Coordinated mini-radar target simulators 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 GHz to 300 GHz frequency spectrum. Millimeter wave (mm wave) automotive radar is an important technology for existing advanced driver-assistance systems (ADAS) and planned autonomous driving systems. For example, millimeter wave automotive radar is used in ADAS to warn of forward and rear collisions. Furthermore, millimeter 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 can operate both day and night. The cost of adapting millimeter wave automotive radar has fallen to a level where it can be deployed on a large scale at present. As a result, millimeter-wave automotive radar is now widely used in advanced driver-assistance systems for long-range, medium-range, and short-range environmental sensing. Furthermore, millimeter-wave automotive radar is likely to be widely used in autonomous driving systems currently under development.

[0002] The actual driving environments in which automotive radar may be deployed can vary considerably, and many such environments can be complex. For example, real-world driving environments may contain numerous objects, some of which have complex reflective and diffracting properties that affect the echo signal. As a direct result of misdetecting and / or interpreting the echo signal, false warnings or inappropriate responses may be triggered, or warnings or responses that should be triggered may not be triggered, which could lead to accidents.

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

[0004] Single-target radar emulators are known. However, emulating real-world driving scenarios requires emulating multiple targets. For example, a radar-equipped vehicle might 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, due to the expensive electronics, not scalable to larger numbers. Moreover, most known emulators only emulate an incomplete subset of range, speed, and AoA.

[0005] Therefore, what is needed is a system that emulates multiple targets encountered by a radar system, overcoming at least the shortcomings of the known radar emulators mentioned above.

[0006] The exemplary embodiments are best understood from the following detailed description when read in conjunction with the attached drawings. It should be emphasized that various features are not necessarily depicted to scale. In practice, dimensions may be arbitrarily enlarged or reduced to clarify the considerations. Where applicable and practical, the same reference number refers to the same element. [Brief explanation of the drawing]

[0007] [Figure 1A] This is a simplified block diagram showing a system for testing vehicle radar according to a typical embodiment. [Figure 1B] This is a simplified block diagram of an array for a miniature radar target simulator (MRTS) according to a typical embodiment. [Figure 2] This is a simplified circuit diagram of an MRTS according to a typical embodiment. [Figure 3] This is a simplified block diagram of adjacent MRTS used to interpolate emulated targets placed between them, according to a typical embodiment. [Figure 4A] This figure shows adjacent offset MRTS, useful for suppressing ghost images, according to a typical embodiment. [Figure 4B] This figure shows a typical embodiment of adjacent offset MRTS arranged in a curved configuration, which is useful for suppressing ghost images. [Figure 5] This figure shows a typical embodiment of target emulation consisting of a single MRTS. [Modes for carrying out the invention]

[0008] The following detailed description includes, for illustrative purposes only and without limitation, representative embodiments that disclose specific details in order to fully understand one embodiment of this teaching. Descriptions of known systems, devices, materials, methods of operation, and methods of manufacture may be omitted to avoid obscuring the description of the representative embodiments. Nevertheless, systems, devices, materials, and methods that are within the understanding of those skilled in the art may be used in accordance with the representative embodiments within the scope of this teaching. It should be understood that the terms used herein are intended solely to describe specific embodiments and are not intended to limit them. Defined terms have meanings that are generally understood and accepted in the art of this teaching, in addition to their scientific and technical meanings.

[0009] In this specification, terms such as "first," "second," and "third" may be used to describe various elements or components, but it should be understood that these elements or components should not be limited by these terms. These terms are used solely to distinguish one element or component from another. Accordingly, the first element or component discussed below may be referred to as the second element or component without departing from the teachings of this disclosure.

[0010] The terms used in this specification are for the sole purpose of describing particular embodiments 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. Further, the terms "comprises," "comprising," and / or similar terms when used in this specification specify the presence of the stated features, elements, and / or components but do not preclude the presence or addition of one or more other features, elements, components, and / or groups thereof. As used in this specification, 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 should be 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 terms and similar terms include instances where one or more intermediate elements or components may be utilized to connect two elements or components. However, when an element or component is said to be "directly connected" to another element or component, this includes only instances where the two elements or components are connected to each other without using any intermediate or intervening elements or components.

