# US 12,007,498 B2 · Signal processing for near-field radar > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,007,498 B2 - Document ID: US12007498B2 - Status: Granted - Kind: B2 - Application number: 16/952,328 - Filed: 2020-11-19 - Published: 2021-03-18 - Granted: 2024-06-11 - Earliest claimed: 2017-12-29 - Assignees: Waymo LLC - Applicants: Waymo LLC - Inventors: Timothy Campbell; Brett Coon - Web page: https://patentgrep.com/patent/US12007498B2 ## CPC - G01S 7/2923: {based on data belonging to a number of consecutive radar periods} - G01S 7/0231: {Avoidance by polarisation multiplex} - G01S 7/354: {Extracting wanted echo-signals (Doppler systems G01S13/50)} - G01S 13/343: {using sawtooth modulation} - G01S 13/42: Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S13/46) - G01S 13/931: of land vehicles - G01S 7/032: {Constructional details for solid-state radar subsystems} - G01S 7/4021: {of receivers} - G01S 13/90: using synthetic aperture techniques {, e.g. synthetic aperture radar [SAR] techniques} - 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 Examples relate to near-field radar filters that can enhance measurements near a radar unit. An example may involve receiving a first set of radar reflection signals at a radar unit coupled to a vehicle and determining a filter configured to offset near-field effects of radar reflection signals received at the radar unit. In some instances, the filter depends on an azimuth angle and a distance for surfaces in the environment causing the first set of radar reflection signals. The example may also involve receiving, at the radar unit, a second set of radar reflection signals and determining, using the filter, an azimuth angle and a distance for surfaces in the environment causing the second set of radar reflection signals. The vehicle may be controlled based in part on the azimuth angle and the distance for the surfaces causing the second plurality of radar reflection signals. ## Claims ### Claim 1 A method comprising: transmitting, by a radar unit coupled to a vehicle, a plurality of radar signals into an environment of the vehicle as the vehicle navigates a path in the environment; receiving, at the radar unit, a plurality of radar reflection signals corresponding to the plurality of radar signals; detecting, based on the plurality of radar reflection signals, a degree of curvature of radar reflection signals corresponding to near-field measurements of the environment; based on detecting the degree of curvature of the radar reflection signals corresponding to near-field measurements, generating, by a computing system coupled to the vehicle, a filter configured to offset near-field effects of radar reflection signals received at the radar unit as the vehicle navigates the path in the environment, wherein one or more parameters of the filter compensate for the degree of curvature of the radar reflections corresponding to near-field measurements and depends on an azimuth angle and a distance for one or more surfaces in the environment that caused the radar reflection signals corresponding to near-field measurements; and storing the filter in memory prior to powering off the radar unit, wherein the computing system is configured to access the filter in memory and subsequently use the filter to process near-field measurements of radar reflection signals received by the radar unit. ### Claim 2 (depends on 1) The method of claim 1, further comprising: receiving, at the radar unit, a second plurality of radar reflection signals; and detecting, using the filter, one or more objects in the environment. ### Claim 3 (depends on 2) The method of claim 2, wherein detecting the one or more objects in the environment further comprises: determining, using the filter, an azimuth angle and a distance for one or more objects in the environment. ### Claim 4 (depends on 3) The method of claim 3, further comprising: controlling the vehicle based at least in part on the azimuth angle and the distance for the one or more objects in the environment. ### Claim 5 (depends on 1) The method of claim 1, wherein receiving the plurality of radar reflection signals comprises: receiving the plurality of radar reflection signals using an antenna array of the radar unit. ### Claim 6 (depends on 1) The method of claim 1, wherein the one or more surfaces that caused the plurality of radar reflection signals correspond to an object positioned in a near-field of the radar unit, and wherein the near-field of the radar unit is within 20 meters of the radar unit. ### Claim 7 (depends on 1) The method of claim 1, wherein generating the filter configured to offset near-field effects of radar reflection signals received at the radar unit comprises: generating the filter as a quadratic matched filter. ### Claim 8 (depends on 1) The method of claim 1, wherein generating the filter configured to offset near-field effects of radar reflection signals received at the radar unit comprises: generating the filter based on an apodized filter. ### Claim 9 (depends on 1) The method of claim 1, wherein transmitting the plurality of radar signals comprises: transmitting linear frequency