Satellite navigation time service precision detection system and method

Abstract

This application provides a satellite navigation timing accuracy testing system and method, relating to the field of satellite navigation testing technology. The system includes an electromagnetic shielding test space; a through-wall assembly installed on the shielding wall to enable internal and external signal transmission; a satellite navigation signal simulation module that radiates satellite navigation signals to the device under test (DUT); an interference signal injection module that injects interference signals and calibrates the interference power based on a power detection component; a time deviation measurement module that receives frequency and time reference signals from an external timing reference device and measures the time deviation of the DUT; and a data acquisition and judgment module that simultaneously acquires time deviation and RF status data under different interference powers and constructs a mapping relationship to output the judgment result. This application reuses an external reference to simplify the architecture, establishes a quantitative mapping between interference intensity and timing accuracy, and improves the reproducibility and quantitative evaluation capabilities of the testing.

Description

Technical Field

[0001] This application relates to the field of satellite navigation detection technology, specifically to a satellite navigation timing accuracy detection system and method. Background Technology

[0002] Currently, in the field of satellite navigation timing accuracy testing, existing testing systems typically rely on expensive internal independent time and frequency reference sources as measurement references, resulting in complex system hardware architectures and high construction and maintenance costs. Furthermore, existing testing methods often separate timing accuracy testing and anti-interference testing into different devices or environments, lacking a mechanism to correlate interference signal strength with timing deviation under controlled electromagnetic conditions. This makes it difficult to establish a quantitative mapping relationship between interference power and timing accuracy, resulting in a lack of reproducible quantitative evidence for assessing the anti-interference capability of the device under test. Therefore, there is an urgent need for a satellite navigation timing accuracy testing system and method that can simplify the system architecture and achieve quantitative mapping detection of interference strength and timing accuracy. Summary of the Invention

[0003] To address the problems of existing technologies, such as complex and costly detection system architecture and lack of quantitative mapping relationship between interference intensity and timing accuracy, which leads to a lack of reproducible quantitative basis for evaluating the anti-interference capability of the device under test, this application realizes high-precision measurement by reusing external time and frequency reference in an electromagnetic shielding environment through a satellite navigation timing accuracy detection system and method, and constructs a quantitative mapping model between interference power and timing deviation.

[0004] To achieve the above objectives, this application adopts the following technical solution: A satellite navigation timing accuracy testing system includes an electromagnetic shielding test space, a through-wall assembly, a satellite navigation signal simulation module, an interference signal injection module, a time deviation measurement module, and a data acquisition and judgment module. The through-wall assembly is mounted on the shielding wall of the electromagnetic shielding test space to enable signal transmission inside and outside the test space while maintaining electromagnetic shielding effectiveness. The satellite navigation signal simulation module is configured to radiate satellite navigation signals to the device under test (DUT) within the electromagnetic shielding test space. The interference signal injection module is configured to inject interference signals into the DUT and calibrate the interference power of the interference signal at the antenna position of the DUT based on a power detection component. The time deviation measurement module is configured to receive frequency reference signals and time reference signals output from an external timing reference device and measure the time deviation of the time signal output by the DUT relative to the time reference signal. The data acquisition and judgment module is configured to simultaneously acquire time deviations under different interference powers and RF status data output by the DUT based on the satellite navigation signal, and construct a mapping relationship based on the time deviation and interference power to output a timing accuracy judgment result.

[0005] Preferably, the external reference input terminal of the time deviation measurement module is connected to the frequency reference output terminal of the external time reference device to receive the frequency reference signal; the open channel of the time deviation measurement module is connected to the time reference output terminal of the external time reference device to receive the time reference signal; and the closed channel of the time deviation measurement module is connected to the time signal output terminal of the device under test to receive the time signal.

[0006] Preferably, the frequency reference signal is a high-frequency reference signal, and the time reference signal is a second pulse time reference signal; the time deviation measurement module uses the high-frequency reference signal as the clock reference to measure the time difference between the second pulse time reference signal received by the door opening channel and the time signal received by the door closing channel to obtain the time deviation.

[0007] Preferably, the interference signal injection module includes a radio frequency (RF) signal generator, a power amplifier, an adjustable attenuator, a directional coupler, and a power detection component. The output of the RF signal generator is connected to the input of the power amplifier, and the output of the power amplifier is connected in series with the directional coupler and then connected to the transmitting antenna. The adjustable attenuator is positioned in the path between the RF signal generator and the power amplifier, or in the path between the power amplifier and the directional coupler. The power detection component includes a power meter, and the coupling end of the directional coupler is connected to the power meter to calibrate the interference power at the antenna location of the device under test.

[0008] Preferably, the radio frequency signal generator is configured to generate in-band and out-of-band interference signals as interference signals; the adjustable attenuator is configured to adjust the interference power in preset steps; and the data acquisition and judgment module establishes a power control lookup table based on the feedback data of the power meter to control the interference power.

[0009] Preferably, the radio frequency status data includes the number of visible satellites and the carrier-to-noise ratio; the data acquisition and judgment module is configured to simultaneously acquire the time deviation, the number of visible satellites and the carrier-to-noise ratio under different interference powers, and generate an anti-interference tolerance curve based on the time deviation and interference power. The anti-interference tolerance curve characterizes the mapping relationship between interference power and time deviation.

[0010] Preferably, the interference signals include in-band interference signals and out-of-band interference signals; the data acquisition and judgment module is configured as follows: based on the anti-interference tolerance curve, when the interference power of the out-of-band interference signal reaches the first preset threshold, the timing synchronization status of the device under test is determined; when the interference power of the in-band interference signal reaches the second preset threshold, the timing accuracy status of the device under test is determined; when the interference power reaches the third preset threshold, the device under test is verified to output an interference detection flag.