[0012] 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 an electromagnetic wave and transmit a response signal. The re-illumination element includes a plurality of miniature radar target simulators (MRTSs), each MRTS 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 the rows and columns of the MRTSs, and each MRTS of the array is laterally spaced from an adjacent MRTS by a distance p x and longitudinally spaced from an adjacent MRTS by a distance p y . The incremental subtended azimuth angle (δφ) and the incremental subtended elevation (δθ) angle are finer than the azimuth resolution specification (φ res ) and the elevation resolution specification (θ res ) of the radar device under test (DUT).

[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 an electromagnetic wave and transmit a response signal. The re-illumination element includes a plurality of miniature radar target simulators (MRTSs), each MRTS 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 the rows and columns of the MRTSs. The VGA and the variable attenuator are configured to control the radar cross section (RCS) of the emulated target, and the plurality of MRTSs of the array are displaced from the device under test (DUT) and arranged in a zigzag pattern.

[0014] A system for testing vehicle radar is disclosed, as described herein in relation to various representative embodiments. The system comprises a re-irradiation element adapted to receive electromagnetic waves and transmit response signals. The re-irradiation element comprises a plurality of miniature radar target simulators (MRTS), each MRTS comprising a receiving antenna, a variable gain amplifier (VGA), an in-phase orthogonal (IQ) mixer, a variable attenuator, and a transmitting antenna. The MRTS are arranged in an array comprising rows and columns of the MRTS, and each MRTS in the array is configured to test the resolution specification (θ) of the radar device under test (DUT). res ) from a horizontal distance p x They are separated, with a vertical distance p y It is separated from the others. The system also includes a controller which has a memory for storing instructions and a processor for executing those instructions. This controller is configured to control the re-illumination elements and operate adjacent MRTS. The incremental subtended azimuth angle (δφ) and incremental subtended vertical (δθ) angles are the azimuth resolution specifications (φ) on a vehicle radar including multiple targets. res ) and is more precise than the height test.

[0015] Among its many advantages, the emulation provided by the system described herein is particularly based on the "coordinated modulation" of the MRTS as described herein. For this purpose, as will be more fully described herein, the modulation of the MRTS arranged in the array to provide a re-irradiator is coordinated to provide angular interpolation and suppression of numerous ghost signals.

[0016] Figures 1A and 1B are simplified block diagrams showing a system 100 for testing vehicle radar according to an exemplary embodiment. As will be appreciated by those skilled in the art having the benefit of this disclosure, one promising vehicle radar is automotive radar that is used in various accommodation capabilities in current and emerging automotive applications. However, it should be emphasized that the system 100 for testing vehicle radar described herein is not limited to automotive radar systems, but can also be applied to other types of vehicles including buses, motorcycles, motorized bicycles (e.g., scooters), and other vehicles that can use vehicle radar systems.

[0017] According to an exemplary embodiment, the system 100 is prepared to test a radar device under test (DUT) 102. The system 100 includes a re-irradiator 101 comprising an array of MRTSs 106. The array of MRTSs 106 in FIG. 1A is two-dimensional and extends in the xy direction according to the coordinate system of FIG. 1A. Thus, FIG. 1B shows the two-dimensional array of MRTSs 106 from a vantage point of the radar DUT 102 (i.e., in the xy plane of FIG. 1B). As will be described more fully below, the MRTSs 106 of the system 100 are adapted to emulate targets in one or two dimensions. Moreover, the array of MRTSs 106 of the re-irradiator 101 can be relatively flat (e.g., in the xy plane as shown in FIG. 1B), can be curved in an arc along a single row array, or can be curved in two dimensions of a multi-row and multi-column array.

[0018] The array of MRTSs 106 has a lateral spacing p as shown in FIGS. 1A and 1B x and a vertical spacing p y For reasons that will be explained in more detail below, the lateral spacing p between adjacent MRTSs 106 x is selected such that the incremental sub-tended azimuth (δφ in FIG. 1A) is slightly finer than the azimuth resolution specification (φ res ), and the vertical spacing p between adjacent MRTSs 106y The incremental subtended vertical (δθ, not shown) angle has a vertical resolution (θ). res It is selected to be slightly finer than ). According to a typical embodiment which will be discussed in more detail below, δφ = φ res / 2 and δθ=θ res It is / 2.

