Vehicle-mounted millimeter wave radar target simulator and signal delay control method

Abstract

The invention discloses a vehicle-mounted millimeter-wave radar target simulator and a signal delay control method, the vehicle-mounted millimeter-wave radar target simulator comprises a PCB routing path switching module, a delay gating module and a signal compensation and output module, and the PCB routing path switching module comprises a plurality of groups of switches; the delay gating module comprises a multi-channel optical switch and two third switch units. The cooperative delay architecture of the PCB wiring path and the multi-channel optical switch breaks through the single link limitation in the prior art, the short-distance millimeter-level stepping delay is realized through PCB wiring, the long-distance stepping delay is realized by combining the optical fiber coil of the multi-channel optical switch, the full range is covered by the PCB wiring path and the multi-channel optical switch in a cooperative manner, the limitation of the minimum 3m of an optical fiber type simulator and the minimum 50m of a digital type simulator is solved, and the real-time performance of the simulator is improved. Meanwhile, the multichannel optical switch solves the problem of the shortest distance of the optical switch combination, so that the system is more concise, more convenient to maintain and lower in cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of radar testing, in particular to a vehicle-mounted millimeter wave radar target simulator and a signal delay control method. BACKGROUND

[0002] The vehicle-mounted millimeter wave radar is a core component of the intelligent networked automobile environment perception, and its ranging accuracy directly affects the safety of automatic driving decision. The vehicle-mounted millimeter wave radar target simulator is a key equipment for radar factory calibration and later maintenance. By delaying and attenuating the radar transmission signal, the target echo carrying the "distance, speed" information is simulated to realize the accurate verification of the radar performance. The current vehicle-mounted millimeter wave radar target simulator is mainly divided into two categories, both of which have a clear minimum distance limitation and cannot meet the near-distance calibration requirements of the vehicle-mounted scene. SUMMARY The present application aims to solve the technical problem that the existing vehicle-mounted millimeter wave radar target simulator cannot meet the near-distance calibration requirements of the vehicle-mounted scene. To this end, the present application provides a vehicle-mounted millimeter wave radar target simulator and a signal delay control method.

[0003] According to an embodiment of the present application, a vehicle-mounted millimeter wave radar target simulator is provided, comprising: A PCB trace path switching module, comprising a plurality of groups of switches, each group of switches comprising a first switch unit and a second switch unit, the first switch unit and the second switch unit each comprising a common end, a first selection end and a second selection end, the common end of the first switch unit serving as a first connection end of the group of switches, the common end of the second switch unit serving as a second connection end of the group of switches, the first selection end of the first switch unit being connected to the first selection end of the second switch unit through a first predetermined length of PCB trace, forming a first channel, the second selection end of the first switch unit being connected to the second selection end of the second switch unit through a second predetermined length of PCB trace, forming a second channel, wherein the plurality of groups of switches are connected in series through a third predetermined length of PCB trace through the first connection end and the second connection end, and one of the third switch units is connected to the second connection end; A delay gating module, comprising a multi-channel optical switch and two third switch units, the multi-channel optical switch being integrated with a plurality of groups of optical fiber coils of different lengths, each group of optical fiber coils corresponding to a specific delay time The basic delay unit is determined by the length of the optical fiber, and the two third switch units are connected through a third predetermined length of PCB trace and a fourth predetermined length of PCB trace, respectively forming a signal compensation path and a multi-channel optical switch path, and the multi-channel optical switch is connected in series in the multi-channel optical switch path. A signal compensation and output module is connected in series between the PCB wiring path switching module and the delay gating module.

[0004] According to the vehicle-mounted millimeter wave radar target simulator provided by the embodiment of the application, at least the following beneficial effects are achieved: The cooperative delay architecture of the PCB wiring path+multi-channel optical switch of the application breaks through the single-link limitation of the prior art, realizes near-distance millimeter-level step delay through PCB wiring, realizes long-distance step delay through the fiber coil of the multi-channel optical switch, and cooperatively covers the full range, solves the limitations of the optical fiber type simulator (minimum 3m) and the digital type (minimum 50m), and solves the shortest distance problem of the optical switch combination, so that the system can be more concise, maintenance is more convenient, and the cost is lower.

