Fall prediction method and system for absolute gravity measurement on moving platform

Abstract

The present application provides a method and system for predicting the fall of an absolute gravity measurement on a moving platform, which obtains the motion information of an installation platform used to install an absolute gravity measurement system; predicts the motion of the installation platform within a prediction time based on the motion information of the installation platform to obtain a prediction result; when the prediction result is less than a reference index, performs an absolute gravity measurement based on the absolute gravity measurement system on the installation platform, and the reference index is used to indicate the maximum motion information of the installation platform that the absolute gravity measurement system can withstand in the current scenario to achieve the target measurement accuracy. The method and system for predicting the fall of an absolute gravity measurement on a moving platform provided by the present application ensures that the measurement is carried out normally by predicting the best time for the fall measurement, which solves the problem that the traditional technology ensures the effective measurement by sacrificing the measurement accuracy.

Description

Technical Field

[0001] The present application relates to the field of gravity measurement technology, and in particular to a method and system for predicting the fall of absolute gravity measurement using a moving platform. Background Art

[0002] Shipborne ocean gravity measurement technology is the most effective means to obtain high-precision and high-resolution ocean gravity field information. Shipborne ocean gravity measurement technology is mainly achieved by continuous measurement by carrying relative gravimeters on surface ships. Since the shipborne measurement operation time is long, often calculated on a monthly basis, the drift error of the relative gravimeter on the ship has a non-negligible impact on the measurement accuracy, and calibration at the gravity base point greatly increases the measurement time and cost. Therefore, there is an increasing demand for the introduction of a moving platform absolute gravity measurement system for instant co-location correction. Compared with relative gravity measurement, the absolute gravity measurement system directly obtains the absolute value of gravity acceleration, and there is no drift problem. It is often used to obtain the reference value of the gravity field and calibrate the relative gravity measurement value.

[0003] There are two types of absolute gravity measurement systems for moving platforms: laser interferometry and atom interferometry. Both laser interferometry and atom interferometry absolute gravity measurement systems obtain absolute gravity acceleration by measuring objects or materials that are in free fall in a vacuum environment. However, both laser interferometry and atom interferometry absolute gravity measurement systems are easily affected by the state of the base on which the absolute gravity measurement system is installed. When the base is a moving platform, the measurement accuracy of the laser interferometry and atom interferometry absolute gravity measurement systems will be reduced or even impossible to measure due to the influence of the linear acceleration and angular motion of the platform.

[0004] The existing moving platform absolute gravity measurement system alleviates the impact of the violent movement of the base platform on the gravity measurement by reducing the falling measurement time of the object or material in free fall. Reducing the falling measurement time can reduce the impact of the base platform movement on the measurement during the falling measurement, thereby increasing the success rate of the falling measurement process, and then increasing the effective utilization rate of the falling measurement data. On the other hand, reducing the falling measurement time reduces the data collected in a single measurement, resulting in reduced measurement accuracy. Therefore, the traditional technology sacrifices measurement accuracy. Summary of the invention

[0005] Based on this, the present application proposes a method and system for predicting the fall of an absolute gravity measurement using a moving platform, in order to solve the problem that traditional technologies sacrifice measurement accuracy to ensure effective measurement.

[0006] In a first aspect, the present application provides a method for predicting the fall of a moving platform using absolute gravity measurement. The method comprises:

[0007] Obtaining motion information of a mounting platform for mounting an absolute gravity measurement system;

[0008] Predicting the movement of the installation platform within a prediction time according to the movement information of the installation platform to obtain a prediction result;

[0009] When the predicted result is less than a reference index, absolute gravity measurement is performed based on the absolute gravity measurement system on the installation platform, and the reference index is used to indicate the maximum movement information of the installation platform that the absolute gravity measurement system can withstand to achieve the target measurement accuracy.

[0010] In one embodiment, the obtaining of motion information of an installation platform for installing an absolute gravity measurement system includes: obtaining motion information of the installation platform based on a data acquisition device of the installation platform, the data acquisition device including at least one of an accelerometer, a gyroscope, a satellite positioning system, and a radio positioning system, and the motion information includes at least one of acceleration, velocity, and displacement.

[0011] In one embodiment, the falling prediction method of the moving platform absolute gravity measurement further includes:

[0012] Determine the relationship between lateral disturbance displacement and measurement accuracy;

[0013] Based on the relationship between the lateral disturbance displacement and the measurement accuracy, the reference index is obtained.

[0014] In one embodiment, predicting the movement of the installation platform within the prediction time according to the movement information of the installation platform to obtain the prediction result includes:

[0015] Using the motion information of the installation platform as a state variable;

[0016] The movement of the installation platform within the prediction time is predicted according to the state variables and the preset prediction method to obtain a prediction result.