[0011] Preferably, the through-wall assembly includes an RF through-wall board, a serial port through-wall board, and a time-frequency signal through-wall board; the RF through-wall board is used to transmit satellite navigation signals and interference signals; the serial port through-wall board is used to transmit serial port data of the device under test; the time-frequency signal through-wall board is used to transmit time signals; the inner walls and test platform of the electromagnetic shielding test space are covered with absorbing material.

[0012] Furthermore, this application also provides a satellite navigation timing accuracy detection method, applied to the satellite navigation timing accuracy detection system described above, comprising: preheating the system in an electromagnetic shielding test space, and calibrating the interference power of the interference signal at the antenna position of the device under test based on the power detection component; measuring the baseline time deviation of the time signal output by the device under test relative to the time reference signal based on the frequency reference signal and time reference signal output by an external timing reference device in a state without interference signal injection; injecting interference signals into the device under test in a preset step, and simultaneously collecting time deviation and radio frequency status data under different interference powers; constructing a mapping relationship based on the collected time deviation and interference power, and outputting the timing accuracy judgment result based on the mapping relationship and radio frequency status data.

[0013] The above method ensures the consistency of environmental conditions and reference sources across different test batches through standardized testing procedures. Combined with spatial power calibration and multi-dimensional data synchronous acquisition mechanisms, it achieves automated generation and traceability of timing accuracy test results.

[0014] Preferably, interference signals are injected into the device under test (DUT) at preset steps, and time deviations and radio frequency (RF) status data are collected simultaneously at different interference power levels. This includes: performing sensitivity testing by reducing the power of the satellite navigation signal at preset power reduction steps and recording the acquisition and tracking sensitivity of the DUT; and performing anti-interference testing by increasing the interference power at preset power increase steps, maintaining each power level for a preset time, and recording the time deviation, number of visible satellites, and carrier-to-noise ratio (CNR) corresponding to each power level. A mapping relationship is constructed based on the collected time deviations and interference power, including generating an anti-interference tolerance curve based on the time deviations corresponding to each power level recorded in the anti-interference test.

[0015] Beneficial effects: This application constructs an integrated testing architecture within an electromagnetic shielding test space. On one hand, it utilizes a through-wall panel assembly and a specific interface topology to reuse the frequency and time references provided by an external timing reference device, replacing the expensive internal independent high-precision clock source in traditional testing systems. This significantly reduces system hardware complexity and construction costs while ensuring the traceability and accuracy of the measurement reference. On the other hand, the power detection component in the interference signal injection module performs precise spatial calibration of the interference power at the antenna position of the device under test. The data acquisition and judgment module simultaneously collects the time deviation and RF status data under this calibrated power, thereby establishing a quantitative mapping relationship between interference intensity and timing accuracy. This overcomes the shortcomings of existing technologies where interference testing and accuracy testing are separated, and anti-interference capabilities cannot be quantitatively evaluated, thus improving the reproducibility and engineering practical value of the test results.

[0016] This application simplifies the system architecture not only by clearly defining the physical interface connection between the time deviation measurement module and the external timing reference device and the device under test, that is, by receiving the frequency reference, time reference and the time signal under test through the external reference input terminal, the open channel and the closed channel respectively. This simplifies the system architecture not only at the software logic level, but also by substantially improving the hardware connection. This specific signal flow path ensures the integrity and stability of the measurement link when reusing the external reference, and also facilitates the quick verification of the system configuration compliance by checking the physical wiring in practical applications.

[0017] This application employs a directional coupler connected in series with the power amplifier output path in the interference signal injection module, and connects its coupling end to a specific hardware topology of the power meter. Combined with the step adjustment of the adjustable attenuator and the establishment of a power control lookup table, it achieves closed-loop precise control and real-time calibration of the interference power at the antenna position of the device under test. This eliminates the influence of cable loss, connector differences, and spatial propagation uncertainties on the interference intensity calibration, and provides a reliable physical basis for constructing a high-precision anti-interference tolerance curve.

[0018] The data acquisition and judgment module of this application synchronously collects multi-dimensional radio frequency status data such as time deviation, number of visible satellites, and carrier-to-noise ratio. Based on these data, it generates an anti-interference tolerance curve that characterizes the mapping relationship between interference power and time deviation. Then, it automatically judges the time synchronization status, timekeeping accuracy status, and interference detection flag based on preset thresholds. This realizes the transformation from single-index testing to multi-dimensional comprehensive performance evaluation, so that the test results can fully reflect the actual time synchronization performance of the device under test in complex electromagnetic environment, improving the testing efficiency and the objectivity of the judgment. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall architecture of the satellite navigation timing accuracy detection system according to an embodiment of this application; Figure 2 This is a schematic diagram of the interference power versus timing deviation mapping curve in an embodiment of this application; Figure 3 This is a flowchart of a satellite navigation timing accuracy detection method according to an embodiment of this application.

[0020] Among them, 100-electromagnetic shielding test space, 110-through wall panel assembly, 200-satellite navigation signal simulation module, 210-transmitting antenna, 300-interference signal injection module, 400-time deviation measurement module, 500-data acquisition and judgment module, 600-external time reference device, and 700-device under test. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0023] Example 1: As Figure 1 As shown, this embodiment provides a satellite navigation timing accuracy testing system. The system mainly includes an electromagnetic shielding test space 100, a through-wall panel assembly 110, a satellite navigation signal simulation module 200, an interference signal injection module 300, a time deviation measurement module 400, and a data acquisition and judgment module 500.

