locapack

Brief

Another localisation packet protocol to send/receive localisation data over networks.

Details

LocaPack is an implementation of the locapack protocol used to send or receive various localisation data over wired and wireless networks.

LocaPack enables the transport of:

• universal GNSS localisation coordonates such as latitude/longitude data,
• locally referenced localisations, such as {x,y} positions in an indoor environment,
• inter-node proximity information such as ranging data.

Some extra features are also avalable, such as:

• automatic mapping/translation of coordonates between universal GNSS/locally referenced localisations,
• movement_id, that enables extra movement information based on another sensor (typically a local accelerometer),
• packet sequence numbering and local timestamping, to track positions and detect missing information,
• message hashing, to send shorter but incomplete payloads, to respect privacy.

Several implementations are available:

• Embedded: C++ class (Arduino library)
• Infrastrucure/IoT: Node-RED palette
• Portable: python

A Json description of the messages is also available.

Implementation

LocaPack is available as a Node-RED Palette, ie a collection of nodes to produce or decode locapack messages.

Node-RED implementation status:

• encode/decode header,
• encode/decode universal GNSS packets,
• encode/decode locally referenced packets.

JSON messages

LocaPack messages are also available in JSON.

Example of a Universal GNSS localisation packet:

{
  "header": {
    "protocol_version": 1,
    "device_id_size": 2,
    "packet_type": 1,
    "movement_id_presence_flag": false,
    "timestamp_presence_flag": true
  },
  "sequence_number": 2746,
  "timestamp": 27850001,
  "device_id": 237,
  "payload": [192,49,131,47,66,150,8,165,63,154,153,18,67,164,112,157,63],
  "universalGnssPacket": {
    "header": {
      "altitude_presence_flag": true,
      "dop_presence_flag": true
    },
    "latitude": 43.9,
    "longitude": 1.1,
    "altitude": 146.6,
    "dop": 1.2300000190734863
  }
}

Example of a Locally Referenced localisation packet:

{
  "LocaPack": {
    "header": {
      "protocol_version": 1,
      "device_id_size": 2,
      "packet_type": 2,
      "movement_id_presence_flag": false,
      "timestamp_presence_flag": true
    },
    "sequence_number": 163,
    "timestamp": 1630289,
    "device_id": 124,
    "payload": [224,0,0,128,63,0,0,0,64,0,0,64,64,0,0,128,64,136,119,102,85,68,51,34,17],
    "locallyReferencedPacket": {
      "header": {
        "z_presence_flag": true,
        "dop_presence_flag": true,
        "frameofref_id_presence_flag": true
      },
      "x": 1,
      "y": 2,
      "z": 3,
      "dop": 4,
      "frameofref_id": 9833440827789222000
    }
  }
}

License

Locapack is distributed under the GPLv3 license.