Ground Control

Andrew BourgeoisAaron Minard

Background

http://streamsurfers.netfirms.com/faq/faq0001_how_it_works.htm

Data transmitted at the speed of light in a straight line.

Satellites used to avoid curve of the earth

If not geostationary, moves across the sky.

SatPC32

Calculates the tracks of earth orbiting satellites.

Calculations are based on the SGP4/SDP4 model, highly accurate.

Simplified General Perturbations Satellite Orbit Model 4 (NASA/NORAD)

SatPC32

CubeSat Satellite

Developed by Cal Poly and Stanford University 10cm3 and has a mass of 1kg Powered by photovoltaic cells and rechargeable

batteries Usually launched piggyback to commercial

satellites Costs $30,000 to $50,000 to build and the same

amount to ride piggybacked on a commercial satellite.

Problem

Track a low orbit satellite from horizon to horizon

Move a 3 meter satellite dish

Interface to SatPC32

Solutions

Gears and motor

Motor controllers to interface with SatPC32

Digital Encoders to control position of the dish

Use/Modify existing designs for elevation and azimuth control

System Diagram

Micro-controller

MC

MC

A E

Limit SwitchRS232 (2x)

Analysis

COMING SOON

Analysis

Horse-Power

deg Gear Ratio 2 3 4 5 6 7 8 9 10

5   0.262501 0.175 0.13125 0.105 0.0875 0.075 0.065625 0.058333 0.0525

10   0.13125 0.0875 0.065625 0.0525 0.04375 0.0375 0.032813 0.029167 0.02625

15   0.0875 0.058333 0.04375 0.035 0.029167 0.025 0.021875 0.019444 0.0175

20   0.065625 0.04375 0.032813 0.02625 0.021875 0.01875 0.016406 0.014583 0.013125

25   0.0525 0.035 0.02625 0.021 0.0175 0.015 0.013125 0.011667 0.0105

30   0.04375 0.029167 0.021875 0.0175 0.014583 0.0125 0.010938 0.009722 0.00875

35   0.0375 0.025 0.01875 0.015 0.0125 0.010714 0.009375 0.008333 0.0075

40   0.032813 0.021875 0.016406 0.013125 0.010938 0.009375 0.008203 0.007292 0.006563

45   0.029167 0.019444 0.014583 0.011667 0.009722 0.008333 0.007292 0.006481 0.005833

Elevation

Azimuth

ElectricalPosition Encoders

AC

MCMC L.S.

24Vdc FUSE

5Vdc

Micro-controller

A

E

L.S.

FUSE

FUSE

Programming

Material Costs

Mechanical Materials

Steel

2" x 2" x 12' Square Tube $54.48

1" x 1" x 8' Square Tube $17.28

24" x 24" x 1/4" Steel Plate $129.56

1" x .12"th x 6" Round Tube $64.71

1" x 6' Round Stock $55.97

total $322.00

Questions?