考虑信噪比影响的非线性H_∞制导律设计

针对导弹对目标拦截问题,考虑测量信号信噪比影响,以非线性H∞控制理论为基础,应用Lya-punov函数稳定性的分析方法设计了具有强鲁棒性的非线性制导律。首先,以弹-目相对距离和相对速度为变量,并将目标机动视为扰动,建立弹-目相对运动的非线性数学模型。其次,基于零化弹目相对距离的思想,针对拦截过程中测量噪声的影响问题,提出了非线性H∞稳定控制策略,得到连续的非线性末制导律,并分析了信噪比与制导律参数的关系,对测量信号信噪比提出了要求。同时,严格证明了制导系统的稳定性,且无需求解HJI偏微分方程。仿真结果表明,这种制导律对大机动目标具有较强的鲁棒性和适应性,同时能获得良好的制导精度。

Design of nonlinear H∞ guidance law considered the effect of SNR

According to the character of the missile intercepting target,and considering the SNR of measuring signal,a new continuous nonlinear H∞guidance law with robustness was proposed by Lyapunov-like approach based on H∞ control theory.First of all,the distance and distance rate were chosen as state variables,the mathematic model was built according to the relationship between the missile and target whose maneuver was introduced as disturbance.Then,based on the method of zeroing the rate of the line-of-sight angle and considered the effect of measuring error,a nonlinear H∞control strategy was contrived to obtain the continuous nonlinear guidance law.At the same time,the relationship between SNR and parameters was analyzed,also the SNR requirements are demanded.The stability of guidance system was strictly proven by Lyapunov stability theory instead of solving the HJI partial differential equation.Finally,the simulation shows that the guidance law designed has strong robustness and adaptability to target maneuver,and it is capable of achieving better precision of guidance.