PressureKF:

Path: SpacecraftEstimation/UKF

% Demonstrate a fuel mass Kalman filter for a blowdown system.
 In a blowdown system, the fuel is pressurized by a gas, such as
 helium. As fuel is consumed the gas expands into the empty volume
 and the pressure decreases. The estimator 
 uses a pulsewidth model and a pressure measurement. The pressure
 measurements on a spacecraft are generally low resolution, typically
 8 bits over the entire pressure range (of 350 psi to 100 psi.)
 Every time a thruster fires, the model computes the fuel used
 based on a model of fuel consumption versus pulsewidth. This is 
 the dynamical model. The measurement of pressure is then 
 incorporated into the estimate using an Unscented Kalman Filter
 (UKF). The UKF can use a nonlinear measurement and plant (dynamics)
 model directly without any linearization.

 The script computes a random pulsewidth from 0 to 8 seconds in 
 length when a second random number between 0 and 1, is greater than
 0.95.

 The pressure measurement has 12 bits resolution and random noise.

 The script plots true pressure, fuel mass estimated errors, pulsewidth
 and the pressure measurement.

  ------------------------------------------------------------------------
  See also NQuant, Plot2D, UKF, BloDownMass, UE, BloDown, MolWt2R
  ------------------------------------------------------------------------
%
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   Copyright (c) 2006 Princeton Satellite Systems, Inc. 
   All rights reserved.
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Children:

Propulsion: Gas/BloDownMass
SC: Actuator/BDDesign
SC: Actuator/BloDown
SC: Environs/MolWt2R
Common: CommonData/SwooshWatermark
Common: Control/NQuant
Common: DemoFuns/GXUKF
Common: DemoFuns/RHSUKF
Common: Estimation/SigmaPointsChol
Common: Estimation/UKF
Common: General/CellToMat
Common: General/MatToCell
Common: General/Watermark
Common: Graphics/NewFig
Common: Graphics/Plot2D
Common: Graphics/PltStyle
Math: Integration/RK4

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