Theoretical and Experimental Study for Dual Camera Photogrammetry Algorithm in Photoelectric Guidance System for Helicopter Landing

Based on the positioning technology of beacon photogrammetry, Dual Camera Photogrammetry (DCP) algorithm was proposed in photoelectric guidance system for helicopter landing. Two Charge Coupled Device (CCD) cameras were used to image four beacons on both sides of the helicopter. Target coordinate systems, camera coordinate systems and image pixel coordinate systems were established. Based on the colinearity of beacon, lens center and beacon image point, a system of linear equations on rotation matrix and translation vector could be obtained. The position and posture parameters of helicopter relative to the landing point could be solved. A photoelectric guidance experiment system for helicopter landing was designed. In high performance Digital Signal Processor (DSP) system, two channels of image signal were processed in real time. The real time helicopter landing guidance information was calculated with DCP algorithm. The simulation experiments show that in the distance interval from 8 m to 13 m, the distance measurement accuracy can reach ±5 cm and the angle measurement accuracy can reach ±3° in the photoelectric guidance experiment system.