Doppler division multiplexing (DDM) multiple-input multiple-output (MIMO) radar system and decoding method

Abstract

A radar system may include a transmitter module configured to transmit a plurality of transmit signals according to a Doppler domain multiplexing (DDM) scheme; a receiver module configured to receive reflections from the plurality of transmit signals reflected from an object and generate corresponding digital signals; and a signal processor configured to generate a distance-Doppler antenna cube representative of the digital signal, and for each of the distance bins of the cube, a decoded range-Doppler bitmap (RDBM) is generated from the range-Doppler antenna cube by generating a decoded RDBM row by: extracting a range bin matrix; performing a discrete Fourier transform on the distance bin matrix to generate an output matrix; determining a peak value position in the output matrix; comparing associated peak locations of transmit channels across the output matrix to identify location matching peaks associated with the Doppler bins; and generating a decoded RDBM row based on the position matching peak.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority under 35 USC §119 to Romanian patent application number a202300438 filed on August 9, 2023, the contents of which are incorporated herein by reference. Technical Field

[0003] Embodiments of the subject matter described herein generally relate to radar systems, including Doppler division multiplexing (DDM) multiple-input multiple-output (MIMO) radar systems, and associated decoding techniques. Background Art

[0004] Radar systems can be used to detect the distance, speed, and angle of nearby objects. With the advancement of technology, radar systems can now be applied to many different applications, such as automotive radar safety systems, which increasingly use radar systems to detect changes in the surrounding environment, such as approaching another car for blind spot detection or detecting leading vehicles for improved cruise control. Accurate radar detection is also an integral part of autonomous vehicle control systems. However, there are challenges in accurately detecting the position and movement of objects using radar systems that can be built on cars. A common method to improve the angular resolution of automotive radar systems uses multiple transmit antennas and receive antennas to implement a multiple-input multiple-output (MIMO) automotive radar system. In a MIMO radar system, the virtual array consists of multiple array elements, which are equal to the product of multiple transmit antennas and receive antennas. Compared with a single transmitter system, the increased aperture of a MIMO radar improves the ability to separate these objects based on the angle of arrival (AoA) of the signal reflected by the object. Summary of the invention

[0005] A brief overview of various exemplary embodiments is presented below. Some simplifications and omissions may be made in the following overview, which is intended to highlight and introduce some aspects of the various exemplary embodiments without limiting the scope. A detailed description of the exemplary embodiments sufficient to allow a person of ordinary skill in the art to obtain and use these concepts will be presented in subsequent sections.

[0006] In an example embodiment, a radar system may include: a transmitter module configured to transmit a plurality of transmit signals according to a Doppler domain multiplexing (DDM) scheme; a receiver module configured to receive reflections of the plurality of transmit signals reflected by at least one object and generate a digital signal with the received reflections; and a signal processor. The signal processor may be configured to generate a range-Doppler antenna cube representing the digital signal, the range-Doppler antenna cube comprising at least a plurality of range bins and a plurality of Doppler bins. The signal processor may be configured to: for each of the plurality of range bins of the range-Doppler antenna cube: extract a range bin matrix from the range-Doppler antenna cube; perform a discrete Fourier transform (DFT) on each range-Doppler cell of the range bin matrix in a channel dimension to generate an output matrix; determine a peak position in the output matrix; for each Doppler bin, compare the associated peak positions across all transmit channels represented in the output matrix to identify a position matching peak associated with the Doppler bin; and generate a decoded RDBM row based on the position matching peak. The signal processor may be configured to generate a decoded RDBM based on the decoded RDBM rows.

[0007] In one or more embodiments, the signal processor for generating decoded RDBM rows may be further configured to generate, for each of the Doppler bins of the output matrix, a binary value indicating whether the number of position matching peaks associated with the Doppler bin exceeds a predetermined threshold.

[0008] In one or more embodiments, the signal processor for determining the peak position of the output matrix can be further configured to: determine a maximum value for each of the specific Doppler bins of the output matrix; compare the cell value of the specific Doppler bin with the determined maximum value; in response to a first cell of the specific Doppler bin having a value greater than or equal to the determined maximum value, update the cell value of the first cell to be equal to a predetermined value; and in response to a second cell of the specific Doppler bin having a value less than the determined maximum value, update the cell value of the second cell to be equal to zero. The signal processor can be further configured to generate a first matrix based on the updated cell value of each specific Doppler bin of the output matrix.

[0009] In one or more embodiments, the signal processor for comparing associated peak positions is additionally configured to generate a second matrix comprising groups of Doppler bins. Each group of Doppler bins may comprise a column of the first matrix representing each of the transmit channels.

[0010] In one or more embodiments, each set of columns of the second matrix adjusted for a transmit channel offset in the Doppler dimension corresponds to the same unambiguous velocity. The transmit channel offset is defined according to an associated DDM code.

[0011] In one or more embodiments, the signal processor for generating the decoded RDBM row is further configured to generate a third matrix by calculating the scalar product of the cells in each row of each group of the second matrix. The result of the scalar product for a given group of the second matrix can form a corresponding column of the third matrix.

[0012] In one or more embodiments, the signal processor for generating the third matrix is ​​further configured to convert the coefficients 1 / N ch Applied to the result of each scalar product, where N ch is the number of transmit channels represented in the range-Doppler antenna cube.

[0013] In one or more embodiments, the signal processor for generating decoded RDBM rows is further configured to generate a fourth matrix by applying a threshold to each cell of the third matrix, such that cells of the third matrix having values ​​greater than the threshold are set to 1 in the fourth matrix, and cells of the third matrix having values ​​less than the threshold are set to 0 in the fourth matrix.

[0014] In one or more embodiments, the threshold is equal to a predetermined value. In one or more other embodiments, the threshold is less than a predetermined value.

[0015] In one or more embodiments, the signal processor for generating the decoded RDBM row is configured to generate the decoded RDBM row as an array of maximum values ​​per column of the fourth matrix.

[0016] In an example embodiment, a method includes the steps of generating, by a signal processor of a radar system, a range-Doppler antenna cube, the range-Doppler antenna cube representing a digital signal corresponding to a signal reflected by an object, the range-Doppler antenna cube including at least a plurality of range bins and a plurality of Doppler bins; and generating, by the signal processor, a decoded range-Doppler bitmap (RDBM). Generating the decoded RDBM may include the steps of: for each of a plurality of range bins of the range-Doppler antenna cube: extracting a range bin matrix from the range-Doppler antenna cube; performing a discrete Fourier transform on each range-Doppler cell of the range-Doppler antenna cube to generate an output matrix; determining a peak position in each Doppler bin of the output matrix; for each of the Doppler bins of the output matrix, comparing the associated peak positions on all transmit channels represented in the output matrix to identify a position matching peak associated with the Doppler bin; generating a decoded RDBM row based on the position matching peak in each Doppler bin; and combining the decoded RDBM rows to generate a decoded RDBM.

[0017] In one or more embodiments, generating the decoded RDBM row further includes generating, for each of the Doppler bins of the output matrix, a binary value indicating whether the number of position matching peaks associated with the Doppler bin exceeds a predetermined threshold.

[0018] In one or more embodiments, determining a peak position in each Doppler bin of an output matrix includes: for each specific Doppler bin of the output matrix, determining a maximum value of the specific Doppler bin; comparing a cell value of the specific Doppler bin with the determined maximum value; in response to a first cell of the specific Doppler bin having a value greater than or equal to the determined maximum value, updating the cell value of the first cell to be equal to a predetermined value; and in response to a second cell of the specific Doppler bin having a value less than the determined maximum value, updating the cell value of the second cell to be equal to a predetermined value; and generating a first matrix based on the updated cell values ​​of each specific Doppler bin of the output matrix.

[0019] In one or more embodiments, comparing the associated peak positions further comprises generating a second matrix comprising groups of columns of the first matrix. Each group of columns adjusted for a transmit channel offset in the Doppler dimension may correspond to the same unambiguous velocity. The transmit channel offset may be defined according to an associated DDM code.

[0020] In one or more embodiments, generating the decoded RDBM row further includes generating a third matrix by calculating a scalar product of the cells in each row of each group of the second matrix. The result of the scalar product for a given group of the second matrix can form a corresponding column of the third matrix. Generating the decoded RDBM row further includes converting the coefficients 1 / N ch Applied to the result of each scalar product, where N ch is the number of transmit channels represented in the range-Doppler antenna cube.

[0021] In one or more embodiments, generating the decoded RDBM row further includes generating a fourth matrix by applying a threshold to each cell of the third matrix, such that cells of the third matrix having values ​​greater than the threshold are set to 1 in the fourth matrix, and cells of the third matrix having values ​​less than the threshold are set to 0 in the fourth matrix.

[0022] In one or more embodiments, the threshold is equal to a predetermined value. In one or more other embodiments, the threshold is less than a predetermined value.

[0023] In one or more embodiments, generating the decoded RDBM row additionally includes generating the decoded RDBM row as an array of maximum values ​​per column of the fourth matrix. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] A more complete understanding of the subject matter may be obtained by reference to the detailed description and claims considered in conjunction with the following figures, wherein like reference numerals refer to similar elements throughout the figures. The elements in the figures are shown for simplicity and clarity and are not necessarily drawn to scale. The drawings, together with the detailed description, are incorporated into and form part of this specification and are used to further illustrate examples, embodiments, etc., and to explain various principles and advantages according to the present disclosure, wherein:

[0025] Figure 1 is a block diagram illustrating an example radar system according to one or more embodiments;

[0026] Figure 2 is a timing diagram illustrating a linear chirp transmission schedule for a Doppler division multiplexing (DDM) multiple-input multiple-output (MIMO) radar system in accordance with one or more embodiments.