[0024] The electromagnetic shielding test space 100 provides a pure testing environment that isolates external electromagnetic interference, serving as the physical basis for high-precision quantitative timing detection. Specifically, the inner walls and test platform of the electromagnetic shielding test space 100 are lined with absorbing materials, such as polyurethane foam or conical absorbing sponges, to absorb electromagnetic wave reflections within the space and suppress the influence of multipath effects on the received signals of the device under test 700, thereby ensuring the controllability and reproducibility of the test conditions. Simultaneously, a through-wall assembly 110 is installed on the shielding wall of the electromagnetic shielding test space 100. This through-wall assembly 110 enables signal transmission inside and outside the electromagnetic shielding test space 100 while maintaining electromagnetic shielding effectiveness. In this embodiment, the through-wall assembly 110 is not a single through-hole structure but is functionally partitioned according to signal type, specifically including an RF through-wall assembly, a serial port through-wall assembly, and a time-frequency signal through-wall assembly. The RF through-wall board is used to transmit satellite navigation signals and interference signals, ensuring impedance matching and shielding continuity of the RF link; the serial port through-wall board is used to transmit serial port data from the device under test (DUT) 700, and typically employs opto-isolation design to cut off ground loop interference; the time-frequency signal through-wall board is specifically used to transmit high-precision time signals, ensuring the signal integrity of the time-frequency reference when passing through the shielding wall. This classified transmission design effectively avoids crosstalk between different types of signals, ensuring the accuracy of test data.

[0025] The satellite navigation signal simulation module 200 is configured to radiate satellite navigation signals to the device under test 700 within the electromagnetic shielding test space 100. Specifically, the satellite navigation signal simulation module 200 is connected to the transmitting antenna 210 located inside the electromagnetic shielding test space 100 via an RF through-wall plate, radiating standard and controllable satellite navigation signals to the device under test 700. This provides a stable timing source for the device under test 700, replacing the uncontrollable real satellite signals, thus eliminating the influence of external environmental factors such as weather and geographical location on the test results.

[0026] The interference signal injection module 300 is configured to inject an interference signal into the device under test (DUT) 700 and calibrate the interference power of the interference signal at the antenna position of the DUT 700 based on the power detection component. This feature highlights the fundamental difference between the system in this application and conventional instruments that are simply pieced together. Specifically, the interference signal injection module 300 not only generates an interference signal, but more importantly, it achieves accurate calibration of the actual interference power received at the antenna aperture of the DUT 700 through the integrated power detection component. This spatial calibration mechanism eliminates errors caused by cable loss, connector differences, and uncertainties in spatial propagation paths, providing a reliable physical quantity reference for subsequently establishing accurate mapping relationships.

[0027] The time deviation measurement module 400 is configured to receive the frequency reference signal and time reference signal output by the external time reference device 600, and measure the time deviation of the time signal output by the device under test 700 relative to the time reference signal based on the frequency reference signal and time reference signal. In this embodiment, the system does not have an expensive high-precision atomic clock built in as an independent reference, but instead reuses the existing external time reference device 600 through a specific interface topology. Specifically, the time deviation measurement module 400 obtains the frequency reference and time reference provided by the external time reference device 600 through a time and frequency signal through-wall plate, respectively, and uses them as reference scales for measurement. This external reference reuse architecture significantly simplifies the internal hardware topology of the system and reduces construction and maintenance costs while ensuring measurement traceability and accuracy.

[0028] The data acquisition and judgment module 500 is configured to simultaneously acquire time deviations under different interference powers and RF status data output by the device under test 700 based on satellite navigation signals. It then constructs a mapping relationship between time deviation and interference power to output a timing accuracy judgment result. Specifically, the data acquisition and judgment module 500, as the system's central component, reads the deviation data output by the time deviation measurement module 400 in real time, and simultaneously acquires the interference power value calibrated by the interference signal injection module 300, as well as RF status data such as the number of visible satellites and carrier-to-noise ratio fed back by the device under test 700. By rigorously aligning and correlating these multi-dimensional data along the time axis, the data acquisition and judgment module 500 can construct a mapping model characterizing the quantitative relationship between interference intensity and timing performance. Based on preset rules, it automatically outputs objective and quantifiable judgment results, solving the technical problem of separating interference testing and accuracy testing in existing technologies, which prevents a comprehensive evaluation of anti-interference capabilities.

[0029] It should be understood that, although Figure 1 This paper demonstrates a specific layout of the modules. However, in other embodiments, the physical location of each module can be adjusted according to the actual site conditions. For example, the data acquisition and judgment module 500 can be placed outside the electromagnetic shielding test space 100 and interact with the data through the wall-penetrating plate assembly 110. Alternatively, some functions can be integrated into the same hardware carrier. As long as the above-mentioned functional connection and data flow logic can be realized, they all fall within the protection scope of this application.

[0030] The physical interface connections between the time deviation measurement module 400, the external timing reference device 600, and the device under test (DUT) 700 are described in detail below. The external reference input of the time deviation measurement module 400 is connected to the frequency reference output of the external timing reference device 600 to receive the frequency reference signal. Specifically, this external reference input typically corresponds to the REF IN interface on the instrument's backplane and is connected to the frequency output port of the external timing reference device 600 via a low-loss coaxial cable. This direct hardware connection allows the local oscillator inside the time deviation measurement module 400 to be locked to a more stable external frequency source or used directly as an external clock reference. This ensures that the time base accuracy of the entire measurement system is directly traceable to the external timing reference device 600, rather than relying on a low-cost crystal oscillator that may exist within the detection system itself, thus guaranteeing the authority and accuracy of the measurement results from a physical link perspective.

[0031] The start channel of the time deviation measurement module 400 is connected to the time reference output terminal of the external time reference device 600 to receive the time reference signal. Simultaneously, the stop channel of the time deviation measurement module 400 is connected to the time signal output terminal of the device under test (DUT) 700 to receive the time signal output by the DUT 700. Specifically, the start channel (Start) receives the time reference representing the standard true value, while the stop channel (Stop) receives the time signal representing the actual measured value. During the measurement process, the time deviation measurement module 400 uses the externally injected frequency reference signal as a high-resolution counting clock to accurately measure the time interval from the rising edge of the start channel to the rising edge of the stop channel. This time interval is the time deviation of the DUT 700 relative to the external time reference device 600. This Start-Stop measurement mechanism based on an external unified time base effectively eliminates systematic errors caused by the asynchronous clocks of the measuring instrument and the DUT, ensuring that the measurement results accurately reflect the timekeeping performance of the DUT 700.

