Mirror movement and laser shoot pattern compensation for frequency-modulated continous-wave (fmcw) lidar

A method of compensating a scanning system, the method comprising:

• transmitting a frequency modulated continuous wave (FMCW) light beam into a field of view, wherein the FMCW light beam comprises a plurality of frequency ramps having a chirp rate that is variable;
• driving a scanning structure to rotate about a scanning axis such that a deflection angle of the scanning structure continuously varies over time, wherein the scanning structure is configured to scan the field of view with the FMCW light beam;
• measuring the deflection angle of the oscillator structure as the deflection angle varies over time;
• generating position information based on the measured deflection angle;
• and
• varying the chirp rate of the plurality of frequency ramps based on the position information.

A scanning system, comprising:

• a transmitter configured to transmit a frequency modulated continuous wave (FMCW) light beam into a field of view, wherein the FMCW light beam comprises a plurality of frequency ramps including up-chirps and down-chirps that are matched into up-down chirp pairs, each up-down chirp pair including one up-chirp and one down-chirp;
• a scanning structure configured to oscillate about a scanning axis such that a deflection angle of the scanning structure continuously varies over time, wherein the scanning structure is configured to oscillate in an angular range between a first maximum deflection angle and a second maximum deflection angle;
• and
• a controller configured to segment the angular range into a plurality of sub-angular ranges and assign each up-down chirp pair of the FMCW light beam to a different sub-angular range of the plurality of sub-angular ranges, wherein each up-down chirp pair comprises an up-chirp transmitted in an assigned sub-angular range during a first scanning movement of the scanning structure and a down-chirp transmitted in the assigned sub-angular range during a second scanning movement of the scanning structure.

A method of compensating a scanning system, the method comprising:

• transmitting, by a transmitter, a frequency modulated continuous wave (FMCW) light beam into a field of view, wherein the FMCW light beam comprises a plurality of frequency ramps including up-chirps and down-chirps that are matched into up-down chirp pairs, each up-down chirp pair including one up-chirp and one down-chirp;
• driving a scanning structure to oscillate about a scanning axis such that a deflection angle of the scanning structure continuously varies over time, wherein the scanning structure is configured to oscillate in an angular range between a first maximum deflection angle and a second maximum deflection angle;
• segmenting the angular range into a plurality of sub-angular ranges;
• assigning each up-down chirp pair of the FMCW light beam to a different sub-angular range of the plurality of sub-angular ranges, wherein each up-down chirp pair comprises an up-chirp transmitted in an assigned sub-angular range during a first scanning movement of the scanning structure and a down-chirp transmitted in the assigned sub-angular range during a second scanning movement of the scanning structure;
• and
• controlling the transmitter to transmit each up-down chirp pair at their assigned sub-angular range.