Beidou terminal performance closed-loop test system and method

Abstract

The invention belongs to the technical field of satellite navigation, and particularly relates to a Beidou terminal performance closed-loop test system and method, and the system comprises a multi-system GNSS navigation signal simulation source which is used for simulating a test signal and evaluating the core performance of a navigation terminal in real time; the Beidou RDSS and short message test system is used for simulating RDSS outbound signals and completing capturing, tracking, analysis and parameter measurement of RDSS inbound signals; the satellite navigation signal forwarding system is used for receiving satellite signals and completing work such as machine testing, system debugging, time service and positioning; the portable data acquisition and playback system is used for acquiring four signals, namely, a BDS signal, a GPS signal, a GLONASS signal and a Galileo signal; and the microwave anechoic chamber is used for providing a wireless shielding test environment, supporting the rotary table to spin and simulating the running state of the missile-borne receiver. According to the invention, the comprehensive testing of the basic function performance of various navigation products, such as passive positioning, active positioning, position report and short message, can be realized, and the method has a good market application prospect.

Description

Technical Field

[0001] The present invention belongs to the field of satellite navigation technology, and in particular relates to a Beidou terminal performance closed-loop testing system and method. Background Art

[0002] The BeiDou Navigation Satellite System, my country's independently developed global satellite navigation infrastructure, has evolved through the BeiDou-1, BeiDou-2, and BeiDou-3 systems to become a global, multi-frequency, and high-precision spatial information infrastructure. By 2023, the BeiDou system will serve users in over 200 countries and regions, achieving large-scale application in key areas such as transportation, emergency rescue, and smart agriculture. As BeiDou terminal devices evolve toward chip-based, modular, multi-mode, and multi-frequency designs, their performance testing and quality certification systems face new technical challenges.

[0003] In terms of technological evolution, the Beidou terminal testing system has undergone three phases of development. The initial phase (2012-2016) primarily referenced GPS terminal testing methods to establish a basic positioning performance testing framework. The mid-term phase (2017-2020) focused on developing specific testing standards for the B1C / B2a frequency bands, tailored to the new Beidou-3 signal system. The current phase (2021-present) addresses the testing complexity brought about by integrated technologies such as Beidou + 5G and Beidou + LEO augmentation. Currently, over 1.5 billion Beidou terminal devices are in use, encompassing over 20 product types, including automotive, shipborne, aircraftborne, and wearable devices. Traditional testing methods are unable to meet the rapid certification requirements for this massive volume of devices.

[0004] The existing testing system faces three major technical bottlenecks: First, the discretization of test items is prominent, and there is a lack of systematic cascaded testing solutions for 18 core indicators such as positioning accuracy, timing stability, and anti-interference capability. Second, the simulation accuracy of complex electromagnetic environments is insufficient. The existing darkroom test system can only reproduce less than 65% of typical scenarios such as urban canyons and ionospheric disturbances. Third, the testing efficiency does not match the speed of equipment iteration. Under the traditional stand-alone test mode, the full test of a single terminal takes more than 48 hours, which cannot adapt to the monthly development rhythm of intelligent connected terminals. According to statistics from the 2022 industry white paper, approximately 32% of the compatibility issues exposed by terminal devices in live network operation cannot be effectively detected in the laboratory stage.

[0005] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the Invention

[0006] The purpose of the present invention is to provide a Beidou terminal performance closed-loop test system and method to achieve comprehensive testing of the basic functional performance of various navigation products, including passive positioning, active positioning, position reporting and short message functions.

[0007] In order to achieve the above object, the present invention provides the following technical solutions: A BeiDou terminal performance closed-loop test system, comprising: Multi-system GNSS navigation signal simulation source, used to simulate test signals in typical scenarios, complex electromagnetic environments, and extreme dynamic scenarios, and to evaluate the core performance of navigation terminals in real time; BeiDou RDSS and short message test system is used to simulate RDSS outbound signals and complete the capture, tracking, analysis and parameter measurement of RDSS inbound signals, realizing closed-loop automated testing of the functional performance indicators of RDSS user terminals; Satellite navigation signal forwarding system, used to receive satellite signals and complete machine inspection, system debugging, timing and positioning work; Portable data acquisition and playback system for collecting BDS, GPS, GLONASS, and Galileo signals; The microwave darkroom is used to provide a wireless shielded test environment, support the turntable rotation, and simulate the operating status of the missile-borne receiver.

