Infrared spot tracker

Claim 1

Apparatus that provides tracking of a source of infrared illumination from at least one trainee's weapon to continuously monitor its movement for continuously identifying the aiming position coordinates of said trainee's weapon, comprising: a reflective screen; a source of infrared energy from at least one trainee's weapon having a beam output to directly illuminate a spot on any position of said screen; optical means having a field of view and having said infrared illuminated spot within its field of view, for receiving energy from said infrared energy source reflected by said screen, transmitting the energy and focusing it at a preselected distance optically downstream; electrically-biased means at said preselected distance optically downstream said optical means for sensing said energy transmitted by said optical means and providing two pairs of opposing output signal voltages from a substantially two-dimensional surface with first and second outputs being opposite one another on said two-dimensional surface, and third and fourth outputs likewise being opposite one another that identify in each orthogonal location whereat the energy is sensed; and processing means comprising a separate electronic channel for receiving each of said output signal voltages from said electrically-biased means and each channel including a transimpedance amplifier coupled to its respective output of said electrically-biased means, a band-pass filter coupled to its transimpedance amplifier, a full-wave rectifier coupled to its transimpedance amplifier, and a low-pass filter coupled to its full-wave rectifier, and wherein said low-pass filters of said channels are coupled to an analog-to-digital converter for determining therefrom the orthogonal location of said spot on said screen.