79 results about "Repeatability" patented technology

The invention discloses a scene granularity interface test case generation method based on multiple agents, and the method comprises a plurality of large language model agents and related components, namely context memory, an observer, a decision maker, an executor, a supervisor, a recorder and a to-be-tested application. An observer identifies the interface control, detection and attribute identification of the control are effectively focused, and it is ensured that accurate data input is provided for subsequent testing steps. Based on the output of an observer, a decision maker generates a detailed plan of the next operation according to the current page state, and an operation strategy can be independently formulated, so that test generation is supported by business scene logic. And an executor analyzes and executes the generated plan operation, carries out test operation strictly according to the plan, and ensures the traceability and repeatability of the test process. Furthermore, the supervisor verifies whether the operation is executed according to the plan and meets the requirements of the target scene, and makes corresponding feedback according to the check result, thereby ensuring that the wrong operation is corrected in time, avoiding the continuous accumulation of errors, and ensuring the effectiveness of each test step. The recorder is responsible for storing the execution instruction and the context information of the test process to the context memory, and the operation history and result in the test process can be traced through the test context information, so that a better decision can be made in the subsequent iteration, and the result export after the test is completed can be effectively supported. And after the recording is finished, the test generation enters the next iteration until the coverage of the test scene is finished.

The invention provides a circuit test system and method and related equipment, and the test system comprises a test mold, electronic test equipment and computing equipment, can test a plurality of circuit parameters in parallel, can complete a large number of tests in a short time for circuit boards produced in batches, can run according to a preset program, and is high in test efficiency. The test result is more accurate and stable, a high-precision test instrument can be equipped, tiny voltage and current changes can be accurately measured, the device has the characteristics of high efficiency and stability, the test cost can be reduced, defective circuit boards can be found and removed in time, defective products are prevented from flowing into the next process, the defective products are prevented from flowing out, and the rework cost is reduced. The test data can be automatically recorded and stored, subsequent data analysis and quality tracing are facilitated, and the test system has obvious advantages in the aspects of efficiency, precision, cost, data management, repeatability and the like and is suitable for large-scale and high-precision circuit board production requirements.

The invention discloses a system and a method for testing the vacuum thermal sublimation loss rate of ice-containing soil, and belongs to the technical field of vacuum thermal sublimation simulation experiments of space exploration. The test system comprises a data acquisition system, a sample preparation chamber, a first vacuum low-temperature chamber, a second vacuum chamber and an in-place detection simulation vacuum chamber, and can timely place a prepared sample in a test condition, so that the prepared sample is prevented from changing in advance when not entering the simulation vacuum chamber; therefore, the initial condition of the sample is effectively controlled, the accuracy and repeatability of measured data are ensured, meanwhile, the change process of the monitored sample from the initial state to the target condition can be implemented, and in-situ measurement is realized. The test method comprises the influence of factors such as heating temperature, star soil heap type, sample throwing, sample physical property parameters and the like on the vacuum thermally-induced sublimation loss rate of the ice-containing star soil, provides correction parameters for the real water content of the original star soil, and also provides data support for improving the extraction efficiency of lunar soil water ice.

The present invention discloses a method and application for correcting the error of a special gear in double-flank meshing measurement of gears. The method first adjusts the special gear and the product gear on a double-flank meshing measuring instrument so that the two are meshed, and the tooth grooves and teeth of the two gears are marked in sequence; the two gears are rotated in double-flank meshing, and a center distance data set is collected during meshing; the special gear is rotated again in double-flank meshing with the product gear returned to its initial position, and a center distance data set is obtained again; an error correction value curve for the special gear is obtained based on the two sets of center distance data sets, and the double-flank meshing comprehensive deviation curve and the error correction value curve are linearly superimposed at the same phase to obtain the radial comprehensive deviation value of the product gear after the special gear error is corrected. The present invention improves the measurement accuracy and repeatability of double-flank meshing measurement and eliminates the influence of the special gear's own error on the measurement.

This invention discloses a method and system for stability analysis of metrological instrument measurement results, relating to the field of time series data analysis technology. The method includes measurement data stream alignment, construction of baseline features for measurement result stability, three-state feature decomposition, and stability analysis of metrological instrument measurement results. Repeatability, trend, and structural features of the measurement results are extracted to construct a baseline feature vector for measurement result stability. A three-state feature decomposition method based on baseline constraints is used to decompose the stability changes of the measurement results into drift, noise, and jump features. Based on the baseline features and the three-state feature decomposition results, a comprehensive analysis of the stability state and changing trends of the metrological instrument measurement results is performed. This invention enables refined and causally distinguishable analysis of the stability of metrological instrument measurement results under complex operating conditions and multi-state operation, providing a reliable basis for instrument operating status assessment and measurement result reliability judgment.

