Cooperative Compact Radar Target Simulator for Improved Accuracy and Improved Ghost Cancellation

Abstract

To provide a system for emulating a plurality of targets.SOLUTION: A system 100 for testing vehicular radar includes a re-illumination element adapted to receive electromagnetic waves and to transmit response signals. The re-illumination element includes: a plurality of miniature radar target simulators (MRTSs 106), each comprising a receive antenna, a variable gain amplifier (VGA), an in-phase-quadrature (IQ) mixer, a variable attenuator, and a transmit antenna. The MRTSs 106 are disposed in an array comprising rows and columns of the MRTSs 106, and each MRTS 106 of the array is at a lateral distance px and a vertical distance py from an adjacent MRTS 106. An incremental subtended azimuth angle (δφ) and an incremental subtended elevation (δθ) angle are finer than an azimuth resolution specification (φres) and an elevation resolution specification (θres) of a radar device under test (DUT).SELECTED DRAWING: Figure 1A

Description

[Background technology]

[0001] Millimeter waves arise from vibrations at frequencies within the 30 gigahertz (GHz) to 300 gigahertz frequency spectrum. Millimeter-wave (mm-wave) automotive radar is a key technology for existing advanced driver-assistance systems (ADAS) and planned autonomous driving systems. For example, mm-wave automotive radar is used in ADAS to warn of forward and rear-end collisions. Furthermore, mm-wave automotive radar may be used in planned autonomous driving systems to implement adaptive cruise control and autonomous parking, and ultimately for autonomous driving on streets and highways. Millimeter-wave automotive radar has advantages over other sensor systems in that it can operate under most types of weather conditions and during both day and night. The cost of adapting mm-wave automotive radar has fallen to a level that allows it to be deployed on a large scale. As a result, millimeter-wave automotive radars are currently widely used for long-, medium-, and short-range environmental sensing in advanced driver assistance systems, and are likely to be widely used in autonomous driving systems currently under development.

[0002] Actual driving environments in which automotive radars may be deployed can vary greatly, and many such driving environments can be complex. For example, a real driving environment may include numerous objects, and some of the objects encountered in a real driving environment may have complex reflection and diffraction characteristics that affect the echo signals. As a direct result of incorrectly detecting and / or interpreting the echo signals, false alarms or inappropriate reactions may be triggered, or warnings or reactions that should be triggered may not be triggered, which may lead to an accident.

[0003] As a result, automobile manufacturers and automotive radar manufacturers are eager to electronically emulate driving conditions to provide automotive radar systems with optimal accuracy performance.

[0004] Single-target radar emulators are known. However, emulating real-world driving scenarios requires emulating multiple targets. For example, a radar-equipped vehicle may have a car ahead in the same lane, a truck ahead in one lane to the left, a cyclist ahead along the lane divider to the right, and another vehicle attempting to run a red light in cross traffic. Emulating apparent angle of arrival (AoA) using known devices is slow and not scalable to larger numbers due to expensive electronics. Furthermore, most known emulators emulate only an incomplete subset of range, speed, and AoA.

[0005] Therefore, what is needed is a system for emulating multiple targets encountered by a radar system that overcomes at least the shortcomings of known radar emulators discussed above.

[0006] The illustrative embodiments are best understood from the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that the various features are not necessarily drawn to scale. In fact, dimensions may be arbitrarily increased or decreased for clarity of discussion. Wherever applicable and practical, like reference numerals refer to like elements. [Brief explanation of the drawings]

[0007] [Figure 1A] FIG. 1 is a simplified block diagram illustrating a system for testing vehicle radar in accordance with a representative embodiment. [Figure 1B] FIG. 1 is a simplified block diagram of an array of miniature radar target simulators (MRTSs) in accordance with a representative embodiment. [Figure 2] FIG. 1 is a simplified circuit diagram of an MRTS according to a representative embodiment. [Figure 3] FIG. 2 is a simplified block diagram of adjacent MRTSs used to interpolate an emulated target located between the adjacent MRTSs, according to a representative embodiment. [Figure 4A] FIG. 10 illustrates adjacent offset MRTSs useful for suppressing ghost images, according to a representative embodiment. [Figure 4B] FIG. 10 illustrates adjacent offset MRTSs arranged in a curvilinear arrangement and useful for suppressing ghost images, according to a representative embodiment. [Figure 5] FIG. 1 illustrates emulation of a target consisting of a single MRTS, according to a representative embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] In the following detailed description, for purposes of explanation and not limitation, exemplary embodiments disclosing specific details are described to provide a thorough understanding of an embodiment according to the present teachings. Descriptions of known systems, devices, materials, methods of operation, and methods of manufacture may be omitted to avoid obscuring the description of the exemplary embodiments. Nevertheless, systems, devices, materials, and methods within the understanding of those skilled in the art are within the scope of the present teachings and may be used in accordance with the exemplary embodiments. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. Defined terms have meanings commonly understood and accepted in the technical field of the present teachings, in addition to the scientific and technical meaning of the defined term.

[0009] Although terms such as first, second, and third may be used herein to describe various elements or components, it should be understood that these elements or components should not be limited by these terms. These terms are used only to distinguish one element or component from another. Thus, a first element or component discussed below could be referred to as a second element or component without departing from the teachings of the present disclosure.

[0010] The terms used herein are for the purpose of describing particular embodiments only and are not intended to be limiting. As used in this specification and the appended claims, the singular terms "a," "an," and "the" are intended to include both the singular and the plural unless the context clearly dictates otherwise. Furthermore, the terms "comprises" and / or similar terms, as used herein, specify the presence of the referenced feature, element, and / or component, but do not exclude the presence or addition of one or more other features, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0011] Unless otherwise stated, when an element or component is said to be "connected" or "coupled" to another element or component, it is understood that the element or component can be directly connected or coupled to the other element or component, or there may be intervening elements or components. That is, these and similar terms include instances where one or more intervening elements or components may be used to connect the two elements or components. However, when an element or component is said to be "directly connected" to another element or component, this only includes instances where the two elements or components are connected to each other without any intervening or intervening elements or components.

