High-precision testing method for resolution of gravity sensor

Abstract

The present application relates to a kind of high-precision test methods of gravity sensor resolution, steps are as follows: 1 gravity sensor is fixed on the upper end surface of the static base of measurement site according to working posture, so that sensitive axis is perpendicular to local geographic level;2 the measured gravity sensor is converted to gravity measurement state, starts to record the gravity measurement value of the output of measured gravity sensor, records the average value g of the output data of measured gravity sensor in 1 minute t , synchronous record test time, longitude, latitude, form test data sequence, form the data sequence consisting of g t , T t , Lon t , Lat t in time sequence arrangement;3 according to the longitude, latitude, data recording time recorded in the sequence of gravity sensor output data, calculate the calculated change value sequence of local solid tide influence, and calculate the solid tide correction value g e ;4 combine g t With g e , obtain the resolution of measured gravity sensor.The present application is not cross-coupled in the test process, and is closer to the normal working state of gravity sensor.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of resolution measurement of gravity sensor, and particularly relates to a high-precision test method for resolution of gravity sensor. BACKGROUND

[0002] The resolution index of gravity sensor is an important performance index of gravity sensor. Limited by the manufacturing limit of the test device, the traditional test method is only applicable to resolution test of 1x10 -6 g precision accelerometer. The resolution test of 1x10 -9 g resolution requires a new test method.

[0003] The traditional method for testing gravity sensor is to change the attitude of the gravity sensor in the gravity field, that is, to adjust the projection component of the local gravity vector on the sensitive axis of the gravity sensor, so as to achieve the purpose of testing the sensitivity of the gravity sensor. The existing resolution test of gravity sensing device is to place the gravity sensing device on a high-resolution single-axis or double-axis positioning rotating device, such as a high-precision indexing head or a high-precision rotary table, to drive the gravity sensing device to rotate around one axis or two orthogonal axes in a specific rule, to control the pointing direction of the sensitive axis of the gravity sensing device in the gravity field, so that the gravity vector pointing to the sensitive axis of the gravity sensing device presents a specific rule of angle sequence, to achieve the purpose of controlling the acceleration input of the gravity sensing device, and to test the resolution of the gravity sensing device. This method is limited by the manufacturing limit of the angle given device, and cannot accurately give a small gravity given value. Moreover, the method of changing the gravity sensor input given by changing the attitude of the gravity sensor will also bring additional errors to the sensitivity test due to the cross coupling effect.

[0004] For example, the invention patent 201210303109.3 (CN 102788887 B) adopts a double-axis rotary table method, installs the accelerometer horizontally on the double-axis rotary table, uses the inclination angle of the first axis of the double-axis rotary table, and rotates the second axis; the invention patent 201510369539.9 (CN 104914485 B) installs the measured accelerometer on a precision single-axis rotating device, and rotates the precision rotating device on a horizontal plane to adjust the pointing direction of the sensitive axis of the accelerometer; the invention patent 201710295273.7 (CN 106990263 B) places the measured accelerometer on the rotating table of a centrifuge, points the sensitive axis of the accelerometer to the normal direction of the rotating plane of the centrifuge, adjusts the rotating speed of the centrifuge, and uses the centrifugal acceleration as the excitation input to measure the resolution of the accelerometer. The above several invention patents all change the pointing direction of the sensitive axis of the gravity sensor in the gravity field by mechanical angle, and change the gravity sensor input given for testing the gravity sensor or the accelerometer. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-precision testing method for the resolution of a gravity sensor that does not employ mechanical devices, does not change the attitude of the gravity sensor under test, and avoids errors caused by mechanical angle setting devices.

