Radar target simulator front end and simulation method

Abstract

The invention relates to a radar target simulator front end and a simulation method. A radar target simulator front end is provided, which is configured to simulate at least one radar target for testing a radar device under test. The radar target simulator front end comprises at least two antenna elements arranged along a first angle under study. The at least two antenna elements are configured to be selectively activated and deactivated. When each of the at least two antenna elements is activated, the antenna element thereby generates a simulated radar target along the first angle under study.

Description

TECHNICAL FIELD

[0001] The present invention relates to testing radar devices, in particular testing road vehicle radar devices, and to a corresponding method for simulating a radar target. BACKGROUND

[0002] Road vehicle radar devices are used to detect objects surrounding the vehicle. In order to test such radar devices, it is necessary to verify the ability of the device to detect objects under controlled conditions.

[0003] Conventional test setups employ actual target objects which are placed in the vicinity of the radar device under test and actively moved with respect to the radar device under test to simulate the movement of real-world objects.

[0004] For example, document EP 3 143 712 B1 shows such a conventional radar test system. Such a setup is able to produce accurate results, but is too large and cumbersome to be used in a production test environment only. SUMMARY

[0005] Therefore, there is a need to provide a radar target simulator front end and a simulation method which allows testing of radar devices under test with a minimum of hardware effort and minimal space requirements.

[0006] According to a first aspect of the present invention, a radar target simulator front end is provided which is configured to simulate at least one radar target for testing a radar device under test. The radar target simulator front end comprises at least two antenna units arranged along a first angle under investigation. The at least two antenna units are configured to be selectively activated and deactivated. Thereby, when each of the at least two antenna units is activated, it generates a simulated radar target along the first angle under investigation. This allows simulating radar targets at two different positions with respect to the radar device under test without the need of any physical movement within the system.

[0007] Advantageously and preferably, each of the at least two antenna units comprises a transmitting antenna and a receiving antenna. This allows a good signal separation and thereby improves the quality of the radar signals received by the radar device under test.

[0008] Preferably, the transmitting antenna and the receiving antenna of each of the at least two antenna units are arranged with respect to each other along an angle orthogonal to the first angle under investigation. This allows reducing the size of the antenna units along the first angle under investigation, in turn allowing closely spaced placement of multiple antenna units along the first angle under investigation, thereby improving the angular resolution which can be tested.

[0009] Advantageously and preferably, the transmitting antenna and the receiving antenna of each antenna unit are arranged at an angular distance with respect to each other, which angular distance is smaller than the angular resolution of the radar device under test. This results in that the radar device under test is not able to distinguish the positions of the transmitting antenna and the receiving antenna, giving the radar device under test the impression of actually measuring radar reflections of real world radar objects.

[0010] Alternatively and preferably, each antenna unit of the at least two antenna units comprises a combined transmitting / receiving antenna. This reduces the overall size of the antenna units and at the same time ensures that the radar signals received by the radar device under test are very close to the scattered signals of real world radar objects.

[0011] Advantageously and preferably, the at least two antenna units are configured to be activated jointly, thereby simulating at least two simulated radar targets. This allows for more complex tests.

[0012] Preferably, the radar target simulator front end is configured to simulate a near field radar target by jointly activating at least two adjacent antenna units of the at least two antenna units. This allows for an increased radar target simulation flexibility.

[0013] Advantageously and preferably, the radar target simulator front end comprises a plurality of antenna units arranged along a first angle under study. The plurality of antenna units is configured to be selectively activated and deactivated, each antenna unit of the plurality of antenna units generating a simulated radar target when the antenna unit is activated. This allows for a very high angular resolution and for a smooth movement of the simulated radar target along the first angle under study.

[0014] Preferably, the radar target simulator front end further comprises at least two additional antenna units arranged along a second angle under study. The at least two additional antenna units are configured to be selectively activated and deactivated, each antenna unit of the at least two additional antenna units generating a simulated radar target along the second angle under study when the antenna unit is activated. This allows for measurements along the second angle under study.

[0015] Preferably, the first angle under study and the second angle under study are orthogonal to each other. This allows for measuring radar targets, for example, along the azimuth angle and along the elevation angle.

[0016] Preferably, the radar target simulator front end is configured to simulate radar targets for testing multiple input multiple output (MIMO) radar devices under test and / or multiple input single output (MISO) radar devices under test. This allows for a very flexible use of the radar target simulator front end of the present invention.

