Synchronization of distributed radar systems using dielectric waveguides

Abstract

A distributed radar system includes a management unit, a plurality of distributed radar units, and a dielectric waveguide network including a plurality of dielectric waveguides coupling the management unit to the plurality of distributed radar units. The management unit is configured to generate a reference signal for synchronizing operation of the plurality of distributed radar units. At least one of the distributed radar units may be configured to generate a digital data signal representing a result of a radar sensing operation of the distributed radar unit, and the dielectric waveguide network may be configured to propagate a representation of the digital data signal to the management unit, and the management unit may be configured to control at least one operation of the distributed radar system based on the digital data signal.

Description

Technical Field

[0001] The present invention relates to synchronization of distributed radar systems using dielectric waveguides. Background Art

[0002] Radar systems typically operate based on the transmission of a signal (often referred to as an "illuminating signal") and the processing of a resulting received signal (often referred to as a "reflected signal"), which represents the signal reflected or scattered by one or more objects in the environment. Coherent radar systems utilize the frequency difference between the illuminating signal and the resulting reflected signal to determine a distance metric for detected objects. The phase difference of the reflected signal between the receiving antennas is used to determine a direction of arrival (DoA) metric for the reflected signal. Therefore, accurate measurement of the frequency and phase differences, and therefore of the distance and DoA metrics, typically depends on accurate synchronization between the generation of the illuminating signal and the processing of the reflected signal.

[0003] Distributed radar systems, such as automotive radar systems based on advanced driver assistance systems (ADAS), utilize multiple radar units for environmental object detection. Achieving sufficient synchronization can be difficult in such distributed radar systems, where ideally the same fully synchronized reference signal, i.e., a reference signal with the same frequency, phase, and timing, would be used to drive the multiple radar units. However, conventional mechanisms for distributing a common reference signal to multiple radar units, such as coaxial cable-based networks or fiber-based networks, typically introduce additional phase noise, which may prevent the distributed system from being sufficiently synchronized to maintain coherence. Furthermore, such conventional approaches can be complex to implement and consume excessive power. These obstacles often lead designers to implement distributed radar systems such that each radar unit generates a local reference signal from a local crystal oscillator or other signal source, resulting in an incoherent distributed radar system. Summary of the Invention

[0004] According to an embodiment, a distributed radar system includes:

[0005] Management unit;

[0006] multiple distributed radar units; and

[0007] a dielectric waveguide network comprising a plurality of dielectric waveguides coupling the management unit to the plurality of distributed radar units;

[0008] wherein the management unit is configured to generate a reference signal for synchronizing operations of the plurality of distributed radar units; and

[0009] The dielectric waveguide network is configured to propagate a representation of the reference signal to each of the plurality of distributed radar units.

[0010] Illustratively, the reference signal includes one of a continuous waveform (CW) signal or a frequency modulated continuous waveform (FMCW) signal.

[0011] Illustratively, the reference signal has a carrier frequency that is equal to a frequency of a radar illumination signal generated by at least one distributed radar unit based on the reference signal.

[0012] Illustratively, each dielectric waveguide comprises a dielectric core at least partially surrounded by at least one cladding.

[0013] Illustratively, the dielectric core is composed of at least one of the following: polytetrafluoroethylene, polyethylene, polypropylene or polystyrene.

[0014] Illustratively, the at least one cladding layer is composed of at least one of a polymer, a metal, or a metal alloy.

[0015] Exemplarily, the management unit is further configured to introduce time stamp information into the reference signal by modulation of the reference signal.

[0016] Illustratively, at least one distributed radar unit of the plurality of distributed radar units is configured to determine the timestamp information from the received representation of the reference signal and to control timing of at least one radar operation of the distributed radar unit based on the timestamp information.

[0017] Illustratively, the dielectric waveguide network has a parallel star topology having a plurality of dielectric waveguides, each dielectric waveguide being terminated at one end by the management unit and at an opposite end by a corresponding distributed radar unit.

[0018] For example, the management unit includes:

[0019] a splitter having an input for receiving the reference signal and a plurality of outputs, each output for providing a representation of the reference signal; and

[0020] a plurality of waveguide interfaces, each waveguide interface coupled to a corresponding one of the plurality of outputs of the splitter and further coupled to a first end of a corresponding one of the plurality of dielectric waveguides, the waveguide interfaces having at least one transmitter for transmitting an analog signal corresponding to the received representation of the reference signal as an electromagnetic signal for propagation to a proximal end of the dielectric waveguide.

[0021] Illustratively, the dielectric waveguide network has a branched star topology including a first dielectric waveguide having one end coupled to the management unit and an opposite end coupled to one of the distributed radar units, and a plurality of second dielectric waveguides, one end of each of the other dielectric waveguides being coupled to the first dielectric waveguide and an opposite end being coupled to a corresponding distributed radar unit.

[0022] For example, the management unit includes:

[0023] A waveguide interface is coupled to the proximal end of the first dielectric waveguide, the waveguide interface having at least one transmitter for transmitting an analog signal corresponding to a representation of the reference signal as an electromagnetic signal to propagate to the proximal end of the dielectric waveguide.

[0024] Illustratively, each distributed radar unit includes:

[0025] a waveguide interface coupled to a proximal end of a corresponding dielectric waveguide of the dielectric waveguide network and comprising at least one transmitter and at least one amplifier to convert an electromagnetic signal received from the dielectric waveguide into a corresponding analog signal; and

[0026] Wherein the distributed radar unit is configured to control at least one radar operation of the distributed radar unit based on a representation of the reference signal generated from the analog signal.

[0027] Example:

[0028] at least one distributed radar unit configured to generate a digital data signal representative of a result of a radar sensing operation of the distributed radar unit;

[0029] The dielectric waveguide network is configured to propagate a representation of the digital data signal to the management unit; and

[0030] The management unit is configured to control at least one operation of the distributed radar system based on the digital data signal.

