Engineering Ground Station
Documentation for the satellite tracking ground station on the roof of the UCF Engineering I (ENG1) building. Collaborative project with ARC@UCF.
Last updated
Documentation for the satellite tracking ground station on the roof of the UCF Engineering I (ENG1) building. Collaborative project with ARC@UCF.
Last updated
The ARC@UCF currently operates uses a Yaesu G-5500 rotator controller. This controller has a computer interface port which allows their GS-232B computer interface unit to automatically point the rotator at a target as instructed by a computer. The GS-232B is very expensive so many have implemented their own such as the .
KSC is currently developing a custom computer interface unit to restore satellite tracking functionality to ARC's ground station. This open source interface is build around a Raspberry Pi Pico and will ultimately include firmware, a PCB, and enclosure.
This custom option was chosen to build experience with the Pico, train members on PCB design, and to have a simpler code base... most of the K3NG code resides in a single 22,000 line .ino file!
The G-5500 instruction manual briefly describes the external control interface. The DIN cable colors are specific to our cable breakout, I am not sure if they are standard.
1
Brown
Provides 2 to 4.5 VDC corresponding to 0° to 180° (elevation)
2
Green
Connect to Pin 8 to rotate right (clockwise)
3
White
Connect to Pin 8 to rotate up
4
Blue
Connect to Pin 8 to rotate left (counterclockwise)
5
Yellow
Connect to Pin 8 to rotate down
6
Black
Provides 2 to 4.5 VDC corresponding to 0° to 450° (azimuth)
7
Red
Provides DC 13 V to 8 V at up to 100 mA
8
Gray
Common ground
From our testing, we have found the azimuth voltage to vary from 0.22V (0°) to 4.23V (450°) and the elevation voltage to vary from 0.20V (0°) - 2.20V (90°).
We had hoped that switching pins on the Pico between low and high or input (low impedance) mode, we could create the active low control signals expected by the G-5500 without external circuitry. Initial testing was unsuccessful so a circuit utilizing an NPN transistor was tested but that also did not work.
The only difference between our test circuit and an example K3NG rotator diagram is a capacitor between the control line and ground just before the transistor. I am not sure why this would make a difference but it will be tested.
A collection of useful links relevant to this project.