[0017] Advantageously and preferably, the radar target simulator front end further comprises a plurality of antenna elements arranged in a two-dimensional angular pattern. The plurality of antenna elements is configured to be selectively activated and deactivated, each of the plurality of antenna elements producing a simulated radar target at a specific two-dimensional angular position. This allows to place simulated radar targets like pixels in a two-dimensional grid, resulting in a very high measurement flexibility.

[0018] Preferably, the radar target simulator front end further comprises an antenna element switch configured to selectively activate and deactivate at least two antenna elements. This makes it possible to have a higher degree of automation.

[0019] Preferably, the antenna element switch is configured to successively activate and deactivate adjacent antenna elements of the at least two antenna elements, thereby simulating a movement of the simulated radar target. This allows for a very simple measurement setup.

[0020] According to a second aspect of the present application, a method for simulating at least one radar target for testing a radar device under test is provided. The method comprises providing at least two antenna elements arranged along a first angle to be investigated, selectively activating and deactivating antenna elements of the at least two antenna elements, and thereby producing a simulated radar target along the first angle to be investigated when activated.

[0021] Preferably, a number of antenna element pairs is constructed at an angle to simulate a number of possible angles to be investigated.

[0022] Preferably, the antenna element pairs are aligned in a specific direction to test radar targets along angles in this specific direction.

[0023] Preferably, the antenna element pairs are designed within an angular resolution unit.

[0024] Preferably, a two-dimensional alignment of antenna elements is performed by constructing pixels.

[0025] Preferably, near field targets are simulated. BRIEF DESCRIPTION OF DRAWINGS

[0026] Example embodiments of the present application will now be further explained, by way of example only, with reference to the accompanying drawings in which:

[0027] Figure 1 A first exemplary embodiment of a radar target simulator front end of the present application is shown;

[0028] Figure 2 A detail view of a second exemplary embodiment of a radar target simulator front end of the present application is shown;

[0029] Figure 3a detail view of a third exemplary embodiment of a radar target simulator front-end of the present invention is shown;

[0030] Figure 4 a fourth exemplary embodiment of a radar target simulator front-end of the present invention is shown; and

[0031] Figure 5 an exemplary embodiment of a method of the present invention is shown in a flow chart. DETAILED DESCRIPTION

[0032] First, reference is made to Figure 1 the general idea and function of the present invention is explained. More details of the present invention are explained by different embodiments of the apparatus. Finally, with regard to Figures 2 to 4 detailed functions of embodiments of the method of the present invention are described. Similar entities and reference signs in different figures are partly omitted. Figure 5

[0033] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The following embodiments of the present invention can, however, be varied and are not limited to the following embodiments but include modifications and equivalents of the following embodiments.

[0034] First embodiment

[0035] Figure 1 In the first embodiment of a radar target simulator front-end 1 of the present invention and a radar under test (DUT) 2 are shown. The radar under test 2 is a multiple-input multiple-output (MIMO) radar under test or a multiple-input single-output (MISO) radar under test. Even a single-input single-output (SISO) radar under test can be tested with this setup.

[0036] Here, the radar target simulator front-end 1 comprises a plurality of antenna units (AU) 10, 11, 12, 13, 14 and 15, which are arranged along a first angle x of interest with respect to the radar under test 2. Here, the antenna units 12-15 are shown with dashed lines, indicating that these antenna units constitute optional components. Each of the antenna units 10-15 is configured to be selectively activated and deactivated. In the activated state, each antenna unit 10-15 generates a radar reflection, while in the deactivated state, none of the antenna units 10-15 generates a radar reflection.

[0037] During the test, the radar under test 2 sends a radar signal to the radar target simulator front-end 1. All activated antenna units 10-15 generate an artificial scattering signal and send it back to the radar under test 2. In Figure 1 ​In a first example, only antenna element 10 is active, so only antenna element 10 generates and returns an analog scattered signal to the radar device under test 2. Thus, antenna element 10 simulates a real-world radar target at its position.

[0038] With respect to the internal working of the antenna elements 10-15, reference is made to Figure 2 and Figure 3 , Figure 2 and Figure 3 will be explained in the following for the second and third embodiment, but are similar to the working here.

[0039] To simulate a movement of a real-world radar target along the first angle x under study, at least two of the antenna elements 10-15 can be activated and deactivated jointly. This simulates a larger radar target or simulates near-field conditions.