[0005] According to some embodiments of the application, the first preset length is much smaller than the second preset length, so that the first channel is a direct path and the second channel is a delay path.

[0006] According to some embodiments of the application, for multiple groups of switches, the corresponding second preset lengths are increased according to binary weights.

[0007] According to some embodiments of the application, the number of the multiple groups of switches is N groups, N is an integer greater than 1, and the corresponding second preset lengths of each group are L, 2L, 4L, …, wherein L is a unit length.

[0008] According to some embodiments of the application, by independently controlling two switch units in each group of switches to synchronously switch to the first selection end or the second selection end, a plurality of total path lengths stepped by L from 0 to can be combined.

[0009] According to some embodiments of the application, the signal compensation and output module includes an attenuator, an amplifier, and an equalizer.

[0010] According to some embodiments of the application, the PCB wiring path switching module, the signal compensation and output module, and the delay gating module are integrated on a PCB.

[0011] According to a signal delay control method according to the second aspect of the embodiment of the application, a vehicle-mounted millimeter wave radar target simulator according to any one of claims 1 to 7 is used, and the signal delay control method comprises the following steps. According to the target delay amount, determine the channels to be selected by each group of switches, the multi-channel optical switch, and the two third switch units connected to the signal main path. The first switch unit and the second switch unit in each corresponding group of switches are sent a synchronous control signal, so that their common ends are connected to the first selection end or the second selection end at the same time, and two third switch units are sent a synchronous control signal at the same time, so that they are connected to the signal compensation path or the multi-channel optical switch path, and the multi-channel optical switch is sent a synchronous control signal at the same time, so that it is connected to the optical fiber coil of the required length. The total transmission length of the control signal in the path is controlled by combining the control of the multiple groups of switches, the multi-channel optical switch and the channel selection of the two third switch units.

[0012] According to some embodiments of the present application, for simulating a near target, the delay paths that need to access the main signal path according to the target delay amount specifically include: The two third switch units are controlled to be sent a synchronous control signal at the same time, so that they are connected to the signal compensation path.

[0013] For simulating a far target, the delay paths that need to access the main signal path according to the target delay amount specifically include: The two third switch units are controlled to be sent a synchronous control signal at the same time, so that they are connected to the multi-channel optical switch path.

[0014] Other features and advantages of the present application will be set forth in the description that follows, and in part will become apparent to those skilled in the art upon examination of the following or can be learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0015] The present application will be further described below in conjunction with the accompanying drawings and embodiments, in which: Figure 1 It is a structural schematic diagram of a vehicle-mounted millimeter wave radar target simulator; Figure 2 It is a flowchart of a signal delay control method. DETAILED DESCRIPTION

[0016] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the accompanying drawings, in which the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.

[0017] In the description of the present application, it should be understood that the orientation description, such as the indications of up, down, etc., is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0018] In the description of the present application, more refers to more than two. If the first, the second is described for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the sequence of indicated technical features.

[0019] In the description of the present application, unless otherwise explicitly limited, the words such as setting, installation, connection and the like should be understood broadly, and those skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical scheme.

[0020] The technical scheme of the present application will be described below in conjunction with the drawings. Obviously, the following described embodiments are part of the embodiments of the present application, not all embodiments.

[0021] Current vehicle-mounted millimeter wave radar target simulator is mainly divided into two categories, both of which have a clear minimum distance limitation, and cannot meet the near distance calibration requirements of vehicle-mounted scene: 1. Digital vehicle-mounted millimeter wave radar target simulator Technical principle: through FPGA, DAC / ADC and other electronic devices, the radar signal is processed by digital delay to generate simulated target echo.

[0022] Core limitation: the minimum simulation distance is generally more than 50m, which cannot cover the near distance scene of vehicle-mounted.

[0023] The root cause is that digital devices have fixed signal processing delay: the signal sampling clock period of FPGA, the conversion time of DAC / ADC is superimposed, which leads to the lower limit of the distance corresponding to the signal delay Cannot break through 50m; and the bandwidth of this type of simulator is limited by DAC / ADC.