[0019] As described below with respect to Figure 2, each MRTS 106 comprises a transmitting antenna (not shown in Figures 1A and 1B) and a receiving antenna (not shown in Figures 1A and 1B). There is one MRTS 106 for each target to be emulated, as will be more fully described herein. The system also comprises a computer 112. The computer 112 comprises, exemplarily, a controller 114 as described herein. The controller 114 as described herein may include a combination of a processor 116 and a memory 118 for storing instructions. The processor 116 executes instructions to carry out the processes described herein. For this purpose, the computer 112 is adapted to control the re-irradiator 101, in addition to controlling the functions of the radar DUT 102, according to a typical embodiment. As will be explained more thoroughly below, instructions stored in memory 118 are executed by processor 116 to modify the signal strength (and therefore power) of the selected MRST 106 by adjusting the drive signal from computer 112 to MRTS 106, so that, according to this teaching, a weaker drive signal provides a relatively weaker response emulation signal, and a stronger drive signal provides a relatively stronger response emulation signal. However, in particular, in certain embodiments, the relatively large amplitude and emulation strength (and the RCS thereby emulated) of the drive signal to the IQ mixer of MRTS 106 are adjusted by VGA. This technique is preferable for reducing the amplitude of the desired stimulus signal by reducing the drive signal to the IQ mixer, but this increases the carrier frequency (as described below), resulting in an undesirable ghost signal.

[0020] The controller 114 may also be housed in or linked to a separate assembly consisting of a workstation such as a computer 112, or a client computer of a standalone computing system, a server system, one or more computing devices in the form of a desktop or 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 herein, as understood in the art of this disclosure and illustrated by example herein. The structural components of a controller may include, but are not limited to, processors, computer-enabled / computer-readable storage media, operating systems, application modules, peripheral device controllers, slots, and ports.

[0021] In addition, although computer 112 represents networked components, two such components can be integrated into a single system. For example, computer 112 can be integrated with a display (not shown) and / or system 100. That is, in some embodiments, functions belonging to computer 112 can be performed (e.g., executed) by system 100. On the other hand, the networked components of computer 112 can also be spatially distributed by distributing them in different rooms or different buildings, in which case the networked components can be connected via data connections. In yet another embodiment, one or more components of computer 112 are not connected to other components via data connections, but instead are manually input or output by a memory stick or other form of memory. In yet another embodiment, the functions described herein are elements of computer 112, but can be performed based on the functions of elements outside of system 100.

[0022] Various components of System 100 will be described in more detail below with respect to representative embodiments, but a brief explanation of the functions of System 100 will be presented here.

[0023] Referring to Figures 1A and 1B, during operation, the radar DUT 102 emits a signal (an example of a mm-wave signal) that is incident on the array of MRTS 106. As will be more fully described 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 systems of Figures 1A and 1B) and up / down (±y directions in the coordinate systems of Figures 1A and 1B). In particular, each focal point (or foci) of each receiving antenna (not shown in Figures 1A and 1B) represents a target to be emulated by the system 100.

[0024] The re-irradiation signal from MRTS106, which receives signals from radar DUT102, is selectively modified by MRTS106 and sent back to radar DUT102. As will be explained more thoroughly below, the specific re-irradiation signal from MRTS106 of the re-irradiator 101 is received in radar DUT102 as an emulated reflected signal from the target. Computer 112 receives signals from radar DUT102 for further analysis of the accuracy of radar DUT102.

