High pulse repetition frequency lidar

A laser detection and ranging system, comprising:

• a laser transmitter;
• a receiver;
• and
• a processing circuit,
• the processing circuit being configured to:
• transmit, through the transmitter, a plurality of laser pulses, each at a respective one of a plurality of pulse transmission times;
• detect, using the receiver, a plurality of return pulses, each at a respective one of a plurality of return pulse times;
• and
• estimate a range or a range rate of a target based on the pulse transmission times and the return pulse times,
• each of the pulse transmission times being offset from a corresponding nominal pulse transmission time by a respective pulse position modulation offset,
• the nominal pulse transmission times being uniformly spaced with a period corresponding to a pulse repetition frequency, the pulse repetition frequency being greater than 500 kHz, and
• each pulse position modulation offset having a magnitude of at most one half of the period.

A method for operating a laser detection and ranging system, the method comprising:

• transmitting a plurality of laser pulses, each at a respective one of a plurality of pulse transmission times;
• detecting a plurality of return pulses, each at a respective one of a plurality of return pulse times;
• and
• estimating a range or a range rate of a target based on the pulse transmission times and the return pulse times,
• each of the pulse transmission times being offset from a corresponding nominal pulse transmission time by a respective pulse position modulation offset,
• the nominal pulse transmission times being uniformly spaced with a period corresponding to a pulse repetition frequency, the pulse repetition frequency being greater than 500 kHz, and
• each pulse position modulation offset having a magnitude of at most one half of the period,
• wherein the pulse position modulation offsets define a waveform having a length of at least 1,000 pulses and a peak-to-maximum-side-lobe ratio of at least 500,
• the method further comprising:
• applying a range rate compensation for each of a plurality of hypothetical target range rates,
• calculating a peak cross-correlation for each of the hypothetical target range rates, and
• estimating a target range after applying a range rate compensation for a first range rate, the first range rate being a range rate, from among the plurality of hypothetical target range rates, resulting in maximum peak cross-correlation.