Telemetrum ground station

The Telemetrum's Teledongle ground station is out of stock everywhere. We should make our own.

Success criteria

Receive signals from the Telemetrum flight computer over a distance of at least 10 kft.
Send data to a computer over USB virtual COM port in a format which can be interpreted in real time by the AltosUI flight monitoring software.

Make a PCB which contains a cheap microcontroller with USB support and the CC12xx or CC11xx radio transceiver.
- Make sure the PCB has mounting holes so it can fit into a case.
- Use an SMA connector.
Create software to copy the data from the receiver to the computer over USB through an intermediate MCU.

You must read this protocol specification for the AltusMetrum devices. Luckily, the Teledongle does minimal processing of the raw data, it only encodes it into an ASCII format before transmitting it over serial.
You should look at the schematics and PCB layout for the Teledongle for inspiration https://altusmetrum.org/TeleDongle/.
- I advise you don't use the NXP LPC11U14 since a cheaper microcontroller can do well
[!] PRO TIP: Use JLCPCB's part library to save on money! It tends to be cheaper per unit than buying from distributors online since JLC buys the parts at wholesale prices.
- You should consider using the basic parts library to place passives (resistors, capacitors). On Altium, all components in this library will have a JLC_PN attribute.
- Using extended parts outside the basic library list will incur a $3 USD fee per unique part, but when assembling 5 boards this still beats distributor prices. Of course, if a part is in the basic library it should be used if possible
- You may decide to use this alternative site to look up parts since JLC's parametric search isn't great https://yaqwsx.github.io/jlcparts/
- Try to place all/as many components on one side of the board only so you can use economic PCBA, which only places parts on one side.
- Feel free to ask me for Altium training, and I will probably need to talk about RF design considerations

Make this a module card which can go into a standalone battery powered ground station which does not need a laptop to use. This can be helpful if our laptops run out of energy and there are no generators.

Make a prototype setup to transmit and receive analog or digital video
Use a raspberry pi to overlay text containing telemetry such as altitude, position, etc.
Does not need to be a PCB yet

To be honest, I am not quite sure how this stuff works and I'm interested in learning as well
Two ways I can see this being done:
- 1. Use a project like wifibroadcast[1][2] which transmits digital video. Check out the link for more information.
- 1. Use a COTS analog 2.4 GHz video transmitter and receiver. Search 2.4 GHz video transmitter for examples. The TX6722 and RX6788 appears to be a common combination for 2.4 GHz band.
- Consider the differences in quality, error handling and bandwidth required when deciding between analog and digital video
I'll update this once we get past a prototype

Get position and altitude of the rocket through all stages of flight, including stages which exceed the velocity and/or altitude limitations of commercial GNSS receivers (510 m/s, 59,000 ft. See: Coordinating Committee for Multilateral Export Controls)

Make a prototype/MVP system for doing this. It doesn't need to fit into a rocket or require self-powering at this current design phase. I will update the project when we have an MVP working.
Test doing the post-processing on a single board computer.
Record enough data from launch to landing

Capture raw IQ data from an SDR and do the post-processing in something like GNSS SDR. Select an appropriate SDR which can digitize the L1 C/A GPS signal
This exists https://www.rtl-sdr.com/rtl-sdr-tutorial-gps-decoding-plotting/, but it seems to require a computer with windows installed to process the data.

Miniaturize this setup and add a power system for use on a rocket
Make a custom RF frontend specialized for the GNSS signals which is cheaper than buying an SDR
Is it possible to use an FPGA to process this signal in real-time? (It's apparently really hard to do... I searched and the latest real-time implementation is from 2013)