[0025] Figure 2 is a simplified circuit diagram of the MRTS106 shown in Figures 1A and 1B, according to a typical embodiment. The embodiments of the MRTS106 described in relation to a typical embodiment may be common to the MRTS106 and delay electronic devices described above, but these embodiments may not be repeated. Furthermore, various embodiments of the MRTS106 (sometimes referred to as MRD, CMT, and pixel) may be similar to those described in U.S. Provisional Application No. 62 / 912,442 (attached), filed October 9, 2019, U.S. Patent Application No. 16 / 867,804 (attached), filed May 20, 2020, and U.S. Provisional Application No. 63 / 046,301 (attached), filed June 30, 2020, by the same applicant. 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 MRTS106 includes an amplifier 202 connected to a mixer 203. This amplifier is, exemplarily, a variable gain amplifier (VGA). Mixer 203 is an in-phase quadrature (IQ) mixer or IQ modulator, and for reasons described below, is advantageously a single-sideband IQ mixer with standard 90-degree phase matching of RF signals, resulting in outputting either an upper sideband (USB) or a lower sideband (LSB), blocking either the LSB or USB, respectively. Alternatively, IQ mixer 203 can be adapted to binary phase modulation (BPM), quaternary phase modulation (QPM), 8-phase modulation, 16QAM, etc. The modulation is selected to provide a desired degree of approximation of the difference phase symbols, as discussed below. In particular, amplitude approximation can be performed by the IQ mixer 203 using techniques within the understanding of those skilled in the art.

[0027] In particular, the amplifier 202 of a typical embodiment provides two exemplary beneficial functions. IQ mixers are known to suffer conversion losses, and therefore amplification is required to emulate targets with relatively large radar cross-sections (RCS). Furthermore, VGA is useful for selectively changing the RCS. Simply reducing the intensity of the I and Q drives is undesirable because it transmits a strong, unshifted carrier frequency signal that can result in unwanted ghost targets.

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

[0029] In a particular representative embodiment, the receiving antenna 208 and the re-irradiation antenna 209 are horn antennas selected for the wavelength of the signal received from and returned to the radar DUT 102. The receiving antenna 208 may have variable gain and be coupled to a beam-shaping element such as a lens to adjust the degree of freedom of the angle of arrival (AoA) from the radar DUT 102. Horn antennas or similar antennas are not essential to the receiving antenna 208 and the re-irradiation antenna 209, and other types of antennas such as patch antennas or patch antenna arrays may be incorporated without departing from the scope of this teaching.

[0030] In particular, power is used to emulate a consistent radar cross-section (RCS). The RCS can be stored, for example, in a lookup table in memory 118. For this purpose, for a given range r, the return signal is proportional to the RCS and 1 / r 4It is known that this decreases as follows. Vehicles are typically said to have a radar speak of 10 dB per square meter (sm), or 10 dBsm, which in plain English means 10 square meters. Many objects (people, cyclists, buildings, etc.) are listed in tables, and those not listed can now be calculated using ray tracing techniques. According to this instruction, the return signal intensity corresponding to the distance r of a specific object (known 1 / r) is... 4 The focus is on providing the radar DUT 102 with the radar decay law and the accepted value of the RCS. In a typical embodiment, the 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 in various embodiments, with weaker I / Q drive signals providing a comparatively weaker emulation signal. In particular, in a certain typical embodiment, the computer 112 pre-calculates a consistent return signal provided to a single focus in the radar DUT 102, and the controller 114 then adjusts the strength of the I and Q drives to achieve this SSB strength. Alternatively, advantageously, the gain of the amplifier 202 or the attenuation by the variable attenuator 204, or both, can be adjusted by the operation of the controller 114 controlling the return SSB strength.

[0031] When the vehicle radar is an FMCW device, distance / speed is electronically emulated using MRTS106. For this purpose, the FMCW radar system uses a chirp waveform, thereby correlating the original transmitted (Tx) waveform from the radar DUT102 with the received (Rx) echo waveform to reveal the target distance. For example, ±k swIn an up-chirp / down-chirp system with a chirp rate (measured in Hz / sec), a relative velocity target of 0 at a distance d from the vehicle results in a frequency shift (δf) given by equation (1), where c is the speed of light and the coefficient 2 is due to the round-trip propagation of the signal from the radar DUT102. δf = -(±2k SW d / c) Equation (1)

[0032] The sign of this shift depends on which portion of the waveform—up-chirp or down-chirp—is being processed. In contrast, Doppler shifts due to relative velocity appear 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. Correlation is performed in the DUT's IF / baseband processor, with bandwidths of several MHz being common.

[0033] The most commonly deployed variant of FMCW uses either repeated up-chirps or repeated down-chirps, but neither is used (with an intervening dead time). Thus, the distance to the target is determined as in the previous paragraph, without regard to positive or negative signs. The relative velocity is determined by measuring the phase shift between consecutive frames of IF-correlated signals, where a frame is a term of art for one period of a waveform. In many FMCW radar applications, the frame repetition rate is typically several kHz.

