The development of a target-lock-on optical remote sensing system for unmanned aerial vehicles

Abstract

The use of unmanned aerial vehicles (UAVs) in various military and civil applications is the subject of much current attention. With recent developments in personal computer technology, and the availability at affordable cost of peripherals, and electronic and optical sensors, UAVs for long endurance missions, with flight autonomy beyond the visual range, have become an attractive challenge for study in universities and research institutes. This paper describes the development of a target-lock-on optical remote sensing system to be used as a payload in a university-class UAV. To accomplish autonomous way-point navigation for the conduct of optical sensing surveillance, a gimbaled-platform with servo control and an Attitude and Heading Reference System (AHRS) navigation system for UAV position and attitude measurements have been developed. The UAV also utilises a Global Position System (GPS) receiver, a pressure altimeter, gyroscopes and an electric compass. A novel mathematical model is proposed to calculate the optimal parameters for orientating the CCD camera line of sight with a ground target, designated in real time from a ground control station. Both ground and flight test results have demonstrated the feasibility of the navigation control scheme and the UAV's ability to conduct ground target acquisition and image transmission.

A Stochastic Approach to Noise Modeling for Barometric Altimeters

“…Barometric altimeters can be used for measuring the height of an object above a given reference level, e.g., the sea level—a popularly used term for this height is pressure altitude. Common applications are, e.g., in avionics, where barometric altimeters can help in stabilizing the vertical position and velocity of a flying object [ 1 , 2 ]. Recently, barometric altimeters have been considered for interesting human-centric applications, such as personal navigation and human motion tracking and monitoring.…”

Development of a Low-Cost Attitude and Heading Reference System Using a Three-Axis Rotating Platform

“…For the development of a low-cost AHRS, the accuracy is not a significant issue, but the reliability and practicability are of greater concern. From our experience, the acceptable attitude errors for the navigation of a small UAV are within 3° [ 13 ]. Therefore, a three-axis rotating platform with acceptable precision is adequate to calibrate and validate the low-cost AHRS.…”