[0031] According to an embodiment, a vehicle includes an advanced driver assistance system having the aforementioned distributed radar system.

[0032] According to an embodiment, a method in a distributed radar system includes:

[0033] generating a reference signal at the management unit;

[0034] transmitting a representation of the reference signal from the management unit to each of a plurality of distributed radar units via a dielectric waveguide network comprising a plurality of dielectric waveguides; and receiving the representation of the reference signal from the dielectric waveguide network at each distributed radar unit, and controlling one or more radar operations of the distributed radar unit based on the received representation of the reference signal.

[0035] Illustratively, the method further comprises:

[0036] modulating the reference signal at the management unit to introduce time stamp information into the reference signal; and

[0037] Timing of at least one radar operation of the distributed radar unit is controlled at the distributed radar unit based on timestamp information from the received representation of the reference signal.

[0038] Example:

[0039] The dielectric waveguide network has a parallel planet topology having a plurality of dielectric waveguides, each dielectric waveguide terminating at one end with the management unit and at an opposite end with a corresponding distributed radar unit; and

[0040] Transmitting a representation of the reference signal from the management unit to each of the distributed radar units comprises:

[0041] generating a plurality of representations of the reference signal at the management unit; and transmitting electromagnetic signals representing corresponding representations of the reference signal into corresponding dielectric waveguides of the plurality of dielectric waveguides at corresponding waveguide interfaces among the plurality of waveguide interfaces of the management unit using at least one transmitter of the waveguide interface.

[0042] Example:

[0043] The dielectric waveguide network has a branched star topology having a first dielectric waveguide having one end coupled to the management unit and an opposite end coupled to one of the distributed radar units, and a plurality of second dielectric waveguides, each of the other dielectric waveguides having one end coupled to the first dielectric waveguide and an opposite end coupled to a corresponding distributed radar unit; and

[0044] Transmitting a representation of the reference signal from the management unit to each of the distributed radar units comprises:

[0045] An electromagnetic signal representing the reference signal is transmitted at a waveguide interface of the management unit into the first dielectric waveguide using at least one transmitter of the waveguide interface.

[0046] Illustratively, the method further comprises:

[0047] generating, at a distributed radar unit, a digital data signal representing a result of a radar sensing operation of the distributed radar unit;

[0048] propagating a representation of the digital data signal to the management unit via the dielectric waveguide network; and

[0049] At least one operation of the distributed radar system is controlled at the management unit based on the received representation of the digital data signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] By referencing the accompanying drawings, the present disclosure will be better understood and its numerous features and advantages will become apparent to those skilled in the art. The use of the same reference symbols in different drawings indicates similar or identical items.

[0051] Figure 1 is a block diagram of a distributed radar system utilizing a dielectric waveguide network to distribute reference signals, according to some embodiments.

[0052] Figure 2 Different network topologies utilizing dielectric waveguide networks according to some embodiments Figure 1 Block diagram of an alternative implementation of a distributed radar system.

[0053] Figure 3 According to some embodiments Figure 1 and 2 Hardware diagram of the radar management unit of the distributed radar system.

[0054] Figure 4 According to some embodiments Figure 1 and 2 Hardware diagram of the distributed radar unit of the distributed radar system.

[0055] Figure 5 is a diagram showing a method according to some embodiments Figures 1 to 4 A flow chart of a method of operation of a distributed radar system. DETAILED DESCRIPTION

[0056] Some conventional distributed radar systems use coaxial cables or optical fibers to distribute reference signals to multiple radar units. However, coaxial cable-based solutions are generally impractical for transmitting the reference signal at the same carrier frequency as the illumination signal, as they require additional mixers and other circuitry at the receiving radar unit, which can introduce additional, unpredictable phase noise. Fiber-based distributed solutions require electro-optical conversion circuitry on the transmission side and opto-electrical conversion circuitry on the reception side, which increases complexity and power consumption and can be prone to introducing additional phase noise. With the additional phase noise introduced by such conventional solutions, significant uncertainty in the timing is introduced, and as a result, coherence is effectively lost or additional mechanisms, such as phase offset estimation, are used to attempt to mitigate the additional timing uncertainty, increasing the complexity, cost, and inefficiency of such systems. Furthermore, this conversion circuitry cannot typically be manufactured on the same chip or module as other circuitry, requiring a less compact, more complex multi-module approach.

[0057] Figures 1 to 5 Described is a system and method for distributing reference signals in a distributed radar system using a network of one or more dielectric waveguides to transmit reference signals from a management unit to one or more destination radar units. The management unit can be a centralized control unit that does not directly perform any radar illumination or radar sensing operations, or it can be another radar unit that also performs radar operations (i.e., a leader radar unit). In an embodiment, the one or more dielectric waveguides are implemented as a dielectric core (e.g., a polymer optical fiber) and can be surrounded by one or more cladding layers (which can be dielectric or conductive). The dielectric waveguides can utilize total internal reflection (TIR) ​​to transmit electromagnetic (EM) signals along the length of the dielectric core. On the transmit side, the management unit utilizes one or more transmitters and associated circuitry to transmit the reference signals as radio frequency (RF) signals to the transmit side of the dielectric waveguide network. The RF signals are then transmitted along the one or more dielectric waveguides to the one or more radar units via total internal reflection from the corresponding polymer optical fibers. On the receive side of the dielectric waveguide network, the distributed radar units receive the RF signals from the connected dielectric waveguides using their corresponding transmitters / antennas and then utilize the received signals as local reference signals.

