SEARCH FOR SMALL-SIZED OBJECTS ON THE UNDERLYING SURFACE IN FRONT OF THE AIRCRAFT

Abstract

The method of searching of small-sized ground or surface objects with unknown coordinates is proposed. The search is carried out using the thermal imaging or other IR remote sensing system (RS) of underlying surface (US) in front of the aircraft. The small size of objects requires the use of narrow fields of view for detection and recognition at ranges that allow to carry out operational actions, which are provided for by the flight mission for rescue operations on land and at sea or for aircraft emergency landing on an unprepared site. Two tasks are solved: 1) the maximization of the guaranteed bandwidth of objects searching on US with given characteristics of RS and aircraft speed; 2) the determination of the optimal characteristics of remote sensing systems and aircraft speed for a given search bandwidth of the US.A periodic change in the azimuthal orientation of the narrow field of view (automatic scanning of the US by the field of view of the IR system) is used for solving given tasks. For a given operating range of the IR system the proposed algorithm ensures that the pilot or operator can view the runway on US without “dead” zones (unseen areas). The optimal value of the search effort corresponding to the detection and recognition of objects is determined. The proposed algorithm implements symmetrical scanning (scanned areas of the same shape are formed to the left and right of the flight path on US). The symmetric scanning equation is derived for prediction search efficiency. The solution of given equation makes it possible to find the dependence of the guaranteed search bandwidth on the operating range of ranges in which detection and recognition are possible for given weather conditions. The examples of using the derived equation when searching for objects in simple and difficult weather conditions are given.