v2.0 C2C QSG - alanbjohnston/CubeSatSim GitHub Wiki

This is the Command and Control Quick Start Guide (QSG) for the CubeSatSim

Note: to do Command and Control, you need to have a v1.3.2 or v2.0 CubeSatSim with the USB soundcard. For details on how to wire and install it, see Command and Control

Satellite Command and Control refers to the ability to connect, usually over radio, with a satellite and upload commands, settings, schedule operations and experiments, and other functions. For demonstrations, the CubeSatSim has a pushbutton that can be used to change modes or shut down.

The Beta v1.3.2 CubeSatSim can now support radio Command and Control using a FM transmitter in the UHF band, sending either a carrier signal, or DTMF tones or APRS packets.

Carrier (or squelch) Command and Control does not require any additional hardware, as it uses the squelch pin on the FM transceiver to detect a command.

Note: Command and Control involves transmitting in the Ham Radio 70cm band which requires an amateur radio license. Before doing this, ensure you have your license and comply with all local rules and regulations. If you live in the USA, here is some information: https://www.arrl.org/getting-licensed

The default frequency which you should transmit on for Command and Control is 435 MHz. You can change this frequency by logging into your Pi Zero 2 and typing CubeSatSim/config -F and changing the receive frequency of the CubeSatSim.

If you tune your Ground Station to this frequency, you should see your Command and Control transmissions. For example, the OpenWebRX Web SDR on the Pi Ground Station will show both the CubeSatSim transmit signal at the default 434.9 MHz and any Command and Control signals at 435 MHz.

By default, Command and Control is OFF on the CubeSatSim. There are two ways to turn it on or off:

• Using the pushbutton - press and hold the pushbutton until it goes through its full sequence: a series of short blinks, some longer blinks, then some even longer blinks. At this point, you can release the pushbutton. This will toggle the state. That is, if Command and Control was On, it will turn off. If it was off, it will turn on.
• Using a command line on your Pi Zero 2. You will need to log into your Pi Zero 2, such as with ssh, and then type the command CubeSatSim/config -T and then follow the prompts to turn it on or off.

When turned on, Command and Control has three modes:

• Carrier Command and Control. In this mode, the CubeSatSim is just listening for a carrier signal on the receive frequency. The squelch setting on the FM Transceiver set with the CubeSatSim/config -q will determine the sensitivity. If a carrier is detected, the CubeSatSim will move to the next mode and the Green Power LED will blink the number of times of that mode. The sequence is APRS -> FSK -> BPSK -> SSTV -> CW -> APRS This mode is the simplest, but it can produce false triggers.

• DTMF Command and Control. In this mode, the CubeSatSim is listening for DTMF key presses followed by the pound (hash) sign #. The DTMF number corresponds to the mode number. The Green Power LED will blink with the number of the mode and then restart. The set of commands is listed below:

• APRS Command and Control. In this mode, the CubeSatSim is waiting for an APRS packet containing the string MODE= followed by a letter of the new mode. The Green Power LED will blink with the number of the mode and then restart. The set of commands is listed below:

When Command and Control is turned on the first time, the default mode is Carrier (Squelch). To change it to DTMF or APRS mode, log into your Raspberry Pi and enter the command CubeSatSim/config -d

To troubleshoot Command and Control, you can look at the Command and Control log file on the Raspberry Pi Zero 2 by typing: CubeSatSim/log -c

The default Command and Control has no security built in. Anyone can transmit on the frequency and the CubeSatSim will respond.

You can add a small amount of security by activating PL (Private Line) codes on the FM receiver by logging into your Pi and typing CubeSatSim/config -P You will then need to program the same PL code into your FM transmitter.