude Master Equation", using RF differential phase measurements and calibrated parameters of baseline vectors and line-biases. A "weighted fit error" W, is derived from the sum squared of discrepancies between predicted and actual measurements, weighted by measurement variances. By minimizing W, the line-bias estimations obtained give more current data including thermal effects and eliminate separate ground calibration tests.

대표청구항 ▼

[ What is claimed is:] [1.] A system for attitude determination in a spacecraft using GPS signals to obtain differential phase measurements and using concurrent line-bias estimates, comprising:antenna means on the spacecraft, including a Master Antenna, for receiving GPS signals;means, responsive to

[ What is claimed is:] [1.] A system for attitude determination in a spacecraft using GPS signals to obtain differential phase measurements and using concurrent line-bias estimates, comprising:antenna means on the spacecraft, including a Master Antenna, for receiving GPS signals;means, responsive to said received GPS signals, for performing a line of sight, LOS, calculation on the system position parameters, x-y-z, derived from said received GPS signals, and producing LOS signals indicative thereof;update means, responsive to said LOS signals, for performing an attitude update processing and producing an attitude transformation signal, A;baseline means for determining the baseline geometry of the locations of said antenna means and producing signals indicative of the baselines, Xj;means for producing signals indicative of integer wavelengths in the differential range, kij, derived from factors comprising initial integer resolutions, line bias estimations, "wraparound" from phase monitoring, and an integrity check;means, responsive to GPS signals received by said antenna means, for producing signals indicative of differential phase measurements, .DELTA..phi.ij;means, responsive to said differential phase measurements, .DELTA..phi.ij, for producing attitude correction and attitude rate correction signals, .delta..crclbar., .delta..crclbar.*, .delta..phi., .delta..phi.*, .delta..psi., .delta..psi.*, including a line bias correction .DELTA..beta.j, said means comprising:means for performing a weighted least squares fit, using "weighted fit error" W derived from the "Attitude Master Equation", on signals input thereto including:said differential phase measurements signals, .DELTA..phi.ij;said attitude transformation signal, A;said baseline signals, Xj; andsaid signals indicative of integer wavelengths in the differential range, kij; andfor producing said line bias correction .DELTA..beta.j to provide a concurrent line bias estimate; andmeans for inputting said attitude correction and attitude rate correction signals, .delta..crclbar., .delta..crclbar.*, .delta..phi., .delta..phi.*, .delta..psi., .delta..psi.*, including a line bias correction .DELTA..beta.j, to said update means for combining with said LOS signals, to obtain an output indicative of attitude and attitude rate in pitch, roll, and yaw, .crclbar., .crclbar.*, .phi., .phi.*, .psi., .psi.*, using concurrent line-bias estimates.