Having trouble with a decoder for a browan industrial tracker, the payload decodes the gnss fine in node, but doesnt seem to decode them at all in chirpstack. is there a function or inbuilt being called thats not supported by the quickjs? appreciate any help.
//hex to binary function
function hex2bin(hex) {
return (parseInt(hex, 16).toString(2)).padStart(8, '0');
}
// little-endian format
function littleendian(inputpayload) {
let data = inputpayload.match(/../g);
let buf = new ArrayBuffer(4);
// Create a data view of it
let view = new DataView(buf);
// set bytes
data.forEach(function (b, i) {view.setUint8(i, parseInt(b, 16));});
// get an int32 with little endian
let num = view.getInt32(0, 1);
return num;
}
// GPS Lat calculate
function gnss_LatCal(firstbit, intput_lat) {
if (firstbit==0) {
let Lat_littleend_int = littleendian(intput_lat);
//const Lat_bit_01 = (Lat_littleend_int| (0xF0000000)) ^ (0xF0000000);
let Lat_bit_01 = (Lat_littleend_int| (0xF0000000)) ^ (0xF0000000);
//const Lat_bit_02 = Lat_bit_01/1000000;
let Lat_bit_02 = Lat_bit_01/1000000;
return (Lat_bit_02.toString());
} else {
let Lat_littleend_int = littleendian(intput_lat);
let Lat_bit_01 = Lat_littleend_int^0xFFFFFFFF;
//const Lat_bit_02 = (Lat_bit_01| (0xF0000000)) ^ (0xF0000000);
let Lat_bit_02 = (Lat_bit_01| (0xF0000000)) ^ (0xF0000000);
//const Lat_bit_03 = Lat_bit_02/1000000;
let Lat_bit_03 = Lat_bit_02/1000000;
return -(Lat_bit_03.toString());
}
}
// GPS Lat calculate
function gnss_LongCal(firstbit, intput_long){
if (firstbit==0) {
let Long_littleend_int = littleendian(intput_long);
//const Long_bit_01 = (Long_littleend_int| (0xE0000000)) ^ (0xE0000000);
let Long_bit_01 = (Long_littleend_int| (0xE0000000)) ^ (0xE0000000);
//const Long_bit_02 = Long_bit_01/1000000;
let Long_bit_02 = Long_bit_01/1000000;
return (Long_bit_02.toString());
} else {
let Lat_littleend_int = littleendian(intput_long);
let Long_bit_01 = Lat_littleend_int^0xFFFFFFFF;
//const Long_bit_02 = (Long_bit_01| (0xE0000000)) ^ (0xE0000000);
let Long_bit_02 = (Long_bit_01| (0xE0000000)) ^ (0xE0000000);
//const Long_bit_03 = Long_bit_02/1000000;
let Long_bit_03 = Long_bit_02/1000000;
return -(Long_bit_03.toString());
}
}
// GNSS position estimate calculate
function gnss_PositCal(intput_posit){
let Posit_int_01 = parseInt(intput_posit,16);
//const Posit_bit_01 = (Posit_int_01>>5);
let Posit_bit_01 = (Posit_int_01>>5);
//const Posit_bit_02 = Math.pow(2,(Posit_bit_01+2));
let Posit_bit_02 = Math.pow(2,(Posit_bit_01+2));
return (Posit_bit_02.toString());
}
//decoder function
function decodeUplink(input) {
let b = input.bytes;
let port = input.fPort;
let decoded = {};
// create the object to collect the data for returning the decoded payload
if (port == 136) { // Industrial Tracker Sensor
let indust_hex = b.toString("hex").substring(0, 2); // Sensors status HEX
let indust_binary = hex2bin(indust_hex);
let moving_st = indust_binary.substring(7, 8); // moving mode
let nognss_st = indust_binary.substring(4, 5); // no GNSS fix status
let gnsserror_st = indust_binary.substring(3, 4); // GNSS error
let battry_hex = b.toString("hex").substring(2, 4); // battery calculate
let battry_int = parseInt(battry_hex, 16);
let battry_volt = (25+battry_int)/10;
let temperature_hex = b.toString("hex").substring(4, 6); //temperature calculate
let temperature_int = parseInt(temperature_hex, 16);
let temperature_final = temperature_int -32;
/* Latitude as last reported by GNSS receiver - calculate */
let gnssLat_hex = b.toString("hex").substring(6, 14);
let gnssLatbit_hex = b.toString("hex").substring(12, 14); // Latitude Negative sign bit
let gnssLatbit_neg = (hex2bin(gnssLatbit_hex)).toString().substring(4,5);
let gnssLat_final = gnss_LatCal(gnssLatbit_neg,gnssLat_hex);
/* Longitude as last reported by GNSS receiver - calculate */
let gnssLong_hex = b.toString("hex").substring(14, 22);
let gnssLongbit_hex = b.toString("hex").substring(20, 22); // Latitude Negative sign bit
let gnssLongbit_neg = (hex2bin(gnssLongbit_hex)).toString().substring(3,4);
let gnssLong_final = gnss_LongCal(gnssLongbit_neg,gnssLong_hex);
/* position accuracy estimate - calculate */
let gnssPosit_hex = b.toString("hex").substring(20, 22);
let gnssPosit_final = gnss_PositCal(gnssPosit_hex);
decoded.moving = parseInt(moving_st); // 1 - moving mode, 0 - stationary mode
decoded.gnss_fix = parseInt(nognss_st); // 1 - no GNSS fix, 0 - GNSS fixed
decoded.gnss_error = parseInt(gnsserror_st); // 1 - GNSS error, 0 - GNSS OK
decoded.batt_volt = parseFloat(battry_volt);
decoded.temperature = parseFloat(temperature_final);
decoded.latitude = parseFloat(gnssLat_final);
decoded.longitude = parseFloat(gnssLong_final);
decoded.pos_est = parseInt(gnssPosit_final);
}
return {data: decoded}
}
pl = "AAwykBYlDjIv/wg=";
buff = Buffer.from(pl, 'base64');
console.log(buff);
//Test function output
console.log(decodeUplink({bytes: buff, fPort: 136}));
output in node (expected in chirp)
<Buffer 00 0c 32 90 16 25 0e 32 2f ff 08>
{
data: {
moving: 0,
gnss_fix: 0,
gnss_error: 0,
batt_volt: 3.7,
temperature: 18,
latitude: -31.123823,
longitude: 150.94149,
pos_est: 4
}
}
actual decoded in chirpstack.