[0034] Shifting the chirp signal of an FMCW radar is equivalent to shifting it in time, and therefore implements the estimated excess range. sw If we define the chirp slope as d0, the setup distance (including the waveguide distance within the MRTS106), and the desired emulation distance as d1, 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) Here, c is the speed of light, and the coefficient 2 is due to round-trip propagation.

[0035] Referring to Figures 1A, 1B, and 3, if the neighboring 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 When operating at the same amplitude, these MRTS106 are sensed as a single target at the interpolation point 301. Furthermore, the adjacent MRTS1106 and MRTS2106 shown in Figure 3 operate in equal phase, with I1 and I2 being in phase with each other, and Q1 and Q2 being in phase with each other, but their respective in-phase (I) and orthogonal (Q) components being 90 degrees out of phase with each other. In particular, in the exemplary embodiment shown herein, the excitation drive frequencies and amplitudes of MRTS1 and MRTS2 are both equal, and therefore the interpolation point 301 is located at a bisecting midpoint midway between MRTS1 and MRTS2.

[0036] The perceived angular position of interpolation point 301 is determined by selecting the amplitude of the signal retransmitted from the re-irradiation antenna 209 of MRTS106. To this end, assuming that the phase matching of adjacent MRTS1106 and MRTS2106 in Figure 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 perceived angular position of the target by changing the amplitude of the signal retransmitted from each re-irradiation antenna 209 of adjacent MRTS106 to a selected amplitude. Therefore, if the amplitude output signals from adjacent MRTS106 are the same as a result of the control signals from controller 114, the emulated target remains 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 MRTS1106 to the output power from MRTS2106 in Figure 3) are not equal, the sensed position of interpolation point 301 shifts closer to MRTS1106 and further away from MRTS2106, depending on the relative weightings. Also, the sensed RCS is given by the weighted sum of the individual RCSs of each MRTS106. RCS coordination functions quite similarly to the microwave power coupling method of known quasi-optical "grid amplifiers".

[0037] Referring particularly to Figure 3, the full width at half maximum (FWHM) resolution of radar DUT102 is shown by ellipse 302. MRTS1106 and MRTS2106 have a finer resolution than this, for example, δφ = φ res When separated by 2, MRTS1106 and MRTS2106, when active, are perceived as a single target at the interpolation point 301 at the center of the ellipse 302, which is the intermediate centroid. The angular resolution of a radar device (e.g., radar DUT102) is typically 16 times coarser than its angular accuracy specification. δφ=φ res / 2 and δθ=θ resBy selecting / 2, the number of MRTS106 re-irradiators 101 for linear (1D) arrays is reduced by approximately 8 times, and the number of MRTS106 re-irradiators 101 for 2D (xy coordinate system in Figure 1B) arrays is reduced by approximately 64 times.

[0038] Figure 4A shows adjacent offset MRTS 106 arranged and controlled to suppress ghost images according to a typical embodiment. Certain aspects of the adjacent MRTS 106 described in relation to Figure 4A are common to the arrays of re-irradiators 101 and MRTS 106 described above with respect to Figures 1A to 3 and in the provisional and patent applications that form part of this specification and are attached herein. Details of the common aspects are not necessarily repeated.

[0039] One type of ghost signal that may occur in a system emulating a radar DUT scene is due to the components used in the emulation setup, and these ghost signals are often called "setup ghost signals" due to reflections from the system's own mechanical / physical hardware. As a mere example, the MRTS106 array in Figures 1A and 1B can be placed as close as 1 meter from the radar DUT102 during testing of the radar DUT102. Placing the MRTS106 array 1 meter from the radar DUT102 could result in ghost signals in front of a vehicle containing a radar unit, if not mitigated. As a mere example, in certain known emulation systems, the relevant ghost is carrier-leakage ghost, which causes a certain amount of the original chirp signal to leak through the mixer without frequency shift. This carrier leakage is retransmitted to the radar with only a slight delay compared to setup ghost. Therefore, this carrier leakage appears, for example, as a ghost signal at 1.2m from the vehicle.