[0006] The above-mentioned objective of the present invention is achieved through the following technical solution:

[0007] A high-precision testing method for the resolution of a gravity sensor, characterized by comprising the following steps:

[0008] Step 1: Fix the gravity sensor on the upper surface of the static base at the measurement location in its working posture, so that the sensing axis is perpendicular to the local geographical horizontal plane; the measurement location has at least longitude, latitude and height data;

[0009] Step 2: Switch the gravity sensor under test to gravity measurement mode, start recording the gravity measurement value output by the gravity sensor under test, and record the average value g of the data at 1-minute time intervals. t Synchronously record test time T t Longitude Lon t Latitude t This forms a test data sequence;

[0010] Step 3: Based on the longitude, latitude, and data acquisition time recorded in the sequence of data output from the gravity sensor, calculate the sequence of calculated changes in the local solid tide influence. The calculation interval is 1 minute. Calculate the solid tide correction value g according to the solid tide correction formula listed in the relevant national and provincial standards. e ;

[0011] Step 4: Combine the data recorded in Step 2 with the data calculated in Step 3 to obtain the resolution of the gravity sensor under test.

[0012] Furthermore: In step 1, the test site is selected in an environment with stable foundation and far away from strong electric and magnetic interference.

[0013] Further: In step 1, the gravity sensor is placed in the heat-insulating shell and the temperature is controlled by the temperature control system; before the gravity state measurement, the gravity sensor under test is fully preheated to ensure that the test process is under stable temperature conditions, and the preheating time is not less than the corresponding requirements in the specifications of the gravity sensor under test.

[0014] Furthermore: In step 2, the admission period is 30 days.

[0015] Furthermore, step 4 specifically includes the following steps:

[0016] 4.1. The gravity sensor test data g collected in step 2 t Multiply by the scale k to calculate the corresponding gravitational value g. c That is, g c =g t ×k;

[0017] 4.2. The gravity value g calculated in 4.1 is... c The solid tide data g calculated in step 3 e Unify to the same unit of calculation, mGal;

[0018] 4.3 The gravity value g of the gravity sensor obtained in 4.2 is... c In the process of removing linear drift and gravity constant, the AC component g in the gravity sensor data is obtained. a ;

[0019] 4.4 The AC component g in the gravity sensor data obtained in 4.3 c The gravitational change caused by solid tides within the same time period is taken as a given value g. e Take the absolute value of the quotient, and select the data points whose quotient is less than 50%, i.e., |g c / g e If |<0.5, take the corresponding g of solid tide. e The absolute value of the maximum value is used as the sensitivity value, i.e., the resolution r = |maximum(g) e | |gc / ge|<0.5) |), thus obtaining the resolution of the gravity sensor being measured.

[0020] The advantages and positive effects of this invention are as follows:

[0021] 1. The testing conditions of this invention are simple, requiring only the gravity sensor to be fixedly installed on a static base, without any mechanical reference device;

[0022] The testing process is not limited by errors or accuracy caused by mechanical constraints.

[0023] 2. The limiting resolution given by this invention is increased to 1×10⁻⁶. -9 g;

[0024] 3. This invention has no cross-coupling effects during testing.

[0025] In summary, this invention uses solid tides for gravity sensitivity measurement. The gravity sensor under test is fixedly installed on a static base in its working posture, without the need for mechanical devices to change its posture. Through solid tide calculations, a value of 10 can be given. -9The g-gravity change is used to compare with the measured gravity data to determine the sensitivity of the gravity sensor. This solves the problems of attitude error and cross-coupling error of the given device in the traditional test method of tumbling test of the gravity sensor in the gravity field. Attached Figure Description

[0026] Figure 1 Block diagram of the gravity sensor resolution testing system of this invention. Detailed Implementation

[0027] The structure of the present invention will be further described below with reference to the accompanying drawings and embodiments. It should be noted that these embodiments are descriptive and not limiting.

[0028] This invention proposes a method for testing the resolution of a gravity sensor, applicable to sensors with a resolution and sensitivity of 1×10⁻⁶. -9 The g-axis gravity sensor test and the vertical accelerometer resolution test when the sensing axis is perpendicular to the local geographical horizontal plane during operation are also included. The system block diagram is shown below. Figure 1 As shown.

