Frequency division multiplexing with polyphase shifters

Abstract

This document describes a technique and system for frequency division multiplexing (FDM) using a polyphase shifter. A radar system may include a transmitter, a receiver, a polyphase shifter, and a processor. The transmitter transmits electromagnetic (EM) signals in an FDM scheme, and the receiver detects the EM signals reflected by an object. The received EM signals comprise multiple channels. The processor controls the polyphase shifter to introduce a phase shift into the EM signals. The processor can also divide the Doppler spectrum of the received EM signals into multiple sectors representing corresponding frequency ranges. Each channel is associated with a corresponding sector. The processor can use incoherent integration across sectors to determine potential detections of objects, including aliasing detections and actual detections. The processor can then determine the actual detection. In this way, the described FDM technique using a polyphase shifter can resolve Doppler ambiguity in the received EM signals.

Description

Background Technology

[0001] Radar systems transmit and receive electromagnetic (EM) signals for object detection and tracking. In automotive applications, radar systems provide information about the vehicle's environment and can play a significant role in advanced driver assistance systems (ADAS). Highly automated systems typically require high-resolution radar data in terms of range, Doppler, and angular dimensions. A popular approach to achieving improved angular dimension is multiple-input multiple-output (MIMO) radar technology, which provides a relatively large virtual array with reduced angular ambiguity. However, MIMO technology can provide insufficient Doppler discrimination. Summary of the Invention

[0002] This document describes techniques and systems for frequency division multiplexing (FDM) using polyphase shifters. In some examples, radar systems mounted on vehicles include multiple transmitters, multiple receivers, multiple polyphase shifters, and a processor. The transmitters can transmit electromagnetic (EM) signals in an FDM scheme. The receivers can receive EM signals, comprising multiple channels, reflected by one or more objects. The polyphase shifters can introduce at least three potential phase shifts into the transmitted, received, or both of the EM signals. The polyphase shifters are operatively connected to the transmitters, receivers, or a combination of both. The processor can control the polyphase shifters to introduce phase shifts. The processor can also divide the Doppler spectrum of the received EM signals into multiple sectors representing corresponding frequency ranges. Each channel is associated with a corresponding sector. The processor can use the incoherent integration of the received EM signals across sectors to determine potential detection of an object. The processor can then determine the actual detection. In this way, the described FDM technique utilizing polyphase shifters can resolve Doppler ambiguity in the received EM signals.

[0003] This document also describes the methods performed by the systems summarized above and other configurations of the radar systems described herein, as well as the apparatus for performing these methods.

[0004] This invention provides a simplified concept related to enabling FDM technology using multiphase shifters in radar systems, which is further described in the detailed embodiments and accompanying drawings. This invention is not intended to identify essential features of the claimed subject matter, nor is it intended to define the scope of the claimed subject matter. Attached Figure Description

[0005] This document describes in detail one or more aspects of slow time-frequency division multiplexing using multiphase shifters, with reference to the following figures. Throughout the figures, the same numbers are generally used to refer to similar features and components:

[0006] Figure 1 An example environment in which a radar system according to the technology of this disclosure can use FDM utilizing a multiphase shifter is shown;

[0007] Figure 2 An example configuration of a radar system using FDM with a multiphase shifter in a vehicle, according to the technology of this disclosure, is shown;

[0008] Figure 3 , Figure 4-1 , Figure 4-2 , Figure 5-1 and Figure 5-2 An example conceptual diagram of a radar system using FDM with multiphase shifters is shown;

[0009] Figure 6 An example diagram of the transmitted EM signal using an FDM employing a multiphase shifter is shown;

[0010] Figure 7 An example diagram of the received EM signal, represented by a Doppler bin, is shown using a radar system employing an FDM with a multiphase shifter;

[0011] Figure 8 An example method for determining the Doppler frequency of an object using an FDM system that utilizes a multiphase shifter is shown.

[0012] Figures 9-11 An example graphical representation of the association between channels and sectors in a radar system using FDM with multiphase shifters is shown; and

[0013] Figures 12-17 An example flowchart is shown for a radar system that uses FDM with multiphase shifters to perform incoherent integration and determine the actual detection associated with an object. Detailed Implementation

[0014] Overview

[0015] Radar systems can be configured as an important sensing technology used by vehicle-based systems to acquire information about their surroundings. For example, vehicle-based systems can use radar systems to detect objects in or near the road and take necessary actions (e.g., reduce speed, change lanes) to avoid collisions.

[0016] Radar systems typically include at least two antennas to transmit and receive radar (e.g., EM) signals. Many vehicle-based systems require high resolution in terms of range, Doppler frequency, and angle. These systems also require the accurate differentiation of multiple targets with similar ranges or Doppler frequencies. Design engineers often address these requirements by including more antenna channels in the radar system. For example, some automotive radar systems operate as MIMO radars to increase the number of channels and improve angular resolution. A MIMO radar system with three transmit channels and four receive channels can form a virtual array (also known as a "synthetic array") of twelve channels. Utilizing the additional channels, MIMO radar systems can operate with improved angular resolution, relying on a flexible physical layout that is inexpensive and may require fewer hardware components than traditional non-MIMO radar systems.

[0017] MIMO radar systems typically use orthogonal waveforms to transmit and receive independent orthogonal EM signals, and to identify or separate different channels. Radar systems can implement orthogonal waveforms in various ways, including using time-division multiplexing (TDM), FDM, and coded multiplexing (CM) techniques. However, each orthogonal waveform technique has its associated advantages and disadvantages.

[0018] For example, FDM technology typically places signals from transmit channels into different frequency bands by adding a frequency offset to the transmitted signal. Such techniques generally operate in the fast time (range) domain, introducing range-dependent phase shifts between channels and reducing range coverage. Due to the increased intermediate frequency bandwidth, FDM technology may also require higher sampling rates.

[0019] CM (Chirp-to-Chirp) technology enables simultaneous transmission and operation in both the fast time domain (e.g., within the chirp and range domains) and the slow time domain (e.g., chirp-to-chirp, Doppler domain). CM typically recovers a signal matching the current encoding by suppressing energy from other encoded signals. The distributed EM energy left from the suppressed signal is generally considered residual energy or noise and limits the dynamic range of the radar system. A smaller dynamic range limits the radar system's ability to distinguish between smaller and larger objects.

[0020] Some TDM techniques do not support simultaneous transmission. Instead, individual transmitters transmit sequentially, resulting in less interference between transmission channels and achieving maximum orthogonality. However, such techniques typically do not offer the signal-to-noise ratio advantages achieved with simultaneous transmission (e.g., FDM and CM techniques) and may lead to Doppler blurring between channels.

[0021] Previous techniques, including those described above, typically did not provide sufficient differentiation between channels, resulting in a lower signal-to-noise ratio. In contrast, this document describes techniques and systems for providing radar systems that utilize FDM technology with polyphase shifters to achieve simultaneous transmission. In this way, the described techniques and systems support simultaneous transmission from multiple transmitters with accurate recovery and no Doppler ambiguity. For example, a radar system for a vehicle includes multiple transmitters, multiple receivers, multiple polyphase shifters, and a processor. The transmitters can transmit EM signals in an FDM scheme. The receivers can receive EM signals, comprising multiple channels, reflected by one or more objects. The polyphase shifters can introduce at least three potential phase shifts into the transmitted EM signals, the received EM signals, or both. The polyphase shifters are operatively connected to the transmitters, receivers, or a combination of both. The processor can control the polyphase shifters to introduce phase shifts. The processor can also divide the Doppler spectrum of the received EM signals into multiple sectors representing corresponding frequency ranges. Each channel is associated with a corresponding sector. The processor can use the incoherent integration of the received EM signals across sectors to determine potential detection of objects. The processor can then determine the actual detection. In this way, simultaneous transmission from multiple transmitters is supported, with accurate recovery and no Doppler blurring. Accurate recovery is possible by avoiding interference between channels. The described FDM technique avoids blurring by identifying each channel without additional information.

[0022] This example is just one illustration of the techniques and systems used in radar systems employing slow time-frequency division multiplexing with multiphase shifters. Other examples and implementations are described in this document.

[0023] Operating environment

[0024] Figure 1 An example environment 100 is shown in which the radar system 104 can be used with an FDM utilizing a multiphase shifter 116, according to the technology of this disclosure. In the depicted environment 100, the radar system 104 is mounted to or integrated into a vehicle 102 traveling on a road 106. Within a field of view 108, the radar system 104 can detect one or more objects 110 in the vicinity of the vehicle 102.

[0025] Radar system 104 can detect one or more objects 110 in the vicinity of vehicle 102. Although shown as a car, vehicle 102 can represent other types of motorized vehicles (e.g., cars, automobiles, trucks, motorcycles, buses, tractors, semi-trailers), non-motorized vehicles (e.g., bicycles), rail vehicles (e.g., trains), water vehicles (e.g., boats), aircraft (e.g., airplanes), or spacecraft (e.g., satellites). Typically, manufacturers can mount radar system 104 to any mobile platform, including mobile machinery or robotic equipment.

[0026] In the depicted implementation, radar system 104 is mounted on the front of vehicle 102 and illuminates object 110. Radar system 104 can detect object 110 from any external surface of vehicle 102. For example, vehicle manufacturers can integrate radar system 104 into bumpers, side mirrors, headlights, taillights, or any other internal or external location where object 110 needs to be detected. In some cases, vehicle 102 includes multiple radar systems 104, such as a first radar system 104 and a second radar system 104 providing a larger field of view 108. Generally, vehicle manufacturers can design the placement of radar systems 104 to provide a specific field of view 108 encompassing a region of interest. Example fields of view 108 include 360-degree fields of view, one or more 180-degree fields of view, one or more 90-degree fields of view, etc., which can overlap or be combined to form a field of view 108 of a specific size.

[0027] Object 110 is made of one or more materials that reflect radar or EM signals. Depending on the application, object 110 may represent a target of interest. In some cases, object 110 may be a moving object (e.g., another vehicle) or a stationary object (e.g., a roadside sign, road obstacle, debris). Depending on the application, object 110 may represent a target of interest, which vehicle 102 can use to safely navigate on road 106.

[0028] Radar system 104 emits EM radiation by transmitting EM signals or waveforms via antenna elements. For example, in environment 100, radar system 104 can detect and track object 110 by transmitting and receiving one or more EM signals. For example, radar system 104 can transmit EM signals between 100 and 400 GHz, between 4 and 100 GHz, or between approximately 70 and 80 GHz.

[0029] Radar system 104 may be a MIMO radar system capable of matching reflected EM signals to a corresponding object 110. Radar system 104 may also operate as a conventional radar system independent of MIMO technology. Radar system 104 may include a transmitter 112 for transmitting EM signals. Radar system 104 may also include a reflective version of a receiver 114 for receiving EM signals. Transmitter 112 includes one or more components, including an antenna or antenna element, for transmitting EM signals. Receiver 114 includes one or more components, including an antenna or antenna element, for detecting reflected EM signals. Transmitter 112 and receiver 114 may be integrated together on the same integrated circuit (e.g., a transceiver integrated circuit) or separately on different integrated circuits. In other implementations, radar system 104 does not include separate antennas, but transmitter 112 and receiver 114 each include one or more antenna elements.

[0030] Radar system 104 may also include a polyphase shifter 116. The polyphase shifter 116 is associated with and operatively connected to transmitter 112, receiver 114, or both. In some applications, the polyphase shifter 116 can apply a phase shift to one or more signal pulses of an EM signal transmitted by transmitter 112. In other implementations, the polyphase shifter 116 can apply a phase shift to one or more signal pulses of a reflected EM signal received by receiver 114. In still other implementations, the polyphase shifter 116 can apply a phase shift to both the transmitted and received EM signals.