[0040] To simulate a movement of a real-world radar target along the first angle x under study, at least two of the antenna elements 10-15 can be activated and deactivated jointly. This simulates a larger radar target or simulates near-field conditions.

[0041] Preferably, the antenna elements 10-15 are configured to simulate a radar target for radar frequencies 50-130 GHz, preferably 70-90 GHz, most preferably 76-81 GHz, when activated.

[0042] Although only six antenna elements 10-15 are shown here, far more than this number of antenna elements can be employed. For example, the number of antenna elements arranged along the first angle x under study can be 50 to 150 antenna elements, preferably 96 antenna elements.

[0043] It is also possible to employ only two antenna elements. This still allows for a digital movement between two angular positions.

[0044] Second embodiment

[0045] Figure 2 In Fig. 2, a detail view of a second embodiment of the radar target simulator front-end of the present application is shown. Here, only a single antenna element 10 is shown. Here, the antenna element 10 comprises a transmitting antenna (Tx) 20 and a receiving antenna (Rx) 21. The receiving antenna 21 is configured to receive a radar signal transmitted by the radar device under test 2, while the transmitting antenna 20 is configured to transmit an analog scattered signal back to the radar device under test 2.

[0046] In the simplest configuration, the activation of the antenna unit 10 is achieved by connecting the transmitting antenna 20 to the receiving antenna 21, while the deactivation is achieved by disconnecting the connection between the transmitting antenna 20 and the receiving antenna 21.

[0047] In a more complex setup, the radar target simulator front end 1 is connected to a target simulator back end (not shown here). The back end is then configured to process the radar signals received by the receiving antenna 21 and to generate therefrom simulated scattering signals which are then passed to the transmitting antenna 20 to be transmitted to the radar device under test 2.

[0048] In particular, the target simulator back end can then comprise a down-converter configured to down-convert the radar signals received by the receiving antenna 21 to the baseband range.

[0049] The target simulator back end can further comprise a baseband processor configured to add fading, and / or damping, and / or attenuation, and / or multipath propagation, and / or noise.

[0050] The target simulator back end can further comprise an up-converter configured to generate the simulated scattering signals by up-converting the down-converted radar signals received by the receiving antenna 21, or by up-converting the processed signals provided by the baseband processor.

[0051] In particular, a separate target simulator, e.g. an R&S AREG, can be used as the target simulator back end.

[0052] Further, Figure 2 A first angle x under investigation and a second angle y orthogonal to the first angle x under investigation are shown in the middle. Preferably, the transmitting antenna 20 and the receiving antenna 21 are arranged relative to each other along the second angle y orthogonal to the first angle x under investigation. This allows to construct the antenna unit 10 with very small dimensions along the first angle x under investigation, allowing to place very many antenna units along the first angle under investigation, in turn allowing for a high angular resolution.

[0053] The transmitting antenna 20 and the receiving antenna 21 are placed at a position where their centers have an angular distance d relative to each other. This angular distance is smaller than the angular resolution of the radar device under test. This prevents phase errors in case of a MIMO radar device under test.

[0054] Preferably, the angular distance d between the centers of the transmitting antenna and the receiving antenna is 1 mm to 10 mm, more preferably 2 mm to 5 mm, most preferably 3 mm.

[0055] When the distance between the radar target simulator front end 1 and the radar device under test 2 is 1-2 m, an angular resolution of 0.02-1°, more preferably 0.05-0.5°, most preferably 0.1°, can preferably be achieved.

[0056] Third embodiment

[0057] Figure 3 Fig. 3 shows another detail of an embodiment of the radar target simulator front end of the present application. Here, the internal working of a single antenna unit 10 is shown. Here, the antenna unit 10 comprises a combined transmit / receive antenna (Tx / Rx) 30. The transmit / receive antenna 30 is used both for receiving radar signals transmitted by the radar device under test 2 and for transmitting simulated scattered signals to the radar device under test 2.

[0058] In the simplest configuration, deactivation of the transmit / receive antenna 30 can be achieved by disconnecting the different parts of the antenna by means of a switch, thus significantly changing the frequency response of the antenna, thereby significantly reducing the size of the reflected radar signal. Activation in this case is achieved by connecting the parts again.

