Observability of satellite launcher navigation with INS, GPS, attitude sensors and reference trajectory

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Authors
  1. Beaudoin, Y.
  2. Desbiens, A.
  3. Gagnon, E.
  4. Landry, R.J.
Corporate Authors
Defence Research and Development Canada, Valcartier Research Centre, Quebec QC (CAN)
Abstract
The navigation system of a satellite launcher is of paramount importance. In order to correct the trajectory of the launcher, the position, velocity and attitude must be known with the best possible precision. In this paper, the observability of four navigation solutions is investigated. The first one is the INS/GPS couple. Then, attitude reference sensors, such as magnetometers, are added to the INS/GPS solution. The authors have already demonstrated that the reference trajectory could be used to improve the navigation performance. This approach is added to the two previously mentioned navigation systems. For each navigation solution, the observability is analyzed with different sensor error models. First, sensor biases are neglected. Then, sensor biases are modelled as random walks and as first order Markov processes. The observability is tested with the rank and condition number of the observability matrix, the time evolution of the covariance matrix and sensitivity to measurement outlier tests. The covariance matrix is exploited to evaluate the correlation between states in order to detect structural unobservability problems. Finally, when an unobservable subspace is detected, the result is verified with theoretical analysis of the navigation equations. The results show that evaluating only the observability of a model does not guarantee the ability of the aiding sensors to correct the INS estimates within the mission time. The analysis of the covariance matrix time evolu
Keywords
Observability;INS;GPS;reference trajectory
Report Number
DRDC-RDDC-2017-P110 — External Literature
Date of publication
01 Nov 2017
Number of Pages
16
DSTKIM No
CA045496
CANDIS No
805910
Format(s):
Electronic Document(PDF)

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