[0031] The radar system 104 also includes one or more processors 118 (e.g., energy processing units) and a computer-readable storage medium (CRM) 120. The processor 118 may be a microprocessor or a system-on-a-chip. The processor 118 can execute instructions stored in the CRM 120. For example, the processor 118 can process EM energy received by the receiver 114 and use a spectrum analysis module 122 and an incoherent integrator 124 to determine the position of object 110 relative to the radar system 104. The processor 118 can also detect various characteristics of object 110 (e.g., range, target angle, rate of change of range, velocity). The processor 118 may include instructions or be configured to control the transmitter 112, receiver 114, and multiphase shifter 116. The processor 118 can also generate radar data for at least one vehicle system. For example, the processor 118 can control an autonomous or semi-autonomous driving system of vehicle 102 based on processed EM energy from the receiver 114.

[0032] The spectrum analysis module 122 allows multiple channels in the received EM signal to resolve Doppler ambiguity between the received EM signals. Specifically, the spectrum analysis module 122 can divide the Doppler spectrum of the received EM signal into several sectors. Each sector represents a corresponding frequency range within the Doppler spectrum. For example, the spectrum analysis module 122 can generate more sectors than the number of channels and make the sector sizes equal. As another example, the spectrum analysis module 122 can generate the same number of sectors as the number of channels and make the sector sizes unequal (e.g., each sector has a different frequency width). As yet another example, the spectrum analysis module 122 can generate the same number of sectors as the number of channels and determine the sector sizes to have a subset of sectors of equal size and another subset of sectors of unequal size. See detailed implementation details. Figures 9 to 11 The generation of sectors and the association between channels and sectors are described in more detail. The radar system 104 can implement the spectrum analysis module 122 as instructions in the CRM 120, hardware, software, or a combination thereof executed by the processor 118.

[0033] The incoherent integrator 124 can process the EM energy received by the receiver 114 to identify the object 110 and resolve Doppler ambiguity associated with the object 110 within the field of view 108 of the radar system 104. The incoherent integrator 124 can use several schemes to reject aliased detection and resolve Doppler ambiguity. Schemes used by the incoherent integrator 124 may include single-channel detection and dealiasing, circular shift and minimum analysis, summation and carrier knowledge, sector-based integration and maximum analysis, and circular shift and minimum and maximum analysis, as shown in reference... Figures 12 to 17 In more detail, the radar system 104 may implement the incoherent integrator 124 as instructions in the CRM 120, hardware, software, or a combination thereof executed by the processor 118.

[0034] The described radar system 104 facilitates simultaneous transmission of multiple transmitter channels in a MIMO radar system with a polyphase shifter 116. The described aspects of FDM utilizing the polyphase shifter support simultaneous transmission from multiple transmitters 112 with accurate recovery and no Doppler ambiguity. Accurate recovery is possible because interference between channels is avoided using a spectrum analysis module 122. Doppler ambiguity is resolved using an incoherent integrator 124 to reject aliasing detection.

[0035] As an example environment Figure 1The diagram illustrates a vehicle 102 traveling on a road 106. A radar system 104 detects an object 110 in front of the vehicle 102. The radar system 104 may define a coordinate system with an x-axis (e.g., in the forward direction along the road 106) and a y-axis (e.g., perpendicular to the x-axis and along the surface of the road 106), and in some cases, further define a z-axis (e.g., perpendicular to the xy-plane defined by the x-axis and y-axis). A transmitter 112 of the radar system 104 may emit an EM signal in front of the vehicle 102. The object 110 may reflect the emitted EM signal as a reflected EM signal. A receiver 114 may detect the reflected EM signal.

[0036] Vehicle 102 may also include at least one vehicle system, such as a driver assistance system, autonomous driving system, or semi-autonomous driving system, that relies on data from radar system 104. Radar system 104 may include an interface that interfaces with the vehicle system that relies on the data. For example, processor 118 outputs a signal based on EM energy received by receiver 114 via this interface.

[0037] Typically, automotive systems use radar data provided by radar system 104 to perform functions. For example, a driver assistance system may provide blind spot monitoring and generate an alert indicating a potential collision with object 110 detected by radar system 104. In such implementations, radar data from radar system 104 indicates when changing lanes is safe or unsafe. An autonomous driving system may move vehicle 102 to a specific location on road 106 while avoiding a collision with object 110 detected by radar system 104. The radar data provided by radar system 104 can provide information about the distance to and position of object 110, enabling the autonomous driving system to perform emergency braking, lane changes, or adjust the speed of vehicle 102.

[0038] Figure 2 An example configuration of a radar system using an FDM utilizing a multiphase shifter within a vehicle 102, according to the technology of this disclosure, is shown. The vehicle 102 may include a driving system 206, including an autonomous driving system 208 or a semi-autonomous driving system 210, which uses radar data from the radar system 104 to control the vehicle 102. (See reference...) Figure 1 As described, the vehicle 102 may include a radar system 104.

[0039] The vehicle may also include one or more sensors 202, one or more communication devices 204, and a driving system 206. Sensors 202 may include position sensors, cameras, lidar systems, or combinations thereof. For example, a position sensor may include a positioning system capable of determining the position of vehicle 102. A camera system may be mounted on or near the front of vehicle 102. The camera system may capture photographic images or videos of road 106. In other implementations, a portion of the camera system may be mounted in a rearview mirror of vehicle 102 to have a field of view of road 106. In yet another implementation, the camera system may project a field of view from any external surface of vehicle 102. For example, a vehicle manufacturer may integrate at least a portion of the camera system into a side mirror, bumper, roof, or any other internal or external location where the field of view includes road 106. The lidar system may use electromagnetic signals to detect objects 110 (e.g., other vehicles) on road 106. Data from the lidar system may be provided as input to a spectrum analysis module 122 or an incoherent integrator 124. For example, a lidar system can determine the speed of vehicles in front of vehicle 102 or nearby vehicles traveling in the same direction as vehicle 102.

[0040] Communication device 204 may be a radio frequency (RF) transceiver for transmitting and receiving RF signals. The transceiver may include one or more transmitters and receivers, which may be integrated together on the same integrated circuit (e.g., a transceiver integrated circuit) or separately on different integrated circuits. Communication device 204 may be used to communicate with: remote computing devices (e.g., servers or computing systems providing navigation information or area speed limit information), nearby structures (e.g., construction zone traffic signs, traffic lights, school zone traffic signs), or nearby vehicles. For example, vehicle 102 may use communication device 204 to wirelessly exchange information with nearby vehicles using vehicle-to-vehicle (V2V) communication. Vehicle 102 may use V2V communication to obtain the speed, position, and heading of nearby vehicles. Similarly, vehicle 102 may use communication device 204 to wirelessly receive information from nearby traffic signs or structures indicating temporary speed limits, traffic congestion, or other traffic-related information.

[0041] The communication device 204 may include a sensor interface and a driving system interface. The sensor interface and the driving system interface may transmit data between the radar system 104 and the driving system 206 via the communication bus of the vehicle 102, for example.

[0042] The vehicle 102 also includes at least one driving system 206, such as an autonomous driving system 208 or a semi-autonomous driving system 210, which relies on data from the radar system 104 to control the operation of the vehicle 102 (e.g., setting a driving speed or avoiding object 110). Typically, the driving system 206 uses data provided by the radar system 104 (particularly the incoherent integrator 124) and / or the sensors 202 to control the vehicle 102 and perform certain functions. For example, the semi-autonomous driving system 210 can provide adaptive cruise control and dynamically adjust the speed of the vehicle 102 based on the presence of object 110 in front of it. In this example, data from the incoherent integrator 124 can identify object 110 and its speed relative to the vehicle 102.

[0043] The autonomous driving system 208 can navigate the vehicle 102 to a specific destination while avoiding objects 110 identified by the incoherent integrator 124 and / or radar system 104. Data about the object 110 provided by the radar system 104 can provide information about the position and / or speed of the object 110, enabling the autonomous driving system 208 to adjust the speed of the vehicle 102.

[0044] Example configuration

[0045] Figure 3 An example concept diagram 300 of a radar system 302 using an FDM employing a multiphase shifter 308 is shown. For example, the radar system 302 could be... Figure 1 and Figure 2 Radar system 104. Conceptual diagram 300 illustrates the components of radar system 302 as different components, but some or all of them can be combined into a smaller subset of different components.

[0046] In the depicted implementation, radar system 302 includes a plurality of transmitters 304, shown as antenna elements in this example, configured to transmit corresponding EM signals. Radar system 302 uses the transmitted EM signals to detect any object 110 within the field of view 108 in the vicinity of vehicle 102. In some implementations, transmitters 304 may transmit linear frequency modulated signals (e.g., chirped signals). In other implementations, transmitters 304 may transmit phase-modulated continuous wave (PMCW) signals or pulsed signals (e.g., unmodulated signals). The transmitted EM signals can be any feasible signal for a radar system. Radar system 302 also includes a plurality of receivers 306, shown as antenna elements in this example, configured to receive reflected EM signals reflected by object 110.

[0047] Radar system 302 includes a processor and a CRM, the processor and CRM can be respectively Figure 1 and Figure 2 The processor 118 and CRM 120 are included. The CRM includes instructions that, when executed by the processor, cause the processor to control the transmitter 304 or the phase shifter 308. For example, the processor can use the spectrum analysis module 122 to control the phase shift applied to or introduced into the transmitted EM.

[0048] In the example shown, radar system 302 includes a voltage-controlled oscillator (VCO) 312 operatively coupled to transmitter 304. VCO 312 provides a base or reference signal for the EM signal transmitted by transmitter 304. Multiple phase shifters 308 are associated with and coupled to transmitter 304 and VCO 312, respectively. In the depicted implementation, phase shifters 308 are operatively coupled to each transmitter 304. In other implementations, phase shifters 308 may be operatively coupled to fewer than each transmitter 304.

[0049] A multiphase shifter 308 can control the phase shift applied to or introduced into one or more EM signal pulses emitted by transmitter 304. Each multiphase shifter 308 has multiple potential output stages (e.g., 4, 8, 16, 32, or 64 stages). For example, a processor can provide a multiphase control signal 310 to the multiphase shifter 308 to control or set the phase stage of each multiphase shifter 308. The multiphase control signal 310 can be a multi-bit signal (e.g., 2-bit, 3-bit, 4-bit, 5-bit, or 6-bit), thus allowing the multiphase shifter 308 to have more than two phase stages. The increased number of potential phase stages provides greater flexibility in the FDM coding scheme applied by radar system 302 than that offered by binary phase shifters. The multiphase control signal 310 can add a progressive phase modulation φ to the emitted EM signal pulse, which shifts the frequency or Doppler frequency of the reflected EM signal by a frequency ω. c The offset frequency ω c Equals the product of 2, π, and phase modulation (e.g., ω). c =2πφ).

[0050] As described above, receiver 306 receives the reflected EM signal. Radar system 302 processes the received EM signal to make one or more determinations relating to object 110 within the field of view 108 of radar system 302. Receiver 306 is operatively coupled to a corresponding low-noise amplifier (LNA) 314. LNA 314 amplifies the received EM signal without significantly reducing the signal-to-noise ratio. LNA 314 is operatively coupled to a corresponding mixer 316, which is coupled to VCO 312. The output of VCO 312 is used as a reference signal and combined with the corresponding received EM signal in mixer 316. Radar system 302 passes the corresponding received EM signals through bandpass filter (BPF) 318 and analog-to-digital converter (ADC) 320 before analyzing them with digital signal processor (DSP) 322. DSP 322 can make one or more determinations relating to object 110, including resolving Doppler ambiguity. BPF 318 allows frequencies within a specific range of the received EM signal to pass through and rejects or attenuates frequencies outside that range. In other implementations, radar system 302 may use additional or different filters, including low-pass or high-pass filters. ADC 320 converts the analog EM signal into a digital signal. DSP 322 may use incoherent integrator 124 to resolve Doppler ambiguity and identify the Doppler frequencies associated with object 110. Although DSP 322 is shown as a component separate from the processor, radar system 302 may include a single processor that controls the transmission of EM signals and makes determinations based on the reception of EM signals.