[0058] In one embodiment, the reference signal is a continuous waveform (CW) signal, such as a sine wave. In other embodiments, the reference signal is a modulated radar signal, such as a frequency modulated continuous wave (FMCW) signal or a pulsed (or chirped) signal, to be used by the radar unit as an illumination signal. In either approach, the frequency of the reference signal can be at the "radar frequency" of the illumination signal to be generated from the reference signal, or below or above this radar frequency, and then converted to the radar frequency using a frequency multiplier or divider, but due to the higher frequency transmission capability of the dielectric waveguide, the multiplication factor is lower, thereby introducing less potential phase noise. In addition, the waveform of the reference signal can be modulated in either frequency or amplitude, or both, to provide time-stamped signaling, which can be used by the radar unit to synchronize the start time or other time base.

[0059] In at least one embodiment, the dielectric waveguide network utilizes a branched star topology, wherein a single dielectric waveguide is coupled to the management unit, and this single dielectric waveguide branch is in turn connected to a plurality of other dielectric waveguide branches, each of which terminates at a corresponding radar unit. In another embodiment, the dielectric waveguide network utilizes a parallel star topology, wherein a plurality of dielectric waveguides extend between the management unit and a plurality of radar units, wherein each dielectric waveguide terminates at the management unit at one end and at a corresponding radar unit at the other end. In yet other embodiments, the dielectric waveguide network utilizes a ring topology.

[0060] Furthermore, in some embodiments, in addition to utilizing the dielectric waveguide network to distribute reference signals to the radar units, the dielectric waveguide network is also used to transmit data unidirectionally from the radar units to the management unit, or unidirectionally from the management unit to the radar units, or bidirectionally between the radar units and the management unit, such as radar sensing data from the radar units representing results of processing received signals reflected from objects in the environment, or control data from the management unit for use by the radar units in configuring or controlling their operation.

[0061] Figure 1A distributed radar system 100 is shown that employs a dielectric waveguide (DWG) network 102 to distribute reference signaling, according to some embodiments. Distributed radar system 100 (for brevity, "system 100") includes a radar management unit 104 connected to a plurality of distributed radar units 106 (for brevity, "radar units 106") via DWG network 102. For ease of illustration and description, system 100 is depicted as having three radar units 106, enumerated as radar units 106-1, 106-2, and 106-3. However, in other embodiments, two radar units 106 may be employed, or more than two radar units 106 may be employed. Radar unit 106 is configured to operate as a distributed radar unit of system 100 by performing radar operations that include one or both of: an illumination operation by which a radar illumination signal is transmitted into the local environment of radar unit 106 via a corresponding antenna array (e.g., antenna array 110 of radar unit 106-1); or a radar sensing operation in which one or more reflection signals resulting from reflection of the radar illumination signal by one or more objects in the local environment are received via the corresponding antenna array and processed by radar unit 106 to generate digital signaling (i.e., digital data) representing a range metric (e.g., range, velocity, or position) for some or all of the received reflection signals.

[0062] In some embodiments, radar management unit 104 is also one of these radar units 106, but has additional reference signal generation and distribution responsibilities as described herein. In other embodiments, radar management unit 104 operates as a central control unit for system 100 and does not have any direct radar illumination or radar sensing capabilities; that is, radar management unit 104 is not one of distributed radar units 106. In such embodiments, radar management unit 104 operates to control the overall operation of distributed radar units 106 and processes radar sensing data provided by distributed radar units 106 from corresponding radar sensing operations to provide environmental characterization data that can be used by other components (not shown) within system 100. For example, in some embodiments, system 100 is part of an ADAS for an automobile or other vehicle, wherein radar units 106 are distributed around the periphery of the vehicle for detecting objects in the vehicle's local environment using radar illumination / reflection and processing received reflected signals to determine data representing one or more of the range, position, velocity, or shape of one or more objects, and the ADAS further includes one or more processors executing software that utilizes such resulting data to control one or more operations of the vehicle, such as displaying a radar image of detected objects, controlling one or more driving aspects of the vehicle (e.g., emergency braking or adaptive cruise control), etc.

[0063] In an embodiment, system 100 is a coherent distributed radar system in which radar illumination operations and radar sensing operations of radar units 106 are highly correlated with the use of effectively synchronized reference signaling. This synchronized reference signaling is used for both radar illumination signal generation and processing of received reflection signals to extract object range / velocity metrics. Synchronization of this reference signaling is facilitated by transmitting reference signal 108 from radar management unit 104 to each of radar units 106 via DWG network 102. Figure 1 In the illustrated embodiment of FIG, DWG network 102 has a parallel star topology 112, wherein individual dielectric waveguides (DWGs) 114 connect corresponding radar units 106 to radar management unit 104. Thus, in the depicted embodiment, parallel star topology 112 includes DWG 114-1 connecting radar management unit 104 and radar unit 106-1, DWG 114-2 connecting radar management unit 104 and radar unit 106-2, and DWG 114-3 connecting radar management unit 104 and radar unit 106-3. Each DWG 114 is configured to facilitate propagation of electromagnetic (EM) signaling at millimeter wave (mmW) frequencies (30 GHz to 300 GHz) or even higher frequencies with relatively low amplitude loss and low insertion loss.

