On-field phase calibration

Abstract

A radar system is provided that includes a radar transceiver integrated circuit (IC) (302) and a processor (308) coupled to the radar transceiver IC (302). The radar transceiver IC includes a chirp generator (314) configured to generate a plurality of chirp signals and a phase shifter (316) configured to induce a signal phase shift. The radar transceiver IC is configured to transmit a frame of chirps based on the plurality of chirp signals and generate a plurality of digital signals, each digital signal corresponding to a respective reflection received based on the plurality of chirp signals. The processor (308) is configured to control the phase shifter (316) to induce a signal phase shift in a first subset of the plurality of chirp signals and to determine the phase shift induced in the first subset of the chirp signals by the phase shifter based on the digital signals.

Description

[Technical Field]

[0001] A radar system transmits electromagnetic signals, which are reflected by any object within the radar system's path. By capturing these reflected signals, the radar system can evaluate the detected object.

[0002] Beamforming is a signal processing technique used with sensor arrays for directional signal transmission or reception. Spatial selectivity is achieved by using adaptive or fixed receive / transmit beam patterns. Doppler-divided multiple access ("DDMA") is also a signal processing technique used with sensor arrays to identify unique transmit array elements within the receive path.

[0003] Electronic devices employing beamforming or DDMA techniques include transmit ("TX") phase shifters. These phase shifters exhibit device-dependent nonlinearity, resulting in a nonlinear mapping between the desired programmed phase and the actual programmed phase. To overcome such nonlinearity, the phase shifters may be calibrated at the factory during the manufacturing of the electronic device incorporating them. However, factory calibration may be insufficient to capture the effects of temperature / aging over the device's lifetime.

[0004] Alternatively, an internal loopback procedure can be used to determine the phase response of each transmit channel using a test signal generated in the transmit channel and provided to the receive channel via the internal loopback path. The phase response can then be used to adjust the transmit signal to calibrate the phase shift at an arbitrary offset. However, such on-chip loopback calibration may not be desirable for calibrating phase shifts caused by onboard routing mismatches. [Overview of the project]

[0005] In one embodiment, the radar system includes a radar transceiver integrated circuit (IC) and a processor coupled to the radar transceiver IC. The radar transceiver IC includes a chirp generator configured to generate a plurality of chirp signals and a phase shifter configured to induce a signal phase shift. The radar transceiver IC is configured to transmit a frame of chirps based on the plurality of chirp signals and to generate a plurality of digital signals, each digital signal corresponding to a reflection received based on the plurality of chirp signals. The processor is configured to control the phase shifter to induce a signal phase shift in a first subset of the chirp signals among the plurality of chirp signals and to determine, based on the digital signals, the phase shift induced by the phase shifter in the first subset of the chirp signals.

[0006] In another embodiment, a method includes generating a plurality of chirp signals, inducing a signal phase shift in a first subset of the chirp signals, and initiating the transmission of a chirp frame based on the plurality of chirp signals. This method also includes generating a plurality of digital signals in response to receiving reflected chirps of the plurality of chirp signals of a chirp frame, and determining, based on the digital signals, the phase shift induced in the first subset of the chirp signals by a phase shifter.

[0007] The drawing is as follows: [Brief explanation of the drawing]

[0008] [Figure 1] This is a signal diagram of a chirp signal on an amplitude-time plot, following one example.

[0009] [Figure 2] This is a signal diagram of the chirp signal in Figure 1 on a frequency-time plot, following one example.

[0010] [Figure 3]Block diagram of an FMCW radar system according to an example.

[0011] [Figure 4] Block diagram of an FMCW radar system according to another example.

[0012] [Figure 5] An example of a chirp transmission frame according to an example.

[0013] [Figure 6] An example of a matrix of analog-digital samples according to an example.

[0014] [Figure 7] A diagram illustrating a 2D-FFT matrix according to an example.

[0015] [Figure 8] A flowchart of a method for phase shift calibration according to an example.

[0016] [Figure 9] An example of a chirp transmission frame according to an example.