[0051] Figure 4-1 and Figure 4-2 Further example concept diagrams 400 and 410 are shown for radar systems 402 and 412 using an FDM employing a multiphase shifter 308. For example, radar systems 402 and 412 could be... Figure 1 and Figure 2 Radar system 104. Conceptual diagrams 400 and 410 illustrate the components of radar systems 402 and 412 as different components, but some or all of them can be combined into a smaller subset of different components.

[0052] Radar systems 402 and 412 include those targeting Figure 3The components depicted in radar system 302 are similar to those in other radar systems. For example, radar systems 402 and 412 include a transmitter 304, a receiver 306, a processor, a CRM, a polyphase shifter 308, a VCO 312, an LNA 314, a mixer 316, a BPF 318, an ADC 320, and a DSP 322. The polyphase shifter 308 is operatively coupled to the LNA 314 and the mixer 316 in the receiver paths of radar systems 402 and 412. Figure 4-1 In this configuration, the multiphase shifter 308 is operatively coupled to each receive channel and subsequently operatively coupled to a single down-conversion or analog-to-digital conversion channel. Figure 4-2 In this configuration, a multiphase shifter 308 is operatively coupled to each receive channel, and the receive channel or a subset of the multiphase shifters 308 is subsequently operatively coupled to a down-conversion or analog-to-digital conversion channel. As shown in conceptual diagram 410, for each down-conversion or analog-to-digital conversion channel, the radar system 412 includes two multiphase shifters 308 or receive channels. In other implementations, for each down-conversion or analog-to-digital conversion channel, the radar system 412 may include another number of multiphase shifters 308 or receive channels, thereby generating N receive groups, each with M receive channels.

[0053] The polyphase shifter 308 can also be operatively coupled between other components in the receiver path, including between receiver 306 and LNA 314. The polyphase shifter 308 is not operatively coupled to transmitter 304, but is associated with receiver 306 separately. The polyphase shifter 308 can introduce or apply a phase shift to the received EM signal. Radar system 402 or 412 can combine (e.g., superimpose) the signals received by one or more receivers in receiver 306 before analog-to-digital conversion by ADC 320.

[0054] As described above, each multiphase shifter 308 has multiple potential output stages (e.g., 4, 8, 16, 32, or 64 stages). For example, processor 118 can provide multiphase control signals 310 to multiphase shifters 308 to control or set the phase stages of each multiphase shifter 308. The multiphase control signals 310 can be multi-bit signals (e.g., 2-bit, 3-bit, 4-bit, 5-bit, or 6-bit), thus giving multiphase shifters 308 more than two phase stages. The increased number of potential phase stages provides greater flexibility in the FDM encoding scheme applied by radar systems 402 or 502 to the received EM signal than that offered by binary phase shifters. The multiphase control signals 310 can add a progressive phase modulation φ to the received EM signal pulse, which shifts the frequency or Doppler frequency of the reflected EM signal by an offset frequency ω. c The offset frequency ω cEquals the product of 2, π, and phase modulation (e.g., ω). c =2πφ).

[0055] Figure 5-1 and Figure 5-2 Further example concept diagrams 500 and 510 are shown for radar systems 502 and 512 using an FDM employing a multiphase shifter 308. For example, radar systems 502 and 512 could be... Figure 1 and Figure 2 Radar system 104. Conceptual diagrams 500 and 510 illustrate the components of radar systems 502 and 512 as different components, but some or all of them can be combined into smaller subsets of different components.

[0056] Radar systems 502 and 512 include systems targeting... Figure 3 , Figure 4-1 and Figure 4-2 The radar systems 302, 402, and 412 depict components similar to those in the radar systems. For example, radar systems 502 and 512 include a transmitter 304, a receiver 306, a processor, a CRM, a polyphase shifter 308, a VCO 312, an LNA 314, a mixer 316, a BPF 318, an ADC 320, and a DSP 322. The polyphase shifter 308 is operatively coupled to the transmitter 304 and VCO 312 in the transmit path and to the LNA 314 and mixer 316 in the receive path.

[0057] exist Figure 5-1 In this configuration, the multiphase shifter 308 is operatively coupled to each receive channel and subsequently operatively coupled to a single down-conversion or analog-to-digital conversion channel in the receive path. Figure 5-2 In this configuration, a multiphase shifter 308 is operatively coupled to each receive channel, and the receive channel or a subset of the multiphase shifters 308 is subsequently operatively coupled to a down-conversion or analog-to-digital conversion channel in the receive path. As shown in conceptual diagram 510, for each down-conversion or analog-to-digital conversion channel in the receive path, the radar system 512 includes two multiphase shifters 308 or receive channels. In other implementations, for each down-conversion or analog-to-digital conversion channel in the receive path, the radar system 512 may include another number of multiphase shifters 308 or receive channels, thereby creating N receive groups in the receive path, each receive group having M receive channels.

[0058] In other implementations, the polyphase shifter 308 can be operatively coupled to different components in the transmit and receive paths. In radar systems 502 and 512, the polyphase shifter 308 is associated with both the transmitter 304 and the receiver 306. In the depicted implementation, the polyphase shifter 308 can apply or introduce a phase shift to the transmitted and / or received EM signals.

[0059] As described above, each multiphase shifter 308 has multiple potential output stages (e.g., 4, 8, 16, 32, or 64 stages). For example, processor 118 can provide multiphase control signals 310 to multiphase shifters 308 to control or set the phase stages of each multiphase shifter 308. Multiphase control signals 310 can be multi-bit signals (e.g., 2-bit, 3-bit, 4-bit, 5-bit, or 6-bit), allowing multiphase shifters 308 to have more than two phase stages. In the coding scheme applied by radar system 502 or 512 to the transmitted and / or received EM signals, the increased number of potential phase stages provides greater flexibility than that offered by binary phase shifters. Multiphase control signals 310 can add a progressive phase modulation φ to the transmitted and / or received EM signal pulses, which shifts the frequency or Doppler frequency of the reflected EM signal by an offset frequency ω. c The offset frequency ω c Equals the product of 2, π, and phase modulation (e.g., ω). c =2πφ).

[0060] Figure 6 Figure 600 illustrates an example of an transmitted EM signal using an FDM employing a multiphase shifter. For example, Figure 600 shows a signal transmitted by... Figure 3 The EM signal may be transmitted by transmitter 304 of Figure 5. In other implementations, Figure 600 may show the EM signal received by receiver 306 of Figure 4 or Figure 5. As described above, in other implementations, transmitter 304 may transmit a linear frequency modulated signal (e.g., a chirped signal), a phase modulated continuous wave (PMCW) signal, or a pulse signal (e.g., an unmodulated signal).

[0061] Figure 600 illustrates an example strategy for controlling transmitter 304 and / or receiver 306. For example, the first transmitter in transmitter 304 transmits a first signal pulse 602 based on the operation of VCO 312. The first signal pulse 602 has a first phase, which in this example corresponds to zero degrees. The first phase can be considered as a fundamental phase or a reference phase.

[0062] The second transmitter in transmitter 304 transmits a second signal pulse 604 based on the operation of VCO 312 and the corresponding multiphase shifter 308. The second signal pulse 604 has a second phase that is phase-shifted by φ from the first signal pulse 602. As a result, the second phase is shifted from the first phase by a channel frequency ω equal to 2πφ. c .

[0063] The third transmitter in transmitter 304 transmits a third signal pulse 606 based on the operation of VCO 312 and the corresponding multiphase shifter 308. The third signal pulse 606 has a third phase that is phase-shifted by 2φ from the first signal pulse 602. As a result, the third phase is offset from the first phase by the channel frequency 2ω. c .

[0064] The fourth transmitter in transmitter 304 transmits a fourth signal pulse 608 based on the operation of VCO 312 and the corresponding multiphase shifter 308. The fourth signal pulse 608 has a fourth phase, which is phase-shifted by 3φ from the first signal pulse 602. As a result, the fourth phase is offset from the first phase by 3ω from the channel frequency. c .

[0065] The fifth transmitter in transmitter 304 transmits a fifth signal pulse 610 based on the operation of VCO 312 and the corresponding multiphase shifter 308. The fifth signal pulse 610 has a fifth phase that is phase-shifted by 4φ from the first signal pulse 602. As a result, the fifth phase is offset from the first phase by 4ω from the channel frequency. c .

[0066] The sixth transmitter in transmitter 304 transmits a sixth signal pulse 612 based on the operation of VCO 312 and the corresponding multiphase shifter 308. The sixth signal pulse 612 has a sixth phase, which is phase-shifted by 5φ from the first signal pulse 602. As a result, the sixth phase is offset from the first phase by 5ω from the channel frequency. c .

[0067] Simultaneous transmission of signal pulses, including a phase shift, makes it possible to accurately recover the received EM signal information without Doppler ambiguity. MIMO features can also reduce or eliminate signal-to-noise ratio loss. In other implementations, radar systems can use a hybrid of FDM and CM (e.g., code division multiplexing) schemes to apply the described phase shift to the transmitted EM signal. Radar systems can also use pseudo-random outer codes to apply the described phase shift.

[0068] Figure 7 Figure 700 illustrates an example of a received EM signal, represented by a Doppler chamber, using an FDM radar system employing a multiphase shifter. The radar system can be... Figure 1 and Figure 2 Radar system 104 Figure 3 Radar system 302, Figure 4-1 Radar system 402, Figure 4-2 Radar system 412, Figure 5-1 Radar system 502 or Figure 5-2 The radar system 512.

[0069] The received EM signal corresponds to one of the signal pulses and includes a first peak 702. The first peak 702 has a first amplitude and is centered on a frequency-shifted signal 704, which depends on the Doppler frequency ω. D 706 and frequency shift ω c 708. (See reference...) Figure 6 The frequency shift 708 is proportional to the phase shift introduced by the multiphase shifter 308. The Doppler frequency 706 is related to the relative velocity difference between the object 110 and the radar system 104. In the described radar system 104, the received EM signal may include several peaks associated with a single object 110. (Refer to...) Figures 8 to 17 The described techniques and systems enable radar system 104 to identify the actual peaks associated with object 110 and resolve Doppler ambiguity in the received EM signal.

[0070] Example Method

[0071] Figure 8 An example method 800 for a radar system using an FDM employing a multiphase shifter to determine the Doppler frequency of an object is illustrated. Method 800 is shown as a set of operations (or actions) performed, but is not limited to the order or combination of operations shown herein. Furthermore, any one or more of the operations may be repeated, combined, or recombined to provide other methods. References may be made in the sections discussed below. Figure 1 Environment 100 and Figures 1 to 7 The entities detailed herein are referred to by way of example only. This technology is not limited to being performed by one or more entities. For example, a radar system could be... Figure 1 and Figure 2 Radar system 104 Figure 3 Radar system 302, Figure 4-1 Radar system 402, Figure 4-2 Radar system 412, Figure 5-1 Radar system 502 or Figure 5-2 The radar system 512 determines the Doppler frequency of an object 110 around the vehicle 102.

[0072] At point 802, the EM signal is transmitted in an FDM scheme by multiple transmitters of the radar system. The radar system includes a first number of transmitters. For example, transmitter 304 can transmit the EM signal in an FDM scheme.

[0073] At 804, EM signals reflected by one or more objects are received by multiple receivers of the radar system. The radar system includes a second number of receivers. The received EM signals include a number of channels equal to the product of the number of transmitters (e.g., a first number) and the number of receivers (e.g., a second number). For example, receiver 306 may receive EM signals reflected by object 110. Object 110 may reflect EM signals emitted by transmitter 304. The received EM signals include a third number of channels, equal to the product of the first and second numbers.