[0017] In the second aspect, the present application also provides a falling prediction system for absolute gravity measurement of a moving platform. The falling prediction system for absolute gravity measurement of a moving platform comprises: an absolute gravity measurement system, a mounting platform, and a measuring device, wherein the absolute gravity measurement system is mounted on the mounting platform, and the measuring device is used to obtain the motion information of the mounting platform, and predict the motion of the mounting platform within the prediction time according to the motion information of the mounting platform to obtain a prediction result; when the prediction result is less than a reference index, the absolute gravity measurement system is used to perform absolute gravity measurement, and the reference index is used to indicate the maximum motion information of the mounting platform that the absolute gravity measurement system can withstand to achieve the target measurement accuracy.

[0018] In one embodiment, the falling prediction system of the moving platform absolute gravity measurement also includes: the measuring device is also used to determine the relationship between the lateral disturbance displacement and the measurement accuracy, and obtain the reference index based on the relationship between the lateral disturbance displacement and the measurement accuracy.

[0019] In the third aspect, the present application also provides a falling prediction device for absolute gravity measurement of a moving platform. The device includes: a data acquisition module for acquiring motion information of the installation platform; a data processing module for predicting the motion of the installation platform within the prediction time according to the motion information of the installation platform to obtain a prediction result; a judgment module for judging whether the prediction result is less than a reference index; and a measurement module for performing absolute gravity measurement when the prediction result is less than the reference index.

[0020] In one embodiment, the data acquisition module is also used to obtain motion information of the installation platform based on a data acquisition device of the installation platform, the data acquisition device includes at least one of an accelerometer, a gyroscope, a satellite positioning system, and a radio positioning system, and the motion information includes at least one of acceleration, velocity and displacement.

[0021] In one embodiment, the falling prediction device for absolute gravity measurement of the moving platform further includes a data analysis module for determining the relationship between the lateral disturbance displacement and the measurement accuracy, and obtaining the reference index based on the relationship between the lateral disturbance displacement and the measurement accuracy.

[0022] In one embodiment, the data processing module is further used to use the movement information of the installation platform as a state variable; based on the state variable and a preset prediction method, predict the movement of the installation platform within a prediction time to obtain a prediction result.

[0023] In a fourth aspect, the present application further provides a computer device, wherein the computer device comprises a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the steps of the method described in any one of the above embodiments are implemented.

[0024] In a fifth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of the method described in any one of the above embodiments are implemented.

[0025] In a sixth aspect, the present application further provides a computer program product, wherein the computer program product comprises a computer program, and when the computer program is executed by a processor, the steps of the method described in any one of the above embodiments are implemented.

[0026] The moving platform absolute gravity measurement fall prediction method and system provided in the present application obtains the motion information of the installation platform used to install the absolute gravity measurement system; predicts the motion of the installation platform within the prediction time based on the motion information of the installation platform to obtain a prediction result; when the prediction result is less than a reference index, performs absolute gravity measurement based on the absolute gravity measurement system on the installation platform, and the reference index is used to indicate the maximum motion information of the installation platform that the absolute gravity measurement system can withstand in the current scenario to achieve the target measurement accuracy. The moving platform absolute gravity measurement fall prediction method provided in the present application predicts the motion of the installation platform in the future short period of time based on the motion data of the installation platform that has been collected, and compares it with the pre-calculated reference index, thereby helping the absolute gravity measurement system make a decision on whether to perform the measurement. Therefore, the moving platform absolute gravity measurement falling prediction method and system provided in the present application predicts the best time for falling measurement by referring to indicators and the movement information of the installation platform to ensure normal measurement. Since the influence of the movement of the installation platform at this time on the measurement accuracy is within an acceptable level for the target measurement accuracy, the influence of the violent movement of the installation platform on the gravity measurement can be reduced, thereby improving the measurement accuracy and solving the problem of traditional technology ensuring effective measurement by sacrificing measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is the schematic diagram of the laser interferometric absolute gravity measurement system in traditional technology.

[0028] Figure 2 It is a schematic diagram of the lateral disturbance occurring in the laser interferometer absolute gravity measurement system in the traditional technology.

[0029] Figure 3 This is the schematic diagram of the atomic interferometry absolute gravity measurement system in traditional technology.

[0030] Figure 4 It is a flow chart of a method for predicting the fall of a moving platform using absolute gravity measurement in one embodiment of the present application.

[0031] Figure 5 It is a schematic diagram of the installation position of the data acquisition device in one embodiment of the present application.

[0032] Figure 6 It is a flow chart of a method for predicting the fall of a moving platform using absolute gravity measurement in one embodiment of the present application.

[0033] Figure 7 It is a curve diagram showing the change of the interference peak value or interference contrast with the beam shear displacement in one embodiment of the present application.

[0034] Figure 8Schematic diagram of the displacement value of the horizontal displacement stage in one embodiment of the present application.

[0035] Fig. 9 It is a flowchart of the steps of predicting the movement of the installation platform within the prediction time according to the movement information of the installation platform and obtaining the prediction result in one embodiment of the present application.

[0036] Fig.10 It is a schematic diagram of a falling prediction device for absolute gravity measurement of a moving platform in one embodiment of the present application.

