Multipath simulation test device
By simulating multipath signals using fiber optic transmission networks and photoelectric converters, the problems of high cost and insufficient flexibility in multipath signal simulation in traditional methods are solved. This enables efficient multipath effect testing in standard open test sites, meets military/national standards, and reduces testing costs.
Patent Information
- Application Number
- CN202511329346.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-17
- Publication Date
- 2025-11-07
AI Technical Summary
Existing technologies struggle to efficiently simulate multipath signals in standard open test sites. Traditional methods are costly, lack flexibility, cannot accurately control multipath delay, amplitude, and phase characteristics, and have poor test repeatability.
By combining an optical fiber transmission network with a radio frequency signal source and an optoelectronic converter, the multipath effect of radio signals is simulated through optical fiber delay. The optical fiber transmission network and optoelectronic converter are used to simulate multipath signals, and the delay, amplitude and phase of the multipath signals are precisely controlled by a vector network analyzer.
It enables efficient and low-cost simulation of multipath effects in standard open testing sites, improving the accuracy and repeatability of testing, meeting military/national standards requirements, reducing testing costs, and enhancing testing flexibility.
Smart Images
Figure CN120915401A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of radio monitoring direction finding technology, and particularly relates to a multipath simulation test device. BACKGROUND
[0002] The multipath effect is a main interference source in wireless communication and direction finding systems. Especially in complex electromagnetic environments (such as cities, valleys, and oceans), after the signal is reflected and diffracted by different paths to reach the receiving end, the direction finding accuracy will be reduced. Especially in the fields of short-wave communication, unmanned aerial vehicle control, and maritime radar, the multipath interference of constant modulus signals is serious, the direction finding accuracy is low, and the performance of traditional direction finding algorithms is significantly reduced in the scene of high multipath delay (1-6.67 μs). The fundamental reason for the inaccurate direction finding is the multipath propagation of signals. Figure 1 As shown in the figure, the high mountains, valleys, and ocean surfaces are very easy to produce multipaths with a wave path difference of 300 m-2000 m and above. In the field of radio monitoring direction finding, the standard open test field with a diameter of 200 m is still using the traditional long cable to simulate the multipath signal. Due to the problems of large attenuation, large cable volume, and high cost of 300 m-2000 m and above long cables, it is still impossible to simulate large-scale multipaths in the radio monitoring direction finding standard open test field.
[0003] To solve the problem of inaccurate testing of on-site multipath signals, it is urgent to develop a direction finding method and test system that is resistant to multipath interference. However, the existing test methods mostly rely on product erection on-site field measurement or general channel simulator, which has the following problems: 1) the cost of on-site field test of product erection is high: it needs to frequently deploy real scenes, which is limited by weather and topographic differences of different erection sites, and the test repeatability is poor. 2) it does not meet the existing radio monitoring direction finding test requirements, which need to be carried out in an open test field that meets the relevant standards. 3) the traditional simulator has insufficient flexibility: it is difficult to accurately control the multipath delay, amplitude, and phase characteristics, especially lacking the ability to simulate constant modulus multipaths (constant amplitude and variable delay).
[0004] In addition, the traditional two-multipath signal direction finding accuracy test layout is shown in Figure 2 , which arranges the turntable, the system under test, the transmitting system 1, and the transmitting system 2 according to the requirements of Figure 3 , wherein the input signals of the transmitting system 1 and the transmitting system 2 are evenly distributed to the transmitting antennas of the two transmitting systems by a power divider from the same signal source system, and the transmitting system connection is shown in Figure 2The existing conventional long cable analog multipath scheme has the following problems: 1) The cost of field test in the product erection site is high: real scenes need to be frequently deployed, and the test repeatability is poor due to the limitation of weather and the difference of terrain in different erection sites. 2) It does not meet the existing radio monitoring direction test which needs to be carried out in an open test site meeting the relevant standards. 3) Low-cost alternative scheme: the conventional multipath simulation needs to use multiple signal sources and cables, and the delay control usually has the characteristics of large volume, narrow bandwidth, large loss, unstable phase, and high cost, which makes it difficult to simulate the required multipath signal in the standard open test field and carry out the test. 4) The flexibility of the traditional simulator is insufficient: it is difficult to accurately control the multipath delay, amplitude and phase characteristics, especially the lack of targeted simulation capability for constant modulus multipath (amplitude constant, time delay variable). The conventional open test site cannot simulate multipath of different distances due to the diameter of 200m. SUMMARY
[0005] To solve the problems existing in the prior art, the purpose of the present application is to provide a multipath simulation test device, which is mainly used for multi-scale multipath compression and direction reconstruction of multipath simulation test in a standard open test field (OATS).
