# US 10,481,248 B2 · Detection apparatus, underwater detection apparatus and radar apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,481,248 B2 - Document ID: US10481248B2 - Status: Granted - Kind: B2 - Application number: 15/371,051 - Filed: 2016-12-06 - Published: 2017-06-15 - Granted: 2019-11-19 - Earliest claimed: 2015-12-11 - Assignees: Furuno Electric Co., Ltd. - Applicants: Furuno Electric Co., Ltd. - Inventors: Kohei Kozuki; Kohei Iwata - Web page: https://patentgrep.com/patent/US10481248B2 ## CPC - G01S 13/341: {wherein the rate of change of the transmitted frequency is adjusted to give a beat of predetermined constant frequency, e.g. by adjusting the amplitude or frequency of the frequency-modulating signal} - G01S 13/343: {using sawtooth modulation} - G01S 15/34: 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 15/42: Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S15/46) - G01S 15/96: for locating fish - 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 Continuous Transmission Frequency Modulated (CTFM) detection apparatus is provided. The apparatus includes a projector, a sensor, and a hardware processor. The projector is configured to transmit a frequency modulated transmission wave at a given transmission period. The sensor is configured to receive a reflected wave, the reflected wave comprising a reflection of the transmission wave on a target object. The hardware processor is programmed to at least generate a beat signal based at least in part on the transmission wave and the reflected wave, extract asynchronously from the transmission period a processing signal from the beat signal, and generate information related to the target object based on the processing signal. ## Claims ### Claim 1 A Continuous Transmission Frequency Modulated (CTFM) detection apparatus, comprising: a projector configured to transmit a frequency modulated transmission wave at a given transmission period; a sensor configured to receive a reflected wave, the reflected wave comprising a reflection of the transmission wave on a target object; and a hardware processor programmed to at least: generate a beat signal based at least in part on the transmission wave and the reflected wave, extract a plurality of extracted beat signals from the beat signal, each extracted beat signal from the plurality of extracted beat signals being extracted by applying a different gate interval of a plurality of gate intervals to the beat signal, wherein the gate interval for at least some of the extracted beat signals are set at different timings, extract a processing signal from the beat signal, wherein the processing signal is selected from the plurality of extracted beat signals, and generate information related to the target object based on the processing signal. ### Claim 2 (depends on 1) The CTFM detection apparatus of claim 1, wherein the hardware processor is further programmed to at least: calculate an absolute value of a complex spectrum corresponding to each extracted beat signal, each complex spectrum being obtained from a frequency conversion of the extracted beat signal, and select the processing signal from the plurality of extracted beat signals, the selected extracted beat signal corresponding to the complex spectrum with the smallest absolute value. ### Claim 3 (depends on 1) The CTFM detection apparatus of claim 1, wherein the sensor includes a plurality of receiving elements; and the hardware processor is further programmed to at least: generate a plurality of beat signals, wherein the plurality of beat signals includes the beat signal, and wherein each beat signal corresponds to a receiving element from the plurality of receiving elements, based at least in part on the transmission wave and the reflected wave received by the receiving element, generate a representative beat signal based at least in part on the transmission wave and a representative signal, the representative signal being generated from at least one of the reflected waves received by the plurality of receiving elements, extract a plurality of extracted representative beat signals from the representative beat signal, each extracted representative beat signal from the plurality of extracted representative beat signals being extracted applying a gate interval to the representative beat signal, calculate an absolute value of a complex spectrum corresponding to each extracted representative beat signal, each complex spectrum being obtained from a frequency conversion of the extracted representative beat signal, and select the processing signal from the plurality of extracted beat signals, the selected extracted beat signal corresponding to the complex spectrum with the smallest absolute value. ### Claim 4 The CTFM detection apparatus of claim, 1 wherein at least two gate intervals from the plurality of gate intervals overlap a portion of each other in the time domain. ### Claim 5 A Continuous Transmission Frequency Modulated (CTFM) detection apparatus, comprising: a projector configured to transmit a frequency modulated transmission wave at a given transmission period; a sensor configured to receive a reflected wave, the reflected wave comprising a reflection of the transmission wave on a target object; and a hardware processor programmed to at least: generate a beat signal based at least in part on the transmission wave and the reflected wave, detect a beat signal phase jump timing at which a phase change of the beat signal is above a given value, apply a gate interval to the beat signal to extract an extracted beat signal, a center time of the gate interval being shifted from the beat signal phase jump timing, generate a processing signal based on the extracted beat signal, and generate information related to the target object based on the processing signal. ### Claim 6 (depends on 5) The CTFM detection apparatus of claim 5, wherein the hardware processor is further programmed to at least: detect the beat signal phase jump timing by calculating phase change of the beat signal. ### Claim 7 (depends on 5) The CTFM detection apparatus of claim 5, wherein the hardware processor is further programmed to at least: detect the beat signal phase jump timing by calculating frequency change of a signal generated from the reflected wave. ### Claim 8 (depends on 5) The CTFM detection apparatus of claim 5, wherein the hardware processor is further programmed to at least: detect the beat signal phase jump timing based on a position of a given target object relative to the CTFM detection apparatus. ### Claim 9 (depends on 5) The CTFM detection apparatus of claim 5, wherein the sensor includes a plurality of receiving elements configured to receive a plurality of reflected waves including the reflected wave; and the hardware processor is further programmed to at least: generate a plurality of beat signals, wherein the plurality of beat signals includes the beat signal, and wherein each beat signal corresponds to a receiving element from the plurality of receiving elements and is based at least in part on the transmission wave and the reflected wave received by the receiving element, detect the beat signal phase jump timing from a representative signal generated from at least one of the plurality of reflected waves received by the plurality of receiving elements, and extract the extracted beat signal by applying the gate interval to each of the beat signals and generate the processing signal corresponding to each extracted beat signal. ### Claim 10 (depends on 9) The CTFM detection apparatus of claim 9, wherein the hardware processor is further programmed to at least: estimate a direction of the target object using beamforming processing. ### Claim 11 (depends on 1) The CTFM detection apparatus of claim 1, wherein the hardware processor is further programmed to at least: multiply, for each extracted beat signal from the plurality of extracted beat signals, the extracted beat signal by a window function, and generate the processing signal based on the extracted beat signal multiplied by the window function. ### Claim 12 (depends on 5) The CTFM detection apparatus of claim 5, wherein the hardware processor is further programmed to at least: multiply the extracted beat signal by a window function, and generate the processing signal based on the extracted beat signal multiplied by the window function. ### Claim 13 (depends on 1) An underwater detection apparatus comprising the CTFM detection apparatus of claim 1. ### Claim 14 (depends on 1) A radar apparatus comprising the CTFM detection apparatus of claim 1. ### Claim 15 (depends on 5) An underwater detection apparatus comprising the CTFM detection apparatus of claim 5. ### Claim 16 (depends on 5) A radar apparatus comprising the CTFM detection apparatus of claim 5.