[0074] At 806, multiple phase shifters are controlled to introduce a phase shift into the transmitted and / or received EM signals. The multiple phase shifters are operatively connected to multiple transmitters and / or receivers of the radar system. The phase shift includes one of at least three potential phase shifts. For example, phase shifter 308 is operatively connected to transmitter 304 and / or receiver 306. Processor 118 can control phase shifter 308 to introduce a phase shift into the transmitted and / or received EM signals, wherein the phase shift includes one of at least three potential phase shifts. As described above, processor 118 can use a phase control signal 310 to control phase shifter 308. The phase control signal 310 can be a multi-bit signal (e.g., 2-bit, 3-bit, 4-bit, 5-bit, or 6-bit), thereby allowing phase shifter 308 to have more than two phase stages. In encoding schemes applied to transmitted and / or received EM signals, the increased number of potential phase stages provides greater flexibility than that offered by binary phase shifters.

[0075] At 808, the Doppler spectrum of the received EM signal is divided into a fourth number of sectors. Each sector represents a corresponding frequency range within the Doppler spectrum. The number of sectors can be equal to or greater than the number of channels (e.g., a third number). For example, the spectrum analysis module 122 can divide the Doppler spectrum of the received EM signal into sectors. The number and size of the sectors can be selected to avoid a symmetrical radiation pattern between channels in the received EM signal, as shown in reference... Figures 9 to 11 A more detailed description.

[0076] At position 810, each channel of the received EM signal is associated with a corresponding sector within the sector. For example, the spectrum analysis module 122 can associate the channels of the received EM signal with the corresponding sectors within the sector. (Refer to...) Figures 9 to 11 The association between channels and corresponding sectors is described in more detail.

[0077] At position 812, incoherent integration of the received EM signal is performed across sectors using at least one channel of the received EM signal. For example, incoherent integrator 124 can perform incoherent integration of the received EM signal across sectors of the Doppler spectrum. (Reference) Figures 12 to 17 The incoherent integration of the received EM signal is described in more detail.

[0078] At point 814, potential detections for one or more objects are determined based on incoherent integration. Potential detections include one or more actual detections and one or more aliasing detections for the one or more objects. For example, incoherent integrator 124, DSP 322, or processor 118 can determine potential detections for object 110 based on incoherent integration. (Refer to...) Figures 12 to 17 The identification of potential detections for object 110 is described in more detail.

[0079] At point 816, actual detection of one or more objects is determined based on latent detection. For example, an incoherent integrator 124, a DSP 322, or a processor 118 can determine actual detection of object 110 based on latent detection. (Refer to...) Figures 12 to 17 The identification of the actual detection of object 110 is described in more detail.

[0080] At 818, the Doppler frequency associated with each of one or more objects is determined based on actual detection. For example, DSP 322 or processor 118 can determine the Doppler frequency associated with object 110 based on actual detection. (Refer to...) Figures 12 to 17 The identification of potential detections for object 110 is described in more detail.

[0081] Figure 9 An example graphical representation 900 of the association between channels and sectors is shown in a radar system using FDM with multiphase shifters. For example, the radar system could be... Figure 1 and Figure 2 Radar system 104 Figure 3 Radar system 302, Figure 4-1 Radar system 402, Figure 4-2 Radar system 412, Figure 5-1 Radar system 502 or Figure 5-2 The radar system 512.

[0082] The graphical representation 900 shows the energy of the received EM signal on the y-axis and the corresponding Doppler frequency of the received EM signal on the x-axis. The received EM signal includes N channels 902, which in... Figure 9 The peaks are represented by triangular peaks corresponding to the actual detection or aliasing detection within each channel.

[0083] The radar system 104 or spectrum analysis module 122 divides the Doppler spectrum of the received EM signal into M equal sectors 904. Each sector 904 represents a frequency range within the Doppler spectrum of the received EM signal. The radar system 104 or spectrum analysis module 122 selects the number of sectors 904 M to be at least one greater than the number of channels 902 N (e.g., M ≥ N + 1). Typically, the number of sectors 904 M is kept sufficiently small to maintain separation between the channels 902 within the Doppler spectrum. Consider a Doppler spectrum divided into six sectors 904 (e.g., M equals six), and the spectrum analysis module 122 can assign a frequency range of π / 3 or sixty degrees to each sector.

[0084] Radar system 104 or spectrum analysis module 122 associates or places channels 902 in individual sectors, with one channel 902 per sector 904. Because the number N of channels 902 is less than the number M of sectors 904, there are one or more empty sectors 906 without corresponding channels. Empty sectors 906 can be placed at various locations within the Doppler spectrum, including between, before, or after each channel 902. The placement of channels 902 and empty sectors 906 is arranged to avoid forming a symmetrical spectrum, which could cause ambiguity in the detection of the target 110.

[0085] The placement of channel 902 within a sector affects the incoherent integration and dealiasing logic used by radar system 104 and / or incoherent integrator 124. For example, radar system 104 or incoherent integrator 124 may perform incoherent integration over a combination of N sectors 904 (e.g., (To form N+M spectra). The radar system 104 can then form the final incoherent integrated spectrum by taking the maximum value of the N+M spectra at each frequency bin. The radar system 104 can then find the sector corresponding to each object from the combination of the maximum values.

[0086] As another example, radar system 104 or spectrum analysis module 122 can divide the Doppler spectrum into 2 M There are 904 equal sectors, where the number of channels N is less than 2. M But greater than or equal to 2 M-1 (For example, 2) M-1 ≤N<2 M Radar system 104 associates or places channels 902 in separate sectors, where each sector 904 has one channel 902 and has (2 M-N) empty sectors 906. Empty sectors 906 can be placed at various locations within the Doppler spectrum, including between, before, or after each channel 902. If the number of channels 902 N is even, the channels 902 are asymmetrically placed between sectors 904. The radar system 104 can perform incoherent integration (e.g., ...) over N consecutive sectors 904. ) to form 2 M Each spectrum. (See reference...) Figure 15 and Figure 16 In more detail, radar system 104 can then be configured to operate at each frequency compartment with 2 M The maximum value of each spectrum is taken to form the final incoherent integrated spectrum. The radar system 104 can then find the sector corresponding to each object from the combination of the maximum values.

[0087] Figure 10 An example graphical representation 1000 of the association between channels and sectors in a radar system using FDM with multiphase shifters is shown. For example, the radar system could be... Figure 1 and Figure 2 Radar system 104 Figure 3 Radar system 302, Figure 4-1 Radar system 402, Figure 4-2 Radar system 412, Figure 5-1 Radar system 502 or Figure 5-2 The radar system 512.

[0088] The graphical representation 1000 shows the energy of the received EM signal on the y-axis and the corresponding Doppler frequency of the received EM signal on the x-axis. The received EM signal includes N channels 1002, which in... Figure 10 The peaks are represented by triangular peaks corresponding to the actual detection or aliasing detection within each channel.

[0089] Radar system 104 or spectrum analysis module 122 divides the received EM signal into M sectors 1004, which have non-uniform sizes 1006. Sector 1004 represents a frequency range within the Doppler spectrum of the received EM signal. Radar system 104 or spectrum analysis module 122 selects the number M of sectors 1004 to be equal to the number N of channels 1002 (e.g., M = N). Consider dividing the Doppler spectrum into six sectors 1004 (e.g., M equals 6), each sector 1004 will have a different corresponding size 1006 for each sector 1004 (e.g., D1 ≠ D2 ≠ D3 ≠ D4 ≠ D5 ≠ D6). Radar system 104 or spectrum analysis module 122 associates or places channels 1002 in individual sectors 1004, with one channel 1002 per sector 1004. Because each sector 1004 has a different size 1006, the channel 1002 is asymmetrical and avoids Doppler blurring during the detection of the object 110.

[0090] Figure 11 An example graphical representation 1100 of the association between channels and sectors is shown in a radar system using FDM with multiphase shifters. For example, the radar system could be... Figure 1 and Figure 2 Radar system 104 Figure 3 Radar system 302, Figure 4-1 Radar system 402, Figure 4-2 Radar system 412, Figure 5-1 Radar system 502 or Figure 5-2 The radar system 512.

[0091] The graphical representation 1100 shows the energy of the received EM signal on the y-axis and the corresponding Doppler frequency of the received EM signal on the x-axis. The EM signal includes N channels 1102, which in... Figure 11 The peaks are represented by triangular peaks corresponding to the actual detection or aliasing detection within each channel.

[0092] The radar system 104 or spectrum analysis module 122 divides the received EM signal into M sectors 1104, which have a combination of uniform and non-uniform sizes or spacings 1106. In other words, some subsets of sectors 1104 have uniform sizes 1106, and one or more other subsets of 1104 have different sizes 1106. Sector 1104 represents a frequency range within the Doppler spectrum of the EM signal. The radar system 104 or spectrum analysis module 122 selects the number M of sectors 1104 to be equal to the number N of channels 1102 (e.g., M = N). Consider dividing the Doppler spectrum into six sectors 1104 (e.g., M equals six). Sectors 1104-1 and 1104-2 may have a first spacing D1106-1, sector 1104-3 may have a second spacing D2106-2, and sectors 1104-4, 1104-5, and 1104-6 may have a third spacing D3106-3. The radar system 104 or spectrum analysis module 122 associates or places channels 1102 in individual sectors, with one channel 1102 per sector 1104. Due to the combination of uniform and non-uniform sizes 1006, channels 1002 are asymmetrical and Doppler blurring is avoided during the detection of the target 110.

[0093] Figure 12 Example flowchart 1200 shows a radar system that uses FDM with multiphase shifters to perform incoherent integration and determine the actual detection associated with an object. For example, the radar system could be... Figure 1 and Figure 2 Radar system 104 Figure 3 Radar system 302, Figure 4-1 Radar system 402, Figure 4-2 Radar system 412, Figure 5-1 Radar system 502 or Figure 5-2 The radar system 512 determines the actual detection of objects 110 around the vehicle 102.

[0094] At 1202, radar system 104 receives EM energy. For example, receiver 114 of radar system 104 can receive EM energy reflected by object 110. Object 110 can reflect EM energy emitted by transmitter 112. Radar system 104 also divides the Doppler frequencies of the received EM energy into sectors and associates channels with sectors, as shown in reference... Figures 8 to 11 A more detailed description is provided. Figure 1210 illustrates potential detectors 1212, 1214, and 1216 in a three-channel radar system. Figure 1210 shows the relationship between the energy associated with potential detectors 1212, 1214, and 1216 and their corresponding Doppler frequencies.

[0095] At 1204, radar system 104 uses a constant false alarm rate (CFAR) threshold to generate a first logical list of potential detections for the first channel in the channel. The CFAR threshold is used to detect object reflections against a background of noise, clutter, and interference in the received EM signal of a single channel. In this way, the CFAR threshold can be reduced or lower than a typical CFAR threshold because a single channel in the channel is being analyzed. For example, compared to the incoherent integral gain from multiple channels, radar system 104 can use a reduced CFAR to account for gain differences in the received EM signal of a single channel.

[0096] The first logic list indicates potential detectors within corresponding Doppler chambers that include peaks with EM energy greater than the CFAR threshold. In other words, logic detectors (e.g., logic detectors 1220, 1222, and 1224) are identified by any energy peak in the received EM signal greater than the reduced CFAR threshold. The logic list represents Doppler chambers within the Doppler spectrum. Logic detector list 1218 shows logic detector 1220 within a Doppler chamber, which corresponds to the center Doppler frequency of potential detector 1212. Similarly, logic detectors 1222 and 1224 correspond to the center Doppler frequencies of potential detectors 1214 and 1216, respectively.