[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: a multipath simulation test device, comprising: a standard open test field, the standard open test field comprising a measured system provided on a turntable and a plurality of transmitting systems provided on the periphery of the measured system, characterized in that it further comprises a radio frequency signal source and a power divider connected with the radio frequency signal source, and the power divider is connected with the transmitting antennas of the transmitting systems through a multi-path optical fiber transmission network.
[0007] As a further improvement of the present application, each of the optical fiber transmission networks comprises an E / O electric-optical converter, an adjustable optical fiber, an O / E optical-electric converter and a gain controller connected in sequence between the power divider and the transmitting antennas of the transmitting systems.
[0008] As a further improvement of the present application, the power divider and the transmitting antennas of the transmitting systems are further provided with a vector network analyzer.
[0009] As a further improvement of the present application, the distance between the transmitting antenna erection position of the transmitting system and the receiving antenna erection position of the measured system is D, and the distance between the transmitting antenna erection position of the transmitting system and the edge of the standard open test field is d, wherein D≥10λ and d≥5λ, and λ refers to the wavelength of the lowest test frequency of the measured system.
[0010] As a further improvement of the present application, the polarization mode and erection height of the transmitting antennas of the transmitting system and the receiving antennas of the receiving system are consistent.
[0011] As a further improvement of the present application, the center point of the receiving antenna of the measured system coincides with the center point of the turntable.
[0012] In order to simplify the test and improve the testability of multipath, the present application designs a multi-scale multipath compression and direction reconstruction multipath simulation test device mainly for standard open test field (OATS), which can simulate the multipath effect generated when radio waves are transmitted in high mountains, valleys, cities, high buildings and ocean surfaces above several kilometers, and can perform direction reconstruction at any angle in a limited OATS standard open test field with a fixed diameter of 200 meters, so as to finally realize the test of multipath effect at any distance and any angle in a limited OATS standard open test field, and ensure the repeatability and compliance of the test.
[0013] The present application has the following advantages:
[0014] The present application provides a multi-scale multipath compression and direction reconstruction multipath simulation test device system mainly for standard open test field (OATS), which is the first in the field of radio monitoring and direction finding, and meets the requirements of military standard / national standard double standard open test field test, and reduces the cost of standard open test field reconstruction by more than 90% due to the small size and low cost of the photoelectric conversion module + optical fiber (the cost of the photoelectric conversion kit is greatly reduced compared with the cable solution), and can be widely used in the monitoring and direction finding function performance test of the monitoring and direction finding receiver system on the standard open test field (OATS), and can also be applied to the test of various combination scenes of multipath elevation angle. BRIEF DESCRIPTION OF DRAWINGS
[0015] Figure 1 It is a multi-path generation system schematic diagram;
[0016] Figure 2 It is a schematic diagram of a traditional two multi-path signal transmission system;
[0017] Figure 3 It is a general test field layout schematic diagram of a standard open test field;
[0018] Figure 4 It is a system block diagram of the multi-path simulation test device in the embodiment of the present application. DETAILED DESCRIPTION
[0019] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.
[0020] EMBODIMENT
[0021] This embodiment aims to design a multipath simulation test device for multi-scale multipath compression and orientation reconstruction, primarily used in standard open-field test ranges (OATS). Multipath effects occur when radio waves propagate through mountains, canyons, urban high-rises, and ocean surfaces at altitudes of hundreds to thousands of meters. Traditional multipath effect testing can only be performed on-site.
