:satellite: Satellite communication demo for RFThings RF210
An Arduino sketch example shows how to communicate with a terrestrial gateway and LacunaSpace satellites.
ABP activation mode is used for both terrestrial and space communication. For testing simplicity, two different sets of credentials (dev address and keys) are used for terrestrial and space communication respectively.
Board Manager
The example used stm32duino/Arduino_Core_STM32. Refer to this Getting Started for installation guide of this core.
To compile the example, select board manager as followings in ArduinoIDE
Libraries
The sketch required following libraries. Make sure you have them installed:
| Header Included | Library Reposistory |
|---|---|
| RFThings.h | https://github.com/nguyenmanhthao996tn/LoRaSpaceLib-STM32WL |
| STM32LowPower.h | https://github.com/stm32duino/STM32LowPower |
| STM32RTC.h | https://github.com/stm32duino/STM32RTC |
| Sgp4.h | https://github.com/Hopperpop/Sgp4-Library |
| MicroNMEA.h | https://github.com/stevemarple/MicroNMEA |
Two Line Element Set (TLE)
TLE data in tle.h file has to be updated with recent TLE from the targeted satellite to avoid pass predicting error.
TLE data & other information could be find by contacting Satellite provider or the following table:
| Satellite | Norad ID | TLE & Satellite info |
|---|---|---|
| LS2B | 47948 | https://www.n2yo.com/satellite/?s=47948 |
| LS2E | 48924 | https://www.n2yo.com/satellite/?s=48924 |
| ... | ... | (More satellite is coming) |
Configuration files
LoRaWAN credentials are defined in project_config.h for terrestrial and space terminals. These values need to be updated with your own application / network server.
For terrestrial communication:
In project_config.h |
Abbreviation | Description |
|---|---|---|
nwkS_key_terrestrial[] |
DevAddr | Device address |
appS_key_terrestrial[] |
AppSKey | Application Session Key |
dev_addr_terrestrial[] |
NwkSKey | Network Session Key |
For space communication:
In project_config.h |
Abbreviation | Description |
|---|---|---|
nwkS_key_space[] |
DevAddr | Device address |
appS_key_space[] |
AppSKey | Application Session Key |
dev_addr_space[] |
NwkSKey | Network Session Key |
For other configurations, refer to project_config_h.md.
Cautions for actual deployment
For actual deployment of the terminal/device, following debugging configurations SHOULD be disabled to reduced power consumption.
- SERIAL_LOG_ENABLE
- SERIAL_LOG_DEBUG_ENABLE
- SYSTEM_SLEEP_DEBUG
This example is design for The RAK3172 module integrated on RFThings RF210 to work independently. The integrated ESP32-C3 should be also put into sleep mode to maximize the device's battery lifetime.
Payload format
The uplink payload format remains the same for terrestrial and space communication. Payload's length should be always 27 bytes. An example of packet decoder in Javascript can be find in docs/packet_formatter_ttn.js
| Payload | Description | Value |
|---|---|---|
| payload[0] | Is this packet sent to satellite? | 1: Send to satellite 0: Send to terrestrial gateway |
| payload[4:1] | Packet build epoch | N/A |
| payload[8:5] | Device last latitude | N/A |
| payload[12:9] | Device last longtitude | N/A |
| payload[16:13] | Next satellite pass start epoch | N/A |
| payload[20:17] | Next satellite pass duration in second(s) | N/A |
| payload[24:21] | Next GPS update epoch | N/A |
| payload[26:25] | Battery voltage ADC | N/A |
FAQ
Q1: I can compile but cannot upload. What happened?
If you get the error as the following image, make sure your RF210 board has Bootloader mode activated and hit the upload again. To trigger the Bootloader mode, hold the B_RAK button and press R_RAK button.
Q2: How can I get the AT Command firmware back?
In order to get the space communicating modulation (LR-FHSS), this demo sketch is using a different firmware/core which is from Arduino_Core_STM32. To get the AT Command firmware back, you need the firmware from RAKwireless. Follow the instruction here: XuanMinh201/RF210
At RFThings, we are developing firmware merging these two feature. It's coming soon ...
Q3: How about power consumption?
With the LoRaSpaceLib-STM32WL version 1.0.1, I can reached ~284uA (580nW) when the terminal is inactive.
The below image is the power consumption of first 15 seconds after startup.
For detailed power consumption in different stages of the firmware, I left my OTII project file in the docs/q3_power_consumption.otii folder.
Credits
Communication with :satellite: satellites :satellite: from small terminal/device is challenging but not too hard. Stick with us at RFThings Support eMail in this adventure and we can make it there.
🍀 GLHF! 🍀