Radio Module - Rowan-Rocketry/SRAD-Avionics GitHub Wiki

Cyber-Physical System Description

1. Sensing

The onboard radio module will constantly receive GPS signals. It will also receive rocket state, pressure, and acceleration from the recovery module. It may receive additional data from the other modules, but this is currently being researched/discussed.

2. Computing

The onboard radio module uses GPS timestamps to calculate GPS coordinates of rocket. It will convert GPS data and state, accelerometer, and pressure data to an APRS packet.

3. Actuating

4. Communicating

The radio module currently will be using APRS (Automatic Packet Reporting System) protocol to transmit data from the rocket to ground. Communication using APRS will likely occur on 440 MHz band, but this is in discussion. APRS requires an Amateur Radio License, but is open-standard (no paywall). The TeleMetrum, a COTS flight computer (and the team's current planned backup), has an existing wire diagram for using APRS. and An alternative to APRS is LoRa (Long Range) protocol which is transmitted in the 800-900 MHz frequencies, and LoRa does not require a license. Disadvantages are being closed-standard (standards behind a paywall) and current lack of wire diagrams for using LoRa.

Currently, the radio module (and subsequently each flight computer module) will be using UART (Universal Asynchronous Receiver Transmitter) to communicate. Use of CAN (Controller Area Network) was originally considered, but UART was selected due to CAN's more complicated programming to avoid bus collisions. UART devices are directly wired to every other device, resulting in many wires, so the team is currently planning on having only two devices communicating with one another to avoid relatively complex wiring.

Hardware Overview

1. Microcontroller

Part Number: STM32H503RBT6
Planned Vendor: STMicroelectronics
Manufacturer: STMicroelectronics

2. Radio Transceiver

Part Number: CC1200
Planned Vendor: DigiKey
Manufacturer: Texas Instruments

3. GPS Antenna

Part Number: APAE 1590R2540AKDB1-T
Planned Vendor: DigiKey
Manufacturer: Abracon LLC

4. Front End Saw Filter

Part Number: B39162B8813P810
Planned Vendor: DigiKey
Manufacturer: Qualcomm

5. GPS Transceiver

Part Number: MAX-8C-UBLOX
Planned Vendor: DigiKey
Manufacturer: U Blox

6. Flash Memory

Flash 128 MBIT
Part Number: W25Q128JVS
Planned Vendor: DigiKey
Manufacturer: Winbond Electronics

7. USB-C/Power

Part Number: USB4105-GF-A
Planned Vendor:
Manufacturer:

8. PCB

Purchasing from JLCPCB