EP4264314A1

EP4264314A1 - Programmable fiber-optic delay line

Info

Publication number: EP4264314A1
Application number: EP21839115.9A
Authority: EP
Inventors: Jonathan Watkins
Original assignee: Dspace GmbH
Current assignee: Dspace GmbH
Priority date: 2020-12-15
Filing date: 2021-12-14
Publication date: 2023-10-25
Also published as: CN116569061A; WO2022129005A1; US11256032B1; JP2024501629A

Abstract

The invention relates to a programmable fiber-optic delay line for simulating spatial distances for an electromagnetic-wave-based surroundings sensor, which delay line comprises at least three optic transfer switches, and the transfer switches are interconnected by a multiplicity of optic fiber portions, as a result of which a continuous delay line having a plurality of different delay values is formed, wherein different delay values depend on the switch positions of the transfer switches, and wherein a terminal of a first transfer switch is connected to a third transfer switch while bypassing at least one second transfer switch.

Description

Programmable fiber optic delay line

The invention relates to a programmable fiber optic delay line and a target simulator with a programmable fiber optic delay line.

An environmental sensor is understood to mean an electronic control unit with at least one sensor-emitting element for emitting a transmission signal and a sensor-receiving element for receiving a reflection signal. These environmental sensors work with electromagnetic waves using a scanning principle - they emit an electromagnetic transmission signal and register the reflection signal reflected by environmental objects, from which they draw conclusions about the distance and/or speed and other properties of the environmental object. Most of these sensors are radar sensors, but lidar sensors can also be tested. The only fundamental difference between them is the frequency of the electromagnetic radiation used.

Generic environment sensors are used, for example, to obtain measurement data from the vehicle environment for emergency braking (AEB - Automatic Emergency Brake), distance control (ACC - Adaptive Cruise Control) and lane change assistants (LCS - Lane Change Support). These safety-relevant automatic controls require real-time information about the position and speed of approaching obstacles such as road users or stationary objects in the vehicle environment in order to intervene in vehicle guidance in good time and avoid collisions.

Typical environmental sensors include one or more emitting and receiving elements - such as radar antennas, logic for measuring and evaluating detected radar signals and interfaces to other control units in the vehicle. The radar device emits suitable electromagnetic waves in the radio frequency range - here the transmission signal - in a certain direction from its surroundings and waits for a reflected echo signal - here the reflection signal.

Sensors of this type are comparatively complex to test. Test benches are known from the prior art, as have been used for some time in the field of control unit tests. Test benches of this type are used, for example, to test automotive control units. The control unit is exposed to a simulated environmental scene with virtual environmental objects and its reaction evaluated. A common test situation is also functional tests and calibration tasks at the end of the production line of environmental sensors. In order to create a situation that is as realistic as possible in these test situations, the sensor control unit should be stimulated with real sensor signals so that it cannot distinguish the test situation from a "real" measurement situation. The demands on the accuracy of the simulated signal are high.

For this purpose, a simulated environmental scene is calculated using a real-time capable simulator system and physical signals are generated from this using a target simulator, to which the control unit to be tested is exposed. The trigger for the transmission of such a physical echo signal is the reception of the transmission signal transmitted by the control unit on the test bench side.

In order for the environmental sensor to be tested to achieve the desired measurement results based on a received simulated echo signal, a time delay must be imposed on the echo signal, in addition to other parameters such as a Doppler shift. The distance measurement of the environmental sensor is based on the transit time principle, with the environmental sensor measuring the signal transit time from emission to detection of the reflection signal and calculating the distance of the detected object from this.

One functionality of the target simulators used for testing environmental sensors is therefore the delay in the scanning signal emitted by the environmental sensors. Various techniques can be used for this, with a particularly advantageous technique being the delay by means of extended signal propagation paths through fiber optic lines in a fiber optic delay link.

Such a delay line is known, for example, from WO93/07508. Typical difficulties of the various solutions for delaying signals for simulating distances are regularly offering the smallest possible minimum distance that can be simulated, a large total distance that can be simulated, and a resolution in small steps of the distances that can be simulated between the two end points.

The object of the present invention is to further develop the prior art. The object is achieved by a programmable fiber-optic delay line with the features of claim 1 and by a target simulator with the features of claim 9.

