# US 10,481,249 B2 · Radar apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,481,249 B2 - Document ID: US10481249B2 - Status: Granted - Kind: B2 - Application number: 15/322,856 - Filed: 2015-07-01 - Published: 2017-05-18 - Granted: 2019-11-19 - Earliest claimed: 2014-07-04 - Assignees: Denso Corporation - Applicants: Denso Corporation - Inventors: Klas Alenljung; Yoshihiro Abe - Web page: https://patentgrep.com/patent/US10481249B2 ## CPC - G01S 13/4454: {phase comparisons monopulse, i.e. comparing the echo signals received by an interferometric antenna arrangement} - G01S 7/2921: {based on data belonging to one radar period} - G01S 7/354: {Extracting wanted echo-signals (Doppler systems G01S13/50)} - 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 13/42: Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S13/46) - G01S 13/931: of land vehicles - G01S 3/74: Multi-channel systems specially adapted for direction-finding, i.e. having a single antenna system capable of giving simultaneous indications of the directions of different signals (systems in which the directions of different signals are determined sequentially and displayed simultaneously G01S3/04, G01S3/14) - G01S 2013/93185: {Controlling the brakes} - 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 radar apparatus includes: a transmitting portion including transmitter elements that emits a transmitting signal as a radar wave toward an object; a receiving portion including receiver elements receiving a reflection signal; and an estimation portion. The estimation portion generates a virtual receiving array including virtual receiver elements. The estimation portion divides the virtual receiving array into identical sub-arrays. The estimation portion generates covariance matrix data for each of the sub-arrays. The estimation portion averages the covariance matrix data for each of the sub-arrays to decorrelate a direct reflection signal from the object and multipath reflection signal among the reflection signal and spatially smooths the reflection signal. The estimation portion resolves the direct reflection signal from the object and the multipath reflection signal. The estimation portion determines the direction of the object. ## Claims ### Claim 1 A radar apparatus comprising: a transmitting portion including a plurality of transmitter elements that emits a transmitting signal as a radar wave toward an object; a receiving portion including a plurality of receiver elements receiving a reflection signal that is a reflection of the transmitting signal by the object; and an estimation portion, wherein: the estimation portion generates a virtual receiving array including virtual receiver elements whose number corresponds to a total number of receiver elements multiplied by a total number of transmitter elements; the estimation portion divides the virtual receiving array into a plurality of identical sub-arrays; the estimation portion generates covariance matrix data for each of the sub-arrays based on the reflection signal; the estimation portion averages the covariance matrix data for each of the sub-arrays to decorrelate a direct reflection signal from the object and multipath reflection signal among the reflection signal and spatially smooths the reflection signal; the estimation portion resolves the direct reflection signal from the object and the multipath reflection signal based on the result of spatial smoothing of the reflection signal; and the estimation portion determines the direction of the object based on the direct reflection signal. ### Claim 2 (depends on 1) The radar apparatus according to claim 1, wherein: the transmitting portion includes at least two transmitter elements; the receiving portion includes at least three receiver elements that are arranged in at least two rows in a first direction and at least three columns in a second direction perpendicular to the first direction; and a first respective distance in the first direction between neighboring ones of all of the at least two transmitter elements corresponds to a second respective distance in the first direction between neighboring ones of all receiver elements in neighboring rows multiplied by a total number of rows of receiver elements. ### Claim 3 (depends on 2) The radar apparatus according to claim 2, wherein: in a case of an odd number of receiver elements, the transmitter elements are provided in an identical column. ### Claim 4 (depends on 2) The radar apparatus according to claim 2, wherein: in a case of an even number of receiver elements, a third respective distance in the second direction between neighboring ones of all of the at least two transmitter elements in neighboring rows corresponds to a fourth respective distance in the second direction between neighboring receiver elements in different rows multiplied by the number of rows of receiver elements. ### Claim 5 (depends on 2) The radar apparatus according to claim 2, wherein: in the virtual receiving array, a total number of virtual receiver elements is doubled in the first direction in comparison to the number of receiver elements in a receiving antenna in the first direction. ### Claim 6 (depends on 1) The radar apparatus according to claim 1, wherein: the transmitting antenna includes at least two transmitter elements; a receiving antenna includes at least two groups of receiver elements wherein each group has at least two receiver elements that are arranged in at least two rows in a first direction and at least two columns in a second direction perpendicular to the first direction; a first respective distance in the second direction between neighboring ones of all of the at least two transmitter elements in an identical same row corresponds to a twofold of a second respective distance in the second direction between neighboring ones of all receiver elements in one group; and a third respective distance in the second direction in an identical row between structurally corresponding receiver elements of neighboring groups of receiver elements corresponds to the first respective distance in the second direction between neighboring ones of all of the at least two transmitter elements in the identical row multiplied by the number of transmitter elements in one row. ### Claim 7 (depends on 6) The radar apparatus according to claim 6, wherein: in the virtual receiving array, a total number of virtual receiver elements is doubled in the second direction in comparison to the number of receiver elements in the receiving antenna in the second direction. ### Claim 8 (depends on 1) The radar apparatus according to claim 1, wherein: the transmitter elements and the receiver elements are disposed in an identical plane and the first direction is a vertical direction and a second direction is a horizontal direction. ### Claim 9 (depends on 1) The radar apparatus according to claim 1, wherein: the estimation portion applies an eigenstructure technique to each of the covariance matrix data of the virtual receiving array. ### Claim 10 (depends on 9) The radar apparatus according to according to claim 9, wherein: the eigenstructure technique is a multiple signal classification algorithm.