Range ambiguity resolution is a technique used with medium pulse-repetition frequency (PRF) radar to obtain range information for distances that exceed the distance between transmit pulses.
If the receive signal falls in the same sample number for both PRF, then the object is in the first ambiguous range interval.
If the receive signal falls into sample numbers that are different by one, then the object is in the second ambiguous range interval.
If the receive signal falls into sample numbers that are different by two, then the object is in the third ambiguous range interval.
The detection made using both PRF can be compared to identify the true range.
The optimum pair of PRF used for a pulse-Doppler detection scheme must be different by a minimum of
This makes the range of each PRF different by the width of the sample period.
The process described above is slightly more complex in real systems because more than one detection signal can occur within the radar beam.
The pulse rate must alternate rapidly between at least 4 different PRF to handle these complexities.
Each individual PRF has blind ranges, where the transmitter pulse occurs at the same time as the target reflection signal arrives back at the radar.
Sorting detections in order of amplitude reduces unknown degrees of freedom.
Ambiguity resolution relies on processing detections with similar size or speed together as a group.