Further advantageous refinements of the invention are the subject matter of dependent subclaims.

The fiber-optic delay line according to the invention has a number of optical transfer switches connected in series. An optical transfer switch is generally to be understood as a 2x2 switch with four terminals for coupling in optical signals, the terminals being arranged in pairs at the top and bottom of the switch. Such an optical transfer switch has up to five different switching states: each through-connected upper or lower terminals ("bar state"), or the connection of an upper and a lower terminal crosswise, alternatively in two orientations (left-top to right-bottom or vice versa), and the crosswise connection of the last two variants at the same time ("cross state"). It should be noted here that the terms “top” and “bottom” have been chosen arbitrarily to describe the mirror-symmetrical topology. The designations therefore have nothing to do with how the switch is positioned with respect to the earth's surface. It should also be noted that other variants of transfer switches can also be used and that not all switching states named above have to be used.

The optical transfer switch terminals described above are also called "pig-tails". They comprise short lengths of fiber optic cable with an optical coupling element via which an optical signal can be coupled into the switch. The length of these legs plays a role for the invention insofar as they contribute to the total delay of the optical delay line and thus increase the minimum delay that can be imposed. An optimization goal of such structures is therefore always to keep the overall length as short as possible with a minimum set delay. The number of switches placed in the delay line with this setting should therefore be minimized.

The delay line is now made up of optical transfer switches connected in series. To put it simply, the switches form a row. Legs that are next to each other will be on one side of the row - for example the lower or the upper, directly connected to each other. The designations "bottom/top" correspond here with the definition made above. The other side of the row is connected to each other by fiber optic delay elements of a predefined length.

The outer optical transfer switches in the series now form the input and the output of the delay line. The connection of a first transfer switch in the vicinity of a second transfer switch to a third transfer switch can be made by a delay element of a predefined length, or also directly by connecting the terminals. The advantage of this procedure is that the total number of switches can be reduced by this circumvention, or at least the minimum delay that can be simulated can be reduced.

The mode of operation of the delay line is now such that different combinations of delay lengths can be set by setting the switching states of the optical transfer switches. The switching statuses are set by a computer system which is connected to the optical transfer switches with suitable data connections and can influence the switching status of the transfer switches.

When designing the delay path, the length of the fiber-optic delay elements is determined in such a way that the desired different delay values can be set from a desired minimum to a maximum delay value by switching the different switching states. It should be noted that the number of delay increments increases with the number of switches used, but so does the size of the delay that is present anyway due to the delay path.

In this embodiment, the first switch is connected to the third switch, bypassing the second switch, by means of a delay element with a predefined length. One or more switches can be bypassed.

In a preferred embodiment, it is provided that the delay value of the programmable delay line can be adjusted by switching the fiber-optic delay elements in or out of the delay line, in which the optical transfer switches are computer-aided are controlled and the desired switching states of the optical transfer switch can be set.

In a preferred embodiment it is provided that the adjustable delay values of the programmable fiber optic delay line are specifically defined by their length being chosen such that the desired increments of the delay values can be set.

In one embodiment of the fiber-optic delay line for simulating spatial distances for an environment sensor based on electromagnetic waves, it has at least three optical transfer switches, the transfer switches being connected to one another by a large number of optical fiber sections, so that a continuous delay line with a plurality of different delay values is formed , and wherein different delay values depend on the switch positions of the transfer switches, and wherein a terminal of a first transfer switch is connected to a third transfer switch bypassing at least one second transfer switch.

An advantage of this embodiment is that the number of transfer switches can be kept lower than is usual in the prior art when a minimum delay is set.

A preferred embodiment of the invention provides that the programmable fiber-optic delay line has a first set of fiber-optic delay elements, each fiber-optic delay element connecting two transfer switches to one another.

A preferred embodiment of the invention provides that the optical delay line is constructed from a first row of optical transfer switches and a second row of optical transfer switches. It is provided that a switch assumes the function of a breakout switch, and a distributor transfer switch is provided. Breakout switches and splitter transfer switches, like all other switches, are optical transfer switches. They are connected in the fiber optic delay line in such a way that a signal either passes through all switches of the first and second row or only through the first number of transfer switches. This has the advantage that a large number of different delay values can be switched, and yet a minimum total delay, ie a minimum delay value of the programmable ones fiber optic delay line, is achieved. It is known from the prior art that for a delay path with N different delay elements, N+1 transfer switches must be used, which then all contribute to the minimum possible delay. The advantage of the invention is that only the transfer switches up to the breakout switch contribute to the minimum delay, while the delay path has a significantly higher number of transfer switches overall—namely the transfer switches of the first and second number together.