[0037] Fig.11 It is a diagram of the internal structure of a computer device according to an embodiment of the present application. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0039] In traditional technology, see Figure 1 The falling body of the laser interferometric absolute gravity measurement system is a corner cube prism. The corner cube prism is used to lift, release and receive the falling body through a falling body trolley. The Mach-Zender interferometric technique is used to measure the displacement change of the falling body during free fall. The laser interferometric absolute gravity measurement system is also called a laser interferometric absolute gravimeter. See Figure 2 , the movement of the mounting platform (base) may cause the reference prism fixed to the mounting platform to have a lateral disturbance relative to the falling prism. The distance that the falling prism moves relative to the reference prism is the lateral disturbance displacement. According to the Mach-Zender interferometry principle, the lateral disturbance displacement of the falling prism relative to the reference prism will reduce the overlap of the reference light and the measurement light, thereby reducing the interference contrast and affecting the absolute gravity measurement accuracy. This phenomenon is called the beam shearing phenomenon caused by lateral disturbance. Since the release and reception of the falling prism are achieved by a semi-enclosed falling cart, the falling cart plays a certain limiting role in the free fall process of the falling prism. Therefore, if the lateral disturbance displacement is too large, the falling prism may come into contact with the falling cart that is also accelerating downward, resulting in discontinuous measurement data or even interruption of the measurement process. This phenomenon is called the wall-hitting phenomenon caused by lateral disturbance.

[0040] See also Figure 3The falling objects of the atomic interferometric absolute gravity measurement system are cold atoms, and the matter wave interference technology is used to measure the phase changes of atoms in free fall. The atomic interferometric absolute gravity measurement system is also called the atomic interferometric absolute gravimeter. The output dynamic range of the atomic interferometric absolute gravity measurement system is small. When measuring on a moving platform, there is no unique solution for the output acceleration of the atomic interferometric absolute gravity measurement system. It is necessary to combine it with an inertial accelerometer with a large dynamic range to lock its output determination value. However, this determination value is only valid when the difference between the inertial accelerometer output and the atomic interferometric absolute gravity measurement system output acceleration is very small (generally much less than 10 -3 m / s 2 ) is the effective value. In a harsh dynamic environment, the installation platform moves violently, which can easily cause the difference between the acceleration output of the inertial accelerometer and the output of the atomic interferometric absolute gravity measurement system to become so large that it cannot be measured.

[0041] The traditional method to solve the problem of violent movement of the installation platform affecting the measurement effectiveness is mainly to reduce the impact of the movement of the installation platform on the absolute gravity measurement by reducing the falling time of the falling object. For example, the laser interferometer absolute gravimeter reduces the falling measurement time from 160ms in static state to 100ms in dynamic measurement, and the atomic interferometer absolute gravimeter reduces the emission interval period T of the Raman beam in the matter wave interference from 40ms in static state or 20ms in a small dynamic environment to 10ms in a dynamic environment.

[0042] The applicant has found that the above method ensures the effective measurement of absolute gravity by sacrificing measurement accuracy. In the actual measurement process, in order to obtain the best measurement effect, the method needs to balance the measurement accuracy and measurement effectiveness to obtain the best falling measurement time. For a constantly changing dynamic environment, it is difficult to balance the measurement accuracy and measurement effectiveness. If an adaptive method is used to determine the optimal falling measurement time corresponding to each falling measurement, it is first necessary to determine the cycle value before each measurement according to the preliminary preprocessing algorithm. Secondly, since the falling measurement time used by different measuring points is different, the single measurement accuracy of different measuring points is also different, and it is necessary to use different weights for different measuring points according to the post-processing algorithm to weighted average to obtain the final gravity measurement value. If the adaptive method is not used to obtain the falling measurement time for each time, and a unified falling measurement time is used, the shortest possible measurement time is used to ensure a high effective utilization rate of the measurement data, which will inevitably lead to a large loss of measurement accuracy.

[0043] In order to solve the above technical problems, the applicant, in one embodiment, Figure 4As shown, a falling prediction method for absolute gravity measurement of a moving platform is provided. This embodiment takes the method applied to a terminal as an example for illustration. It can be understood that the method can also be applied to a server, and can also be applied to a system including a terminal and a server, and is implemented through the interaction between the terminal and the server. In this embodiment, the method includes the following steps:

[0044] Step 400: acquiring motion information of a mounting platform for mounting an absolute gravity measurement system.

[0045] The motion information of the installation platform can be obtained by a sensor system on the installation platform. The motion information of the installation platform can be information generated during the movement of the installation platform, and can include acceleration, velocity, displacement, and the like.

[0046] Step 402: predict the movement of the installation platform within the prediction time according to the movement information of the installation platform to obtain a prediction result.

[0047] Exemplarily, the prediction time can be a falling measurement cycle. The absolute gravity measurement system releases an object in a vacuum, measures the displacement and time of the object in free fall, and performs a quadratic fit on it to obtain the gravitational acceleration. Generally, a falling time of 100ms-150ms can be selected, and the motion trajectory of the measured object within this time period can be fitted to obtain the gravitational acceleration. The selected falling time is the falling measurement cycle. The specific value of the falling measurement cycle is not specifically limited in the embodiments of the present application.