[0008] Preferably, the multi-system GNSS navigation signal simulation source supports custom configuration of parameters such as satellite constellation configuration, satellite clock error, device delay, and relativistic effect, accurately simulates the impact of the ionosphere and troposphere on navigation signals, and combines user dynamic characteristics modeling to construct a signal propagation environment.

[0009] Preferably, the multi-system GNSS navigation signal simulation source is equipped with an intelligent control and visual interaction system, which supports signal interruption / recovery, visible satellite signal switch, modulation mode switching and dynamic power adjustment, and displays satellite status, carrier operation trajectory, sub-satellite trajectory and visible satellite distribution information in real time through a graphical interface.

[0010] Preferably, the Beidou RDSS and short message test system adopts an integrated chassis design, which is compatible with external test system command interaction and realizes closed-loop automated testing; the Beidou RDSS and short message test system simulates 10 beam outbound signals of 5 GEO satellites, accurately constructs satellite orbit models, and synchronously receives and demodulates RDSS inbound signals, supporting two-way signal verification.

[0011] Preferably, the satellite navigation signal forwarding system covers the multi-band signals of GPS and Beidou satellites to closed areas where traditional signals are blocked, so that the equipment in the area can normally complete positioning, timing and system debugging tasks; the satellite navigation signal forwarding system efficiently captures weak signals through the receiving antenna, and after dynamic adjustment and enhancement by the core controller, it is forwarded by the transmitting antenna in a low-interference manner to form a complete signal optimization link.

[0012] Preferably, the portable data acquisition and playback system supports multi-band mixed processing of the four major navigation systems of Beidou, GPS, GLONASS and Galileo, and is equipped with a visual interface to display signal histograms, noise power, spectrum diagrams and satellite carrier-to-noise ratio positioning results in real time, and supports multi-machine cascade expansion to realize multi-band parallel acquisition.

[0013] Preferably, the microwave darkroom adopts a split design, with a metal conical cavity on the top and metal rectangular cavities in the middle and bottom; the metal conical cavity at the top of the microwave darkroom is affixed with microwave absorbing material, and is equipped with a circularly polarized antenna that integrates left-handed and right-handed polarization modes; the middle metal rectangular cavity of the microwave darkroom is affixed with microwave absorbing material, and is equipped with a miniaturized 3D test turntable driven by a high-power stepper motor; the metal rectangular cavity at the bottom of the microwave darkroom serves as a fixed space for input and output cables and the test turntable.

[0014] A BeiDou terminal performance closed-loop test method comprises the following steps: S1. Place the terminal under test on a 3D test turntable in a microwave anechoic chamber and start the turntable to simulate the motion or spin of the missile-borne receiver. The circularly polarized antenna in the microwave anechoic chamber is used to receive signals generated by a multi-system GNSS navigation signal simulation source / satellite navigation signal forwarding system / portable data acquisition and playback system, and simultaneously transmit dynamically adjusted navigation signals to the terminal under test. S2. Use the BeiDou RDSS and short message test system to simulate 10 outbound beam signals of 5 GEO satellites and accurately build satellite orbit models; S3. Configure test scenario parameters using a multi-system GNSS navigation signal simulation source. First, select the satellite system and signal frequency band, set the satellite clock error, ionosphere model, and carrier dynamic trajectory, add electromagnetic interference and signal power fluctuations, and perform wireless transmission using a circularly polarized antenna in a microwave anechoic chamber. Then, turn off the power of the 3D test turntable in the microwave anechoic chamber to perform a static test of the wireless performance of the terminal under test. S4. Install a portable data acquisition and playback system on an experimental vehicle and drive it in a typical scenario to collect BeiDou, GPS, GLONASS, and Galileo multi-band sky signals and environmental interference noise in real time. The collected data is then stored as standardized files and imported into the system for playback in a microwave anechoic chamber. S5: A satellite navigation signal forwarding system is deployed outdoors to capture the current real satellite signal. After filtering and amplification by the core controller, the signal is transmitted via a shielded cable to the circularly polarized antenna in the microwave anechoic chamber. The terminal under test receives the forwarded real signal in the microwave anechoic chamber, performs positioning / timing operations, and conducts wireless performance testing. S6. After executing S3, S4 and S5 respectively, the RDSS inbound signal generated by the terminal under test is captured and analyzed by the Beidou RDSS and short message test system, and the communication delay, bit error rate and power consistency indicators are automatically measured. The three test results are compared with the preset thresholds of the platform evaluation software to determine whether they meet the preset performance thresholds and generate a performance evaluation report.