[0097] At 1206, radar system 104 or incoherent integrator 124 performs one or more cyclic shifts on a first logical list of potential detections based on sectors to generate additional logical lists. The number of cyclic shifts is equal to the number of channels N minus one (e.g., N–1). In the depicted implementation, two cyclic shifts are performed on logical detection list 1218, resulting in logical detection lists 1226 and 1234. Logic detection list 1226 includes logical detections 1228, 1230, and 1232. Logic detection list 1234 includes logical detections 1236, 1238, and 1240.

[0098] At 1208, radar system 104 or incoherent integrator 124 uses a logical AND operator on the logic list to determine or generate a final detection list of actual detections. For example, radar system 104 or incoherent integrator 124 determines the actual detection of object 110 by performing a logical AND operation on logic lists 1218, 1226, and 1234 at each Doppler cell in the logic list. As shown in the final detection list 1242, actual detection 1244 is identified at a specific Doppler cell corresponding to logic detections 1224, 1232, and 1240. By using a single channel and its cyclic shift, radar system 104 can process radar data more quickly.

[0099] Figure 13Another example flowchart 1300 is shown, illustrating a radar system that uses FDM with a multiphase shifter to perform incoherent integration and determine the actual detection associated with an object. For example, the radar system could be... Figure 1 and Figure 2 Radar system 104 Figure 3 Radar system 302, Figure 4-1 Radar system 402, Figure 4-2 Radar system 412, Figure 5-1 Radar system 502 or Figure 5-2 The radar system 512 determines the actual detection of objects 110 around the vehicle 102.

[0100] At 1302, radar system 104 receives EM energy. For example, receiver 114 of radar system 104 can receive EM energy reflected by object 110. Object 110 can reflect EM energy emitted by transmitter 112. Radar system 104 can generate a first EM spectrum of the received EM signal for a first channel in the channel. Radar system 104 also divides the Doppler frequencies of the received EM energy into sectors and associates channels with sectors, as shown in reference... Figures 8 to 11 A more detailed description is provided. Figure 1308 illustrates potential detectors 1310, 1312, and 1314 in a three-channel radar system. Figure 1308 shows the relationship between the energy associated with potential detectors 1310, 1312, and 1314 and their corresponding Doppler frequencies.

[0101] At 1304, radar system 104 performs one or more cyclic shifts on the first EM spectrum based on sectors to generate an additional EM spectrum of the received EM signal. The number of cyclic shifts is equal to the number of channels N minus one (e.g., N–1). In the depicted implementation, two cyclic shifts are performed on graphic figure 1308, resulting in graphic figures 1316 and 1318. Graphic figures 1316 and 1318 illustrate potential detections 1310, 1312, and 1314 at different center Doppler frequencies after the corresponding cyclic shifts. For example, graphic figure 1316 illustrates the cyclic shifts of graphic figure 1308, and graphic figure 1318 illustrates the cyclic shifts of graphic figure 1316.

[0102] At 1306, radar system 104 determines the sum of EM energy levels at each Doppler cell across the first EM spectrum and the additional EM spectrum. For example, radar system 104 can sum across graphs 1308, 1316, and 1318 at each Doppler cell to generate graph 1320. Graph 1320 includes potential detectors 1322, 1328, 1330, 1332, 1334, and 1336. Potential detector 1322 includes the sum of EM energies associated with potential detectors 1310, 1312, and 1314. In this way, the actual location of object 110 within the Doppler spectrum is fully integrated, resulting in a higher gain for potential detector 1322. Aliasing locations (e.g., potential detectors 1328-1338) have relatively lower gains.

[0103] At 1308, radar system 104 uses a CFAR threshold to generate a logical list 1340 of potential detections (e.g., a logical detection list). The CFAR threshold is used to detect object reflections against a background of noise, clutter, and interference in the received EM signal of a single channel. Logic list 1340 indicates potential detections within corresponding Doppler chambers that include peaks with EM energy greater than the CFAR threshold. In other words, logical detections are identified by any energy peak in the received EM signal greater than the reduced CFAR threshold (e.g., logical detections 1342, 1344, 1346, 1348, 1350, 1352, and 1354). The logical list represents a Doppler chamber within the Doppler spectrum. Logical detection list 1340 illustrates the logical detections within the Doppler chambers, which correspond to the center Doppler frequency of each potential detection.

[0104] At 1310, radar system 104 identifies aliasing detections based on the association of each channel in the received EM signal with the corresponding sector, thereby determining the actual detection of object 110. For example, radar system 104 identifies actual detection 1358 in the final detection list 1356. Radar system 104 can recursively select potential detections from preliminary detections as actual final detections and identify potential aliasing locations based on channel placement. The recursive process continues until a final detection is selected that identifies an appropriate number of aliasing detections. By using the sum of cyclic shifts of single-channel data, radar system 104 generates higher gain for actual detections, making it easier to identify actual detections amidst noise, weak signals, and aliasing.

[0105] Figure 14 Another example flowchart 1400 illustrates a radar system that uses FDM with a multiphase shifter to perform incoherent integration and determine the actual detection associated with an object. For example, the radar system could be... Figure 1 and Figure 2 Radar system 104 Figure 3 Radar system 302, Figure 4-1 Radar system 402, Figure 4-2 Radar system 412, Figure 5-1 Radar system 502 or Figure 5-2 The radar system 512 determines the Doppler velocity of an object 110 around the vehicle 102.

[0106] At 1402, radar system 104 receives EM energy. For example, receiver 114 of radar system 104 can receive EM energy reflected by object 110. Object 110 can reflect EM energy emitted by transmitter 112. Radar system 104 can generate a first EM spectrum of the received EM signal for a first channel in the channel. Radar system 104 also divides the Doppler frequencies of the received EM energy into sectors and associates channels with sectors, as shown in reference... Figures 8 to 11 A more detailed description is provided. Figure 1410 illustrates potential detectors 1412, 1414, and 1416 in a single channel of a three-channel radar system. Figure 1410 shows the relationship between the energy associated with potential detectors 1412, 1414, and 1416 and their corresponding Doppler frequencies.

[0107] At 1404, radar system 104 performs one or more cyclic shifts on the first EM spectrum based on sectors to generate an additional EM spectrum of the received EM signal. The number of cyclic shifts is equal to the number of channels N minus one (e.g., N–1). In the depicted implementation, two cyclic shifts are performed on graphic figure 1410, resulting in graphic figures 1418 and 1420. Graphic figures 1418 and 1420 illustrate potential detections 1412, 1414, and 1416 at different center Doppler frequencies after the corresponding cyclic shifts. For example, graphic figure 1418 illustrates the cyclic shifts of graphic figure 1410, and graphic figure 1420 illustrates the cyclic shifts of graphic figure 1418.

[0108] At 1406, radar system 104 determines the minimum EM energy level at each Doppler cell in the EM spectrum across the first EM spectrum and the additional EM spectrum. For example, radar system 104 may take the minimum at each Doppler cell across pattern diagrams 1410, 1418, and 1420 to generate pattern diagram 1422. Pattern diagram 1422 includes potential detection 1424. In this way, the actual location of object 110 within the Doppler spectrum is identified because aliasing detections at the same Doppler cells across each pattern diagram do not appear in each pattern diagram.

[0109] At 1408, radar system 104 generates a final detection list 1426 (e.g., a logical detection list) and determines the actual detection of object 110. The actual detection is determined by whether the minimum EM energy level at the corresponding Doppler chamber is greater than a CFAR threshold. The final detection list 1426 indicates which Doppler chambers identify the actual detection. Any energy peak in graphical representation 1422 that is greater than the CFAR threshold identifies the actual detection (e.g., actual detection 1428). The final detection list 1426 shows the logical detections in the Doppler chambers, which correspond to the center Doppler frequency of each potential detection.

[0110] Figure 15 Another example flowchart 1500 is shown, illustrating a radar system that uses FDM with a multiphase shifter to perform incoherent integration and determine the actual detection associated with an object. For example, the radar system could be... Figure 1 and Figure 2 Radar system 104 Figure 3 Radar system 302, Figure 4-1 Radar system 402, Figure 4-2 Radar system 412, Figure 5-1 Radar system 502 or Figure 5-2 The radar system 512 determines the Doppler velocity of an object 110 around the vehicle 102.

[0111] At 1502, radar system 104 receives EM energy. For example, receiver 114 of radar system 104 can receive EM energy reflected by object 110. Object 110 can reflect EM energy emitted by transmitter 112. Radar system 104 can generate a first EM spectrum of the received EM signal for a first channel in the channel. Radar system 104 also divides the Doppler frequency of the received EM energy into equal-sized sectors and associates channels with sectors, as shown in reference... Figure 9 A more detailed description is provided. Figure 1510 illustrates potential detectors 1520, 1522, and 1524 in a single channel of a three-channel radar system. Figure 1510 shows the relationship between the energy associated with potential detectors 1520, 1522, and 1524 and their corresponding Doppler frequencies.

[0112] At 1504, radar system 104 or incoherent integrator 124 uses the first EM spectrum and determines a sector-based integration of the EM energy for each sector. Radar system 104 or incoherent integrator 124 can perform sector-based integration or summation of the EM energy received by a single channel. The number of sectors integrated together is equal to the number of channels N minus one (e.g., N–1). The number of sector-based integrations is equal to the number of channels N. In the depicted implementation, each sector-based integration comprises three consecutive sectors. For example, for a potential target in sector 1512, radar system 104 integrates the EM energy in sectors 1512, 1514, and 1516 together. For a potential target in sector 1514, radar system 104 integrates the EM energy in sectors 1514, 1516, and 1518. For a potential target in sector 1514, radar system 104 integrates the EM energy in sectors 1516, 1518, and 1512. Furthermore, for potential targets in sector 1518, radar system 104 integrates the EM energy in sectors 1518, 1512, and 1514.

[0113] Figure 1526 illustrates the results of sector-based integration, which includes latent detectors 1528, 1530, 1532, and 1534. In this way, the actual location of object 110 within the Doppler spectrum is obtained with a larger integral, resulting in a higher gain for the corresponding latent detector 1528. Aliasing locations (e.g., latent detectors 1530, 1532, and 1534) have relatively smaller gains.

[0114] At 1506, radar system 104 or incoherent integrator 124 determines the maximum EM energy level of the sector-based integration of the EM energy. For example, radar system 104 may take the maximum value across graph 1526 to generate graph 1536. Graph 1536 includes potential detection 1528. In this way, the actual location of object 110 within the Doppler spectrum is identified because aliasing detection does not obtain the same integration gain as actual detection.

[0115] At 1508, radar system 104 uses a CFAR threshold to generate a final detection list 1538 (e.g., a logical detection list) to determine the actual detections. The final detection list 1538 indicates which Doppler chamber the actual detection is identified in. Any energy peak in graphical representation 1536 greater than the CFAR threshold identifies an actual detection (e.g., actual detection 1540). The final detection list 1538 shows the logical detections in the Doppler chambers, corresponding to the center Doppler frequency of each potential detection.

[0116] Figure 16Another example flowchart 1600 is shown, illustrating a radar system that uses FDM with a multiphase shifter to perform incoherent integration and determine the actual detection associated with an object. For example, the radar system could be... Figure 1 and Figure 2 Radar system 104 Figure 3 Radar system 302, Figure 4-1 Radar system 402, Figure 4-2 Radar system 412, Figure 5-1 Radar system 502 or Figure 5-2 The radar system 512 determines the Doppler velocity of an object 110 around the vehicle 102.

