# US 2014/0191899 A1 · Systems and methods for tracking targets by a through-the-wall radar using multiple hypothesis tracking > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0191899 A1 - Document ID: US20140191899A1 - Status: Published application - Kind: A1 - Application number: 13/523,747 - Filed: 2012-06-14 - Published: 2014-07-10 - Earliest claimed: 2012-06-14 - Assignees: Raytheon Company - Inventors: Catherine Pickle; Samuel S. Blackman; Douglas B. Tyler - Web page: https://patentgrep.com/patent/US20140191899A1 ## CPC - G01S 13/66: Radar-tracking systems; Analogous systems - G01S 7/41: using analysis of echo signal for target characterisation; Target signature; Target cross-section - G01S 13/726: {Multiple target tracking} - G01S 13/888: {through wall detection} - G01S 2013/462: {using multipath signals} - 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 Aspects of the present invention relate to a system (10) and a method for tracking one or more targets by a radar using a multiple hypothesis tracking (MHT) algorithm, the method including operating the radar to transmit a radar beam from a first location toward the one or more targets, operating the radar to receive a plurality of return signals at the first location from the one or more targets, and to generate a plurality of observations for a single radar dwell respectively corresponding to the plurality of return signals, and processing the plurality of observations in accordance with the MHT algorithm for at least two passes such that more than one of the plurality of observations are associated with a single track of the one or more targets. ## Claims ### Claim 1 A method for tracking one or more targets by a radar using a multiple hypothesis tracking (MHT) algorithm, the method comprising: operating the radar to transmit a radar beam from a first location toward the one or more targets; operating the radar to receive a plurality of return signals at the first location from the one or more targets, and to generate a plurality of observations for a single radar dwell respectively corresponding to the plurality of return signals; and processing the plurality of observations in accordance with the MHT algorithm for at least two passes such that more than one of the plurality of observations are associated with a single track of the one or more targets. ### Claim 2 (depends on 1) The method of claim 1, wherein the at least two passes comprise a first pass and at least one second pass, and the processing the plurality of observations comprises: processing the plurality of observations in the first pass while assuming all of the observations to be associated with direct path return signals from the one or more targets; and processing the plurality of observations in the at least one second pass while assuming all of the observations to be associated with multipath return signals from the one or more targets. ### Claim 3 (depends on 2) The method of claim 2, wherein in the first pass, the processing the plurality of observations comprise initiating one or more potential first tracks in accordance with the plurality of observations, wherein each track of the one or more potential first tracks is associated with at most one of the plurality of observations. ### Claim 4 (depends on 3) The method of claim 3, wherein in the first pass, the processing the plurality of observations further comprises performing track filtering to update one or more potential existing tracks in accordance with the plurality of observations. ### Claim 5 (depends on 3) The method of claim 3, wherein the one or more targets are presumed to be located in a preselected area, and a track of the one or more potential first tracks corresponding to a position outside of the preselected area is not updated in the at least one second pass. ### Claim 6 (depends on 2) The method of claim 2, wherein the processing the plurality of observations comprises propagating existing tracks to current time in the first pass. ### Claim 7 (depends on 2) The method of claim 2, wherein the processing the plurality of observations comprises one or more of converting observations, propagating existing tracks, initiating new tracks, and filtering racks, only in the first pass. ### Claim 8 (depends on 2) The method of claim 2, wherein the at least one second pass comprises a plurality of second passes, and the plurality of observations are processed under a different preselected multipath scenario for each of the plurality of second passes. ### Claim 9 (depends on 1) The method of claim 1, wherein the processing the plurality of observations comprises one or more of gating, track scoring, track limiting, track coasting, branch track formation, and clusters merging, in each of the at least two passes. ### Claim 10 (depends on 1) The method of claim 1, wherein the processing the plurality of observations comprises one or more of maintaining track incompatibility list, limiting tracks in clusters, forming track hypotheses, identifying primary tracks, pruning tracks, updating universal tracks, and reclustering tracks, in a last one of the at least two passes. ### Claim 11 A radar system comprising: a transmitter configured to transmit a radar beam from a first location toward one or more targets; a receiver configured to receive a plurality of return signals at the first location from the one or more targets; and a processor configured to generate a plurality of observations for a single radar dwell respectively corresponding to the plurality of return signals and to process the plurality of observations in accordance with a multiple hypothesis tracking (MHT) algorithm for at least two passes such that more than one of the plurality of observations are associated with a single track of the one or more targets. ### Claim 12 (depends on 11) The radar system of claim 11, wherein the at least two passes comprise a first pass and at least one second pass, and wherein the processor is configured to process the plurality of observations in the first pass while assuming all of the observations to be associated with direct path return signals from the one or more targets, and to process the plurality of observations in the at least one second pass while assuming all of the observations to be associated with multipath return signals from the one or more targets. ### Claim 13 (depends on 12) The radar system of claim 12, wherein the processor is further configured to initiate one or more potential first tracks in accordance with the plurality of observations in the first pass, and wherein each track of the one or more potential first tracks is associated with at most one of the plurality of observations. ### Claim 14 (depends on 13) The radar system of claim 13, wherein the processor is further configured to perform track-filtering to update one or more potential existing tracks in accordance with the plurality of observations in the first pass. ### Claim 15 (depends on 13) The radar system of claim 13, wherein the processor is configured to presume the one or more targets to be located in a preselected area, and a track of the one or more potential first tracks corresponding to a position outside of the preselected area is not updated in the at least one second pass. ### Claim 16 (depends on 12) The radar system of claim 12, wherein the processor is further configured to propagate existing tracks to current time in the first pass. ### Claim 17 (depends on 12) The radar system of claim 12, wherein the processor is further configured to perform one or more of converting observations, propagating existing tracks, initiating new tracks, and filtering tracks, only in the first pass. ### Claim 18 (depends on 12) The radar system of claim 12, wherein the at least one second pass comprises a plurality of second passes, and the processor is configured to process the plurality of observations under a different preselected multipath in each of the plurality of second passes. ### Claim 19 (depends on 11) The radar system of claim 11, wherein the processor is further configured to perform one or more of gating, track scoring, track limiting, track coasting, branch track formation, and cluster merging, in each of the at least two passes. ### Claim 20 (depends on 11) The radar system of claim 11, wherein the processor is further configured to perform one or more of track incompatibility list maintenance, track cluster limiting, track hypotheses formation, primary tracks identification, tracks pruning, updating universal tracks, and track reclustering, in a last one of the at least two passes.