[0012] As described herein with respect to various representative embodiments, a system for testing vehicle radar is disclosed. The system includes a re-illumination element adapted to receive electromagnetic waves and transmit a response signal. The re-illumination element includes a plurality of miniature radar target simulators (MRTSs), each including a receive antenna, a variable gain amplifier (VGA), an in-phase-quadrature (IQ) mixer, a variable attenuator, and a transmit antenna. The MRTSs are arranged in an array including rows and columns of the MRTSs, and each MRTS in the array is spaced a lateral distance p from an adjacent MRTS. x and spaced apart vertically by a distance p y be separated by .direction angle The incremental angle of the angle (δφ) and The increment angle (δθ) of the angle between the upper and lower angles is , the azimuth resolution specification (φ res ) and vertical resolution specifications (θ res ) is finer than

[0013] As described herein with respect to various representative embodiments, a system for testing a vehicle radar is disclosed. The system includes a re-illumination element adapted to receive electromagnetic waves and transmit a response signal. The re-illumination element includes a plurality of miniature radar target simulators (MRTSs), each including a receive antenna, a variable gain amplifier (VGA), an in-phase / quadrature (IQ) mixer, a variable attenuator, and a transmit antenna. The MRTSs are arranged in an array including rows and columns of the MRTSs. The VGAs and variable attenuators are configured to control the emulated radar cross section (RCS) of the target, and the plurality of MRTSs in the array are staggered and displaced from a device under test (DUT).

[0014] As described herein with respect to various representative embodiments, a system for testing a vehicle radar is disclosed. The system includes a re-illumination element adapted to receive electromagnetic waves and transmit a response signal. The re-illumination element includes a plurality of miniature radar target simulators (MRTSs), each of which includes a receive antenna, a variable gain amplifier (VGA), an in-phase / quadrature (IQ) mixer, a variable attenuator, and a transmit antenna. The MRTSs are arranged in an array including rows and columns of the MRTSs, and each MRTS in the array is configured to transmit a radar target signal at a resolution specification (θ ) of the radar device under test (DUT). res ) at a distance p x and spaced apart vertically by a distance p y The system also includes a controller having a memory for storing instructions and a processor for executing those instructions, the controller being configured to control the re-illumination elements and operate the adjacent MRTSs. .direction angle The incremental angle of the angle (δφ) and and the incremental angle of the upper and lower angles ( δθ )teeth , azimuth resolution specification on vehicle radar including multiple targets (φ res ) and is more subtle than the height test.

[0015] Among other advantages, the emulation provided by the system of the present teachings is based on the "coordinated modulation" of the MRTSs described herein, whereby the modulation of the MRTSs arranged in an array to provide a re-illuminator is coordinated to provide angular interpolation as well as suppression of multiple ghost signals, as described more fully herein.

[0016] 1A and 1B are simplified block diagrams illustrating a system 100 for testing vehicle radar according to a representative embodiment. As will be understood by those skilled in the art having the benefit of this disclosure, one promising vehicle radar is an automotive radar used in various capacities in current and emerging automotive applications. It should be emphasized, however, that the vehicle radar testing system 100 described herein is not limited to automotive radar systems, but may also be applied to other types of vehicles, including buses, motorcycles, mopeds (e.g., scooters), and other vehicles in which a vehicle radar system may be used.

[0017] According to an exemplary embodiment, system 100 is prepared to test a radar device under test (DUT) 102. System 100 includes a reilluminator 101 having an array of MRTSs 106. The array of MRTSs 106 in FIG. 1A is two-dimensional, extending in the x- and y-directions according to the coordinate system of FIG. 1A. Accordingly, FIG. 1B illustrates a two-dimensional array of MRTSs 106 from the vantage point of the radar DUT 102 (i.e., in the x- and y-plane of FIG. 1B). As explained more fully below, the MRTSs 106 of system 100 are adapted to emulate targets in one or two dimensions. Moreover, the array of MRTSs 106 of reilluminator 101 can be relatively flat (e.g., in the x- and y-plane as shown in FIG. 1B), curved in an arc along a single row array, or curved in two dimensions in a multiple column and row array.

[0018] The MRTSs 106 of the array are spaced apart at lateral intervals p as shown in FIGS. 1A and 1B. x and vertical spacing p y For reasons explained in more detail below, the lateral spacing p between adjacent MRTSs 106 x teeth ,direction rank Incremental angles of the angle (δφ in Figure 1A) is the azimuth resolution specification (φ res) and the vertical spacing p between adjacent MRTS 106 y teeth ,above under Incremental angles of the angle (δθ, not shown) )but Vertical resolution (θ res ) is chosen to be slightly finer than δφ. According to an exemplary embodiment discussed in more detail below, δφ=φ res / 2 and δθ=θ res / 2.

[0019] As described below with respect to FIG. 2, each of the MRTSs 106 includes a transmit antenna (not shown in FIGS. 1A and 1B) and a receive antenna (not shown in FIGS. 1A and 1B). As described more fully herein, there is one MRTS 106 for each target being emulated. The system also includes a computer 112. The computer 112 illustratively includes a controller 114 as described herein. The controller 114 as described herein may include a combination of a processor 116 and a memory 118 that stores instructions. The processor 116 executes the instructions to implement the processes described herein. To this end, the computer 112 is adapted to control the re-illuminator 101, according to an exemplary embodiment, in addition to controlling the functions of the radar DUT 102. As explained more fully below, instructions stored in memory 118 are executed by processor 116 to modify the signal strength (and therefore power) of a selected MRST 106 by adjusting the drive signal from computer 112 to the MRTS 106, such that a weaker drive signal provides a relatively weaker response emulation signal and a stronger drive signal provides a relatively stronger response emulation signal, in accordance with the present teachings. However, in particular embodiments, the relatively large amplitude and emulation strength (and thereby emulated RCS) of the drive signal to the IQ mixer of the MRTS 106 is adjusted by a VGA. While this approach is preferable to lowering the amplitude of the desired stimulus signal by lowering the drive signal to the IQ mixer, this increases the carrier frequency (as discussed below), resulting in undesirable ghost signals.

[0020] The controller 114 can be housed within or linked to a workstation, such as the computer 112, or another assembly of one or more computing devices in the form of a standalone computing system, a client computer of a server system, a desktop, or a tablet, a display / monitor, and one or more input devices (e.g., a keyboard, joystick, and mouse). The term "controller" broadly encompasses all structural components of an application-specific mainboard or application-specific integrated circuit that control the application of various principles as described in this disclosure, as understood in the art and illustrated by way of example in this disclosure. The structural components of a controller can include, but are not limited to, a processor(s), computer-usable / computer-readable storage medium(s), an operating system, application module(s), peripheral device controller(s), slot(s), and port(s).

