Angle Estimation Accuracy with a Monopulse Radar in the Search Mode

This paper is concerned with the accuracy of singlehit angle estimation by a monopulse radar in the search mode. The system analyzed is an amplitude comparison estimator. Off-axis targets are considered. The effects of narrow-band Gaussian receiver noise on the sum and difference signals are considered. An asymptotic expansion for the angle estimate is derived which converges for SNR´s of 12 db or greater. The mean and the standard deviation of the angle estimate are found. These statistics are given in terms of antenna radiation patterns, true target angular position, SNR, and noise statistics. It is found that the expected value of off-boresight angle estimates is equal to the true angle of the target. Further, the standard deviation of the angle estimate increases as the target is moved off boresight. This increase is greater than would be expected from the decrease in antenna gain due to off-axis operation. Correlation between noise in the sum and difference channels reduces the off-axis errors.