LTE on Raspberry Pi vs. Jetson
- Mihir Gupta
- R D
- Conall Kingshott
- Daniel Puratich
Overview
This document details the pros and cons of having the LTE module mounted on the Raspberry Pi (RPi) or the NVIDIA Jetson for the competition aircraft. The pros and cons are analyzed with a decision matrix a course of action will be determined. This document contains input from the follwing subteams
Autonomy
Mechanical
Electrical
Embedded Flight Software
The data to be transmitted through LTE:
Telemetry (MAVLink)
Video
This topic has been discussed with stakeholders at the end of 2023-09-19 AEAC 2024 Sync and the conversation was led by @Mihir Gupta .
Decision Matrix
 | Separated (LTE on RPi) | Combined (LTE on Jetson) |
|---|---|---|
Description | Both the RPi and the Jetson will be on the competition drone. The LTE module will be mounted on the RPi and will be responsible for telemetry. The Jetson will be responsible for running the Autonomy airside system. | The LTE module will be mounted on the Jetson and the RPi will not be on the competition drone. The Jetson will be responsible for telemetry and running the Autonomy airside system. |
Pros and cons | Autonomy: By separating the LTE module from the Jetson, we don’t have to worry about integration between LTE and autonomy airside system on the Jetson. Mechanical: The RPi and a case assembly will be around 100g. Lots of effort has been put into making this drone as light as possible. Mechanical: This takes up extra space on the surface of the drone which is important for mounting various electronics and payload systems. Autonomy: Additional physical communication required between RPi and flight controller. Requires flight controller to support multiple inputs and outputs. Autonomy: Possible conflicting requested MAVLink message frequency from Autonomy Airside and ground station. | Mechanical: Saved weight on the frame. Mechanical: Reduction of surface area taken up by our communications on the frame. Electrical: Jetson is already there, and we won’t have to use RPi. Simplifying harnessing. Autonomy: MAVLink communication centralized. Autonomy: Forced to disable debugging on Jetson UART 0 making it very problematic if we need to reflash the Jetson OS. Autonomy: Possibility for performance issues to occur if both systems are running on the Jetson. Autonomy: Difficult to mount LTE module on the Jetson as the carrier board is already mounted on the Jetson. Additional software required to support simultaneous Autonomy Airside and LTE communication. Telemetry need to send data first to Jetson, then forward to ground station. |
Estimated cost | MEDIUM Would need extra support from Mech and EE to run both systems separately. | large Lots of support will be needed from the software side to run both systems on the Jetson. Furthermore, lots of testing and validation will be needed to ensure both systems run without issues. |
Plan of Action
As of the information provided to us in the 2023-09-19 AEAC 2024 Sync meeting, the plan is to have both systems run separately for now, and if there is time we can try to combined approach and add LTE to the Jetson. The rationale behind this decision is to have a viable product ready for competition first and then iterate on optimizing the systems if we have the time.
As of the information provided to us in the 2023-09-24 Conops Brief #1 meeting, Mech called out the issue of the drone being overweight. Moreover, the Autonomy team discovered that it is possible to run their airside system on the groundside. The Autonomy team plans to work on the airside system on the Jetson and porting the airside system to run on the groundside. If the drone is not overweight the Autonomy team will run the airside system for auto-landing on the Jetson. If the drone is overweight we will send the information needed from the drone to the groundside with the LTE system and run the airside system pipeline on the ground.