This example demonstrates how an UCA-AIOT board can send data to the LS2B satellite from Lacuna Space. The device will send data to Lacuna Space LS2B satellite when it passes. The data could be retrieved later from The Things Network Console. It's also send a periodic status packets to terrestrial LoRaWAN Gateway.
FYI: This source code is aim to test the connectivity between DKAIoT board with Lacuna Space satellites only. It uses a TLE which is not updated while the board runs. Therefore, the prediction of satellite passes will have bigger & bigger error over the time. For practical deploying purpose/scenario, please contact Lacuna Space for official firmware or implement the auto TLE update.
This demonstration uses The Things Network v3 (TTN) to receive data from UCA-DKAIOT board. It's recommended to use 2 different ABP devices on TTN to monitor data from Satellite and from terrestrial LoRaWAN Gateway. Refer to section Manually registering a device in this instruction from TTN to create your own application and devices.
Important: For device that will receive data from satellite, if you are NOT using EU868 Frequency Plan, add following Factory Preset Frequencies for downlink from Satellite in General Settings > Network layer > Advanced MAC Settings:
| Factory Preset Frequencies |
|---|
| 868100000 |
| 868300000 |
| 868500000 |
| 867100000 |
| 867300000 |
| 867500000 |
| 867700000 |
| 867900000 |
-
Step 2.1: Device Address, NwkSKey & AppSKey
In the Arduino source code, add the Device Address, NwkSKey & AppSKey information that retrieved from The Things Network in Step 1 to the source code.
- Step 2.2: TLE for Lacuna Space LS2B
For satellite tracking / predicting pass capability, it requires Two Line Element (TLE) of that satellite. Please update the latest TLE in source code from https://www.n2yo.com/satellite/?s=47948 or Space-Track.org for more accurate pass prediction.
- Step 2.3 (OPTIONAL): Other parameters
There are other parameters in #define format the source code can help optimizing the performance in different use cases. Refer to the following Project Configuration / Parameter Description section for more information.
In order to check/list your packets from Lacuna Satellite in cased that The Things Network failed/drop it, Device Address and NwkSKey of the Satellite device must be declared to Lacuna Dashboard. Go to Lacuna Dashboard, click Add new device and fill in your device information (retrieved in Step 1).
If you don't have an Lacuna Dashboard account or need support, please check out Lacuna Forum.
// #define DEBUG_SLEEP
Uncomment DEBUG_SLEEP define will replace sleep functions of the UCA-DKAIOT board with delay. This allow Serial via USB work properly.
Make sure to comment/delete this option and select USB Type as No USB (low-power) for field deployment. When debugging with Serial, do it the opposit way.
#define SAT_PACKET_PERIOD_S (15) // 15 seconds
SAT_PACKET_PERIOD_S is the time (in seconds) between packets send to satellite when it's available (pass).
#define MIN_PASS_ELAVATION (25) // 25 degrees
MIN_PASS_ELAVATION is the minimum pass elavation (in degree) that the UCA-DKAIOT board will wake up and transmit packets.
#define TERRESTRIAL_STATUS_PACKET_PERIOD_S (15 * 60) // 15 minutes
TERRESTRIAL_STATUS_PACKET_PERIOD_S is the time (in seconds) between status packets send to terrestrial LoRaWAN gateway.
#define GNSS_UPDATE_PERIOD_S (24 * 60 * 60) // 24 hours
GNSS_UPDATE_PERIOD_S is the time (in seconds) between two GNSS update for time and coordinates. This is relative time. GNSS update time could be change if it too close to a satellite pass.
#define GNSS_RESCHEDULE_OFFSET_S (30 * 60) // 30 minutes
GNSS_RESCHEDULE_OFFSET_S is the minumum time (in seconds) between a GNSS Update and a satellite pass. GNSS Update Time will be changed to Satellite Pass Stop + GNSS_RESCHEDULE_OFFSET_S if it violates the offset.
Packets for both terrestrial LoRaWAN transmission and Satellite transmission are in 25-byte format as following:
The following Custom Javascript Payload Formatter can be applied on The Things Network console for decoding packets.
function decodeUplink(input) {
var packet_type = (input.bytes[0] === 1) ? 'satellite' : 'terrestrial';
var send_epoch = (input.bytes[1] << 0) | (input.bytes[2] << 8) | (input.bytes[3] << 16) | (input.bytes[4] << 24);
var bat_voltage_adc = (input.bytes[5] << 0) | (input.bytes[6] << 8);
var battery_vol = bat_voltage_adc * 4.5 / 4095.0;
var tle_age = (input.bytes[7] << 0) | (input.bytes[8] << 8) | (input.bytes[9] << 16);
var next_pass_epoch = (input.bytes[10] << 0) | (input.bytes[11] << 8) | (input.bytes[12] << 16);
next_pass_epoch += send_epoch;
var next_gnss_update_epoch = (input.bytes[13] << 0) | (input.bytes[14] << 8);
next_gnss_update_epoch += send_epoch;
var last_gnss_fix_time = (input.bytes[15] << 0) | (input.bytes[16] << 8);
var gnss_latitude = (input.bytes[17] << 0) | (input.bytes[18] << 8) | (input.bytes[19] << 16) | (input.bytes[20] << 24);
gnss_latitude /= 1e7;
var gnss_longitude = (input.bytes[21] << 0) | (input.bytes[22] << 8) | (input.bytes[23] << 16) | (input.bytes[24] << 24);
gnss_longitude /= 1e7;
if (input.bytes.length == 25) {
return {
data: {
packet_type: packet_type,
send_epoch: send_epoch,
battery_vol: battery_vol,
tle_age: tle_age,
next_pass_epoch: next_pass_epoch,
next_gnss_update_epoch: next_gnss_update_epoch,
last_gnss_fix_time: last_gnss_fix_time,
gnss_latitude: gnss_latitude,
gnss_longitude: gnss_longitude,
raw_data: input.bytes
},
warnings: [],
errors: []
};
}
else {
return {
data: {
raw_data: input.bytes
},
warnings: ["Unrecognized payload"],
errors: []
};
}
}
This demonstration uses Hopperpop/Sgp4-Library for predicting the next pass of the satellite. Consider to give him star if you can.
Goodluck with your space investigation!