[0027] Figure 3 is a graph showing radian frequency Doppler shift and signal amplitude of detected reflections corresponding to four chirps simultaneously transmitted by four different transmitters, respectively, according to one or more embodiments;

[0028] Figure 4 is a process flow diagram describing a method of object tracking according to one or more embodiments, wherein the method may be implemented by a radar system, such as Figure 1 The radar system is performed, the method comprising performing DDM decoding after range compression and Doppler compression of raw data samples;

[0029] Figure 5 is a diagram illustrating an input range-Doppler antenna cube and a decoded range-Doppler bitmap (RDBM) generated based on the input range-Doppler antenna cube according to one or more embodiments;

[0030] Figure 6 is a diagram illustrating a process by which a decoded RDBM may be generated based on an input range-Doppler antenna cube, including intermediate matrices and mappings and corresponding process steps, according to one or more embodiments;

[0031] Figure 7 is a process flow diagram describing a method of generating a decoded RDBM according to one or more embodiments, wherein the method may be used by a radar system, such as Figure 1 The radar system performs and can be used as an object tracking method, such as Figure 4 Execute as part of the method;

[0032] Figure 8is a process flow diagram describing a method for generating a decoded RDBM based on the position of a maximum value for each range bin in a MAX map generated based on an output of a discrete Fourier transform (DFT) or a fast Fourier transform (FFT) according to one or more embodiments, wherein the method may be used by a radar system, e.g. Figure 1 The radar system performs and can be used as an object tracking method, such as Figure 4 Execute as part of the method;

[0033] Fig. 9 is an illustration of a method for transmitting a signal according to a linear chirp transmission schedule (eg, Figure 2 a graph of a coherently integrated range-Doppler map (RDM) corresponding to reflections of simultaneously transmitted chirps (a linear chirp transmission schedule); and

[0034] Fig.10 is an illustration according to one or more embodiments Fig. 9 The coherent integration of the RDM corresponds to and according to e.g. Figure 7 method or Figure 8 The decoding method generates a graph of the decoded RDBM. DETAILED DESCRIPTION

[0035] The following detailed description is merely illustrative in nature and is not intended to limit the embodiments of the subject matter or the application and uses of such embodiments. In addition, it is not intended to be bound by any explicit or implicit theory present in the foregoing technical field, background technology or the following detailed description.

[0036] For simplicity and clarity of illustration, the drawings illustrate general construction methods, and descriptions and details of well-known features and techniques may be omitted for brevity. In addition, the elements in the drawings are not necessarily drawn to scale. For example, the dimensions of some elements or regions in the drawings may be enlarged relative to other elements or regions to help improve the understanding of the embodiments described herein.

[0037] The terms "first", "second", "third", "fourth", etc. (if any) in the embodiments and claims can be used to distinguish similar elements, and are not necessarily used to describe a specific sequence or time order. It should be understood that the terms used in this way are interchangeable where appropriate, so that the embodiments described herein can, for example, operate in a sequence different from that shown or otherwise described herein. In addition, the terms "including", "having" and any variations thereof are intended to cover non-exclusive inclusions, so that the process, method, object or device including a series of elements is not necessarily limited to those elements, but may include other elements that are not explicitly listed or inherent to such processes, methods, objects or devices. The term "coupled" as used herein is defined as being connected directly or indirectly in an electrical or non-electrical manner. As used herein, the terms "substantially" and "substantially" mean sufficient to achieve the stated purpose in a practical manner, and minor defects (if any) are not significant for the stated purpose. As used herein, the words "exemplary" and "example" mean "serving as an example, instance or illustration". Any embodiment described herein as exemplary or example should not necessarily be interpreted as being preferred or advantageous over other embodiments.

[0038] Unless otherwise stated, directional references such as "top", "bottom", "left", "right", "above", "below", etc. are not intended to require any preferred orientation, but are described for illustrative purposes with reference to the orientation of the corresponding figure or figures.

[0039] For the sake of brevity, conventional semiconductor manufacturing techniques may not be described in detail herein. In addition, certain terms may also be used herein for reference only and are therefore not intended to be limiting. For example, the terms "first," "second," and other such numerical terms referring to structures do not imply a sequence or order unless the context clearly indicates otherwise.

[0040] Various embodiments described herein relate to a Doppler division multiplexing (DDM) multiple-input multiple-output (MIMO) radar system with integrated object tracking capability, the radar system using a decoding technique that utilizes angle of arrival (AoA) information. Conventional decoding solutions for DDM MIMO radar systems rely on constant false alarm rate (CFAR) detection and do not utilize AoA information. The DDM decoding technique described herein uses spatial information as a decoding parameter and does not require conventional simple threshold comparison or peak detection steps. The speed at which DDM decoding can be performed using an embodiment of the DDM decoding technique described herein can be advantageously improved compared to the speed of conventional decoding techniques that rely on, for example, CFAR detection. In addition, due at least in part to the omission of conventional peak detection and threshold detection-based techniques, an embodiment of the DDM decoding technique described herein may be less susceptible to phase noise than conventional techniques.

[0041] One or more embodiments of the DDM decoding techniques described herein have an analytical closed-form solution for the false alarm probability. Furthermore, the statistical application of spatial information in the DDM decoding techniques of the present invention may result in a relatively low false alarm probability compared to conventional decoding and detection techniques.

[0042] In one or more embodiments, a radar system includes a microcontroller unit (MCU) having a signal processor configured to generate a range-Doppler antenna cube from, for example, raw ADC samples derived from return signals (i.e., reflections) corresponding to reflections of a transmit signal (e.g., chirp) transmitted via a transmitter (TX) antenna element of the radar system (e.g., according to a Doppler segmentation scheme having, for example, a uniform pulse repetition interval (PRI)), wherein the return signal is received via a receiver (RX) antenna element of the radar system. For example, the range-Doppler antenna cube can be generated by performing range compression (e.g., in the form of a fast-time Fast Fourier Transform (FFT)) and Doppler compression (e.g., in the form of a slow-time FFT) on raw ADC samples output by one or more ADCs of a receiver module of the radar system. The signal processor can then perform per-channel angle of arrival (AoA) estimation by performing a channel dimension FFT on each range-Doppler cell of the range-Doppler antenna cube to generate a corresponding FFT output matrix for each range bin. The signal processor may then perform DDM decoding based on the FFT output matrix to generate a decoded range-Doppler bitmap (RDBM), wherein each row of the RDBM corresponds to a respective FFT output matrix of the FFT output matrix, and therefore corresponds to a respective range bin of the range-Doppler antenna cube. Although one or more embodiments described herein relate to the use of FFT, it should be understood that this is intended to be illustrative and not limiting. According to one or more other embodiments, other suitable techniques for performing a discrete Fourier transform (DFT) may be used instead.

[0043] Standard DDM MIMO technology implies having all transmitters active in the same time frame, with each transmitter having a respectively different self-induced chirp-to-chirp phase rotation, while maintaining a common and constant pulse repetition frequency (PRF). This results in a signal sequence being transmitted from each transmitter module that is orthogonal in the Doppler domain, so that the return signal received from each target is replicated in the Doppler domain at different speeds, depending on the transmitter module (or TX channel) associated with the return signal. These replicas depend on the DDM code, and the order of the replicas needs to be known in order to correctly construct the MIMO array. Finding the order of such replicas is considered "decoding" in this article, which is equivalent to Find the unambiguous speed of the target within the unambiguous Doppler range, where TR is the pulse repetition interval (PRI).

[0044] The DDM decoding process may include generating a decoded RDBM row for each range bin of the input range-Doppler antenna cube by: generating a maximum value array for each column (i.e., Doppler bin) of the FFT output matrix corresponding to the range bin; generating a "MAX" map based on the FFT output matrix and the maximum value array; generating an aligned MAX map of column groups (i.e., Doppler bin data) including MAX maps, each group including a corresponding column for each TX channel represented in the FFT output matrix and corresponding to a corresponding Doppler bin of the FFT output matrix; generating a combined MAX map based on the average maximum value per angle bin of each group; generating a filtered MAX map by applying a threshold to all elements of the combined MAX map; and generating a decoded RDBM row based on the filtered MAX map. The signal processor may then output a decoded RDBM formed by the generated decoded RDBM rows. The decoded RDBM may, for example, include a two-dimensional (2D) array of ones and zeros, wherein the width of the decoded RDBM is equal to the number of chirps transmitted by each TX channel during the time period being processed. In one or more embodiments, the thresholds that the signal processor applies to the combined MAX map to generate the filtered MAX map may be adjusted to change the number of TX channels that need to be aligned in order to be interpreted as corresponding to a detected target object.

[0045] In one or more embodiments, the tolerance for the identified maximum values ​​in two TX channels within a given group to be designated as "aligned" may be widened to reduce the likelihood of false negatives. For example, the signal processor may be configured with a wider tolerance such that if the identified maximum values ​​of two TX channels in a given Doppler bin are placed in the same or adjacent angular bins (i.e., rather than being limited to the same angular bin), they may be considered aligned.

[0046] Figure 1A block diagram of a linear chirp DDM MIMO automotive radar system 100 is shown, which includes a DDM MIMO radar device 102 connected to a radar microcontroller unit (MCU) 104. In one or more embodiments, the device 102 can be a linear frequency modulation (LFM) DDM MIMO radar device. In one or more embodiments, the DDM MIMO radar device 102 can be embodied as a field replaceable unit (LRU) or a modular component designed to be quickly replaced in an operating position. Similarly, the radar MCU 104 can be embodied as a field replaceable unit (LRU) or a modular component. Although a single or monostatic DDM MIMO radar device 102 is shown, it should be understood that additional distributed radar devices can be used to form a distributed or multi-static radar. In addition, the depicted radar system 100 can be implemented in the form of an integrated circuit, wherein the DDM MIMO radar device 102 and the radar MCU 104 are formed by separate integrated circuits (chips) or by a single chip, depending on the application.