[0064] As shown by enlarged cross-sections 116 and 118, in some embodiments, each DWG 114 can be implemented in a cable form factor consisting of a dielectric core 120, which can be solid or hollow. In some embodiments, the dielectric core 120 is surrounded by at least one cladding 122 (i.e., a jacket) that partially or completely surrounds the dielectric core 120, while in other embodiments, the cladding is omitted. The dielectric core 120 can be extruded, laminated, cast, or otherwise formed with a solid or hollow core and can be composed of any of a variety of polymers or other suitable dielectric materials, such as polytetrafluoroethylene (PTFE, also known by the trade name "Teflon"), polyethylene (PE), polypropylene (PP), polystyrene (PS), etc. Typically, the material of the dielectric core fiber 120 has a relatively low dielectric constant (Dk) and relatively low insertion loss (e.g., about 5 decibels (dB) or less) and is suitable for propagating EM signals at microwave frequencies or higher (i.e., at the same or similar frequencies used for radar illumination signals). At least one cladding material can be composed of one or more dielectric materials (e.g., open-cell or closed-cell foams, such as expanded PTFE, PP, PE, PS, etc.), one or more metals (e.g., copper (Cu) or silver (Ag)), one or more metal alloys (e.g., copper alloys), or combinations thereof. As shown by cross section 116, DWG 114 can have a circular or oval cross section, wherein dielectric core 120 includes a dielectric core fiber having a circular or otherwise oval cross section and at least one cladding 122 having a similar circular or otherwise oval cross section. Alternatively, as shown by cross section 118, DWG 114 can have a rectangular cross section, wherein dielectric core 120 includes a dielectric core fiber having a rectangular cross section and one or more claddings 122 having a rectangular or oval cross section. An additional aspect of DWG 114 having a rectangular cross section dielectric core 120 is that it can employ either or both orthogonal polarizations for the transmitted signaling. Other cross sections, such as a triangle or another n-sided polygon, can also be employed. One such example embodiment of the DWG 114 comprises a polymer microwave fiber (PMF) DWG.

[0065] exist Figure 1 In the flat star topology 112 of the DWG network 102, the radar management unit 104 distributes the signal via a signal splitter or other signal distribution components (see Figure 3 ) distributes the reference signal 108 (or its repeated representation) to the near end of each corresponding DWG 114. Figure 3Described in more detail, for each of the DWGs 114-1, 114-2, and 114-3, the radar management unit 104 utilizes a corresponding set of one or more transmitters (i.e., antennas) to convert the reference signal 108 into an EM signal that is transmitted into the near end of the corresponding DWG 114, whereby the DWG 114 transmits the EM signal to the far end of the DWG 114 via TIR. Figure 4 Describing in more detail, at the far end of DWG 114 (relative to unit 104), a corresponding radar unit 106 utilizes a set of one or more transmitters (i.e., antennas) to receive EM signals as received reference signals, which are then utilized by radar unit 106 for performing one or both of radar illumination operations or radar sensing operations.

[0066] Briefly turn to Figure 2 , according to various embodiments, shows an alternative implementation of DWG network 102. In the depicted embodiment, DWG network 102 connecting radar management unit 104 to radar units 106 has a branched star topology 212, where DWG network 102 has a single endpoint at radar management unit 104 and a single endpoint at each of radar units 106-1, 106-2, and 106-3. For example, utilizing branched star topology 212, DWG network 102 may include DWG 214-2 connecting radar management unit 104 at one end to radar unit 106-2 at the other end, as well as DWG 214-1 electromagnetically coupled via splitter 216-1 (i.e., a tap) at one end and otherwise coupled to DWG 214-2 and coupled to radar unit 106-1 at the other end, and DWG 214-3 electromagnetically coupled via splitter 216-2 at one end and otherwise coupled to DWG 214-2 and coupled to radar unit 106-3 at the other end. Splitters 216-1 and 216-2 operate to distribute signaling conducted via DWG 214-2 from radar management unit 104 to radar units 106-1 and 106-3, respectively, and to distribute signaling conducted via DWGs 214-1 and 214-3 from radar units 106-1 and 106-3, respectively, to radar management unit 104 via DWG 214-2. It should be noted that while two splitters 216-1 and 216-2 are shown as providing 1-to-3 and 3-to-1 connections, in other embodiments, a single 3-way splitter may be employed to connect both DWG 214-1 and DWG 214-3 to DWG 214-2, and vice versa.

[0067] exist Figure 2In the branched star topology 212, the radar management unit 104 converts the reference signal 108 into an EM signal via one or more transmitters at the near end of the DWG 214-2, and the resulting EM signal is then propagated to the far ends (relative to the radar management unit 104) of the DWGs 214-1, 214-2, and 214-3 via TIR and splitters 216. At each far end, the corresponding radar unit 106 utilizes a set of one or more transmitters (i.e., antennas) to receive the EM signal as a received reference signal, which is then utilized by the radar unit 106 to perform one or both of a radar illumination operation and a radar sensing operation.

[0068] Ideally, the path lengths between radar management unit 104 and each radar unit 106 via DWG network 102 are equal, regardless of the particular topology employed, such that there is no relative time delay in the receipt of a propagated representation of reference signal 108 received at one radar unit 106 relative to the receipt of a propagated representation of reference signal 108 at another radar unit 106. However, in embodiments, various constraints may result in different path lengths between radar management unit 104 and radar units 106. In such cases, if the path length differences result in differences in the timing of receiving the propagated representation of reference signal 108, which may jeopardize satisfactory operation of system 100, radar units 106 may, in some embodiments, employ timing delay circuitry to compensate for the timing differences introduced by the different path lengths, as described below.

[0069] Return to Figure 1 , further describing the operation of system 100. It should be understood that reference signal 108 can take any of a variety of forms. For example, radar management unit 104 can generate reference signal 108 as a continuous wave (CW) signal or a frequency modulated continuous wave (FMCW) signal, as is known in the art. Because the DWGs employed in DWG network 102 are typically capable of mmW frequencies, the carrier frequency (or frequency range) of the CW or FMCW signal can be set to the radar frequency employed by illumination radar units 106 for the radar illumination signals transmitted by these radar units 106. For example, if illumination radar units 106 employ a radar frequency of 77 GHz for their radar illumination signals, radar management unit 104 can generate reference signal 108 as a CW or FMCW signal having a carrier frequency of 77 GHz. In other embodiments, the carrier frequency can be set below or above the radar frequency, in which case radar units 106 can employ a frequency multiplier or divider to convert reference signal 108 to the radar frequency.

