Infrared Sensors

Infrared Sensors

Hardware support for previous, currently in use and future infrared boards.

Infrared Stabilisation Principle

The paparazzi autopilot uses infrared thermopiles for primary attitude sensing. The theory is that at zero bank or pitch angle, the difference in the heat between the two sensors should be zero, and at 90 degrees it should be maximum. From this relationship a linear regression is made and angles are calculated during flight.

Each pair of sensors measures one axis, a minimum of 2 pairs must be used to measure pitch and roll but best results are obtained thru the use of a 3^rd pair on the vertical axis. Since the output signal from each sensor pair is proportional to both the attitude and the weather/terrain, systems with only x-y sensors require a ground calibration and may not provide accurate angle calculations as the aircraft travels over terrain with different IR radiation.

Hardware Architecture

Horizontal Board

Vertical Board

Thermopiles

The Thermopiles are:

Manufacturer Part Number: MLX90247-ESF-DSA (Digi-Key: MLX90247-ESF-DSA-ND)

Description: IC SENS THERMOPILE W/THERM TO-39