Xsens MTi-G Primary Flight Display

Full-featured PFD (Primary Flight Display) driven by an Xsens MTi-G IMU/GPS over serial, built with PyQt6.

Fullscreen with debug panels and GPS satellite view

Windowed mode

Features

PFD Instruments

• Attitude indicator — selectable source: raw accelerometer (drift-free) or EKF (fused IMU/GPS). Pitch ladder with 2.5° fine marks
• Synthetic vision (SVS) — database-driven 3D terrain view using AWS Terrain Tiles. TAWS-style altitude-relative coloring (red/amber/yellow/green), directional sun shading, distance haze, grid overlay. Togglable via SYN VIS softkey
• Bank arc — slip/skid indicator, auto-calibrated during AHRS alignment
• Speed tape — GPS ground speed with GS readout box, rolling drum digits, LP filtering, noise squelch, V-speed color bands (white/green/yellow arcs, red Vne line, barber-pole overspeed)
• Altitude tape — selectable source: barometric (QNH corrected) or GNSS. Rolling drum digits, label strip indicates source
• Compass rose — rotating 360° HSI with upright labels, aircraft symbol, heading bug with notch marker. Compass course correction offset
• Vertical speed indicator — selectable source: GNSS (GPS vertical velocity) or barometric (pressure-derived with two-stage LP filter). Non-linear scale with value readout
• Flight path vector (FPV / velocity vector)
• Heading bug — adjustable with +/- keys, cyan display with HDG readout
• GNSS status — fix status overlay (3D FIX / 2D FIX / SEARCHING / NO FIX) with color coding
• Fail flags — red X overlay when data is unavailable (ATT, SPD, ALT, V/S, HDG)
• AHRS alignment — startup initialization with progress bar, auto-zero attitude and slip/skid

Moving Map

• Split view — 50/50 horizontal split with PFD on the left, map on the right
• Tile providers — OpenStreetMap, OpenTopoMap, OpenAIP (aviation overlay with airspaces, airports, navaids)
• Map controls — drag to pan, scroll to zoom, north-up / heading-up toggle, center-on-aircraft button
• Heading-up mode — smooth map rotation following compass heading when centered
• Aircraft symbol — white airplane silhouette with black outline at GPS position
• Tile caching — disk and memory cache with cache management in settings
• Connection test — verify tile provider connectivity from settings

Variometer Audio

• Glider-style vario sound — beeping tone in climb (500–1500 Hz, 1.7–6.7 beeps/sec), continuous low tone in sink (200–500 Hz), configurable dead band
• Adjustable volume, enable/disable via softkey bar or settings dialog

Softkey Bar

• Softkey bar — 12 fixed button positions at the bottom of the PFD
• Touch-friendly buttons: UNIT, QNH, VARIO, AHRS, MAP, HDG UP, ZOOM +/-, CTR MAP, SYN VIS, MENU
• Activity indicators (green bar) for toggle states (vario, map, synvis)
• Frameless popup dialogs for QNH adjustment and AHRS functions
• Context-sensitive buttons appear when map is active

Data & Configuration

• Data panels — raw sensor readouts (accelerometer, gyroscope, magnetometer, GPS, pressure, satellite C/N0 bar graph, G-force), quick-access buttons, toggle with D key
• Settings dialog — tabbed configuration: Device, Output, Filter, GPS/Mag, Display, Map, Commands
  • Attitude/altitude/VSI source selection
  • Compass course correction offset
  • QNH with set-from-sensor, units, V-speed bands, vario audio
  • Map provider, OpenAIP overlay + API key, tile cache management
  • Synthetic vision enable/range, terrain test injection
  • Filter scenario, gravity magnitude, processing flags, sensor/object alignment
  • GPS lever arm, magnetic declination, in-run compass calibration
  • Baudrate, sample rate, transmit delay, sync-out, error mode, location ID
• Persistent settings — all user preferences saved to config.json and restored on next launch (including map state, zoom level, vario, synvis)
• Unit toggle — metric (km/h, meters, m/s) or imperial (knots, feet, ft/min), V-speed bands convert dynamically

Communicates using the Xsens Mark III legacy protocol (MTData 0x32).

Requirements

• Python 3.10+
• Xsens MTi-G connected via USB-serial

Install

python -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt

Usage

python main.py [--port /dev/tty.usbserial-XSU5ZPZX] [--baud 230400] [--windowed]

Argument	Default	Description
--port	/dev/tty.usbserial-XSU5ZPZX	Serial port
--baud	230400	Baud rate
--windowed	off (fullscreen)	Start in windowed mode

QNH pressure, units, V-speeds, heading bug, and other settings are persisted in config.json.

Keyboard Shortcuts

Key	Action
Z	Level AHRS (set current attitude as zero)
R	Reset level bias
C	Calibrate (orientation reset, keep stationary)
U	Toggle units (US / Metric)
D	Toggle debug data panels
H	Sync heading bug to current heading
+/-	Adjust heading bug by 1°
M	Settings menu
F	Toggle fullscreen
Q/Esc	Quit

Architecture

File	Purpose
main.py	Application entry point, softkey bar, popup dialogs
sensors.py	Xsens MTi-G protocol, serial I/O, data parsing
pfd_widget.py	PFD rendering (attitude, tapes, HSI, synthetic vision)
map_widget.py	Slippy map with tile providers and aircraft overlay
terrain.py	Terrain elevation provider (AWS Terrain Tiles)
vario_audio.py	Variometer audio synthesiser (glider-style beeping)
data_panels.py	Debug data panel strip (sensors, GNSS, satellites)
settings_dialog.py	Tabbed device and display configuration UI
config.py	JSON settings persistence
diag.py	Standalone sensor diagnostic (drift/bias statistics)
test_calibrate.py	Calibration validation harness

License

This project is dual-licensed:

• Open source — GNU AGPL-3.0. You may use, modify, and distribute this software freely under AGPL terms. Any networked or distributed derivative work must also be released under AGPL-3.0 with full source code.
• Commercial — If you want to use this software in a proprietary/closed-source product without AGPL obligations, contact the author for a commercial license.

Author

Bjoern Heller tec@sixtopia.net