UAV Circumnavigating an Unknown Target Under a GPS-denied Environment with Range-only Measurements

TL;DR

This paper presents a control algorithm enabling UAVs to orbit an unknown target at a fixed distance in GPS-denied environments using only range measurements, with a novel estimator replacing the need for range rate data.

Contribution

It introduces a two-step control design that first assumes range and range rate measurements, then eliminates the need for range rate using a sliding-mode estimator, applicable to GPS-denied UAV navigation.

Findings

Successful control algorithm design for GPS-denied circumnavigation

Range-only measurement sufficiency demonstrated with estimator

Bounded control inputs ensured during operation

Abstract

One typical application of unmanned aerial vehicles is the intelligence, surveillance, and reconnaissance mission, where the objective is to improve situation awareness through information acquisition. For examples, an efficient way to gather information regarding a target is to deploy UAV in such a way that it orbits around this target at a desired distance. Such a UAV motion is called circumnavigation. The objective of the paper is to design a UAV control algorithm such that this circumnavigation mission is achieved under a GPS-denied environment using range-only measurement. The control algorithm is constructed in two steps. The first step is to design a UAV control algorithm by assuming the availability of both range and range rate measurements, where the associated control input is always bounded. The second step is to further eliminate the use of range rate measurement by using an estimated range rate, obtained via a sliding-mode estimator using range measurement, to replace actual range rate measurement. Such a controller design technique is applicable in the control design of other UAV navigation and control missions under a GPS-denied environment.