[0021] Additionally, while computer 112 illustrates components networked with one another, two such components may be integrated into a single system. For example, computer 112 may be integrated with a display (not shown) and / or system 100. That is, in some embodiments, functionality attributed to computer 112 may be performed (e.g., executed) by system 100. On the other hand, the networked components of computer 112 may be spatially distributed, such as across different rooms or buildings, in which case the networked components may be connected via a data connection. In yet another embodiment, one or more of the components of computer 112 are not connected to other components via a data connection, but instead are manually provided with input or output, such as via a memory stick or other form of memory. In yet another embodiment, functionality described herein may be performed by components of computer 112 but external to system 100.

[0022] Although the various components of system 100 are described in more detail below with respect to exemplary embodiments, a brief description of the functionality of system 100 will now be presented.

[0023] 1A and 1B, during operation, the radar DUT 102 radiates a signal (illustratively a mm-wave signal) that is incident on the array of MRTSs 106. As explained more fully herein, the signal from the radar DUT 102 is selectively reflected between each MRTS 106 and the radar DUT 102 using power levels adapted to emulate distance in both azimuth (±x directions in the coordinate system of FIGS. 1A and 1B) and elevation (±y directions in the coordinate system of FIGS. 1A and 1B). In particular, the respective focal points (or foci) of each of the receive antennas (not shown in FIGS. 1A and 1B) represent targets emulated by the system 100.

[0024] The re-illumination signals from the MRTS 106, which receives the signals from the radar DUT 102, are selectively modified by the MRTS 106 and transmitted back to the radar DUT 102. As explained more fully below, the re-illumination signals from a particular MRTS 106 in the re-illuminator 101 are received at the radar DUT 102 as emulated reflected signals from a target. A computer 112 receives the signals from the radar DUT 102 for further analysis of the accuracy of the radar DUT 102.

[0025] 2 is a simplified circuit diagram of the MRTS 106 of FIGS. 1A and 1B, according to a representative embodiment. Aspects of the MRTS 106 described with respect to the representative embodiment may be common to the MRTS 106 and delay electronics described above, although those aspects may not be repeated. Additionally, various aspects of the MRTS 106 (which may be referred to as MRDs, CMTs, and pixels) are described in commonly assigned U.S. Provisional Application No. 62 / 912,442, filed October 9, 2019. issue, Commonly assigned U.S. patent application Ser. No. 16 / 867,804, filed May 20, 2020 issue, Commonly owned U.S. Provisional Application No. 63 / 046,301, filed June 30, 2020 No. The entire contents of U.S. Provisional Application No. 62 / 912,442, U.S. Patent Application No. 16 / 867,804, and U.S. Provisional Application No. 63 / 046,301 are expressly incorporated herein by reference.

[0026] The MRTS 106 includes an amplifier 202 coupled to a mixer 203, illustratively a variable gain amplifier (VGA). The mixer 203 is an in-phase (I) quadrature (Q) mixer (IQ mixer) or IQ modulator, and for reasons explained below, is advantageously a single-sideband IQ mixer with standard 90-degree phase alignment of the RF signal, thereby outputting either the upper sideband (USB) or the lower sideband (LSB), and rejecting the LSB or USB, respectively. Alternatively, the IQ mixer 203 can be compatible with binary phase modulation (BPM), quaternary phase modulation (QPM), 8-phase modulation, 16-QAM, etc. As discussed below, the modulation is selected to provide a desired approximation of the difference phase symbols. In particular, amplitude approximation may be performed by IQ mixer 203 using techniques within the purview of those skilled in the art.

[0027] In particular, the amplifier 202 of the exemplary embodiment provides two exemplary beneficial functions. IQ mixers are known to suffer from conversion loss, so amplification is required to emulate targets with relatively large radar cross sections (RCS). Moreover, VGAs are useful for selectively varying the RCS. Simply reducing the strength of the I and Q drives is undesirable because this would convey a strong unshifted carrier frequency signal that could result in unwanted ghost targets.

[0028] The output of the IQ mixer 203 is provided to a variable attenuator 204, which selectively modifies the output signal provided by the mixer 203 to provide a desired return signal to the radar DUT 102. Specifically, the signal from the mixer 203 is attenuated by the variable attenuator 204 to advantageously obtain a desired emulated radar cross section (RCS) of the target. As alluded to above, the amplifier 202 and the variable attenuator 204 are connected to the computer 112. Based on instructions in the memory 118, the processor 116 executes the control signals provided by the computer 112 to the variable attenuator 204 to enable emulation of a desired level of a re-illumination signal received at the receive antenna 208 from the radar DUT 102 and returned to the radar DUT 102 from the re-illumination antenna 209.

[0029] In certain exemplary embodiments, the receive antenna 208 and the re-irradiating antenna 209 are horn antennas selected for the wavelength of the signal received from and returned to the radar DUT 102. The receive antenna 208 may have variable gain and may be coupled to a beam-shaping element, such as a lens, to adjust the degrees of freedom of the angle of arrival (AoA) from the radar DUT 102. Horn antennas or similar antennas are not required for the receive antenna 208 and the re-irradiating antenna 209; other types of antennas, such as patch antennas or patch antenna arrays, may be incorporated without departing from the scope of the present teachings.

[0030] In particular, power is used to emulate a consistent radar cross section (RCS). The RCS can be stored, for example, in a look-up table in memory 118. To this end, for a given range r, the return signal is proportional to the RCS, as 1 / r 4Vehicles are commonly said to be 10 dB per square meter (sm), or 10 dBsm, which in plain English is radar speak of a measured area that means 10 square meters. Many objects (people, bicyclists, buildings, etc.) are tabulated, and those that are not can nowadays be calculated by ray tracing techniques. According to the present teachings, the return signal strength (known as 1 / r) corresponding to the distance r of a particular object is 4 Emphasis is placed on providing the radar DUT 102 with an accepted value of SSB strength (obeying radar decay law) and RCS. According to representative embodiments, signal strength (and therefore power) is adjusted by adjusting the strength of the I / Q drive signals from the computer 112 to the MRTS 106 of various embodiments, with weaker I / Q drive signals providing a comparatively weaker emulation signal. In particular, in certain representative embodiments, the computer 112 pre-calculates a consistent return signal to be provided to a single focal point at the radar DUT 102, and the controller 114 then adjusts the strength of the I and Q drives to achieve this SSB strength. Alternatively, the gain of the amplifier 202 or the attenuation by the variable attenuator 204, or both, can be advantageously adjusted by operation of the controller 114 to control the return SSB strength.

