# US 2021/0333385 A1 · Enhanced range-velocity finding in frequency-modulated continuous wave radar > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0333385 A1 - Document ID: US20210333385A1 - Status: Published application - Kind: A1 - Application number: 16/857,102 - Filed: 2020-04-23 - Published: 2021-10-28 - Earliest claimed: 2020-04-23 - Assignees: Semiconductor Components Industries, LLC - Applicants: Semiconductor Components Industries, LLC - Inventors: Nader ROHANI; Youssef ATRIS - Web page: https://patentgrep.com/patent/US20210333385A1 ## CPC - G01S 13/343: {using sawtooth modulation} - G01S 13/584: {adapted for simultaneous range and velocity measurements} - G01S 7/352: {Receivers} - G01S 13/862: {Combination of radar systems with sonar systems} - G01S 13/87: Combinations of radar systems, e.g. primary radar and secondary radar - G01S 13/931: of land vehicles - G01S 15/87: Combinations of sonar systems - G01S 15/931: of land vehicles - G01S 7/356: {involving particularities of FFT processing} - G01S 2013/93271: {in the front of the vehicles} - G01S 2013/93272: {in the back of the vehicles} - G01S 2013/93274: {on the side of the vehicles} - G01S 2015/937: {sensor installation details} - H03M 7/40: Conversion to or from variable length codes, e.g. Shannon-Fano code, Huffman code, Morse code - H03M 7/4062: {Coding table adaptation} - H03M 7/70: {Type of the data to be coded, other than image and sound} - 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 - H03M: CODING; DECODING; CODE CONVERSION IN GENERAL (using fluidic means F15C4/00; optical analogue/digital converters G02F7/00; coding, decoding or code conversion, specially adapted for particular applications, see the relevant subclasses, e.g. G01D, G01R, G06F, G06T, G09G, G10L, G11B, G11C, H04B, H04L, H04M, H04N; ciphering or deciphering for cryptography or other purposes involving the need for secrecy G09C) ## Abstract A radar detection method that comprises receiving a signal from each of one or more receive antennas, each received signal including a plurality of chirps, each received signal corresponding to a transmit signal reflected by a reflector; obtaining a range signal by downmixing each received signal with a reference chirp signal; performing a frequency transform on the range signal to obtain, for each chirp in the plurality of chirps, a set of range coefficients; compressing each set of range coefficients to obtain a plurality of compressed coefficient sets, wherein each compressed coefficient set corresponds to a set of range coefficients; storing each compressed coefficient set in a buffer; decompressing each compressed coefficient set to obtain buffered sets of range coefficients; processing the buffered sets of range coefficients to determine a range to a reflector of the transmit signal; and reporting the range to an electronic control unit. ## Claims ### Claim 1 A radar detection method that comprises: receiving a signal from each of one or more receive antennas, each received signal including a plurality of chirps, each received signal corresponding to a transmit signal reflected by a reflector; obtaining a range signal by downmixing each received signal with a reference chirp signal; performing a frequency transform on the range signal to obtain, for each chirp in the plurality of chirps, a set of range coefficients; compressing each set of range coefficients to obtain a plurality of compressed coefficient sets, wherein each compressed coefficient set corresponds to a set of range coefficients; storing each compressed coefficient set in a buffer; decompressing each compressed coefficient set to obtain buffered sets of range coefficients; processing the buffered sets of range coefficients to determine a range to a reflector of the transmit signal; and reporting the range to an electronic control unit. ### Claim 2 (depends on 1) The radar detection method of claim 1, wherein said compressing and said decompressing each include using a Huffman encoding dictionary. ### Claim 3 (depends on 2) The radar detection method of claim 2, wherein said compressing includes generating a Huffman encoding dictionary for each set of range coefficients based on a symbol probability within the set of range coefficients. ### Claim 4 (depends on 3) The radar detection method of claim 3, wherein said Huffman encoding dictionary is stored in the buffer with a corresponding set of range coefficients. ### Claim 5 (depends on 1) The radar detection method of claim 1, wherein prior to said compressing, each range coefficient in the set of range coefficients is separated into real and imaginary parts, normalized, quantized, and standardized in accordance with a block floating-point algorithm. ### Claim 6 (depends on 5) The radar detection method of claim 5, wherein each normalized, quantized, and standardized real and imaginary part is represented as a 20-bit floating point number. ### Claim 7 (depends on 6) The radar detection method of claim 6, wherein the 20-bit floating point number includes a 1-bit sign value, a 4-bit exponential value and a 15-bit fractional value. ### Claim 8 (depends on 1) The radar detection method of claim 1, wherein processing the buffered sets of range coefficients to determine the range to the reflector of the transmit signal includes: forming a range matrix having the buffered sets of range coefficients as rows; performing frequency transforms on columns of the range matrix to obtain sets of velocity coefficients; forming a velocity cube having sets of velocity coefficients associated with different antennas as layers; performing frequency transforms across layers of the velocity cube to obtain sets of azimuth coefficients; identifying energy peaks within the velocity cube