Path: SpacecraftEstimation/OpticalNavigation
% Demonstrate optical navigation in earth geosynchronous transfer orbit. Uses an earth sensor and a star sensor. The earth sensor measures the earth chord. The star sensor measures an angle from the nadir vector to the star. The gravity model is point mass without any perturbations or disturbances such as solar or aerodynamics. It is interesting to try the sim without the update step. If you do this you will find that the error gets extremely large after 4 orbits. This happens because the covariance grows and eventually at perigee, the mean orbit will be hyperbolic. The star sensor assumes that it can see multiple stars. This can be accomplished by a wide field of view sensor or by an articulated sensor. This demo uses the new UKF framework with separate propagate and measurement update functions. Things to try: 1. Change the orbit 2. Change the sensor noise 3. Change the star vector 4. Add disturbances. 5. Use only the earth chord measurement 6. Turn off the update step 7. Vary the initial covariances Since version 2014.1 -------------------------------------------------------------------------- % -------------------------------------------------------------------------- Copyright (c) 2014 Princeton Satellite Systems, Inc. All rights reserved. --------------------------------------------------------------------------
AC: ACData/ACTConstants Orbit: OrbitCoord/RPRA2AE SC: BasicOrbit/CP2I SC: BasicOrbit/E2Nu SC: BasicOrbit/El2RV SC: BasicOrbit/M2E SC: BasicOrbit/M2EApp SC: BasicOrbit/M2EEl SC: BasicOrbit/M2EHy SC: BasicOrbit/M2Nu SC: BasicOrbit/M2NuPb SC: BasicOrbit/Period SC: BasicOrbit/RHSOrbit SC: SCData/sCTConstants SpacecraftEstimation: SensorMeas/MeasEarthChord SpacecraftEstimation: SensorMeas/MeasNadirStar Common: CommonData/Constants Common: CommonData/SwooshWatermark Common: CommonData/xSplashSmall Common: Database/Constant Common: Estimation/KFInitialize Common: Estimation/UKFPredict Common: Estimation/UKFUpdate Common: Estimation/UKFWeight Common: General/CellToMat Common: General/DeleteCell Common: General/DispWithTitle Common: General/MatToCell Common: General/Watermark Common: Graphics/NewFig Common: Graphics/Plot2D Common: Graphics/PltStyle Common: Graphics/TimeLabl Math: Integration/RK4 Math: Linear/Dot Math: Linear/DupVect Math: Linear/Mag Math: Linear/Unit Math: Trigonometry/CosD Math: Trigonometry/SinD
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