Analysis of PNG laws with LOS angular rate delay

Abstract

The performance of proportional navigation guidance (PNG) laws in the presence of line-of-sight (LOS) angular rate delay is discussed in this paper. In the missile systems considered, LOS angular rate is provided by optical image processing means, which in practice leads to a computation delay. Because of the measurement lag, our control objective is to ensure that the missile-to-target range can enter a certain region within finite time. The analysis assumes the LOS angular-rate error caused by the delay is bounded by a known constant when the missile-to-target range is outside the prescribed region. Then, by an appropriate choice of the navigation constant, the control target can be guaranteed theoretically. Next, considering the error bound generally is unknown, to facilitate practical implementation, two different algorithms are further proposed to estimate the LOS angular rate error due to the delay. Moreover, based on such estimates, we discuss how to find the minimum prescribed region.