The present application relates to the technical field of power distribution equipment, and particularly relates to a ring main unit gas chamber temperature and humidity test method and device based on dynamic frost layer regulation. The method tests the ring main unit gas chamber at multiple temperature points in a high-low temperature test chamber, and dynamically regulates the thickness of the frost layer formed by a mirror surface humidity detection unit during dew point measurement to achieve rapid and accurate adjustment of the humidity in the gas chamber, thereby avoiding the traditional inefficient gas replacement process, allowing the entire humidity adjustment process to be completed within 10 minutes, greatly shortening the multi-working-condition temperature and humidity test cycle. The control terminal automatically coordinates the high-low temperature test chamber, electromagnetic valve, pump set and detection unit to achieve full closed-loop operation from temperature regulation, humidity measurement to frost layer regulation, supports 24-hour continuous operation, avoids operation errors and data fluctuations caused by manual intervention, and significantly improves the reliability and repeatability of test data.

The invention provides a repetitive anomaly judgment method and system of a measuring instrument and a computer readable medium. The repetitive anomaly judgment method comprises the following steps: acquiring a real-time image and / or real-time metering data of the metering instrument in a metering process; according to the real-time image and / or the real-time metering data, judging whether the metering instrument performs repeated actions in the metering process or not; and if the repeated actions occur, acquiring a plurality of effective metering data corresponding to the repeated actions, calculating a repeatability error of the effective metering data, and if the repeatability error exceeds a verification standard, judging that the metering instrument has repeatability abnormity. According to the invention, on the premise that the actual application of the measuring instrument is not interfered, the repetitive abnormity of the measuring instrument can be found in time, whether the measuring instrument needs to be calibrated is judged, and the measuring instrument is submitted for inspection in time, so that the calibration efficiency of the measuring instrument is improved.

The invention relates to a high-strength aluminum alloy residual stress testing device and method in the technical field of material mechanical property testing, the high-strength aluminum alloy residual stress testing device comprises a rack, a clamping assembly used for clamping a sample and a cutting assembly used for cutting the sample are arranged on the rack, and a plurality of strain gauges are arranged in the middle of the bottom face of the sample at intervals in the cutting direction; according to the invention, the second jacking piece is arranged to apply accurate jacking force at the trisection position of the sample in the length direction, so that static deformation of the sample caused by self weight is effectively compensated, and systematic errors of the gravity on a measurement result are eliminated from the source; compared with a mode depending on follow-up algorithm compensation or tedious early-stage calibration in the prior art, the method does not need complex calculation or manual intervention, the operation process is simplified, the technical requirements for operators are reduced, a detector system is simpler and more reliable, and the repeatability and accuracy of testing are improved.

The invention discloses a calibration method based on a blasting vibration acquisition instrument, which comprises the following steps of: data acquisition: performing blasting tests at different delay times, recording vibration waveform data by using the acquisition instrument, synchronously counting bulk distribution after blasting, and establishing an associated database of the delay times and crushing effects; calibrating by an improved linear superposition method: decomposing an actually measured single-hole waveform by using Fourier series, adding a random variable to generate a simulation waveform, calculating a theoretical particle peak vibration velocity mean value at different delay times through Monte Carlo simulation, and comparing the actually measured particle peak vibration velocity of the acquisition instrument with a theoretical value; verifying the rock crushing effect: carrying out regression analysis on the calibrated vibration data and the rock crushing effect; testing stability and repeatability: repeatedly blasting under the same delay time, checking repeatability errors of data of the acquisition instrument, and analyzing the influence of background noise on the acquired data; and calibration result output: establishing a delay time-vibration parameter-crushing effect calibration curve.