[0015] As a preference, in S4, the collected data is stored as a standardized file and imported into the system. There are two ways to play it back in the microwave darkroom: Static playback: Fix the terminal under test on the turntable in the microwave anechoic chamber and play back the signal to verify the static environment performance; Dynamic playback: Start the turntable to simulate carrier movement and synchronously play back dynamic signals to test the terminal's adaptability to high-mobility scenarios.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) The Beidou terminal performance closed-loop test system and method of the present invention improves the absorbing performance of the darkroom and reduces the reflection of clutter signals by processing special microwave absorbing materials in the darkroom. In an environment where multi-mode clutter is not generated, the point source signal can be converted into a stable spherical wave signal through the right-handed circularly polarized antenna on the top of the darkroom.

[0017] (2) The Beidou terminal performance closed-loop test system and method of the present invention adopts a unique path loss calibration method. When testing the performance of Beidou terminal equipment, it effectively reduces the test deviation caused by system errors and achieves basic consistency with the measurement values of large-scale darkroom measurement systems.

[0018] (3) The Beidou terminal performance closed-loop test system and method of the present invention establishes models for various signal anomalies and distortions. Based on the signal anomaly model, a corresponding signal anomaly detection method at the receiving end is proposed, realizing a signal quality analysis with the ability to monitor the quality of satellite downlink navigation signals and detect abnormal signals for the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the composition of the Beidou terminal performance closed-loop test system of the present invention; Figure 2 This is the schematic diagram of the composition of the Beidou simulation signal source. DETAILED DESCRIPTION

[0020] The following is a clear and complete description of the technical solution of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts are within the scope of protection of the present invention.

[0021] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by terms such as "center", "up", "down", "left", "right", "vertical", "horizontal", "inside" and "outside" are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the invention.

[0022] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and connections within two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention.

[0023] Refer to the attached Figure 1-2 The present invention provides a Beidou terminal performance closed-loop test system, including a multi-system GNSS navigation signal simulation source, a Beidou RDSS and short message test system, a satellite navigation signal forwarding system, a portable data acquisition and playback system, and a microwave darkroom. The multi-system GNSS navigation signal simulation source is used to simulate test signals in typical scenarios, complex electromagnetic environments, and extreme dynamic scenarios, and to evaluate the core performance of navigation terminals such as positioning, speed measurement, and anti-interference in real time. The BeiDou RDSS and short message test system is used to simulate RDSS outbound signals and complete the capture, tracking, analysis and parameter measurement of RDSS inbound signals, thus realizing closed-loop automated testing of the functional performance indicators of RDSS user terminals. The satellite navigation signal forwarding system is used to receive satellite signals and complete tasks such as machine inspection, system debugging, timing, and positioning; The portable data acquisition and playback system is used to collect BDS, GPS, GLONASS, and Galileo signals; The microwave darkroom is used to provide a wireless shielded test environment, support the rotation of the turntable, and simulate the operating status of the missile-borne receiver.

