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.

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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

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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

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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

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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.