[0117] At 1602, radar system 104 receives EM energy. For example, receiver 114 of radar system 104 can receive EM energy reflected by object 110. Object 110 can reflect EM energy emitted by transmitter 112. Radar system 104 can generate a first EM spectrum of the received EM signal for a first channel in the channel. Radar system 104 also divides the Doppler frequencies of the received EM energy into equal-sized sectors and associates channels with sectors, as shown in reference... Figure 9 A more detailed description is provided in Figure 1612, which illustrates potential detectors 1614, 1616, and 1618 in a single channel of a three-channel radar system. Figure 1612 also shows the relationship between the energy associated with potential detectors 1614, 1616, and 1618 and their corresponding Doppler frequencies.

[0118] At 1604, radar system 104 or incoherent integrator 124 performs one or more cyclic shifts on the first EM spectrum based on sectors to generate an additional EM spectrum of the received EM signal. The number of cyclic shifts is equal to the number of channels N minus one (e.g., N–1). In the depicted implementation, two cyclic shifts are performed on graphic figure 1612, resulting in graphic figures 1620 and 1622. Graphic figures 1620 and 1622 illustrate potential detections 1614, 1616, and 1618 at different center Doppler frequencies after the corresponding cyclic shifts. For example, graphic figure 1620 illustrates the cyclic shifts of graphic figure 1612, and graphic figure 1622 illustrates the cyclic shifts of graphic figure 1620.

[0119] At 1606, radar system 104 or incoherent integrator 124 uses the first EM spectrum and the additional EM spectrum and determines a sector-based integration of the EM energy for each sector. The sector-based integration represents the sum of the EM energy across the first EM spectrum and the additional EM spectrum for the corresponding sector. For example, radar system 104 may sum across graphs 1612, 1620, and 1622 at each Doppler cell to generate graph 1624. Graph 1624 includes potential detectors 1626, 1628, 1630, and 1632. Potential detector 1626 includes the sum of the EM energy associated with potential detectors 1614, 1616, and 1618. In this way, the actual location of object 110 within the Doppler spectrum is fully integrated, resulting in a higher gain for potential detector 1626. Aliased locations (e.g., potential detectors 1628, 1630, and 1632) have relatively low gain.

[0120] At 1608, radar system 104 or incoherent integrator 124 determines the maximum EM energy level based on sector-based integration of the EM energy. For example, radar system 104 may take the maximum value across graph 1624 to generate graph 1634. Graph 1634 includes potential detection 1626. In this way, the actual location of object 110 within the Doppler spectrum is identified because aliasing detection results in a lower total gain.

[0121] At 1610, radar system 104 generates a final detection list 1636 (e.g., a logical detection list) of the actual detections. The final detection list 1636 indicates which Doppler compartments identified the actual detection 1638. The final detection list 1636 shows the logical detections in the Doppler compartments, which correspond to the center Doppler frequency of the actual detection 1638.

[0122] Figure 17 Another example flowchart 1700 illustrates a radar system that uses FDM with a multiphase shifter to perform incoherent integration and determine the actual detection associated with an object. For example, the radar system could be... Figure 1 and Figure 2 Radar system 104 Figure 3 Radar system 302, Figure 4-1 Radar system 402, Figure 4-2 Radar system 412, Figure 5-1 Radar system 502 or Figure 5-2 The radar system 512 determines the Doppler velocity of an object 110 around the vehicle 102. Flowchart 1700 includes the same four operations as flowchart 1600 (e.g., operations 1602, 1604, 1606, and 1608).

[0123] At 1602, radar system 104 receives EM energy. For example, receiver 114 of radar system 104 can receive EM energy reflected by object 110. Object 110 can reflect EM energy emitted by transmitter 112. Radar system 104 can generate a first EM spectrum of the received EM signal for a first channel in the channel. Radar system 104 also divides the Doppler frequencies of the received EM energy into equal-sized sectors and associates channels with sectors, as shown in reference... Figure 9 A more detailed description is provided in Figure 1612, which illustrates potential detectors 1614, 1616, and 1618 in a single channel of a three-channel radar system. Figure 1612 also shows the relationship between the energy associated with potential detectors 1614, 1616, and 1618 and their corresponding Doppler frequencies.

[0124] At 1604, radar system 104 or incoherent integrator 124 performs one or more cyclic shifts on the first EM spectrum based on sectors to generate an additional EM spectrum of the received EM signal. The number of cyclic shifts is equal to the number of channels N minus one (e.g., N–1). In the depicted implementation, two cyclic shifts are performed on graphic figure 1612, resulting in graphic figures 1620 and 1622. Graphic figures 1620 and 1622 illustrate potential detections 1614, 1616, and 1618 at different center Doppler frequencies after the corresponding cyclic shifts. For example, graphic figure 1620 illustrates the cyclic shifts of graphic figure 1612, and graphic figure 1622 illustrates the cyclic shifts of graphic figure 1620.

[0125] At 1606, radar system 104 or incoherent integrator 124 uses the first EM spectrum and the additional EM spectrum and determines a sector-based integration of the EM energy for each sector. The sector-based integration represents the sum of the EM energy across the first EM spectrum and the additional EM spectrum for the corresponding sector. For example, radar system 104 may sum across graphs 1612, 1620, and 1622 at each Doppler cell to generate graph 1624. Graph 1624 includes potential detectors 1626, 1628, 1630, and 1632. Potential detector 1626 includes the sum of the EM energy associated with potential detectors 1614, 1616, and 1618. In this way, the actual location of object 110 within the Doppler spectrum is fully integrated, resulting in a higher gain for potential detector 1626. Aliased locations (e.g., potential detectors 1628, 1630, and 1632) have relatively low gain.

[0126] At 1608, radar system 104 or incoherent integrator 124 determines the maximum EM energy level based on sector-based integration of the EM energy. For example, radar system 104 may take the maximum value across graph 1624 to generate graph 1634. Graph 1634 includes potential detection 1626. In this way, the actual location of object 110 within the Doppler spectrum is identified because aliasing detection results in a lower total gain.

[0127] At 1702, radar system 104 or incoherent integrator 124 determines the minimum EM energy level at each Doppler cell of the EM spectrum. For example, radar system 104 or incoherent integrator 124 may take the minimum value across pattern diagrams 1612, 1620, and 1622 at each Doppler cell to generate pattern diagram 1708. Pattern diagram 1708 includes potential detection 1710. In this way, the actual location of object 110 within the Doppler spectrum is identified because aliasing detections at the same Doppler cells across each pattern diagram do not appear in each pattern diagram.

[0128] At 1704, radar system 104 or incoherent integrator 124 uses a CFAR threshold to generate a preliminary minimum detection list 1712 and a preliminary maximum detection list 1716. The preliminary minimum detection list 1712 includes potential detections 1714. The preliminary maximum detection list 1716 includes potential detections 1718. The CFAR threshold is used to detect object reflections against a background of noise, clutter, and interference in the received EM signal of a single channel. The preliminary minimum detection list 1712 indicates potential detections within the corresponding Doppler chamber of graphic figure 1708, the potential detections including peaks with EM energy greater than the CFAR threshold. The preliminary maximum detection list 1716 indicates potential detections within the corresponding Doppler chamber of graphic figure 1708, the potential detections including peaks with EM energy greater than the CFAR threshold.

[0129] At 1706, radar system 104 uses a logical AND operator on the preliminary minimum detection list 1712 and the preliminary maximum detection list 1716 at each Doppler cell to generate a final detection list 1720 of actual detections. The final detection list 1720 indicates which Doppler cells identified the actual detection 1722. The final detection list 1720 shows the logical detections in the Doppler cells that correspond to the center Doppler frequency of the actual detection 1722.

[0130] Example

[0131] Examples are provided in the following sections.

[0132] Example 1: A radar system comprising: a plurality of transmitters configured to transmit electromagnetic (EM) signals in a frequency division multiplexing (FDM) scheme; a plurality of receivers configured to receive EM signals reflected by one or more objects; a plurality of polyphase shifters operatively connected to the plurality of transmitters, the plurality of receivers, or a combination thereof, the plurality of polyphase shifters configured to introduce at least three potential phase shifts; and a processor configured to control the plurality of polyphase shifters to introduce phase shifts into at least one of the transmitted or received EM signals.

[0133] Example 2: The radar system of Example 1, wherein: a plurality of transmitters include a first number of transmitters; a plurality of receivers include a second number of receivers, the second number being equal to or not equal to the first number; a plurality of multiphase shifters include a third number of multiphase shifters, the third number being equal to the first number, the second number, or the sum of the first number and the second number; and the received EM signal includes a fourth number of channels, the fourth number being equal to the product of the first number and the second number.

[0134] Example 3: The radar system of Example 2, wherein: multiple multiphase shifters are operatively connected to multiple transmitters; and the third number is equal to the first number.

[0135] Example 4: The radar system of Example 2, wherein: multiple multiphase shifters are operatively connected to multiple receivers; and the third number is equal to the second number.

[0136] Example 5: The radar system of Example 2, wherein: a plurality of multiphase shifters are operatively connected to a plurality of transmitters and a plurality of receivers; and a third quantity equals the sum of the first quantity and the second quantity.

[0137] Example 6: The radar system of Example 2, wherein the processor is further configured to: divide the Doppler spectrum of the received EM signal into a fifth number of sectors, the sectors representing corresponding frequency ranges within the Doppler spectrum and being of equal size within the Doppler spectrum, the fifth number being equal to or greater than the fourth number plus one; and associate each channel of the received EM signal with a corresponding sector in the sector, at least one of the sectors not associated with a channel of the received EM signal, the association of channels with sectors being configured to form an asymmetric spectrum.

[0138] Example 7: The radar system of Example 2, wherein the processor is further configured to: divide the Doppler spectrum of the received EM signal into a fourth number of sectors, the sectors representing corresponding frequency ranges within the Doppler spectrum and being of unequal size within the Doppler spectrum; and associate each channel of the received EM signal with a corresponding sector in the sector, the association of the channel with the unequal sector being configured to form an asymmetric spectrum.

[0139] Example 8: The radar system of Example 2, wherein the processor is further configured to: divide the Doppler spectrum of the received EM signal into a fourth number of sectors, the sectors representing corresponding frequency ranges within the Doppler spectrum, a subset of sectors being of equal size within the Doppler spectrum, and another subset of sectors being of unequal size within the Doppler spectrum; and associate each channel of the received EM signal with a corresponding sector within the sector, the association of channels and sectors being configured to form an asymmetric spectrum.

[0140] Example 9: Any of the radar systems in the preceding examples, wherein the processor is further configured to: control a plurality of multiphase shifters to dynamically adjust the phase shift of at least one of the transmitted or received EM signals.

[0141] Example 10: Any of the radar systems in the previous examples, wherein multiple transmitters and multiple receivers are configured to operate as part of a multiple-input multiple-output (MIMO) radar approach.

[0142] Example 11: Any of the radar systems in the previous examples, wherein the radar system is configured for mounting on a vehicle.

[0143] Example 12: A computer-readable storage medium comprising computer-executable instructions, which, when executed, cause a processor of a radar system to: transmit electromagnetic (EM) signals via a plurality of transmitters of the radar system in a frequency division multiplexing (FDM) scheme; receive EM signals reflected by one or more objects via a plurality of receivers of the radar system; and control a plurality of polyphase shifters to introduce a phase shift into at least one of the transmitted or received EM signals, the plurality of polyphase shifters being operatively connected to the plurality of transmitters, the plurality of receivers, or a combination thereof, the introduced phase shift including one of at least three potential phase shifts.

[0144] Example 13: A computer-readable storage medium of Example 12, wherein: a plurality of transmitters include a first number of transmitters; a plurality of receivers include a second number of receivers, the second number being equal to or not equal to the first number; a plurality of multiphase shifters include a third number of multiphase shifters, the third number being equal to the first number, the second number, or the sum of the first number and the second number; and the received EM signal includes a fourth number of channels.