[0024] In this embodiment, the multi-system GNSS navigation signal simulation source utilizes a standard 4U chassis with an integrated CPCI interface design. This supports flexible frequency upgrades via the CPCI motherboard interface card, offering high scalability. Equipped with over 18 independent channels, the multi-system GNSS navigation signal simulation source can simultaneously simulate multipath signals from four satellites, supporting highly complex scenario simulations.

[0025] The multi-system GNSS navigation signal simulation source has comprehensive simulation capabilities, supporting custom configuration of parameters such as satellite constellation configuration, satellite clock error, device delay, and relativistic effects. It can accurately simulate the impact of the ionosphere and troposphere on navigation signals, and at the same time combine user dynamic characteristic modeling to build a realistic signal propagation environment.

[0026] The multi-system GNSS navigation signal simulator also features an intelligent control and visual interaction system, supporting signal interruption / recovery, visible satellite signal switching, modulation mode switching, and dynamic power adjustment. A graphical interface displays key information in real time, including satellite status, carrier trajectory, sub-satellite trajectory, and visible satellite distribution. Designed specifically for satellite navigation product testing, this multi-system GNSS navigation signal simulator features carrier trajectory simulation and real-time data reception capabilities, enabling accurate evaluation of core performance indicators such as positioning, velocity, timing, sensitivity, and time to first fix. A multi-dimensional information panel dynamically displays visible satellite parameters, simulation time, satellite elevation / azimuth, Doppler shift, pseudorange, power, and carrier position / velocity.

[0027] The dynamic characteristics of the multi-system GNSS navigation signal simulation source support ultra-high-speed motion simulation of ±120,000m / s (accuracy 0.05m / s) and ±3,000m / s 2 High acceleration control (accuracy 0.05m / s 2 ), which can realistically reproduce extreme sports scenes. Signal generation accuracy reaches industry-leading levels, with a pseudorange control error of only 0.05m, channel delay consistency ≤0.1m, and initial signal phase consistency error ≤1°. Combined with a low phase noise floor exceeding -95dBc / Hz at 10kHz, and excellent suppression of ≤-40dBc clutter and ≤-35dBc harmonics, signal purity is ensured. Signal strength adjustment covers a wide dynamic range from -140dBm to -70dBm, supporting fine 0.2dB step adjustments. Overall control accuracy error does not exceed ±0.5dB, accurately simulating signal attenuation and interference characteristics in complex electromagnetic environments.

[0028] In this embodiment, the Beidou RDSS and short message test system adopts an integrated chassis design, is compatible with external test system command interaction, realizes closed-loop automated testing, can simulate 10 beam outbound signals of 5 GEO satellites, accurately construct satellite orbit models, and synchronously receive and demodulate RDSS inbound signals, supporting two-way signal verification.

[0029] BeiDou RDSS and short message test system has ultra-high speed (±12000m / s), high acceleration (±3000m / s 2 ) Dynamic scenario simulation capability, outbound signal pseudorange accuracy reaches ±0.05m, supports S-band ±4.08MHz bandwidth, wireless / wired output covers the range of -75dBm to -45dBm and -135dBm to -105dBm respectively, and power adjustment accuracy is ±0.5dB.

[0030] The BeiDou RDSS and short message test system uses Doppler simulation (±60kHz), 0.1ns time difference measurement and time synchronization technology to evaluate real-time performance indicators such as first capture, loss of lock and recapture, and verify the positioning success rate (error ≤1×10 -7 bit error rate) and high-frequency signal processing capability per second.

[0031] The Beidou RDSS and short message test system integrates functions such as coordinate conversion, broadcast control, and multi-frame communication fusion. It supports beam state identification and dynamic power management, can simulate complex scenarios such as overclocking and command shutdown, and comprehensively test the terminal's positioning and communication reliability in extreme dynamic environments. It is suitable for high-precision testing fields such as satellite navigation research and development and national defense equipment verification.

[0032] In this embodiment, the satellite navigation signal forwarding system can introduce GPS L1 / L2 / L5 and BD2 B1 / B2 / B3 signals into areas where satellite signals are blocked. GPS L1 / L2 / L5 and BD2 B1 / B2 / B3 receivers can be used in this area to receive GPS L1 / L2 / L5 and BD2 B1 / B2 / B3 satellite signals, enabling the equipment in the area to normally complete tasks such as machine inspection, system debugging, timing, and positioning.