representing reflectors of the transmit signal; and reporting for each energy peak an associated range, velocity, and azimuth. ### Claim 9 A radar transceiver, comprising: one or more transmitter circuits configured to drive a transmit antenna to emit a first transmit signal, the first transmit signal comprising a plurality of chirps; a receiver configured to detect a second signal using a receive antenna during a detection period; and a processor coupled to the one or more transmitter circuits and the receiver, and configured to: downmix the second signal with a reference chirp signal to obtain a range signal; perform a frequency transform on the range signal to obtain, for each chirp in the plurality of chirps, a set of range coefficients; compress each set of range coefficients to obtain a compressed coefficient set; store each compressed coefficient set in a buffer; decompress each compressed coefficient set to obtain buffered sets of range coefficients; and process the buffered sets of range coefficients to determine a range to a reflector of the first transmit signal. ### Claim 10 (depends on 9) The radar transceiver of claim 9, wherein said compressing and said decompressing each include using a Huffman encoding dictionary. ### Claim 11 (depends on 10) The radar transceiver of claim 10, wherein said compressing includes generating a Huffman encoding dictionary for each set of range coefficients based on a symbol probability within the set of range coefficients. ### Claim 12 (depends on 10) The radar transceiver of claim 10, wherein said Huffman encoding dictionary is stored in the buffer with a corresponding set of range coefficients. ### Claim 13 (depends on 9) The radar transceiver of claim 9, wherein prior to said compressing, each range coefficient in the set of range coefficients is separated into real and imaginary parts, normalized, quantized, and standardized in accordance with a block floating-point algorithm. ### Claim 14 (depends on 13) The radar transceiver of claim 13, wherein each normalized, quantized, and standardized real part and imaginary part corresponds to a 20-bit floating point number corresponding to a 1-bit sign value, a 4-bit exponential value and a 15-bit fractional value. ### Claim 15 (depends on 9) The radar transceiver of claim 9, wherein processing the buffered sets of range coefficients to determine the range to the reflector of the first transmit signal includes: forming a range matrix having the buffered sets of range coefficients as rows; performing frequency transforms on columns of the range matrix to obtain sets of velocity coefficients; forming a velocity cube, the velocity cube having sets of velocity coefficients associated with different antennas as layers; performing frequency transforms across layers of the velocity cube to obtain sets of azimuth coefficients; identifying a plurality of energy peaks within the velocity cube, wherein the plurality of energy peaks represents reflectors of the first transmit signal; and reporting a range, velocity and azimuth corresponding to one or more energy peaks of the plurality of energy peaks. ### Claim 16 A method of generating a velocity matrix in a radar system, comprising: receiving a range signal using processor; producing a set of range coefficients by performing a first fast Fourier transform on the range signal, the set of range coefficients corresponding to a first matrix; encoding the set of range coefficients of the first matrix in accordance with a Huffman encoding algorithm; producing a second matrix by transposing the first matrix, the second matrix having a set of elements; decoding the set of elements of the second matrix in accordance with the Huffman encoding algorithm; and generating a velocity matrix by performing a second fast Fourier transform on the set of elements. ### Claim 17 (depends on 16) The method of generating a velocity matrix in a radar system of claim 16, wherein transposing the first matrix comprises storing elements of the first matrix in a transpose buffer. ### Claim 18 (depends on 17) The method of generating a velocity matrix in a radar system of claim 17, wherein encoding the set of range coefficients of the first matrix in accordance with the Huffman encoding algorithm comprises generating a Huffman dictionary and storing the Huffman dictionary in the transpose buffer. ### Claim 19 (depends on 18) The method of generating a velocity matrix in a radar system of claim 18, wherein decoding the set of elements of the second matrix in accordance with the Huffman encoding algorithm comprises applying the Huffman dictionary to the set of elements of the second matrix. ### Claim 20 A radar system, comprising: a memory configured to receive a plurality of range signals; a first processor coupled to the memory, wherein the first processor is configured to determine a plurality of range coefficients by performing a first frequency transform on the plurality of range signals; a first codec coupled to the first processor, wherein the first codec is configured to compress the plurality of range signals as a first set of elements using a Huffman encoding algorithm; a second processor configured to generate a second set of elements by performing a transpose operation on the first set of elements; a second codec configured to decompress the second set of elements; and a third processor configured to determine a velocity matrix by performing a second frequency transform on the second set of elements. ### Claim 21 (depends on 20) The radar system of claim 20, wherein the memory is a FIFO buffer memory, wherein the first codec and the second codec are different, and wherein the first processor, the second processor, and the third processor are different.