The choice of the position of the interruption in the delay line depends on the exact configuration of the delay line. For this, it must be considered which requirements are placed on the increment of the adjustable delay values. From this and based on the length of the connections that connect the terminals directly to each other ("pig-tails"), a statistically optimal position of the breakout switches results.

It is provided that the programmable fiber-optic delay line has a first row of optical transfer switches and a second row of optical transfer switches. The transfer switches of the first row are in each case lined up by connecting pairs of terminals, in that two terminals of two optical transfer switches are connected to one another by an optical delay element. In addition, two further terminals of these optical transfer switches are connected, e.g. as directly as possible via the connection of their pigtails. The same applies to the second row: their transfer switches are also lined up by connecting pairs of terminals by first terminals of two optical transfer switches being connected to one another by an optical delay element, and second terminals of these optical transfer switches are connected to each other.

In this case, the delay line has a distribution transfer switch which is assigned neither to the first nor to the second. A first terminal of the distribution transfer switch is connected to a third terminal of a second-row optical transfer switch, and a second terminal of the distribution transfer switch is connected to a third terminal of a first-row optical transfer switch provided as a breakout switch, so that the first-row optical transfer switches bypass the second Series is connectable to the distribution transfer switch. In other words, the distribution transfer switch has connections to both rows. Further, the first row of optical transfer switches is connected to the second row of optical transfer switches by connecting a fourth terminal of a first row optical transfer switch to a third terminal of a second row optical transfer switch, and wherein a third terminal of a first row optical transfer switch and a third terminal of the distribution transfer switch are designed as signal interfaces for coupling/decoupling optical signals.

A preferred embodiment of the invention provides that two of the fiber optic delay elements are chosen to be of the same length. This procedure is based on the knowledge that the production of optical fiber sections is subject to an inaccuracy that is in the range of the desired increment. Choosing two delay elements with the same length can make sense if the requirements placed on the maximum delay are lower than can be achieved with the number of switches and the delay elements selected. The goal is to achieve the same adjusted overall delay with several switching state combinations of the transfer switches. It is then possible, by duplicating two delay elements in the region of the larger delays, to create a possibility of calibrating the delay line before use in such a way that it meets the desired requirements for accuracy of the step size and accuracy of the simulated distance. For this purpose, all combinations possible with the delay line are set, subjected to a test signal and measured one after the other. The test signal is generated and measured back by an external device. The measurement results are then sorted according to the size of the delay and the delay distance is programmed in such a way that the selected - exact - delays can be set.

A preferred embodiment of the invention provides that the delay line is used in a target simulator. In very general terms, the environmental sensor to be tested can be a radar distance sensor, an ultrasonic sensor, or a lidar sensor. The target simulator has suitable simulator emission and reception elements. In the case of a radar distance sensor, these two elements are provided by radar antennas on the simulator side. Furthermore, a down-converter is provided, which down-converts the scanning signal emitted by the environmental sensor to be tested and received by the simulator receiving element to an intermediate frequency, as well as an optocoupler for converting the electrical Intermediate frequency signal into an optical signal. This signal can be coupled into the delay line according to the invention and the desired delay can be applied to it by program-controlled setting of the optical transfer switches. Furthermore, a further optocoupler is provided, which can convert the delayed signal into an electrical intermediate frequency signal. Furthermore, an amplifier can optionally be provided, with which the signal can be attenuated or amplified. The advantage of such a component is that more realistic echo signals can be generated. For example, a distant object is usually detected with a weaker echo signal than a closer object. The simulated echo signal can therefore be generated more realistically with an amplifier/attenuator component. Furthermore, a Doppler generator can be provided, which is set up to impress the signal with a Doppler frequency for simulating a relative speed with respect to the environmental sensor to be tested. Furthermore, an up-converter is provided, which up-converts the signal from the intermediate frequency to an RF frequency and makes it available for emission by the simulator emission element. The order of the components described here does not necessarily have to be adhered to - other combinations are also conceivable. Provision can also be made for the Doppler generator and the up-converter to be implemented in one component.