[0033] The satellite navigation signal forwarding system fully supports GPS L1 / L2 / L5 and BeiDou-2 B1 / B2 / B3 multi-band signal processing, and the technical characteristics of the core components are highly coordinated. The receiving antenna has a high gain of 31±1dB and a low noise figure of ≤2.0dB, a standing wave ratio of ≤2.0, and an impedance matching of 50Ω, ensuring efficient capture of weak signals. The transmitting antenna adopts a right-hand circular polarization design, with a gain of 1±2dB, a transmit power of <-75dBm, and a standing wave ratio of ≤2.0, achieving low-interference and precise signal forwarding. The core controller integrates 10~40dB continuously adjustable gain (1dB step), and the standing wave ratio and noise figure are controlled at ≤2.0 and ≤2.0dB respectively. Combined with a standard 50Ω impedance, it forms a full-link optimization from signal reception, dynamic gain adjustment to transmit output, which can flexibly adapt to the needs of multi-band navigation signal enhancement and forwarding in complex electromagnetic environments.

[0034] In this embodiment, the portable data acquisition and playback system supports multi-band hybrid processing of the four major navigation systems: Beidou, GPS, GLONASS, and Galileo, and adopts a dual-band collaborative working mode. Band 1 can select B1 / L1 / G1 full-band or L-band inbound signals, while Band 2 supports flexible switching of B3 / L2 / G2, L5 / E5 / B2, or 2492MHz S-band outbound signals. This system can independently capture specific frequency bands or achieve simultaneous acquisition and playback of multiple bands. The portable data acquisition and playback system has a built-in 500GB solid-state drive (expandable to 2TB) and supports adjustable sampling bit widths of 2bit, 4bit, and 8bit. In dual-channel 2-bit mode, it can continuously record 166 minutes of data at a rate of 100MSPS, and can quickly import and export data via the network port.

[0035] The portable data acquisition and playback system, which accompanies the test vehicle, collects actual aerial signals under typical environmental conditions. After acquisition, the system replays the signals at the station to conduct dynamic testing of the terminal under test in real-world conditions, enabling repeatable indoor testing of the terminal's actual aerial performance. The portable data acquisition and playback system features an integrated 5-inch capacitive touchscreen and an intuitive visual interface, displaying real-time signal histograms, noise power, spectrum diagrams, and satellite carrier-to-noise ratio positioning results. It supports cascading expansion of multiple units for concurrent acquisition across multiple frequency bands.

[0036] The portable data acquisition and playback system's RF port features a wide dynamic input range of -80dBm to -30dBm and an output range of -75dBm to -25dBm. It also includes a built-in 0-60dB (1dB step) adjustable attenuator. The input port provides 5V / 200mA DC power, and the output uses a DC-blocking design to ensure signal purity. The time-frequency module supports 10MHz reference signal input and output, with phase noise as low as -110dBc / Hz at 10kHz, 1PPS pulse signal accuracy of 10μs ±1μs, and a synchronization interface compatible with the TTL-3.3V standard.

[0037] The portable data acquisition and playback system's expansion interface integrates CAN / I2C bus, RS232 serial port and GPIO control. The built-in battery has a battery life of 4 hours, supports a 12~20V wide-voltage power supply and 43W charging and discharging power. Through high-precision signal processing and multi-protocol compatible design, it can meet professional needs such as satellite navigation equipment research and development, signal characteristic analysis and complex scenario simulation, providing an integrated solution for RF signal acquisition, playback and real-time monitoring.

[0038] In this embodiment, after the microwave darkroom has passed the darkroom shielding, quiet zone, path loss and path delay tests, Figure 1 Connect the peripheral test equipment as shown, install the BeiDou simulation signal source (RDSS closed-loop test system) test software, input the path loss and path delay parameter values, and perform overall calibration and debugging. After debugging is completed, the entire microwave darkroom system can be put into use. Figure 2 As shown, the RF signal distribution unit outputs it as a signal.