[0031] When the vehicle radar is an FMCW device, range / velocity is emulated electronically using the MRTS 106. To this end, the FMCW radar system uses chirp waveforms whereby correlation of the original transmit (Tx) waveform from the radar DUT 102 with the received (Rx) echo waveform reveals the target range. For example, ±k swIn an up-chirp / down-chirp system with a chirp rate (measured in Hz / sec), a target with a relative velocity of 0 at a distance d relative to the ego-vehicle will experience a frequency shift (δf) given by equation (1), where c is the speed of light and the factor 2 is due to the round-trip propagation of the signal from the radar DUT 102. δf = -(±2k SW d / c) Equation (1)

[0032] The sign of this shift depends on which part of the waveform, up-chirp versus down-chirp, is being processed. In contrast, Doppler shift due to relative velocity appears as a "common-mode" frequency shift. For example, a net upshift across both halves of the waveform indicates that the radar DUT is approaching a target. The correlation is performed in the DUT's IF / baseband processor. Bandwidths of several MHz are typical.

[0033] The most commonly deployed variants of FMCW use repeated up-chirps or repeated down-chirps, but not both (with intervening dead time). Thus, the range to the target is determined as in the previous paragraph, but now without the issue of sign. Relative velocity is determined by measuring the phase shift between the IF correlation signals of successive frames, where a frame is the term of art for one period of the waveform. In many FMCW radar applications, the frame repetition rate is typically a few kHz.

[0034] Frequency shifting the chirp signal of an FMCW radar is equivalent to time shifting it, thus implementing the estimated excess range. sw Let be the chirp slope, d0 be the setup distance (including the waveguide distance within the MRTS 106), and d1 be the desired emulation distance, then the required intermediate frequency f IF The (intermediate frequency) shift is given by the following formula: f IF = 2kSW (d1-d2) / c formula (2) where c is the speed of light and the factor 2 is due to round trip propagation.

[0035] 1A, 1B, and 3, when a nearby MRTS 106 is positioned at half the resolution specification of the radar DUT 102 and at the same setup distance d0, the radar DUT 102 will have an equal drive frequency f IF and amplitude, the MRTSs 106 are sensed as a single target at interpolation point 301. Moreover, adjacent MRTSs 1 106 and MRTS2 106 shown in Figure 3 are operated at equal phase, with I1 and I2 in phase with each other and Q1 and Q2 in phase with each other, but their in-phase (I) and quadrature (Q) components being 90 degrees out of phase with each other. Notably, in the exemplary embodiment shown here, the drive frequencies and amplitudes of the excitation for MRTS1 and MRTS2 are both equal, so that interpolation point 301 is located at the bisecting midpoint halfway between MRTS1 and MRTS2.

[0036] The perceived angular position of interpolation point 301 is determined by selecting the amplitude of the signal retransmitted from re-irradiation antenna 209 of MRTS 106. To this end, when phase matching of adjacent MRTSs 1106 and 2106 in FIG. 3 is maintained as described above, the perceived angular position of the target is selected by providing control signals from controller 114 to amplifier 202 and variable attenuator 204 that change the amplitude of the signal retransmitted from re-irradiation antenna 209 of each adjacent MRTS 106 to a selected amplitude, thereby changing the perceived angular position of the target. Thus, when the control signals from controller 114 result in the same amplitude output signals from adjacent MRTSs 106, the emulated target will remain at interpolation point 301 as shown. On the other hand, if the amplitude weightings provided by controller 114 (e.g., the ratio of the output power from MRTS 1106 to the output power from MRTS 2106 in FIG. 3) are unequal, the perceived location of interpolation point 301 will shift closer to MRTS 1106 or farther from MRTS 2106 depending on the relative weightings. Also, the perceived RCS is given by the weighted sum of the individual RCSs of each MRTS 106. RCS coordination works much like the known quasi-optical "grid amplifiers" microwave power combining method.

[0037] 3, the full width, half max (FWHM) resolution of the radar DUT 102 is shown by the ellipse 302. If the MRTS1 106 and MRTS2 106 are finer than this resolution, e.g., δφ=φ res When spaced apart by δφ / 2, MRTS1 106 and MRTS2 106, when active, are sensed as a single target at the interpolated point 301 at the center of the mid-centroid ellipse 302. The angular resolution of a radar device (e.g., radar DUT 102) is typically 16 times coarser than its angular accuracy specification. δφ=φ res / 2 and δθ=θ resBy choosing / 2, an approximately 8-fold reduction in the number of MRTSs 106 is achieved for a linear (1D) array of re-illuminators 101, and an approximately 64-fold reduction in the required MRTSs 106 is achieved for a 2D (xy in the coordinate system of FIG. 1B) array of re-illuminators 101.

[0038] Figure 4A illustrates adjacent, offset MRTSs 106 positioned and controlled to suppress ghost images, according to a representative embodiment. Certain aspects of the adjacent MRTSs 106 described with respect to Figure 4A are common to the arrays of re-illuminators 101 and MRTSs 106 described above with respect to Figures 1A-3 and in the provisional and patent applications attached hereto and incorporated by reference. Details of the common aspects will not necessarily be repeated.

[0039] One type of ghost signal that can occur in a system emulating a radar DUT scene is due to the components used in the emulation setup; these ghost signals are often referred to as "setup ghost signals" due to reflections from the mechanical / physical hardware of the system itself. By way of example only, the array of MRTSs 106 in FIGS. 1A and 1B can be placed as close as one meter from the radar DUT 102 during testing of the radar DUT 102. Placing the array of MRTSs 106 one meter from the radar DUT 102, if unmitigated, could result in ghost signals in front of a vehicle with a radar unit located inside. By way of example only, in certain known emulation systems, the relevant ghost is a carrier-leakage ghost, which causes a certain amount of the original chirp signal to leak through the mixer without a frequency shift. This carrier leakage is retransmitted to the radar with only a small delay compared to the setup ghost. This carrier leakage therefore appears as a ghost at, for example, 1.2 m from the vehicle.