[0048] In the disclosed embodiment, the motion information of the installation platform can be used as a state variable, and the motion of the installation platform within the prediction time can be predicted by a preset prediction method to obtain a prediction result. The prediction result can be the motion information of the installation platform within the prediction time. Exemplarily, the acceleration and displacement of the installation platform can be used as state variables, and the horizontal motion acceleration and displacement of the installation platform within the prediction time can be predicted by a Kalman filter algorithm.

[0049] Step 404, when the predicted result is less than the reference index, an absolute gravity measurement is performed based on the absolute gravity measurement system on the installation platform, and the reference index is used to indicate the maximum movement information of the installation platform that the absolute gravity measurement system can withstand to achieve the target measurement accuracy.

[0050] In the embodiment of the present application, the maximum motion information is the maximum value of the motion information generated by the installation platform during the motion, such as the maximum value of displacement, velocity or acceleration. In the case where the absolute gravity measurement system has set the target measurement accuracy, the reference index can be characterized as the threshold value of the motion information of the installation platform when the measurement accuracy of the absolute gravity measurement system meets the target measurement accuracy. Exemplarily, when the displacement of the installation platform exceeds the reference index, the measurement accuracy of the absolute gravity measurement system is less than the target measurement accuracy, and when the displacement of the installation platform does not exceed the reference index, the measurement accuracy of the absolute gravity measurement system is greater than or equal to the target measurement accuracy. Therefore, when the prediction result (such as the horizontal motion displacement of the installation platform within the prediction time) is less than the reference index, the measurement result obtained by the absolute gravity measurement system for absolute gravity measurement will meet the target measurement accuracy, and at this time, the absolute gravity measurement can be performed based on the absolute gravity measurement system. In the case where the prediction result is greater than or equal to the reference index, the measurement result obtained by the absolute gravity measurement system for absolute gravity measurement will not meet the target measurement accuracy, and at this time, the absolute gravity measurement system does not perform absolute gravity measurement.

[0051] In the above-mentioned moving platform absolute gravity measurement fall prediction method, the movement of the installation platform in the short future time is predicted based on the collected movement data of the installation platform, and compared with the pre-calculated reference index, so as to help the absolute gravity measurement system make a decision on whether to perform the measurement. Therefore, the moving platform absolute gravity measurement fall prediction method provided by the present application predicts the best time for the fall measurement through the reference index and the movement information of the installation platform to ensure the normal measurement. Since the influence of the movement of the installation platform at this time on the measurement accuracy is within the acceptable level of the target measurement accuracy, the influence of the violent movement of the installation platform on the gravity measurement can be reduced, the measurement accuracy is improved, and the problem of the traditional technology ensuring the effective measurement by sacrificing the measurement accuracy is solved.

[0052] In one embodiment, in step 400, motion information of an installation platform for installing an absolute gravity measurement system is obtained, including: obtaining motion information of the installation platform based on a data acquisition device of the installation platform, the data acquisition device including at least one of an accelerometer, a gyroscope, a satellite positioning system, and a radio positioning system, and the motion information includes at least one of acceleration, velocity, and displacement.

[0053] The accelerometer may be a three-axis accelerometer. The satellite positioning system (GPS) may measure the position, speed, acceleration and even posture of the installation platform. The gyroscope may measure the angle and angular velocity of the installation platform. Figure 5As shown, multiple accelerometers, gyroscopes, and GPS antennas can be tightly connected and installed with the installation platform. The motion information of the installation platform can also include environmental data such as tides and weather, which can be reasonably matched and realized by different sensors in the data acquisition device.

[0054] It should be noted that the data acquisition device is not specifically limited in the present application. The data acquisition device may also include any instrument that can obtain the movement information of the installation platform.

[0055] In one embodiment, see Figure 6 , the falling prediction method of the moving platform absolute gravity measurement also includes:

[0056] Step 600, determining the relationship between the lateral disturbance displacement and the measurement accuracy.

[0057] In the embodiment of the present disclosure, the absolute gravity measurement system is a laser interferometer absolute gravity measurement system. Figure 2 , the movement of the mounting platform will cause the reference prism to have horizontal acceleration, while the falling prism is not subject to horizontal acceleration during free fall, so horizontal lateral disturbance of the falling prism relative to the reference prism will occur. The lateral disturbance reduces the overlap between the reference light and the measurement light that originally interfered, thereby reducing the interference contrast and the peak-to-peak value of the interference fringes, which reduces the measurement accuracy of the falling prism displacement calculated based on the interference fringes. If the lateral disturbance displacement is d, that is, the distance the falling prism moves relative to the reference prism is d, then the distance the measurement light moves relative to the reference light is 2d, which is called the beam shear displacement.

[0058] Exemplarily, a first relationship between the beam shear displacement and the interference contrast or the interference peak-to-peak value can be determined by simulation, and a second relationship between the interference contrast or the interference peak-to-peak value and the measurement accuracy can be determined by experiment. Based on the first relationship and the second relationship, the relationship between the lateral disturbance displacement and the measurement accuracy can be obtained.