[0022] This embodiment designs a method to directly modulate radio signals into optical signals, delay them through optical fibers, and then convert the optical signals back into radio signals. These radio signals are then transmitted via cable and antenna at different angles. The time delay of the radio signals at different distances is simulated using optical fibers of varying lengths. The direction of arrival of the multipath signals at different angles is simulated by using a turntable in an existing standard open test area corresponding to the transmission point. The signal amplitude is adjusted by an adaptive amplifier that performs electro-optical and photoelectric conversions to ensure amplitude stability. This allows for the simulation of multipath effects at the required standard angles and with different time delays within a fixed-diameter 200-meter OATS standard open test area. Ultimately, this enables precise multipath effect testing at any distance and angle within a limited OATS standard open test area, ensuring test repeatability and compliance.
[0023] Standard open test range orientation finding test layout as follows Figure 3 As shown, according to Figure 3 Set up the turntable, the system under test (DUT), and the transmitting system, ensuring that the center point of the DUT's antenna coincides with the center point of the turntable. The distance between the transmitting system's antenna and the DUT's antenna should be D (D not less than 10λ, where λ refers to the wavelength of the lowest test frequency of the DUT), and the distance from the edge of the testing area should be d (d not less than 5λ). The polarization and mounting height of the transmitting system's antenna should be consistent with those of the DUT.
[0024] The system block diagram of the multi-path simulation test device designed in this embodiment, primarily for multi-scale multipath compression and orientation reconstruction in standard open-field OATS, is as follows: Figure 4 As shown, the core requirement of multipath simulation testing is the precise control of the amplitude, phase, and time delay of signals from multiple paths. This embodiment designs a distributed radio frequency optical signal ROF conversion via an optical fiber transmission network to precisely control the time delay, phase synchronization, and power distribution of multiple signals (simulating direct waves and reflected waves) in an open field. The solution of this embodiment is as follows... Figure 4 As shown, to address the requirements of large-scale deployment and long-distance phase stability assurance solutions in open areas, the following approaches are abandoned: Figure 2 This embodiment supports analog multipath transmission via long cables after RF signal power division, or analog multipath transmission using long cables with common-phase reference for multiple signal sources. Figure 3The standard open test field direction finding test layout is adopted, the multipath signal is simulated by single signal source power division mode, the traditional long radio frequency cable multipath simulation equipment is simplified by ROF, the ROF radio frequency direct light modulation technology is adopted for optical fiber transmission, different lengths of optical fiber combinations are determined according to the multipath test ability limit, the distribution topology structure combination scheme of 1-n multipaths is formulated according to the optical fiber length demand of common multipath signals, the different multipath channels are calibrated by using the vector network in the whole independent link before testing, so that the expensive delay fine tuning equipment does not need to be added, the gain controller is set to ensure that the amplitude meets the variable requirements of the test, and the system architecture adopts the distributed coverage transmission network to facilitate the synthesis of multipath test signals in different angle directions in the standard open test field.
[0025] The above-described embodiments only express the specific implementation of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the patent of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the protection scope of the present application.
Claims
1. A multipath analog test apparatus comprising: The standard open test field comprises a tested system arranged on a turntable and a plurality of transmitting systems arranged at the periphery of the tested system, characterized in further comprising a radio frequency signal source and a power divider connected with the radio frequency signal source, the power divider is connected with the transmitting antennas of the transmitting systems through a plurality of optical fiber transmission networks.
2. The multipath analog test device of claim 1, wherein, Each of the optical fiber transmission networks comprises an E / O electric-optical converter, an adjustable optical fiber, an O / E optical-electric converter and a gain controller connected in sequence between the power divider and the transmitting antennas of the transmitting systems.
3. The multipath analog test device of claim 1, wherein, The power divider and the transmitting antennas of the transmitting systems are further provided with a vector network analyzer.
4. The multipath analog test device of claim 1, wherein, The distance between the erecting position of the transmitting antennas of the transmitting systems and the erecting position of the receiving antennas of the tested system is D, and the distance between the erecting position of the transmitting antennas of the transmitting systems and the edge of the standard open test field is d, wherein D≥10λ and d≥5λ, and λ refers to the wavelength of the lowest test frequency of the tested system.
5. The multipath analog test device of claim 4, wherein, The polarization mode and erecting height of the transmitting antennas of the transmitting systems and the receiving antennas of the receiving systems are consistent.
6. The multipath analog test device of claim 1, wherein, The center point of the receiving antennas of the tested system coincides with the center point of the turntable.