Abstract: An optical target detecting device and system are disclosed wherein a single lens system projects a beam of infra red radiation and a single lens system picks up target reflections of this single radiation. Additional lens systems including reflectors are disclosed along with the single lens system to increase the frequency of received optical radiation from extraneous sources. Frequency discriminating means eliminate the effects of the extraneous radiations while receiving the optical reflections from the desired target.

Abstract: A coherent optical modulated sensor for use with missiles and the like wherein a series of pulses of optical energy which are intensity modulated by a radio frequency sub-carrier are transmitted to a preselected target having relative motion thereto and wherein returned pulses from the target are received. Phase coherence is effectively maintained by utilizing a single continuously operating local oscillator for down-converting the received detected pulses to a Doppler frequency signal. Target velocity information may be extracted from the Doppler frequency shift induced on the coherent radio frequency sub-carrier of the return pulses.A first channel, or radio frequency sub-carrier channel is provided for receiving the Doppler signal and generating a threshold signal in response to the magnitude of the Doppler signal being equal to or greater than a predetermined magnitude. A second channel (baseband) detects the average direct current power of the received pulse.

Abstract: In apparatus for discriminating targets from clutter, a high threshold circuit for passing only signals with sufficient amplitude and a lower threshold circuit passing signals of a sufficient amplitude to range extent circuitry, which passes only signals within a predetermined duration and which do not have other range signals adjacent thereto, and to frequency extent circuitry, which passes only signals within a predetermined bandwidth and which do not have other frequency signals adjacent thereto. Signals which satisfy the amplitude, range and frequency requirements then provide an output indicative of a target; all other signals are rejected as clutter.