[0059] Laser interferometry uses the Mach-Zender interferometry principle: the laser beam is collimated and then split into two paths by the beam splitter, one for the transmitted light (as the reference arm) and the other for the reflected light (as the measurement arm). For example, assuming that the light intensity at the cross section of the beam propagation along the z-axis is Gaussian, the collimated transmitted light and reflected light beam can be considered as Gaussian plane waves, and their electric vectors are recorded as E and E respectively. 1 , E 2 The electric vector satisfies the following formula (I) and formula (II).

[0060]

[0061]

[0062] In which, the beam propagation direction is the z-axis, and the mutually perpendicular x-axis and y-axis are defined in the plane perpendicular to the z-axis to establish the x, y, z spatial coordinate system, i is an imaginary number, and E(x, y, z) is the electric vector E 1 or E 2 , ω(z) is the spot radius at point z, A 0 is the central light amplitude at z = 0, k is the wave number, ω 0 is the beam waist radius, D is the collimated beam diameter, λ is the laser wavelength. The resultant electric vector obtained after the interference of the transmitted light and the reflected light is E. The resultant electric vector satisfies the following superposition theorem formula (III). The interference light intensity satisfies the following formula (IV).

[0063] E=E 1 +E 2 Formula (III)

[0064]

[0065] Where, I is the interference light intensity of the combined light beam after the interference of the transmitted light and the reflected light. The light intensity of the combined light beam will change with the phase difference between the two light beams, thereby obtaining the interference contrast ν. The interference contrast can characterize the light and dark contrast of the interference image. The interference contrast satisfies the following formula (V).

[0066]

[0067] Among them, I max is the maximum value of the interference intensity of the combined light beam, I min is the minimum value of the interference intensity of the combined light beam, I 1 is the intensity of the transmitted light, I 2 is the intensity of the reflected light. The peak-to-peak value of the interference is I max and I min The difference between the peak-to-peak value of interference and the interference contrast can be converted and calculated mutually, that is, the peak-to-peak value of interference and the interference contrast can characterize each other. The interference light intensity I of the combined light beam can satisfy the following formula (VI).

[0068] P=∫∫I(x,y)dxdy Formula (VI)

[0069] Where P is the laser power.

[0070] Substituting the parameters of the laser interferometric absolute gravity measurement system used in the laboratory: collimated beam diameter D = 2.06 mm, laser power P = 600 μW, laser wavelength λ = 633 nm, changing the values ​​of x and y respectively, and using the above formula to calculate the interference light intensity at different z positions (i.e., different phase differences), we can obtain the curve of the interference peak-to-peak value or interference contrast with the beam shear displacement in the x or y direction, that is, the first relationship between the beam shear displacement and the interference contrast or interference peak-to-peak value, as shown in Figure 7 shown.

[0071] For example, in Figure 7 In the variation curve shown, if the target measurement accuracy is set such that the interference contrast ratio cannot be reduced by more than 30% during measurement, the limits Δx and Δy on the shear displacement of the beam in the x and y directions can be obtained.

[0072] In the case of static measurement, the reference prism is mounted on a horizontal displacement stage, and the reference prism is moved by the horizontal displacement stage to simulate the beam shear displacement caused by the movement of the mounting platform. A series of horizontal displacement stage displacement values ​​near the maximum interference peak value are selected, and an absolute gravity measurement experiment is performed at each horizontal displacement value to obtain the measurement results, and the measurement accuracy and interference peak-to-peak value at each horizontal displacement value are recorded. According to the one-to-one measurement accuracy and interference peak-to-peak value, a curve of the change of interference peak-to-peak value with measurement accuracy is drawn, that is, the second relationship between interference contrast or interference peak-to-peak value and measurement accuracy can be obtained through experiments. In the experiment, the interference peak-to-peak value can be output by a photodetector and can be detected by an oscilloscope.

[0073] Through the first relationship and the second relationship, the interference peak-to-peak value or interference contrast can be used as an intermediate value, and the beam shear displacement is linked to the measurement accuracy one-to-one, and the change curve of the measurement accuracy and the beam shear displacement is drawn, so that the relationship between the lateral disturbance displacement and the measurement accuracy can be obtained. The lateral disturbance displacement is generally half of the beam shear displacement value, so the relationship between the lateral disturbance displacement and the measurement accuracy can be obtained. However, the above simulation method for determining the first relationship between the beam shear displacement and the interference contrast or the interference peak-to-peak value does not take into account that the beam in the actual laser interferometric absolute gravity measurement system is not a perfectly collimated beam, and does not take into account the degree of light intensity loss of the beam after passing through lenses such as lenses and prisms. Therefore, in practical applications, the relationship between the lateral disturbance displacement and the measurement accuracy can be directly determined by experiment. In the case of static measurement, the reference prism is installed on the horizontal displacement table, and the reference prism is moved by the horizontal displacement table to simulate the beam shear displacement caused by the movement of the installation platform. Select a series of horizontal displacement table displacement values ​​near the maximum interference peak-to-peak value, and perform an absolute gravity measurement experiment at each horizontal displacement table displacement value, obtain the measurement results, and record the measurement accuracy and interference peak-to-peak value at the displacement value of the horizontal displacement table. The displacement value of the horizontal displacement stage is the value of the scale on the horizontal displacement stage. Determine the displacement value of the horizontal displacement stage when the measurement accuracy is the highest, select another measurement accuracy and the displacement value of the horizontal displacement stage corresponding to it, and the difference between the displacement value of the horizontal displacement stage when the measurement accuracy is the highest and the displacement value of the horizontal displacement stage corresponding to the selected measurement accuracy is the lateral shear displacement corresponding to the selected measurement accuracy. Repeat the above steps to obtain the relationship between the lateral disturbance displacement and the measurement accuracy.