[0017] [Figure 10] An example of a matrix for grouping analog-digital samples according to an example.

[0018] [Figure 11] An example illustrating a 2D-FFT matrix based on the matrix of FIG. 10 according to an example.

[0019] [Figure 12] An example of an indexing scheme for Doppler indices for a 2D-FFT having odd rows according to an example.

[0020] [Figure 13]This is an example of an indexing scheme for Doppler indexing for 2D-FFT with an even number of rows, following one example. [Modes for carrying out the invention]

[0021] Millimeter waves (mmWave) are a special class of radar technology that uses short-wavelength electromagnetic waves. In this class of millimeter-wave technology, called FMCW (frequency-modulated continuous wave), FMCW radar continuously transmits frequency-modulated signals to measure range, angle, and velocity. In a radar system, an electromagnetic signal is transmitted, and any object in the radar system's path reflects that signal. In signals used in FMCW radar, the frequency increases linearly with time. This type of signal is also called a chirp. Figure 1 shows the signal diagram 100 of a typical chirp signal 102, with the magnitude (amplitude) as a function of time. Figure 2 shows the chirp signal 102 from Figure 1, with the frequency as a function of time. The chirp signal 102 is characterized by its starting frequency (fc) 200, bandwidth (B) 202, and duration (Tc) 204. The gradient of the chirp signal captures the rate of change of frequency.

[0022] Figure 3 illustrates a block diagram of the FMCW radar system 300, which is configured to transmit chirp signals, such as chirp signal 102, and to capture signals reflected by any object in the path of the FMCW radar system. As shown, the radar system 300 includes a radar transceiver integrated circuit (IC) 302 and a processing unit 304. The processing unit 304 is coupled to the radar transceiver IC 302 via a serial interface 306 to transmit data to and receive data from the radar transceiver IC 302. In one example, the serial interface 306 may be a high-speed serial interface such as a low-voltage differential signaling (LVDS) interface. In another example, the serial interface may be a low-speed SPI (serial peripheral interface).

[0023] The transceiver IC302 includes functionality to generate multiple digital intermediate frequency (IF) signals (alternatively referred to as dechirp signals, beat signals, or raw radar signals) from reflected chirp. The transceiver IC302 may also include functionality to perform some signal processing of the received radar signal within the transceiver IC and provide the results of this signal processing to the processing unit 304 via the serial interface 306. In one example, the radar transceiver IC302 performs a range fast Fourier transform (FFT) for each radar frame. In another example, the radar transceiver IC302 performs both a range FFT and a Doppler FFT for each radar frame.

[0024] The processing unit 304 processes data received from the radar transceiver IC 302 to complete any remaining signal processing, including functionality to determine, for example, the range, velocity, position, and / or angle of any detected object. The processing unit 304 may also include functionality to perform post-processing of information about the detected object, such as tracking the object and determining its velocity and direction of movement. The processing unit 304 may perform phase shifter calibration according to any example of calibration described herein. The processing unit 304 may include any suitable processor or combination of processors (indicated as processor 308) as needed for the processing throughput of application examples using radar data. For example, the processing unit 304 may include a digital signal processor (DSP), a microcontroller (MCU), a system of computing (SOC) combining both DSP and MCU processing, or a floating-point gate array (FPGA) and a DSP. The processing unit 304 also includes computer-readable storage memory 310 for storing phase calibration data.

[0025] The transceiver IC 302 includes a local oscillator 312, a ramp generation component 314, a phase shifter 316, a transmitting antenna 318, a receiving antenna 320, a mixer 322, an analog-to-digital converter (ADC) 324, and a digital signal processor (DSP) 326. Figure 3 shows a single typical transmit and receive chain, but in some examples, multiple chains may be used to support multiple transmit and receive antennas.