[0070] In addition to generating reference signal 108 and distributing the same reference signal 108 across DWG network 102 in a manner that substantially preserves frequency, timing, and phase noise, radar management unit 104 may also utilize modulation of reference signal 108 to convey additional information. For example, coherent distributed radar sensing often relies on accurate timing synchronization in addition to accurate phase / frequency synchronization. For example, the start time of radar illumination signal generation is often synchronized across multiple distributed illumination radar units. Thus, radar management unit 104 may utilize either or both amplitude modulation or frequency modulation to introduce a timestamp into reference signal 108 using any of a variety of known techniques, and radar units 106 may be operable to detect the timestamp present in this additional modulation and synchronize the timing of their respective operations accordingly.

[0071] Furthermore, in addition to the distribution of reference signals 108, DWG network 102 is also used to facilitate data communication. For example, radar data generated by each sensing radar unit 106 may be transmitted as EM data signaling 124 to radar management unit 104 via DWG network 102 using any of a variety of network protocols or data transmission protocols. Furthermore, control or configuration information may be transmitted from radar management unit 104 to one or more radar units 106 as EM data signaling 124 using DWG network 102. For example, DWG network 102 and the associated physical interfaces at radar management unit 104 and radar units 106 may be implemented as the physical (PHY) layer of an Ethernet-based communication network between units 104 and 106.

[0072] Figure 3 Shown according to some embodiments Figure 1 FIG2 illustrates the hardware configuration of radar management unit 104 of system 100. In the depicted example, radar management unit 104 includes digital processing system 302, reference signal generator 304, RF front end 306, replicator 307, and multiple waveguide interfaces 310, one for each parallel DWG 114 of parallel star topology 112, e.g., waveguide interface 310-1 for DWG 114-1, waveguide interface 310-2 for DWG 114-2, and waveguide interface 310-3 for DWG 114-3. In other embodiments having more or fewer DWGs 114 in DWG network 102, radar management unit 104 may implement more or fewer waveguide interfaces 310.

[0073] Digital processing system 302 includes one or more processors, memory, input / output (I / O) devices, and other processing components configured to facilitate the execution of one or more sets of instructions that, when executed, cause the digital processing system to operate to manage radar management unit 104 and the overall operation of system 100. For example, digital processing system 302 may be operable to generate configuration / control data for transmission to radar unit 106 to configure or control its operation, e.g., by specifying radar illumination / sensing parameters, timing parameters, etc. Digital processing system 302 may further be operable to receive radar sensing data from radar unit 106 and process the radar sensing data to control one or more operations of system 100, such as the display of graphical information related to sensed objects in the radar sensing data, to control one or more autonomous driving operations, etc.

[0074] The reference signal generator 304 operates to generate the reference signal 108 and includes any of a variety of circuits or other components known in the art for generating such a reference signal, such as a crystal oscillator, a frequency multiplier or divider, a phase-locked loop (PLL), a delay-locked loop (DLL), etc. The reference signal generator 304 can modify one or more aspects of the reference signal 108, such as the frequency or amplitude (e.g., for the purpose of frequency modulation or amplitude modulation for time stamping), based on a control signal 312 provided by the digital processing system 302. The reference signal generator 304 can also generate a clock signal 315 used by the RF front end 306 for timing / synchronization. For example, the clock signal 315 can be used for timing / synchronization of data signaling transmitted or received via the DWG 114.

[0075] RF front end 306 includes various circuits, as is known in the art, for facilitating conversion of digital data from digital processing system 302 into analog signaling for transmission via DWG 114, and conversion of analog signaling received from DWG 114 into digital data for processing by digital processing system 302. Such circuits may include one or more of a baseband processor, a modem, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), amplifiers, filters, mixers, frequency multipliers, frequency dividers, and the like.

[0076] Replicator 307 includes circuitry, such as an amplifier with multiple replica outputs, configured to receive reference signal 108 as input and output multiple representations of reference signal 108 (i.e., replicas of reference signal 108) as reference signals 308-1, 308-2, and 308-3 having substantially the same frequency, phase noise, and timing. Thus, the circuitry implementing replicator 307 is configured to introduce relatively minimal frequency, phase, and phase noise differences in outputting reference signals 308-1, 308-2, and 308-3 from reference signal 108. Reference signal 308-1 is provided to waveguide interface 310-1, reference signal 308-2 is provided to waveguide interface 310-2, and reference signal 308-3 is provided to waveguide interface 310-3.

[0077] Each of the waveguide interfaces 310-1, 310-2, and 310-3 comprises a physical interface between the radar management unit 104 and the DWGs 114-1, 114-2, and 114-3, respectively. Thus, each waveguide interface 310 comprises a set of one or more transmitters 314 and, in some embodiments, one or more amplifiers 316 (and other circuitry, such as one or more filters) for converting an input analog signal 318 (e.g., the reference signal 308-1 or an analog signal representing digital data) into an EM signal 320, which is then transmitted (or "launched") to the near end of the corresponding DWG 114 and then propagated to the far end via TIR. Waveguide interface 310 may also include a set of one or more transmitters 322 for receiving EM signals propagating from the far end of DWG 114 (i.e., transmitted by corresponding radar unit 106), as well as one or more amplifiers 324 and other circuitry (e.g., one or more filters) to convert the EM signals into analog signals 326 for processing by RF front end 306 (e.g., for conversion from analog signals to digital signals, which are then processed by digital processing system 302). Transmitters 314 for transmitting EM signals and transmitters 322 for receiving EM signals may be the same or different transmitters. Waveguide interface 310 may additionally include physical fasteners to maintain a mechanical connection with corresponding DWG 114 and to properly align the near end of DWG 114 with the set of one or more transmitters 314 and 322.

