Path: SC/Sensor
% A dual scan Earth Sensor model
This function models a dual scan earth sensor. It has two sensors at
different roll angles. It measures the chordwidth given by the two scans
and then uses that to compute roll and pitch. The offset of the scan from
vertical axis determines pitch. It also computes a standard, the average
of the two so that if one scan is off the Earth it can still produce
roll and pitch angles. It updates d each time it is called. The standard
chord is updated sequentially wih each sample.
Type PlanetSensorDualScan for a demonstration of a spacecraft in
geosynchronous orbit.
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Form:
d = PlanetSensorDualScan;
[roll, pitch, d] = PlanetSensorDualScan(r, q, d)
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Inputs
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r (3,:) Position vector in the ECI frame (km)
q (4,:) Quaternion ECI to Body
d (.) Sensor data structure
.cant (2,1) Cant angle from rotation axis (rad)
.sC (1,1) Standard chord (rad)
.uB (3,1) Boresight vector
.uS (3,1) Scan vector
.aP (1,1) Planet radius
.sig (1,1) 1 sigma chordwidth noise
.useScan (2,1) true if use that scan
.valid (1,:) true if data is valid
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Outputs
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roll (1,:) Roll (rad)
pitch (1,:) Pitch (rad)
d (.) Sensor data structure
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AerospaceUtils: Coord/RollPitchToQECI Orbit: OrbitMechanics/RVOrbGen Common: Graphics/Plot2D Common: Quaternion/QForm Math: Linear/Cross Math: Linear/Mag Math: Linear/Unit
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