[0047] Radar device 102 includes one or more transmit antenna elements 126 (sometimes referred to herein as “transmit antenna 126”) and receive antenna elements 142 (sometimes referred to herein as “receive antenna 142”), which are connected to one or more radio frequency (RF) transmitter (TX) modules 118 and receiver (RX) modules 128, respectively. Each transmit antenna 126 and TX module can be connected to a plurality of transmit antenna elements 126, ... i , where "i" is the total number of transmit (TX) channels. Each receive antenna 142 and RX module 128 may be associated with a corresponding transmit channel in a set of transmit channels of RX1, RX2, RX3, ... RX j, where “j” is the number of receive (RX) channels. As a non-limiting example, a radar device (e.g., radar device 102) may include respective antenna elements (e.g., antenna elements 126) connected to four transmitter modules (e.g., transmitter modules 118) and sixteen receiver modules (e.g., receiver modules 128), respectively. These numbers of transmitter and receiver antenna elements and modules are intended to be illustrative and non-limiting, wherein other numbers of these elements are possible in one or more other embodiments, such as four transmitter modules 118 and six receiver modules 128, or a single transmitter module 118 and / or a single receiver module 128. Radar device 102 includes a chirp generator 116 that is configured to supply a chirp input signal to transmitter module 118. To this end, the chirp generator 116 is configured to receive input program and control signals from the MCU 104 via the digital-to-analog converter 114, which, as a non-limiting example, include a reference local oscillator (LO) signal, a chirp start trigger signal, and a program control signal. The chirp generator 116 is configured to generate a chirp signal and send the chirp signal to the transmitter module 118 for transmission via the transmit antenna element 126. In one or more embodiments, each transmitter module includes a phase rotator 120 (sometimes referred to herein as a "phase shifter 120") configured to apply phase decoding to the chirp signal, wherein the phase rotator 120 is controlled by the program control signal generated by the MCU 104. In one or more embodiments, the phase rotator 120 can provide uniform phase shifts between the transmitter modules 118. According to one or more other embodiments, the phase rotator 120 can alternatively provide each transmitter module 118 with the ability to implement a progressive phase shift using a non-uniform decoding technique. Each transmitter module 118 includes an RF conditioning module 122 configured to filter the phase-coded chirp signal. Each transmitter module 118 includes a power amplifier 124 configured to amplify the filtered phase-coded chirp signal before it is provided to and transmitted via one or more corresponding transmit antenna elements 126. By using each transmit antenna 126 to transmit a sequence of progressive phase shifts of the chirp signal, each transmitter module 118 operates in a Doppler division multiplexing manner with other transmitter modules of the transmitter modules 118 because the transmitter modules are programmed to transmit the same waveform simultaneously on a phase-separated schedule. Herein, the transmitted chirp signal is sometimes referred to as a "transmit signal".

[0048] The radar signal transmitted by the transmitter antenna module 118 may be reflected by objects in the environment of the radar device 102, and a portion of the reflected radar signal, sometimes referred to herein as a "return signal" or "reflection", is received by the receiver antenna module 128 at the radar device 102. At each receiver module 128, the received (RF) antenna signal is amplified by a low noise amplifier (LNA) 140 and then fed to a mixer 138, where the received (RF) antenna signal is mixed with the transmitted chirp signal generated by the RF conditioning module 122. The resulting intermediate frequency signal is fed to a high pass filter (HPF) 136. The resulting filtered signal is fed to a variable gain amplifier 134, which amplifies the filtered signal before feeding it to a low pass filter (LPF) 132. This re-filtered signal is fed to an analog-to-digital converter (ADC) 130 and output by each receiver module 128 as a digital signal (e.g., to the signal processor 110 of the MCU 104). In this manner, the receiver module 128 compresses the various delayed target echoes into a plurality of sinusoidal tones whose frequencies correspond to the round-trip delays of the echoes.

[0049] In the radar system 100, the radar MCU 104 may be connected and configured to supply input control signals to the radar device 102 and receive digital output signals generated by the receiver module 128 therefrom. In one or more embodiments, the radar MCU 104 includes a radar controller 108 and a signal processor 110, wherein either or both of the radar controller 108 and the signal processor 110 may be embodied as a microcontroller unit (MCU) or other processing unit. The radar controller 108 may receive data from the radar device 102 (e.g., from the receiver module 128) and may control radar parameters of the radar device 102 via a DAC 114, such as the frequency band, length, etc. of each radar frame. For example, the DAC 114 may be used to adjust the radar chirp signal output from the chirp generator 116 included in the radar device 102. The signal processor 110 may be configured and arranged for signal processing tasks, such as, but not limited to, target object identification, calculating the spacing or distance to the target object, calculating the radial velocity of the target object, and calculating the AoA of the signal reflected by the target object. As used herein, the term “AoA” or “angle of arrival” refers to the angle of a signal (eg, radar signal) reflected by an object in the environment. Signal processor 110 may provide calculated values ​​associated with such calculations to storage device 112 and / or other systems via interface 106 .

[0050] As non-limiting examples, the interface 106 can enable the MCU 104 to communicate with other systems via local and wide area networks, the Internet, a car communication bus, and / or other types of wired or wireless communication systems. In one or more embodiments, the MCU 104 can provide calculated values ​​to other systems, such as a radar-camera-lidar fusion system; an automated driving assistance system including parking, braking, or lane change assistance features; and the like, through the interface 106. The storage device 112 can be used to store instructions for the MCU 104, data received from the radar device 102, calculated values ​​from the signal processor 110, and the like. The storage device 112 can be any suitable storage medium, such as a volatile or non-volatile memory.

[0051] To control the transmitter module 118, the radar controller 108 may, for example, be configured to generate transmitter input signals, such as programs, control triggers, reference LO signals, calibration signals, spectrum shaping signals (e.g., ramp generation in the case of an FMCW radar). The radar controller may, for example, be configured to receive data signals, sensor signals, and / or register programming or state machine signals for an RF (radio frequency) circuit enable sequence. In one or more embodiments, the radar controller 108 may be configured to program the transmitter module 118 with the transmitter input signals to operate in a DDM manner by progressively phase shifting the LFM chirp to be transmitted by the transmit antenna element 126. In a selected embodiment, the radar controller 108 is configured to progressively phase shift the LFM chirp output by the chirp generator 116 using coprime coding (CPC) encoding by programming the programmable phase rotator 120 before transmission. Each transmitter module 118 transmits a transmit channel signal having a different CPC-coded LFM signal generated using a programmable slow time phase rotator 120 so that the receiver module 128 can adjust the target object return signal (i.e., a return signal corresponding to a reflection of the transmit signal transmitted via the transmit antenna element 126 and reflected from one or more target objects, where the return signal is then received via the receive antenna element 142) to generate a digital domain signal, which is processed by the radar MCU 104 to separate and identify the CPC-coded transmit channel signals.

[0052] At each receiver module 128, a digital output signal is generated from the target return signal for digital processing by the signal processor 110 to construct and accumulate a multiple-input multiple-output (MIMO) array vector output to form a MIMO aperture for calculating AoA estimates and plots or maps of target object trajectories. Specifically, in the signal processor 110, the digital output signal can be processed by one or more fast Fourier transform (FFT) modules or discrete Fourier transform (DFT) modules, such as a fast time (range) FFT module that generates a range chirp antenna cube (RCAC) and a slow time (Doppler) FFT module that generates a range-Doppler antenna cube. The per-channel AoA estimation module of the signal processor 110 can then perform a corresponding channel dimension FFT on each range bin of the range-Doppler antenna cube to produce a plurality of FFT or DFT output matrices (i.e., one for each range bin of the range-Doppler antenna cube). The DDM decoder module of the signal processor 110 can then generate a decoded range-Doppler bitmap (RDBM) based on the FFT or DFT output matrix, as will be described in more detail below. The decoded RDBM can be further processed by the signal processor 110 to construct a DDM MIMO array vector, which the signal processor 110 then processes to perform AoA estimation and target object tracking. The MCU 104 can then output the resulting target trajectory (e.g., via the interface 106) to other automotive computing or user interface devices for further processing or display.

[0053] In order to Figure 1 For contextual understanding of the operation of the DDM MIMO radar system of the radar system 100, reference is now made to Figure 2 , which shows a timing diagram 200 showing four transmitters (eg, each transmitter corresponding to a respective one of the transmitters in one or more embodiments) using a uniform Doppler segmentation scheme. Figure 1 The radar module 118 and the transmit antenna element 126 of the transmitter module 118 are linear chirp transmission schedules 201, 202, 203, 204. Each transmitter is associated with a corresponding transmit channel in the transmit channels TX1-TX4 and is programmed to simultaneously transmit a DDM linear chirp waveform sequence in a single radar transmission frame. Each transmitter transmits a linear chirp waveform (e.g., 201A, 201B) at a fixed and uniform pulse repetition frequency (PRF) rate, which is the inverse of the pulse repetition interval (e.g., PRF=PRF). -1 ) or the inverse of the chirp interval (e.g., PRF = CIT -1). In addition, each transmitter encodes each chirp with an additional progressive phase offset by using a phase rotator in the front-end circuit. As a result of the progressive phase offset decoding, each of the received chirps corresponding to the reflections of the radar signal originating from each different transmitter effectively has a different zero radial velocity Doppler shift, and individual target detections can be associated with the corresponding transmitter from which the reflected radar signal originated, which is necessary for the correct operation of the subsequent MIMO virtual array construction.