[0032] Regarding the specific signal format, the frequency reference signal can be a high-frequency reference signal, and the time reference signal can be a second pulse time reference signal. For example, in a preferred embodiment, the high-frequency reference signal is a 10MHz sine wave signal, and the second pulse time reference signal is a 1PPS (Pulse Per Second) pulse signal. It should be understood that this is only one specific implementation of this application and is not a limitation on the scope of protection. In other embodiments, the frequency reference signal can also be a 5MHz, 100MHz, or other frequency sine wave or square wave signal; the time reference signal can also be an IRIG-B code, a PTP (Precision Time Protocol) message, or other coded signal containing precise timestamp information. As long as the signal can provide a stable frequency reference and a clear time synchronization mark, it can be applied to the detection system of this application.

[0033] Through the specific interface topology and signal coordination described above, this embodiment achieves deep reuse of the external time reference device 600. On the one hand, the high-stability frequency characteristics of the external time reference device 600 replace the expensive independent atomic clock or temperature-controlled crystal oscillator inside the detection system, significantly reducing hardware costs and maintenance complexity. On the other hand, by directly introducing the external time reference into the access channel of the measurement module, a complete traceability link from the reference source to the measurement terminal is constructed, ensuring that the time accuracy test results are comparable and legally valid under different test batches and different test locations, thus solving the data dispersion problem caused by the lack of a unified reference in traditional distributed testing.

[0034] The internal hardware links and power calibration control mechanism of the interference signal injection module 300 are described in detail below. The interference signal injection module 300 includes a radio frequency (RF) signal generator, a power amplifier, an adjustable attenuator, a directional coupler, and a power detection component. Specifically, the output of the RF signal generator is connected to the input of the power amplifier to generate and amplify the initial interference signal; the output of the power amplifier is connected in series with the directional coupler and then to the transmitting antenna 210, radiating the interference signal to the device under test (DUT) 700 within the electromagnetic shielding test space 100. The adjustable attenuator is located in the path between the RF signal generator and the power amplifier, or in the path between the power amplifier and the directional coupler, to finely adjust the signal strength in the link. The power detection component includes a power meter; the coupling end of the directional coupler is connected to the power meter to calibrate the interference power at the antenna position of the DUT 700.

[0035] The core of the above hardware topology design lies in the specific cascade position of the directional coupler. In conventional RF test systems, the power monitoring point is often set at the signal source output or power amplifier input. This method cannot reflect the actual radiated power after the signal has undergone nonlinear amplification by the power amplifier, cable transmission loss, and connector impedance mismatch, resulting in significant uncertainty in the true interference intensity at the antenna aperture of the device under test. In this application, by directly cascading the directional coupler between the output of the power amplifier and the transmitting antenna 210, and connecting the coupling end to the power meter, the power detection component can acquire the actual output power value after passing through the complete RF link in real time. This end-sampling mechanism effectively eliminates system errors introduced by factors such as power amplifier gain fluctuations, cable attenuation changes, and connector contact resistance, ensuring that the calibrated interference power truly corresponds to the spatial field strength at the antenna position of the device under test (700), providing a reliable physical quantity benchmark for subsequently constructing a high-precision interference-precision mapping relationship.

[0036] Furthermore, the radio frequency signal generator is configured to generate in-band and out-of-band interference signals as interference signals. For example, in a preferred embodiment, the in-band interference signal may be a continuous wave or modulated signal with a center frequency of 1561.098 MHz, and the out-of-band interference signal may be noise or single-tone signals in the 1447 MHz-1467 MHz or 1785 MHz-1805 MHz frequency band. However, it should be understood that these specific frequency bands are merely exemplary choices adapted to a particular satellite navigation system and are not intended to limit the scope of protection of this application. In other embodiments, the frequency band of the interference signal can be flexibly configured according to the satellite navigation system supported by the device under test 700, as long as it can cover the operating frequency band of the device under test and its adjacent frequency bands.

[0037] To achieve precise controllability of interference power, the adjustable attenuator is configured to adjust the interference power in preset steps. The data acquisition and judgment module 500 establishes a power control lookup table based on the feedback data from the power meter to control the interference power. Specifically, during system initialization or each test configuration change, the data acquisition and judgment module 500 drives the adjustable attenuator to traverse the entire attenuation range in preset steps, and synchronously reads the actual power value fed back by the power meter at each step point. Due to the nonlinearity or temperature drift of the device characteristics in the RF link, the preset attenuation value and the actual output power are often not ideally linearly related. Through the above scanning process, the data acquisition and judgment module 500 can establish a power control lookup table containing a triplet of target power, attenuator setpoint, and measured power. During formal testing, when an interference signal of a specific strength needs to be injected, the system no longer relies on theoretical calculations or open-loop settings, but directly queries the lookup table to obtain the corresponding attenuator setpoint and makes fine adjustments based on the real-time feedback from the power meter. This closed-loop calibration mechanism based on measured data overcomes the power deviation problem caused by device aging, temperature changes or batch differences in traditional open-loop control, ensuring the accuracy and stability of interference power calibration throughout the entire test cycle, thereby supporting the confidence of quantitative evaluation results such as anti-interference tolerance curves.