[0040] Additionally, ghost signals known as range ghosts can appear in the MRTS 106 array at approximately integer multiples of the desired simulated target (simulant). For example, mixers have nonlinearities that can also mix harmonics of the IQ drive signal with the millimeter-wave RF signal. When this occurs, according to equation (1), the second harmonic introduces a range ghost at d = 2d - d, the third harmonic introduces a range ghost at d = 3d - 2d, and so on.

[0041] Another type of range ghost occurs due to multipath frequency shifts when pickup-retransmission isolation is insufficient. In this case, the original chirp signal is frequency shifted once during its first pass through the transponder, but then undergoes another frequency shift upon re-entering the pickup antenna. Of course, this loop behavior can occur over and over again, resulting in a series of ghosts appearing at approximately the same distance as the nonlinear harmonic ghost described in the previous paragraph. In fact, the separation distance between the nth pass loop ghost signal and the nth harmonic ghost is approximately the same as the distance between the carrier leakage ghost signal and the setup ghost signal. For simplicity, the MRTS 106 is positioned along the z-axis in the coordinate system of FIG. 4A and staggered in the azimuth (x-axis) direction. Similarly, the MRTS 106 is also staggered along the z-axis (up and down) so that one traverses the MRTS 106 in the up and down (y-axis) direction to enhance ghost suppression. The perceived ghost angle is often straight ahead (x-direction) due to the collective motion of the returning ghost waves from the MRTS 106 .

[0042] According to an exemplary embodiment, the first and third MRTSs 106 (from left to right in FIG. 4A ) are designated odd MRTSs 106 and are located at odd azimuth locations. In contrast, the second and fourth MRTSs 106 (from left to right in FIG. 4A ) are designated even MRTSs 106 and are located at even azimuth locations. The even MRTSs 106 are staggered from the odd MRTSs 106 by λ / 4 in setup distance from the radar DUT, where λ is the wavelength of the radar DUT 102. Thus, the round-trip difference between the even and odd MRTSs 106 is λ / 2, or 180 degrees in electrical phase.

[0043] Without selective phasing of each MRTS, all signals (ghost and simulant) would suffer destructive interference returning to the radar DUT 102. To avoid suppressing the stimulant signal from impinging on the radar DUT 102, the phase of the even (e) MRTS 106 is adjusted so that the phase of the in-phase component is φ(I e ) = 0 degrees (°), and the phase of the quadrature component is φ(Q e )=90 degrees, and the phase of the odd MRTS 106 is set by the controller 114 to be φ(I o )=180 degrees, φ(Q o ) = 270 degrees, where φ represents the phase function. Combined with the physical zigzag arrangement of the MRTSs 106 described above, for an even MRTS 106, the simulant signal is returned with a net phase of 0° + 0° = 0°, and for an odd MRTS 106, the simulant signal is returned with a net phase of 0° + 0° = 0°. 180°+180° ≡ 0° mod 360° where the net phase is the sum of the physical stagger delay and the IF drive. As desired, the two partial simulant signals are in phase and therefore add constructively upon returning to the DUT. Table I is a suppression table showing the net phase of the even and odd MRTSs 106 shown in FIG. 4A and the resulting effect on the simulant and ghost signals. [Table 1]

[0044] In particular, Table 1 applies when any of the interpolation points is located midway between grid points (MRTS 106) as described above with respect to Figure 3. Furthermore, when the amplitude weights of neighboring even and odd MRTSs are essentially equal, the coordinated interference of the return signals will be strictly constructive or strictly destructive.

[0045] Figure 4B illustrates adjacent, offset MRTSs 106 positioned and controlled to suppress ghost images according to an exemplary embodiment. As can be seen, the arrangement of the MRTSs 106 in the exemplary embodiment of Figure 4B is "curved," as opposed to the linear arrangement of the MRTSs 106 in Figure 4A. Certain aspects of the adjacent MRTSs 106 described with reference to Figure 4B are common to the arrays of re-illuminators 101 and MRTSs 106 described above with reference to Figures 1A-4A and in the provisional and patent applications attached hereto and incorporated by reference herein. Details of the common aspects will not necessarily be repeated.

[0046] For ease of explanation, the MRTS 106 is shown in the azimuth direction as shown in FIG.

number

[0047] According to an exemplary embodiment, the first and third MRTSs 106 (from left to right in FIG. 4B ) are designated odd MRTSs 106 and are located at odd azimuth locations. In contrast, the second and fourth MRTSs 106 (from left to right in FIG. 4B ) are designated even MRTSs 106 and are located at even azimuth locations. Similar to the exemplary embodiment described with respect to FIG. 4A , the even MRTSs 106 are staggered from the odd MRTSs 106 by λ / 4 in setup distance from the radar DUT, where λ is the wavelength of the radar DUT 102. Thus, the round-trip difference between the even and odd MRTSs 106 is λ / 2, or 180 degrees in electrical phase.

[0048] Without selective phasing of each MRTS to further mitigate and suppress ghost signals, all signals (ghost and simulant) would suffer destructive interference back to the radar DUT 102. To avoid suppressing the stimulant signal from impinging on the radar DUT 102, the phase of the even (e) MRTS 106 is adjusted so that the phase of the in-phase component is φ(I e ) = 0 degrees, and the phase of the quadrature component is φ(Q e )=90 degrees, and the phase of the odd MRTS 106 is set by the controller 114 to be φ(I o )=180 degrees, φ(Q o ) = 270 degrees, where φ represents the phase function. Combined with the physical zigzag arrangement of the MRTSs 106 described above, for an even MRTS 106, the simulant signal is returned with a net phase of 0° + 0° = 0°, and for an odd MRTS 106, the simulant signal is returned with a net phase of 0° + 0° = 0°. 180°+180° ≡ 0° mod 360° where the net phase is the sum of the physical stagger delay and the IF drive. As desired, the two partial simulant signals are in phase and therefore add constructively on their return to the DUT.

[0049] Another case is described with respect to FIG. 5, which illustrates the emulation of a target consisting of a single, isolated MRTS 106 (pixel), according to a representative embodiment. Again, certain aspects of the representative embodiment described here are common to the re-illuminators 101 and arrays of MRTSs 106 described above with respect to FIGS. 1A-4 and in the provisional and patent applications attached hereto and incorporated by reference. Details of the common aspects are not necessarily repeated. In particular, in FIG. 5, the length of the arrows represents the signal tone power.