modulated radar signals. ### Claim 10 (depends on 1) The method of claim 1, wherein generating the filter configured to offset near-field effects of radar reflection signals received at the radar unit further comprises: generating the filter further based on a position and orientation of an antenna array used by the radar. ### Claim 11 (depends on 10) The method of claim 10, wherein generating the filter further based on the position and orientation of the antenna array used by the radar comprises: generating the filter further based on respective spacing between antenna elements in the antenna array used by the radar. ### Claim 12 A radar system comprising: a radar unit coupled to a vehicle and configured to: transmit a plurality of radar signals into an environment of the vehicle as the vehicle navigates a path in the environment; and receive a plurality of radar reflection signals corresponding to the plurality of radar signals; and a computing device coupled to the vehicle and configured to: detect, based on the plurality of radar reflection signals, a degree of curvature of radar reflection signals corresponding to near-field measurements of the environment; based on detecting the degree of curvature of the radar reflection signals corresponding to near-field measurements, generate a filter configured to offset near-field effects of radar reflection signals received at the radar unit as the vehicle navigates the path in the environment, wherein one or more parameters of the filter compensate for the degree of curvature of the radar reflections corresponding to near-field measurements and depends on an azimuth angle and a distance for one or more surfaces in the environment that caused the radar reflection signals corresponding to near-field measurements; and store the filter in memory prior to powering off the radar unit, wherein the computing device is configured to access the filter in memory and subsequently user the filter to process near-field measurements of radar reflection signals received by the radar unit. ### Claim 13 (depends on 12) The radar system of claim 12, wherein the vehicle includes a plurality of radar units configured to operate over a 360-degree azimuth plane around the vehicle. ### Claim 14 (depends on 12) The radar system of claim 12, wherein the computing device is further configured to generate the filter based on a quadratic matched filter. ### Claim 15 (depends on 12) The radar system of claim 12, wherein the computing device is further configured to generate the filter based on an apodized filter. ### Claim 16 A non-transitory computer-readable medium configured to store instructions, that when executed by a computing system comprising one or more processors, causes the computing system to perform operations comprising: causing a radar unit to transmit a plurality of radar signals into an environment of a vehicle as the vehicle navigates a path in the environment; obtaining, from the radar unit, a plurality of radar reflection signals corresponding to the plurality of radar signals; detecting, based on the plurality of radar reflection signals, a degree of curvature of radar reflection signals corresponding to near-field measurements of the environment; based on detecting the degree of curvature of the radar reflection signals corresponding to near-field measurements, generating a filter configured to offset near-field effects of radar reflection signals received at the radar unit as the vehicle navigates the path in the environment, wherein one or more parameters of the filter compensate for the degree of curvature of the radar reflections corresponding to near-field measurements and depends on an azimuth angle and a distance for one or more surfaces in the environment that caused the plurality of radar reflection signals; storing the filter in memory prior to powering off the radar unit, wherein the computing system is configured to access the filter in memory and subsequently use the filter to process near-field measurements of radar reflection signals received by the radar unit. ### Claim 17 (depends on 16) The non-transitory computer-readable medium of claim 16, further comprising: obtaining, from the radar unit, a second plurality of radar reflection signals; and detecting, using the filter, one or more objects in the environment. ### Claim 18 (depends on 17) The non-transitory computer-readable medium of claim 17, wherein detecting the one or more objects in the environment further comprises: determining, using the filter, an azimuth angle and a distance for one or more objects in the environment. ### Claim 19 (depends on 18) The non-transitory computer-readable medium of claim 18, further comprising: controlling the vehicle based at least in part on the azimuth angle and the distance for the one or more objects in the environment, wherein the radar unit is coupled to the vehicle. ### Claim 20 (depends on 16) The non-transitory computer-readable medium of claim 16, further comprising: obtaining, from the radar unit, a subsequent plurality of radar reflection signals; and updating the filter based on the subsequent plurality of radar reflection signals.