Scanning laser for a scanning laser radar

DETAILED DESCRIPTION The present invention disclosed and claimed herein provides an optical radar system for transmitting a first coherent signal and receiving the reflected portion thereof.
The transmitter has a means for generating the first coherent signal at an angle that is varied by a first steering means.
The first coherent signal is then collimated through a collimating means, processed through a modulating means and then transmitted.
The receiver has means for generating a second coherent signal that is divided into a plurality of local oscillator beams.
The angle of each of the local oscillator beams is varied by a second steering means for input to a mixing means.
The mixing means sums together one of the local oscillator beams with a corresponding return signal, the corresponding return signal being comprised of the reflected portion of the transmitted first coherent signal.
The output of the mixing means is input to a first detecting means.
The frequency of the first coherent signal and the second coherent signal are sampled by a first and second sampling means, respectively.
A summation means sums the outputs of the first and second sampling means for input to a second detecting means.
The second detecting means detects the frequency difference between the first and second coherent signal and generates a control signal to adjust the frequency of the first coherent signal.
For heterodyne operation a selected frequency difference is generated whereas for homodyne operation a zero frequency difference is generated.
A synchronization means coordinates the first and second steering means such that each of the local oscillator beams will overlap with each of the corresponding return signals at the detecting means.
A processing means processes the output of the first and second detecting means to provide information about the return signal.