[0054] The position of zero radial velocity is controlled by a progressive phase shift of the chirp applied to each transmitter based on the following equation:

[0055]

[0056] where f zrv,i is the zero radial velocity Doppler shift frequency of transmitter i, and where Ai is the incremental phase shift (radians) between two adjacent chirps. For example, in a 4-TX DDM MIMO radar system, each transmitter may be assigned the following incremental phase offset, and thus the zero radial velocity frequency:

[0057] TX1:A1=0→f zrv,1 =0[Hz];

[0058]

[0059] In this example, this result is depicted as follows: a first transmitter for transmit channel TX1 encodes its chirp waveform with a progressive phase offset of 0 degrees; a second transmitter for transmit channel TX2 encodes its chirp waveform with a progressive phase offset of 90 degrees; a third transmitter for transmit channel TX3 encodes its chirp waveform 20 with a progressive phase offset of 180 degrees; and a fourth transmitter for transmit channel TX4 encodes its chirp waveform with a progressive phase offset of 270 degrees. In a DDM MIMO radar system using uniform Doppler segmentation, a target can be unambiguously associated with the correct transmitter and TX channel by determining its location within the sectorized Doppler spectrum, provided that the target has a PRF of ± PRF / (2N before applying DDM). ch ) within the actual Doppler shift, where N ch is the number of DDM transmitter channels.

[0060] To illustrate the principle of Doppler peak detection and transmitter association, we now refer to Figure 3 , which depicts a graph of the Doppler spectrum as the radian frequency (and Doppler shift) of a uniform DDM-MIMO radar system varies (e.g., Figure 1) wherein the maximum radial velocity of a target does not exceed the allocated spectrum budget, thereby producing an unambiguous association of a target peak and a transmit antenna. As depicted, each transmitter channel TX1-TX4 has an allocated spectrum segment 311, 312, 313, 314 effectively centered at a corresponding zero radial velocity frequency (e.g., 0, π / 2, π, and 3π / 2). Thus, the zero radial velocity frequency of each transmitter channel TX1-TX4 is ±PRF / (2N ch ) can be unambiguously associated with the correct transmitter by determining its position within the sectorized Doppler spectrum 300. This result is true when the radial velocity of the target falls within the spectrum budget segments 311, 312, 313, 314 allocated for each transmitter channel TX1-TX4. As shown, the spectrum budget segments 311 for transmitter channel TX1 can be divided into segments 311A ​​that occur at the beginning of a time period and segments 311B that occur at the end of a time period.

[0061] In the case of existing 76-81 GHz fast chirp automotive radar front-end monolithic microwave integrated circuits (MMICs), the fastest chirp signal is limited by the chirp interval time (CIT) to no shorter than about 15 microseconds. Therefore, for such radar systems, the maximum unambiguous Doppler radial detectable velocity is ±65 m / s (or ±234 km / hr), and the entire range of detectable velocities is then divided into N ch N of the transmitters ch The invention relates to a method for supporting the transmission of radar signals by using a Doppler spectrum bandwidth of approximately 470 km / hr. The method can be used to support multiple segments and transmit channels for unambiguous DDM operation. In a high dynamic driving scenario where targets and radars are traveling at speeds of 100 km / hr or faster, the range of approximately 470 km / hr Doppler spectrum bandwidth is sufficient for only very few transmitters. While more transmitters and DDM transmitter channels can be supported without ambiguity by significantly shortening the CIT to microsecond periods, it should be noted that such ultra-short chirps provide additional cost and complexity to the radar system given such high dynamic driving conditions.

[0062] Figure 4 An illustrative process flow of a method 400 is shown by which raw data corresponding to sampled return signals are compared with transmitted signals (e.g., chirps transmitted according to a DDM scheme, such as Figure 2 According to one or more embodiments, the method 400 may be performed using either or both of a radar controller and a signal processor of a radar MCU. Figure 1The method 400 is described with reference to the elements of the radar system 100. However, it should be understood that this is illustrative and not limiting, at least because other suitable radar systems may be used to perform the method 400 in one or more other embodiments.

[0063] At block 402, the signal processor 110 of the MCU 104 of the radar system 100 receives raw sample data (sometimes referred to as "ADC samples") from one or more ADCs 130 of the receiver module 128. These ADC samples may be output by the ADC 130 as digital signals. These ADC samples represent the same signals as those transmitted by the transmitter module 118 via the transmit antenna element 126 (e.g., according to a DDM scheme, such as Figure 2 The radar system 100 includes a radar module 128 and a radar receiver module 128 that receives a received signal (sometimes referred to as a “reflected signal” or “returned signal”) corresponding to a reflection of a transmitted signal (i.e., a chirp) of the radar system 100, wherein the transmitted signal is reflected from one or more target objects in the environment of the radar system 100. The return signal is received by the receiver module 128 via the receive antenna element 142.

[0064] At block 404, the signal processor 110 performs range compression of the raw ADC samples, for example, by performing a fast time FFT or DFT on the raw ADC samples. The signal processor 110 may generate a range chirped antenna cube (RCAC) as an output of this fast time FFT or DFT.

[0065] At block 406, the signal processor 110 performs Doppler compression of the RCAC, for example, by performing a slow time FFT or DFT on the RCAC. The signal processor 110 may generate a range-Doppler antenna cube as an output of this slow time FFT or DFT. The range-Doppler antenna cube may be a three-dimensional array of dimensions m×n×p, where m represents the number of Doppler bins, n represents the number of range bins, and p represents the number of RX channels represented in the range-Doppler antenna cube (e.g., corresponding to the number of receive antenna elements 142 or the number of receiver modules 128). In this document, p is sometimes referred to as the “channel dimension” in the context of the range-Doppler antenna cube and the range bin matrix extracted therefrom. Each element of the range-Doppler antenna cube may encode the complex amplitude of the received signal for a particular range bin, Doppler bin, and RX channel. In one or more embodiments, a given RX channel patch of a range-Doppler antenna cube can be represented as a two-dimensional (2D) array of range-Doppler cells, where the complex amplitude of each cell corresponds to the average complex amplitude within the region boundaries in Cartesian space through a corresponding iso-Doppler line and an iso-distance line pair. That is, the boundaries of each range bin are defined by a corresponding pair of iso-distance lines, and the boundaries of each Doppler bin are defined by a corresponding pair of iso-Doppler lines. Each range-Doppler cell corresponds to a corresponding Doppler bin and a range bin pair.

[0066] Because the transmitter module 118 transmits chirps simultaneously in the DDM-MIMO radar system, information from all TX channels is represented in each element in the range-Doppler antenna cube. Each range bin represents the distance or spacing between the radar system and the target object. Each Doppler bin represents a Doppler shift value corresponding to the speed at which the target object may be traveling (e.g., relative to the self-speed of the radar system 100). Such speed can be calculated based on the determined Doppler shift associated with the target object.

[0067] At block 408, the signal processor 110 performs per-channel (e.g., per RX channel) AoA estimation using the range-Doppler antenna cube. In one or more embodiments, the signal processor 110 performs per-channel AoA estimation by extracting range bins from the range-Doppler antenna cube and performing a channel dimension FFT or DFT on each range-Doppler element of the extracted range bins to generate an FFT or DFT output matrix (i.e., where each FFT or DFT output matrix corresponds to a corresponding range bin of the range-Doppler antenna cube). Figures 5 to 8 An example of such per-channel AoA estimation is provided in more detail.

[0068] At block 410, the signal processor 110 performs DDM decoding of the range-Doppler antenna cube based on the FFT or DFT output matrix generated by the per-channel AoA estimation performed at block 408 to generate a decoded RDBM. Figures 5 to 8 Examples of how a signal processor according to various embodiments may generate a decoded RDBM are described in more detail.

[0069] At block 412, the signal processor 110 constructs a virtual MIMO array based on the decoded RDBM and the range-Doppler antenna cube.

[0070] At block 414 , the signal processor 110 generates target object position data based on the AoA estimate using the virtual MIMO array.

[0071] At block 416 , the signal processor 110 generates target object tracking data based on the target object position data.

[0072] Figure 5 An example diagram 500 is shown illustrating the generation of a decoded RDBM 510 based on a three-dimensional (3D) range-Doppler antenna cube 504 via a DDM decoding process. For example, a signal processor (e.g., Figure 1 The signal processor 110 of the radar system 100 may generate a range-Doppler antenna cube 504 (e.g., as a non-limiting example, corresponding to Figure 4 4 and 406 of method 400 of ). The range-Doppler antenna cube 504 can be a three-dimensional array of m x n x p arranged according to the axis 502 shown, where the first dimension (m) corresponds to Doppler bins (e.g., each defined by a corresponding iso-Doppler line), the second dimension (n) corresponds to the range bins (e.g., each defined by a corresponding iso-distance line), and the third dimension (p) corresponds to the RX channel. The signal processor can perform a DDM decoding process on the range-Doppler antenna cube 504 to generate a decoded RDBM 516. In one or more embodiments, the signal processor can separately process each range bin of the range-Doppler antenna cube (e.g., the range bin matrix 506) to generate a corresponding row (e.g., row 518) of the decoded RDBM 516, which can be an m x n matrix or a two-dimensional array according to the axis 514.

[0073] For example, as part of the DDM decoding process, the signal processor may perform a DFT or FFT on each range-Doppler bin of the range-Doppler antenna cube 504 in the channel dimension to obtain an output matrix 510. Each output matrix 510 may be represented as a matrix of range-Doppler bins corresponding to respective angles of arrival or angle bins, as indicated by axis 508. In one or more other embodiments, the DFT or FFT results may alternatively be represented as a matrix of angle-Doppler bins, each corresponding to a respective different range bin (see, e.g., Table 2). The signal processor may identify a peak position in the angle dimension of each Doppler bin of the output matrix 510. Because the transmitter data is encoded in the output matrix 510 according to a predetermined Doppler shift amount (e.g., determined by a DDM code) for each transmit channel, the signal processor may compare the peak position of each Doppler bin with peak positions in other Doppler bins corresponding to other transmit channels (e.g., TX2, TX3, TX4) based on the DDM code. This may be accomplished by the signal processor extracting Doppler bin groups 512 from the output matrix 510.

