Distributed Mixed-Power Fixed-Time Cooperative Guidance for Multiple Aircraft with Terminal Line-of-Sight Angle Constraints

Cooperative interception by multiple aircraft requires coordination of physical event times and terminal line-of-sight (LOS) directions under strongly coupled three-dimensional motion. A limitation of predictor-based designs is that agreement of estimated terminal times is often interpreted as simultaneous interception without an explicit predictor-to-event error bound. This paper develops a distributed mixed-power fixed-time guidance framework that comprises point-mass kinematics and ideal inner-loop tracking. An exact spherical-coordinate model retains the azimuth–elevation coupling terms. The radial predicted terminal time (RPTT) is used as the distributed coordination state, and a local bound links RPTT to independently detected interception events. A mixed-power consensus protocol is analyzed for a fixed graph and a finite set of connected undirected switching graphs using a common Lyapunov function. An inertial-frame fixed-time observer estimates the unmeasured target acceleration, while a C2-regularized nonsingular fast terminal sliding-mode law regulates the terminal LOS azimuth and elevation. The analysis distinguishes nominal exact fixed-time consensus, perturbed practical fixed-time reachability, and exponential convergence inside the regularization layer. Four-aircraft simulations produced a 0.435 ms independent event-time spread and terminal LOS errors below 0.046°. Relative to a peak-matched single-power protocol, the RPTT agreement time was reduced by 34.3%, with a 0.58% increase in total control effort. The results support the method’s use as a guidance-layer coordination design within the stated sensing, communication, and inner-loop assumptions.