[0050] In FIG. 5, the target consists of a single pixel (a single MRTS). This is often the case for distant targets, so a weaker return signal is emulated. At the target MRTS pixel, the IQ drive is moderate, so there is no need for a strong drive signal from the controller 114 provided to the MRTS because the emulated target is at a relatively large distance. MRTSs in the vicinity of one MRTS have their IQ drive signals further reduced or even turned off. In analog mixers, more carrier leakage occurs when the IQ drive signals are relatively weak. Therefore, the attenuation provided by the respective variable attenuators (see FIG. 2) at the neighboring MRTSs is increased so that the total carrier leakage power of the neighboring MRTSs matches that of the target MRTS. Because the neighboring IQ drive signals are already small, their SSB tones are small, and the high attenuation reduces them below the noise level. Therefore, the SSB tones of neighboring MRTSs are invisible to the radar DUT 102.

[0051] In the embodiment described here, even and odd cancellation of nonlinear second harmonics and two-pass loop ghosts is not achieved because the 2f IFThe power is negligible due to the very weak IQ drive and high attenuation, however this is tolerable as the MRTS pixel itself receives only modest IQ drive signals from the controller and a relatively well-designed mixer together with reasonable pickup-retransmit isolation avoids range ghosting at and near d2.

[0052] Table II below is a table of suppression when the target is on an isolated MRTS pixel. [Table 2]

[0053] Finally, intermediate cases, such as interpolation points that are neither halfway between pixel grid points, nor exactly on the grid, whose pixel locations (e.g., x, y coordinates (not shown in FIG. 5)) are simply handled in an intermediate manner between the ghost suppression methods of FIG. 4 and FIG. 5, where the grid is a 2D array of MRTSs. For example, the drive signals from controller 114 to the IQ mixers (see FIG. 2) and the attenuation levels set by controller 114 for successive neighboring variable attenuators (see FIG. 2) are adjusted to achieve the desired interpolation position and weights representing the sensed RCS as described above with respect to FIG. 3, but also to maximize carrier leakage suppression. Referring to FIG. 3 (but now with the λ / 4 physical stagger and even IF to odd IF phase matching discussed in Table I above), there are four real variables that can be controlled, namely, I1-Q1 drive strength, I2-Q2 drive strength, MTRS1 attenuation level, and MRTS2 attenuation level, but apart from the desired ones (two simulant weights and leakage balance), so quite generally, a set of solutions always exists.

[0054] In view of the above, the present disclosure is therefore intended to achieve one or more of the advantages, as specifically mentioned below, through one or more of its various aspects, embodiments, and / or specific features or subcomponents. For purposes of explanation and not limitation, exemplary embodiments disclosing specific details are described to provide a thorough understanding of an embodiment in accordance with the present teachings. However, other embodiments that depart from the specific details disclosed herein but are not inconsistent with the present disclosure may still be within the scope of the appended claims. Furthermore, descriptions of known devices and methods may be omitted so as not to obscure the description of the exemplary embodiments. Such methods and devices are within the scope of the present disclosure.

[0055] While various target emulation for automotive radar systems have been described with reference to several exemplary embodiments, it should be understood that the words used are words of description and illustration, rather than words of limitation. Changes may be made within the purview of the appended claims, as referenced and amended, without departing from the scope and spirit of dynamic echo signal emulation for automotive radar sensor configurations in their aspects. While dynamic echo signal emulation for automotive radar sensor configurations has been described with reference to particular means, materials, and embodiments, the dynamic echo signal emulation for automotive radar sensor configurations is not intended to be limited to the details disclosed. Rather, the dynamic echo signal emulation for automotive radar sensor configurations extends to all functionally equivalent structures, methods, and uses as fall within the scope of the appended claims.

[0056] The illustrations of the embodiments described herein are intended to provide a comprehensive understanding of the structure of various embodiments. The illustrations are not intended to serve as a complete description of all elements and features of the disclosure described herein. Numerous other embodiments may become apparent to those skilled in the art upon reviewing the present disclosure. Other embodiments may be utilized and derived from the present disclosure, such that structural and logical substitutions and changes may be made without departing from the scope of the disclosure. Moreover, the illustrations are merely representational and may not be drawn to scale. Certain proportions within the illustrations may be exaggerated, while other proportions may be minimized. Therefore, the disclosure and figures should be considered illustrative, not limiting.

[0057] One or more embodiments of the present disclosure may be individually and / or collectively referred to herein by the term "the present teachings," but this is for convenience only and is not intended to voluntarily limit the scope of the present application to any particular invention or inventive concept. Furthermore, while specific embodiments have been illustrated and described herein, it should be understood that any later device designed to serve the same or similar purpose may be substituted for the specific embodiment shown. The present disclosure is intended to cover any and all later modifications and variations of the various embodiments. Combinations of the above embodiments, as well as other embodiments not specifically described herein, will be apparent to those skilled in the art upon reviewing the description.

[0058] The Abstract of the Disclosure is provided to comply with 37 CFR 1.72(b) and is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Moreover, in the foregoing Detailed Description, various features may be grouped together or described in a single embodiment for the purpose of streamlining the disclosure. This disclosure should not be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the appended claims reflect, inventive subject matter may be directed to less than all features of any of the disclosed embodiments. Accordingly, the appended claims are hereby incorporated into the Detailed Description, with each claim standing on its own as defining separately claimed subject matter.

