LoRa Cloud

The LoRa Cloud integration provides an integration with the LoRa Cloud Modem & Geolocation Services. This service can be used for handling LoRa Edge™ LR1110 and LoRa Basics™ Modem-E devices and / or different forms of geolocation:

• TDOA (Time Difference Of Arrival)
• RSSI (signal strength)
• Wifi (Wifi access-point bssid scanning)
• GNSS (using the LR1110)

LoRa Edge™ LR1110 and LoRa Basics™ Modem-E devices

If this option is enabled, you must configure the GNSS port (default 198) and Modem port (default 199). If ChirpStack receives an uplink on these ports, then it will forward the uplink as the respective message type to LoRa Cloud.

If your device adheres to the LoRa Edge™ Tracker Reference Design protocol, then you can enable this option as well. In this case ChirpStack will know how to parse the protocol payloads to retrieve the geolocation payload from it, after which it will try to resolve it using the LoRa Cloud geolocation resolver.

Advanced options

For other devices, you can configure geolocation using the advanced options.

TDOA

For TDOA based geolocation, at least three gateways are required that implement fine-timestamping. Please refer to the ChirpStack Geolocation page for more information about the fine-timestamp.

Wifi

When using Wifi based geolocation, you must configure a payload decoder for decoding the FRMPayload into an object expected by the LoRa Cloud integration.

Example payload decoder:

// bytes contains one or multiple times thw following encoding:
// [MAC Address: 6 bytes] | [Signal strength (int8): 1 byte]
function Decode(fPort, bytes, variables) {
  var i = 0;
  var len = bytes.length;
  var out = {access_points: []};
  
  for (; i < len ;) {
    out.access_points.push({macAddress: bytes.slice(i, i + 6), signalStrength: int8(bytes[i+6])});
    i += 7;
  }
  return out;
}

// convert a byte value to signed int8
function int8(byte) {
  var sign = byte & (1 << 7);
  if (sign) {
    return 0xFFFFFF00 | byte;
  }
  return byte;
}

The an example of the output produced by the above codec: 2

{
	"access_points": [
		{
			"macAddress": "...", // base64 encoded
			"signalStrength": -70
		},
		{
			"macAddress": "...", // base64 encoded
			"signalStrength": -80
		},
		{
			"macAddress": "...", // base64 encoded
			"signalStrength": -75
		}
	]
}

In this case you must configure the Wifi payload field in the LoRa Cloud Geolocation configuration to access_points.

GNSS

When using GNSS based geolocation, you must configure a payload decoder to split the GNSS payload part from the uplink FRMPayload. For example, your application might not only send the GNSS payload, but also sends the number of satellites.

Example payload decoder:

// bytes has the following encoding:
// [Sat. count (uint8): 1 byte] | [LR1110 GNSS payload: remaining bytes ]
function Decode(fPort, bytes, variables) {
  return {
    "sat_count": bytes[0],
    "lr1110_gnss": bytes.slice(2, bytes.length)
  };
}

In the above case, you must configure the GNSS payload field in the LoRa Cloud Geolocation configuration to lr1110_gnss.

When using the GNSS resolver, either the timestamp included the GNSS payload or the receive timestamp (of the uplink) can be used.