[0026] The local oscillator 312 is operable to provide a reference signal (such as timing and / or reference frequency) to the ramp generation component 314. In some examples, the local oscillator 312 itself may provide a frequency ramp centered on a lower frequency, which can be converted to a transmission frequency by the ramp generation component 314. The ramp generation component 314 is configured to provide the resulting ramp signal to a phase shifter 316 via line 330. The phase shifter 316 may be controlled by the processing unit 304 to apply a phase shift to the generated ramp signal on line 330 when a phase shift is required, for example, in beamforming or DDMA radar techniques. The phase shifter 316 may change the phase of the ramp signal, or it may allow the ramp signal to pass through line 332 to the transmitting antenna 318 without being changed. Based on the prior calibration of the radar system 300, the processing unit 304 may access phase shift values ​​(e.g., from storage 310) for a specific desired phase shift value so that the phase shifter 316 applies a phase shift to achieve the expected result in the signal transmitted by the transmitting antenna 318, and the transmitting antenna 318 may operate to transmit those signals wirelessly.

[0027] In some examples, a series of chirp or chirpened continuous wave (CW) signals are generated in a ramp generation component 314 based on input from a local oscillator 312, and transmitted wirelessly by a transmitting antenna 318. The transmitted chirp signals are reflected from any objects within the range and coverage of the radar beam.

[0028] The receiving antenna 320 is operable to wirelessly receive signals and provide the received signals to the mixer 322 on line 334. The mixer 322 can then also receive signals from the ramp generating component 314 on line 332, mix the signals from the receiving antenna 320 with the signals from the ramp generating component 314, and send the resulting mixed signal to the ADC 324. The ADC 324 is operable to convert analog signals to digital signals. The DSP 326 is operable to receive signals from the ADC 324 via line 336 and process the digital signals.

[0029] In some examples, the transmitted chirp signal from the transmitting antenna 318 is reflected from the object, the reflected signal is received by antenna 320 and passed to mixer 322. Mixer 322 mixes the received signal with the transmitted frequency ramp to generate an analog intermediate frequency (IF) signal on line 338. The analog IF signal is sampled by ADC 324 to generate a digital IF signal on line 336. The digital IF signal is processed and analyzed by DSP 326 to determine the velocity and range of the object in the beam.

[0030] The radar system 300 in Figure 3 can be used, for example, in a DDMA radar technique in which the same transmitter can transmit signals with or without phase shift. In an example of beamforming, Figure 4 is provided. Figure 4 illustrates a radar system 400 having multiple transmission paths, including similar elements to those described above for Figure 3, one of which includes a phase shifter 316, a transmitting antenna 318, and a line 332, and another which includes an additional transmitting antenna 402 coupled to a ramp generating component 314 by a line 404 without a phase shifter. Alternatively, a phase shifter (not shown) may be coupled to the transmitting antenna 402 and may be unactivated or activated to apply a zero phase shift in the transmission sequence, resulting in no phase shift in the transmitted signal. Furthermore, a DDMA radar technique can be implemented using the radar system 400 in Figure 4.

[0031] Determining the range of objects in the beam involves performing an FFT on the digitized sample, where the peak frequencies in the range FFT directly correspond to the ranges of various objects in the scene. While the peak frequencies in the range FFT directly correspond to the object range, the phase of these peaks is extremely sensitive to even slight changes in the object's range. For example, a change in the object's position of 1 / 4 wavelength (approximately 1 mm at 77 GHz) translates to a complete 180-degree phase inversion. This phase sensitivity is fundamental to the radar's ability to estimate the frequency of oscillating objects. It also forms the basis for velocity estimation. To resolve the scene in the velocity dimension, the radar may transmit a sequence of temporally equal-spacing chirps 500 in units called frames 502, as illustrated in Figure 5. Each frame 502 may contain N chirps that are equally spaced (as shown) or asymmetrically spaced.

[0032] Figure 6 illustrates a matrix 600 that shows the ADC samples corresponding to N chirps in a frame, arranged according to chirp index 602 and ADC sample index 604. In the signal processing chain, a device such as DSP326 performs a range FFT on the digitized samples corresponding to each chirp 500, and the output is stored as consecutive rows in the matrix. Each row of matrix 600 contains the ADC samples from each chirp 500. Consecutive rows contain the data across the chirps 500. Subsequently, a Doppler FFT is performed across the columns of matrix 600 to obtain a 2D-FFT of the digitized samples corresponding to frame 502.