[0024] 2. Optical fiber type vehicle-mounted millimeter wave radar target simulator Technical principle: taking optical fiber as the signal transmission medium, through the link of "electro-optical converter→optical switch array→optical-electric converter", the signal delay corresponding to the length of optical fiber is used to realize target distance simulation (reference is ZA0500A of DEK-Tech).

[0025] Current optimal parameters: the maximum simulation distance of the industry mainstream product (such as ZA0500A) is 400m, and the minimum simulation distance can only reach 3m, with a step precision of 1cm. It is the strongest solution for near distance simulation, but still has core pain points.

[0026] (1) Physical spacing limitation of optical switch array: limited by the packaging size of optical switch Due to the constraints of fiber optic fusion splicing technology, the minimum actual distance between adjacent optical switches must be at least 30cm (if it is shorter than 30cm, welding technology currently does not support welding); taking a transmission link composed of 9 optical switches as an example, the minimum distance corresponding to the spacing between the optical switches alone reaches... .

[0027] (2) Fixed time consumption of electro-optic / photoelectric conversion devices: Electro-optic converters are required in the link, and the total signal response time of these devices is approximately Corresponding to a fixed distance delay .

[0028] (3) Distance limit caused by link loss superposition: The superposition of the above optical switch spacing (1.35m) and conversion delay (0.75m) makes it impossible for the minimum distance of the fiber optic simulator to break through 2.1m. Due to the slight delay of other components (such as signal amplifiers), the actual product's minimum distance is finally set at 3m, which cannot be further reduced.

[0029] Therefore, refer to Figure 1 This application provides an embodiment of a vehicle-mounted millimeter-wave radar target simulator, comprising: The PCB trace path switching module includes five sets of switches. Each set of switches includes a first switch unit and a second switch unit. The first switch unit and the second switch unit are located in... Figure 1 All of these refer to SPDT1. The first switch unit and the second switch unit each include a common terminal, a first selection terminal, and a second selection terminal. The common terminal of the first switch unit serves as the first connection terminal of the group of switches, and the common terminal of the second switch unit serves as the second connection terminal of the group of switches. The first selection terminal of the first switch unit and the first selection terminal of the second switch unit are connected by a PCB trace of a first preset length to form a first channel. The second selection terminals of the first switch unit and the second selection terminals of the second switch unit are connected by a PCB trace of a second preset length to form a second channel. The five groups of switches are connected in series sequentially through their first connection terminals and second connection terminals and a PCB trace of a third preset length.

[0030] Specifically, the first preset length is much smaller than the second preset length, making the first channel a direct path and the second channel a delayed path. For multiple sets of switches, the corresponding second preset lengths increase in binary weights.

[0031] Five sets of switches are used to combine and switch PCB traces. The first channel of each set is extremely short and negligible in length. The second channels are 1cm, 2cm, 4cm, 8cm, and 16cm respectively. By independently controlling the channel selection of each SPDT1, flexible switching with a precision of 1cm can be achieved.

[0032] The delay gating module includes a multi-channel optical switch and two third switch units, both referred to as SPDT2 in the figure, and the multi-channel optical switch is integrated with multiple groups of optical fiber coils of different lengths, each group of optical fiber coils corresponding to a specific delay time The basic delay unit is determined by the length of the optical fiber, and the two third switch units are connected by a third preset length of PCB trace and a fourth preset length of PCB trace, respectively forming a signal compensation path and a multi-channel optical switch path, and the multi-channel optical switch is connected in series in the multi-channel optical switch path. One of the third switch units is connected to the second connection end.

[0033] The input end is connected to the delay link side of the front-end SPDT2, and multiple groups of optical fiber coils of different lengths are integrated inside, such as the "subsequent optical fiber coils" marked, each group of coils corresponding to a specific delay time The basic delay unit is determined by the length of the optical fiber, and the two third switch units are connected by a third preset length of PCB trace and a fourth preset length of PCB trace, respectively forming a signal compensation path and a multi-channel optical switch path, and the multi-channel optical switch is connected in series in the multi-channel optical switch path. One of the third switch units is connected to the second connection end. The output end is connected to the end SPDT2. As a "delay step gating core", by gating different optical fiber coils, precise step-by-step delay simulation of the target distance is realized (such as = 32 cm). The core advantage of the multi-channel optical switch is that it eliminates the shortest distance problem of multiple optical switch combinations. Multiple optical switch combinations require at least 30 cm of distance for each level to be welded, while the shortest distance of the multi-channel optical switch is only the shortest distance of one group of optical switches. At the same time, compared with the equivalent optical switch combination, the cost of the multi-channel optical switch also has an advantage.