[0038] It should be understood that although this embodiment describes a preferred topology where a directional coupler is connected in series at the output of the power amplifier, in other embodiments, if the power amplifier integrates a built-in coupling port and its coupling accuracy meets the calibration requirements, the built-in port can also be used to replace the external directional coupler. As long as accurate monitoring and feedback of the interference power at the antenna position of the device under test can be achieved, it falls within the protection scope of this application. Similarly, the method of establishing the power control lookup table is not limited to the above-described point-by-point scanning method. Piecewise fitting, polynomial modeling, or machine learning prediction methods can also be used. As long as the mapping relationship between the attenuator setpoint and the actual output power can be characterized and used for closed-loop control, it can be applied to the detection system of this application.

[0039] The following is combined Figure 2The process of constructing multi-dimensional data mapping relationships and executing judgment logic in the data acquisition and judgment module 500 is described in detail. RF status data includes the number of visible satellites and the carrier-to-noise ratio (CNR). Specifically, during testing, the data acquisition and judgment module 500 does not simply record a single time deviation indicator, but instead reads the NMEA statements or other custom protocol data output by the device under test (DUT) 700 in real time through a serial port through-wall board, extracting key RF status parameters such as the number of visible satellites and the CNR. Simultaneously, the data acquisition and judgment module 500 also acquires the high-precision time deviation value output by the time deviation measurement module 400 and the spatially calibrated interference power value fed back by the interference signal injection module 300. This synchronous acquisition mechanism of multi-dimensional data is crucial because when the DUT 700 is subjected to interference, the degradation of its timing accuracy is often accompanied by a decrease in the number of visible satellites or a drop in the CNR. It is difficult to distinguish whether the performance degradation is caused by signal obstruction, multipath effects, or human interference based solely on the time deviation indicator. By strictly aligning the time deviation with the number of visible satellites and the carrier-to-noise ratio on the time axis, the data acquisition and judgment module 500 can comprehensively characterize the integrated response characteristics of the device under test 700 in a complex electromagnetic environment, providing sufficient data support for subsequent accurate judgment.

[0040] The data acquisition and judgment module 500 is configured to simultaneously acquire time deviation, number of visible satellites, and carrier-to-noise ratio under different interference powers, and generate an anti-interference tolerance curve based on the time deviation and interference power. The anti-interference tolerance curve characterizes the mapping relationship between interference power and time deviation. Specifically, such as... Figure 2 As shown, the anti-interference tolerance curve is a two-dimensional quantitative mapping model constructed with the calibrated interference power as the horizontal axis and the time deviation as the vertical axis. During the test, as the interference signal injection module 300 gradually changes the interference power according to a preset step, the data acquisition and judgment module 500 records the corresponding time deviation value at each power point and fits these data points into a continuous curve. This curve intuitively reflects the dynamic trend of the timing accuracy of the device under test 700 as the interference intensity changes: in the low interference region, the curve usually remains stable, indicating that the device has good anti-interference capability; when the interference power exceeds a certain critical value, the curve will rise sharply, indicating that the timing accuracy begins to deteriorate significantly or even lose synchronization. This anti-interference tolerance curve, generated based on measured data, overcomes the limitation of traditional tests that only give a qualitative conclusion of passing or failing, enabling the anti-interference capability of the device under test 700 to be quantitatively characterized, providing an objective basis for equipment selection, fault diagnosis, and algorithm optimization.

[0041] Further, the interference signals include in-band interference signals and out-of-band interference signals. The data acquisition and determination module 500 is configured to: based on the anti-interference margin curve, determine the timing synchronization state of the device under test 700 when the interference power of the out-of-band interference signal reaches a first preset threshold; determine the timekeeping accuracy state of the device under test 700 when the interference power of the in-band interference signal reaches a second preset threshold; verify whether the device under test 700 outputs an interference detection flag bit when the interference power reaches a third preset threshold. Specifically, these three determination logics constitute the integrated intelligent analysis core of the system. The first determination is directed at out-of-band interference, which mainly examines the radio frequency front-end filtering performance and synchronization maintenance capability of the device under test 700. When the out-of-band interference power reaches the first preset threshold, if the device under test 700 can still maintain timing synchronization and the time deviation does not exceed the allowable range, it is determined that its out-of-band rejection capability is qualified. The second determination is directed at in-band interference. Since the in-band interference is directly superimposed on the useful signal and has a more serious impact on the receiver, the focus is on examining its timekeeping accuracy maintenance capability under strong interference. When the in-band interference power reaches the second preset threshold, if the time deviation of the device under test 700 still meets the specific accuracy requirement, it is determined that its timekeeping accuracy state is qualified. The third determination is used to verify the interference perception and alarm functions of the device under test 700 itself. When the interference power reaches the third preset threshold, the data acquisition and determination module 500 will check whether a clear interference detection flag bit appears in the serial port output of the device under test 700, so as to confirm that the device has the capability of actively reporting abnormalities in a harsh electromagnetic environment.

[0042] It should be understood that the above-mentioned first preset threshold, second preset threshold and third preset threshold are all configurable parameters, rather than fixed constants. In practical applications, there are significant differences in the requirements for timing accuracy and anti-interference capability in different industries and different application scenarios. For example, in the power dispatching automation scenario, the requirement for the stability of timing synchronization is extremely high, and the first preset threshold may be set relatively strict; while in some low-speed Internet of Things terminal scenarios, the tolerance for instantaneous timing accuracy is relatively high, and the second preset threshold can be appropriately relaxed. Similarly, the setting of the third preset threshold also depends on the sensitivity design of the interference detection algorithm of the device under test 700 itself. In this application, by decoupling the determination logic from the specific thresholds, the same set of detection system can adapt to diversified test standards and requirements through parameter configuration, avoiding the problem that the applicable scope of the system is limited due to hard-coded thresholds. In addition, in addition to the above three threshold-based discrete determinations, the data acquisition and determination module 500 can also calculate derived indicators such as the area under the curve, inflection point position, and slope change rate based on the complete anti-interference margin curve, so as to comprehensively evaluate the anti-interference performance of the device under test 700 from more dimensions, and further improve the engineering reference value of the detection results.

