Line-of-sight guidance law for phantom target generation using unmanned aerial vehicles

Abstract

Electronic attack on air defense radar networks by unmanned aerial vehicles (UAVs) is considered. The radar networks are deceived through generating a coherent phantom track for a radar network to make it track a vehicle that does not exist by using UAVs, each capable of intercepting and sending delayed returns of radar pulses. The inverse problem, to synthesize the UAV trajectory required to create the desired time dependent phantom track, is solved. The result of analysis is applied to construct detailed flyable ranges for an UAV generating a straight and circular phantom track. It is shown that assumption of constant speed of UAV and phantom severely restricts the flyable region where the UAV can fly. Thus constant speed assumption should be relaxed. One of the most common methods of trajectory generation is optimal approach. The important feature of generating phantom track is kinematic and dynamic constraints. These constraints restrict the freedom of UAV. The dimension of optimal control problem is reduced by using these relations and the optimal control problem to generate a phantom converted into a finite dimensional nonlinear programming problem. Optimal control problem to deceive radar networks is formulated and direct single shooting method is used to solve the problem. Finally a new guidance law considering the error of the phantom condition in feedback form is proposed to generate a 3D phantom track. The main idea is motivated by the fact that if a UAV tracks the LOS of a phantom from the radar, then the phantom condition is satisfied. The problem is regarded as a LOS guidance problem in which the UAVs track the LOS of the phantom. First, a LOS guidance law is derived for a pre-specified phantom track by using a single UAV, and then the guidance law is extended to an unspecified phantom trajectory generation problem by multiple UAVs. The LOS guidance law for a specified phantom track for maintaining phantom condition is derived by using the inpu...