A preferred embodiment of the invention provides that the target simulator has a self-test function. It is provided here that the target simulator has a test signal generation component to generate a test signal and to couple it in at a point in the signal path within the target simulator—e.g. at the optocoupler, which converts the electrical signal into an optical signal, or at the down-converter. The test signal can be a laser, for example, or an electrical signal source. Furthermore, a signal detection component is provided, which measures the test signal and determines its signal propagation time. This measurement can be made at various points in the signal path, for example at the optocoupler, which converts the optical signal into an electrical signal, or at the upconverter. The advantage of a self-test function is that when using the target simulator it can be determined at any time whether the deceleration value provided by the delay line is the desired value. During operation of the device, changes in the internal components can occur over time, which can falsify the simulated echo signal. A high degree of accuracy and reliability is particularly important for tests at the end of production lines (“end of line” tests). of the simulation signal plays a role, since environmental sensors basically have safety-critical functionalities. The possibility of feeding in a test signal at different points in the signal path of the target simulator and being able to measure it back offers a flexible and time-saving possibility to keep the test quality constant.

In a preferred embodiment of the invention, the target simulator is installed in a test bench structure. This also includes means for bringing the simulator radiation elements of the target simulator to predetermined positions within the scenery perceived by the environmental sensor to be tested and, starting from these positions, to make an echo signal perceptible by the environmental sensor to be tested. This can be ensured by moving/rotating the environmental sensor under test relative to statically arranged simulator radiating elements, but also by moving the simulator radiating elements relative to a statically positioned environmental sensor under test, or by driving a plurality of simulator radiating elements arranged within the backdrop.

The invention is explained in more detail below with reference to the drawings. Similar parts are labeled with identical designations. The illustrated embodiments are highly schematic, i.e. the distances and the lateral and vertical extensions are not to scale and, unless otherwise stated, do not have any derivable geometric relationships to one another. It shows:

FIG. 1 shows a schematic view of an optical delay line according to the prior art

FIG. 2 shows a schematic view of a first embodiment according to the invention of a programmable delay path with three delay stages

FIG. 3 shows a schematic view of a second embodiment according to the invention of a programmable delay line with 14 delay stages FIG. 4 shows a schematic view of a third embodiment according to the invention of a programmable delay line with 14 delay stages

FIG. 5 shows a schematic view of a simulator device with a target simulator according to the invention

FIG. 1 shows a fiber-optic delay line as is known from the prior art. It includes four optical transfer switches SW1, SW2, SW3, SW4, which are arranged side by side. Adjacent lower terminals are connected to each other, respectively, while adjacent upper terminals are connected by Delay A, Delay B, and Delay C connectors. A signal can be coupled into the delay line through port 1 or port 2. The various switching states are shown in Figures 1A-1H. There are eight different delay stages and a minimum total delay "Minimum Delay", which is generated by the four transfer switches.

FIG. 2 shows a schematic representation of a delay line according to the invention with the various switching states, here having three transfer switches FS1, FS2, FS3 (3 bits). Adjacent switches are connected at their lower terminals and at their upper terminals to fiber optic delay elements A, B of a predefined length. The terminals at the top outside in the delay line are connected to each other with the delay element C in the vicinity of the transfer switch FS2. Figures 2A to 2E show the five different adjustable switching states of the three transfer switches FS1, FS2, FS3. Depending on the switching state, a signal injected through one of the input ports Port 1, Port 2 is delayed by the set amount. In Figure 2A, all switches are in the lower bar state - the connection between the lower terminals is through-connected. In this setting, the delay line provides the minimum possible delay, which results from three switches in this embodiment, not from four, as described in the example for FIG. Other switching states include switching states with the "cross state" - one or both terminal pairs are cross-connected. Figures 2B and 2C show two switches with a simple "cross state" and a "bar state" connections. They each provide the minimum delay plus the delay through delay element A (Figure 2B) or through delay element B (Figure 2C). This is indicated in the drawing by “minimum delay+delay A” in FIG. 2B and “minimum delay+delay B” in FIG. 2C, and there are comparable markings in the other figures. The maximum possible delay in this example is shown in Figure 2E, in which the switches each connect cross-terminal pairs through. The total delay here includes twice the minimum delay, since the signal traverses the three switches twice, and the delay through the fiber optic delay elements A, B, C of predefined length. The choice of the length of the various delay elements depends on the application for which the delay line is to be used. Depending on the application, more delays with a small amount may be desired - for example, if the environmental situation to be simulated mainly has objects in the vicinity of the environmental sensor to be tested. Conversely, it may be desirable to be able to set a minimum delay but still a large maximum delay for testing a long-range environmental sensor, such as a long-range radar. Here is an example: with a minimum delay of 1 meter, the following values are selected for the delay elements: A=5 meters, B=49 meters, C=100 meters. This results in the various adjustable total delays of 1 meter, 6 meters, 50 meters, 56 meters, 156 meters. Note that the delay resulting from the combination of delay elements A and B - here the 56 meters - results from the choice of A and B and cannot be further modified. In contrast to this delay, which is referred to as parasitic, all other delay values in this example can be influenced by choosing the length of the delay elements.

