# US 10,768,265 B2 · Systems and methods for direction finding using compressive sensing > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,768,265 B2 - Document ID: US10768265B2 - Status: Granted - Kind: B2 - Application number: 15/346,793 - Filed: 2016-11-09 - Published: 2018-05-10 - Granted: 2020-09-08 - Earliest claimed: 2016-11-09 - Assignees: Raytheon Company - Applicants: Raytheon Company - Inventors: Matthew Granato - Web page: https://patentgrep.com/patent/US10768265B2 ## CPC - 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 3/043: {Receivers} - G01S 3/48: the waves arriving at the antennas being continuous or intermittent and the phase difference of signals derived therefrom being measured - G01S 13/42: Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S13/46) - H01Q 21/06: Arrays of individually energised antenna units similarly polarised and spaced apart - 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 - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) ## Abstract A determination of an angle of arrival of radiofrequency (RF) radiation can be made using compressive sensing techniques to inform a receiver portion of a radar system using fewer measurements and samples of the received signal. A method for compressive sensing at an array antenna includes forming a plurality subarrays of array elements from the array antenna such that each subarray includes two or more array elements, capturing data at the plurality of subarrays of array elements, modulating phase properties of the data captured at each of the subarrays, combining the modulated data from each of the plurality of subarrays to form a measurement having phase and magnitude measurements corresponding to the combined modulated data and determining angle of arrival information for the data using the measurement matrix. ## Claims ### Claim 1 A method for compressive sensing at an array antenna, the method comprising: forming a plurality of subarrays of array elements from the array antenna, wherein a count of array elements in any of the plurality of subarrays is based at least in part on a minimum number of samples needed to reconstruct a received signal, the minimum number of samples being determined based on a restricted isometry property of the array antenna and a mutual incoherence of at least one of a dictionary matrix associated with the array antenna and a measurement matrix associated with the array antenna; during any given time period, capturing data at a subset of the plurality of subarrays of array elements using a plurality of receiver channels coupled to the plurality of subarrays; modulating phase properties of the data captured at each of the subarrays to produce modulated data, the modulating being performed by using a plurality of phase shifters coupled to the plurality of receiver channels; combining the modulated data from each of the plurality of subarrays to form a measurement having phase and magnitude measurements corresponding to the combined modulated data using a summing module; and determining angle of arrival information for the data using the measurement. ### Claim 2 (depends on 1) The method of claim 1, further comprising grouping array elements based on a position of a respective array element in the array antenna. to form the plurality of subarrays. ### Claim 3 (depends on 1) The method of claim 1, further comprising randomly grouping array elements to form randomly interspersed subarrays. ### Claim 4 (depends on 1) The method of claim 1, further comprising capturing data at phase centers of two or more array elements for each of the plurality of subarrays at a predetermined time period. ### Claim 5 (depends on 1) The method of claim 1, further comprising modulating the phase properties using a phase drawn from a uniform random distribution. ### Claim 6 (depends on 1) The method of claim 1, further comprising modulating the phase properties of a combination of data from two or more array elements for each of the plurality of subarrays using pseudorandom phase weighting. ### Claim 7 (depends on 1) The method of claim 1, further comprising generating the dictionary matrix, wherein each entry in the dictionary matrix corresponds to at least one array element and a pair of angles from a range of angles corresponding to a field of view of the array antenna. ### Claim 8 (depends on 1) The method of claim 1, further comprising generating the measurement matrix based on the plurality of subarrays, wherein each row in the measurement matrix corresponds to at least one subarray. ### Claim 9 (depends on 1) The method of claim 1, further comprising using the measurement to generate a direction finding signal indicative of a direction of a signal received by at least of the plurality of subarrays. ### Claim 10 (depends on 1) The method of claim 1, wherein determining the angle of arrival information further comprises using at least one of a Mahalanbois distance method or a basis pursuit method. ### Claim 11 A method for compressive sensing at an array antenna, the method comprising: forming a plurality of subarrays of array elements from the array antenna, wherein a count of array elements in any of the plurality of subarrays is based at least in part on a minimum number of samples needed to reconstruct a received signal, the minimum number of samples being determined based on a restricted isometry property of the array antenna and a mutual incoherence of at least one of a dictionary matrix associated with the array antenna and a measurement matrix associated with the array antenna; during any given time period, capturing data using a plurality of receiver channels coupled at a subset of the plurality of subarrays of array elements using a plurality of receiver channels coupled to the plurality of subarrays; performing compressive sensing on the captured data at each of the plurality of subarrays using a compressive sensing circuit; generating a measurement using the captured data from each of the plurality of subarrays using the compressive sensing circuit; and generating a direction finding signal using the measurement and indicative of a direction of a signal received by at least one of the subarrays using the compressive sensing circuit. ### Claim 12 (depends on 11) The method of claim 11, further comprising selecting one or more subarrays from the plurality of subarrays with which to receive data from. ### Claim 13 (depends on 11) The method of claim 11, further comprising selecting randomly interspersed array elements to form the plurality of subarrays. ### Claim 14 (depends on 11) The method of claim 11, further comprising capturing data at phase centers of two or more array elements for each of the plurality of subarrays at a predetermined time period. ### Claim 15 (depends on 11) The method of claim 11, further comprising modulating the phase properties of a combination of data from two or more array elements for each of the plurality of subarrays using pseudorandom phase weighting. ### Claim 16 A system for compressive sensing at an array antenna, the system comprising: a plurality of array elements formed into a plurality of subarrays, wherein a count of array elements in any of the plurality of subarrays is based at least in part on a minimum number of samples needed to reconstruct a received signal, the minimum number of samples being determined based on at least a restricted isometry property of the array antenna and a mutual incoherence of at least one of a dictionary matrix associated with the array antenna and a measurement matrix associated with the array antenna; a plurality of receiver channels coupled to the plurality of subarrays to capture data at a subset the plurality of subarrays during any given time period; a plurality of phase shifters coupled to the plurality of receiver channels, wherein the phase shifters modulate phase properties of the data captured at each of the subarrays to produce modulated data; and a summing module coupled outputs of the plurality of phase shifters, the summing module configured to combine the modulated data from each of the plurality of subarrays and generate a measurement, wherein the measurement includes angle of arrival information for the data. ### Claim 17 (depends on 16) The system of claim 16, wherein each of the plurality of subarrays comprise array elements within a predetermined distance from each other with respect to the array antenna. ### Claim 18 (depends on 16) The system of claim 16, wherein each of the plurality of subarrays comprise randomly interspersed array elements. ### Claim 19 (depends on 16) The system of claim 16, wherein each of the receiver channels is coupled to at least two or more array elements. ### Claim 20 (depends on 16) The system of claim 16, wherein each of the subarrays are coupled to at least one receiver channel and a phase shift module, wherein the phase shift module is configured to generate a pseudorandom phase weight to modulate phase properties of a combination of data from two or more array elements.