Efficient orientation of a lidar system in a vehicle

A method in a lidar system for scanning a field of regard, the method comprising:

• emitting light using a light source;
• directing the emitted light to scan a field of regard (FOR) of the lidar system in accordance with a scan pattern, including:
• rotating a polygon mirror having a plurality of reflective surfaces about a polygon mirror axis to scan the FOR along a horizontal dimension, wherein the polygon mirror axis is disposed on a plane substantially parallel to plane along which the vehicle moves, and
• pivoting a y-scan mirror along an axis orthogonal to the polygon mirror axis to scan the FOR along a vertical dimension;
• and
• detecting the light scattered by one or more remote targets.

A vehicle comprising:

• a body having a longitudinal axis;
• and
• a lidar system including a set of one or more sensor units, each sensor unit including:
• a light source configured to emit light,
• a receiver configured to detect the light scattered by one or more remote targets, and
• a scanner configured to direct the emitted light to scan a field of regard (FOR) of the lidar system in accordance with a scan pattern, the scanner including:
• a rotatable polygon mirror configured to scan the FOR along a horizontal dimension, the polygon mirror having a plurality of reflective surfaces being angularly offset from one another, and
• a y-scan mirror pivotable along an axis orthogonal to the polygon mirror axis and configured to scan the FOR along a vertical dimension;
• wherein the rotatable polygon mirror of at least one of the sensor units rotates about a polygon mirror axis disposed on a plane substantially parallel to a plane along which the vehicle moves.