# US 10,371,799 B1 · Methods of calibration for radar apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,371,799 B1 - Document ID: US10371799B1 - Status: Granted - Kind: B1 - Application number: 15/269,703 - Filed: 2016-09-19 - Granted: 2019-08-06 - Earliest claimed: 2013-12-20 - Assignees: Delta Mobile Systems, Inc - Applicants: Delta Mobile Systems, Inc - Inventors: James C Graves, Jr.; Debra A Jones - Web page: https://patentgrep.com/patent/US10371799B1 ## CPC - G01S 7/4008: {of transmitters} - G01S 7/35: Details of non-pulse systems - G01S 7/354: {Extracting wanted echo-signals (Doppler systems G01S13/50)} - G01S 7/4004: {of parts of a radar system} - G01S 7/4017: {of HF systems} - G01S 7/4021: {of receivers} - G01S 7/41: using analysis of echo signal for target characterisation; Target signature; Target cross-section - G01S 7/411: {Identification of targets based on measurements of radar reflectivity (G01S7/415 takes precedence)} - 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 13/343: {using sawtooth modulation} - G01S 13/584: {adapted for simultaneous range and velocity measurements} - G01S 7/038: {Feedthrough nulling circuits} - G01S 7/4013: {involving adjustment of the transmitted power} - 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 radar apparatus is calibrated while operating in a configuration such that the receiver obtains substantially no reflection from the transmitter. The resultant received signal is written into the compensation signal memory for use during normal operation. The calibration environment is achieved by operating the radar apparatus in a quiet environment or by operating a quieting switch within the radar apparatus to quiet the reflected radar signal. ## Claims ### Claim 1 A method of calibrating a radar apparatus prior to any interpretation of a received radar signal, comprising the steps of: (a) deploying a radar apparatus configured to use a sweep signal for modulating a transmit signal and compensate a received radar signal based on a compensation signal; (b) operating a transmitter and a receiver of the radar apparatus in a quieted environment using one or more of i) a quiet space using absorptive material or ii) a dummy load connected to the transmitter or iii) a termination load connected to a receiver input of the receiver to quiet the receiver input; and (c) storing in a compensation signal memory of the radar apparatus essentially an entirety of the received signal as the compensation signal. ### Claim 2 (depends on 1) A method of calibrating a radar apparatus according to claim 1, wherein said step (c) of storing essentially the entirety of the received signal as the compensation signal comprises the substep of (c1) high-pass filtering the received signal before storing essentially an entirety of an unaltered version of the received signal as the compensation signal. ### Claim 3 (depends on 1) A method of calibrating a radar apparatus according to claim 1, wherein said calibration prior to any interpretation comprises calibration prior to any transformation or detection processing of the received radar signal. ### Claim 4 (depends on 3) A method of calibrating a radar apparatus according to claim 3, wherein said calibration prior to any transformation or detection processing of the received radar signal comprises calibration of the received radar signal prior to frequency transformation into a frequency domain and subsequent peak detection. ### Claim 5 (depends on 1) A method of calibrating a radar apparatus according to claim 1, wherein said step (a) of deploying the radar apparatus further comprises the step of (a1) deploying the radar apparatus in the quieted environment using the absorptive material; and wherein said step (b) of operating the radar apparatus further comprises the step of (b1) measuring a received signal received by the receiver when essentially all transmit signals are absorbed by operating in the quieted environment using the absorptive material. ### Claim 6 (depends on 1) A method of calibrating a radar apparatus according to claim 1, wherein said step (a) of deploying the radar apparatus further comprises the step of (a1) deploying a radar apparatus with a quieting switch; wherein said step (b) of operating further comprises the steps of (b1) operating the quieting switch to quiet the reflected radar signal, wherein the quieting switch one or both of I) couples the transmitter to ground via the dummy load or II) couples the receiver to ground via the termination load; and (b2) measuring a received signal received by the receiver when essentially all transmit signals are quieted by operating the quieting switch of said step (b1); and wherein said step (c) of storing a compensation signal further comprises the step of (c1) adjusting the compensation signal previously stored in said step (c) based on a measurement of the received signal in step (b2). ### Claim 7 (depends on 6) A method of calibrating a radar apparatus according to claim 6, wherein said step (b1) of operating the quieting switch to quiet the reflected radar signal further comprises the step of (b1a) switching the radar signal from the transmitter to a dummy load to absorb essentially an entirety of the radar signal; and wherein said step (c1) of adjusting the compensation signal previously stored further comprises the step of (c1a) adjusting the compensation signal previously stored in said step based on a measurement of the received signal when said step (b1a) switches the transmit signal to absorb essentially an entirety of the radar signal. ### Claim 8 (depends on 6) A method of calibrating a radar apparatus according to claim 6, wherein said step (b1) of