Homodyne receive architecture in a spatial estimation system

A method of detection of transmitted light reflected from an environment, the method comprising:

• transmitting light from a light source to an environment, the light source including temporal phase noise;
• receiving light reflected from the environment;
• splitting the light reflected from the environment into a plurality of reflected light signals;
• combining a local oscillator signal derived from the light source with each of the plurality of reflected light signals, to produce a plurality of mixed signals, comprising a first mixed signal produced based on a combination of a first local oscillator signal derived from the light source and a first of the plurality of reflected light signals and a second mixed signal produced based on a combination of a second local oscillator signal derived from the light source and a second of the plurality of reflected light signals, wherein the first and second local oscillator signals have different temporal phases induced by the temporal phase noise;
• and
• detecting each of the plurality of mixed signals by a light receiver.

An optical system including:

• at least one optical assembly arranged to:
• receive at least one optical local oscillator signal derived from a light source having temporal phase noise;
• receive an optical remote light signal;
• provide a plurality of optical combined signals based on the at least one local oscillator signal and the remote light signal, wherein each of the plurality of combined signals is formed based on a portion, less than all, of the received light signal, and comprise a first combined signal based on a first temporal phase of the at least one local oscillator signal induced by the temporal phase noise and a second combined signal based on the a second temporal phase of the least one local oscillator signal induced by the temporal phase noise, the second temporal phase different to the first temporal phase;
• a plurality of light receivers arranged to receive the combined signals and provide, based on the received combined signals, a plurality of electrical signals carrying information indicative of at least one characteristic of the received reflected light signal;
• and
• one or more electrical signal processors configured to receive the plurality of electrical signals and provide, based on the received electrical signals, an electrical output signal carrying information indicative of the at least one characteristic of the received light signal.