Monopulse-radar angle tracking in noise or noise jamming

In many monopulse radars, feedback in the angle-tracking servo system is taken to be directly proportional to the monopulse ratio. In those radars, monopulse measurements are conditioned on simultaneous occurrences of receiver sum-channel video exceeding a detection threshold: if a detection fails to occur, the measurement is ignored, and the angle-tracking servo is made to coast. Such conditioning is shown to be necessary in order that the noise power be finite in the servo feedback. The conditional mean value and conditional variance of the monopulse ratio are derived and quantified in terms of threshold level as well as signal-to-noise ratio. The formulation permits the noise covariance between receiver difference and sum channels to be complex rather than only real-valued, so that the sources of noise jamming are not required to be positioned in the receiving-antenna mainlobe and to be copolarized with the antenna response there. Nonfluctuating and Rayleigh-fluctuating target cases are considered and compared, and fluctuation loss is quantified     

Effect of Sensor Errors on Automatic Gunfire Control

A formal approach is introduced toward mathematically relating errors in processed sensor data to their impact on error in gunfire of ground based, antiaircraft defense systems. An initial budget for sensor errors is formulated in terms of the accuracy requirements imposed upon the gunfire. The analysis is applicable to gun sites that are remotely located from the sensor as well as to colocated gun sites. Here, the radial components of sensor errors (along the sensor track line) are found to affect the target-miss distance of a remote gun by at least an order of magnitude more than their effect on the miss distance of a colocated gun. However, the effects of the traverse components of sensor errors (across the sensor track line) are found comparable in magnitude between remote and colocated guns.     

Fade Probabilities: Measures for Predicting Search-Radar Performance

By itself, the cumulative probability of detection has been inadequate for accurate performance prediction of the AN/APQ-159, airborne, F-5 radar. For this reason, quantitative measures of fading of target echoes were formulated. Probabilities of 10-percent fade and of triple miss are defined here, and algorithms, as well as some important general properties, are derived for their efficient computation by machine in terms of the single-scan probabilities of detection. Both probabilities are cumulative quantities, dependent on the total number of independent looks at the target.