[0074] The signal processor may then compare the peak positions between each Doppler bin in the group 512 to determine how many of the peak positions of each group are aligned (e.g., how many of the peak positions of the group are in the same angle bin or within a predefined spacing of the same angle bin). The signal processor may determine whether the determined number of aligned peaks is greater than or equal to a predefined threshold. For each Doppler bin, if the number of aligned peaks in the corresponding group is greater than or equal to the predefined threshold, the signal processor may set the corresponding cell of the decoded RDBM to a binary value of 1, and if not, the signal processor may instead set the corresponding cell of the decoded RDBM 516 to a binary value of 0. Thus, each cell of the RDBM 516 having a value of 1 may be considered to correspond to a valid peak position, while cells having a value of 0 are not considered to correspond to a valid peak position.

[0075] When performing the DDM decoding process, the signal processor may extract individual range bins, such as range bin matrix 506 , from range-Doppler antenna cube 504 , and for each extracted range bin matrix, may generate a corresponding row, such as row 518 , of decoded RDBM 516 .

[0076] For example, Figure 6 A diagram illustrating a process 600 is shown by which a signal processor of a radar system (eg, as a non-limiting example, Figure 1 The signal processor 110 of the radar system 100) is based on the range-Doppler antenna cube 602 (e.g., Figure 5The signal processor generates a row of a decoded RDBM (referred to herein as a "decoded RDBM row 618") from the range bins extracted from the range-Doppler antenna cube 502 (an example embodiment of the range-Doppler antenna cube 504). First, the signal processor extracts the range bin matrix 604 from the range-Doppler antenna cube 604. The range-Doppler antenna cube 602 can be a three-dimensional array of dimensions mxnxp, where m represents the number of Doppler bins, n represents the number of range bins, and p represents the number of RX channels represented in the range-Doppler antenna cube. The range bin matrix 604 can be a two-dimensional matrix of dimensions mxp. For example, the columns of the range bin matrix 604 represent Doppler bins, and the rows of the range bin matrix represent RX channels. An example of the range bin matrix 604 is shown in Table 1 below.

[0077] D0 D1 ... D255 CH0 D0_CH0 D1_CH0 ... D255_CH0 CH1 D0_CH1 D1_CH1 ... D255_CH1 CH2 D0_CH2 D1_CH2 ... D255_CH2 CH3 D0_CH3 D1_CH3 ... D255_CH3 CH4 D0_CH4 D1_CH4 ... D255_CH4 CH5 D0_CH5 D1_CH5 ... D255_CH5 CH6 D0_CH6 D1_CH6 ... D255_CH6 CH7 D0_CH7 D1_CH7 ... D255_CH7 CH8 D0_CH8 D1_CH8 ... D255_CH8 CH9 D0_CH9 D1_CH9 ... D255_CH9 CH10 D0_CH10 D1_CH10 ... D255_CH10 CH11 D0_CH11 D1_CH11 ... D255_CH11 CH12 D0_CH12 D1_CH12 ... D255_CH12 CH13 D0_CH13 D1_CH13 ... D255_CH13 CH14 D0_CH14 D1_CH14 ... D255_CH14 CH15 D0_CH15 D1_CH15 ... D255_CH15

[0078] Table 1

[0079] In the example of Table 1, the range bin matrix 604 includes 256 columns, each column representing a corresponding Doppler bin. Each Doppler bin corresponds to a transmitted chirp. That is, if 256 chirps are transmitted via each TX channel of the radar system, the corresponding range bin matrix will include 256 Doppler bins. The range bin matrix 604 includes 16 rows, each representing a corresponding RX channel.

[0080] The signal processor then performs a channel dimension FFT on each range-Doppler cell of the range bin matrix 604 to generate an FFT output matrix 606. In one or more embodiments, the type of FFT that the signal processor performs on the range bin matrix 604 may depend on the number of RX channels represented in the range-Doppler antenna cube 602. For example, given a radar system with 16 RX channels represented in the range-Doppler antenna cube 602, the signal processor may perform a 16-point FFT on each range bin of the range-Doppler antenna cube 602 (including the range bin matrix 604). The FFT of the range bin matrix 604 generates an FFT output matrix 606 of dimension mxp. The columns of the FFT output matrix 606 represent Doppler bins; the rows of the FFT output matrix 606 represent angle bins, where each angle bin corresponds to a range of angles of arrival; and each cell of the FFT output matrix 606 represents an FFT result associated with a corresponding cell of the range bin matrix 604. In one or more other embodiments, the rows of the FFT output matrix 606 represent discrete angles of arrival, rather than angle bins. It should be appreciated that process 600 is not limited to the use of FFT, such that in one or more other embodiments, process 600 may instead use other suitable DFT techniques. An example of FFT output matrix 606 is shown in Table 2 below.

[0081] D0 D1 ... D255 θ0 D0_FFT0 D1_FFT0 ... D255_FFT0 θ1 D0_FFT1 D1_FFT1 ... D255_FFT1 θ2 D0_FFT2 D1_FFT2 ... D255_FFT2 θ3 D0_FFT3 D1_FFT3 ... D255_FFT3 θ4 D0_FFT4 D1_FFT4 ... D255_FFT4 θ5 D0_FFT5 D1_FFT5 ... D255_FFT5 θ6 D0_FFT6 D1_FFT6 ... D255_FFT6 θ7 D0_FFT7 D1_FFT7 ... D255_FFT7 θ8 D0_FFT8 D1_FFT8 ... D255_FFT8 θ9 D0_FFT9 D1_FFT9 ... D255_FFT9 θ10 D0_FFT10 D1_FFT10 ... D255_FFT10 θ11 D0_FFT11 D1_FFT11 ... D255_FFT11 θ12 D0_FFT12 D1_FFT12 ... D255_FFT12 θ13 D0_FFT13 D1_FFT13 ... D255_FFT13 θ14 D0_FFT14 D1_FFT14 ... D255_FFT14 θ15 D0_FFT15 D1_FFT15 ... D255_FFT15

[0082] Table 2

[0083] The signal processor then determines the maximum value of each Doppler bin (e.g., each column) of the FFT output matrix 606, and generates a Doppler bin maximum array 608 including the determined maximum values. For example, the Doppler bin maximum array 608 can be a one-dimensional array of length m, where each cell of the Doppler bin maximum array 608 represents a corresponding maximum value of a corresponding column (e.g., Doppler bin) of the FFT output matrix 606. An example of the Doppler bin maximum array 608 is shown in Table 3 below.

[0084] D0 D1 ... D255 MAX D0_MAX D1_MAX ... D255_MAX

[0085] Table 3

[0086] The signal processor then applies each column threshold to the FFT output matrix 606 to generate a MAX map 610. It should be understood that any "map" mentioned herein can be represented as a matrix or a two-dimensional array. Here, a "MAX" map refers to the maximum value of the maximum value, which can be a sparse map, in which the cell corresponding to the position of the maximum value of each column has a predetermined non-zero value VAL, and all other cells of the MAX map have a value of 0. The signal processor 110 can combine the decoded RDBM rows to generate a decoded RDBM. In one or more embodiments, the signal processor sets any cell with a value greater than or equal to the threshold of the corresponding column in the FFT output matrix 606 to a predetermined non-zero value VAL, and sets all other cells (i.e., those cells whose values ​​are less than their corresponding thresholds) to zero. For example, in order to generate a MAX map 610, the threshold of a given column (e.g., a Doppler bin) is set to the corresponding value of the Doppler bin maximum value array 608. An example of a MAX map 610 is shown in Table 4 below:

[0087]

[0088]

[0089] Table 4

[0090] In the example of Table 4, cells in the FFT output matrix 606 whose values ​​are equal to or greater than the corresponding maximum value of the Doppler bin maximum value array 608 are replaced with a predetermined value VAL, and all other cells are replaced with zeros. For example, the values ​​of cells D0_FFT10, D1_FFT4, and D255_FFT14 are equal to or greater than the corresponding maximum value of the Doppler bin maximum value array 608, and are therefore replaced with VAL. In this way, the non-zero cells in the MAX map 610 indicate the angle bin or arrival angle corresponding to the detected peak value (e.g., peak signal amplitude) of each Doppler bin.

[0091] The signal processor then generates an aligned MAX map 612 based on the MAX map 610, wherein the aligned MAX map 612 includes groups of columns of the MAX map 610. The columns of each group correspond to respective unambiguous velocities, thereby accounting for the Doppler domain shifts of the TX channels represented in the group. Each group includes a respective column for each TX channel, such that the number of columns in a given group of the aligned MAX map 612 corresponds to the number of TX channels.

[0092] For example, in a DDM-MIMO radar system, the range-Doppler antenna cube 602 (and thus the range bin matrix 604, the FFT output matrix 606, and the MAX map 610) includes corresponding TX channel data sets for all TX channels of the radar system, wherein each TX channel data set is offset (with respect to the Doppler bin dimension) from and overlaps with the TX channel data sets of the other TX channels. Here, a set of "TX channel data" for a given TX channel (e.g., TX1, TX2, TX3, or TX4) refers to data (e.g., ADC samples or data derived from such samples) representing a return signal corresponding to a reflection of a chirp transmitted via the TX channel. For example, in the MAX map 610, the TX1 channel data may have an offset of 0 Doppler bins, the TX2 channel data may have an offset of 50 Doppler bins, the TX3 channel data may have an offset of 120 Doppler bins, and the TX4 channel data may have an offset of 204 Doppler bins, but it should be understood that other combinations of Doppler bin offsets may be used instead. Thus, for Doppler bin 0 of the MAX map 610 and given the Doppler bin offsets described above, the TX1 channel data associated with Doppler bin D0 is the D0 column of the MAX map 610, the TX2 channel data associated with Doppler bin D0 is the D49 column of the MAX map 610, the TX3 channel data associated with Doppler bin D0 is the D119 column of the MAX map 610, and the TX3 channel data associated with Doppler bin D0 is the D229 column of the MAX map 610. Thus, the aligned MAX map 612 is of dimension (m*N ch )xp two-dimensional matrix, where N ch is the number of TX channels of the radar system. Thus, given a radar system with 4 TX channels, m=256 Doppler bins, and p=16 RX channels, the aligned MAX map 612 has 1024 columns and 16 rows. An example of the aligned MAX map 612 is shown in Table 5 below.