A further exemplary embodiment according to the invention is contained in FIG. 3, which here shows a delay line with 14 fiber-optic delay elements A, B, C, D, E, F, G, H, I, J, K, L, M, N and a total of 17 transfer switches FS1 up to FS17 (14 bit). In this example, the delay line is divided into two parts, one part having switches FS1 to FS7 and delay elements A to F, and the other part having switches FS8 to FS16 and delay elements G to N, and transfer switch FS17. The side-by-side switches of both parts are each connected to one another as already described for Figure 2 via their lower facing terminals, and to the delay elements via their upper facing terminals. The transition to the next part of the delay line begins with transfer switch FS7. Here is the bottom terminal of Transfer switch FS7 connected to transfer switch FS17 bypassing the second part of the delay line, while the upper terminal is connected to the lower terminal of transfer switch FS8. Unnecessary terminals at switches FS1, FS8, FS16 and FS17 remain open here. In this example, a total of 40,960 different combinations are possible with the delay line based on the 14 fiber optic delay elements. With the division of the delay section into two parts, the result when setting the minimum delay is that seven transfer switches instead of 15 transfer switches contribute to this.

FIG. 4 shows an example of the delay line according to the invention, which was already described in FIG. The figure also shows the coupling points FIBER RX and FIBER TX (corresponds to the designations port 1 and port 2 in the previous figures), via which the signal to be delayed is coupled into the delay line and coupled out again. The designation here indicates that the signal received by a simulator receiving element such as a radar receiving antenna and to be delayed is received by the FIBER RX coupling point and is coupled out through the FIBER TX coupling point or coupling point and is radiated again by the simulator radiation element. The connections between the transfer switches are drawn with different types of lines: dashed lines indicate fiber optic delay elements with a predefined length, dotted and solid lines indicate connections of the terminals of the transfer switches to each other.

The transfer switches FS1 to FS7, through which a signal to be delayed passes in succession in the delay line, are arranged next to one another, as already described in connection with FIG. The length of the connecting elements T1 and T2 between the transfer switches FS1 and FS2 and FS2 and FS3 are selected such that, matching the length of the delay elements D1, D2, D3, there is a constant increment between the delay values at the start of the delay path, while maintaining the minimum possible smallest delay. This allows the step size to be smaller than the length of the delay elements. The following values are given as an example: For a step width of 2.5 cm, D1 = 12.5 cm, D2 = 15 cm and D3 = 10 cm are selected. This means that T1 = 10 cm and T2 = 10 cm must be selected.

The transfer switches FS8 to FS16 are interwoven here. The transfer switches that follow one after the other within the delay line are in not next to each other in this part of the delay line. This arrangement is chosen to keep the connection between FS7 and FS17 as small as possible.

FIG. 5 shows a schematic representation of a simulator device with an environmental sensor to be tested SEN, which has a sensor emission and reception element S_ANT. The environmental sensor SEN is a radar distance measuring device that works with a frequency in the RF range. During operation outside of a simulator, the environmental sensor SEN determines a distance between the environmental sensor SEN and an object from the total propagation time of a signal. In particular, a transit time of the scanning signal SSEN to the object and a transit time of an echo signal reflected on the object back to the environmental sensor SSEN contribute to the overall transit time of the signal.

