An Angle-Based Control Law for Target Location Stabilization in 3-D Space

Many aerial tasks require an aircraft to move to a target location autonomously. However, existing linear control laws usually require absolute/relative position measurements with respect to the target location, and nonlinear distance-only control laws merely guarantee local convergence to the target location. Motivated by this challenge, we propose a 3-D angle-based control law such that an aircraft can autonomously move to the target location described by three angle constraints with respect to three ground stations. The proposed control law only needs bearing measurements and communication between the aircraft and the ground stations. By decoupling the dynamics of the angle errors, the proposed control law for single integrator dynamics guarantees global convergence to the target location. Three angles are controlled to converge, which are independent of the orientation of the aircraft's coordinate frame. This control law is more accessible and reliable than those based on relative position. Simulations are conducted to validate the effectiveness of the proposed control law.