[0078] Although Figure 3 The hardware configuration of the radar management unit 104 is shown using a parallel star topology 112 for the DWG network 102, but similar methods can be implemented for different topologies for the DWG network 102. For example, for a DWG network Figure 2Instead of the branched star topology 212 , the radar management unit 104 may utilize a single waveguide interface 310 to couple to a single DWG 214 terminating at the radar management unit 104 , and the replicator 307 may be omitted because the reference signal 108 does not need to be split / replicated into multiple synchronized representations.

[0079] Figure 4 Shown according to some embodiments Figure 1 1 shows the hardware configuration of radar unit 106 of system 100. In the depicted example, radar unit 106 includes a digital processing system 402, a radar controller 404, an antenna array 110, an RF front end 406, and a waveguide interface 410. Digital processing system 402 includes one or more processors, memory, I / O devices, and other processing components configured to facilitate the execution of one or more sets of instructions that, when executed, cause digital processing system 402 to operate to manage the overall operation of radar unit 106. For example, digital processing system 402 may be operable to generate configuration / control data for controlling radar controller 404, process radar sensing data from radar controller 404 (e.g., to perform range / speed calculations based on signaling provided by radar controller 404), format digital data for transmission via RF front end 406 and waveguide interface 410 via a corresponding DWG 114 (e.g., DWG 114-1 for radar unit 106-1) (e.g., operating according to the Ethernet protocol as a data link layer and higher layers), etc.

[0080] As is known in the art, radar controller 404 operates to perform one or both of radar illumination operations or radar sensing operations based on configuration information provided by digital processing system 402. The wireless aspects of these operations, such as transmitting radar illumination signals or receiving reflected signals, are performed by antenna array 110, which may include one or more antennas, for example, in a multiple-input multiple-output (MIMO) antenna configuration. The timing and synchronization of these operations are based on received reference signal 412, which in turn is based on a received representation of reference signal 108, as described in more detail below.

[0081] The RF front end 406 includes various circuits, as is known in the art, for facilitating conversion of digital data from the digital processing system 402 into analog signaling for transmission via the corresponding DWG 114, and conversion of analog signaling received from the DWG 114 into digital data for processing by the digital processing system 402. Such circuits may include one or more of a baseband processor, a modem, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), amplifiers, filters, mixers, frequency multipliers, frequency dividers, and the like.

[0082] Waveguide interface 410 comprises a physical interface between radar unit 106 and corresponding DWG 114. Thus, waveguide interface 410 comprises a physical interface for transmitting an input EM signal (e.g., EM signal 320, e.g., EM signal 320) propagating from a far end of DWG 114 (i.e., transmitted from the far end via TIR) to a near end of DWG 114. Figure 3 ) to an analog signal 420. Waveguide interface 410 may also include one or more amplifiers 422 and other circuitry (e.g., one or more filters) and a set of one or more transmitters 424 for receiving analog signals 426 from RF front end 406 and converting analog signals 426 into EM signals, which are transmitted (i.e., transmitted) to the near end of DWG 114 for propagation via TIR to radar management unit 104 at the far end of DWG 114. Analog signals 426 may be, for example, analog representations of digital signals provided by digital processing system 402 or by radar controller 404, and this digital signal may represent, for example, radar sensing data obtained by radar controller 404. Transmitter 424 for transmitting EM signals and transmitter 414 for receiving EM signals may be the same or different transmitters. The waveguide interface 410 may additionally include physical fasteners to maintain a mechanical connection with the corresponding DWG 114 and to properly align the proximal end of the DWG 114 with the set of one or more transmitters 414 and 424 .

[0083] Waveguide interface 410 (or RF front end 406) may further include a timing reference extraction module 428 having circuitry configured to extract reference signal 412 from analog signal 420 when input EM signal 320 represents reference signal 108 generated by radar management unit 104. For example, timing reference extraction module 428 may include one or more amplifiers (which may include amplifier 416), one or more filters, etc. Furthermore, in embodiments where the carrier frequency of reference signal 108 (as represented in received EM signal 320) is not a radar frequency, timing reference extraction module 428 may further include a frequency multiplier or divider to increase or decrease the frequency of extracted reference signal 412 to match the radar frequency used by radar controller 404. Furthermore, as described above, path length differences may exist between various DWGs, so timing reference extraction module 428 may also include circuitry for calibrating or otherwise compensating for time delays introduced by these path length differences between different radar units. Radar controller 404 then utilizes reference signal 412 to control its operations. For example, the frequency and phase of reference signal 412 are used to generate a radar illumination signal transmitted by antenna array 110 and / or to extract range / velocity information from reflected signals received by antenna array 110 in order to generate radar sensing data. Furthermore, as described above, reference signal 108, and therefore the extracted reference signal 412, may include further amplitude modulation or further frequency modulation for inserting timestamp information, and this further modulation may thus be interpreted by radar controller 404 as timestamp information for synchronizing the timing of its radar illumination / sensing operations with other radar units 106 that are simultaneously receiving their own representations of reference signal 108.