Furthermore, the schematic representation in Figure 5 includes a target simulator RTS, comprising a simulator emission and reception element SIM_ANT, a down-conversion mixer MIX1 suitable for down-conversion of an RF signal to an intermediate frequency, an optocoupler OPT1, the delay line according to the invention, an amplifier/attenuator AMP, a Doppler generator DOPP (optional, device for impressing a Doppler frequency), and an upconverter MIX2 suitable for upconverting an RF signal. The Doppler generator DOPP and the upconverter MIX2 can optionally also be implemented in one component.

In the simulator device RTS, the receiver is designed to receive a scanning signal SSEN emitted by the distance measuring device SEN in the form of electromagnetic waves SSEN via the simulator antenna SIM_ANT, to downconvert it to an intermediate frequency using the downmixer MIX1, the downconverted electrical signal using the optocoupler OPT1 in to transform an optical signal (for example to a frequency in the infrared range) and to couple it into the delay line DEL. Furthermore, the simulator device RTS is designed to transform the delayed signal by means of the optocoupler OPT2 into an electrical signal, which is amplified or attenuated to the desired power in the amplifier/attenuator AMP. The resulting signal can then be charged with a Doppler frequency and upconverted to the original RF frequency using the upconverter MIX2 and radiated using the simulator antenna SIM_ANT. Furthermore, a computer system COM is provided, which carries out an environment simulation and which is set up to control the delay line DEL and the optical transfer switch located therein and to set a delay predetermined by the simulation. This delay then corresponds to the relative distance of a simulated virtual object from the environmental sensor SEN to be tested.

Claims

Patent Claims:

1. Programmable fiber optic delay line (DEL) for simulating spatial distances for an environment sensor (SEN) based on electromagnetic waves, which has at least three optical transfer switches, wherein a first fiber optic delay element (A) has a first terminal of the first transfer switch (FS1) with a first terminal of the second transfer switch (FS2), and a second fiber optic delay element (B) connects a second terminal of the second transfer switch (FS2) to a first terminal of the third transfer switch (FS3), and a third fiber optic delay element (C) connects a second terminal of the third optical transfer switch (FS3) to a second terminal of the first optical transfer switch (FS1), so that the third optical transfer switch (FS3) is connected to the first optical transfer switch (FS1) bypassing the second optical transfer switch (FS2), and where a dri th terminal of the first transfer switch (FS1) is connected to a third terminal of the second transfer switch (FS2), and wherein a fourth terminal of the second transfer switch (FS2) is connected to a third terminal of the third transfer switch (FS3), and wherein a fourth terminal of the first transfer switch (FS1) and a fourth terminal of a third transfer switch (FS3) are designed as input or output ports (Port 1, Port 2) of the delay line, so that one between the signal interfaces (Porti, Port 2) for coupling/decoupling optical signals a continuous delay line is formed with a plurality of different delay values, the delay values being given by the switch positions of the transfer switches.

2. Programmable delay line (DEL) according to claim 1, wherein the optical transfer switches (FS1, FS2, FS3) have a plurality of switching states, and wherein a delay value of the delay line can be set by computer-assisted activation of the optical transfer switches (FS1, FS2, FS3), wherein by the driving of the optical transfer switch each one of the possible switching states can be set.

3. Programmable delay line (DEL) according to claim 1 or 2, wherein the fiber-optic delay elements (A, B, C) have a defined length, and wherein the increments of the adjustable delay values can be influenced by the choice of length.

4. Programmable delay line (DEL) according to one of the preceding claims, the fiber-optic delay elements (A, B, C) of different lengths.