[0059] The preceding description of the disclosed embodiments has been provided to enable any person skilled in the art to easily understand the concepts described in the present disclosure. In that case, the above disclosed subject matter may be The appended claims are intended to be illustrative and not limiting, and are intended to cover the full scope of the present invention. All such modifications, improvements and other embodiments that fall within the true spirit and scope of the disclosure are hereby incorporated by reference. Accordingly, to the fullest extent permitted by law, the scope of this disclosure The scope of the present invention is determined by the broadest permissible interpretation of the appended claims and their equivalents. and should not be limited or restricted by the preceding detailed description. The claims as originally filed are as follows: Claim 1: a redirection element adapted to receive electromagnetic waves; the re-illumination element is adapted to transmit a response signal, the re-illumination element comprising a plurality of small radar target simulators (MRTS (106)), each comprising a receive antenna, a variable gain amplifier (202) (VGA), an in-phase quadrature (IQ) mixer (203), a variable attenuator (204), and a transmit antenna; The MRTSs (106) are arranged in an array including rows and columns of the MRTSs (106), with each MRTS (106) in the array being spaced a lateral distance p from an adjacent MRTS (106). x and spaced apart vertically by a distance p y spaced apart, direction angle The incremental angle of the angle (δφ) and and the increment of the angle between the upper and lower angles (δθ) However, the azimuth resolution specification (φ res ) and vertical resolution specifications (θ res ) a system (100) for testing vehicle radar that is more sensitive than a conventional radar. Claim 2: 10. The system of claim 1, wherein the re-illumination element is configured to emulate an apparent target distance or an apparent target velocity, or both. Claim 3: Each MRTS (106) in the array is spaced a lateral distance p from an adjacent MRTS (106). x and spaced apart vertically by a distance p y separated by ,direction angle The incremental angle of the angle (δφ) and and the increment of the angle between the upper and lower angles (δθ) However, the azimuth resolution specification (φ res ) and vertical resolution specifications (θ res 10. The system of claim 1, wherein the ion beam is finer than the ion beam. Claim 4: before Writing style angle The incremental angle of the angle (δφ) is approximately half of the azimuth resolution specification (φ res 4. The system (100) of claim 3, wherein: Claim 5: before As mentioned above bottom corner The incremental angle of the angle(δθ) is approximately half of the vertical resolution specification (θ res 4. The system (100) of claim 3, wherein: Claim 6: before Writing style angle The incremental angle of the angle (δφ) is approximately half of the azimuth resolution specification (φ res / 2), and As mentioned above bottom corner The incremental angle of the angle (δθ) is approximately half of the vertical resolution specification (θ res 4. The system (100) of claim 3, wherein: Claim 7: a redirection element adapted to receive electromagnetic waves; the re-illumination element is adapted to transmit a response signal, the re-illumination element comprising a plurality of small radar target simulators (MRTS (106)), each comprising a receive antenna, a variable gain amplifier (202) (VGA), an in-phase quadrature (IQ) mixer (203), a variable attenuator (204), and a transmit antenna; A system (100) for testing a vehicle radar, wherein the MRTS (106) is arranged in an array including rows and columns of the MRTS (106), the VGA and the variable attenuator (204) are configured to control an emulated radar cross section (RCS) of a target, and the array comprises a plurality of MRTSs (106) arranged in a staggered manner displaced from a device under test (DUT). Claim 8: 8. The system (100) of claim 7, wherein the rows of the MRTSs (106) are staggered in the azimuth direction and the columns of the MRTSs (106) are staggered in the vertical direction. Claim 9: 9. The system of claim 8, wherein the rows of the MRTSs are even MRTSs and odd MRTSs, the even MRTSs and the odd MRTSs being displaced from each other by a distance from the DUT equal to λ / 4, where λ is the wavelength of the DUT, the even MRTSs each comprise an even number of in-phase / quadrature (IQ) mixers, the odd MRTSs each comprise an odd number of IQ mixers, the even MRTSs are driven by IF phases of 0 degrees and 90 degrees, and the odd MRTSs are driven by IF phases of 180 degrees and 270 degrees. Claim 10: 9. The system of claim 8, wherein the rows of the MRTSs are even MRTSs and odd MRTSs, the even MRTSs and the odd MRTSs being displaced from each other by a distance from the DUT equal to λ / 4, where λ is the wavelength of the DUT, the even MRTSs each comprise an even number of in-phase / quadrature (IQ) mixers, the odd MRTSs each comprise an odd number of IQ mixers, the even MRTSs are driven by IF phases of 0 degrees and 90 degrees, and the odd MRTSs are driven by IF phases of 180 degrees and 270 degrees. Claim 11: A system (100) for testing a vehicle radar, comprising: a redirection element adapted to receive electromagnetic waves, the redirection element adapted to transmit a response signal, the redirection element comprising a plurality of small radar target simulators (MRTSs (106)), each comprising a receive antenna, a variable gain amplifier (202) (VGA), an in-phase quadrature (IQ) mixer (203), a variable attenuator (204), and a transmit antenna, the MRTSs (106) being arranged in an array including rows and columns of the MRTSs (106), each MRTS (106) being spaced a lateral distance p from an adjacent MRTS (106); x and spaced apart vertically by a distance p y separated by ,direction angle The incremental angle of the angle (δφ) and and the increment of the angle between the upper and lower angles (δθ) However, the azimuth resolution specification (φ res ) and vertical resolution specifications (θ res ) a re-irradiation element that is finer than the a controller (114) comprising a memory (118) for storing instructions and a processor (116) for executing the instructions, the controller (114) being configured to control the re-illumination element and to perform a performance test on the vehicle radar including a plurality of targets; A system comprising: Claim 12: 12. The system (100) of claim 11, wherein the redirection element is adapted to emulate an apparent target distance or an apparent target velocity, or both. Claim 13: before Writing style angle The incremental angle of the angle (δφ) is approximately half of the azimuth resolution specification (φ res 12. The system (100) of claim 11, wherein: Claim 14: before As mentioned above bottom corner The incremental angle of the angle (δθ) is approximately half of the vertical resolution specification (θ res 12. The system (100) of claim 11, wherein: Claim 15: before Writing style angle The incremental angle of the angle (δφ) is approximately half of the azimuth resolution specification (φ res / 2), and As mentioned above bottom corner The incremental angle of the angle (δθ) is approximately half of the vertical resolution specification (θ res 12. The system (100) of claim 11, wherein:

Claims

1. a redirection element adapted to receive electromagnetic waves; The re-illumination element is adapted to transmit a response signal, the re-illumination element comprising a plurality of small radar target simulators (MRTS (106)), each comprising a receive antenna, a variable gain amplifier (202) (VGA), an in-phase quadrature (IQ) mixer (203), a variable attenuator (204), and a transmit antenna; The MRTSs (106) are arranged in an array including rows and columns of the MRTSs (106), with each MRTS (106) in the array being a lateral distance p from an adjacent MRTS (106). ｘ and spaced apart by a distance p ｙ spaced apart, The incremental angle of the azimuth angle (δφ) and the incremental angle of the elevation angle (δθ) are determined based on the azimuth resolution specification (φ ｒｅｓ ) and vertical resolution specifications (θ ｒｅｓ ) is more subtle than A system (100) for testing a vehicle radar, wherein the array comprises a plurality of MRTSs (106) arranged in a staggered arrangement displaced from a device under test (DUT).