[0093] D0_TX1 D0_TX2 D0_TX3 D0_TX4 D1_TX1 D1_TX2 D1_TX3 D1_TX4 ... D255_TX4 θ0 0 0 0 0 0 0 0 0 ... 0 θ1 0 0 0 0 0 0 0 0 ... 0 θ2 0 0 0 0 0 0 0 0 ... 0 θ3 0 0 0 0 0 VAL 0 0 ... 0 θ4 0 0 0 0 VAL 0 VAL 0 ... VAL θ5 0 0 0 0 0 0 0 0 ... 0 θ6 0 0 0 0 0 0 0 0 ... 0 θ7 0 0 0 0 0 0 0 0 ... 0 θ8 0 0 0 0 0 0 0 0 ... 0 θ9 0 0 0 0 0 0 0 0 ... 0 θ10 VAL VAL VAL VAL 0 0 0 0 ... 0 θ11 0 0 0 0 0 0 0 0 ... 0 θ12 0 0 0 0 0 0 0 0 ... 0 θ13 0 0 0 0 0 0 0 VAL ... 0 θ14 0 0 0 0 0 0 0 0 ... 0 θ15 0 0 0 0 0 0 0 0 ... 0

[0094] Table 5

[0095] In the example of Table 5, aligned MAX map 612 includes multiple groups of columns extracted from MAX map 610. Each group includes one column for each of transmit channels TX1, TX2, TX3, and TX4. The signal processor extracts the columns in a given group from MAX map 610 based on the Doppler bin associated with the group and the Doppler shift (sometimes referred to as "spacing") associated with the TX channel represented by each column in the given group.

[0096] For example, the first group includes columns D0_TX1, D0_TX2, D0_TX3, D0_TX4, and the second group includes columns D1_TX1, D1_TX2, D1_TX3, D1_TX4. For the first group of columns D0_TX1, D0_TX2, D0_TX3, and D0_TX4, a given interval relative to channel TX1 is 0 Doppler bins for channel TX1, 50 Doppler bins for channel TX2, 120 Doppler bins for channel TX3, and 230 Doppler bins for channel TX4. D0_TX1 corresponds to column D0 of the MAX map 610, D0_TX2 corresponds to column D50 of the MAX map 610, D0_TX2 corresponds to column D120 of the MAX map 610, and D0_TX3 corresponds to column D230 of the MAX map 610. The spacing associated with each TX channel does not vary between groups, such that for the second group, D1_TX1 corresponds to column D1 of the MAX map 610, D1_TX2 corresponds to column D51 of the MAX map 610, D1_TX2 corresponds to column D121 of the MAX map 610, and D1_TX3 corresponds to column D230 of the MAX map 610. When determining the column of the MAX map 610 that corresponds to a given column of the aligned MAX map 612, indices exceeding 255 wrap around. For example, the 230th group of aligned MAX maps 612 includes D230_TX1, D230_TX2, D230_TX3, and D230_TX4. D230_TX1 corresponds to column D230 of the MAX map 610. D230_TX2 corresponds to column D24 of the MAX map 610 (i.e., since (230+50)%256=24). D230_TX3 corresponds to column D94 of the MAX map 610 (ie, since (230+120)%256=94). D230_TX4 corresponds to column D204 of the MAX map 610 (ie, since (230+230)%256=204).

[0097] As shown in the example of Table 5, the values ​​VAL of the first group are all aligned in the same row corresponding to the angle bin θ10, while only two of the values ​​VAL of the second group are placed in the same angle bin. This indicates that the maximum value of the first group is more likely to respond to a valid peak than the maximum value of the second group, as evaluated by the signal processor in a subsequent thresholding step.

[0098] The signal processor generates a combined MAX map 614 based on the aligned MAX maps 612 by taking a scalar product of the rows in each group of aligned MAX maps 612, effectively combining each group into a single corresponding column of the combined MAX map 614. For example, the length of the scalar product can be the same as the number of TX channels, given as N ch , and the coefficients used are each (1 / N ch ). Given a system with 4 TX channels, the length of the scalar product will be 4, and the coefficients will each be 1 / 4. For each row in each set of aligned MAX maps 612, the result of the scalar product operation for that row is equal to the sum of the elements of that row divided by 4. An example of a combined MAX map 614 is shown in Table 6 below.

[0099] D0 D1 ... D255 θ0 0 0 ... 0 θ1 0 0 ... 0 θ2 0 0 ... 0 θ3 0 VAL / 4 ... 0 θ4 0 VAL / 2 ... VAL / 4 θ5 0 0 ... VAL / 2 θ6 0 0 ... 0 θ7 0 0 ... 0 θ8 0 0 ... 0 θ9 0 0 ... 0 θ10 VAL 0 ... 0 θ11 0 0 ... 0 θ12 0 0 ... 0 θ13 0 VAL / 4 ... 0 θ14 0 0 ... VAL / 4 θ15 0 0 ... 0

[0100] Table 6

[0101] As shown in the example of Table 6, the values ​​of the cells at D0 and CH10 are equal to VAL because all of the maximum values ​​in the first group (corresponding to D0) in Table 5 are aligned in angle bin θ10. In contrast, columns D0 and D255 include fractional values ​​VAL / 2 and VAL / 4 across multiple angle bins because the aligned MAX maps 612 for the corresponding groups in Table 5 include the maximum values ​​in those angle bins.

[0102] In one or more embodiments, only those values ​​VAL in the aligned maximum map of a given group that are in the same angle bin are considered to be "aligned" in the angle bin (i.e., they are considered to have the same or similar angle of arrival). In one or more other embodiments, the signal processor may apply peak relaxation by adjusting a tolerance that defines whether two values ​​VAL in a given row (i.e., angle bin) of a group are considered to be "aligned." For example, if two values ​​VAL in a group are in adjacent angle bins or within a predefined angle bin range relative to each other, the peak relaxation condition adopted by the signal processor may define the two values ​​as aligned. For example, when such a peak relaxation condition is adopted, the signal processor may define each value VAL in the rows D1_TX1, D1_TX2, D1_TX3 of the aligned MAX map represented in Table 5 as aligned because they are in adjacent angle bins (e.g., angle bins θ3 and θ4).

[0103] After generating the aligned MAX map, the signal processor 110 applies a threshold to the combined MAX map 614 to identify cells corresponding to valid peaks. For example, if the value of a cell of the combined MAX map 614 exceeds the decoding threshold K, the cell may correspond to a valid peak. The signal processor may compare the value of each cell of the combined MAX map 614 with the threshold (K*VAL) / N. ch The comparison is performed, and the cell values ​​greater than or equal to the threshold return a value of 1 in the filtered maximum value map 616, while other cell values ​​less than the threshold return a value of 0. ch =4, a decoding threshold K=4 may be used, which in this example requires that the maximum values ​​in all 4 TX channels are aligned in the same angle bin so that only the cell values ​​of the combined MAX map 614 with the value of VAL are considered valid. In one or more other embodiments, a decoding threshold K=3 may be used, which in this example requires that the maximum values ​​in 75% of the TX channels are aligned in the same angle bin so that the cell values ​​of the combined MAX map 614 with the value of 3VAL / 4 are considered valid. An example of the filtered MAX map 616 is shown in Table 7 below.

[0104]

[0105]

[0106] Table 7

[0107] In the example of Table 7, a decoding threshold K=4 is used, and the cell at column D0 and row CH10 has a value of 1, while all other cells in column D0 have a value of 0. The cells of column D1 are all 0 because the signal processor determined that Doppler bin D1 does not contain a valid peak.

[0108] The signal processor then generates a decoded RDBM row 618 based on the filtered MAX map 616 by determining the maximum value for each column (ie, each Doppler bin) of the filtered maximum map 616. An example of a decoded RDBM row 618 is shown in Table 8 below.

[0109] D0 D1 ... D255 MAX 1 0 ... 0

[0110] Table 8

[0111] The signal processor may repeat process 600 for each range bin of range-Doppler antenna cube 602, and the resulting decoded RDBM rows 618 may be combined to form a decoded RDBM (eg, Fig.10 The decoded RDBM 1000).

[0112] Figure 7An illustrative process flow for a method 700 is shown by which a decoded RDBM representing a transmitted signal reflected by a target object in an environment surrounding a DDM-MIMO radar system (e.g., according to a DDM scheme, such as Figure 2 The characteristics of the sampled return signal corresponding to the reflection of the chirp (transmitted by the DDM scheme shown in the timing diagram 200 of the radar MCU). According to one or more embodiments, the method 700 can be performed using either or both of the radar controller and the signal processor of the radar MCU. Figure 1 The method 700 is described with reference to elements of the radar system 100 , but it should be understood that this is illustrative and not limiting, at least because other suitable radar systems may be used to perform the method 700 in one or more other embodiments.

[0113] At block 702, the signal processor 110 of the radar system 100 generates a range-Doppler antenna cube. For example, the signal processor 110 of the radar system 100 may generate a range-Doppler antenna cube by performing a fast time FFT and a slow time FFT on raw ADC data (e.g., digital signals) representing the range of the antenna cube generated by the transmitter module 118 of the radar system 100 according to a DDM scheme, such as Figure 2 The return signal corresponds to the reflected chirp transmitted by the DDM scheme shown in the timing diagram 200. In one or more other embodiments, the signal processor 110 may use other suitable DFT techniques instead of fast-time and slow-time FFTs for range and Doppler compression.

[0114] As a non-limiting example, blocks 704 and 706 may correspond to Figure 4 408 of method 400. At block 704, the signal processor 110 generates a range bin matrix from the range-Doppler antenna cube.

