Doublet pulse coherent laser radar for precision range and velocity measurements

A system for determining a range and velocity of a distant object, the system comprising:

• a laser for creating a doublet pulse waveform of coherent light, wherein the doublet pulse waveform comprises two pulses;
• at least one optical element connected to the laser for directing the double pulse waveform toward the distant object and for receiving a reflected doublet pulse waveform returned from the distant object;
• a detector circuit connected to the optical element for detecting the reflected doublet pulse waveform;
• a time delay measuring circuit connected to the detector circuit for measuring a time delay between the doublet pulse waveform and the reflected doublet pulse waveform wherein the time delay defines the range of the distant object;
• a phase measuring circuit for measuring a phase difference between first and second pulses in the reflected doublet pulse waveform, and for determining the velocity of the distant object from the phase difference, the phase measuring circuit comprising
• a transmit correlation circuit for creating a transmit phase map of the transmitted pulses,
• a receive correlation circuit for creating a receive phase map of the received pulses, and
• a filter circuit for creating a conjugate product of the transmit phase map and the receive phase map to determine the velocity.

A method for determining a range and velocity of a distant object, the method comprising the steps of:

• (a) creating a doublet pulse waveform of coherent light, wherein the doublet pulse waveform comprises two pulses;
• (b) directing the double pulse waveform toward the distant object;
• (c) receiving a reflected doublet pulse waveform returned from the distant object;
• (d) detecting the reflected doublet pulse waveform;
• (e) measuring a time delay between the doublet pulse waveform and the reflected doublet pulse waveform wherein the time delay defines the range of the distant object;
• (f) measuring a phase difference between first and second pulses in the reflected doublet pulse waveform, and determining the velocity of the distant object from the phase difference.