[0084] Figure 5 An example method 500 is shown for distributing reference signals in parallel to distributed radar units via a DWG network and returning radar sensing data from the radar units via the same DWG network according to some embodiments. Figures 1 to 4 The method 500 is described in the example context of the system 100 of FIG. 5 , but is not intended to be limited to these particular embodiments. The method 500 begins at block 502, where the reference signal generator 304 of the radar management unit 104 initiates generation of a reference signal 108, which, as described above, may be, for example, a CW signal or an FMCW signal and may have a carrier frequency at, above, or below the radar frequency utilized by the radar unit 106 and may additionally be modulated to include timestamp information or other control information. At block 504, a representation of the reference signal 108 is simultaneously transmitted to each DWG 114 / 214 of the DWG network 102 coupled to the radar management unit 104. For Figure 1The parallel star topology 112 includes generating a plurality of reference signals 308 from the reference signal 108 using a replicator 307, wherein each reference signal 308 is transmitted into a corresponding DWG 114 / 214. Figure 2 2. The radar management unit 104 includes transmitting the reference signal 108 (or a single representation thereof) into the DWG 214 directly coupled to the radar management unit 104. Transmitting the reference signal into the near end of the corresponding DWG 114 / 214 includes using the amplifier, transmitter, and other RF circuitry of the corresponding waveguide interface 310 to convert the reference signal into an EM signal (e.g., EM signal 320), which is injected into the near end of the corresponding DWG 114 / 214 and then propagates toward the far end of the DWG 114 / 214 via TIR.

[0085] At block 506, each radar unit 106 receives the corresponding EM signal via the corresponding DWG 114 / 214, and the transmitter, amplifier, and other circuitry of waveguide interface 410 of radar unit 106 converts the EM signal into an analog signal (e.g., analog signal 420). Timing reference extraction module 428 then extracts reference signal 412 from the analog signal and provides the extracted reference signal 412 to radar controller 404 of radar unit 106.

[0086] At block 508, radar controller 404 performs one or more radar operations that are timed and otherwise synchronized based on reference signal 412. These radar operations may include, for example, transmitting a radar illumination signal generated based on reference signal 412 or receiving one or more reflection signals from one or more objects in the local environment based on the one or more radar illumination signals (block 512). For example, in some configurations, each of radar units 106 is configured to transmit a radar illumination signal and sense reflection signals. For example, in an ADAS system, each of radar units 106-1, 106-2, and 106-3 may be configured to transmit a corresponding radar illumination signal (which may be different from the radar illumination signals transmitted by other radar units 106) and also sense reflection signals not only from its own illumination signal, but also from other radar illumination signals transmitted by other radar units 106. In other configurations, some radar units 106 are operated to transmit only radar illumination signals, while other radar units are operated to sense only reflection signals.

[0087] For example, in an ADAS system, radar unit 106-2 may be configured as an illuminating radar unit only, while radar units 106-1 and 106-3 may be configured as sensing radar units only. For radar sensing operations (block 510), this operation typically includes receiving a reflected signal and comparing the reflected signal to a corresponding transmitted radar illumination signal (e.g., by comparing phase offsets) to determine one or more metrics of the reflecting object, such as distance and / or velocity. Reference signal 412 may be used to control radar operations in various ways. For example, radar controller 404 may generate a radar illumination signal directly from reference signal 412, and thus reference signal 412 may also be used indirectly to determine a distance / velocity metric based on, for example, a phase comparison between the radar illumination signal and the received reflected signal. As another example, as explained above, reference signal 108 may be amplitude modulated or frequency modulated to represent timestamp information, and this modulation is thus present in extracted reference signal 412. Radar controller 404 may then use this timestamp information to control the timing of the start of radar illumination signal transmission (eg, the start of a “chirp”) so that the radar illumination signals of all illumination radar units 106 are time-base synchronized as well as phase and frequency synchronized.

[0088] As explained above, DWG network 102 can additionally be used as a data communication network for transmitting data from radar management unit 104 to radar unit 106 or from radar unit 106 to radar management unit 104. Thus, in embodiments where radar unit 106 performs radar sensing operations, at block 510, radar controller 404 can process the sensed reflection signal (e.g., by determining a phase shift) in light of the radar illumination signal that caused the reflection signal to determine one or more metrics, such as distance or velocity, and digital processing system 402 or radar controller 404 can then convert these metrics into digital data (identified as "radar sensing data"). At block 512, a representation of this radar sensing data is transmitted to radar management unit 104 via DWG network 102. In an embodiment, this process includes digital processing system 402 encapsulating radar sensing data into an appropriate data container (e.g., in an Ethernet frame) for the network protocol used by system 100, and RF front end 406 converting the data container and the radar sensing data contained therein into an analog signal, which is then transmitted as an EM signal by one or more transmitters of waveguide interface 410 into the near end of DWG 114 / 214. The EM signal is then propagated to the far end of DWG network 102 for receipt by radar management unit 104.

[0089] At block 514, the radar management unit 104 receives the EM signal from the DWG network 102 via one or more transmitters at the corresponding waveguide interface 310, and the RF front end 306 converts the resulting analog signal into a digital data signal. At block 516, the digital processing system 302 receives the digital data signal and, in response, takes one or more actions, such as displaying the range / speed information represented in the digital data signal, controlling one or more autonomous driving functions based on the digital data signal, etc.

[0090] In some embodiments, certain aspects of the technology described above can be implemented by one or more processors of a processing system that executes software. The software includes one or more sets of executable instructions stored or otherwise tangibly embodied on a non-transitory computer-readable storage medium. The software may include instructions and certain data that, when executed by one or more processors, manipulate the one or more processors to perform one or more aspects of the technology described above. The non-transitory computer-readable storage medium may include, for example, a magnetic or optical disk storage device, a solid-state storage device such as a flash memory, a cache memory, a random access memory (RAM), or other one or more non-volatile memory devices, and the like. The executable instructions stored on the non-transitory computer-readable storage medium may be in the form of source code, assembly language code, object code, or in the form of other instruction formats that can be interpreted or otherwise executed by one or more processors.