[0033] Figure 7 illustrates a 2D-FFT matrix 700 arranged according to an example, with Doppler index 702 and range index 704. Peaks 706, 708, 710, and 712 in the 2D-FFT matrix 700 correspond to detected objects. The positions of each peak 706, 708, 710, and 712 in the 2D-FFT matrix correspond to the range and Doppler (relative to the radar) of the object. The 2D-FFT matrix 700 is sometimes called a "range-Doppler" matrix. Also, each cell in the 2D-FFT matrix 700 is sometimes called a "range-Doppler" cell.

[0034] Figure 8 illustrates a flowchart of a phase shifter calibration technique 800 following an example. A processor (e.g., processing unit 304 in Figures 3 and 3b) can be programmed to control a phase shifter to apply a specific phase shift to a ramp signal used in a radar system. In an ideal system, the phase shift realized in the system may match or be substantially equal to the desired phase shift. However, depending on factors such as device characteristics and other non-ideal parameters for a particular phase shifter, the programmed phase may not be the actual phase applied to the signal. Therefore, the processor may be programmed to examine the factory-calibrated calibration value for use with a particular phase shifter and modify the programmed phase so that the phase shifter applies the desired phase to the signal. Thus, phase shifter calibration is a factor in achieving the desired phase signal correction. However, phase shifters can change over time, with earlier calibration values ​​becoming older. In this case, the phase shifter may drift and begin to apply the wrong phase to the signal again. Therefore, the phase shifter may need to be recalibrated. In addition, routing mismatches between multiple transmitter paths may further contribute to the difference between the actual phase shift and the phase shift that is desired to be applied to the signal. Technique 800 provides a method for calibrating a phase shifter, regardless of whether the radar system in which the phase shifter is incorporated is calibrated at its manufacturing facility or calibrated in the field.

[0035] Technique 800 begins with the start of transmission 802 of a frame of chirps having alternating phase shifts. A ramp generator, such as ramp generation component 314, is controlled to generate a series of similar chirps, but a series of first subsets (e.g., a series of alternate chirps) are modified by a first phase shift before being transmitted by the transmitting antenna, while a series of second subsets (e.g., a series of chirps not belonging to the first subset) may remain unmodified or may be modified by a second phase shift before being transmitted. Referring to Figure 9, an alternating chirp frame 900 is shown according to an example. In a frame of chirps 900, odd-numbered chirps 901, 903, 905 (e.g., 1st, 3rd, n-1st, etc.) are transmitted without a phase shifter applying a desired or intended phase shift to the ramp signal from the ramp generator. Alternatively, the phase shifter may be controlled to apply a zero phase shift to odd-numbered chirps 901, 903, and 905 before transmission. However, for even-numbered chirps 902, 904, and 906 (e.g., the 2nd, 4th, nth, etc.), the ramp signal is modified by the phase shifter to a desired value (ΔΦ) of phase shift for transmission. setting This induces a phase shift (ΔΦ). In this way, the non-phase-shifted chirp is interleaved with the phase-shifted chirp. The desired value of the phase shift is obtained. setting ) is the value to be calibrated. In the alternative example, odd-numbered chirps 901, 903, and 905 may be transmitted as phase-shifted chirps, while even-numbered chirps 902, 904, and 906 may be transmitted without phase shifting.

[0036] Technique 800 determines that the actual phase difference between the transmitted odd and even chirps 901-906 is the desired phase shift value (ΔΦ). settingIt can be used to calibrate the phase shifter when it does not match the specified values. Each desired phase shift value used with a particular phase shifter may be calibrated separately, as the phase shifter may not have the same effect on each phase. However, the effect of the phase shifter on uncalibrated values ​​can be approximated by interpolation, which involves using a pair of calibrated values ​​to find the uncalibrated value between them.