[0043] Embodiment 2: as Figure 3As shown, this embodiment provides a satellite navigation timing accuracy detection method, applied to the satellite navigation timing accuracy detection system described in the foregoing embodiments. This method automates the detection process and ensures the reproducibility of the results by transforming the system hardware architecture into a standardized timing operation procedure. Specifically, the method includes the following steps: Step S1: Preheat the system in the electromagnetic shielding test space 100, and calibrate the interference power of the interference signal at the antenna position of the device under test 700 based on the power detection component.

[0044] Specifically, system preheating is to ensure that the electronic components inside the satellite navigation signal simulation module 200, interference signal injection module 300, and time deviation measurement module 400 reach thermal equilibrium, eliminating the impact of temperature drift on test accuracy. Based on this, the power calibration step is crucial. Unlike the conventional approach of setting power only at the instrument output, this step utilizes a power detection component to directly measure spatial power at the antenna aperture of the device under test 700. The data acquisition and judgment module 500 controls the interference signal injection module 300 to traverse preset attenuation levels and simultaneously records the actual power value fed back by the power detection component, thereby establishing a power control lookup table for the target power, attenuator setting, and measured power. This step physically eliminates system errors introduced by cable transmission loss, connector impedance mismatch, and differences in spatial propagation paths, ensuring that the interference intensity injected into the device under test 700 in subsequent tests is accurately known and controllable, laying a physical benchmark for constructing a high-precision quantitative mapping relationship.

[0045] Step S2: Under the condition of no interference signal injection, based on the frequency reference signal and time reference signal output by the external time reference device 600, measure the baseline time deviation of the time signal output by the device under test 700 relative to the time reference signal.

[0046] Specifically, this step aims to establish a performance reference system for the device under test (DUT) 700 under an ideal electromagnetic environment. The data acquisition and judgment module 500 continuously collects time deviation data over a period of time through the time deviation measurement module 400 and calculates its statistical characteristics as a baseline value. This baseline data is not only used to verify whether the test system and the DUT 700 are in normal working condition, but more importantly, it serves as a benchmark for subsequent evaluation of the impact of interference. Only by clearly defining the background noise and inherent deviation under interference-free conditions can the performance degradation caused solely by the interference signal be accurately identified in subsequent steps, thereby ensuring the objectivity and accuracy of the test results.

[0047] Step S3: Inject interference signals into the device under test 700 according to the preset steps, and simultaneously collect time deviation and radio frequency status data under different interference powers.

[0048] This step is the core of obtaining the dynamic response characteristics of the device under test (DUT) 700, and specifically includes a sensitivity test sub-step and an anti-interference test sub-step to comprehensively cover different test dimensions.

[0049] During the sensitivity test sub-step, the power of the satellite navigation signal is reduced according to the preset power reduction step, and the acquisition sensitivity and tracking sensitivity of the device under test 700 are recorded.

[0050] Specifically, the data acquisition and judgment module 500 controls the satellite navigation signal simulation module 200 to gradually reduce the output signal strength from a high power level with fixed step sizes. At each power point, the system monitors the positioning status and timing continuity of the device under test (DUT) 700. When the DUT 700 transitions from normal positioning to loss of lock or fails to complete the initial positioning, the corresponding power level is recorded as the acquisition sensitivity; when the DUT 700 cannot maintain continuous timing for more than a preset duration, the corresponding power level is recorded as the tracking sensitivity. This power reduction scanning mechanism can accurately capture the performance boundaries of the DUT 700 in weak signal environments, reflecting the limits of its RF front-end and baseband processing algorithms.

[0051] When performing the anti-interference test sub-step, the interference power is increased in preset power increments, and each power level is maintained for a preset time. The time deviation, number of visible satellites, and carrier-to-noise ratio corresponding to each power point are recorded.

[0052] Specifically, unlike sensitivity testing, anti-interference testing employs a power-up strategy. The data acquisition and judgment module 500, based on the power control lookup table established in step S1, precisely controls the interference signal output by the interference signal injection module 300 to the target strength. Crucially, after each adjustment of the interference power, the system forcibly maintains a preset stable period until the internal loop of the device under test (DUT) 700 is relocked and its state stabilizes before synchronously reading multi-dimensional data such as time deviation, number of visible satellites, and carrier-to-noise ratio (CNR). This timing control logic effectively avoids data fluctuations caused by the device's transient response not converging, ensuring that the data at each test point accurately reflects the steady-state performance of the DUT 700 under that interference intensity. Simultaneously, synchronously acquiring the number of visible satellites and CNR allows for verification of the cause of time deviation changes from two auxiliary dimensions: signal quality and geometric distribution, preventing misjudgment of multipath effects or obstruction as interference.

[0053] Step S4: Construct a mapping relationship based on the acquired time deviation and interference power, and output the timing accuracy judgment result based on the mapping relationship and radio frequency status data.

[0054] Specifically, an anti-interference tolerance curve is generated based on the time deviation corresponding to each power point recorded in the anti-interference test. The data acquisition and judgment module 500 fits or interpolates a series of discrete data points obtained in step S3 to generate a continuous curve with interference power as the horizontal axis and time deviation as the vertical axis. This anti-interference tolerance curve intuitively represents the quantitative mapping relationship between the timing accuracy of the device under test 700 and the change in interference intensity. On this basis, the system further combines the baseline time deviation obtained in step S2 and the preset judgment threshold to automatically calculate the degree of performance degradation, and integrates radio frequency status data such as the number of visible satellites and carrier-to-noise ratio to output a final judgment report including the timing synchronization status, timekeeping accuracy status, and interference detection function verification results. There are strict data dependencies between the steps of the entire method process: the calibration data in step S1 ensures the accuracy of the excitation source in step S3, and the baseline data in step S2 provides a reference benchmark for the degradation assessment in step S4, thereby ensuring that the final test results have high reproducibility and engineering practical value.

