Hardware
- STM32F401xD/E · Cortex-M4
- BLACKPILL_F401CC target
- USART1 · telemetry / RFD
- USART2 · autopilot
- 3.3 V TTL UART
- 115200 baud in the current configuration
STARTX / NAVIGATION SYSTEM
NO
GPS.
A dedicated STM32F401 MAVLink module that sits between telemetry and the autopilot and provides a controlled backup positioning path when the primary GNSS source is unavailable.
STM32F401MAVLink 1 / 2ArduPilot2 × UART
01 / ROLE IN THE SYSTEM
ONE NODE.
TWO DATA PATHS.
StartX NO GPS is not a replacement for the flight controller. It is an independent MAVLink component that routes telemetry and can introduce a validated backup GPS_INPUT when the integration scenario requires it.
Telemetry / RFDExternal communication link
↔StartX NO GPSRouting + backup position
↔ArduPilotFlight controller
02 / SYSTEM BEHAVIOUR
BACKUP ONLY
WHEN REQUIRED.
01 / START
No valid GNSS at startup
After the configured delay, the module can provide the validated backup GPS_INPUT required by the specific ArduPilot integration.
02 / FLIGHT
GNSS is lost in operation
If the primary valid GNSS source disappears after takeoff, the module can transition to the defined backup positioning path without a manual source switch.
03 / RECOVERY
Valid GNSS returns
When the autopilot again reports a valid 3D GNSS fix, the backup source is disabled and the system returns to its primary positioning source.
04 / CONTROL
Independent MAVLink component
The backup logic can be integrated and bench-tested separately from the primary GNSS hardware.
Important: the module controls the backup virtual GPS source. Arming, motor start and transitions to autonomous flight modes remain under ArduPilot and the configuration of the aircraft.
03 / ENGINEERING BASIS
HARDWARE.
PROTOCOL.
VALIDATION.
Integration
- MAVLink component ID 191
- HEARTBEAT and STATUSTEXT
- MAVLink parameter protocol
- Autopilot GNSS-state monitoring
- GPS_INPUT for the backup scenario
- Bench validation for the target configuration
04 / VALIDATION
CONFIGURATION
MATTERS.
EKF
Estimator configuration
The backup path depends on EKF source configuration and on how the target aircraft is expected to behave when GNSS quality changes.
ARDUPILOT
Version and parameters
Arming checks, failsafe behaviour, GPS source selection and flight modes are verified against the actual ArduPilot configuration.
PLATFORM
Aircraft-specific behaviour
Multirotor, fixed-wing and other platforms do not share identical assumptions. The module is validated as part of a defined system, not as a universal GNSS substitute.
STARTX NO GPS