[0115] At block 706, the signal processor 110 performs a channel dimension FFT on each range-Doppler cell of the extracted range bin matrix to generate an FFT output matrix. In one or more embodiments, the channel dimension FFT may be an N-point FFT (e.g., based on the number N of RX channels represented in the range-Doppler antenna cube). The output matrix may include columns representing corresponding Doppler bins and rows representing corresponding angles of arrival or angle bins.

[0116] As a non-limiting example, blocks 708-718 may correspond to Figure 4At block 708, the signal processor 110 determines the peak location in the output matrix. For example, the signal processor may determine the peak location by determining the angle bin (ie, Doppler bin) containing the highest amplitude in each column of the output matrix.

[0117] At block 710, for each Doppler bin of the output matrix, the signal processor 110 compares the peak position of the Doppler bin with the peak positions of the Doppler bins corresponding to other TX channels. For example, and for a given Doppler bin (here assumed to represent the first TX channel TX1), the signal processor 110 can identify other Doppler bins in the output matrix representing other TX channels based on the offset (in the Doppler domain) applied to each TX channel data set according to the corresponding DDM code. Each TX channel data set for each TX channel can be offset by a different predetermined amount. Returning to the example where the offset is 0 bins for TX1, 50 bins for TX2, 120 bins for TX3, and 230 bins for TX4, and when performing this comparison for Doppler bin D0, the signal processor 110 compares the peak positions of Doppler bins D0, D49, D119, and D229. The signal processor 110 can determine the number of aligned peak positions associated with each Doppler bin (across all TX channels) by performing this comparison. In one or more embodiments, the signal processor 110 may be configured to determine that two peaks are "aligned" if they are in the same angle bin. In one or more other embodiments, the signal processor 110 may be configured to determine that two peaks are "aligned" if they are within a certain range of angle bins of each other (e.g., within a spacing of 1 angle bin, 2 angle bins, 3 angle bins, etc.).

[0118] At block 712, the signal processor 110 determines whether the number of aligned peak positions (sometimes referred to herein as "position matching peaks") is greater than or equal to a threshold in order to determine which peaks are "valid". In one or more embodiments, the threshold may be equal to the number of TX channels of the radar system 100 (e.g., effectively requiring peaks to be aligned across all TX channels in order to be considered valid peaks), which may reduce the probability of false alarms. In one or more other embodiments, the threshold may be less than the number of TX channels of the radar system 100, which may reduce the probability of missed peak detections. For example, the threshold used by the signal processor to identify valid peaks may be selected based on a desired balance between the probability of false alarms and the probability of missed peaks, which may be application dependent.

[0119] At block 714, the signal processor 110 generates a decoded RDBM row based on the results of applying the threshold at block 712. For example and for each cell of the decoded RDBM row, if it is determined that the cell corresponds to a Doppler cell of the corresponding output matrix having a number of position matching peaks greater than or equal to the threshold, the signal processor 110 may set the value of the cell to a binary 1. For each cell of the decoded RDBM row, the signal processor 110 may set the value of the cell to a binary 0 in response to determining that the cell corresponds to a Doppler cell of the corresponding output matrix having a number of position matching peaks less than the threshold.

[0120] At block 716, in response to determining that all range bin matrices of the range-Doppler antenna cube have been processed, the method 800 proceeds to block 718. Otherwise, in response to determining that unprocessed range bin matrices remain, the method 700 returns to block 704 and the signal processor 110 extracts the next unprocessed range bin matrix of the range-Doppler antenna cube.

[0121] At block 718, the signal processor 110 outputs the decoded RDBM. For example, the signal processor 110 may generate the decoded RDBM by combining the decoded RDBM rows generated at block 714 for each range bin matrix of the range-Doppler antenna cube.

[0122] Figure 8 An illustrative process flow for a method 800 is shown by which a decoded RDBM representing a transmitted signal reflected by a target object in an environment surrounding a DDM-MIMO radar system (e.g., according to a DDM scheme, such as Figure 2 The method 800 may correspond to the characteristics of the sampled return signal corresponding to the reflection of the chirp transmitted by the DDM scheme shown in the timing diagram 200 of FIG. Figure 7 According to one or more embodiments, the method 800 may be performed using either or both of a radar controller and a signal processor of a radar MCU. Figure 1 Elements of the radar system 100 and Figure 6 The method 800 is described with reference to process 600 of FIG. 8 , but it should be understood that this is illustrative and not limiting, at least because other suitable radar systems may be used to perform the method 800 in one or more other embodiments.

[0123] At block 802, the signal processor 110 of the radar system 100 generates the range-Doppler antenna cube 602. For example, the signal processor 110 of the radar system 100 may generate the range-Doppler antenna cube 602 by performing a fast time FFT and a slow time FFT on raw ADC data (e.g., digital signals) representing the range-Doppler antenna cube 602 generated by the transmitter module 118 of the radar system 100 according to a DDM scheme, e.g. Figure 2 The DDM scheme shown in the timing diagram 200 transmits a return signal corresponding to the reflected chirp.

[0124] As a non-limiting example, blocks 804 and 806 may correspond to Figure 4 At block 804 , the signal processor 110 generates a range bin matrix, such as the range bin matrix 604 , from the range-Doppler antenna cube 602 .

[0125] At block 806, the signal processor 110 performs a channel dimension FFT on each range-Doppler cell of the extracted range bin matrix to generate an FFT output matrix, such as the FFT output matrix 606. In one or more embodiments, the channel dimension FFT may be a 16-point FFT (e.g., based on the number of RX channels represented in the range-Doppler antenna cube 602).

[0126] As a non-limiting example, blocks 808-822 may correspond to Figure 4 At block 808, the signal processor 110 generates a Doppler bin maximum array, such as the Doppler bin maximum array 608, which represents the maximum values ​​detected in each column in the FFT output matrix.

[0127] In one or more embodiments, the Doppler bin maximum array generated at block 810 may be used to generate a row of coherently integrated range-Doppler maps (RDMs), such that the Doppler bin maximum arrays generated for each range bin of the range-Doppler antenna cube 602 may be combined to generate such a coherently integrated RDM. In this context, an RDM may be distinguished from an RDBM because an RDBM includes a matrix or 2D array of binary values ​​(e.g., 0 and 1), whereas an RDM may include a matrix or 2D array of signal amplitudes. Fig. 9An example of such a coherently integrated RDM 900 is shown. In the coherently integrated RDM 900, data from each TX channel is encoded according to its corresponding DDM code, so that each TX channel data set is represented in the RDM 900 and offset by a predetermined number of Doppler bins, where the offset is different for each TX channel (e.g., as defined by the corresponding DDM code). For example, data corresponding to the first TX channel TX1 representing a speed of approximately -30 m / s is placed in Doppler bin 902. Data corresponding to the second TX channel TX2 representing a speed of approximately -30 m / s is placed in Doppler bin 904 and offset by 50 bins from Doppler bin 902. Data corresponding to the third TX channel TX3 representing a speed of approximately -30 m / s is placed in Doppler bin 906 and offset by 120 bins from Doppler bin 902. Data corresponding to the fourth TX channel TX4 , representing a velocity of approximately −30 m / s, is placed in Doppler bin 908 , and is offset from Doppler bin 902 by 230 bins.

[0128] Back to Figure 8 At block 810 of method 800, the signal processor 110 generates a MAX map, such as the MAX map 610, based on the Doppler bin maximum value array and the FFT output matrix. For example, the signal processor 110 may generate the MAX map by replacing the cell values ​​of the FFT output matrix corresponding to each column maximum value identified in the Doppler bin maximum value array with a predetermined value VAL and replacing all other cell values ​​with zeros.

[0129] At block 812, the signal processor 110 generates an aligned MAX map, such as the aligned MAX map 612, based on the MAX map generated at block 810. For example, the signal processor 110 may generate the aligned MAX map by populating the column groups of the aligned MAX map with the columns of the MAX map generated at block 810 corresponding to the same Doppler bins across each TX channel while taking into account a predetermined offset associated with each TX channel, wherein such offset is known and results from a DDM scheme used when transmitting chirps using the TX module 118.

[0130] At block 814, the signal processor 110 generates a combined MAX map, such as the combined MAX map 614, based on the average values ​​of each row in each set of aligned MAX maps. For example, the signal processor 110 may generate a combined MAX map based on the average values ​​of each row in each set of aligned MAX maps by taking the coefficient (1 / N ch ) each row of each aligned MAX map has a length N ch The combined MAX map is generated by taking the scalar product of

[0131] At block 816, the signal processor 110 generates a filtered MAX map, such as the filtered MAX map 616, by applying a threshold to the elements of the combined MAX map. For example, the threshold may be (K*VAL) / N ch , where VAL is the predetermined value used at block 810, K is the decoder threshold coefficient, and N ch is the number of TX channels represented in the range-Doppler antenna cube 602. Bin values ​​greater than or equal to the threshold result in an output of 1 for each of those bins in the filtered MAX map, while bin values ​​less than the threshold result in an output of 0 for those bins in the filtered MAX map.

[0132] At block 818, the signal processor 110 generates a decoded RDBM row based on the filtered MAX map, such as the decoded RDBM row 618. For example, the signal processor 110 may generate the decoded RDBM row by calculating the maximum value of each column of the filtered MAX map.

[0133] At block 820, if all range bin matrices of the range-Doppler antenna cube 602 have been processed, the method 800 proceeds to block 822. Otherwise, if unprocessed range bin matrices remain, the method 800 returns to block 804 and the signal processor 110 extracts the next unprocessed range bin matrix of the range-Doppler antenna cube 602.

[0134] At block 822, the signal processor 110 outputs a decoded RDBM. For example, the signal processor 110 may generate a decoded RDBM by combining the decoded RDBM rows generated at block 818 for each range bin of the range-Doppler antenna cube.