The invention discloses a borescope calibration method and a matched portable calibration device, and belongs to the technical field of nondestructive testing and metering testing. The device comprises a base, a sliding block, a sliding base, a transmission mechanism, a line pattern standard ruler, a test line locking device and a standard block set (a two-dimensional resolution plate and a height and depth step gauge), can realize precise control of relative positions of a probe and a standard block, and supports field and outfield use. The calibration method comprises the steps of preparation before calibration, implementation of ten calibration items and data recording and analysis, and coverage of core parameters such as X / Y / Z three-axis indication error, depth of field, probe illumination and field angle through standardized processes such as environment quantitative control and multi-point repeated measurement. The borescope calibration method fills the blank of borescope calibration standards in China, reduces manual operation errors, improves the comprehensiveness, repeatability and traceability of calibration, is compatible with various borescopes, is suitable for the industries of aerospace, precision machinery and the like, and also can be referenced and implemented in the medical field.

The invention discloses a method for calculating the critical applicable depth of a sunken vertical shaft. The applicable depth of an existing sunken vertical shaft mostly depends on experience, the discreteness of the result is large, and the error between the result and the practical applicable depth is large. According to the method, the friction theory is taken as the reference, the test data is taken as the support, and the established quantitative parameterization calculation model can accurately express the critical applicable depth of the sunken shaft. The method adopted by the invention is based on theoretical calculation and test parameters, each parameter in calculation is clear in meaning and simple in application, a reference can be provided for calculation of the critical applicable depth of the sunken shaft under a complex stratum condition, a calculation result is high in reliability and repeatability, and the deviation between the calculation result and an engineering actual measurement result is small.

The application discloses a kind of limit bending radius and fatigue strength test method and device for flexible plate, including first support plate, second support plate and rotating mechanism;Wherein, the rotating mechanism includes horizontally arranged positive rotation shaft, and first rotating arm assembly is installed on the positive rotation shaft;The first support plate and the second support plate are adjacently arranged below the positive rotation shaft;The first rotating arm assembly connects the first support plate, so that the first support plate can be rotated relative to the positive rotation shaft, so that the included angle between first support plate and second support plate changes.The device is simple in structure, and is convenient to adjust;Different glass specifications can be quickly adjusted and test results are quickly obtained, and the repeatability is high;The method is simple to operate, and measurement data is accurate, and data repeatability and reliability are high.

The invention provides a gas-water separator high-fidelity test system and method, and belongs to the technical field of fuel cell auxiliary equipment performance test. Aiming at the problems of humidity reference distortion and poor separation efficiency measurement repeatability caused by pipeline condensation or evaporation in the existing test method, a technical scheme taking dew point locking as a core is provided. According to the system, thermodynamic saturated wet air is generated through the gas humidifying device, and the wall surface temperature is always higher than the gas dew point temperature by at least 2 DEG C by adopting a pressure-resistant pipeline with whole-course heat insulation protection, so that secondary phase change is avoided; on the basis, a multi-parameter cooperative control unit can be selected, and heating, humidifying and droplet injection parameters can be dynamically adjusted based on real-time dew point calculation. According to the method, high-repeatability testing can be achieved without depending on closed-loop control, and working condition switching steady state establishment can be completed within 2-5 minutes in a closed-loop mode. According to the invention, the separation efficiency measurement precision and the test efficiency are obviously improved, and the method is suitable for research and development verification and batch inspection of the gas-water separator for the hydrogen fuel cell.

The present invention discloses an ultrasonic device and method for detecting the elastic modulus of a small-sized thin plate sample, which belongs to the technical field of ultrasonic measurement. The ultrasonic device for detecting the elastic modulus of a small-sized thin plate sample comprises a measuring tool (1), a signal generator (2), a first low-pass filter (3), a second low-pass filter (4) and a high-speed sampling oscilloscope (5). The device and method proposed by the present invention can measure hard, small-sized, thin samples that are difficult to measure with existing solutions. The method has the advantages of convenient measurement, high reliability, high success rate, good test repeatability, etc. The method is of great significance for the rapid and accurate detection of the physical properties of small-sized, thin, hard samples synthesized in the laboratory.

The invention discloses a device and a method for detecting the straightness of an ultra-precise hydrostatic guideway, and the device comprises a calibration part, the calibration surface of which is configured to be perpendicular to a first guideway surface or a second guideway surface in a to-be-detected plane of the hydrostatic guideway, so as to adapt to the measurement in different directions, and the first guideway surface is perpendicular to the second guideway surface; and the displacement sensor is fixed on the sliding plate, and a measuring head of the displacement sensor is perpendicular to the calibration surface, so that the displacement sensor and the calibration surface form a non-contact measurement pair in the moving process of the sliding plate, and displacement data are obtained by sensing the change of the distance between the displacement sensor and the calibration surface. According to the detection device, the displacement sensor and the calibration piece are adopted to form a non-contact measurement pair, so that high-repeatability measurement is realized by virtue of nanoscale precision of the sensor while a contact force error is eliminated.