[0039] The microwave anechoic chamber adopts a split design. The top section is a metal conical cavity test chamber lined with microwave absorbing material and equipped with a circularly polarized antenna with both left-hand and right-hand polarization modes. The circularly polarized antenna operates in the 1 GHz to 2.5 GHz frequency range. The center section of the microwave anechoic chamber is a metal rectangular cavity lined with microwave absorbing material and equipped with a miniaturized 3D test turntable driven by a high-power stepper motor. The maximum load capacity of the terminal under test on the turntable is ≤10 kg. The bottom section of the microwave anechoic chamber is a metal rectangular cavity with four lockable steering wheels, which provides a fixed space for input and output cables and the test turntable.

[0040] By treating the microwave anechoic chamber with specialized microwave absorbing materials, the chamber's absorption performance is enhanced and clutter signal reflections are reduced. A right-handed circularly polarized antenna mounted on the chamber's top can convert point-source signals into stable spherical wave signals without generating multimode clutter. To achieve this conversion, a dual-handed circularly polarized antenna was developed specifically for the test system. This antenna utilizes a composite structure of a conical and rectangular enclosure to ensure the purity of the spherical wave received by the test equipment and the stability of the test. A unique path loss calibration method effectively reduces test deviations caused by system errors during Beidou terminal device performance testing, ensuring nearly consistent measurements with those from large-scale anechoic chamber measurement systems. Furthermore, the system's self-calibration, combined with a Beidou simulated signal source (RDSS closed-loop test system), ensures the system's mass production suitability and consistent test data. The test system utilizes a unique structural design for far-field, single-azimuth scene measurement, enabling absolute value measurements in a compact space, comparable to large-scale anechoic chamber test systems. This approach offers low investment, high output, and significant budget savings.

[0041] The turntable utilizes a three-axis linkage mount structure: pitch, azimuth, and axial. Its power consumption is kept below 700W, combining high performance with low energy consumption. The turntable offers excellent motion precision, with positioning accuracy of ±1° in azimuth and ±1.5° in both pitch and axial. All axes exhibit zero cumulative error over long-term operation, ensuring stable and reliable positioning performance. The turntable can carry a maximum load of 10kg and 8kg in axial and angular directions, making it suitable for a wide range of equipment. Speeds range from 1-10° / s in azimuth and 1-5° / s in pitch and axial directions, with speed errors of no more than ±1° / s in each axis. The turntable's full rotation range includes continuous 0-360° rotation in azimuth, wide pitch angles from -90° to +90° in pitch, and unlimited ±360° axial rotation (protected by electrical limit switches), fully meeting the needs of spatial pointing in various scenarios. The entire unit weighs just 25kg and is equipped with an intelligent zero-position search function, enabling rapid calibration and precise resetting. With its high precision, strong load capacity, and wide-range motion characteristics, the turntable is particularly suitable for precision control applications such as photoelectric tracking, instrument calibration, and automated testing.

