Investigation of Multiple Orthogonal SunSensor

sunsensor

1. INVESTIGATION AND DEVELOPMENT OF
MULTIPLE ORTHOGONAL SUN SENSORS
AND ESTABLISHMENT OF ITS CALIBRATION
PROCEDURES
Hilmi Sanusi
Dept. of Electrical, Electronic and System Engineering,
Universiti Kebangsaan Malaysia

2. Table of Content
Introduction
Background of the research
Current research
Methodology
Investigation
Development
Concluding remark

3. Introduction
Why –Ask Why?
All satellites need attitude reference and their accuracy are a
luxury
Simple attitude algorithm needs at least two sensors
Sun sensor usually couple with Magnetometer and Horizon
sensors but both sensors are noisy and inaccurate because of
uneven earth surface and disruption to the geomagnetic field
during high solar activity.
Problem occurs during high solar activity where magnetometer is
very noisy that cause inaccurate attitude; thus need more robust
sensor

4. Introduction –Objective of the Research
To design, develop and test the MOSS and make further
enhancement to the current known developed sensor as
an experimental attitude sensor
To develop a space qualify test and calibration procedure
for the sensor -MOSS

5. Background of the research
Continuation of previous method developed for ORYX-Sat but have
no chance of developing the sensor
Useful for NEqO LEO satellites –target –RAZAK-Sat and its class
The developed method is the only method that use only sun sensor
for attitude determination and does not influence by geomagnetic
field noise
Research opportunity is in imitating the same development at
SUNSpace to build, test and develop the sensor and establish its
calibration procedure
Develop a design procedure that is practiced in the aerospace
industry

6. Research Procedure
Development of method: spin axis attitude determination
Finding sensor characteristic
Development of electronic interfaces
Development of prototype sensors: at least 3 orthogonal
sensors
Development of test procedures
Development of calibration process
Construct engineering model

7. Current research status
Developed an attitude determination process using Method
of spin axis determination from body rotated sun vector
using Quaternion.
Tested with real satellite data –raw sun sensor data with
attitude reference
Evaluate the characteristic of the PSD sensor
Developed necessary electronics interface for the sensors
Evaluating various microcontroller

8. Methodology –Investigation
Full investigation of the develop sensor
Develop a pair of orthogonal sensor using PSD (Position
Sensitive Device) develop by SiTek
Develop the necessary electronics. A precision resistor will
be employed for I-V conversion
Develop a stable and low noise power supply for the PSD
Test the pair of orthogonal sensor on a rate bench –
develop it or buy it?How? Where? How long? etc

9. Methodology -Development
Develop the MOSS in octagonal configuration –
does it needs augmentation??
Sun sensor

10. Methodology –Investigation
Test the develop method
Get the sun vector from an orthogonal PSD sensor
need calibration, of course!!!
Get the spin axis by taking cross product of both
sensors.
The spin axis is the Euler axis for the Quaternion and
the direction of the sun w.r.t x-yplane is the rotation
angle^
sin cos
cos sin
sin
b
s
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








11. Methodology -Development
Develop a calibration technique for the sensor
Calibrate the mounted sensor
Performed a radiation test. Ask permission to do an X-
ray on the MOSS. Cumulative effect is sufficient but not
enough.
Look for sensors and electronics anomaly. Look for cure.
All development must follow space qualify procedure

12. Concluding Remark
A strategic partner to put the sensor in space as a piggy back
ATSB is free, else MONEY!!!
Create an astronautic engineering environment in the local
university.
Advancement of sensors are the cutting edge in satellite
technology.
Ready for SALE!!! Opps not yet. This is an experimental
sensor. Put it on board for future Malaysian Satellite.
Microsat, picosat and cansat are no longer exciting except with
new breed of sensors