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ABSTRACT Considering an unpowered missile diving to intercept a maneuvering target, a novel fixed‐time guidance and attitude control algorithm is proposed. First, the second‐order derivatives of the aerodynamic angles are directly linked to the fin deflections, which can avoid the tracking of missile body angle rate instruction in the traditional methods. Second, a novel fixed‐time time‐varying parameter nonsingular terminal sliding mode guidance law is proposed, which can avoid control input singularity without switching to the polynomial form when the error approaches the origin. Third, a new global time‐varying sliding mode with a predefined convergence time and analytical solution is developed to design the attitude controller. The system states are proved to be fixed‐time convergence based on the Lyapunov stability theory. Six‐degree‐of‐freedom simulations are conducted to validate the superiority of the proposed algorithm in terms of miss distance, impact angle error, interception time and control energy. [ABSTRACT FROM AUTHOR]

This article addresses the Bayesian filtering problem for a class of nonlinear systems under multistep randomly delayed and lost measurements. A new measurement model is established that can characterize the random delay and loss of measurement data. First, an augmented Gaussian mixture filter framework is developed in the case of random delay of measurement data; the posterior probability density function after state augmentation is calculated by marginalizing over delay variables to extract accurate information from delayed measurements. The implementation of the filter is transformed into the computation of nonlinear numerical integrals. Second, under the proposed framework, novel expressions of the mean and covariance are generated by propagating the measurement taken at the previous moment in the event of no new measurement being received. Finally, we present two simulation examples for estimating system states, and the results demonstrate the effectiveness and superiority of our proposed filter. [ABSTRACT FROM AUTHOR]

With the rapid development of the information age, the need for high-resolution reconnaissance and surveillance is becoming more and more urgent. It is necessary to develop photoelectric pods with a high-precision stabilization function, which isolate the influence of external disturbance and realize the tracking of maneuvering targets. In this paper, the internal frame stabilization loop control technique is studied. Firstly, the mathematical models of the current loop are established. Secondly, the friction model, parametric model, and mechanical resonance model of the system are identified. Finally, a fourth-order tracking differentiator and a fifth-order extended state observer are designed. Through simulation verification, the stability performance of HO-ADRC, increasing by 145.17%, is better than that of PID. In terms of disturbance suppression and noise removal ability, HO-ADRC is also better than PID. [ABSTRACT FROM AUTHOR]

A nonsingular distributed cooperative terminal guidance law is proposed for the problem of multiple missiles attacking ground stationary target simultaneously. By selecting the estimated attack time as consistency variable, the consistency algorithm is combined with nonsingular guidance law, and the limitation caused by the assumption of small angle and specified attack time can be avoided. The closed-loop stabilities of the consensus error and the lead angle are proved based on Lyapunov stability theory, which can verify the effectiveness of the proposed distributed cooperative guidance law. Numerical contrast simulations further verify that the miss distance of the designed guidance law under large initial lead angle is one order of magnitude smaller than that of the compared distributed guidance law, demonstrating the effectiveness and superiority of the proposed guidance law.

Aiming at the problem of multi-missile cooperative interception of maneuvering targets, two different cooperative guidance laws are designed based on the time-to-go. For the scenario of multi-missile distributed communication, a distributed cooperative proportional guidance law with time-varying navigation coefficients is designed based on the idea of biased proportional guidance. For the scenario of specified attack time, based on the form of time-to-go under constant lead angle, a sliding mode guidance law with a specified attack time is designed by using sliding mode control and nonlinear disturbance observer. Simulation results show that the two guidance laws proposed in this paper can effectively carry out cooperative attack or sequential attack against maneuvering targets.

Weapon target assignment (WTA) is a typical problem in the command and control of modern warfare. Despite the significance of the problem, traditional algorithms still have shortcomings in terms of efficiency, solution quality, and generalization. This paper presents a novel multi-objective evolutionary optimization algorithm (MOEA) that integrates a deep Q-network (DQN)-based adaptive mutation operator and a greedy-based crossover operator, designed to enhance the solution quality for the multi-objective WTA (MO-WTA). Our approach (NSGA-DRL) evolves NSGA-II by embedding these operators to strike a balance between exploration and exploitation. The DQN-based adaptive mutation operator is developed for predicting high-quality solutions, thereby improving the exploration process and maintaining diversity within the population. In parallel, the greedy-based crossover operator employs domain knowledge to minimize ineffective searches, focusing on exploitation and expediting convergence. Ablation studies revealed that our proposed operators significantly boost the algorithm performance. In particular, the DQN mutation operator shows its predictive effectiveness in identifying candidate solutions. The proposed NSGA-DRL outperforms state-and-art MOEAs in solving MO-WTA problems by generating high-quality solutions. [ABSTRACT FROM AUTHOR]