andrew bourgeois aaron minard. background satellite tracking satpc32 problem statement solution...
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Ground Control
Andrew BourgeoisAaron Minard
Contents
Background Satellite Tracking SatPC32
Problem Statement Solution Mechanical Design System Diagram Electrical Design Software Schedule Budget
Background
VTC developing Cubesat, transmits data
Have to follow Cubesat to receive data
Existing 3-meter parabolic dish antenna
Low orbit satellite revolves around earth in minutes, seen for short time per orbit
Many existing solutions EGIS Bi-axial antenna positioning system BIG-RAS Azimuth and Elevation Rotator
EGIS Rotor and Control
Equipment-Gesellschaft für Internationale Elektronik Systeme
Cost: Software $400 Data Interface $1,100 Hardware $2,700 (EL-40°, AZ-180°) Extension $2,200 (EL-90°, AZ-360°) Rotor Hardware Mount $400 Satellite Dish Mount $400
▪ Total $7,200
SatPC32
A free software available online for tracking satellites. Updates on screen and controls rotor to point to position satellite
Uses orbit of satellite and observer position
Many types of rotors to select for output
Uses Serial port or Parallel port on PC
SatPC32
Screen Shot of SatPC32 in use
WinListen predicts path
Problem
Track a low orbit satellite such as a CubeSat from horizon to horizon is as little as 30 seconds180°/30 seconds=6°/sec
Move a 3 meter satellite dish 360° Azimuth (left/right) 90° Elevation (up/down)
Interface to PC running SatPC32
Integrate/improve previous design
Solution
Gears and motors, motor controllers Freescale Coldfire 32-bit Microcontroller Serial interface with SatPC32 using EGIS
controls and a serial port Position sent as ASCII Characters :P AZ=123.45 :P EL=009.87
Magnetic Encoders measure position of dish
Use/Modify existing designs for elevation and azimuth control
Mechanical Stuffffffffffffffffff Maybe some Azimuth (talk about using last years
stuff that was good?)
Maybe a whole slide summarizing last years model and then discussing what we liked (Azimuth) and what we thought needed improvement (Elevation)
We liked work gears for both… why? (speed)
Discuss around here about the wind force calculations….? Angular acceleration…. ?
Position Sensing
Specified previously 1° step size = at least nine bit
resolution29 = 512 steps 360 deg/512 steps = .7 deg/step
6°/sec = 1 rpm(6°/sec)(60sec/1min)(1rev/360deg)
Magnetic shaft encoder Absolute position sensing Small size, large operating temperature range Analog output from 10-bit DAC
▪ 1024 steps or .35°/step
System Diagram
Micro-controller
EL - Motor
ControllerAZ -
Motor Controlle
r
Limit Switches
RS232
SatPC32
PositionEncoders
Electrical Flow
Position Encoders
AC
Motor Controlle
r
Motor Controlle
r
12Vdc10Amp
FUSE
5Vdcregulat
or
Micro-controller
A
E
Circuit Protectio
n
12Vdc10Amp
FUSE
PC Running SatPC32
Limit Switc
h
Limit Switc
h
Software (Microcontroller)
Decide where to turn, how fast
Read new position from serial port Stores values when they come in
Read actual position from encoders Measure periodically
Always checking limit switches If ever activated, stop motors
Controller(Set
Outputs)
New Serial
?
Check Encoder
s?
ReadSerial
Read Encoders
Micro Controller Connections
Check Serial Code
Schedule Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 Week 10 Week 11 Week 12 Week 13Week 14
Mechanical
Final Mounting of all
Electrical
Coldfire Peripheral Boards
Power Supply Wiring
Motor Drivers to DC Motors
Sensor Wiring/Positioning
Software
SatPC32 Research
Serial Port Code
Encoder Code
Motor Controller Code
Code Integration
Testing
Schedule
Week1 Week2 Week3 Week4 Week5 Week6 Week7 Week8 Week9 Week10 Week11 Week12 Week13 Week14
Mechanical
Final Mounting
Electrical
Coldfire Peripheral Boards
Power Supply Wiring
Motor Drivers to DC Motors
Sensor Wiring/Positioning
Software
SatPC32 Research
Serial Port Code
Encoder Code
Motor Controller Code
Code Integration
Testing
Budget
Questions?
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