operating a quieting switch to quiet the reflected radar signal further comprises the step of (b1a) switching the radar apparatus receiver to a termination load to quiet essentially an entirety of the reflected radar signal; and wherein said step (c1) of adjusting the compensation signal previously stored further comprises the step of (c1a) adjusting the compensation signal previously stored in said step (c) based on a measurement of the received signal when said step (b1a) switches to a termination load to quiet essentially an entirety of the reflected radar signal. ### Claim 9 (depends on 1) A method of calibrating a radar apparatus according to claim 1, wherein said step (b) of operating the transmitter and the receiver further comprises the step of (b1) operating the transmitter and the receiver at multiple sets of operating parameter values; and wherein said step (c) of storing the compensation signal further comprises the step of (c1) storing a plurality of compensation signals each associated with a different set of the operating parameter values. ### Claim 10 (depends on 9) A method of calibrating a radar apparatus according to claim 9, wherein the parameter values of the radar apparatus are chosen from the group consisting of receive gain, frequency, transmit power, sampling rate, bandwidth, and ramp time. ### Claim 11 (depends on 1) A method of calibrating a radar apparatus according to claim 1, wherein said step (b) of operating in a quieted environment comprises the substep of (b1) operating in a quiet space using absorptive material configured to absorb signals present in the physical space between antennas for the transmitter and the receiver. ### Claim 12 (depends on 1) A method of calibrating a radar apparatus according to claim 1, wherein said step (b) of operating in a quieted environment comprises the substep of (b1) using a dummy load connected to the transmitter. ### Claim 13 (depends on 1) A method of calibrating a radar apparatus according to claim 1, wherein said step (b) of operating in a quieted environment comprises the substep of (b1) using a termination load connected to a receiver input of a receiver to quiet the receiver input. ### Claim 14 (depends on 1) A method of calibrating a radar apparatus according to claim 1, wherein said step (c) of storing comprises the substep of (c1) storing essentially an entirety of an unaltered version of the received signal as the compensation signal. ### Claim 15 A method of calibrating a radar apparatus, comprising the steps of: (a) deploying a radar apparatus with a quieting switch configured to use a sweep signal for modulating a transmit signal and compensate a received radar signal based on a compensation signal; (b) operating a transmitter and a receiver of the radar apparatus; (c) configuring the radar apparatus such that the receiver obtains substantially no reflection from the transmitter further comprising the steps of (c1) operating the quieting switch to quiet the reflected radar signal and (c2) measuring a received signal received by the receiver when essentially all transmit signals are quieted by operating the quieting switch of said step (c1); and (d) storing in a compensation signal memory of the radar apparatus essentially an entirety of the received signal as the compensation signal further comprising the step of (d1) adjusting the compensation signal previously stored in said step (d) based on a measurement of the received signal in step (c2); wherein said step (c1) of operating the quieting switch to quiet the reflected radar signal further comprises the step of (c1a) switching the radar signal from the transmitter to a dummy load to absorb essentially an entirety of the radar signal; and wherein said step (d1) of adjusting the compensation signal previously stored further comprises the step of (d1a) adjusting the compensation signal previously stored in said step (d) based on a measurement of the received signal when said step (c1a) switches the transmit signal to absorb essentially an entirety of the radar signal. ### Claim 16 A method of calibrating a radar apparatus, comprising the steps of: (a) deploying a radar apparatus with a quieting switch configured to use a sweep signal for modulating a transmit signal and compensate a received radar signal based on a compensation signal; (b) operating a transmitter and a receiver of the radar apparatus; (c) configuring the radar apparatus such that the receiver obtains substantially no reflection from the transmitter further comprising the steps of (c1) operating the quieting switch to quiet the reflected radar signal and (c2) measuring a received signal received by the receiver when essentially all transmit signals are quieted by operating the quieting switch of said step (c1); and (d) storing in a compensation signal memory of the radar apparatus essentially an entirety of the received signal as the compensation signal further comprising the step of (d1) adjusting the compensation signal previously stored in said step (d) based on a measurement of the received signal in step (c2); wherein said step (c1) of operating a quieting switch to quiet the reflected radar signal further comprises the step of (c1a) switching the radar apparatus receiver to a termination load to quiet essentially an entirety of the reflected radar signal; and wherein said step (d1) of adjusting the compensation signal previously stored further comprises the step of (d1a) adjusting the compensation signal previously stored in said step (d) based on a measurement of the received signal when said step (c1a) switches to a termination load to quiet essentially an entirety of the reflected radar signal.