A method (1000) for determining the repeatability variance of a given measurement process to be carried out on a test object (1), comprising the following steps:providing (100) at least one test object (1);determining (200) at least one measurement parameter (2) of the measurement process, on which measurement parameter the result of the measurement process also depends, in addition to the properties of the test object (1), which properties are to be measured and are provided in the form of a measurement variable (3) to be considered;determining a variation range (21) for the at least one measurement parameter (2);carrying out (300) a plurality of measurements on the test object (1) for various values (210, 211, 212) of the at least one measurement parameter (2) within the relevant variation range (21), so that at least one distribution (310, 311, 312) of the measured values of the measurement variable (3) is obtained with at least one measure of dispersion (310a, 311, 312a), in particular a dispersion range;analyzing the sought-after repeatability variance from the at least one measure of dispersion (310a, 311a, 312a) of the at least one distribution (310, 311, 312) of the measured values obtained.

The utility model discloses a glue viscosity detection device which comprises a detection device main body and a fixing frame arranged at the upper side position of the detection device main body, the detection device main body is connected with an external power supply to supply power, and a display screen is arranged at the inner position of the front side of the detection device main body. A control button is arranged at the lower side position of the display screen, a testing piece is arranged at the lower side position of the fixing frame, a testing adhesive tape is connected to the front side position of the testing piece in an adhering mode, unexpected variables in the testing process are directly reduced by using a tensioning device, and therefore the random error of a testing result is reduced; therefore, the test result is more accurate, the real viscosity of the glue can be reflected more accurately, and the repeatability of the test is improved because the external interference is reduced, which means that the consistent result can be obtained by multiple tests under the same condition. The method is crucial to scientific research and quality control, and the reliability and consistency of the test are ensured.

This invention relates to the field of material aging testing technology and provides a method for testing the UV transmittance decay of adhesive tape, comprising the following steps: S1: Calculate and output the UV aging resistance index based on the ratio of the transmittance of the adhesive tape sample after a first preset aging time to the initial transmittance, the ratio of the transmittance after a second preset aging time to the initial transmittance, and the absolute value of the difference between the transmittance after the first preset aging time and the transmittance after the second preset aging time. This invention not only calculates the UV aging resistance index but also comprehensively incorporates indicators such as repeatability bias, goodness of fit, and residual fit to output a test accuracy evaluation index. This index can quantify the reliability of the testing process, avoiding misjudgments that may be caused by traditional methods relying solely on transmittance as a single indicator, and significantly improving the scientific validity and reliability of the test results.

The utility model relates to the technical field of component strength detection, and discloses strength detection equipment for component production. Comprising a workbench and further comprises a side plate arranged at the top of the workbench, and a fixing frame is fixedly connected to the top of the workbench; and the limiting mechanism is arranged on one side of the side plate and is used for conveniently limiting the detection equipment when the detection equipment moves, and the limiting mechanism comprises a limiting frame fixed on one side of the side plate. The sensor convenient to limit can ensure that each test is carried out at the same or preset position, so that the repeatability and accuracy of test data are improved, the clamping mechanism is arranged to facilitate clamping and positioning of parts, the equipment convenient to clamp and position can ensure that the parts are kept at the correct position and direction in the test process, and the test efficiency is improved. Therefore, the accuracy and reliability of test data are improved.

The application relates to a privacy-considered automatic driving scene data repeatability measurement method, which comprises the following steps: obtaining dynamic layer data and static layer data based on an automatic driving scene; extracting key features from the dynamic layer data; generating a static layer first-level label and a second-level label based on the static layer data; encrypting and encoding the dynamic layer hidden features, and calculating the similarity of the dynamic layer data; respectively encoding and processing the static layer first-level label and the second-level label by using different encoding modes; calculating the proportion of the same type of scene in a scene library based on the encoding result of the static layer first-level label; in the same type of scene, generating the similarity measurement result of the static layer data by using the encoding result of the static layer second-level label; comprehensively calculating the similarity of the static layer and the dynamic layer data, and obtaining the same type of scene repeatability measurement result according to the importance weight; and calculating the scene repeatability result based on the same type of scene repeatability measurement result and the proportion. Compared with the prior art, the application can realize the repeatability measurement under the encryption state of scene data.

