TABLE OF CONTENTS How accurately can we measure range and velocity?
Can we distinguish closely spaced targets?
How much freedom do we have to improve radar performance?
How do we choose waveforms that tell us as much as possible about the properties of the target?
In Chapter 4, we established that the correlation receiver (or matched filter) provides the optimum method of detecting a stationary target. Detectability is unaffected by the form of the transmitted pulse. All that matters is the ratio of the signal energy E to noise power per unit bandwidth N both calculated at the input to the receiver. The signal-to-noise ratio at the output of the correlation receiver is then given by E/N. However, there are other important aspects of system performance for which the signal shape does become important. These include the resolution, ambiguity and accuracy [ ] of the measurements made by the radar.
The resolution of a radar system is a measure of its ability to separate closely spaced targets in range or velocity. These can be treated separately, but simultaneous measurement of both range and velocity is often required. In this case there is an unavoidable uncertainty, so that two targets at different ranges and velocities may in principle and practice be indistinguishable.
Ambiguity occurs if the output of the receiver from a single target contains multiple peaks that can be mistaken for other targets. Such peaks may be caused by noise, but may also be produced by the...