[0074] Step 602, obtaining a reference index based on the relationship between the lateral disturbance displacement and the measurement accuracy.

[0075] For example, see Figure 8 , assuming that the displacement value of the horizontal displacement stage corresponding to the highest measurement accuracy is S 0 When the target measurement accuracy is determined to be A, the corresponding displacement value of the horizontal displacement stage is S 1 and S 2 . S 1 and S 2 are the displacement values ​​S of the horizontal translation stage 0 The displacement values ​​in the left and right directions. That is, when the measurement accuracy is less than the target measurement accuracy A, according to the relationship between the lateral disturbance displacement and the measurement accuracy, the corresponding lateral disturbance displacement cannot exceed the limit value ΔS=|S 0 -S 1 |or|S 0 -S 2 The limit value ΔS is the maximum movement information (horizontal displacement) of the installation platform that the absolute gravity measurement system can withstand to achieve the target measurement accuracy A, which is the reference indicator.

[0076] After obtaining the limit value ΔS (x or y direction) of the lateral disturbance displacement under the target measurement accuracy, the best falling time is determined by judging whether the predicted result exceeds the limit value ΔS during the absolute gravity test.

[0077] For example, assuming that the installation platform has horizontal acceleration motion and pitch or roll motion at the same time, if the accelerometer and gyroscope obtain the installation platform motion acceleration a(t) and tilt angle change rate ω(t) in real time. The current time is t 0 , to determine whether it is appropriate to complete the 0.1s drop test within the next 0.5s. The horizontal displacement S(t) of the reference prism relative to the falling prism during the free fall of the falling prism can be predicted by combining a(t) and ω(t). If S(t)≤ΔS, the drop test can be performed.

[0078] It should be noted that when the actual motion state is more complex, the falling prediction method of the moving platform absolute gravity measurement can use more sensors to more accurately predict the motion state at future moments. The prediction results and reference indicators are not limited to the lateral disturbance displacement of the reference prism relative to the falling prism, but also include other motion parameters that may affect the measurement accuracy of the mobile platform, such as the inclination angle of the absolute gravity measurement system and the vertical motion acceleration. This application does not specifically limit the motion information, data acquisition device, reference indicators, etc. of the installation platform. When the reference indicator is other motion information such as acceleration or velocity, the horizontal displacement of the installation platform can be calculated by physical formulas, and the specific calculation process is not specifically limited in this application.

[0079] In addition, the absolute gravity measurement system can also be an atomic interferometry absolute gravity measurement system. The difference is that the movement of the installation platform has different effects on the atomic interferometry absolute gravity measurement system. Therefore, it is necessary to analyze the measurement principle of the atomic interferometry absolute gravity measurement system to obtain the influence of the platform movement acceleration, velocity or displacement on the measurement, so as to derive the maximum movement information of the installation platform that the absolute gravity measurement system can withstand under the premise of ensuring the target measurement accuracy, and use this as a reference indicator for the falling decision. The embodiment of the present application does not specifically limit the method for obtaining the reference indicator.

[0080] In one embodiment, see Fig. 9 In step 102, the movement of the installation platform within the prediction time is predicted according to the movement information of the installation platform to obtain a prediction result, including:

[0081] Step 900, using the movement information of the installation platform as a state variable;

[0082] Step 902: predict the movement of the installation platform within the prediction time according to the state variables and the preset prediction method to obtain the prediction result.

[0083] Exemplarily, the acceleration and displacement of the mounting platform are used as state variables, and the Kalman filter algorithm is used to predict the horizontal acceleration and displacement of the mounting platform within the prediction time. In the laser interferometric absolute gravity measurement system, since the reference prism is tightly fixed to the mounting platform, the horizontal acceleration and displacement of the mounting platform can be used as the horizontal acceleration and displacement of the reference prism. The predicted horizontal acceleration and displacement of the mounting platform are used as the prediction result. When the prediction result is less than the reference index, the absolute gravity measurement is performed based on the absolute gravity measurement system on the mounting platform.