The utility model discloses equipment for measuring the shear strength of a material and the stripping force of a coating. The equipment comprises a rack, the test board is arranged on the rack; the scraper knife is arranged on the rack and can move in the up-down direction and the front-back direction relative to the rack; the Z-axis driving mechanism is arranged on the rack and drives the scraper knife to move up and down relative to the rack; the Y-axis driving mechanism is arranged on the rack and drives the scraper knife to move in the front-back direction relative to the rack; the Z-axis direction force sensor is used for detecting the stress of the scraper knife in the vertical direction; the Y-axis direction force sensor is used for detecting the stress of the scraper knife in the front-back direction; the Z-axis direction displacement sensor is used for detecting the displacement of the scraper knife in the vertical direction; and the Y-axis direction displacement sensor is used for detecting the displacement of the scraper knife in the front-back direction. According to the utility model, the test process is convenient, the test precision is high, the test data repeatability is good, the test result can be reproduced, and the test efficiency is high.

The invention provides a method for measuring the surface type of an equidistant Fresnel structure product, and relates to the technical field of product surface type measurement. The method sequentially comprises the steps that a UA3P atomic force probe is used for measuring the equidistant Fresnel part in a contact mode, and original coordinate point data are exported; an equidistant Fresnel regression model is constructed through an MATLAB (matrix laboratory) stair function; original measurement coordinates and model point location data are combined in Excel, and aspheric surface structure contour point locations are restored; a Data Tool tool is used for converting the splicing point positions into binary codes compatible with UA3P; calling a UA3P general aspheric structure equation and a coefficient; and filtering a high-angle interference data area with a draft angle greater than 60 degrees, intercepting real surface type data and outputting a result. The problems that in the prior art, a Fresnel structure is difficult to restore, the risk of probe breakage is high, and data splicing is complex are solved, the model building loss is converged to the nanoscale, the real object repeatability measurement error is smaller than or equal to 0.2 micrometer, quantitative and standardized management and control are achieved, and the measurement efficiency is improved by 40% or above.

The invention relates to the technical field of anti-freezing testing, in particular to a method and system for testing the anti-freezing performance of an anti-frost-crack water supply pipe, and the method comprises the following steps: S1, selecting an anti-frost-crack water supply pipe sample to be tested, ensuring that the length and diameter parameters of the sample are consistent, and pretreating the sample to ensure the accuracy of a test result; s2, respectively placing the treated samples in a set low-temperature environment, and observing and recording the frost crack resistance of the samples at each temperature; s3, establishing an anti-freezing performance mathematical model by utilizing the characteristic that the anti-freezing crack performance of the water supply pipe sample in each low-temperature state is changed and has a certain regularity; s4, treating a to-be-detected water supply pipe sample according to the same pretreatment steps, placing the sample in a preset low-temperature environment, recording the frost crack resistance performance of the sample, substituting the frost crack resistance performance into the established mathematical model, and calculating the frost resistance performance of the sample at each temperature; s5, setting a qualified standard of the anti-freezing performance according to an industrial standard and a user demand; and the accuracy and the repeatability of the test are improved.

The application discloses a kind of carbonitriding spline surface hardness microhardness testing methods, comprising the following steps: cutting along the section of carbonitriding spline to be detected to prepare the metallographic sample of tooth part;With spline tooth surface midpoint as origin O, with spline tooth surface midpoint profile line as X axis, establish coordinate system and determine reference line, select multiple test points on reference line, test and record the microhardness value of each test point;Calculate average, standard deviation, data repeatability;Judge whether data repeatability is greater than or equal to 5%, when data repeatability >=5%, select new test point on reference line, and record the microhardness value of the test point and calculate data repeatability R, until data repeatability R >=5%, otherwise, average is used as final microhardness value.The application has the advantages of accurate data detection and high efficiency.

The application provides an explosive impact pressure testing device, and relates to the technical field of explosives and blasting engineering. The testing device simulates the hole wall where the explosive is located in the actual blasting through a testing pipe, and collects the test data of the detonation products generated after the explosion of the explosive, such as time, instantaneous impact pressure of the detonation products on the inner wall surface of the testing pipe and the like, by cooperating with an information collector. Meanwhile, the detonation products are reduced in energy carried when being discharged from the outlet end of the pressure relief pipe in the form of reverse folding and mutual collision by means of the main pressure relief channel and the auxiliary pressure relief channel, so that the testing device has good repeatability and low external impact power, reduces the high standard dependence of the testing device on the testing site, and avoids the problems of poor test repeatability, high cost, inconvenient operation and difficulty in obtaining stable and reliable data caused by the influence of factors such as geological conditions and charging parameters during the on-site blasting test.

