| Summary: | 博士 === 中正理工學院 === 國防科學研究所 === 87 === Inertial Navigation System(INS) is an autonomous, self-contained and non-radiating equipment suitable for navigation of military vehicles. However, the INS position errors grow with time, making it improper for long time navigation. Without using high precision inertial instruments, we can promote the INS and maintain its accuracy for long time operation by incorporating the Global Position System(GPS) into it. Building up an accurate error model of GPS and INS and well designing the Kalman Filter(KF) are critical to the successful integration of GPS and INS. From the practical point of view, too many KF state variables will increase the burden of navigation computer and the memory requirement. In this research, we omit some state variables concerning the inertial instrument biases and platform attitude errors. To compensate for the effect resulting from the model reduction, we strengthen the process noise of the velocity errors states. Numerical simulations and error covariance analysis are conducted and the results show that the reduced order KF is just as good as the conventional KF design.
The guidance command of proportional navigation guidance(PNG) law is proportional to the line of sight rate(LOSR) of the missile and the target. Although the PNG features the ease of implement and robustness, it often tends to saturate the lateral acceleration at the final stage on the intercept which results in large miss distance, the PNG is considered only to be suitable for the target at the constant speed or low maneuver. At present, numerous advanced guidance laws have been devised by applying optimal theory and estimation theory to intercept targets with high maneuver. However, they adopted the spirit of PNG design. It is found that if the missile has large initial heading error or is fired in short range, the advanced guidance laws will have poor intercept performance. In this work, two new terminal guidance laws (called Modofied Aiming Point Guidance Laws and Aiming Line Rate Guidance Law) are developed for the air-to-air missiles. The collision course of the guidance laws is chosen as the line connecting the position of missile and the predicted impact point. The proposed guidance laws have features of short intercept time, low lateral acceleration at the final stage of engagement, small miss distance, and large firing envelop. The superior performance of these two guidance laws makes themselves attractive to the design of missile guidance of the next generation.
|
|---|
