Focusing the difficulty of constructing efficient guidance law for law for missile with passive seeker and maneuvering target A new guidance strategy using only the line-of-sight (LOS) rate measurement was proposed for the missiles with passive seekers. The initial relative range, initial closing velocity and their error boundaries were utilized to obtain their estimations according to the missile-target kinematics. A guidance law based on sliding mode control (SMC) theory was firstly presented, in which the boundary of target maneuvering ability is needed and the chattering phenomenon inevitably exists. In order to overcome the disadvantages above, an expression with a time-varying parameter is introduced to the new guidance law and the stability analysis is included. One of the main features of the proposed guidance strategy is that it reduces the influence of the relative range and the closing velocity on the interception and enhances the effect of LOS rate. The performance of the new guidance law was studied via a computer simulation. The effectiveness of the new guidance law was illustrated through intercepting two kinds of maneuvering target successfully.

A modular design method is proposed for the spacecraft which employs constant thrust on-off jets as actuators. The attitude controller is divided into two sub-controllers based on their functions: a continuous controller for the spacecraft and a pulse-width pulse-frequency (PWPF) modulator for the on-off actuators. The on-off command for the jets is generated by the PWPF modulator which employs the command from the continuous controller as its input. There are eight parameters existing in the attitude controller to be designed. The phase plane method is utilized to analyze the attitude control system and a parameter tuning method is proposed based on the characteristics of the phase locus. This method has the advantage of simplifying the complex non-continuous control system design through combining the continuous controller and the PWPF modulator. Simulation results show that the attitude controller possesses the advantages, such as effectiveness, reliability and good perspective of engineering application.