# US 2023/0266451 A1 · Online lidar-to-ground alignment > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0266451 A1 - Document ID: US20230266451A1 - Status: Published application - Kind: A1 - Application number: 17/676,284 - Filed: 2022-02-21 - Published: 2023-08-24 - Earliest claimed: 2022-02-21 - Assignees: GM Global Technology Operations LLC - Applicants: GM Global Technology Operations LLC - Inventors: Yao HU; Xinyu DU; Wende ZHANG; Hao YU - Web page: https://patentgrep.com/patent/US20230266451A1 ## CPC - G01S 7/4972: {Alignment of sensor} - G01S 7/4802: {using analysis of echo signal for target characterisation; Target signature; Target cross-section} - G01S 7/4808: {Evaluating distance, position or velocity data} - G01S 17/42: Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S17/46) - G01S 17/931: of land vehicles - G01S 17/86: Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES ## Abstract A LIDAR-to-vehicle alignment system includes a sensor data collection module configured to collect points of data provided based on outputs of one or more LIDAR sensors and an alignment module configured to identify lane markings based on the points of data, determine a lane marking direction based on the identified lane markings, calculate a yaw of a LIDAR coordinate system relative to a vehicle coordinate system based on the determined lane marking direction, identify a ground plane based on the points of data, calculate a roll and pitch of the LIDAR coordinate system relative to the vehicle coordinate system based on the identified ground plane, and update a transformation matrix based on the calculated yaw, roll, and pitch of the LIDAR coordinate system. ## Claims ### Claim 1 A LIDAR-to-vehicle alignment system, comprising: a sensor data collection module configured to collect points of data provided based on outputs of one or more LIDAR sensors; and an alignment module configured to identify lane markings based on the points of data, determine a lane marking direction based on the identified lane markings, calculate a yaw of a LIDAR coordinate system relative to a vehicle coordinate system based on the determined lane marking direction, identify a ground plane based on the points of data, calculate a roll and pitch of the LIDAR coordinate system relative to the vehicle coordinate system based on the identified ground plane, and update a transformation matrix based on the calculated yaw, roll, and pitch of the LIDAR coordinate system. ### Claim 2 (depends on 1) The system of claim 1, further comprising an autonomous driving module configured to perform one or more autonomous driving operations based on the transformation matrix. ### Claim 3 (depends on 1) The system of claim 1, wherein the alignment module is configured to determine whether at least one enablement condition is met prior to calculating the yaw, roll, and pitch of the LIDAR coordinate system. ### Claim 4 (depends on 1) The system of claim 1, wherein the alignment module is configured to identify the lane markings based on an intensity threshold. ### Claim 5 (depends on 4) The system of claim 4, wherein the alignment module is configured to dynamically determine the intensity threshold based on intensities of points of data in a predetermined region of interest. ### Claim 6 (depends on 1) The system of claim 1, wherein the alignment module is configured to determine the lane marking direction using principal component analysis. ### Claim 7 (depends on 1) The system of claim 1, wherein the alignment module is configured determine a normal to the ground plane and calculated the roll and the pitch based on the normal to the ground plane. ### Claim 8 (depends on 7) The system of claim 7, wherein the alignment module is configured to determine the normal to the ground plane using principal component analysis. ### Claim 9 (depends on 1) The system of claim 1, wherein the alignment module is configured to identify statistical outliers in the calculated yaw, roll, and pitch and remove the statistical outliers from the update to the transformation matrix. ### Claim 10 A method of performing LIDAR-to-vehicle alignment, the method comprising: collecting points of data provided based on outputs of one or more LIDAR sensors; identifying lane markings based on the points of data; determining a lane marking direction based on the identified lane markings; calculating a yaw of a LIDAR coordinate system relative to a vehicle coordinate system based on the determined lane marking direction; identifying a ground plane based on the points of data; calculating a roll and pitch of the LIDAR coordinate system relative to the vehicle coordinate system based on the identified ground plane; and updating a transformation matrix based on the calculated yaw, roll, and pitch of the LIDAR coordinate system. ### Claim 11 (depends on 10) The method of claim 10, further comprising performing one or more autonomous driving operations based on the transformation matrix. ### Claim 12 (depends on 10) The method of claim 10, further comprising determining whether at least one enablement condition is met prior to calculating the yaw, roll, and pitch of the LIDAR coordinate system. ### Claim 13 (depends on 10) The method of claim 10, further comprising identifying the lane markings based on an intensity threshold. ### Claim 14 (depends on 13) The method of claim 13, further comprising dynamically determining the intensity threshold based on intensities of points of data in a predetermined region of interest. ### Claim 15 (depends on 10) The method of claim 10, further comprising determining the lane marking direction using principal component analysis. ### Claim 16 (depends on 10) The method of claim 10, further comprising determining a normal to the ground plane and calculating the roll and the pitch based on the normal to the ground plane. ### Claim 17 (depends on 16) The method of claim 16, further comprising determining the normal to the ground plane using principal component analysis. ### Claim 18 (depends on 10) The method of claim 10, further comprising identifying statistical outliers in the calculated yaw, roll, and pitch and removing the statistical outliers from the update to the transformation matrix.