# US 2021/0278512 A1 · Ascertainment of range limits for Lidar devices > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0278512 A1 - Document ID: US20210278512A1 - Status: Published application - Kind: A1 - Application number: 17/193,203 - Filed: 2021-03-05 - Published: 2021-09-09 - Earliest claimed: 2020-03-05 - Applicants: Robert Bosch GmbH - Inventors: Chengxuan Fu; Gabriela Samagaio; Ricardo Martins Costa - Web page: https://patentgrep.com/patent/US20210278512A1 ## CPC - G01S 7/497: Means for monitoring or calibrating - G01S 17/931: of land 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 method for ascertaining a range limit of a LIDAR device, due to environmental influences, by use of a control unit is provided. For ascertaining distances between the LIDAR device and at least one surface in a scanning area, beams are emitted into the scanning area by a transmitting unit of the LIDAR device, and beams that are reflected and/or backscattered from the scanning area are received by a receiving unit of the LIDAR device. The distances between the LIDAR device and the surface are computed based on the propagation times of the transmitted beams and of the reflected and/or backscattered beams. A range limit of a maximum possible range of the LIDAR device is ascertained based on a variance of the computed distances. Moreover, a control unit and a LIDAR device are provided. ## Claims ### Claim at position 1 1-11. (canceled) ### Claim 12 A method for ascertaining a range limit of a LIDAR device, due to environmental influences, by a control unit, for ascertaining distances between the LIDAR device and at least one surface in a scanning area, the method comprising the following steps: emitting beams into the scanning area by a transmitting unit of the LIDAR device; receiving beams that are reflected and/or backscattered from the scanning area by a receiving unit of the LIDAR device computing the distances between the LIDAR device and the surface based on propagation times of the transmitted beams and of the reflected and/or backscattered beams; and ascertaining a range limit of a maximum possible range of the LIDAR device based on a variance of the computed distances. ### Claim 13 (depends on 12) The method as recited in claim 12, wherein the range limit of the LIDAR device is ascertained inversely proportional to the maximum possible range of the LIDAR device. ### Claim 14 (depends on 12) The method as recited in claim 12, wherein an increasing range limit of the LIDAR device is computed at an increasing variance, a smaller maximum possible range of the LIDAR device being deduced from the increasing range limit of the LIDAR device. ### Claim 15 (depends on 12) The method as recited in claim 12, wherein a smaller range limit of the LIDAR device is computed at a decreasing variance, a larger maximum possible range of the LIDAR device being ascertained from the smaller range limit of the LIDAR device. ### Claim 16 (depends on 12) The method as recited in claim 12, wherein the variance of the computed distances is computed from temporally smoothed distances. ### Claim 17 (depends on 12) The method as recited in claim 12, wherein the propagation times of the beams and/or the distances between the LIDAR device and the surface that are computed from the propagation times are used from measurements within an intensity range for computing the variance. ### Claim 18 (depends on 17) The method as recited in claim 17, wherein the range limit is classified based on value ranges of the computed variance. ### Claim 19 (depends on 18) The method as recited in claim 18, wherein the range limit in a value range of the variance of the distances between 140 m2 and 180 m2 is classified as “strong,” in a value range of the variance of the distances between 120 m2 and 140 m2 is classified as “medium,” in a value range of the variance of the distances between 40 m2 and 120 m2 is classified as “low,” and in a value range of the variance of the distances between 0 m2 and 40 m2 is classified as “not present.” ### Claim 20 (depends on 12) The method as recited in claim 12, wherein control commands for adapting a driving function are generated based on the ascertained range limit. ### Claim 21 A control unit configured to ascertain a range limit of a LIDAR device, due to environmental influences, for ascertaining distances between the LIDAR device and at least one surface in a scanning area, the control unit configured to: emit beams into the scanning area by a transmitting unit of the LIDAR device; receive beams that are reflected and/or backscattered from the scanning area by a receiving unit of the LIDAR device; compute the distances between the LIDAR device and the surface based on propagation times of the transmitted beams and of the reflected and/or backscattered beams; and ascertain a range limit of a maximum possible range of the LIDAR device based on a variance of the computed distances. ### Claim 22 A LIDAR device for scanning a scanning area, comprising: a transmitting unit with at least one beam source configured to generate and emit beams into the scanning area; a receiving unit configured to receive and detect beams that are reflected and/or backscattered from the scanning area; and a control unit configured to ascertain a range limit of the LIDAR device, due to environmental influences, for ascertaining distances between the LIDAR device and at least one surface in a scanning area, the control unit configured to: emit beams into the scanning area using the transmitting unit, receive beams that are reflected and/or backscattered from the scanning area using the receiving unit, compute the distances between the LIDAR device and the surface based on propagation times of the transmitted beams and of the reflected and/or backscattered beams, and ascertain a range limit of a maximum possible range of the LIDAR device based on a variance of the computed distances.