Strapdown dynamic gravity measurement method and device for mixed surface and underwater operations

Abstract

The present application relates to a strapdown dynamic gravity measurement method and device for mixed surface and underwater operations. The method comprises: determining the current state of a gravimeter through an autonomous detection system during navigation, and constructing a surface or underwater strapdown dynamic gravity measurement system based on the determination result; performing gravity measurement using the strapdown dynamic gravity measurement system, and calculating raw gravity anomaly values ​​based on high-precision velocity, position, and attitude information; filtering using a low-pass filter to obtain effective gravity anomaly results; constructing a celestial accelerometer drift model for the current voyage based on a segment of initial celestial relative force and a segment of final celestial relative force; and calibrating the effective gravity anomaly results using the initial celestial relative force, the celestial accelerometer drift model, and the gravity value of the gravimeter's onshore reference point to obtain the final gravity measurement result. This method can realize strapdown dynamic gravity measurement for mixed surface / underwater operations.

Description

Technical Field

[0001] The present application relates to the field of gravity measurement technology, and in particular to a strapdown dynamic gravity measurement method and device for mixed surface and underwater operations. Background Art

[0002] The ocean gravity field not only plays an extremely important role in the research of earth science and related disciplines, but also has a huge impact on the combat effectiveness of long-range strategic weapons and equipment. The precise measurement of the ocean gravity field has significant economic benefits and scientific research and military application value. It can be used in marine geographical environment construction, future naval operations and marine resource exploration.

[0003] Currently, the means of obtaining high-precision global ocean gravity data are shipborne gravity measurements and underwater dynamic gravity measurements. As a key component of ocean exploration equipment, strapdown dynamic gravity measurement systems for mixed surface / underwater operations can accurately measure both surface and underwater gravity field information and construct global ocean gravity field models. Existing literature describes underwater dynamic gravimeters and shipborne gravimeters as two separate instruments. Shipborne gravimeters measure only surface gravity, while underwater dynamic gravimeters measure only underwater gravity. Furthermore, shipborne gravity data processing methods are separate from underwater gravity data processing methods. No method exists for achieving mixed surface / underwater strapdown dynamic gravity measurement. Summary of the Invention

[0004] Based on this, it is necessary to provide a strapdown dynamic gravity measurement method, device, computer equipment and storage medium for surface and underwater mixed operations that can realize strapdown dynamic gravity measurement of surface / underwater mixed operations to address the above technical problems.

[0005] A strapdown dynamic gravity measurement method for mixed surface and underwater operations, the method comprising:

[0006] Obtain the gravity value of the shore reference point of the gravimeter;

[0007] The celestial accelerometer before sailing is subjected to static data collection and noise filtering based on the gravimeter to obtain an initial celestial specific force.

[0008] During navigation, the current status of the gravimeter is determined by the autonomous detection system, and a strapdown dynamic gravity measurement system is constructed on the surface or underwater based on the determination results;

[0009] Use a strapdown dynamic gravity measurement system to measure gravity and obtain high-precision speed, position and attitude information;

[0010] Calculate the original gravity anomaly value based on high-precision speed, position and attitude information;

[0011] The original gravity anomaly value is filtered using a low-pass filter to obtain the effective gravity anomaly result;

[0012] The static data of the celestial accelerometer after the voyage is collected using a gravimeter and filtered to obtain a final celestial relative force. The celestial accelerometer drift model for the current voyage is constructed based on the initial celestial relative force and the final celestial relative force.

[0013] The effective gravity anomaly results are calibrated using an initial celestial specific force, the celestial accelerometer drift model, and the gravity value of the gravimeter's onshore reference point to obtain the final gravity measurement results.

[0014] In one embodiment, during navigation, the current state of a gravimeter is determined by an autonomous detection system, and a surface or underwater strapdown gravity measurement system is constructed based on the determination result, including:

[0015] During navigation, the threshold of the depth gauge is pre-set to 1.1. If the pressure value of the depth gauge P DG ≥1.1, and the number of satellites received by the satellite receiver N is less than 4, the gravimeter is judged to be underwater;

[0016] If the pressure value of the depth gauge is P DG <1.1, or the number of satellites received by the satellite receiver N ≥ 4, the gravimeter is judged to be on the water surface.

[0017] In one embodiment, when the gravimeter is detected on the water surface, a strapdown dynamic gravity measurement system of the water surface is constructed using the gravimeter as the main navigation system and GNSS as the observation quantity;

[0018] When the gravimeter is detected underwater, the Doppler velocimeter bottom height output Alt is judged. If Alt = 0, an underwater strapdown dynamic gravity measurement system is constructed with the gravimeter as the main navigation system, the horizontal position of the ultra-short baseline underwater positioning system, and the depth of the depth gauge as the observation quantities; if Alt ≠ 0, an underwater strapdown dynamic gravity measurement system is constructed with the gravimeter as the main navigation system, the speed of the Doppler velocimeter, the horizontal position of the ultra-short baseline underwater positioning system, and the depth of the depth gauge as the observation quantities.

