corresponding angle u03c6 between line 48 and sight line 8 if detector sight line 8 is moved because of vibration or movement of the platform to which the sensor is mounted angles u03b8 and u03c6 will change since the reference plane 47 remains in the same position it is necessary to adjust for the change in angles before such an adjustment can be made however one must determine the amount of movement of detector 1 this is accomplished through the use of motion detector 12 as shown in fig4 the motion detector contains three orthogonal gyroscopes 52 and three orthogonal accelerometers 54 the motion detector 12 generates a signal which passes along line 53 to processing unit 20 we prefer also to provide a second line 55 from the motion detector to a servo motor 56 and associated processor the servo motor 56 responds to the information received from motion detector 12 by adjusting the optical line of sight 8 of lens 5 this can be done by moving the support 57 on which lens 5 has been mounted within the detector 1 we provide a sensor array 58 which generates a signal in response to light passing from the scene through lens 5 that signal is directed along line 16 to the processing unit the detector is mounted on platform 6 one may provide an additional servo motor 60 controlled by the processing unit through input 62 servo motor 60 is used to make major changes in the.