In the modern radar systems DSP is used extensively. At the transmitter end, DSP generates and shapes the transmission pulses, controls the antenna beam pattern while at the receiver end, it performs complex tasks like removal of clutter and beam-forming, STAP (space time adaptive processing), etc. DSP is also used in matched filtering and removal of useless information by threshold detection.

The main task of a signal processor in radar is to make decisions. After a signal has been transmitted, the receiver starts receiving return signals. The signal processor places a raster of range bins over the whole period of time. It has to make a decision for each of the range bins as to whether it contains the object or not. This decision making is severely hampered by noise which includes atmospheric noise entering through the antenna, noise due to all the electronics in the radar's signal path.

Other tasks of the signal processor are:

1) Combining information: Surveillance radars, used at airports, communicate with an aircraft's transponder for information like height, flight number or fuel status. Pilots may issue a distress signal via the transponder. The ground radar signal processor combines this data with its own measurements of range and angular direction and plots them on the screen.

2) Forming tracks: DSP of radar return signal can generate a flight vector by correlating the data sets obtained in successive scan cycles. The flight vector indicates aircraft's speed and expected position for the next scan period. Airport radars are capable of tracking hundreds of targets simultaneously, and flight safety depends heavily on their reliability. Military tracking radars use this information for gun laying or guiding missiles into some calculated collision point.

3) Ground Clutter Mapping: Clutter is the collective term for all unwanted blips on a radar screen. Ground clutter originates from buildings, cars, mountains, etc. A clutter map serves to raise the decision threshold in areas where known clutter sources are located. DSP helps to isolate the desired return signal from the clutter.

4) Countering Interference: Interference can be natural or man-made. Natural interference can be heavy rain or hail storms, but also varied propagation conditions. Man-made interference, if created on purpose, is also called jamming and is one of the means of electronic counter measures.