Septentrio GPS

What it does:

• Reads NMEA messages from the gps receiver (over serial or ip)
• parses them and calculates ENU coordinates
• publishes latlon and enu data as json to mqtt topics.

mqtt messages

topic: /gps/position
{"lat":51.45655803,"lon":6.08187908,"x":-13.354,"y":-67.59,"gps_qual":4,"time":"14:27:27.800000","ts":1726149158.437}

topic: /gps/direction
{"heading":152.22,"heading_stdev":0.084,"theta":-1.0859,"ts":1726149158.441}

1. Configure receiver

Install and configure gps receiver as described in installation manual

2. Launch docker container

get docker image (use tag for version)

registry.gitlab.com/roxautomation/components/septentrio-gps:latest

launch container with

docker run \
-e GPS_NODE_TYPE=ip \
-e GPS_IP_HOST=<hostname> \
registry.gitlab.com/roxautomation/components/septentrio-gps:latest

Set these environment variables to override default settings:

MQTT

• MQTT_HOST: MQTT server host (default: "localhost").
• MQTT_PORT: MQTT server port (default: 1883).
• MQTT_POSITION_TOPIC: MQTT topic for GPS positions (default: "/gps/position").
• MQTT_DIRECTION_TOPIC: MQTT topic for GPS directions (default: "/gps/direction").

GPS

• GPS_NODE_TYPE: "serial" or "ip" (default: "serial").
• GPS_SERIAL_PORT: Serial port for GPS (default: "/dev/gps_nmea").
• GPS_SERIAL_BAUD: Baud rate for GPS serial communication (default: 115200).
• GPS_IP_HOST : ip server address (default localhost)
• GPS_IP_PORT : ip port (default 28000)
• GPS_REF: gps reference point, provide lat,lon, example: GPS_REF="51.123,6.456"

Precision

• DIGITS_POSITION : meter position accuracy, defaults to 3
• DIGITS_LATLON : digits latitude and longitude, defaults to 8
• DIGITS_ANGLE : angle accuracy, defaults to 4

(note: configuration is defined in config.py)

Development

There should be mqtt broker available on the host system. If not, there is a docker image for that:

docker run -d --name mosquitto --restart unless-stopped -p 1883:1883 registry.gitlab.com/roxautomation/images/mosquitto:latest

• Open in VSCode devcontainer. Virtual com port is located at /tty/tty_nmea_rx
• Pre-recorded nmea stream can be sent to com port with replay_data.py in integration/data folder.