# US 2025/0155554 A1 · Signal analysis device, control circuit, storage medium, and signal analysis method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2025/0155554 A1 - Document ID: US20250155554A1 - Status: Published application - Kind: A1 - Application number: 19/024,691 - Filed: 2025-01-16 - Published: 2025-05-15 - Earliest claimed: 2022-09-05 - Assignees: Mitsubishi Electric Corporation - Applicants: Mitsubishi Electric Corporation - Inventors: Yuji AKIYAMA - Web page: https://patentgrep.com/patent/US20250155554A1 ## CPC - G01S 7/411: {Identification of targets based on measurements of radar reflectivity (G01S7/415 takes precedence)} - G01S 7/354: {Extracting wanted echo-signals (Doppler systems G01S13/50)} - G01S 7/356: {involving particularities of FFT processing} - G01S 13/0209: {Systems with very large relative bandwidth, i.e. larger than 10 %, e.g. baseband, pulse, carrier-free, ultrawideband} - 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 13/878: {Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector (G01S13/874 takes precedence)} - G01S 13/867: {Combination of radar systems with cameras} - 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 signal analysis device includes a transmission unit that modulates chirp signals and transmits the modulated signals toward an observation area; a reception unit that receives the signals transmitted through the observation area, and mixes reception signals with the chirp signals to generate baseband signals; and a reception processing unit that converts the baseband signals, from values in a time domain into values in a frequency domain, combines values in the frequency domain on a per predetermined frequency range basis to thereby convert the values in the frequency domain into values smaller in number than the values in the frequency domain, estimates a coarse reflectance distribution in the observation area, using the smaller number of values, and estimates a reflectance distribution more precise than the coarse reflectance distribution, using the coarse reflectance distribution as an initial value of iterative estimation processing. ## Claims ### Claim 1 A signal analysis device comprising: transmission circuitry to modulate a plurality of chirp signals synchronized with one another, and transmit the modulated signals from a plurality of transmission antennas toward an observation area; reception circuitry to: receive, with a plurality of reception antennas, signals transmitted from the transmission circuitry and passed through the observation area; mix the chirp signals with reception signals received with the plurality of reception antennas to generate a plurality of baseband signals; and convert the plurality of baseband signals from analog signals to digital signals; and reception processing circuitry to: convert the plurality of baseband signals that are digital signals resulting from the conversion, from values in a time domain into values in a frequency domain; combine a plurality of values in the frequency domain on a per predetermined frequency range basis to thereby convert the plurality of values in the frequency domain into values smaller in number than the plurality of values in the frequency domain; to estimate a coarse reflectance distribution in the observation area, using the smaller number of values; and to estimate a reflectance distribution with respect to the observation area, using the coarse reflectance distribution as an initial value of iterative estimation processing, the reflectance distribution being more precise than the coarse reflectance distribution. ### Claim 2 (depends on 1) The signal analysis device according to claim 1, wherein the reception processing circuitry estimates the coarse reflectance distribution, using information obtained by a camera shooting the observation area. ### Claim 3 (depends on 1) The signal analysis device according to claim 1, wherein in combining the values in the frequency domain, the reception processing circuitry removes a range including no meaningful value in the frequency domain. ### Claim 4 (depends on 1) The signal analysis device according to claim 1, wherein the chirp signals are continuous chirp signals. ### Claim 5 (depends on 1) The signal analysis device according to claim 1, wherein the chirp signals are step chirp signals. ### Claim 6 (depends on 1) The signal analysis device according to claim 1, wherein the chirp signals are frequency hopping signals. ### Claim 7 (depends on 1) The signal analysis device according to claim 1, comprising: control circuitry to control generation of the chirp signals, wherein the control circuitry distributes the chirp signals to the transmission circuitry and the reception circuitry by controlling operation of an oscillator that generates the chirp signals. ### Claim 8 (depends on 1) The signal analysis device according to claim 1, comprising: control circuitry to control generation of the chirp signals, wherein the control circuitry distributes the chirp signals to the transmission circuitry and the reception circuitry by controlling operation of a digital-to-analog converter that generates the chirp signals. ### Claim 9 (depends on 1) The signal analysis device according to claim 1, wherein the reception processing circuitry performs coarse estimation more frequently than fine estimation, and when the reception processing circuitry determines that an observation target object is present at a location suitable for observation in the observation area on a basis of the coarse reflectance distribution estimated by the coarse estimation, the reception processing circuitry performs the fine estimation, the coarse estimation estimating the coarse reflectance distribution, the fine estimation estimating a reflectance distribution more precise than the coarse reflectance distribution. ### Claim 10 A control circuit for controlling a signal analysis device, wherein the control circuit causes the signal analysis device to: modulate a plurality of chirp signals synchronized with one another, and transmit the modulated signals from a plurality of transmission antennas toward an observation area; receive, with a plurality of reception antennas, signals transmitted and passed through the observation area, mix the chirp signals with reception signals received with the plurality of reception antennas to generate a plurality of baseband signals, and convert the plurality of baseband signals from analog signals to digital signals; and convert the plurality of baseband signals that are digital signals resulting from the conversion, from values in a time domain into values in a frequency domain, combine a plurality of values in the frequency domain on a per predetermined frequency range basis to thereby convert the plurality of values in the frequency domain into values smaller in number than the plurality of values in the frequency domain, estimate a coarse reflectance distribution in the observation area, using the smaller number of values, and estimate a reflectance distribution with respect to the observation area, using the coarse reflectance distribution as an initial value of iterative estimation processing, the reflectance distribution being more precise than the coarse reflectance distribution. ### Claim 11 A non-transitory storage medium storing a program for controlling a signal analysis device, wherein the program causes the signal analysis device to: modulate a plurality of chirp signals synchronized with one another, and transmit the modulated signals from a plurality of transmission antennas toward an observation area; receive, with a plurality of reception antennas, signals transmitted and passed through the observation area, mix the chirp signals with reception signals received with the plurality of reception antennas to generate a plurality of baseband signals, and convert the plurality of baseband signals from analog signals to digital signals; and convert the plurality of baseband signals that are digital signals resulting from the conversion, from values in a time domain into values in a frequency domain, combine a plurality of values in the frequency domain on a per predetermined frequency range basis to thereby convert the plurality of values in the frequency domain into values smaller in number than the plurality of values in the frequency domain, estimate a coarse reflectance distribution in the observation area, using the smaller number of values, and estimate a reflectance distribution with respect to the observation area, using the coarse reflectance distribution as an initial value of iterative estimation processing, the reflectance distribution being more precise than the coarse reflectance distribution. ### Claim 12 A signal analysis method for use in a signal analysis device, the signal analysis method comprising: modulating a plurality of chirp signals synchronized with one another, and transmitting the modulated signals from a plurality of transmission antennas toward an observation area; receiving, with a plurality of reception antennas, signals transmitted through the observation area, mixing the chirp signals with reception signals received with the plurality of reception antennas to generate a plurality of baseband signals, and converting the plurality of baseband signals from analog signals to digital signals; and converting the plurality of baseband signals that are digital signals resulting from the conversion, from values in a time domain into values in a frequency domain, combining a plurality of values in the frequency domain on a per predetermined frequency range basis to thereby convert the plurality of values in the frequency domain into values smaller in number than the plurality of values in the frequency domain, estimating a coarse reflectance distribution in the observation area, using the smaller number of values, and estimating a reflectance distribution with respect to the observation area, using the coarse reflectance distribution as an initial value of iterative estimation processing, the reflectance distribution being more precise than the coarse reflectance distribution.