AAU-Cubesat Ground Station Software Overview - CRN
AAU-Cubesat Ground Station Software Overview - CRN
AAU-Cubesat Ground Station Software Overview - CRN
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4 CHAPTER 1. GENERAL SYSTEM OVERVIEW<br />
Antenna Controller: The YAESU G-5500 antenna controller amplifies control signals from the computer<br />
and applies the control to the antenna rotor. Further it measures the current angles (azimuth and<br />
elevation) of the antennas using potentiometers. These signals are feed back to the server computer.<br />
MX909 board: Is a MCB-167 evaluation board that communicates with the server using a serial connection<br />
and implements the protocol needed to drive the MX909 modem that is attached to the evaluation<br />
board.<br />
Radio: The radio is the ICOM 910H that is used to modulate/demodulate the baseband signal onto the<br />
carrier frequency. This frequency is controlled by the server in order to account for the doppler effect<br />
and the baseband signal is sent to or received from the modem board<br />
Server: The server runs on a standard PC and maintain the whole system, i.e. it calculates control signals<br />
to the antenna controller and doppler shift for the radio. Further it implements the AX25 protocol and<br />
decodes incoming information and stores it in a central database. Finally it handles communication<br />
with the satellite operators.<br />
Operator: Operates the satellite from a computer that need not to be the server, but could be any computer<br />
attached to the internet. From a client program it is possible to control the server operations and send<br />
commands/data directly to the satellite if it is in range.<br />
Surfer: Is a public user that is able to read statistics about the satellite from a computer anywhere on the<br />
internet. These informations are taken from the database and presented to the user through a web-page<br />
programmed in the PHP web scripting language.<br />
1.2 <strong>Software</strong> Diagram<br />
The diagram depicted in figure 1.2 shows the various pieces of software that make up the groundstation.<br />
Ovals are processes and square boxes are terminators and/or sources of data.<br />
Antenna<br />
(DT2811)<br />
Radio<br />
Modem<br />
Board<br />
Antenna<br />
tracking<br />
AX25<br />
Protocol<br />
NORAD<br />
Predict<br />
Server<br />
Net user<br />
Client<br />
Presentation<br />
Operator<br />
Database<br />
Figure 1.2: Diagram of software implementing the ground station<br />
Again we will briefly summarize the functionality of the blocks focusing on the processes:
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