5. Programmable fiber optic delay line (DEL) according to one of the preceding claims, comprising a first row of optical transfer switches (FS1, FS2, FS3, FS4, FS5, FS6, FS7) and a second row of optical transfer switches (FS8, FS9, FS10, FS11 , FS12, FS13, FS14, FS15, FS16), the transfer switches (FS1, FS2, FS3, FS4, FS5, FS6, FS7) of the first row being lined up by connecting pairs of terminals by connecting the first terminals of two optical transfer switches (FS1, FS2, FS3, FS4, FS5, FS6, FS7) are connected to each other by an optical delay element (A, B, C, D, E, F) and each second terminal of two optical transfer switches (FS1, FS2, FS3, FS4, FS5, FS6, FS7) are connected, whereby the transfer switches (FS8, FS9, FS10, FS11, FS12, FS13, FS14, FS15, FS16) of the second row are each lined up by connecting pairs of terminals by connecting the first terminals of two optical transfer switches (FS8, FS9 , FS10, FS11 , FS12, FS13, FS14, FS 15, FS16) by an optical one 17

Delay element (G, H, I, J, K, L, M, N) are connected to each other and second terminals of two optical transfer switches (FS8, FS9, FS10, FS11, FS12, FS13, FS14, FS15, FS16) are connected, and wherein the delay line (DEL) has a splitter transfer switch (FS17), wherein a first terminal of the splitter transfer switch (FS17) is connected to a third terminal of an optical transfer switch (FS16) of the second row, and wherein a second terminal of the splitter transfer switch (FS17) is connected to a third terminal of an optical transfer switch (FS7) of the first row (FS1, FS2, FS3, FS4, FS5, FS6, FS7) given as a breakout switch, so that the optical transfer switches of the first row bypassing the second row (FS2) with the distribution transfer switch (FS17) is connectable, and wherein the first row of optical transfer switches (FS1, FS2, FS3, FS4, FS5, FS6, FS7) can be connected to the second row of optical transfer switches (FS8, FS9, FS10, FS11, FS12 , FS13, FS14, FS15, FS16) in which a fourth optical transfer switch terminal (FS7) of the first row is connected to a third optical transfer switch terminal (FS8) of the second row, and wherein a third optical transfer switch terminal (FS1) of the first row and a third terminal of the distributor transfer switch (FS17) are designed as signal interfaces (Porti, Port2) for coupling/decoupling optical signals.

6. Programmable optical delay line (DEL) according to claim 5, wherein in a first operating mode of the delay line (DEL) the breakout transfer switch (FS7) is controlled in such a way that an optical signal bypasses the second row of optical transfer switches (FS8, FS9, FS10, FS11 , FS12, FS13, FS14, FS15, FS16) can be routed through the delay line (DEL) by setting the switching state of the breakout transfer switch (FS7) in such a way that the third terminal of the breakout transfer switch (FS7) is either connected to the first or second terminal of the Breakout transfer switch (FS7) is connected.

7. Programmable optical delay line (DEL) according to claim 6, wherein in a second mode of operation of the delay line (DEL) of the 18

Breakout transfer switch (FS7) is controlled such that an optical signal is passed through the first and second rows of optical transfer switches (FS1, FS2, FS3, FS4, FS5, FS6, FS7, FS8, FS9, FS10, FS11, FS12, FS13, FS14, FS15, FS16) can be conducted, in which the switching state of the breakout transfer switch (FS7) is set such that the fourth terminal of the breakout transfer switch (FS7) is connected to either the first or second terminal of the breakout transfer switch (FS7). Programmable optical delay line (DEL) according to one of the preceding claims, wherein at least two of the fiber optic delay elements (A, B, C, D, E, F, G, H, I, J, K, L, M, N) have the same length exhibit. Target simulator (RTS) for testing an environment sensor (SEN) based on electromagnetic waves, comprising an optical delay line (DEL) according to one of the preceding claims, further comprising at least one simulator receiving element (SIM_ANT), at least one simulator emitting element (SIM_ANT), a computer system (COM) , wherein the delay line (DEL) is connected to the simulator receiving element (SIM_ANT) on one side and to the simulator emitting element (SIM_ANT) on the other side, and a scanning signal (SSEN) of the environment sensor can be received by an environment sensor receiving element (S_ANT), and wherein the target simulator is set up to delay the sampled signal or a frequency-modified sampled signal (SSEN, SSEN') by means of the optical delay line (DEL), the switching states of the transfer switches and thus the delay value of the delay line (DEL) being able to be influenced by the computer system (COM). , and where the target simu lator (RTS) is set up to send the delayed sampling signal (SSIM) by means of the simulator radiating element (SIM_ANT) to the environmental sensor receiving element (S_ANT).

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