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Welcome to the AntTracker

 Eric Stockenstrom - First code June 2017

See RC Groups - Build a Tracker

This application reads serial telemetry sent from a flight controller or GPS. The module calculates where an airbourne craft is relative to the home position. From this it calculates the azimuth and elevation of the craft, and then positions azimuth and elevation PWM controlled servos to point a direction high-gain antenna for telemetry, RC or/and and video.

If your servo pair is of the 180 degree type, be sure to comment out this line like this: //#define Az_Servo_360

Note that the elevation (180 degree) servo flips over to cover the field-of-view behind you when the craft enters that space.

If your servo pair comprises a 360 degree azimuth servo and 90 degree elevation servo, be sure to un-comment out this line like this: #define Az_Servo_360

The code is written from scratch, but I've taken ideas from Jalves' OpenDIY-AT and others. Information and ideas on other protocols was obtained from GhettoProxy by Guillaume S.

The target board is an STM32F103 "Blue Pill", chosen for its relative power, small size and second (multi) serial port(s) for debugging. The arduino Teensy 3.x is also suitable, but much more expensive. The arduino mini pro or similar can be made to work but is not recommended for perfomance reasons and lack of second (debugging) serial port.

To use the AntTracker, position it with the antenna facing the centre of the field in front of you. Position the craft a few metres further, also facing the same heading for take-off. Tracking (movement of the antenna) will occur only when the craft is more than minDist = 4 metres from home because accuracy increases sharply thereafter.