[0034] The optical fiber coils are wound into coils and integrated inside the multi-channel optical switch, and the length difference of the optical fiber of each group of coils is distinguished by multiples of τ. The transmission delay of the optical signal in the optical fiber is used to convert the distance information into delay time, and realize the simulation of the radar target distance.

[0035] The signal compensation and output module is connected in series between the PCB trace path switching module and the delay gating module. The signal compensation and output module includes an attenuator, an amplifier, and an equalizer to compensate for the signal power loss of the PCB trace path and correct the flatness of the signal, etc. In Figure 1 the signal compensation path in the signal compensation and output module, the power flatness of the signal will not change when the SPDT2 is switched.

[0036] Adopting multi-channel electric switch and optical switch instead of few-channel switch combination, reducing wire type from 3 to 2, reducing total number of wire of channel equipment, relieving wiring conflict, reducing wiring welding complexity, improving production efficiency, improving utilization rate of internal space of equipment, compressing volume; removing cable type wire, reducing mutual coupling of PCB wiring and cable of system; one less cable needs to be maintained, and positioning speed and difficulty of re-melting of problems such as optical switch disconnection are reduced, single multi-channel optical switch is lower in cost than combined link optical switch, so that the whole vehicle-mounted millimeter wave radar target simulator troubleshooting time is shortened, maintenance efficiency is improved, equipment maintenance cost is reduced, and overall scheme cost is reduced; in addition, because multi-channel optical switch is used, the required volume is smaller, and finally the equipment volume can be reduced, more scenes can be adapted, and the scene that requires equipment volume can be handled.

[0037] Specific hardware composition and connection PCB wiring path switching module: Multiple SPDT1 switches (note that the working frequency is selected according to the specific radar, the bandwidth is more than 5GHz, the insertion loss is less than 1dB, and the isolation is more than 50dB), and the PCB wiring is designed in steps of “1cm, 2cm, 4cm, 8cm, 16cm” , impedance 50 , Rogers RO5880 board).

[0038] Signal compensation module: amplifier (note that the working frequency is selected according to the specific radar, the bandwidth is more than 5GHz, and the amplifier power selection needs to be determined in combination with the attenuator and equalizer simulation), attenuator, equalizer, connected in series at the end of the PCB wiring path.

[0039] Delay gating module: Multi-channel optical switch, the number of channels is more than 12, the difference of insertion loss of different channels is determined according to the overall flatness requirement of the project, generally within 0.5dB, and dynamic adjustable equalizer can be selected for strict requirements, but this will cause cost to rise. The switching time is determined according to the specific radar project, generally <1ms.

[0040] Optical fiber type: single-mode optical fiber, , the bending radius is determined according to the volume of the simulator, the smaller the better, and the final volume is small.

[0041] Other components: The signal mixing is reduced to , reducing the selection difficulty of subsequent amplifier equalizer and other parts; Host computer: providing control signals including multi-channel optical switch, SPDT switch, etc.

[0042] The PCB wiring path switching module, the signal compensation and output module, and the delay gating module are integrated on the PCB. The switch of the PCB wiring path and the wiring are integrated on the same circuit board, the optical fiber coil of the optical switch selecting path is integrated in the multi-channel optical switch, and the number of external wires and modules is reduced. The number of internal wires of the device is reduced, the connection between the modules does not need external cables, and complex wiring is not needed during deployment; during maintenance, one type of wire is saved, and the complexity of the optical switch fusion part is directly reduced. And the PCB board can have fewer interfaces. The degree of impedance mismatch is reduced, and the signal interference and loss problem is relieved to a certain extent.