[0145] Example 14: A computer-readable storage medium of Example 13, wherein: a plurality of multiphase shifters are operatively connected to a plurality of transmitters; and a third quantity equals the first quantity.

[0146] Example 15: A computer-readable storage medium of Example 13, wherein: a plurality of multiphase shifters are operatively connected to a plurality of receivers; and a third quantity equals the second quantity.

[0147] Example 16: A computer-readable storage medium of Example 13, wherein: a plurality of multiphase shifters are operatively connected to a plurality of transmitters and a plurality of receivers; and a third quantity is equal to the sum of the first quantity and the second quantity.

[0148] Example 17: A computer-readable storage medium of Example 13, wherein the instructions, when executed, further cause a processor of a radar system to: divide the Doppler spectrum of a received EM signal into a fifth number of sectors, the sectors representing corresponding frequency ranges within the Doppler spectrum and being of equal size within the Doppler spectrum, the fifth number being equal to or greater than a fourth number plus one; and associate each channel of the received EM signal with a corresponding sector in the sector, at least one of the sectors not associated with a channel of the received EM signal, the association of channels with sectors being configured to form an asymmetric spectrum.

[0149] Example 18: A computer-readable storage medium of Example 13, wherein the instructions, when executed, further cause a processor of a radar system to: divide the Doppler spectrum of a received EM signal into a fourth number of sectors, the sectors representing corresponding frequency ranges within the Doppler spectrum and being of unequal size within the Doppler spectrum; and associate each channel of the received EM signal with a corresponding sector in the sector, the association of the channels with the unequal sectors being configured to form an asymmetric spectrum.

[0150] Example 19: A computer-readable storage medium of Example 13, wherein the instructions, when executed, further cause a processor of a radar system to: divide the Doppler spectrum of a received EM signal into a fourth number of sectors, each sector representing a corresponding frequency range within the Doppler spectrum, a subset of sectors being of equal size within the Doppler spectrum, and another subset of sectors being of unequal size within the Doppler spectrum; and associate each channel of the received EM signal with a corresponding sector in the sector, at least one of the sectors not being associated with a channel of the received EM signal, the association of channels with sectors being configured to form an asymmetric spectrum.

[0151] Example 20: A method comprising: transmitting an electromagnetic (EM) signal via a frequency division multiplexing (FDM) scheme through a plurality of transmitters of a radar system; receiving an EM signal reflected by one or more objects via a plurality of receivers of the radar system; and controlling a plurality of polyphase shifters to introduce a phase shift into at least one of the transmitted or received EM signals, the plurality of polyphase shifters being operatively connected to the plurality of transmitters, the plurality of receivers, or a combination thereof, the introduced phase shift including one of at least three potential phase shifts.

[0152] Example 21: A radar system comprising: a first number of receivers configured to receive EM signals reflected by one or more objects, the EM signals being transmitted by a second number of transmitters in a frequency division multiplexing (FDM) scheme, the second number being equal to or not equal to the first number, the received EM signals including a third number of channels, the third number being equal to the product of the first number and the second number, at least one of the transmitted or received EM signals including a phase shift between channels; and a processor configured to: divide the Doppler spectrum of the received EM signals into a fourth number of sectors, the sectors representing corresponding frequency ranges within the Doppler spectrum, the fourth number being equal to or greater than the third number; associate each channel of the received EM signals with a corresponding sector within the sectors; perform incoherent integration of the received EM signals across sectors using at least one channel of the received EM signals; determine potential detections of one or more objects based on the incoherent integration, the potential detections including one or more actual detections and one or more aliasing detections of the one or more objects; determine actual detections of the one or more objects based on the potential detections; and determine a Doppler frequency associated with each of the one or more objects based on the actual detections.

[0153] Example 22: The radar system of Example 21, wherein: the phase shift is introduced by a first number of multiphase shifters operably connected to the receiver.

[0154] Example 23: The radar system of Example 21, wherein: the phase shift is introduced by a second number of multiphase shifters operably connected to the transmitter.

[0155] Example 24: The radar system of Example 21, wherein: the phase shift is introduced by a multiphase shifter operably connected to the receiver and the transmitter.

[0156] Example 25: A radar system of any of Examples 21 to 24, wherein: each sector is of equal size in the Doppler spectrum; a fourth quantity is equal to or greater than a third quantity plus one; and each channel of the received EM signal is associated with a corresponding sector in the sector, at least one sector is not associated with a channel of the received EM signal, and the association of channels with sectors is configured to form an asymmetric spectrum.

[0157] Example 26: A radar system of any of Examples 21 to 24, wherein: the sectors are of unequal size in the Doppler spectrum; the fourth quantity is equal to the third quantity; and each channel of the received EM signal is associated with a corresponding sector in the sector, the association of the channels with the unequal sectors being configured to form an asymmetric spectrum.

[0158] Example 27: A radar system of any of Examples 21 to 24, wherein: a subset of sectors are of equal size in the Doppler spectrum, and another subset of sectors are of unequal size in the Doppler spectrum; a fourth quantity is equal to a third quantity; and each channel of the received EM signal is associated with a corresponding sector in the sector, the association of channels and sectors being configured to form an asymmetric spectrum.

[0159] Example 28: A radar system of any of Examples 21 to 27, wherein the processor is further configured to: determine potential detection of one or more objects by generating a first logical list of potential detections for a first channel of a third number of channels using a constant false alarm rate (CFAR) threshold, the potential detections including one or more peaks in a received EM signal having EM energy greater than the CFAR threshold, the first logical list representing Doppler cells in the Doppler spectrum; and performing a specific number of cyclic shifts on the first logical list of potential detections based on sectors to generate a specific number of additional logical lists of potential detections, the specific number being equal to the third number minus one; and determining actual detection of one or more objects by performing a logical AND operation on the first logical list and the additional logical lists of potential detections at each Doppler cell of the logical lists.

[0160] Example 29: A radar system of any one of Examples 21 to 27, wherein the processor is further configured to: determine potential detection of one or more objects by generating a first EM spectrum of a received EM signal for a first channel of a third number of channels; performing a specific number of cyclic shifts on the first EM spectrum based on sectors to generate a specific number of additional EM spectra of the received EM signal, the specific number being equal to the third number minus one; and determining a minimum EM energy level at each Doppler cell of the EM spectrum across the first EM spectrum and the additional EM spectrum; and determining actual detection of one or more objects by determining whether the minimum EM energy level at the corresponding Doppler cell is greater than a constant false alarm rate (CFAR) threshold.

[0161] Example 30: A radar system of any one of Examples 21 to 27, wherein the processor is further configured to: determine potential detection of one or more objects by: generating a first EM spectrum of a received EM signal for a first channel of a third number of channels; performing a specific number of cyclic shifts on the first EM spectrum based on sectors to generate a specific number of additional EM spectra of the received EM signal, the specific number being equal to the third number minus one; determining the sum of EM energy levels at each Doppler compartment of the EM spectrum across the first EM spectrum and the additional EM spectrum; and generating a logical list of potential detections using a constant false alarm rate (CFAR) threshold, the potential detections including one or more peaks with EM energy greater than the CFAR threshold within the sum of EM energy levels, the logical list representing Doppler compartments within the Doppler spectrum; and determining actual detection of one or more objects by identifying one or more aliasing detections based on the association of each channel of the received EM signal with a corresponding sector in the sector.

[0162] Example 31: The radar system of Example 25, wherein the processor is further configured to: determine potential detection of one or more objects by generating a first EM spectrum of a received EM signal for a first channel in a third number of channels; and using the first EM spectrum and for each of a fourth number of sectors, determining a sector-based integral of the EM energy, summing the EM energy of the corresponding sector to the EM energy of a specific number of consecutive sectors, said specific number being equal to the third number minus one; and determining actual detection of one or more objects by determining the maximum EM energy level of the sector-based integral of the EM energy.

[0163] Example 32: The radar system of Example 25, wherein the processor is further configured to: determine potential detection of one or more objects by: generating a first EM spectrum of a received EM signal for a first channel in a third number of channels; performing a specific number of cyclic shifts on the first EM spectrum based on sectors to generate a specific number of additional EM spectra of the received EM signal, the specific number being equal to the third number minus one; and determining a sector-based integral of EM energy for each sector in a fourth number of sectors using the first EM spectrum and the additional EM spectrum, the sector-based integral summing the EM energy of the respective sector across the first EM spectrum and the additional EM spectrum; and determining actual detection of one or more objects by determining the maximum EM energy level of the sector-based integral of the EM energy.

[0164] Example 33: The radar system of Example 25, wherein the processor is further configured to: determine potential detection of one or more objects by generating a first EM spectrum of a received EM signal for a first channel in a third number of channels; performing a specific number of cyclic shifts on the first EM spectrum based on sectors to generate a specific number of additional EM spectra of the received EM signal, the specific number being equal to the third number minus one; and determining a sector-based integral of the EM energy using the first EM spectrum and the additional EM spectrum, and for each sector in a fourth number of sectors, the sector-based integral spanning the first EM spectrum and the additional EM spectrum for the corresponding sector. The EM energies of the regions are summed; the minimum EM energy level at each Doppler cell in the EM spectrum is determined across the first EM spectrum and the additional EM spectrum; a first logical list of potential detections is generated using a constant false alarm rate (CFAR) threshold and a sector-based integral of the EM energy, the first logical list representing the Doppler cells within the Doppler spectrum; and a second logical list of potential detections is generated using the CFAR threshold and the minimum EM energy level at each Doppler cell in the EM spectrum; and the actual detection of one or more objects is determined by performing a logical AND operation on the first and second logical lists of potential detections at each Doppler cell.

[0165] Example 34: A radar system of any of Examples 21 to 33, wherein the transmitter and the receiver operate as part of a multiple-input multiple-output (MIMO) radar method.

[0166] Example 35: A radar system of any one of Examples 21 to 34, wherein the radar system is configured to be mounted on a vehicle.

[0167] Example 36: A computer-readable storage medium comprising computer-executable instructions, which, when executed, cause a processor of a radar system to: receive EM signals reflected by one or more objects via a first number of receivers, the EM signals being transmitted by a second number of transmitters in a frequency division multiplexing (FDM) scheme, the second number being equal to or not equal to the first number, the received EM signals including a third number of channels, the third number being equal to the product of the first number and the second number, at least one of the transmitted EM signals or the received EM signals including a phase shift between channels; divide the Doppler spectrum of the received EM signals into a fourth number of sectors, the sectors representing corresponding frequency ranges within the Doppler spectrum, the fourth number being equal to or greater than the third number; associate each channel of the received EM signals with a corresponding sector in the sector; perform incoherent integration of the received EM signals across sectors using at least one channel of the received EM signals; determine potential detections of one or more objects based on the incoherent integration, the potential detections including one or more actual detections and one or more aliasing detections of the one or more objects; determine actual detections of the one or more objects based on the potential detections; and determine the Doppler frequency associated with each of the one or more objects based on the actual detections.

[0168] Example 37: A computer-readable storage medium of Example 36, wherein: each sector is of equal size within the Doppler spectrum; a fourth number is equal to or greater than a third number plus one; each channel of the received EM signal is associated with a corresponding sector in the sector, at least one sector is not associated with a channel of the received EM signal, and the association of channels and sectors is configured to form an asymmetric spectrum. Furthermore, the computer-readable storage medium includes computer-executable instructions, which, when executed, further cause a processor of a radar system to: determine potential detection of one or more objects by: generating a first EM spectrum of the received EM signal for a first channel of the third number of channels; and using the first EM spectrum and for each sector of the fourth number of sectors, determining a sector-based integral of the EM energy, summing the sector-based integral of the EM energy of the corresponding sector with the EM energy of a specific number of consecutive sectors, the specific number being equal to the third number minus one; and determining actual detection of one or more objects by determining the maximum EM energy level of the sector-based integral of the EM energy.

