| 摘要 |
Apparatus and method for determining velocity and range of a target within a field of view. A velocimeter and tracker (10, 100) includes a laser (12, 12') that produces modulated coherent light, a portion of which illuminates targets (22, 22') coming into a field of view (24, 24') of the velocimeter and tracker. Coherent light reflected from the target travels back along a detection path toward a phase conjugate mirror (40, 40') as a probe wave (26, 26'). A higher intensity portion of the coherent light produced by the laser is split into equal parts that are directed toward the phase conjugate mirror from opposite directions and interact with the probe wave to produce a phase conjugate light signal that travels back along the detection path and is also reflected from the target. Light reflected by the target experiences a Doppler phase shift as a function of target velocity. First, second, and higher order phase shifted signals reflected from the target are imaged on photo diodes (68, 68'), producing an electrical signal having components corresponding to the frequency differences of the various order light signals. As a function of the sums and differences of the frequency components of the electrical signal, the range and velocity of the target are determined.
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