[0043] In other embodiments, the number of groups of switches is N groups, N is an integer greater than 1; the second preset length corresponding to each group is L, 2L, 4L, …, , wherein L is the unit length. By independently controlling the two switch units in each group of switches to synchronously switch to the first selection end or the second selection end, a plurality of total path lengths from 0 to , with L as the step, can be combined.

[0044] Referring to Figure 2 , the application also provides an embodiment of a signal delay control method, which adopts a vehicle-mounted millimeter wave radar target simulator according to any one of the above, and the signal delay control method comprises the following steps: Step 100: determining the channels that should be selected by each group of switches, the multi-channel optical switch, and the two third switch units connected to the signal main path according to the target delay amount; Step 200: sending a synchronous control signal to the first switch unit and the second switch unit in the corresponding group of switches to simultaneously connect the common end to the first selection end or the second selection end, and simultaneously sending a synchronous control signal to the two third switch units to connect to the signal compensation path or the multi-channel optical switch path, and simultaneously sending a synchronous control signal to the multi-channel optical switch to connect to the optical fiber coil with the required length; Step 300: controlling the total transmission length of the signal in the path by combining the channel selection of the multiple groups of switches, the multi-channel optical switch, and the two third switch units.

[0045] The application realizes full-range target simulation through the cooperative switching of the “PCB wiring path (short distance), optical switch selection path (long distance), and signal compensation path (amplitude / frequency compensation)”. The specific process is as follows: 1. Short-distance target simulation (about 1 m) Step 1: path switching The external control signal (upper computer sends instructions) makes the signal compensation path of SPDT2 conductive, without passing through the multi-channel optical switch; Step 2: delay and compensation After the inherent delay of the signal through the PCB, the power loss is compensated by the amplifier, the frequency distortion is compensated by the equalizer, and the amplitude is balanced by the attenuator, forming a stable very close range echo signal.

[0046] Step 3: Signal output The processed signal is transmitted to the end SPDT2, which is turned on to the radar receiving end, completing the near-range target echo simulation.

[0047] 2. Long-range target simulation Step 1: Path combination switching The external control signal makes SPDT2 select the optical switch to select the path, and the signal passes through the multi-channel optical switch.

[0048] Step 2: Delay superposition and compensation The delay of the very close range short wire and the minimum of the long range The delay superposition of the coil forms a near-range simulation of about 1.6m; through the signal switching algorithm of the upper computer, for example, when simulating a near range, the simulation of a 31cm signal is through the selection of the second path of all channels of the PCB wire path. When switching to a long-range target simulation, SPDT2 switches the path, and at the same time, all channels of the PCB wire path select the first path, completing the simulation of a 32cm signal. At the same time, the signal compensation path works synchronously to ensure that the amplitude and frequency characteristics match the requirements of the radar.

[0049] Step 3: Signal output The signal after superposition and delay is output to the radar through the end SPDT1, completing the near-range target echo simulation.

[0050] The cooperative delay architecture of this method "PCB wire path + multi-channel optical switch" breaks through the "single link limitation" of existing technology, realizes near-range millimeter-level step delay through PCB wire, and realizes long-range step delay through multi-channel optical fiber coil. The combination of the two covers the full range, solves the limitations of "minimum 3m" of optical fiber simulator and "minimum 50m" of digital type, and at the same time, the multi-channel optical switch solves the shortest distance problem of optical switch combination, making the system more concise, easier to maintain, and lower in cost; only two types of wires "PCB wire + single-mode optical fiber" are retained, the number of internal wires of the equipment is reduced; to a certain extent, wiring conflicts and signal crosstalk are eliminated.

[0051] It should be understood that portions of the present application can be implemented with hardware, software, firmware, or a combination thereof. In the above embodiments, several steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any of the following technologies, known in the art, or a combination thereof, can be used: discrete logic circuitry having logic gates for implementing logic functions upon an application of data signals, application specific integrated circuits having appropriate combinational logic gates, programmable gate arrays (PGA), field programmable gate arrays (FPGA), and the like.

[0052] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" etc. means that the particular feature, structure, material or characteristic being described is included in at least one embodiment or example of the present application. The illustrative description of the above terms in the present specification is not necessarily referring to the same embodiment or example. Moreover, the described particular feature, structure, material or characteristic can be combined in any one or more embodiments or examples in a suitable manner.

