# US 11,307,289 B2 · Radar device and method for changing reception gain of radar device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,307,289 B2 - Document ID: US11307289B2 - Status: Granted - Kind: B2 - Application number: 16/639,732 - Filed: 2018-07-31 - Published: 2021-04-29 - Granted: 2022-04-19 - Earliest claimed: 2017-08-18 - Assignees: Furuno Electric Co., Ltd. - Applicants: Furuno Electric Co., Ltd. - Inventors: Shuhei Inoue - Web page: https://patentgrep.com/patent/US11307289B2 ## CPC - G01S 7/025: {involving the transmission of linearly polarised waves} - G01S 7/34: Gain of receiver varied automatically during pulse-recurrence period, e.g. anti-clutter gain control - G01S 7/40: Means for monitoring or calibrating - G01S 7/4021: {of receivers} - G01W 1/00: Meteorology - G01S 7/4069: {involving a RF signal injection} - G01S 13/95: for meteorological use - Y02A 90/10: Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation - 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 - G01W: METEOROLOGY (radar, sonar, lidar or analogous systems, designed for meteorological use G01S13/95, G01S15/88, G01S17/95) - Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE ## Abstract A radar device (1) includes a frequency conversion part (12) which converts a frequency of an echo signal obtained by reflecting a detection signal and receiving the reflected detection signal by an antenna (10), and amplifies a signal level thereof. The radar device (1) includes a path switching part (20) which outputs, as a calibration signal, to the frequency conversion part (12), the transmission signal output by the transmission signal generation part (11) at a timing while the transmission signal is output to the antenna (10). A gain adjustment part (23) changes an amplification gain of the frequency conversion part (12) on the basis of a signal level of the calibration signal input to the frequency conversion part (12) and a signal level of the calibration signal having been amplified by the frequency conversion part (12). ## Claims ### Claim 1 A radar device, comprising: a transmission signal generator which repeatedly generates, at a time interval, a transmission signal to be output to an antenna in order to transmit a detection signal from the antenna; a frequency convertor which converts a frequency of an echo signal obtained by reflecting the detection signal and receiving the detection signal by the antenna, and amplifies a signal level thereof, within a period from a time when the transmission signal generator completes outputting the transmission signal to the antenna to a time when a next one of the transmission signal starts to be output to the antenna; a processing circuitry which processes and outputs a signal input from the frequency convertor; a path switch which outputs the transmission signal output by the transmission signal generator to the frequency convertor as a calibration signal at a timing while the transmission signal is being output to the antenna; and an amplification gain adjuster which changes an amplification gain of the frequency convertor based on a signal level of the calibration signal input to the frequency convertor and a signal level of the calibration signal having been amplified by the frequency convertor. ### Claim 2 (depends on 1) The radar device according to claim 1, comprising: a circulator which separates signal paths, causes the transmission signal generated by the transmission signal generator to be output to the antenna, and causes the echo signal received by the antenna to be output to the frequency convertor; and a reception amplifier which amplifies and outputs to the frequency convertor a signal input from the circulator, wherein an input of the echo signal from the reception amplifier to the frequency convertor is blocked while the transmission signal generator is outputting the transmission signal to the antenna. ### Claim 3 (depends on 1) The radar device according to claim 1, wherein the path switch comprises a calibration signal path which is a signal path in which the transmission signal output by the transmission signal generator is output to the frequency convertor as a calibration signal, and the path switch disconnects the calibration signal path before the transmission signal generator completes outputting the transmission signal to the antenna. ### Claim 4 (depends on 3) The radar device according to claim 3, wherein the path switch connects the calibration signal path before the transmission signal generator starts outputting the transmission signal to the antenna. ### Claim 5 (depends on 1) The radar device according to claim 1, wherein the amplification gain adjuster changes the amplification gain of the frequency convertor based on at least a temperature characteristic of a circulator which is disposed between the frequency convertor and the antenna and switches signal paths. ### Claim 6 (depends on 1) The radar device according to claim 1, wherein the frequency convertor has two channels which frequency-convert two polarized waves orthogonal to each other and amplify signal levels thereof, respectively, and the amplification gain adjuster changes amplification gains of the respective channels, and makes a ratio of a signal level of the calibration signal input to the respective channels to a signal level of the calibration signal having been amplified by the respective channels be consistent between the two channels. ### Claim 7 (depends on 1) The radar device according to claim 1, wherein the amplification gain of the frequency convertor is changed by the amplification gain adjuster without stopping transmission of the detection signal from the antenna and without changing a transmission interval of the detection signal. ### Claim 8 (depends on 1) The radar device according to claim 1, comprising: a gain target value storage which stores a gain target value which is a target value of a gain of the frequency convertor or a target value of a gain of a reception signal path comprising the frequency convertor, wherein the amplification gain adjuster changes the amplification gain of the frequency convertor based on the gain target value stored in the gain target value storage, and the gain target value stored in the gain target value storage is configured to be changeable. ### Claim 9 (depends on 1) The radar device according to claim 1, wherein the processing circuitry is capable of outputting the calibration signal that has been frequency-converted and amplified by the frequency convertor. ### Claim 10 (depends on 1) The radar device according to claim 1, wherein the radar device obtains weather observation data. ### Claim 11 A method for changing a reception gain of a radar device, comprising: repeatedly generating, at a time interval, a transmission signal to be output to an antenna in order to transmit a detection signal from the antenna by a transmission signal generator; converting a frequency of an echo signal obtained by reflecting the detection signal and receiving the detection signal by the antenna and amplifying a signal level thereof, by a frequency convertor, within a period from a time when the transmission signal generator completes outputting the transmission signal to the antenna to a time when a next one of the transmission signal starts to be output to the antenna, and performing processing on an amplified signal by a processing circuitry; inputting the transmission signal to the frequency convertor by a path switch as a calibration signal at a timing while the transmission signal is being output to the antenna, and converting a frequency of the calibration signal by the frequency convertor and amplifying a signal level thereof; and changing an amplification gain of the frequency convertor, by an amplification gain adjuster, based on a signal level of the calibration signal input to the frequency convertor and a signal level of the calibration signal having been amplified by the frequency convertor.