[0059] In a more complex setup, as described with reference to Figure 2 the radar signals received by the transmit / receive antenna 30 are passed to the radar target simulator back end and processed thereby, and the signals for transmission are passed back to the transmit / receive antenna 30. The difference to the setup described with reference to Figure 2 is only that the signals are received and transmitted successively by the same transmit / receive antenna 30, instead of being received by a dedicated receive antenna and then transmitted by a dedicated transmit antenna.

[0060] In practice, multiple antenna units are grouped into antenna modules, also referred to as QAT modules. Each antenna module comprises at least 4 antenna units. In the case of the embodiment described with reference to Figure 2 the antenna module comprises 4 transmit antennas and 4 receive antennas. In the case of the embodiment described with reference to Figure 3 the antenna module comprises 4 joint antennas.

[0061] Each antenna unit can be built as a single integrated circuit on a single microchip.

[0062] The antenna units can then be activated individually or jointly.

[0063] The antenna module can further comprise signal distribution hardware configured to distribute signals received by the individual antennas to the radar simulator back end and to distribute signals provided by the radar simulator back end to the individual antennas.

[0064] In addition, the antenna module can also comprise a state machine for controlling the individual antennas.

[0065] The antenna module can also comprise an interface configured to connect and / or synchronize at least two antenna modules. In particular, a cascade and / or a daisy chain of antenna modules can be realized by the interface.

[0066] The radar simulator backend comprises, for example, 4 microwave sources and / or up to 8 signal conditioning units for the transmission path, and / or 10 signal conditioning units for the reception path, configured to perform the aforementioned processing.

[0067] The radar simulator backend can also comprise a communication unit configured to communicate with the radar target simulator frontend 1.

[0068] Fourth embodiment

[0069] Figure 4 In this figure, a further embodiment of the radar target simulator frontend 1 of the present application is shown. Here, in addition to the antenna units 10-15 arranged along a first angle x to be investigated, there are additional antenna units 40, 41, 42 and 43 arranged along a second angle y to be investigated. Preferably, the first angle x to be investigated and the second angle y to be investigated are orthogonal to each other.

[0070] In addition to the simulation of radar targets arranged along the first angle x to be investigated, Figure 4 The arrangement in this figure also allows the simulation of radar targets arranged along the second angle y to be investigated by selectively activating and deactivating the antenna units 40, 41, 42 and 43. Advantageously, when simulating radar targets arranged along the second angle y to be investigated, the antenna unit 13 arranged between the antenna unit 41 and the antenna unit 42 can also be used as part of the additional antenna units 40, 41, 42 and 43.

[0071] In this embodiment, an antenna unit switch 45 is also shown. The antenna unit switch 45 is connected to each individual antenna unit. For the sake of clarity, the individual connections are omitted in this figure. The antenna unit switch 45 performs the activation and deactivation of the individual antenna units in order to simulate the radar targets.

[0072] In addition to the two-dimensional arrangement of the antenna units 10-15, 40-43 shown here, a two-dimensional grid of antenna units forming a pixel can also be employed. In this case, a simultaneous movement of the simulated radar targets along the first angle to be investigated and the second angle to be investigated is possible.

[0073] Although in the above embodiments the radar target simulator frontend 1 is shown as a separate unit, it is also possible to integrate the radar target simulator frontend 1 into the radar simulator backend. Figure 4Only 4 special antenna elements 40, 41, 42 and 43 arranged along a second angle y to be investigated are shown in Fig. 4, but a much larger number of antenna elements can be employed. In particular, 50-150 antenna elements, preferably 96 antenna elements, can also be employed here.

[0074] Instead of arranging the antenna elements 40, 41 and 42, 43 spaced apart from the antenna elements 10-15, the antenna elements 40, 41, 42 and 43 can also be placed adjacent to the antenna elements 10-15, thus resulting in a modular design, in which modules of connected antenna elements can be placed as desired. One module can for example be formed by Figure 1

[0075] Fifth embodiment

[0076] Figure 5 In Fig. 5, a flow chart of an exemplary embodiment of the method of the present application is shown. In a first step 100, at least two antenna elements arranged along a first angle to be investigated are provided. In a second step 101, the antenna elements of the at least two antenna elements are selectively activated and deactivated. In a third step 102, a simulated radar target along the first angle to be investigated is generated by the antenna elements activated in the second step 101.