[0037] Referring again to Figure 8, when the reflected signal is received from the reflected chirp, a digital IF signal is generated (804). The digital IF signal is divided (806) and grouped into separate subframes based on the signals belonging to the set of received signals from the unshifted chirps (e.g., odd-numbered chirps 901, 903, 905) and the set of received signals from the shifted chirps (e.g., even-numbered chirps 902, 904, 906). Figure 10 illustrates matrices 1000 and 1002 created from the separated digital IF signals. Matrix 1000 contains odd-numbered chirps such as chirp 1, chirp 3, ..., chirp N-1, and matrix 1002 contains even-numbered chirps such as chirp 2, chirp 4, ..., chirp N.

[0038] Referring again to Figure 8, a range FFT is performed on the digital IF signals in each matrix 1000, 1002 (808) to generate a range array for each digital IF signal. Then, a Doppler FFT is performed on each odd or even range array (810) to generate a pair of range Doppler arrays. As shown in Figure 11, an odd-numbered Doppler FFT 1100, having peaks 1102, 1104, 1106, and 1108 referenced in various range Doppler cells, is generated based on the odd-numbered chirp matrix 1000, and an even-numbered Doppler FFT 1110, having peaks 1112, 1114, 1116, and 1118 referenced in various range Doppler cells, is generated based on the even-numbered matrix 1002.

[0039] Referring to Figures 8 and 11, a detection algorithm is performed to identify the detected objects in the 2D-FFT matrices 1100 and 1110 (812). Object identification involves converting the complex 2D-FFT matrices 1100 and 1110 into real positive numbers by taking the absolute values ​​of the matrix elements. Then, a detection algorithm, such as constant false alarm rate (CRAR) detection, is performed on the resulting matrices to identify peaks 1102 and 1112. Peaks 1102 and 1112 are then identified as detected objects. In some examples, the sum of the absolute values ​​of corresponding elements of the 2D-FFT matrices across the receiving antenna is calculated, and the resulting matrix is ​​then used to identify the detected objects. It is also possible to sum the absolute values ​​of corresponding elements of a pair of 2D-FFT matrices (corresponding to odd and even chirps of a particular receiving antenna) and use this for detection.

[0040] Once cells in the 2D-FFT matrices 1100, 1110 corresponding to the detected object are identified, technique 800 compares the corresponding phases of the range Doppler cells between the two 2D-FFT matrices 1100, 1110 (814). For the i-th detected object, the difference or shift between the phases of the corresponding cell pairs (from each 2D-FFT 1100, 1110 at the same range index and Doppler index) is ΔΦ. i The movement of an object during the application of one chirp pulse or between the application of one chirp pulse and a subsequent chirp pulse induces a velocity-induced phase shift, independent of the phase shift induced by the phase shifter simply because the object moved between chirps. For objects in a Doppler cell with non-zero rows, the phase can be corrected to compensate for the velocity-induced phase shift (816). This correction is calculated as follows: TIFF0007835380000001.tif520 Here, N doppler k is the length of the Doppler dimension of the 2D-FFT matrices 1100 and 1110, and k doppler_bin ΔΦ is the Doppler index of the range-Doppler cell corresponding to the target.i For, the corrected value is ΔΦ i,corr and is expressed as

[0041] FIG. 12 illustrates an indexing scheme 1200 for Doppler index (k Doppler_bin ) for a 2D-FFT 1202 having odd rows 1204. As shown, the first row 1206 (k doppler_bin = 0) is arranged as the central vertical row. Rows above the zero Doppler row 1206, such as rows 1208 and 1210, correspond to positive Doppler (k Doppler_bin > 0), while rows below the zero Doppler row 1206, such as rows 1212 and 1214, correspond to negative Doppler (k Doppler_bin < 0).

