Unmanned Aerial Vehicle Path Following for Target Observation in Wind

Abstract

This work provides flight-path geometry, guidance laws, and synchronous camera angles to observe a ground target from an unmanned aerial vehicle. The observation of the target is affected by wind, aircraft performance, and camera limits. Analytic expressions are derived for paths that result in constant line-of-sight orientation of the target relative to the aircraft body frame. Using minimal heuristics, a guidance law based on "good helmsman" behavior is developed and implemented, and stability of its integration with aircraft dynamics is assessed. An observer estimates wind data, which are used to orient path geometry about the target. Results are demonstrated in high-fidelity simulation.= body-fixed axes system x N , y E , z D = navigation axes system x, y, z = position coordinateŝ x = observer state vector y s = cross-track error α = angle of attack β = angle of sideslip ζ = bearing angle of target from the aircraft κ = camera pan angle κ(s) = curvature of desired path at position s λ = camera tilt angle ρ = radius of curvature φ = bank angle χ = course χ s = desired course on orbit χ w = wind direction ("from" convention) ψ = heading ψ p = bearing angle of aircraft from the target ("clock angle" relative to target) ψ w = wind vector orientation (ψ w = χ w + π ) Subscripts and Supersripts ac = aircraft center of gravity b = body-fixed reference frame . Member AIAA. c = command e = Earth reference frame icpt = Intercept m = measured s = Serret-Frenet reference frame tgt = target w = wind ∧ = estimate

Development and testing of the intercept primitives for planar UAV engagement

“…This guidance logic is similar to proportional navigation (PN) law against a virtual stationary target that moves every time-instant. [8] obtained differential geometric expressions for orbits that allow an aircraft to keep flight paths that result in constant line of sight with respect to the aircraft body-fixed frame. [9] presented a synthetic-waypoint guidance algorithm which attempts to emulate pure pursuit (PP) guidance law and showed that its performance depends on a guidance parameter -the desired time horizon for the vehicle to initiate a response to flight path changes.…”

Target Tracking in 3-D Using Estimation Based Nonlinear Control Laws for UAVs

“…Many guidance and control techniques have been investigated by researchers: vector field approach [4][5][6][7][8][9][10], line of sight algorithms [11], Serret-Frenet representation based methods [6,12], feedback linearization [13][14][15] and thebackstepping approach [16][17][18]. This paper explores the implementation of a nonlinear guidance and control design technique for a UAV to track a target in 3D environment.…”

Turning Direction Determination using Error Dynamics-Based Guidance Law for Stationary Target Observation

“…Rysdyk introduced ''good helmsman'' behavior to design a guidance law for the target observation. 5) Prevost et al proposed receding horizon model predictive control (MPC) for tracking ground targets using fixed-wing UAVs. 6) Kim et al proposed a nonlinear MPC framework for cooperative standoff tracking of a ground vehicle for fixed-wing UAVs.…”