[0042] On the other hand, the present invention also provides a Beidou terminal performance closed-loop testing method, comprising the following steps: Step 1: Place the terminal under test on a 3D test turntable in a microwave anechoic chamber and start the turntable to simulate the motion or rotation of the missile-borne receiver. The circularly polarized antenna in the microwave anechoic chamber is used to receive signals generated by the multi-system GNSS navigation signal simulation source / satellite navigation signal forwarding system / portable data acquisition and playback system, and simultaneously transmit dynamically adjusted navigation signals to the terminal under test. Step 2: Use the BeiDou RDSS and short message test system to simulate 10 outbound beam signals from five GEO satellites and accurately construct satellite orbit models. Step 3: Configure the test scenario parameters using a multi-system GNSS navigation signal simulation source. First, select the satellite system (BD2 / GPS / GLONASS) and signal frequency band. Then, set the satellite clock error, ionospheric model, and carrier dynamic trajectory. Add abnormal conditions such as electromagnetic interference and signal power fluctuations. Perform wireless transmission using a circularly polarized antenna within the microwave anechoic chamber. Then, turn off the power of the 3D test turntable within the microwave anechoic chamber to perform a static test of the wireless performance of the terminal under test. Step 4: Mount the portable data acquisition and playback system on the experimental vehicle and drive it through typical scenarios (urban canyons, mountainous areas, and highways). The system collects BeiDou, GPS, GLONASS, and Galileo multi-band sky signals and environmental interference noise (such as base station radiation and multipath effects) in real time. The collected data is then stored as standardized files and imported into the system for playback in a microwave anechoic chamber using the following two methods: ① Static playback: Fix the terminal under test on the turntable of the microwave anechoic chamber and play back the signal to verify the static environment performance; ② Dynamic playback: Start the turntable to simulate carrier motion (such as rotation and tilt), synchronously play back dynamic signals, and test the adaptability of the terminal under test to high-mobility scenarios; Step 5: Deploy a satellite navigation signal forwarding system outdoors to capture the current real satellite signal (BDS / GPS, etc.). After filtering and amplification by the core controller, the signal is transmitted via a shielded cable to the circularly polarized antenna in the microwave anechoic chamber. The terminal under test receives the forwarded real signal in the microwave anechoic chamber, performs positioning / timing operations, and conducts wireless performance tests. Step 6: After executing steps 3, 4, and 5 respectively, the RDSS inbound signal generated by the terminal under test is captured and analyzed by the Beidou RDSS and short message test system. The communication delay, bit error rate, power consistency and other indicators are automatically measured. The three test results are compared with the preset thresholds of the platform evaluation software to determine whether they meet the preset performance thresholds and generate a performance evaluation report.

[0043] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A BeiDou terminal performance closed-loop test system, characterized in that: include: Multi-system GNSS navigation signal simulation source, used to simulate test signals in typical scenarios, complex electromagnetic environments, and extreme dynamic scenarios, and to evaluate the core performance of navigation terminals in real time; BeiDou RDSS and short message test system is used to simulate RDSS outbound signals and complete the capture, tracking, analysis and parameter measurement of RDSS inbound signals, realizing closed-loop automated testing of the functional performance indicators of RDSS user terminals; Satellite navigation signal forwarding system, used to receive satellite signals and complete machine inspection, system debugging, timing and positioning work; Portable data acquisition and playback system for collecting BDS, GPS, GLONASS, and Galileo signals; The microwave darkroom is used to provide a wireless shielded test environment, support the turntable rotation, and simulate the operating status of the missile-borne receiver.

2. The BeiDou terminal performance closed-loop test system according to claim 1, characterized in that: The multi-system GNSS navigation signal simulation source supports custom configuration of parameters such as satellite constellation configuration, satellite clock error, device delay, and relativistic effect, accurately simulates the impact of the ionosphere and troposphere on navigation signals, and combines user dynamic characteristics modeling to construct a signal propagation environment.

3. The BeiDou terminal performance closed-loop test system according to claim 1, characterized in that: The multi-system GNSS navigation signal simulation source is equipped with an intelligent control and visual interaction system, which supports signal interruption / recovery, visible satellite signal switching, modulation mode switching and dynamic power adjustment, and displays satellite status, carrier operation trajectory, sub-satellite trajectory and visible satellite distribution information in real time through a graphical interface.

4. The BeiDou terminal performance closed-loop test system according to claim 1, characterized in that: The Beidou RDSS and short message test system adopts an integrated chassis design, is compatible with external test system command interaction, and realizes closed-loop automated testing; the Beidou RDSS and short message test system simulates 10 beam outbound signals of 5 GEO satellites, accurately constructs satellite orbit models, and synchronously receives and demodulates RDSS inbound signals, supporting two-way signal verification.

