Accurate And Low-Cost Enea Solar Compass For Precision Metrology Of True Azimuth: Instrumental And Smart Versions

The structure and operating principles of a solar compass conceived and realised at the ENEA Laboratories in Frascati are presented. The optical design, the underlying software and the calibration procedure make this instrument a reliable, stand-alone tool with an unprecedented combination of accuracy and cost-effectiveness. In-field operation gives evidence of azimuth determination capability with an accuracy of 0.01 degrees. Exploitation of built-in sensors of smartphones (e.g. GPS, camera, accelerometer) allowed us to move this technology to popular level, providing everybody with a cheap tool of orienteering, far superior to any magnetic compass, despite a reduced accuracy with respect to the original instrument.