[0055] It should be understood that although this embodiment describes a specific test sequence, in other embodiments, the execution order of sub-steps can be adjusted according to test requirements, or only one type of test can be performed. Similarly, the preset step size, duration, and data acquisition frequency can be adaptively configured according to the type and application scenario of the device under test 700. As long as a quantitative mapping relationship between interference power and timing accuracy can be established, it falls within the protection scope of this application.

[0056] Example 3: In this example, the satellite navigation timing accuracy testing system and method provided in the preceding examples are applied to a BeiDou timing performance testing scenario for power grid edge equipment to verify the effectiveness and practicality of the technical solution in actual engineering applications. In this application scenario, the device under test 700 is specifically a Class I BeiDou timing and positioning module built into a transmission line monitoring terminal. These devices are deployed long-term on outdoor towers or around substations, directly exposed to complex electromagnetic environments. Their timing accuracy and anti-interference capabilities directly affect the stability of core services such as power dispatching and fault recording.

[0057] Specifically, for this application scenario, the parameter configurations of each module in the system are as follows: The satellite navigation signal simulation module 200 is configured to output satellite navigation signals at the BDS B1I frequency point to simulate a real BeiDou timing environment. The interference signal injection module 300 is configured to generate two typical types of interference signals: one is an in-band interference signal with a center frequency of 1561.098MHz, used to simulate malicious suppression or adjacent-channel interference in the same frequency band; the other is an out-of-band interference signal in the 1447MHz-1467MHz frequency band, used to examine the filtering performance and out-of-band suppression capability of the RF front-end of the device under test (DUT) 700. It should be understood that the above frequency band selection is a preferred example based on the BeiDou B1I system and the specific electromagnetic environment characteristics of the power industry. In other application scenarios, it can be flexibly adjusted according to the satellite navigation system supported by the DUT and the actual interference environment.

[0058] Regarding the judgment logic, the data acquisition and judgment module 500 presets specific judgment thresholds. For time synchronization accuracy testing, the judgment threshold is set as follows: the root mean square (RMS) value of the time deviation does not exceed 1 μs, and no jump greater than 3 μs occurs in 1000 seconds of continuously acquired data. For anti-interference performance testing, the first preset threshold for out-of-band anti-interference is set at 15 dBm, meaning that when the out-of-band interference power reaches 15 dBm, the device under test 700 should still be able to maintain time synchronization with a time adjustment of no more than 200 ns per second; the second preset threshold for in-band anti-interference is set at Pn + 40 dB, where Pn is the noise floor power of the active antenna of the device under test 700. Under this interference intensity, the device under test 700 should maintain time synchronization or timekeeping accuracy that meets the standard requirements. Furthermore, the third preset threshold for interference detection function verification is set to Pn+20dB. When the interference power reaches this level, the data acquisition and judgment module 500 reads the NMEA statement or custom protocol frame output by the device under test 700 via the serial port to verify whether it outputs a clear interference detection flag. These thresholds are not fixed and can be modified by the user through the configuration interface of the data acquisition and judgment module 500 according to the level of the device under test or specific project requirements, reflecting the system's versatility and scalability.

[0059] During testing, the operator only needs to select the Class I test template for the power Beidou module in the software interface of the data acquisition and judgment module 500. The system will then automatically call up the above parameter configuration and sequentially perform system preheating and spatial power calibration, baseline time deviation measurement, sensitivity testing, anti-interference testing, and interference detection function verification according to the standardized process described in Example 5. After the test is completed, the data acquisition and judgment module 500 automatically summarizes all test data and generates a test report that includes timing accuracy statistics, acquisition / tracking sensitivity values, anti-interference tolerance curves, and pass / fail conclusions for each indicator.

[0060] Compared with traditional outdoor satellite testing, the testing scheme shown in this embodiment has significant technical advantages. First, regarding result reproducibility, since the test is conducted within an electromagnetically shielded testing space of 100, the influence of weather changes, geographical differences, solar activity, and uncontrollable interference sources in the real environment on the test results is completely eliminated. This ensures high consistency of test results at different times and locations, serving as a reliable basis for equipment network acceptance testing. Second, regarding testing efficiency, the system integrates signal simulation, interference injection, time and frequency measurement, and automatic judgment functions. A single software program can complete all the test items specified in the standard, avoiding the tedious process of switching wiring between different devices and manually recording data, significantly shortening the testing cycle. Finally, regarding cost control, by reusing the external timing reference device 600 instead of the expensive internal atomic clock, and using a power meter instead of a spectrum analyzer for spatial power calibration, the system construction and maintenance costs are significantly reduced while ensuring testing accuracy, enabling grassroots electrical research institutes and testing organizations to possess complete testing capabilities.

[0061] It should be noted that the specific signal frequency bands, power thresholds, acquisition durations, and judgment criteria mentioned in this embodiment are merely preferred implementation methods adapted to the specific application scenario of BeiDou timing accuracy detection for grid edge devices, and do not constitute a limitation on the scope of protection of this application. Without departing from the core technical concept of this application, those skilled in the art can adaptively adjust or replace the above parameters according to the timing detection needs of other industries, and such adjustments should all be covered within the scope of protection of this application.