[0053] The above detailed description of the embodiments of the present application is made in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present application.

Claims

1. A vehicle mounted millimeter wave radar target simulator, characterized by, The application relates to a signal delay control method and a signal delay control device. The PCB trace path switching module comprises multiple groups of switches, each group of switches comprising a first switch unit and a second switch unit, the first switch unit and the second switch unit each comprising a common terminal, a first selection terminal and a second selection terminal, the common terminal of the first switch unit serving as a first connection terminal of the group of switches, the common terminal of the second switch unit serving as a second connection terminal of the group of switches, the first selection terminal of the first switch unit being connected to the first selection terminal of the second switch unit through a first preset length of PCB trace, forming a first channel, the second selection terminal of the first switch unit being connected to the second selection terminal of the second switch unit through a second preset length of PCB trace, forming a second channel, wherein the multiple groups of switches are connected in series through a third preset length of PCB trace through the first connection terminals and the second connection terminals. The delay gating module comprises a multi-channel optical switch and two third switch units, the multi-channel optical switch is integrated with multiple groups of optical fiber coils with different lengths, and each group of optical fiber coils corresponds to a specific delay time The two third switch units are connected by a third preset length of PCB trace and a fourth preset length of PCB trace respectively, to form a signal compensation path and a multi-channel optical switch path respectively, the multi-channel optical switch is connected in series in the multi-channel optical switch path, and one of the third switch units is connected with the second connection end. The signal compensation and output module is connected in series between the PCB trace path switching module and the delay gating module.

2. The vehicle mounted millimeter wave radar target simulator of claim 1, wherein, The first preset length is much smaller than the second preset length, so that the first channel is a direct path and the second channel is a delay path.

3. The vehicle mounted millimeter wave radar target simulator of claim 2, wherein, The second preset length of each group of switches increases in binary weight.

4. The vehicle mounted millimeter wave radar target simulator of claim 3, wherein, The number of the plurality of groups of switches is N groups, N is an integer greater than 1; the second preset lengths corresponding to each group are L, 2L, 4L, …, respectively, wherein L is a unit length.

5. The vehicle mounted millimeter wave radar target simulator of claim 4, wherein, By independently controlling the two switch units in each group of switches to synchronously switch to the first selection end or the second selection end, a plurality of total path lengths stepped by L from 0 to can be combined.

6. The vehicle mounted millimeter wave radar target simulator of claim 1, wherein, The signal compensation and output module comprises an attenuator, an amplifier and an equalizer.

7. The vehicle mounted millimeter wave radar target simulator of claim 1, wherein, The PCB trace path switching module, the signal compensation and output module and the delay gating module are integrated on a PCB.

8. A signal delay control method using the vehicle-mounted millimeter wave radar target simulator according to any one of claims 1 to 7, characterized by, The signal delay control method comprises the following steps: According to a target delay amount, determining the channels to be selected by each group of switches, a multi-channel optical switch and two third switch units connected to a main signal path; Sending a synchronization control signal to the first switch unit and the second switch unit in each group of switches so that the common terminals are connected to the first selection terminals or the second selection terminals at the same time, and sending a synchronization control signal to the two third switch units so that the two third switch units are connected to a signal compensation path or a multi-channel optical switch path, and sending a synchronization control signal to the multi-channel optical switch so that the multi-channel optical switch is connected to an optical fiber coil with a required length; Controlling the channel selection of the multiple groups of switches, the multi-channel optical switch and the two third switch units by combination, and controlling the total transmission length of the signal in the path.

9. The signal delay control method according to claim 8, characterized by, For simulating a near-distance target, the step of determining the delay paths connected to the main signal path according to the target delay amount comprises the following step: Controlling the two third switch units to be connected to the signal compensation path at the same time.

10. The signal delay control method according to claim 8, wherein For simulating a far-distance target, the step of determining the delay paths connected to the main signal path according to the target delay amount comprises the following step: Controlling the two third switch units to be connected to the multi-channel optical switch path at the same time.

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