[0040] Furthermore, ghost signals known as range ghosts may appear in the MRTS106 array at approximately integer multiples of the desired simulated target (simulant). For example, the mixer has a nonlinearity that allows harmonics of the IQ drive signal to also be mixed with the millimeter-wave RF signal. When this occurs, according to equation (1), the second harmonic introduces a range ghost at d2 = 2d1 - d0, the third harmonic introduces a range ghost at d3 = 3d1 - 2d0, and so on for subsequent higher harmonics.

[0041] Another type of range ghosting occurs due to multipath frequency shifts when pickup-retransmission separation is insufficient. In this case, the original chirp signal is frequency-shifted once as it first passes through the transponder, but then re-enters the pickup antenna and is frequency-shifted again. Of course, this loop behavior can occur repeatedly, resulting in a series of ghosts appearing at approximately the same distance as the nonlinear harmonic ghosts in the previous paragraph. In fact, the separation distance between the ghost signal in the nth pass-through loop 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 of explanation, the MRTS106 are positioned along the z-axis in the coordinate system of Figure 4A and zigzag in the azimuthal (x-axis) direction. Similarly, to enhance ghost suppression, the MRTS106 are also zigzag along the z-axis (up and down) such that one traverses the MRTS106 in the vertical (y-axis) direction. The detected ghost angle is often linear (straight ahead) (in the x-direction) due to the collective action of return ghost waves from MRTS106.

[0042] In a typical embodiment, the first and third MRTS106 (from left to right in Figure 4A) are designated as odd-numbered MRTS106 and are positioned in odd-numbered azimuthal locations. In contrast, the second and fourth MRTS106 (from left to right in Figure 4A) are designated as even-numbered MRTS106 and are positioned in even-numbered azimuthal locations. The even-numbered MRTS106 are positioned in a zigzag pattern from the odd-numbered MRTS106 by λ / 4 in the setup distance from the radar DUT, where λ is the wavelength of the radar DUT102. Therefore, the round-trip difference between the even-numbered MRTS106 and the odd-numbered MRTS is λ / 2, i.e., 180 degrees in electrical phase.

[0043] Without selective phase matching of each MRTS, all signals (ghosts and simulants) will be subjected to destructive interference returning to the radar DUT102. To avoid suppressing the incidence of stimulant signals into the radar DUT102, the phase of the even (e) MRTS106 is such that the phase of the common component is φ(I e ) = 0 degrees (°), and the phase of the orthogonal component is φ(Q e The controller 114 sets the phase to φ(I) = 90 degrees, and the phase of the odd-numbered MRTS 106 is φ(I) o )=180 degrees, φ(Q o The setting is such that ) = 270 degrees. Here, φ represents the phase function. When combined with the physical zigzag arrangement of the MRTS106 described above, in even-numbered MRTS106s, the simulated signal is returned with a net phase of 0° + 0° = 0°, and in odd-numbered MRTS106s, the simulated signal is, 180° + 180° ≡ 0° mod 360° It is returned with the following: Here, the net phase is the sum of the physical zigzag placement delay and the IF drive. As desired, the two partial simulant signals are in phase and therefore reinforce each other and add up when returned to the DUT. Table I is a suppression table showing the net phase of the even and odd MRTS106 shown in Figure 4A and the resulting effect on the simulant and ghost signals. [Table 1]

[0044] In particular, Table 1 applies when any of the interpolator points are located midway between the grid points (MRTS106) as described above with respect to Figure 3. Furthermore, when the amplitude weights of neighboring even and odd MRTS are essentially equal, the coordinated interference of the return signals either strictly reinforces or strictly cancels each other out.

[0045] Figure 4B shows adjacent offset MRTS106 arranged and controlled to suppress ghost images according to a typical embodiment. As can be seen, the arrangement of MRTS106 in the typical embodiment of Figure 4B is "curved" in contrast to the linear arrangement of MRTS106 in Figure 4A. Certain aspects of adjacent MRTS106 described with respect to Figure 4B are common to the arrays of re-irradiators 101 and MRTS106 described above with respect to Figures 1A to 4A and in the provisional and patent applications that form part of this specification and are attached herein. Details of the common aspects are not necessarily repeated.