[0084] It should be noted that the preset prediction method can be replaced by any algorithm that can realize the prediction of time series parameters, and the optimal prediction algorithm under different dynamic motion environments can be determined by evaluating and weighing the performance of the algorithm such as rapidity and accuracy. The preset prediction method can be a mathematical modeling method such as an autoregressive moving average hybrid model (ARMA), an autoregressive model (AR) or a moving average model (MA) in a statistical method, but such traditional methods have certain limitations in the face of nonlinear systems with randomness and complexity. Therefore, the preset prediction method can also adopt a prediction algorithm based on an artificial neural network, which has stronger dynamic adaptability, fast prediction speed, and is more suitable for nonlinear systems. The embodiment of the present application does not specifically limit the preset prediction method, and all algorithms that can realize the prediction function can be adopted.

[0085] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0086] The present application also provides a falling prediction system for absolute gravity measurement of a moving platform. The falling prediction system for absolute gravity measurement of a moving platform includes an absolute gravity measurement system, a mounting platform and a measuring device. Among them, the absolute gravity measurement system is installed on the platform. The measuring device is used to obtain the motion information of the mounting platform, and predict the motion of the mounting platform within the prediction time according to the motion information of the mounting platform to obtain a prediction result. When the prediction result is less than the reference index, the absolute gravity measurement system is used to perform absolute gravity measurement. The reference index is used to indicate the maximum motion information of the mounting platform that the absolute gravity measurement system can withstand in order to achieve the target measurement accuracy.

[0087] The falling prediction system for absolute gravity measurement of a moving platform provided by the present application, the measuring device obtains the motion information of the installation platform. The measuring device predicts the movement of the installation platform in the short future based on the collected motion data of the installation platform, and compares it with the reference index calculated in advance, so as to help the absolute gravity measurement system make a decision on whether to perform the measurement. Therefore, the falling prediction system for absolute gravity measurement of a moving platform provided by the present application ensures the normal measurement by predicting the best time for the falling measurement, which solves the problem that the traditional technology ensures the effective measurement by sacrificing the measurement accuracy.

[0088] The implementation solution to the problem provided by the falling prediction system of absolute gravity measurement of a moving platform in the embodiment of the present application can be described in accordance with the falling prediction method of absolute gravity measurement of a moving platform in the aforementioned embodiment, and the embodiment of the present application will not be repeated here.

[0089] In one embodiment, the measuring device is further used to determine the relationship between the lateral disturbance displacement and the measurement accuracy, and obtain a reference index based on the relationship between the lateral disturbance displacement and the measurement accuracy.

[0090] Based on the same inventive concept, the embodiment of the present application also provides a moving platform absolute gravity measurement fall prediction device for implementing the moving platform absolute gravity measurement fall prediction method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations of one or more moving platform absolute gravity measurement fall prediction device embodiments provided below can refer to the limitations of the moving platform absolute gravity measurement fall prediction method above, and will not be repeated here.

[0091] In one embodiment, participating Fig.10 , a falling prediction device 800 for absolute gravity measurement of a moving platform is provided, comprising: a data acquisition module 801, a data processing module 802, a judgment module 803 and a measurement module 804, wherein:

[0092] The data acquisition module 801 is used to obtain the movement information of the installation platform.

[0093] The data processing module 802 is used to predict the movement of the installation platform within the prediction time according to the movement information of the installation platform to obtain a prediction result.

[0094] The judgment module 803 is used to judge whether the prediction result is less than the reference index.

[0095] The measurement module 804 is used to perform absolute gravity measurement when the predicted result is less than the reference index.

[0096] The above-mentioned falling prediction device for absolute gravity measurement of the moving platform ensures the normal measurement by predicting the best time for falling measurement, which solves the problem that the traditional technology ensures the effective measurement by sacrificing the measurement accuracy.

[0097] In one embodiment, the data acquisition module 801 is also used to obtain motion information of the installation platform based on a data acquisition device of the installation platform, the data acquisition device includes at least one of an accelerometer, a gyroscope, a satellite positioning system, and a radio positioning system, and the motion information includes at least one of acceleration, velocity and displacement.

[0098] In one embodiment, the falling prediction device 800 for absolute gravity measurement of a moving platform further includes a data analysis module for determining the relationship between the lateral disturbance displacement and the measurement accuracy, and obtaining a reference index based on the relationship between the lateral disturbance displacement and the measurement accuracy.

[0099] In one embodiment, the data processing module 802 is further configured to use the movement information of the installation platform as a state variable; and predict the movement of the installation platform within the prediction time according to the state variable and a preset prediction method to obtain a prediction result.

[0100] Each module in the above-mentioned falling prediction device 800 for absolute gravity measurement of a moving platform can be implemented in whole or in part by software, hardware, or a combination thereof. Each of the above-mentioned modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to each of the above modules.

[0101] In one embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as follows: Fig.11 As shown. The computer device includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a method for predicting the fall of a moving platform absolute gravity measurement is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a button, trackball or touchpad set on the computer device housing, or an external keyboard, touchpad or mouse, etc.

[0102] Those skilled in the art will understand that Fig.11 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0103] In one embodiment, a computer device is provided, which includes a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the steps of the method for predicting the fall of a moving platform by absolute gravity measurement in any of the above embodiments are implemented.