[0077] Embodiments of the present application can be implemented by hardware, software, or any combination thereof. The various embodiments of the present application can be implemented by one or more application specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), one or more field programmable gate arrays (FPGAs), one or more processors, one or more controllers, one or more micro-controllers, one or more microprocessors, etc.

[0078] The various embodiments of the present application can also be implemented in the form of software modules, routine, functions, etc. performing the above-described features or operations. The software code can be stored in a memory unit so that it can be executed by a processor. The memory unit can be located inside or outside the processor and can communicate data with the processor through various known means.

[0079] The present application is not limited to the above examples, in particular not to the specific number of antenna elements or the frequency of the radar signals. The present application discussed above can be applied to a variety of types of radar systems to be investigated. The features of the exemplary embodiments can be used in any advantageous combination.

[0080] ​While the application and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the application as defined by the appended claims.

Claims

1. A radar target simulator front end configured to simulate at least one radar target for testing a radar device under test, the radar target simulator front end comprising at least two antenna units arranged along a first angle under study, wherein the at least two antenna units being configured to be selectively activated and deactivated, each of the at least two antenna units, when activated, producing a simulated radar target along the first angle under study, wherein the radar target simulator front end is further configured to simulate a near- field radar target by jointly activating at least two adjacent antenna units of the at least two antenna units.

2. The radar target simulator front end of claim 1, wherein each of the at least two antenna units comprising a transmit antenna and a receive antenna.

3. The radar target simulator front end of claim 2, wherein the transmit antenna and the receive antenna of each of the at least two antenna units being arranged relative to each other along an angle orthogonal to the first angle under study.

4. The radar target simulator front end of claim 2, wherein the transmit antenna and the receive antenna of each antenna unit being arranged relative to each other at an angular distance, the angular distance being smaller than an angular resolution of the radar device under test.

5. The radar target simulator front end of claim 1, wherein, each of the at least two antenna units comprising a combined transmit / receive antenna.

6. The radar target simulator front end of claim 1, wherein the at least two antenna units being configured to be jointly activated, thereby simultaneously producing at least two simulated radar targets.

7. The radar target simulator front end of claim 1, the radar target simulator front end comprising a plurality of antenna units arranged along the first angle under study, wherein the plurality of antenna units being configured to be selectively activated and deactivated, each of the plurality of antenna units, when activated, producing a simulated radar target.

8. The radar target simulator front end of claim 1, the radar target simulator front end comprising at least two additional antenna units arranged along a second angle under study, wherein the at least two additional antenna units being configured to be selectively activated and deactivated, each of the at least two additional antenna units, when activated, producing a simulated radar target along the second angle under study.

9. The radar target simulator front end of claim 7, wherein, the first angle under study and the second angle under study being orthogonal to each other.

10. The radar target simulator front end of claim 1, wherein the radar target simulator front end being configured to simulate radar targets for testing a multiple-input-multiple-output radar device under test or a multiple-input-single-output radar device under test.

11. The radar target simulator front end of claim 1, the radar target simulator front end comprising a plurality of antenna units, wherein, the plurality of antenna units being arranged in a two-dimensional angular pattern, wherein the plurality of antenna elements is configured to be selectively activated and deactivated, each of the plurality of antenna elements producing a simulated radar target at a specific two-dimensional angular position.

12. The radar target simulator front-end of claim 1, the radar target simulator front-end comprises an antenna element switch configured to selectively activate and deactivate the at least two antenna elements.

13. The radar target simulator front-end of claim 12, wherein, the antenna element switch is configured to successively activate and deactivate directly adjacent antenna elements of the at least two antenna elements, thereby simulating movement of the simulated radar target.

14. A method for simulating at least one radar target for testing a radar under test, the method comprising: - providing at least two antenna elements arranged along a first angle to be investigated; - selectively activating and deactivating antenna elements of the at least two antenna elements; and - producing a simulated radar target along the first angle to be investigated when activated, wherein a near-field radar target is simulated by jointly activating at least two adjacent antenna elements of the at least two antenna elements.

15. The method of claim 14, wherein constructing many antenna element pairs at an angle to simulate many possible angles to be investigated.

16. The method of claim 15, wherein the antenna element pairs are aligned in a specific direction to test radar targets at angles along the specific direction.

17. The method of claim 15, wherein the antenna element pairs are designed to be within an angular resolution unit.

18. The method of claim 14, wherein the two-dimensional alignment of the antenna elements is performed by constructing pixels.

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