The invention discloses a method for quantitatively testing the loading capacity of air floccules on the surface of a bubble, belongs to the technical field of bubble loading, and can solve the technical problems that an existing method for testing the loading capacity of mineral particles on the surface of the bubble has measurement errors, quantitative testing cannot be achieved and the like. The specific numerical value of the bubble loading capacity is directly obtained by cutting out the adhered air floccules on the surfaces of the bubbles, drying and weighing the adhered air floccules. According to the invention, the precision and repeatability of measurement can be improved, so that the result is more reliable and accurate.

The invention discloses a standard concrete test piece and a calibration method of a concrete test piece size non-contact measurement system using the standard concrete test piece, the standard concrete test piece comprises a test piece body, the test piece body is a rectangular block body, the test piece body is provided with a size detection module, an angle detection module and a flatness detection module, and the size detection module is connected with the angle detection module. The size detection module has three different size standard values set for the lengths of the test piece body on three orthogonal dimensions, and the flatness detection module has three different flatness standard values set for steps of the test piece body on three orthogonal dimension planes. The angle detection module has three different angle standard values for setting included angles which are formed by three groups of adjacent surfaces of the test piece body and are positioned on three orthogonal dimension planes. According to the invention, the number of standard components is reduced, the storage and transportation cost is reduced, the measurement error caused by the difference between test pieces is effectively weakened, the accuracy and repeatability of the measurement result are improved, and the detection efficiency is improved.

The present invention discloses a method for determining the parallel capacitance value when a PVDF charge mode tests an explosive shock load. This method uses an impact test device to simulate the explosive load and applies the same impact load to the PVDF. In each test, the PVDF is respectively connected in parallel with different capacitors. Secondly, the repeatability and variability of the test results are respectively evaluated by combining the intra-group correlation coefficient and the coefficient of variation. When the evaluation results meet the pre-determined test accuracy requirements, it can be considered that the influence of the electrical characteristics of the test circuit on the charge distribution can be ignored, that is, the reasonable value range of the parallel capacitance is determined. At this time, the explosive shock load obtained by the traditional charge mode calculation method is accurate. This method avoids the defects brought about by using a fixed parallel capacitance in the past and ignoring the influence of the test circuit and the test environment, and can obtain more accurate output charges, thereby improving the accuracy and applicable range of PVDF impact load testing.

The utility model relates to the technical field of adhesion force testing, and discloses an adhesion force testing mechanism of a bionic adhesion material, which comprises a bottom plate, the right side of the upper part of the bottom plate is fixedly connected with a measuring assembly, the measuring assembly is used for measuring the bionic adhesion material, the two sides of the upper part of the bottom plate are fixedly connected with fixing frames, and the fixing frames are used for fixing the bionic adhesion material. A second motor is fixedly connected to the front side of the fixing frame, a rotating shaft is fixedly connected to the output end of the second motor, gears are fixedly connected to the two sides of the outer portion of the rotating shaft, rack plates are connected to the upper sides of the gears in an engaged mode, and fixing frames are fixedly connected to the upper sides of the rack plates. According to the utility model, the purpose of repeated testing under different experimental conditions is realized, high repeatability and controllability of test data are ensured, personal errors are reduced, and different temperature conditions can be simulated and tested, so that the performance of a test material in practical application is tested.

The voltage fluctuation signals of the cross-correlation electrodes of a permanent magnet sodium flowmeter with vortex shroud were collected by experiment. The generalized cross-correlation was used to estimate the transit time. The amplitude fluctuation of the transit time was analyzed and a moving average model was established. The model of the transit time was analyzed in depth and was decomposed into a steady component and a fluctuation component. The steady component and the fluctuation component were related to the two indicators of the measurement accuracy, namely the indication error and the repeatability error. The parameter law of the steady component was analyzed and the ideal value of the instrument correction coefficient was obtained. The upper limit of the accuracy of the cross-correlation measurement was obtained according to the indication error introduced by the correction coefficient. It was pointed out that the poor linearity of the instrument was the reason for the limited accuracy. According to the characteristics that the fluctuation component was a linear combination of Gaussian white noise, a method of two-stage moving average filtering was proposed to weaken the fluctuation component and reduce the repeatability error, so as to improve the measurement accuracy and make it reach the upper limit of the accuracy.