fixposition

Python driver for fixposition gps

NOTE: work-in-progress

Currently these messages are supported: GGA,HDT,ODOMETRY

Functionality overview

• parser.parse(msg: str, ignore: List[str] = []) -> FPX_Message | None: - parse NMEA message to a NamedTuple
• record and replay messages with fixposition cli
• use gps_node.FpxNode class as async node to interface with fixposition device over socket.

Usage

Message parsing:

from fixposition import parser

msg = "$GPHDT,61.7,T*05\r\n"

data = parser.parse(msg)

CLI tool

This package provides a command-line tool fixposition:

Usage: fixposition [OPTIONS] COMMAND [ARGS]...

Options:
--version  Show the version and exit.
--help     Show this message and exit.

Commands:
listen  Listen to messages and print them to stdout
node    Start the gps node
record  Record messages to file
replay  Replay messages from a file or default data if not provided.

How it works

• message definitions are in fixposition.messages. Each submodule contains a parse() function.
• @validate_checksum decorator adds nmea checksum to parse function.
• parser.parse(msg) returns NamedTuple of a message

See .messages code, extending this should be easy.

References

• FP_A messages
• FP_A-ODOMETRY
• HDT
• GGA

Development

• develop and test in devcontainer (VSCode)
• devops are managed with invoke , see tasks.py

Tooling

• Verisoning : bump2version
• Linting : pylint
• Formatting: black
• Typechecking: mypy
• scripting: invoke : see tasks.py

What goes where

• src/fixposition app code. pip install . .
• tasks.py automates common tasks with invoke