# US 12,007,271 B2 · Vibrometry and sound reproduction of acoustic sources on moving platforms using radar > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,007,271 B2 - Document ID: US12007271B2 - Status: Granted - Kind: B2 - Application number: 17/406,040 - Filed: 2021-08-18 - Published: 2022-11-17 - Granted: 2024-06-11 - Earliest claimed: 2020-08-18 - Assignees: The Government of the United States of America, as represented by the Secretary of the Navy - Applicants: The Government of the United States of America, as represented by the Secretary of the Navy - Inventors: Christopher T. Rodenbeck; Joshua B. Beun; Ronald D. Lipps; Raghu G. Raj - Web page: https://patentgrep.com/patent/US12007271B2 ## CPC - G01H 9/00: Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means - G01S 13/9019: {Auto-focussing of the SAR signals} - G01S 7/415: {Identification of targets based on measurements of movement associated with the target} - G01S 13/9029: {specially adapted for moving target detection within a single SAR image or within multiple SAR images taken at the same time} - G01S 13/582: {adapted for simultaneous range and velocity measurements} - G01S 13/89: for mapping or imaging - G01H: MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES - 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 Systems and methods are provided for interrogating a moving acoustic source using radar and processing data using a selection of motion compensation techniques adapted from synthetic aperture radar (SAR) to remove the effects of linear and nonlinear target motion so that the range-Doppler map retains only vibration information in the Doppler dimension. Vibration and sound waveforms can thus be selectively reproduced at specific ranges directly from the radar baseband waveform, without the need for additional complex analysis or audio processing. ## Claims ### Claim 1 A radar system, comprising: a radar configured to: send a signal towards a moving object, and receive a return signal; and a motion compensator configured to: receive the return signal from the radar, determine a direct estimate for a velocity of the object based on the return signal, determine an indirect estimate for the velocity based on an entropy optimization of the determined direct estimate for the velocity, thereby generating ranged aligned data, determine an indirect estimate for quadratic phase error in the ranged aligned data based on entropy optimization, and perform a phase gradient autofocus (PGA) process on the ranged aligned data, based on the indirect estimate for the quadratic phase error, thereby generating a motion compensated signal. ### Claim 2 (depends on 1) The radar system of claim 1, wherein the motion compensator is further configured to: perform pulse-by-pulse estimation of a plurality of time shifts to determine the direct estimate for the velocity of the object based on the return signal. ### Claim 3 (depends on 1) The radar system of claim 1, wherein the motion compensator is further configured to: determine the indirect estimate based on entropy optimization of quadratic phase error and a nonlinear motion model. ### Claim 4 (depends on 1) The radar system of claim 1, wherein the motion compensator is further configured to: determine a time delay that maximizes a correlation between a reference pulse and a pulse profile in the return signal; and determine the direct estimate for the velocity of the object based on the time delay. ### Claim 5 (depends on 4) The radar system of claim 4, wherein the reference pulse is a composite of a plurality of pulse profiles in the return signal before the pulse profile. ### Claim 6 (depends on 5) The radar system of claim 5, wherein the reference pulse is a composite of all pulse profiles in the return signal before the pulse profile. ### Claim 7 (depends on 5) The radar system of claim 5, wherein each pulse profile in the plurality of pulse profiles is shifted by a respective determined time delay. ### Claim 8 (depends on 1) The radar system of claim 1, wherein the motion compensator is further configured to: determine respective time delays that maximize respective correlations between respective reference pulses and respective pulse profiles in the return signal for each pulse profile in a plurality of pulse profiles in the return signal; determine a delay vector based on the respective time delays; and determine the direct estimate for the velocity of the object based on the delay vector. ### Claim 9 (depends on 8) The radar system of claim 8, wherein the motion compensator is further configured to: determine a direct estimate for an acceleration of the object based on the delay vector. ### Claim 10 (depends on 9) The radar system of claim 9, wherein the motion compensator is further configured to: determine an optimized velocity, based on the determined velocity, such that the optimized velocity minimizes entropy; determine an optimized acceleration, based on the determined acceleration, such that the optimized acceleration minimizes entropy; and align the plurality of pulse profiles based on the optimized velocity and the optimized acceleration, thereby generating the ranged aligned data. ### Claim 11 (depends on 1) The radar system of claim 1, wherein the motion compensator is further configured to: convert the ranged aligned data to a range-Doppler map; minimize a two dimensional (2D) entropy of the range-Doppler map; and determine the indirect estimate for the quadratic phase error based on the minimized 2D entropy of the range-Doppler map. ### Claim 12 (depends on 1) The radar system of claim 1, wherein the motion compensator is further configured to: perform five iterations of the PGA process on the ranged aligned data. ### Claim 13 (depends on 1) The radar system of claim 1, wherein the return signal comprises information that can be used to reproduce a voice signal generated by a human on the moving object. ### Claim 14 (depends on 1) The radar system of claim 1, wherein the return signal comprises information that can be used to reproduce a signal generated by movement of a human. ### Claim 15 (depends on 1) The radar system of claim 1, wherein the return signal comprises information that can be used to reproduce an acoustic signal. ### Claim 16 (depends on 15) The radar system of claim 15, wherein the motion compensator is further configured to: generate a fingerprint for a source of the acoustic signal, thereby associating the source with the acoustic signal. ### Claim 17 (depends on 16) The radar system of claim 16, wherein the motion compensator is further configured to: determine whether the fingerprint matches a respective fingerprint in a plurality of stored fingerprints; and identify the source in response to a determination that the fingerprint matches a fingerprint in a plurality of stored fingerprints. ### Claim 18 (depends on 1) The radar system of claim 1, wherein the radar system is a millimeter wave (MMW) radar system. ### Claim 19 A radar system, comprising: a radar configured to receive a signal from a moving object; and a motion compensator configured to: determine respective time delays that maximize respective correlations between respective reference pulses and respective pulse profiles in the signal for each pulse profile in a plurality of pulse profiles in the signal, determine a delay vector based on the respective time delays, determine a velocity of the object based on the delay vector, determine an acceleration of the object based on the delay vector, determine an optimized velocity, based on the determined velocity, such that the optimized velocity minimizes entropy, determine an optimized acceleration, based on the determined acceleration, such that the optimized acceleration minimizes entropy, align the plurality of pulse profiles based on the optimized velocity and the optimized acceleration, thereby generating ranged aligned data, convert the ranged aligned data to a range-Doppler map, minimize a two dimensional (2D) entropy of the range-Doppler map, determine an estimate for a quadratic phase error based on the minimized 2D entropy of the range-Doppler map, and perform a phase gradient autofocus (PGA) process on the ranged aligned data, based on the indirect estimate for the quadratic phase error, thereby generating a motion compensated signal. ### Claim 20 A radar system, comprising: a radar configured to: send a signal towards a moving object, and receive a return signal; and a motion compensator configured to: receive the return signal from the radar, determine a direct estimate for a velocity of the object based on the return signal, determine a direct estimate for an acceleration of the object based on the return signal, determine respective indirect estimates for the velocity and acceleration based on an entropy optimization of the determined direct estimate for the velocity and the determined direct estimate for the acceleration, thereby generating ranged aligned data, determine an indirect estimate for quadratic phase error in the ranged aligned data based on entropy optimization, and perform a phase gradient autofocus (PGA) process on the ranged aligned data, based on the indirect estimate for the quadratic phase error, thereby generating a motion compensated signal.