5. The BeiDou terminal performance closed-loop test system according to claim 1, characterized in that: The satellite navigation signal forwarding system covers the multi-band signals of GPS and Beidou satellites to closed areas where traditional signals are blocked, so that the equipment in the area can normally complete positioning, timing and system debugging tasks; the satellite navigation signal forwarding system efficiently captures weak signals through the receiving antenna, and after dynamic adjustment and enhancement by the core controller, it is forwarded by the transmitting antenna in a low-interference manner, forming a complete signal optimization link.

6. The BeiDou terminal performance closed-loop test system according to claim 1, characterized in that: The portable data acquisition and playback system supports multi-band mixed processing of the four major navigation systems: Beidou, GPS, GLONASS, and Galileo. It is equipped with a visual interface to display signal histograms, noise power, spectrum diagrams, and satellite carrier-to-noise ratio positioning results in real time, and supports multi-machine cascade expansion to achieve multi-band parallel acquisition.

7. The BeiDou terminal performance closed-loop test system according to claim 1, characterized in that: The microwave anechoic chamber adopts a split design, with a metal conical cavity on the top and metal rectangular cavities in the middle and bottom. The metal conical cavity at the top of the microwave anechoic chamber is affixed with microwave absorbing material and is equipped with a circularly polarized antenna that integrates left-handed and right-handed polarization modes. The metal rectangular cavity in the middle of the microwave anechoic chamber is also affixed with microwave absorbing material and is equipped with a miniaturized 3D test turntable driven by a high-power stepping motor. The metal rectangular cavity at the bottom of the microwave anechoic chamber serves as a fixed space for input and output cables and the test turntable.

8. A BeiDou terminal performance closed-loop test method, characterized in that: The following steps are involved: S1. Place the terminal under test on a 3D test turntable in a microwave anechoic chamber and start the turntable to simulate the motion or spin of the missile-borne receiver. The circularly polarized antenna in the microwave anechoic chamber is used to receive signals generated by a multi-system GNSS navigation signal simulation source / satellite navigation signal forwarding system / portable data acquisition and playback system, and simultaneously transmit dynamically adjusted navigation signals to the terminal under test. S2. Use the BeiDou RDSS and short message test system to simulate 10 outbound beam signals of 5 GEO satellites and accurately build satellite orbit models; S3. Configure test scenario parameters using a multi-system GNSS navigation signal simulation source. First, select the satellite system and signal frequency band, set the satellite clock error, ionosphere model, and carrier dynamic trajectory, add electromagnetic interference and signal power fluctuations, and perform wireless transmission using a circularly polarized antenna in a microwave anechoic chamber. Then, turn off the power of the 3D test turntable in the microwave anechoic chamber to perform a static test of the wireless performance of the terminal under test. S4. Install a portable data acquisition and playback system on an experimental vehicle and drive it in a typical scenario to collect BeiDou, GPS, GLONASS, and Galileo multi-band sky signals and environmental interference noise in real time. The collected data is then stored as standardized files and imported into the system for playback in a microwave anechoic chamber. S5: A satellite navigation signal forwarding system is deployed outdoors to capture the current real satellite signal. After filtering and amplification by the core controller, the signal is transmitted via a shielded cable to the circularly polarized antenna in the microwave anechoic chamber. The terminal under test receives the forwarded real signal in the microwave anechoic chamber, performs positioning / timing operations, and conducts wireless performance testing. S6. After executing S3, S4 and S5 respectively, the RDSS inbound signal generated by the terminal under test is captured and analyzed by the Beidou RDSS and short message test system, and the communication delay, bit error rate and power consistency indicators are automatically measured. The three test results are compared with the preset thresholds of the platform evaluation software to determine whether they meet the preset performance thresholds and generate a performance evaluation report.

9. The BeiDou terminal performance closed-loop test system according to claim 8, characterized in that: In S4, the collected data is stored as a standardized file and imported into the system. There are two ways to play it back in the microwave darkroom: Static playback: Fix the terminal under test on the turntable in the microwave anechoic chamber and play back the signal to verify the static environment performance; Dynamic playback: Start the turntable to simulate carrier movement and synchronously play back dynamic signals to test the terminal's adaptability to high-mobility scenarios.

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