[0062] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of variations or substitutions within the technical scope disclosed in this application, such as adjustments to the hardware topology of each module, changes to the signal standard, adaptive configuration of the judgment threshold, or adjustments to the order of the test process, as long as they do not depart from the core technical concept of this application regarding the reuse of external timing references, spatial interference power calibration, and the construction of a quantitative mapping relationship between interference intensity and timing accuracy. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A satellite navigation timing accuracy detection system, characterized in that, include: Electromagnetic shielding test space; The through-wall panel assembly is installed on the shielding wall of the electromagnetic shielding test space to enable signal transmission inside and outside the electromagnetic shielding test space while maintaining electromagnetic shielding effectiveness. A satellite navigation signal simulation module is configured to radiate satellite navigation signals to the device under test within the electromagnetic shielding test space. An interference signal injection module is configured to inject an interference signal into the device under test (DUT) and calibrate the interference power of the interference signal at the antenna position of the DUT based on a power detection component. The time deviation measurement module is configured to receive a frequency reference signal and a time reference signal output by an external time reference device, and to measure the time deviation of the time signal output by the device under test relative to the time reference signal based on the frequency reference signal and the time reference signal. The data acquisition and judgment module is configured to synchronously acquire the time deviation under different interference powers and the radio frequency status data output by the device under test based on the satellite navigation signal, and construct a mapping relationship based on the time deviation and the interference power to output the timing accuracy judgment result.

2. The satellite navigation timing accuracy detection system according to claim 1, characterized in that, The external reference input terminal of the time deviation measurement module is connected to the frequency reference output terminal of the external timing reference device to receive the frequency reference signal; The door opening channel of the time deviation measurement module is connected to the time reference output terminal of the external time reference device to receive the time reference signal; The closing channel of the time deviation measurement module is connected to the time signal output terminal of the device under test to receive the time signal.

3. The satellite navigation timing accuracy detection system according to claim 2, characterized in that, The frequency reference signal is a high-frequency reference signal, and the time reference signal is a second pulse time reference signal; The time deviation measurement module uses the high-frequency reference signal as a clock reference to measure the time difference between the second pulse time reference signal received by the door opening channel and the time signal received by the door closing channel, so as to obtain the time deviation.

4. The satellite navigation timing accuracy detection system according to claim 1, characterized in that, The interference signal injection module includes a radio frequency signal generator, a power amplifier, an adjustable attenuator, a directional coupler, and the power detection component; The output terminal of the radio frequency signal generator is connected to the input terminal of the power amplifier, and the output terminal of the power amplifier is connected in series with the directional coupler and then connected to the transmitting antenna. The adjustable attenuator is disposed in the path between the radio frequency signal generator and the power amplifier, or in the path between the power amplifier and the directional coupler; The power detection component includes a power meter, and the coupling end of the directional coupler is connected to the power meter to calibrate the interference power at the antenna position of the device under test.

5. The satellite navigation timing accuracy detection system according to claim 4, characterized in that, The radio frequency signal generator is configured to generate in-band interference signals and out-of-band interference signals as the interference signals; The adjustable attenuator is configured to adjust the interference power in preset steps, and the data acquisition and judgment module establishes a power control lookup table based on the feedback data of the power meter to control the interference power.

6. The satellite navigation timing accuracy detection system according to claim 1, characterized in that, The radio frequency status data includes the number of visible satellites and the carrier-to-noise ratio; The data acquisition and judgment module is configured to synchronously acquire the time deviation, the number of visible satellites, and the carrier-to-noise ratio under different interference powers, and generate an anti-interference tolerance curve based on the time deviation and the interference power. The anti-interference tolerance curve characterizes the mapping relationship between the interference power and the time deviation.

7. The satellite navigation timing accuracy detection system according to claim 6, characterized in that, The interference signals include in-band interference signals and out-of-band interference signals; The data acquisition and judgment module is configured as follows: Based on the anti-interference tolerance curve, when the interference power of the out-of-band interference signal reaches a first preset threshold, the timing synchronization status of the device under test is determined. When the interference power of the in-band interference signal reaches a second preset threshold, the timekeeping accuracy status of the device under test is determined. When the interference power reaches the third preset threshold, verify whether the device under test outputs an interference detection flag.

8. The satellite navigation timing accuracy detection system according to claim 1, characterized in that, The wall-penetrating plate assembly includes an RF wall-penetrating plate, a serial port wall-penetrating plate, and a time-frequency signal wall-penetrating plate; The radio frequency through-wall plate is used to transmit the satellite navigation signal and the interference signal; The serial port through-wall plate is used to transmit serial port data of the device under test. The time-frequency signal through-wall plate is used to transmit the time signal; The inner walls and test platform of the electromagnetic shielding test space are covered with wave-absorbing material.

9. A method for detecting satellite navigation timing accuracy, applied to a satellite navigation timing accuracy detection system as described in any one of claims 1 to 8, characterized in that, include: The system was preheated in the electromagnetic shielding test space, and the interference power of the interference signal was calibrated at the antenna position of the device under test based on the power detection component. In the absence of interference signal injection, based on the frequency reference signal and time reference signal output by the external time reference device, the baseline time deviation of the time signal output by the device under test relative to the time reference signal is measured. The interference signal is injected into the device under test according to a preset step, and the time deviation and radio frequency status data under different interference powers are collected simultaneously. A mapping relationship is constructed based on the collected time deviation and interference power, and a timing accuracy determination result is output based on the mapping relationship and the radio frequency status data.

10. The satellite navigation timing accuracy detection method according to claim 9, characterized in that, The process of injecting the interference signal into the device under test at preset steps and simultaneously collecting time deviation and radio frequency status data under different interference powers includes: Perform sensitivity testing: reduce the power of the satellite navigation signal according to the preset power reduction steps, and record the acquisition sensitivity and tracking sensitivity of the device under test; Perform anti-interference test: Increase the interference power in preset power increments, maintain each power level for a preset time, and record the time deviation, number of visible satellites, and carrier-to-noise ratio corresponding to each power point; The step of constructing a mapping relationship based on the collected time deviation and the interference power includes: generating an anti-interference tolerance curve based on the time deviation corresponding to each power point recorded in the anti-interference test.

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