[0042] FIG. 13 illustrates an indexing scheme 1300 for Doppler index (k Doppler_bin ) for a 2D-FFT 1302 having even rows 1304. As shown, since the matrix 1302 has even rows 1304, the row 1304 is not the central row. In this case, the first row 1306 corresponding to the top row of the lower half of the row 1304 is arranged as the central vertical row (k doppler_bin = 0). Rows above the zero Doppler row 1306, such as rows 1308 and 1310, correspond to positive Doppler (k Doppler_bin > 0), while rows below the zero Doppler row 1306, such as rows 1312 and 1314, correspond to negative Doppler (k Doppler_bin < 0).

[0043] Referring again to FIG. 8, in some examples, an outlier detection algorithm is implemented (818) to detect and remove outliers within the set {ΔΦ 1、corr, ΔΦ 2、corr, ΔΦ 3,corr、...}. For example, outliers can be identified by their signal-to-noise ratio, by an estimate that the outliers are outside the range of expected values, etc. The average of all identified phase differences (whether outliers have been removed or not) is calculated as follows (820). TIFF0007835380000002.tif520 Here, ΣΔΦ i,corr This is the sum of all corrected values, N objects This is the number of corrected values.

[0044] ΔΦ ave is ΔΦ setting Represents an estimate of the true or actual phase shift applied to the intended setting. ΔΦ ave Value and ΔΦ setting If the difference between (822) and is outside the desired tolerance range, technique 800 returns, in one example, to the transmission step 802, and the modified ΔΦ setting You can retry with a value. For example, ΔΦ ave If it is determined that too large a phase shift is being inserted into the signal, then ΔΦ setting The value of ΔΦ can be reduced by the difference of the extra phase shift and processed through the process of technique 800 for another iteration. ave Until ΔΦ falls within the desired tolerance range, setting It is possible to repeatedly modify it.

[0045] ΔΦ ave and ΔΦ setting Both can be stored in computer-readable memory such as a lookup table (824). In this way, the lookup table is stored in the applied phase shift ΔΦ ave Along with the phase shifter setting ΔΦ setting It is created by listing the following. Technique 800 is ΔΦ setting This can be repeated for other values ​​of . Such lookup tables do not need to be exhaustive and can be configured to include only phase shifts near the phase shift that should be applied to a particular application (for example, implementing a transmit multiplexing scheme like DDMA would include a specific set of phase shifts). Each application then searches the table and finds the ΔΦ closest to the desired setting. ave Identify entries having and set the phase shifter to the corresponding ΔΦ settingSet it to either or interpolate the value as described above. If multiple receiving antennas exist, technique 800 can be repeated for each pair of 2D-FFTs generated at each receiving antenna, and the estimated phase difference can be included in the average calculation.

[0046] Technique 800 can be used to calibrate the phase shifters 316 of radar systems 300 and 400 in the field, for example, after systems 300 and 400 have left their manufacturing facilities. Technique 800 can be set to be performed on a time-based schedule or manually. Furthermore, Technique 800 does not require the immobility of radar systems 300 and 400. Thus, calibration of the phase shifters 316 of radar systems 300 and 400 by performing Technique 800 can be achieved while radar systems 300 and 400 are in motion, for example, when installed in a moving vehicle. Creating separate 2D-FFTs based on whether the received signal corresponds to a phase-shifted chirp transmission or a non-phase-shifted chirp transmission, as described herein, is useful for generating 2D-FFTs in which the peaks detected in each 2D-FFT correspond to the same range-Doppler cell position. In the case of a stationary field of view, one set of chirps to which no phase shift is applied may be transmitted following a transmission of phase-shifted chirps, and vice versa, since the field of view does not change between signal transmission types. However, in the case of a moving field of view (e.g., a radar system, objects in the field of view, or both causing each other to change position), interleaving the chirp signals can reduce the resulting 2D-FFT field of view difference when one type of chirp transmission follows another type of chirp transmission in time.

[0047] The above description of various preferred embodiments of the present invention is presented for illustrative and explanatory purposes only. It is not exhaustive and does not limit the invention to the exact forms described, and it is evident that many modifications and variations are possible in light of the above teachings. The above embodiments have been selected and described to best illustrate the principles and practical applications of the present invention, thereby enabling other persons skilled in the art to best utilize the invention with various modifications in various embodiments to suit specific intended uses. The scope of the present invention is defined by the claims appended herein.