[0104] In one embodiment, a computer-readable storage medium is provided, wherein a computer program is stored thereon, and when the computer program is executed by a processor, the steps of the method for predicting the fall of a moving platform by measuring absolute gravity in any of the above embodiments are implemented.

[0105] In one embodiment, a computer program product is provided, including a computer program, which, when executed by a processor, implements the steps of the method for predicting the fall of a moving platform by absolute gravity measurement in any of the above embodiments.

[0106] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0107] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0108] The above-described embodiments only express several implementation methods of the present application, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present application, which all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the attached claims.

Claims

1. A falling prediction method for absolute gravity measurement of a moving platform, characterized in that: The method comprises: Obtaining motion information of a mounting platform for mounting an absolute gravity measurement system; Predicting the movement of the installation platform within a prediction time according to the movement information of the installation platform to obtain a prediction result; In the case where the predicted result is less than a reference index, performing absolute gravity measurement based on the absolute gravity measurement system on the installation platform, the reference index being used to indicate the maximum movement information of the installation platform that the absolute gravity measurement system can withstand in order to achieve a target measurement accuracy; The method further includes: determining a first relationship between the beam shear displacement and the interference contrast or the interference peak-to-peak value through simulation; determining a second relationship between the interference contrast or the interference peak-to-peak value and the measurement accuracy through experiments; obtaining a relationship between the lateral disturbance displacement and the measurement accuracy based on the first relationship and the second relationship; and obtaining the reference index based on the relationship between the lateral disturbance displacement and the measurement accuracy.

2. The falling prediction method of the moving platform absolute gravity measurement according to claim 1, characterized in that: The step of obtaining the motion information of the installation platform for installing the absolute gravity measurement system comprises: The motion information of the installation platform is acquired based on a data acquisition device of the installation platform, wherein the data acquisition device includes at least one of an accelerometer, a gyroscope, a satellite positioning system, and a radio positioning system, and the motion information includes at least one of acceleration, velocity, and displacement.

3. The falling prediction method of the moving platform absolute gravity measurement according to claim 1, characterized in that: The step of predicting the movement of the installation platform within the prediction time according to the movement information of the installation platform to obtain the prediction result includes: Using the motion information of the installation platform as a state variable; The movement of the installation platform within the prediction time is predicted according to the state variables and the preset prediction method to obtain a prediction result.

4. A falling prediction system for absolute gravity measurement of a moving platform, characterized in that: include: Absolute gravity measurement system, mounting platform, measuring device, wherein the absolute gravity measurement system is mounted on the mounting platform, The measuring device is used to obtain the motion information of the installation platform, and predict the motion of the installation platform within the prediction time according to the motion information of the installation platform to obtain a prediction result; In the case where the predicted result is less than the reference index, the absolute gravity measurement system is used to perform absolute gravity measurement, and the reference index is used to indicate the maximum movement information of the installation platform that the absolute gravity measurement system can withstand in order to achieve the target measurement accuracy; The measuring device is also used to determine a first relationship between the beam shear displacement and the interference contrast or the interference peak-to-peak value through simulation; determine a second relationship between the interference contrast or the interference peak-to-peak value and the measurement accuracy through experiments; and obtain a relationship between the lateral disturbance displacement and the measurement accuracy based on the first relationship and the second relationship; Based on the relationship between the lateral disturbance displacement and the measurement accuracy, the reference index is obtained.

5. A falling prediction device for absolute gravity measurement of a moving platform, characterized in that: include: A data acquisition module, used to obtain the motion information of the installation platform; A data processing module, used to predict the movement of the installation platform within a prediction time according to the movement information of the installation platform to obtain a prediction result; A judgment module, used to judge whether the prediction result is less than a reference index; A measurement module, used for performing absolute gravity measurement when the predicted result is less than the reference index; Among them, the device also includes a data analysis module, which is used to determine the first relationship between the beam shear displacement and the interference contrast or the interference peak-to-peak value through simulation; determine the second relationship between the interference contrast or the interference peak-to-peak value and the measurement accuracy through experiments; based on the first relationship and the second relationship, obtain the relationship between the lateral disturbance displacement and the measurement accuracy; based on the relationship between the lateral disturbance displacement and the measurement accuracy, obtain the reference index.

6. The falling prediction device for absolute gravity measurement of a moving platform as claimed in claim 5, characterized in that: The data acquisition module is also used to obtain motion information of the installation platform based on a data acquisition device of the installation platform, wherein the data acquisition device includes at least one of an accelerometer, a gyroscope, a satellite positioning system, and a radio positioning system, and the motion information includes at least one of acceleration, velocity, and displacement.

7. The falling prediction device for absolute gravity measurement of a moving platform as claimed in claim 5, characterized in that: The data processing module is also used to use the movement information of the installation platform as a state variable; and predict the movement of the installation platform within a prediction time according to the state variable and a preset prediction method to obtain a prediction result.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 3 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 3 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 3 are implemented.

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