[0046] To simplify the explanation, the MRTS106 is azimuth as shown in Figure 4B.

number

[0047] In a typical embodiment, the first and third MRTS106 (from left to right in Figure 4B) are designated as odd-numbered MRTS106 and are positioned in odd-numbered azimuthal locations. In contrast, the second and fourth MRTS106 (from left to right in Figure 4B) are designated as even-numbered MRTS106 and are positioned in even-numbered azimuthal locations. Similar to the typical embodiment described with respect to Figure 4A, the even-numbered MRTS106 are positioned in a zigzag pattern from the odd-numbered MRTS106 by λ / 4 in the setup distance from the radar DUT, where λ is the wavelength of the radar DUT102. Therefore, the round-trip difference between the even-numbered MRTS106 and the odd-numbered MRTS is λ / 2, i.e., 180 degrees in electrical phase.

[0048] If ghost signals are not further reduced and suppressed for the selective phase matching of each MRTS, all signals (ghost and simulant) will suffer destructive interference returning to the radar DUT102. To avoid suppressing the incidence of stimulant signals to the radar DUT102, the phase of even (e) MRTS106 is such that the phase of the common component is φ(I e ) = 0 degrees, and the phase of the orthogonal component is φ(Q e The controller 114 sets the phase to φ(I) = 90 degrees, and the phase of the odd-numbered MRTS 106 is φ(I) o )=180 degrees, φ(Q o The setting is such that ) = 270 degrees. Here, φ represents the phase function. When combined with the physical zigzag arrangement of the MRTS106 described above, in even-numbered MRTS106s, the simulated signal is returned with a net phase of 0° + 0° = 0°, and in odd-numbered MRTS106s, the simulated signal is, 180° + 180° ≡ 0° mod 360° It is returned with the following: Here, the net phase is the sum of the physical zigzag placement delay and the IF drive. As desired, the two partial simulant signals are in phase and therefore reinforce each other and add up when returning to the DUT.

[0049] Another case is described with respect to Figure 5. Figure 5 shows an emulation of a target consisting of a single isolated MRTS 106 (pixel) according to a typical embodiment. Again, certain aspects of the typical embodiment described herein are common to the arrays of re-irradiators 101 and MRTS 106 described above with respect to Figures 1A to 4, and to the provisional and patent applications that form part of this specification and are attached herein. Details of the common aspects are not necessarily repeated. In particular, in Figure 5, the length of the arrow represents the signal tone power.

[0050] In Figure 5, the target consists of a single pixel (a single MRTS). This is often the case for distant targets, and therefore a weaker return signal is emulated. At the target MRTS pixel, the IQ drive is moderate, and therefore, since the emulated target is at a relatively large distance, a strong drive signal from controller 114 supplied to the MRTS is not necessary. MRTS in the vicinity of one MRTS have an IQ drive signal that is further reduced or, in some cases, stopped. In the analog mixer, more carrier leakage occurs when the IQ drive signal is relatively weak. Therefore, the attenuation provided by each variable attenuator (see Figure 2) at the neighboring MRTS is increased so that the total carrier leakage power of the neighboring MRTS matches the carrier leakage power of the target MRTS. Since the neighboring IQ drive signals are already small, their SSB tones are small, and the high attenuation brings them down below the noise level. Therefore, the SSB tones of adjacent MRTS are not visible to radar DUT 102.

[0051] In the embodiments described herein, even and odd cancellation of nonlinear second harmonics and two-pass loop ghosts is not achieved. This is because the 2f emitted by the nearby MRTS IFPower consumption can be ignored due to very weak IQ drive and high attenuation. However, this is acceptable because the MRTS pixels themselves receive only moderate IQ drive signals from the controller, and a relatively well-designed mixer, along with reasonable pickup-retransmission separation, avoids range ghosting in and around d2.