Claims

1. It is a radar system, A radar transceiver integrated circuit (IC), A chirp generator configured to generate a frame of a first chirp signal including a subset of a first chirp signal and a subset of a second chirp signal, A phase shifter coupled to the chirp generator, the phase shifter being configured to receive a frame of the first chirp signal and induce a phase shift in a subset of the first chirp signal, The radar transceiver IC includes, A processor coupled to the radar transceiver IC, The phase shifter is controlled to induce a target phase shift in a subset of the first chirp signal. Multiple digital signals are generated in response to receiving the reflected chirp signal of the frame of the first chirp signal. The plurality of digital signals are processed to generate first and second range Doppler arrays corresponding to subsets of the first and second chirp signals, respectively. One or more objects are identified in the first and second range Doppler arrays, and the identified one or more objects are represented in the corresponding cells of the first and second range Doppler arrays. For each of the one or more objects identified in the first and second range Doppler arrays, the phase of the object represented in the first range Doppler array is compared with the phase of the object represented in the second range Doppler array. Based on the above comparison, the actual phase shift in the subset of the first chirp signal caused by the target phase shift induced in the subset of the first chirp signal by the phase shifter is determined. The processor is configured as follows: A radar system, including one.

2. A radar system according to claim 1, A radar system in which the processor is further configured to control the phase shifter so as not to induce a phase shift in each of the chirp signals of the subset of the second chirp signals.

3. A radar system according to claim 1, A radar system in which the chirp signals of a subset of the first chirp signal are interleaved with the chirp signals of a subset of the second chirp signal.

4. A radar system according to claim 1, The aforementioned processor, A first matrix is ​​generated based on a subset of the first digital signals of the plurality of digital signals, corresponding to the reflections received based on the subset of the first chirp signal, A second matrix is ​​generated based on a subset of the second digital signals of the plurality of digital signals, corresponding to reflections received based on the subset of the second chirp signal. A radar system further configured in this way.

5. A radar system according to claim 4, The aforementioned processor, A range Fast Fourier Transform (FFT) is performed on each digital signal in the first matrix in order to generate a first range array. A range FFT is performed on each digital signal in the second matrix in order to generate a second range array for each digital signal in the second matrix. To generate the first range Doppler array, a Doppler FFT is performed on the columns of the first range array. To generate the second range Doppler array, a Doppler FFT is performed on the columns within the second range array. A radar system further configured in this way.

6. A radar system according to claim 5, The aforementioned processor, In each of the first and second range Doppler arrays, one or more peaks corresponding to each range Doppler cell and corresponding to one or more objects within the field of view of the radar system are identified. Each identifies one or more phase shifts corresponding to a phase shift between each of the one or more peaks in the first range Doppler array and the corresponding peak in the second range Doppler array, Based on the identified one or more phase shifts, the actual phase shifts in the subset of the first chirp signal are determined. A radar system further configured in this way.

7. A radar system according to claim 6, The processor is further configured to calculate the average phase shift of the identified one or more phase shifts, A radar system in which the processor configured to determine the actual phase shift in a subset of the first chirp signal is configured to determine the actual phase shift in a subset of the first chirp signal based on the average phase shift.

8. A radar system according to claim 6, A radar system in which the processor is further configured to store the determined actual phase shift in a subset of the first chirp signals in a computer-readable storage memory.

9. A radar system according to claim 6, The aforementioned processor, Determine whether the difference between the target phase shift and the actual phase shift determined is within the allowable range. If the above difference is not within the above tolerance value, Send the second chirp signal frame, In a subset of the first chirp signal in the frame of the second chirp signal, the phase shifter is controlled to induce a modified phase shift based on the determined actual phase shift in the subset of the first chirp signal. Based on the digital signal corresponding to the reflection received based on the frame of the second chirp signal, the phase shifter determines the repetitive phase shift caused by the modified phase shift induced in a subset of the first chirp signal in the frame of the second chirp signal. A radar system further configured in this way.

