# US 2021/0239796 A1 · Method and device for determining a radar cross section, method for training an interaction model, and radar target emulator and test facility > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0239796 A1 - Document ID: US20210239796A1 - Status: Published application - Kind: A1 - Application number: 17/046,955 - Filed: 2019-04-12 - Published: 2021-08-05 - Earliest claimed: 2018-04-13 - Assignees: AVL List GmbH - Applicants: Avl List GmbH - Inventors: Franz Michael MAIER; Vamsi Prakash MAKKAPATI - Web page: https://patentgrep.com/patent/US20210239796A1 ## CPC - G01S 7/021: {Auxiliary means for detecting or identifying radar signals or the like, e.g. radar jamming signals} - G01S 7/4078: {involving an integrated reference reflector or reference transponder} - G01S 7/40: Means for monitoring or calibrating - G01S 7/4052: {by simulation of echoes} - G01S 7/4069: {involving a RF signal injection} - G01S 7/41: using analysis of echo signal for target characterisation; Target signature; Target cross-section - G01S 7/412: {based on a comparison between measured values and known or stored values} - G01S 13/42: Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S13/46) - G01S 13/931: 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 and a device for determining a radar cross section, a method for training an interaction model, a radar target emulator for manipulating a radar signal, and a test facility for a vehicle are described herein. The propagation of a virtual radar signal is simulated on the basis of an interaction model in a simulated environment scenario that contains the simulated radar target. An interaction of the virtual radar signal with the simulated radar target is modelled such that a physical variable, characterizing the virtual radar signal, is divided into a directional component that corresponds to a directed scattering of the virtual radar signal and into a diffuse component that corresponds to an isotropic scattering of the virtual radar signal. A value of the physical variable is determined at a receiver point in the simulated environment scenario, taking into account the directional component and the diffuse component, and the radar cross section of the simulated radar target is derived from the determined value of the physical variable at the receiver point. ## Claims ### Claim 1 A method for determining a radar cross section of a simulated radar target comprising the procedural steps: Simulating the propagation of a virtual radar on the basis of an interaction model in a simulated environment scenario which contains the simulated radar target, wherein an interaction of the virtual radar signal with the simulated radar target is modeled such that a physical variable characterizing the virtual radar signal is divided into a directional component corresponding to a directed scattering of the virtual radar signal and a diffuse component corresponding to an isotropic scattering of the virtual radar signal, wherein the propagation of the directional component is simulated in a sub-step and the interaction of the directional component with a further simulated radar target is calculated in a subsequence sub-step; Determining a value of the physical variable at a receiver point in the simulated environment scenario factoring in the directional component and the diffuse component; and Deriving the radar cross section of the simulated radar target from the determined value of the physical variable at the receiver point. ### Claim 2 (depends on 1) The method according to claim 1, wherein the propagation of the virtual radar signal from a transmitter point in the environment scenario to the simulated radar target is simulated on the basis of an analytic description of the propagation of radar signals. ### Claim 3 (depends on 1) The method according to claim 1, wherein the virtual radar signal contains a plurality of partial signals and the interaction of the virtual radar signal with the simulated radar target is modeled for each of the partial signals, and the radar cross section derived on the basis of a plurality of determined values of the physical variable at the receiver point. ### Claim 4 (depends on 1) The method according to claim 1, wherein the physical variable is divided into the directional component and the diffuse component as a function of at least one model parameter characterizing a physical property of the simulated radar target. ### Claim 5 (depends on 1) The method according to claim 1 using the Phong formula. ### Claim 6 (canceled) ### Claim 7 A method for training an interaction model, by means of which an interaction of a virtual radar signal with a simulated radar target can be modeled such that a physical variable characterizing the virtual radar signal is divided into a directional component corresponding to a directed scattering of the virtual radar signal and a diffuse component corresponding to an isotropic scattering of the virtual radar signal, comprising the procedural steps: Simulating the interaction of a virtual radar signal with a reference target on the basis of an analytic description of the reflection of the radar signal at the reference target, wherein at least one value of a physical variable which characterizes the virtual radar signal reflected at the reference target is determined, or Modeling the interaction of a real radar signal with a real emulation of the reference target, wherein at least one value of the physical variable which characterizes the real radar signal reflected on the real emulation of the reference target is measured; and Determining at least one model parameter the interaction model on the basis of the at least one determined value of the physical variable. ### Claim 8 (depends on 7) The method according to claim 7, wherein the at least one model parameter is determined on the basis of a curve fitting. ### Claim 9 (depends on 7) The method according to claim 7, wherein the reference target is a sphere. ### Claim 10 (depends on 7) The method according to claim 7, wherein the propagation of the virtual or real radar signal is simulated or modeled for multiple different reference objects, at least one model parameter is in each case determined on the basis of the values of the physical variable thereby determined, and the determined model parameters are stored as a function of object properties of the multiple different reference objects. ### Claim 11 (depends on 1) A device for determining a radar cross section of a simulated radar target which is configured to realize a method according to claim 1. ### Claim 12 (depends on 11) A radar target emulator for manipulating a real radar signal output by a vehicle, comprising: a simulation device which is configured to simulate an environment scenario and output simulation data characterizing the environment scenario; a device for determining a radar cross section of a simulated radar target according to claim 11 that is configured to output at least one stimulation point on the basis of the simulation data; a stimulation device configured to record, the real radar signal, manipulate the real radar signal on the basis of the at least one stimulation point, and output the thusly manipulated radar signal. ### Claim 13 (depends on 12) A test facility for a vehicle, comprising a radar target emulator according to claim 12. ### Claim 14 (depends on 1) The method according to claim 1, wherein the sub-step and the subsequent sub-step are repeated until none of the directional components encounter a further radar signal.