[0029] The implementation steps include the following:

[0030] Step 1: Fix the gravity sensor. Specifically, select a static base and place it at the test location. The test location should have at least longitude, latitude, and altitude data. The test location should preferably be in a stable environment, away from strong electrical and magnetic interference. In this invention, the static base is a marble base, and the upper surface of the static base serves as the sensor mounting surface. The flatness of the mounting surface must reach level 0. Multiple adjustable feet are fixedly installed on the upper end of the static base. By adjusting the feet, the upper surface of the static base is made parallel to the local horizontal plane. Then, the gravity sensor to be tested is fixedly installed on the upper surface of the static base in its working posture, so that the sensing axis is perpendicular to the local horizontal plane. Preferably, an insulated shell is provided outside the gravity sensor to be tested, and the temperature is controlled by a temperature control system. The gravity sensor to be tested is fully preheated to ensure that the test process is under stable temperature conditions. The preheating time is not less than the corresponding requirements in the specifications of the gravity sensor to be tested. In this invention, the preheating time is 48 hours.

[0031] Step 2: Switch the gravity sensor under test to gravity measurement mode, start recording the gravity measurement value output by the gravity sensor under test, and record the average value g of the output data of the gravity sensor under test over 1 minute. t The recording interval is 1 minute, and the test time T is recorded synchronously. t Longitude L t Latitude La t This forms a test data sequence, resulting in a sequence of data arranged in chronological order by g. t T t Lt La t The data sequence is composed of [data]. Considering the periodicity of solid tide changes, the testing period during the implementation of this invention is 30 days. Because solid tides are natural, stable, and minute influences on the Earth's gravitational field caused by the movement of near-Earth celestial bodies such as the Sun and Moon, the small variation cycle of solid tides is about 25 hours, and the large variation cycle is 30 days. The 30-day testing period can fully reflect the entire process of the gravitational periodic changes generated by solid tides.

[0032] Step 3: Based on the longitude, latitude, and data acquisition time recorded in the sequence of data output from the gravity sensor, calculate the sequence of calculated changes in the local solid tide influence. The calculation interval is 1 minute. Calculate the solid tide correction value g according to the solid tide correction formula listed in the relevant national and provincial standards. e ;

[0033] Step 4: Combining the data recorded in Step 2 with the data calculated in Step 3, the resolution of the measured gravity sensor is obtained, specifically:

[0034] 4.1. The gravity sensor test data g collected in step 2 t Multiply by the scale k to calculate the corresponding gravitational value g. c That is, g c =g t ×k;

[0035] 4.2. The gravity value g calculated in 4.1 is... c The solid tide data g calculated in step 3 e Unify to the same unit of calculation, mGal;

[0036] 4.3 The gravity value g of the gravity sensor obtained in 4.2 is... c In the process of removing linear drift and gravity constant, the AC component g in the gravity sensor data is obtained. a ;

[0037] 4.4 The AC component g in the gravity sensor data a The gravitational change caused by solid tides within the same time period is taken as a given value g. e Take the absolute value of the quotient, and select the data points whose quotient is less than 50%, i.e., |g c / g e If |<0.5, take the corresponding g of solid tide. e The absolute value of the maximum value is used as the sensitivity value, i.e., the resolution r = |maximum(g) e | |ga / ge|<0.5) |), thus obtaining the resolution of the gravity sensor being measured.

[0038] In summary, the specific implementation process of this gravity sensor resolution measurement is as follows:

[0039] 1. Install the gravity sensor according to step 1;

[0040] 2. Following step 2, record the average value (g) of the output data of the gravity sensor being tested over one minute. t (n), where n is a positive integer sequence number arranged by time, with one-minute intervals, combining the time, longitude, and latitude at the time of recording, and arranged in chronological order n; in the form of {g t (1), T t (1), Lon t (1), Lat t (1)};{g t (2), T t (2), Lon t (2), Lat t (2)};......;{g t (n), T t (n), Lon t (n), Lat t (n)};

[0041] 3. The gravity sensor data g collected in step 2 t Multiplying (n) by the scale k gives the gravitational value, g. c (n)=g t (n)×k; the data sequence is of the form {g c (1), T t (1), Lon t (1), Lat t (1)};{g c (2), T t (2), Lon t (2), Lat t (2)};......;{g c (n), T t (n), Lon t (n), Lat t (n)};