[0091] Computer-readable storage media may include any storage medium or combination of storage media that can be accessed by a computer system during use to provide instructions and / or data to the computer system. Such storage media may include, but are not limited to, optical media (e.g., compact discs (CDs), digital versatile discs (DVDs), Blu-ray discs), magnetic media (e.g., floppy disks, magnetic tapes, or magnetic hard drives), volatile memory (e.g., random access memory (RAM) or cache memory), non-volatile memory (e.g., read-only memory (ROM) or flash memory), or microelectromechanical systems (MEMS)-based storage media. Computer-readable storage media may be embedded in a computing system (e.g., system RAM or ROM), fixedly attached to a computing system (e.g., a magnetic hard drive), removably attached to a computing system (e.g., an optical disc or flash memory based on a universal serial bus (USB)), or coupled to a computer system via a wired or wireless network (e.g., a network accessible storage device (NAS)).

[0092] It should be noted that not all of the activities or elements described above in the overall description are required, a portion of a particular activity or device may not be required, and one or more additional activities may be performed or one or more additional elements may be included in addition to those described. Furthermore, the order in which the activities are listed is not necessarily the order in which they are performed. In addition, the concepts have been described with reference to specific embodiments. However, it will be appreciated by those skilled in the art that various modifications and changes may be made without departing from the scope of the present disclosure as set forth in the claims below. Therefore, the description and drawings should be viewed in an illustrative rather than a restrictive sense, and it is expected that all such modifications are included within the scope of the present disclosure.

[0093] The benefits, other advantages and solutions to problems are described above with respect to specific embodiments. However, these benefits, advantages, solutions to problems, and any features that may make any benefit, advantage or solution appear or become more prominent should not be construed as key, required or essential features of any or all of the claims. Furthermore, the specific embodiments disclosed above are merely illustrative, as the disclosed subject matter may be modified and practiced in different but equivalent manners that would be apparent to those skilled in the art having the benefit of the teachings herein. No limitation is intended to the details of construction or design shown herein, except as described in the appended claims. It is therefore apparent that the specific embodiments disclosed above may be altered or modified, and all such variations are deemed to be within the scope of the disclosed subject matter. Accordingly, the protection sought herein is as set forth in the appended claims.

Claims

1. A distributed radar system, characterized in that: include: Management unit; multiple distributed radar units; as well as a dielectric waveguide network comprising a plurality of dielectric waveguides coupling the management unit to the plurality of distributed radar units; wherein the management unit is configured to generate a reference signal for synchronizing operations of the plurality of distributed radar units; and The dielectric waveguide network is configured to propagate a representation of the reference signal to each of the plurality of distributed radar units.

2. The distributed radar system according to claim 1, wherein: The management unit is further configured to introduce time stamp information into the reference signal by modulation of the reference signal.

3. The distributed radar system according to claim 1, wherein: The dielectric waveguide network has a parallel planet topology with a plurality of dielectric waveguides, each of which terminates at one end with the management unit and at an opposite end with a corresponding distributed radar unit.

4. The distributed radar system according to claim 3, wherein: The management unit includes: a splitter having an input for receiving the reference signal and a plurality of outputs, each output for providing a representation of the reference signal; and a plurality of waveguide interfaces, each waveguide interface coupled to a corresponding one of the plurality of outputs of the splitter and further coupled to a first end of a corresponding one of the plurality of dielectric waveguides, the waveguide interfaces having at least one transmitter for transmitting an analog signal corresponding to the received representation of the reference signal as an electromagnetic signal for propagation to a proximal end of the dielectric waveguide.

5. The distributed radar system according to claim 1, wherein: The dielectric waveguide network has a branched star topology including a first dielectric waveguide having one end coupled to the management unit and an opposite end coupled to one of the distributed radar units, and a plurality of second dielectric waveguides, each of the other dielectric waveguides having one end coupled to the first dielectric waveguide and an opposite end coupled to a corresponding distributed radar unit.

6. The distributed radar system according to claim 5, characterized in that The management unit includes: A waveguide interface is coupled to the proximal end of the first dielectric waveguide, the waveguide interface having at least one transmitter for transmitting an analog signal corresponding to a representation of the reference signal as an electromagnetic signal to propagate to the proximal end of the dielectric waveguide.

7. A vehicle, characterized in that: The vehicle includes an advanced driver assistance system having the distributed radar system according to claim 1 .

8. A method in a distributed radar system, characterized in that: The method comprises: generating a reference signal at the management unit; transmitting a representation of the reference signal from the management unit to each of a plurality of distributed radar units via a dielectric waveguide network comprising a plurality of dielectric waveguides; and The representation of the reference signal is received from the dielectric waveguide network at each distributed radar unit, and one or more radar operations of the distributed radar units are controlled based on the received representation of the reference signal.

9. The method according to claim 8, characterized in that: The dielectric waveguide network has a parallel planet topology having a plurality of dielectric waveguides, each dielectric waveguide terminating at one end with the management unit and at an opposite end with a corresponding distributed radar unit; and Transmitting a representation of the reference signal from the management unit to each of the distributed radar units comprises: generating, at the management unit, a plurality of representations of the reference signal; as well as An electromagnetic signal representing a corresponding representation of the reference signal is transmitted at a corresponding waveguide interface of a plurality of waveguide interfaces of the management unit into a corresponding dielectric waveguide of the plurality of dielectric waveguides using at least one transmitter of the waveguide interface.

10. The method according to claim 8, characterized in that: The dielectric waveguide network has a branched star topology having a first dielectric waveguide having one end coupled to the management unit and an opposite end coupled to one of the distributed radar units, and a plurality of second dielectric waveguides, each of the other dielectric waveguides having one end coupled to the first dielectric waveguide and an opposite end coupled to a corresponding distributed radar unit; and Transmitting a representation of the reference signal from the management unit to each of the distributed radar units comprises: An electromagnetic signal representing the reference signal is transmitted at a waveguide interface of the management unit into the first dielectric waveguide using at least one transmitter of the waveguide interface.

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