• There are two main types of sensor used in autonomous vehicles (seekers and position/attitude sensors) - although not all systems have both. 

          - Aircraft have additional sensors, such as air data sensors that are used to monitor quantities such as the barometric altitude, the angles of attack and sideslip, and the true airspeed. These quantities are used in the flight control system to improve the handling properties of the aircraft, but could be available for use in a guidance system.

• There are four main types of seeker: 

         - Passive Non-imaging - Infrared or Laser detector (Gimballed with Rate Gyro) .
         - Passive Imaging - Infrared or visible band.
         - Active Non-imaging - Standard radar (cm or mmW range profiling) or Ladar.
         - Active Imaging - Imaging radar (SAR or DBS) or Burst Illumination Laser Imaging.

• Passive sensors produce accurate angle information but inaccurate range estimates. 
• Active sensors produce accurate ranges but non-imaging sensors only have coarse angular resolution.