[0052] Table II below shows the suppression when the target lies on a separated MRTS pixel. [Table 2]

[0053] Finally, intermediate cases such as interpolation points that are neither midway between pixel grid points, which are pixel locations (e.g., x, y coordinates (not shown in Figure 5)), nor exactly on the grid, are simply handled in an intermediate form between the ghost suppression method of Figure 4 and the ghost suppression method of Figure 5, where the grid is a 2D array of MRTS. For example, the drive signal from controller 114 to the IQ mixer (see Figure 2) and the attenuation levels set by controller 114 for the successive neighborhood variable attenuators (see Figure 2) are adjusted to achieve the desired interpolation position and weights representing the sensed RCS as described above with respect to Figure 3, but also to maximize carrier leakage suppression. Referring to Figure 3 (where the physical zigzag arrangement of λ / 4 and the phase matching of even IFs versus odd IFs discussed in Table I above), there are four controllable real variables, namely the I1-Q1 drive strength, the I2-Q2 drive strength, the damping level of MTRS1, and the damping level of MRTS2, with the desirable ones being the two simulant weights and the leakage balance, and therefore, fairly generally, a set of solutions always exists.

[0054] In consideration of the foregoing, this disclosure is therefore intended to reveal one or more advantages, such as those specifically mentioned below, through one or more of its various aspects, embodiments, and / or specific features or sub-components. For illustrative purposes only, and not limiting, exemplary embodiments disclosing specific details are described in order to fully understand one embodiment of the teaching. However, other embodiments that deviate from the specific details disclosed herein but are not inconsistent with this disclosure are still within the scope of the appended claims. Furthermore, descriptions of known apparatus and methods may be omitted so as not to obscure the description of exemplary embodiments. Such methods and apparatus are within the scope of this disclosure.

[0055] While various target emulations relating to automotive radar systems have been described with reference to several representative embodiments, it should be understood that the language used is descriptive and illustrative, not restrictive. Modifications can be made within the scope and intent of the dynamic echo signal emulation relating to automotive radar sensor configurations in those embodiments, as mentioned herein and as modified. While the dynamic echo signal emulation relating to automotive radar sensor configurations has been described with reference to specific means, materials, and embodiments, it is not intended to be limited to the disclosed details. Rather, the dynamic echo signal emulation relating to automotive radar sensor configurations extends to all functionally equivalent structures, methods, and applications, as found within the scope of the appended claims.

[0056] The examples of embodiments described herein are intended to provide a comprehensive understanding of the structure of various embodiments. These examples 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 who have reviewed this disclosure. Other embodiments may be utilized and derived from this disclosure to enable structural and logical substitutions and modifications without departing from the scope of this disclosure. Furthermore, the examples are merely illustrative and may not be drawn to scale. Certain proportions in the examples may be exaggerated, while others may be minimized. Therefore, the disclosure and figures should be considered illustrative, not limiting.

[0057] One or more embodiments of this disclosure may be referred to individually and / or collectively in this specification by the term “Teaching,” but this is for convenience only and is not intended to arbitrarily limit the scope of this 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 used instead of the specific embodiments illustrated. This disclosure is intended to cover all possible later modifications and variations of the various embodiments. Combinations of the embodiments described above, and other embodiments not specifically described herein, will be apparent to those skilled in the art who have reviewed the description.

[0058] This abstract of the disclosure is provided in accordance with U.S. Patent Law Enforcement Rules 1.72(b) and is filed with the understanding that it will not be used to interpret or limit the claims or their meaning. Furthermore, in the modes for carrying out the prior invention, various features may be grouped together or described in a single embodiment for the purpose of simplifying the disclosure. The disclosure should not be construed as reflecting an intention that the claimed embodiments require more features than are explicitly enumerated in each claim. Rather, as the appended claims reflect, the subject matter of the invention may cover fewer features than all the features of any embodiment of the disclosed embodiments combined. Thus, the appended claims are incorporated into the modes for carrying out the invention, and each claim stands alone as defining separately claimed subject matter.

[0059] The prior description of the disclosed embodiments is provided to enable any person skilled in the art to practice the concepts described herein. In this context, the disclosed subject matter is to be considered illustrative and not limiting, and the appended claims are intended to cover all such modifications, improvements and other embodiments that fall within the true spirit and scope of this disclosure. Accordingly, to the maximum extent permitted by law, the scope of this disclosure should be determined by the broadest and most acceptable interpretation of the appended claims and their equivalents, and should not be limited or restricted by the prior detailed description.

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.

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