# US 2021/0278511 A1 · Radar calibration > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0278511 A1 - Document ID: US20210278511A1 - Status: Published application - Kind: A1 - Application number: 16/807,608 - Filed: 2020-03-03 - Published: 2021-09-09 - Earliest claimed: 2020-03-03 - Assignees: Ford Global Technologies, LLC - Applicants: Ford Global Technologies, LLC - Inventors: Krishanth Krishnan; Sangjin Lee; Ankit Girish Vora; Siddharth Agarwal - Web page: https://patentgrep.com/patent/US20210278511A1 ## CPC - G01S 7/4026: {Antenna boresight} - G01S 7/497: Means for monitoring or calibrating - G01S 7/4004: {of parts of a radar system} - G01S 7/4082: {using externally generated reference signals, e.g. via remote reflector or transponder} - G01S 13/34: using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal - G01S 13/86: Combinations of radar systems with non-radar systems, e.g. sonar, direction finder - G01S 13/865: {Combination of radar systems with lidar systems} - G01S 13/931: of land vehicles - G01S 2013/932: {using own vehicle data, e.g. ground speed, steering wheel direction} - G01S 2013/93271: {in the front of the vehicles} - 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 calibration system for a radar sensor and a method of using the system are disclosed. The method may comprise (a) (a) receiving, from a first sensor in a vehicle, a plurality of global navigation satellite system (GNSS) parameters, wherein the plurality of GNSS parameters define a unique terrestrial position of the first sensor; (b) receiving, from a radar sensor in the vehicle, a plurality of radar parameters, wherein the plurality of radar parameters define a position of a calibration target relative to the radar sensor; (c) repeating the receiving of (a) and (b) at additional unique terrestrial positions of the first sensor; (d) using the plurality of GNSS parameters received in (a) and (c) and the plurality of radar parameters received in (b) and (c), determining corresponding positions of the calibration target; and (e) using the corresponding positions of the calibration target, determining radar calibration parameters. ## Claims ### Claim 1 A method, comprising: (a) receiving, from a first sensor in a vehicle, a plurality of global navigation satellite system (GNSS) parameters, wherein the plurality of GNSS parameters define a unique terrestrial position of the first sensor; (b) receiving, from a radar sensor in the vehicle, a plurality of radar parameters, wherein the plurality of radar parameters define a position of a calibration target relative to the radar sensor; (c) repeating the receiving of (a) and (b) at additional unique terrestrial positions of the first sensor; (d) using the plurality of GNSS parameters received in (a) and (c) and the plurality of radar parameters received in (b) and (c), determining corresponding positions of the calibration target; and (e) using the corresponding positions of the calibration target, determining radar calibration parameters. ### Claim 2 (depends on 1) The method of claim 1, wherein (a), (b), and (c) are repeated to receive a threshold quantity of unique terrestrial positions. ### Claim 3 (depends on 1) The method of claim 1, wherein (e) further comprises: determining the radar calibration parameters using a first transformation matrix relative to a frame of reference of the first sensor and using a second transformation matrix relative to a frame of reference of the second sensor. ### Claim 4 (depends on 3) The method of claim 3, wherein at least one of the first or second transformation matrices is a rotation matrix. ### Claim 5 (depends on 4) The method of claim 4, wherein (e) further comprises: determining a plurality of Euclidean differences using the corresponding positions of the calibration target. ### Claim 6 (depends on 5) The method of claim 5, wherein (e) further comprises: determining a summation of the plurality of Euclidean differences; and determining the radar calibration parameters using an optimization function that determines a set of radar calibration parameters that minimize the summation. ### Claim 7 (depends on 6) The method of claim 6, wherein the set of radar calibration parameters comprise either: an x-parameter, a y-parameter, and a yaw-parameter. ### Claim 8 (depends on 6) The method of claim 6, further comprising: determining an upper bound or a lower bound of each of the radar calibration parameters. ### Claim 9 (depends on 1) The method of claim 1, further comprising: programming a computer or the radar sensor with the radar calibration parameters. ### Claim 10 (depends on 1) The method of claim 1, wherein the calibration target is fixed during (b) and (c). ### Claim 11 (depends on 1) The method of claim 1, wherein the first sensor is within a threshold distance of the calibration target during (b) and (c). ### Claim 12 (depends on 1) The method of claim 1, wherein the radar sensor is a two-dimensional (2D) radar sensor or a three-dimensional (3D) radar sensor, wherein the first sensor is one of a Global Positioning System (GPS) device or a Global Navigation Satellite System (GLONASS) device. ### Claim 13 (depends on 1) The method of claim 1, wherein the calibration target is a corner reflector. ### Claim 14 A calibration system for a radar sensor in a vehicle, comprising: a first sensor in the vehicle; a calibration target; and a computer, comprising one or more processors and memory storing instructions executable by the one or more processors, the instructions comprising to: (a) receive, from a first sensor in the vehicle, a plurality of global navigation satellite system (GNSS) parameters, wherein the plurality of GNSS parameters define a unique terrestrial position of the first sensor; (b) receive, from the radar sensor in the vehicle, a plurality of radar parameters, wherein the plurality of radar parameters define a position of a calibration target relative to the radar sensor; (c) repeat the receiving of (a) and (b) at additional unique terrestrial positions of the first sensor; (d) using the plurality of GNSS parameters received in (a) and (c) and the plurality of radar parameters received in (b) and (c), determine corresponding positions of the calibration target; and (e) using the corresponding positions of the calibration target, determine radar calibration parameters. ### Claim 15 (depends on 14) The system of claim 14, wherein (e) further comprises to: determine the radar calibration parameters using a first transformation matrix relative to a frame of reference of the first sensor and using a second transformation matrix relative to a frame of reference of the second sensor. ### Claim 16 (depends on 15) The system of claim 15, wherein (e) further comprises to: determine a plurality of Euclidean differences using the corresponding positions of the calibration target. ### Claim 17 (depends on 16) The system of claim 16, wherein (e) further comprises to: determine a summation of the plurality of Euclidean differences; and determine the radar calibration parameters using an optimization function that determines a set of radar calibration parameters that minimize the summation. ### Claim 18 (depends on 17) The system of claim 17, wherein the set of radar calibration parameters comprise either: an x-parameter, a y-parameter, and a yaw-parameter. ### Claim 19 (depends on 14) The system of claim 14, wherein the instructions further comprise to: program a computer or the radar sensor with the radar calibration parameters. ### Claim 20 (depends on 14) The system of claim 14, wherein the calibration target is fixed during (b) and (c).