2. A system (100) as described in claim 1, wherein the rows of the plurality of MRTSs (106) are arranged in a zigzag pattern in the azimuth direction, and the columns of the plurality of MRTSs (106) are arranged in a zigzag pattern in the vertical direction.

3. The system (100) of claim 1, wherein the redirection element is configured to emulate an apparent target distance or an apparent target velocity, or both.

4. The increment angle of the azimuth angle (δφ) is approximately half the azimuth resolution specification (φ ｒｅｓ 2. The system (100) of claim 1, wherein:

5. The increment angle (δθ) of the vertical angle is approximately half of the vertical resolution specification (θ ｒｅｓ 2. The system (100) of claim 1, wherein:

6. The increment angle of the azimuth angle (δφ) is approximately half the azimuth resolution specification (φ ｒｅｓ / 2), and the increment angle (δθ) of the angle forming the vertical angle is approximately half of the vertical resolution specification (θ ｒｅｓ 2. The system (100) of claim 1, wherein:

7. a redirection element adapted to receive electromagnetic waves; The re-illumination element is adapted to transmit a response signal, the re-illumination element comprising a plurality of small radar target simulators (MRTS (106)), each comprising a receive antenna, a variable gain amplifier (202) (VGA), an in-phase quadrature (IQ) mixer (203), a variable attenuator (204), and a transmit antenna; The MRTSs (106) are arranged in an array including rows and columns of the MRTSs (106), the VGA and the variable attenuator (204) are configured to control an emulated radar cross section (RCS) of a target, and the array comprises a plurality of MRTSs (106) displaced from a device under test (DUT) and arranged in a staggered manner.

8. The system (100) of claim 7, wherein rows of the plurality of MRTSs (106) are staggered in an azimuth direction and columns of the plurality of MRTSs (106) are staggered in an up-down direction.

9. 9. The system of claim 8, wherein the rows of the plurality of MRTSs are even MRTSs and odd MRTSs, the even MRTSs and the odd MRTSs being displaced from each other by a distance from the DUT equal to λ / 4, where λ is the wavelength of the DUT, the even MRTSs each comprising an even number of in-phase and quadrature (IQ) mixers, the odd MRTSs each comprising an odd number of IQ mixers, the even MRTSs being driven by IF phases of 0 degrees and 90 degrees, and the odd MRTSs being driven by IF phases of 180 degrees and 270 degrees.

10. 9. The system of claim 8, wherein the row of the plurality of MRTSs comprises an even MRTS and an odd MRTS, the even MRTS and the odd MRTS being displaced from each other by a distance from the DUT equal to λ / 4, where λ is the wavelength of the DUT, the even MRTSs each comprising an even number of in-phase and quadrature (IQ) mixers, the odd MRTSs each comprising an odd number of IQ mixers, the even MRTSs being driven by IF phases of 0 degrees and 90 degrees, and the odd MRTSs being driven by IF phases of 180 degrees and 270 degrees.

11. A system (100) for testing a vehicle radar, comprising: a redirection element adapted to receive electromagnetic waves, the redirection element adapted to transmit a response signal, the redirection element comprising a plurality of small radar target simulators (MRTSs (106)), each having a receive antenna, a variable gain amplifier (202) (VGA), an in-phase quadrature (IQ) mixer (203), a variable attenuator (204), and a transmit antenna, the plurality of MRTSs (106) being arranged in an array including rows and columns of the plurality of MRTSs (106), each MRTS (106) being spaced a lateral distance p from an adjacent MRTS (106); ｘ and spaced apart by a distance p ｙ and the increments of the azimuth angle (δφ) and elevation angle (δθ) are within the azimuth resolution specification (φ ｒｅｓ ) and vertical resolution specifications (θ ｒｅｓ ) a re-irradiation element that is finer than the a controller (114) comprising a memory (118) for storing instructions and a processor (116) for executing the instructions, the controller (114) being configured to control the re-illumination element and to perform a performance test on the vehicle radar including a plurality of targets; Equipped with The array comprises a plurality of MRTSs arranged in a staggered arrangement displaced from a device under test (DUT).

12. The system (100) of claim 11, wherein the redirection element is adapted to emulate an apparent target distance or an apparent target velocity, or both.

13. The increment angle of the azimuth angle (δφ) is approximately half the azimuth resolution specification (φ ｒｅｓ 12. The system (100) of claim 11, wherein:

14. The increment angle (δθ) of the vertical angle is approximately half of the vertical resolution specification (θ ｒｅｓ 12. The system (100) of claim 11, wherein:

15. The increment angle of the azimuth angle (δφ) is approximately half the azimuth resolution specification (φ ｒｅｓ / 2), and the increment angle (δθ) of the angle forming the vertical angle is approximately half of the vertical resolution specification (θ ｒｅｓ 12. The system (100) of claim 11, wherein:

16. The system of claim 11 , wherein rows of the plurality of MRTSs are staggered in an azimuth direction and columns of the plurality of MRTSs are staggered in an up-down direction.

17. 17. The system of claim 16, wherein the rows of the plurality of MRTSs are even MRTSs and odd MRTSs, the even MRTSs and the odd MRTSs are displaced from each other by a distance from the DUT equal to λ / 4, where λ is the wavelength of the DUT, the even MRTSs each comprise an even number of in-phase and quadrature (IQ) mixers, the odd MRTSs each comprise an odd number of IQ mixers, the even MRTSs are driven by IF phases of 0 degrees and 90 degrees, and the odd MRTSs are driven by IF phases of 180 degrees and 270 degrees.

18. 17. The system of claim 16, wherein the row of MRTSs is an even MRTS and an odd MRTS, the even MRTS and the odd MRTS being displaced from each other by a distance from the DUT equal to λ / 4, where λ is the wavelength of the DUT, the even MRTSs each comprising an even number of in-phase and quadrature (IQ) mixers, the odd MRTSs each comprising an odd number of IQ mixers, the even MRTSs being driven by IF phases of 0 degrees and 90 degrees, and the odd MRTSs being driven by IF phases of 180 degrees and 270 degrees.

Images