10. A radar system according to claim 7, A radar system in which the processor is further configured to remove outliers of the identified one or more phase shifts before calculating the average phase shift.

11. It is a method, To generate a frame of a first chirp signal that includes a subset of a first chirp signal and a subset of a second chirp signal, The phase shifter induces a target phase shift in a subset of the first chirp signal, The transmission of the first chirp signal frame described above begins, The process involves generating a plurality of digital signals in response to receiving the reflected chirp signal of the frame of the first chirp signal, Processing the plurality of digital signals to generate first and second range Doppler arrays corresponding to subsets of the first and second chirp signals, Identifying one or more objects in the first and second range Doppler arrays, wherein each of the identified one or more objects is represented in the corresponding cell of the first and second range Doppler arrays, For each of the one or more objects identified in the first and second range Doppler arrays, the phase of the object represented in the first range Doppler array is compared with the phase of the object represented in the second range Doppler array, Based on the results of the comparison, the actual phase shift in the subset of the first chirp signal caused by the target phase shift induced in the subset of the first chirp signal by the phase shifter is determined. Methods that include...

12. The method according to claim 11, A method wherein each chirp signal in the subset of the second chirp signal is not subject to the phase shift induced by the phase shifter.

13. A method according to claim 12, A method further comprising interleaving the chirp signals of a subset of the first chirp signals with the chirp signals of a subset of the second chirp signals.

14. A method according to claim 12, A first matrix is ​​generated based on a subset of the first digital signals of the plurality of digital signals, wherein the first matrix is ​​generated such that the subset of the first digital signals corresponds to a reflection received based on a subset of the first chirp signals. A second matrix is ​​generated based on a subset of the second digital signals of the plurality of digital signals, wherein the subset of the second digital signals corresponds to a reflection received based on a subset of the second chirp signals. Methods that further include the above.

15. The method according to claim 14, To generate a first range array for each digital signal in the first matrix, a range fast Fourier transform (FFT) is performed on each digital signal in the first matrix, To generate a second range array for each digital signal in the second matrix, a range fast Fourier transform (FFT) is performed on each digital signal in the second matrix, To generate the first range Doppler array, a Doppler FFT is performed on the columns within the first range array, To generate the second range Doppler array, a Doppler FFT is performed on the columns within the second range array, Methods that further include the above.

16. The method according to claim 15, The above identification is Identifying one or more peaks in each of the first and second range Doppler arrays, wherein the one or more peaks correspond to each range Doppler cell and to one or more objects in the field of view. Identifying one or more phase shifts, wherein each phase shift corresponds to a phase shift between each of the one or more peaks in the first range Doppler array and the corresponding peak in the second range Doppler array. Determining the actual phase shift in a subset of the first chirp signal in a frame of the first chirp signal based on the identified one or more phase shifts, Methods that include...

17. The method according to claim 16, The process further includes calculating the average phase shift of one or more identified phase shifts. A method for determining the actual phase shift in a subset of the first chirp signal of the frame of the first chirp signal, comprising determining the actual phase shift in a subset of the first chirp signal based on the average phase shift.

18. The method according to claim 16, A method further comprising storing the determined actual phase shift in a subset of the first chirp signal in a computer-readable storage memory.

19. The method according to claim 16, To determine whether the difference between the target phase shift and the determined actual phase shift is within an acceptable range, If the aforementioned difference is not within the acceptable range, Send the second chirp signal frame, Control the phase shifter in such a way that in a subset of the first chirp signal in the frame of the second chirp signal, the phase shifter is controlled to induce a modified phase shift based on the determined actual phase shift in the subset of the first chirp signal in the frame of the second chirp signal. Based on the digital signal corresponding to the reflection received based on the frame of the second chirp signal, the phase shifter determines the repetitive phase shift caused by the modified phase shift induced in a subset of the first chirp signal in the frame of the second chirp signal. That thing, Methods that further include the above.

20. The method according to claim 17, A method further comprising removing outliers of the identified one or more phase shifts before calculating the average phase shift.

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