Path: SpacecraftEstimation/AttitudeEstimation
% Simulate attitude determination for a momentum bias spacecraft. At this point we do not include any real actuators or sensors. The orbit is modeled and the spacecraft controls errors with respect to the LVLH frame. ------------------------------------------------------------------------- Specification ------------------------------------------------------------------------- Ours is a Gravity gradient stabilization satellite with two analog medium sun sensors and one magnetometer for attitude knowledge. We are using Magnetorquer rods as our controller which is basically a PD controller and also a small momentum wheel with angular momentum of 1 Nms and with constant speed on the pitch axis to counter the external disturbance. The nadir pointing accuracy required is < 5 degrees and the attitude errors in all the three axes should be less than 3 degrees. The inertia in the three directions are Ix=120, Iy=120 and Iz=1.3. The orbit radius is 6718+352 Kms (low earth orbit satellite). The inclination is 28.45 deg. The damping ratios and natural frequencies are: Tach loop: zeta = 0.7621 wN= 0.5 Pitch and Roll loop: zeta = 0.7621 wN = 0.009 Yaw loop: zeta = 1.0 wN = 0.15 ------------------------------------------------------------------------- See also IC623X3, PDDesign, PIDesign, QForm, QLVLH, QMult, QPose, Constant, NPlot, Plot2D, TimeGUI, RK4, JD2000, SunMagAttDet, TOrbit, RVFromKepler, MagField, SunV1, FPSensors ------------------------------------------------------------------------- % -------------------------------------------------------------------------- Copyright 1999, 2016 Princeton Satellite Systems, Inc. All rights reserved. -------------------------------------------------------------------------- Since version 5.5 (2003) 2016.1 Switch to newer IGRF11 model (from 1995 data) for the Earth --------------------------------------------------------------------------
AC: ACData/ACTConstants AerospaceUtils: Coord/ECIToEF AerospaceUtils: Coord/QLVLH SC: BasicOrbit/RVFromKepler SC: Environs/MagField SC: Environs/MagFieldData SC: Environs/MagFieldPlanet SC: Environs/ReadMagField SC: Ephem/SunV1 SC: SCData/sCTConstants SC: SCMat/IGRF11 SC: Sensor/FPSensors SC: Sensor/U2Pix SpacecraftEstimation: AttitudeEstimation/EKFSSG SpacecraftEstimation: AttitudeEstimation/SunMagAttDet Common: CommonData/Constants Common: CommonData/SwooshWatermark Common: CommonData/xSplashSmall Common: Control/C2DZOH Common: Control/C2DelZOH Common: Control/FResp Common: Control/GND Common: Control/GSS Common: Control/ND2SS Common: Control/PDDesign Common: Control/PIDesign Common: Control/S2Damp Common: Control/SS2ND Common: Control/SizeABCD Common: Control/TrnsZero Common: Control/WPZ Common: Control/WReson Common: Control/ZFresp Common: Database/Constant Common: GUIs/TimeGUI Common: General/CellToMat Common: General/CloseIfHandle Common: General/DeBlankLT Common: General/DeleteCell Common: General/ListCases Common: General/MatToCell Common: General/Watermark Common: Graphics/LogLimit Common: Graphics/NewFig Common: Graphics/Plot2D Common: Graphics/Plot3D Common: Graphics/PltStyle Common: Graphics/TextS Common: Graphics/TimeLabl Common: Graphics/TitleS Common: Graphics/XLabelS Common: Graphics/YLabelS Common: Graphics/ZLabelS Common: MassProperties/IC623X3 Common: Quaternion/Mat2Q Common: Quaternion/Q2Mat Common: Quaternion/QForm Common: Quaternion/QMult Common: Quaternion/QPose Common: Time/DTSToDTA Common: Time/Date2JD Common: Time/JD2000 Common: Time/JD2T Common: Time/T2JD Common: Transform/Cart2Sph Math: Analysis/PGauss Math: Analysis/SCHarm Math: Integration/RK4 Math: Linear/ColCompR Math: Linear/Cross Math: Linear/DelLZ Math: Linear/IsZero Math: Linear/Mag Math: Linear/RowCompU Math: Linear/Skew Math: Linear/Unit Math: Trigonometry/CosD Math: Trigonometry/SinD
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