[0042] 4. Following step 3, place T t (n), Lon t (n), Lat t (n) is used as a calculation parameter to calculate the solid tidal compensation value g according to relevant standards. e , forming a data sequence {g c (n), g e (n)}, that is, {g c (1), g e(1)};{g c (2), g e (2)};......{g c (n), g e (n)};

[0043] 5. Remove the linear drift and gravity constant from the data sequence gc obtained in step 2 to obtain the AC component g in the gravity sensor data. a ; Forming a data sequence {g a (n), g e (n)}, that is, {g a (1), g e (1)};{g a (2), g e (2)};......{g c (n), g e (n)};

[0044] 6. Take the change in gravitational force generated by solid tides within the same time period as a given value g. e After taking the absolute value of the quotient, the above absolute value {|g} is formed. a / g e |}, forming a data sequence {|g a (1) / g e (1)|};{|g a (2) / g e (2)|};......{|g a (n) / g e (n)|};

[0045] 7. Find the data in the data sequence from step 6 whose values ​​are less than 50%, and find {|g a / g e The maximum value in |} {|g a (max) / g e (max)|} corresponds to the solid tidal value g in the data sequence. e (max({|g a (max) / g e (max)|})), to obtain the sensitivity resolution value r of the gravity sensor under test, that is, r=|maximum(g e | |ga / ge|<0.5) |).

[0046] Although embodiments and drawings of the present invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, alterations and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A high-precision testing method for the resolution of a gravity sensor, characterized in that, Includes the following steps: Step 1: Fix the gravity sensor to the upper surface of the static base at the measurement location in its working posture, so that the sensing axis is perpendicular to the local geographical horizontal plane; the measurement location has longitude, latitude and altitude data; Step 2: Switch the gravity sensor under test to gravity measurement mode, start recording the gravity measurement value output by the gravity sensor under test, and record the average value g of the output data of the gravity sensor under test over 1 minute. t The recording interval is 1 minute, and the test time T is recorded synchronously. t Longitude Lon t Latitude t This forms a test data sequence, resulting in a sequence of data arranged in chronological order by g. t T t Lon t Lat t The data sequence that makes up the data; Step 3: Based on the longitude, latitude, and data acquisition time recorded in the sequence of data output from the gravity sensor, calculate the sequence of calculated changes in the local solid tide influence. The calculation interval is 1 minute. Calculate the solid tide correction value g according to the solid tide correction formula listed in the relevant national and provincial standards. e ; Step 4: Combine the data recorded in Step 2 with the data g calculated in Step 3. e The resolution of the gravity sensor under test is obtained through the following steps: 4.

1. The gravity sensor test data g collected in step 2 t Multiply by the scale k to calculate the corresponding gravitational value g. c That is, g c =g t ×k; 4.

2. The gravity value g calculated in 4.1 is... c The solid tide data g calculated in step 3 e Unify to the same unit of calculation, mGal; 4.

3. The gravity value g of the gravity sensor obtained in 4.2 is... c In the process of removing linear drift and gravity constant, the AC component g in the gravity sensor data is obtained. a ; 4.

4. The AC component g in the gravity sensor data obtained in 4.3 a The gravitational change caused by solid tides within the same time period is taken as a given value g. e Take the absolute value of the quotient, and select the data points whose quotient is less than 50%, i.e., |g a / g e If |<0.5, take the corresponding g of solid tide. e The absolute value of the maximum value is used as the sensitivity value, i.e., the resolution r = |maximum(g) e | |ga / ge|<0.5 )|, thus obtaining the resolution of the gravity sensor being measured.

2. The high-precision testing method for the resolution of a gravity sensor according to claim 1, characterized in that: In step 1, the test site is selected in an environment with stable foundation and far away from strong electric and magnetic interference.

3. The high-precision testing method for the resolution of a gravity sensor according to claim 1, characterized in that: In step 1, the gravity sensor is placed in the heat-insulating shell and the temperature is controlled by the temperature control system. Before the gravity state measurement, the gravity sensor under test is fully preheated to ensure that the test process is under stable temperature conditions. The preheating time is not less than the corresponding requirements in the specifications of the gravity sensor under test.

4. The high-precision testing method for the resolution of a gravity sensor according to claim 1, characterized in that: In step 2, the admission period is 30 days.

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