[0135] For example, Fig.10 The decoded RDBM 1000 is shown, which can be obtained by Figure 1 The MCU 104 outputs at block 822. The decoded RDBM 1000 corresponds to Fig. 9 The decoded version of the coherently integrated RDM 900. The data points of the decoded RDBM 1000 correspond to peaks that are considered "valid" with respect to defined validity conditions applied by the signal processor 110 (e.g., based on the value of K and / or the amount of peak relaxation applied).

[0136] Compared to conventional decoding techniques, the above-described embodiments of the DDM decoding technique can advantageously reduce the false alarm probability without the need to apply the CFAR algorithm or other decoding algorithms that depend on such peak and threshold detection steps, which further advantageously increases the decoding speed compared to such conventional decoding techniques. For the embodiments of the DDM decoding technique described above, there is a false alarm probability PFA The analytical closed-form solution of .

[0137] For example, P in one or more embodiments of the present invention FA Depends on the decoding threshold K, the number of TX channels N ch and the number of angle bins N used for coherent integration a , the number of angle bins may be equal to the number of RX channels or RX antennas.

[0138] P FA It can be calculated by formulating the problem as a Bernoulli trial. The probability that the noise exceeds the index-based detection threshold is equal to N ch At least K times the total number N a The maximum value of the coherently integrated data set found in the same bin of .

[0139] The probability of a noise-only acquisition for producing K matches is:

[0140]

[0141] The probability of a noise-only acquisition to produce K+1 matches is:

[0142]

[0143] Etc. The false alarm probability is the sum of all possible cases where the noise sample provides a greater (or equal) number of matches than the applied threshold K:

[0144]

[0145] Assume 2K>N ch , then the above equation is valid, otherwise the equation needs to be adjusted using the inclusion-exclusion principle. However, the above assumption is applicable to the interval The value k chosen in .

[0146] Unlike the traditional CFAR algorithm, no assumption is made about the distribution in the range-Doppler dimension, and only each bin in the channel dimension is assumed to be independent, and it can be viewed as the result The probability of a positive outcome and The Bernoulli variable for the probability of a negative outcome.

[0147] Set P by modifying K FA , because N a and N ch For a given system, it is fixed. For lower P FA , the value of K increases. However, this comes at the expense of reduced sensitivity to overlapping targets and can reduce the detectability of valuable targets. Therefore, based on the unambiguity speed and use case, the value of K is increased in PFA With the detection probability P D There is a tradeoff.

[0148] For N ch Low values ​​of (e.g., 4 TX channels) improve P FA and P D One approach to both is to use a larger allowed value of K, which will ensure correct decoding and include CFAR detection to ensure a sufficiently low probability of false alarms.

[0149] For N ch For high values ​​of K, no CFAR detection is needed, assuming that excessive overlap is avoided by increasing the number of Doppler bins. For example, 1024 Doppler bins can be used for a system with 12 TX channels, with a threshold of K=8, and no CFAR detection is needed.

[0150] The above description refers to elements or nodes or features being "connected" or "coupled" together. As used herein, unless otherwise explicitly stated, "connected" means that one element is directly joined to another element (or directly communicates with another element), and not necessarily mechanically joined. Similarly, unless otherwise explicitly stated, "coupled" means that one element is directly or indirectly joined to another element (or directly or indirectly communicates with another element), and not necessarily mechanically joined. Therefore, although the schematic diagrams shown in the figures depict an exemplary arrangement of elements, additional intervening elements, devices, features, or components may be present in one or more embodiments of the depicted subject matter.

[0151] Although the operation of the method herein is shown and described in a particular order, the order of operation of each method can be changed so that some operations can be performed in reverse order, or so that some operations can be performed at least partially simultaneously with other operations. In another embodiment, instructions or sub-operations of different operations can be implemented in a discontinuous and / or alternating manner.

[0152] It should also be noted that at least some of the operations of the methods described herein can be implemented using software instructions stored on a computer-usable storage medium for computer execution. As an example, an embodiment of a computer program product includes a computer-usable storage medium for storing a computer-readable program. The computer-usable or computer-readable storage medium can be an electronic, magnetic, optical, electromagnetic, infrared or semiconductor system (or device or apparatus). Examples of non-temporary computer-usable storage media and computer-readable storage media include semiconductor or solid-state memory, magnetic tape, removable computer disk, random access memory (RAM), read-only memory (ROM), rigid disk and optical disk. Current examples of optical disks include high-density disks with read-only memory (CD-ROM), high-density disks with read / write (CD-R / W) and digital video disks (DVD).

[0153] Alternatively, the embodiments described herein may be implemented entirely in hardware or in an implementation scheme containing both hardware elements and software elements. In an embodiment using software, the software may include but is not limited to firmware, resident software, microcode, etc.

[0154] Although at least one exemplary embodiment has been presented in the above detailed description, it should be understood that there are a large number of variations. It should also be understood that one or more exemplary embodiments described herein are not intended to limit the scope, applicability or configuration of the claimed subject matter in any way. In fact, the above detailed description will provide a convenient guide for implementing the one or more embodiments described to those skilled in the art. It should be understood that various changes can be made to the function and arrangement of the elements without departing from the scope defined by the claims, and the scope defined by the claims includes known equivalents and foreseeable equivalents at the time of filing this patent application.

Claims

1. A radar system, characterized in that: include: a plurality of transmitter modules configured to transmit a plurality of transmission signals according to a Doppler domain multiplexing (DDM) scheme; a plurality of receiver modules configured to receive reflections of the plurality of transmit signals reflected by at least one object and to generate digital signals based on the received reflections; A signal processor, the signal processor being configured to: generating a range-Doppler antenna cube representing the digital signal, the range-Doppler antenna cube comprising at least a plurality of range bins and a plurality of Doppler bins; For each range bin of the plurality of range bins of the range-Doppler antenna cube: extracting a range bin matrix from the range-Doppler antenna cube; performing a discrete Fourier transform (DFT) on each range-Doppler element of the range bin matrix in a channel dimension to produce an output matrix; determining peak positions in the output matrix; for each Doppler bin, comparing associated peak locations across all transmit channels represented in the output matrix to identify a location matching peak associated with the Doppler bin; as well as generating a decoded RDBM row based on the position matching peak; and A decoded RDBM is generated based on the decoded RDBM rows.

2. The radar system according to claim 1, characterized in that The signal processor for generating the decoded RDBM row is additionally configured to: For each of the Doppler bins of the output matrix, a binary value is generated indicating whether the number of position matching peaks associated with the Doppler bin exceeds a predetermined threshold.

3. The radar system according to claim 2, characterized in that The signal processor for determining the peak positions of the output matrix is ​​additionally configured to: For each specific Doppler bin of the output matrix: Determine the maximum value; comparing the cell value of the particular Doppler bin to the determined maximum value; in response to a first cell of the particular Doppler bin having a value greater than or equal to the determined maximum value, updating the cell value of the first cell to be equal to a predetermined value; as well as in response to a second cell of the particular Doppler bin having a value less than the determined maximum value, updating the cell value of the second cell to be equal to zero; as well as A first matrix is ​​generated based on the updated cell values ​​for each particular Doppler bin of the output matrix.

4. The radar system according to claim 3, characterized in that The signal processor for comparing the associated peak positions is additionally configured to generate a second matrix comprising groups of Doppler bins, wherein each group of Doppler bins comprises a column of the first matrix representing each of the transmit channels.

5. The radar system according to claim 4, characterized in that Each set of the columns of the second matrix adjusted for a transmit channel offset in a Doppler dimension corresponds to a same unambiguous velocity, wherein the transmit channel offset is defined according to an associated DDM code.

6. The radar system according to claim 5, characterized in that The signal processor for generating the decoded RDBM rows is further configured to generate a third matrix by computing a scalar product of the cells in each row of each group of the second matrix, wherein the result of the scalar product for a given group of the second matrix forms a corresponding column of the third matrix.

7. A method, characterized in that include: generating, by a signal processor of the radar system, a range-Doppler antenna cube representing a digital signal corresponding to a signal reflected by an object, the range-Doppler antenna cube comprising at least a plurality of range bins and a plurality of Doppler bins; and A decoded range-Doppler bitmap (RDBM) is generated by the signal processor by: for each range bin of the plurality of range bins of the range-Doppler antenna cube: extracting a range bin matrix from the range-Doppler antenna cube; performing a discrete Fourier transform on each range-Doppler cell of the range-Doppler antenna cube to produce an output matrix; determining a peak position in each Doppler bin of the output matrix; for each of the Doppler bins of the output matrix, comparing associated peak locations across all transmit channels represented in the output matrix to identify a location matching peak associated with the Doppler bin; generating a decoded RDBM row based on the position matching peak in each Doppler bin; as well as The decoded RDBM rows are combined to produce the decoded RDBM.

8. The method according to claim 7, characterized in that Producing the decoded RDBM row additionally includes: For each of the Doppler bins of the output matrix, a binary value is generated indicating whether the number of position matching peaks associated with the Doppler bin exceeds a predetermined threshold.

9. The method according to claim 8, characterized in that Determining the peak position in each Doppler bin of the output matrix comprises: For each specific Doppler bin of the output matrix: determining a maximum value for the particular Doppler bin; comparing the cell value of the particular Doppler bin to the determined maximum value; in response to a first cell of the particular Doppler bin having a value greater than or equal to the determined maximum value, updating the cell value of the first cell to be equal to a predetermined value; and in response to a second cell of the particular Doppler bin having a value less than the determined maximum value, updating the cell value of the second cell to be equal to a predetermined value; and A first matrix is ​​generated based on the updated cell values ​​for each particular Doppler bin of the output matrix.

10. The method according to claim 9, characterized in that Comparing the associated peak positions further comprises: A second matrix is ​​generated comprising groups of columns of the first matrix, wherein the columns of each group adjusted for a transmit channel offset in a Doppler dimension correspond to the same unambiguous velocity, wherein the transmit channel offset is defined according to an associated DDM code.

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