[0169] Example 38: A computer-readable storage medium of Example 36, wherein: each sector is of equal size in the Doppler spectrum; a fourth quantity is equal to or greater than a third quantity plus one; each channel of the received EM signal is associated with a corresponding sector in the sector, at least one sector is not associated with a channel of the received EM signal, and the association of channels and sectors is configured to form an asymmetric spectrum. Furthermore, the computer-readable storage medium includes computer-executable instructions that, when executed, further cause the processor of the radar system to: determine potential detection of one or more objects by: generating a first EM spectrum of a received EM signal for a first channel in a third number of channels; performing a specific number of cyclic shifts on the first EM spectrum based on sectors to generate a specific number of additional EM spectra of the received EM signal, the specific number being equal to the third number minus one; and determining a sector-based integral of EM energy for each sector in a fourth number of sectors using the first EM spectrum and the additional EM spectrum, the sector-based integral summing the EM energy of the corresponding sector across the first EM spectrum and the additional EM spectrum; and determining actual detection of one or more objects by determining the maximum EM energy level of the sector-based integral of the EM energy.

[0170] Example 39: A computer-readable storage medium of Example 36, wherein: each sector is of equal size within the Doppler spectrum; a fourth number is equal to or greater than a third number plus one; each channel of the received EM signal is associated with a corresponding sector in the sector, at least one of the sectors is not associated with a channel of the received EM signal, and the association of channels and sectors is configured to form an asymmetric spectrum. Furthermore, the computer-readable storage medium includes computer-executable instructions, which, when executed, further cause a processor of a radar system to: determine potential detection of one or more objects by: generating a first EM spectrum of the received EM signal for a first channel of the third number of channels; performing a specific number of cyclic shifts on the first EM spectrum based on sectors to generate a specific number of additional EM spectra of the received EM signal, the specific number being equal to the third number minus one; and determining a sector-based integral of the EM energy using the first EM spectrum and the additional EM spectra and for each sector of the fourth number of sectors, the sector-based integral spanning the first EM spectrum. The EM energy of the corresponding sector is summed with the additional EM spectrum; the minimum EM energy level at each Doppler cell in the EM spectrum is determined across the first EM spectrum and the additional EM spectrum; a first logical list of potential detections is generated using a constant false alarm rate (CFAR) threshold and a sector-based integral of the EM energy, the first logical list representing the Doppler cells within the Doppler spectrum; and a second logical list of potential detections is generated using the CFAR threshold and the minimum EM energy level at each Doppler cell in the EM spectrum; and the actual detection of one or more objects is determined by performing a logical AND operation on the first and second logical lists of potential detections at each Doppler cell.

[0171] Example 40: A method comprising: receiving an EM signal reflected by one or more objects via a first number of receivers, the EM signal being transmitted by a second number of transmitters in a frequency division multiplexing (FDM) scheme, the second number being equal to or not equal to the first number, the received EM signal including a third number of channels, the third number being equal to the product of the first number and the second number, at least one of the transmitted EM signal or the received EM signal including a phase shift between channels; dividing the Doppler spectrum of the received EM signal into a fourth number of sectors, the sectors representing corresponding frequency ranges within the Doppler spectrum, the fourth number being equal to or greater than the third number; associating each channel of the received EM signal with a corresponding sector in the sector; performing an incoherent integration of the received EM signal across the sectors using at least one channel of the received EM signal; determining a potential detection of one or more objects based on the incoherent integration, the potential detection including one or more actual detections and one or more aliasing detections of the one or more objects; determining actual detections of the one or more objects based on the potential detections; and determining a Doppler frequency associated with each of the one or more objects based on the actual detections.

[0172] Conclusion

[0173] While various embodiments of the present disclosure have been described in the foregoing description and illustrated in the accompanying drawings, it should be understood that the present disclosure is not limited thereto, but can be practiced in various ways within the scope of the following claims. It will be apparent from the foregoing description that various modifications can be made without departing from the scope of the present disclosure as defined by the appended claims.

Claims

1. A radar system, comprising: Multiple transmitters configured to transmit electromagnetic signals in a frequency division multiplexing (FDM) scheme; Multiple receivers, the multiple receivers being configured to receive electromagnetic signals reflected by one or more objects; A plurality of multiphase shifters, the plurality of multiphase shifters being operatively connected to the plurality of transmitters, the plurality of receivers, or a combination of the plurality of transmitters and the plurality of receivers, the plurality of multiphase shifters being configured to introduce at least three potential phase shifts; as well as A processor configured to control the plurality of multiphase shifters to introduce a phase shift into at least one of the transmitted or received electromagnetic signals, and to divide the Doppler spectrum of the received electromagnetic signal into a plurality of sectors representing corresponding frequency ranges within the Doppler spectrum, each channel of the received electromagnetic signal being associated with a corresponding sector among the plurality of sectors, the association of the channel with the sector being configured to form an asymmetric spectrum.

2. The radar system as described in claim 1, characterized in that: The plurality of transmitters includes a first number of transmitters; The plurality of receivers includes a second number of receivers, which may or may not be equal to the first number; The plurality of multiphase shifters includes a third number of multiphase shifters, the third number being equal to the first number, the second number, or the sum of the first number and the second number; and The received electromagnetic signals include a fourth number of channels, the fourth number being equal to the product of the first number and the second number.

3. The radar system as described in claim 2, characterized in that: The plurality of multiphase shifters are operatively connected to the plurality of transmitters; and The third quantity is equal to the first quantity.

4. The radar system as described in claim 2, characterized in that: The plurality of multiphase shifters are operatively connected to the plurality of receivers; and The third quantity is equal to the second quantity.

5. The radar system as described in claim 2, characterized in that: The plurality of multiphase shifters are operatively connected to the plurality of transmitters and the plurality of receivers; and The third quantity is equal to the sum of the first quantity and the second quantity.

6. The radar system as described in claim 2, characterized in that, The processor is further configured to: The received electromagnetic signal's Doppler spectrum is divided into a fifth number of sectors, all of equal size within the Doppler spectrum, and this fifth number is equal to or greater than the fourth number plus one; and Each channel of the received electromagnetic signal is associated with a corresponding sector in the sector, wherein at least one of the sectors is not associated with a channel of the received electromagnetic signal, such that the association of the channel with the sector is configured to form the asymmetric spectrum.

7. The radar system as described in claim 2, characterized in that, The processor is further configured to: The Doppler spectrum of the received electromagnetic signal is divided into the fourth number of sectors, wherein the sectors are of unequal size within the Doppler spectrum; and Each channel of the received electromagnetic signal is associated with a corresponding sector in the sector, such that the association of the channel with unequal sectors is configured to form the asymmetric spectrum.

8. The radar system as described in claim 2, characterized in that, The processor is further configured to: The received electromagnetic signal's Doppler spectrum is divided into a fourth number of sectors, where a subset of the sectors is of equal size within the Doppler spectrum, and another subset of the sectors is of unequal size within the Doppler spectrum; and Each channel of the received electromagnetic signal is associated with a corresponding sector in the sector, such that the association between the channel and the sector is configured to form the asymmetric spectrum.

9. The radar system as claimed in claim 1, characterized in that, The processor is further configured to: control the plurality of multiphase shifters to dynamically adjust the phase shift of at least one of the transmitted electromagnetic signal or the received electromagnetic signal.

10. The radar system as claimed in claim 1, characterized in that, The plurality of transmitters and the plurality of receivers are configured to operate as part of a multiple-input multiple-output (MIMO) radar method.

11. The radar system as claimed in claim 1, characterized in that, The radar system is configured for installation on a vehicle.

12. A computer-readable storage medium comprising computer-executable instructions, which, when executed, cause a processor of a radar system to: Electromagnetic signals are transmitted via multiple transmitters of the radar system using a frequency division multiplexing (FDM) scheme; Electromagnetic signals reflected by one or more objects are received via multiple receivers of the radar system; Controlling multiple multiphase shifters to introduce a phase shift into at least one of a transmitted or received electromagnetic signal, said multiple multiphase shifters being operatively connected to said multiple transmitters, said multiple receivers, or a combination of said multiple transmitters and said multiple receivers, the introduced phase shift including one of at least three potential phase shifts; and The Doppler spectrum of the received electromagnetic signal is divided into multiple sectors representing corresponding frequency ranges within the Doppler spectrum. Each channel of the received electromagnetic signal is associated with a corresponding sector among the multiple sectors, and the association between the channel and the sector is configured to form an asymmetric spectrum.

13. The computer-readable storage medium as claimed in claim 12, characterized in that: The plurality of transmitters includes a first number of transmitters; The plurality of receivers includes a second number of receivers, which may or may not be equal to the first number; The plurality of multiphase shifters includes a third number of multiphase shifters, the third number being equal to the first number, the second number, or the sum of the first number and the second number; and The received electromagnetic signals include a fourth number of channels.

14. The computer-readable storage medium as claimed in claim 13, characterized in that: The plurality of multiphase shifters are operatively connected to the plurality of transmitters; and The third quantity is equal to the first quantity.

15. The computer-readable storage medium as claimed in claim 13, characterized in that: The plurality of multiphase shifters are operatively connected to the plurality of receivers; and The third quantity is equal to the second quantity.

16. The computer-readable storage medium as claimed in claim 13, characterized in that: The plurality of multiphase shifters are operatively connected to the plurality of transmitters and the plurality of receivers; and The third quantity is equal to the sum of the first quantity and the second quantity.

17. The computer-readable storage medium as claimed in claim 13, characterized in that, When executed, the instructions further cause the processor of the radar system to: The received electromagnetic signal's Doppler spectrum is divided into a fifth number of sectors, all of equal size within the Doppler spectrum, and this fifth number is equal to or greater than the fourth number plus one; and Each channel of the received electromagnetic signal is associated with a corresponding sector in the sector, wherein at least one of the sectors is not associated with a channel of the received electromagnetic signal, such that the association of the channel with the sector is configured to form the asymmetric spectrum.

18. The computer-readable storage medium as claimed in claim 13, characterized in that, When executed, the instructions further cause the processor of the radar system to: The Doppler spectrum of the received electromagnetic signal is divided into the fourth number of sectors, wherein the sectors are of unequal size within the Doppler spectrum; and Each channel of the received electromagnetic signal is associated with a corresponding sector in the sector, such that the association of the channel with unequal sectors is configured to form the asymmetric spectrum.

19. The computer-readable storage medium as claimed in claim 13, characterized in that, When executed, the instructions further cause the processor of the radar system to: The received electromagnetic signal's Doppler spectrum is divided into a fourth number of sectors, where a subset of the sectors is of equal size within the Doppler spectrum, and another subset of the sectors is of unequal size within the Doppler spectrum; and Each channel of the received electromagnetic signal is associated with a corresponding sector in the sector, wherein at least one of the sectors is not associated with a channel of the received electromagnetic signal, such that the association of the channel with the sector is configured to form an asymmetric spectrum.

20. A method, the method comprising: Electromagnetic signals are transmitted via multiple transmitters in a frequency division multiplexing (FDM) scheme through the radar system; Electromagnetic signals reflected by one or more objects are received via multiple receivers of the radar system; Controlling multiple multiphase shifters to introduce a phase shift into at least one of the transmitted or received electromagnetic signals, the multiple multiphase shifters being operatively connected to the multiple transmitters, the multiple receivers, or a combination of the multiple transmitters and the multiple receivers, the introduced phase shift including one of at least three potential phase shifts; as well as The Doppler spectrum of the received electromagnetic signal is divided into multiple sectors representing corresponding frequency ranges within the Doppler spectrum. Each channel of the received electromagnetic signal is associated with a corresponding sector among the multiple sectors, and the association between the channel and the sector is configured to form an asymmetric spectrum.

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