Radars can be classified along several axes. The most important classification is by function:
| Type | Function | Characteristics |
|---|---|---|
| Early Warning (EW) radar | warning as early as possible | low frequency, high power, wide beam, low PRF, slow scan (Characteristics of the Early Warning (EW) radar) |
| Surveillance / search radar | building and maintaining the air picture | rotating antenna, L/S/C band, 2D or 3D |
| Height finder | determining the height of targets detected by a 2D radar | nodding antenna; historical, replaced by 3D radars |
| Target Tracking Radar (TTR) | tracking one or a few targets precisely | X-band and higher, narrow beam, high PRF (Target acquisition and tracking) |
| Fire control radar | guiding weapon employment | tracking + prediction + sometimes missile guidance |
| Multifunction radar | searching, tracking and guiding at the same time | phased array that repositions its beam every millisecond |
| Navigation / naval radar | detecting obstacles and coastlines | X/S band, high resolution at short range |
| Weather radar | imaging precipitation | C/S band, Doppler for wind measurement |
| SAR / imaging radar | imaging terrain and targets | synthetic aperture from aircraft or satellite |
| Counter-battery radar | calculating where artillery fire comes from | tracks projectiles, computes the trajectory |
In addition we distinguish radars by waveform — and that classification structures the rest of this chapter:
- Pulse radar (Pulse radar): transmits short pulses and listens in between — measures range directly.
- Pulse-Doppler / MTI (Pulse-Doppler radar and Moving Target Indicator): pulse radar that also processes the Doppler shift — sees moving targets in clutter.
- Continuous wave (CW) (Continuous wave radar): transmits continuously — measures velocity only, no range.
- FMCW (Variation on the CW radar): CW with a frequency sweep — also measures range.
- Passive radar (Passive radar): transmits nothing itself and uses third-party transmitters.