SITL Forge – External FC: iNAV

This DLC adds a software-in-the-loop bridge between SITL Forge - FPV Laboratory and iNAV firmware running on your PC. The built-in PID controller is replaced with the real firmware, so you fly, navigate, and tune against the same code that runs on real hardware — driven by the simulator's 1000Hz physics model, calibrated against real bench measurements.

Requires the base app: SITL Forge - FPV Laboratory.

---What This DLC Adds

MSP-based HITL bridge — the firmware drives the simulator through iNAV's standard MSP_SIMULATOR protocol

Per-motor outputs polled from the firmware, smoothed into the 1000Hz physics step

50Hz RC channel link — joystick or RC transmitter feeds the firmware's stick inputs

Simulated GPS and compass — unlocks iNAV's navigation modes: position hold, altitude hold, return-to-home, waypoint missions, and auto-launch

One-click mode switch — flip between built-in SIM and external firmware in-app

---A Controlled Environment for Navigation and Tuning

iNAV is built around navigation, and so is this integration. Test GPS-driven flight modes and tune the firmware in a simulator that aims to approximate real airframe behavior as closely as possible — without risking hardware on every change. The behavior you see is driven by the same firmware code you'll flash to your aircraft, running against a physics model fitted to real bench data.

Fly position hold, return-to-home, and waypoint missions against simulated GPS

Iterate on PID gains, rates, and filters without crashing real hardware

Probe failsafe behavior by simulating sensor and signal loss

Reproduce tricky navigation and tuning issues in a controlled environment

---Technical Details

MSP V2 link over TCP between simulator and firmware (port configurable in-app)

MSP_SIMULATOR HITL state exchange with the firmware's sensor and navigation stack

Simulated GNSS and magnetometer feed the firmware's estimator and navigation modes

Coordinate transform handled in-engine (Godot Y-up ↔ aviation NED)

Per-sensor failure simulation (gyro, accelerometer, barometer, compass, GPS) for failsafe testing

---Compatibility

You provide your own iNAV install. The iNAV SITL flight controller ships inside the free, open-source iNAV Configurator — there is nothing extra to build. Tested with iNAV 9.0. This DLC does not include or distribute iNAV binaries. Setup details are available in the iNAV project's SITL documentation , and in-app setup notes are included.

The iNAV Configurator can stay connected over TCP while you fly — for live PID tuning and telemetry — alongside the simulator link.

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This DLC is an independent integration. It is not affiliated with, endorsed by, or sponsored by the iNAV project. "iNAV" is a trademark of its respective owners and is referenced here only to identify the firmware this integration connects to.