[0019] In one embodiment, the raw gravity anomaly value is obtained by calculating based on high-precision velocity, position, and attitude information, including:

[0020] When the gravimeter is on the water surface, the original gravity anomaly value is calculated based on the high-precision speed, position and attitude information.

[0021]

[0022] Among them, f U V is the force of the sky; E、V N East speed and north speed respectively; R N 、R M are the radii of the meridian and the celestial circle respectively; L is the geographic latitude; h is the height / depth; γ is the normal gravity value related to the latitude; ω is the angular velocity of the Earth's rotation.

[0023] In one embodiment, when the gravimeter is underwater, the original gravity anomaly value is calculated based on the high-precision speed, position and attitude information.

[0024]

[0025] Among them, γ w Correction for underwater gravity gradient.

[0026] In one embodiment, constructing a celestial accelerometer drift model for the current voyage based on a segment of initial celestial specific force and a segment of final celestial specific force includes:

[0027] The celestial accelerometer drift model of the current voyage is constructed based on the initial celestial relative force and the final celestial relative force:

[0028] Δ=a0+a1(t-t0)+a2(t-t0) 2

[0029]

[0030] Where Δ is the gravimeter celestial accelerometer drift; a0, a1 and a2 are the parameters of the gravimeter celestial accelerometer long-term drift model; t is the time point of the survey line, f s0 、f s1 、f s2 …f sn All represent any initial celestial relative force in a segment of initial celestial relative forces, t s0 , t s1 , t s2 …t sn represents f s0 、f s1 、f s2 …f sn The corresponding test time, t0 represents the starting time, f0 represents the celestial force at the starting time t0, f e0 、f e1 、f e2 …f en Indicates any final azimuth ratio in a segment of final azimuth ratio, t e0 , t e1 , t e2 …t en represents f e0 、f e1、f e2 …f en The corresponding test time.

[0031] In one embodiment, the effective gravity anomaly result is calibrated using an initial celestial specific force, a celestial accelerometer drift model, and a gravity value of an onshore reference point of a gravimeter to obtain a final gravity measurement result, including:

[0032] The effective gravity anomaly result is calibrated using an initial celestial specific force and celestial accelerometer drift model, and the final gravity measurement result is: in, Indicates that the static celestial force measurement value is obtained by averaging the initial celestial force, g b Indicates the gravity value of the shore reference point of the gravimeter.

[0033] A strapdown dynamic gravity measuring device for mixed surface and underwater operations, comprising:

[0034] An initial celestial force detection module is used to obtain the gravity value of the shore reference point of the gravimeter. The celestial accelerometer before sailing is statically collected and noise filtered based on the gravimeter to obtain an initial celestial force.

[0035] The gravimeter status detection module is used to determine the current status of the gravimeter through an autonomous detection system during navigation, and to build a surface or underwater strapdown dynamic gravity measurement system based on the judgment results;

[0036] The gravity measurement module is used to measure gravity using a strapdown dynamic gravity measurement system to obtain high-precision speed, position, and attitude information; and to calculate the original gravity anomaly value based on the high-precision speed, position, and attitude information;

[0037] The module for constructing a celestial accelerometer drift model is used to filter the original gravity anomaly values ​​using a low-pass filter to obtain effective gravity anomaly results. The module uses a gravimeter to collect static data of the celestial accelerometer after the voyage and filters it to obtain a section of final celestial relative force. The module then constructs a celestial accelerometer drift model for the current voyage based on the initial celestial relative force and the final celestial relative force.

[0038] The gravity anomaly result calibration module is used to calibrate the effective gravity anomaly result using an initial celestial specific force, a celestial accelerometer drift model, and the gravity value of the gravimeter's onshore reference point to obtain the final gravity measurement result.

[0039] The strapdown dynamic gravity measurement method and device for mixed surface and underwater operations first obtains the gravity value of the shore reference point of the gravimeter; static data collection and noise filtering are performed on the celestial accelerometer before sailing based on the gravimeter to obtain an initial celestial specific force; during the sailing process, the current state of the gravimeter is judged by the autonomous detection system, and a surface or underwater strapdown dynamic gravity measurement system is constructed based on the judgment result; gravity measurement is performed using the strapdown dynamic gravity measurement system to obtain high-precision speed, position and attitude information; and the high-precision speed, position and attitude information are used to determine the current state of the gravimeter. The original gravity anomaly value is calculated based on the initial and final celestial relative forces. The original gravity anomaly value is filtered using a low-pass filter to obtain the effective gravity anomaly result. The static data of the celestial accelerometer after the voyage is collected using the gravimeter and filtered to obtain a section of final celestial relative force. The celestial accelerometer drift model for the current voyage is constructed based on the initial and final celestial relative forces. The effective gravity anomaly result is calibrated using the initial celestial relative force, the celestial accelerometer drift model, and the gravity value of the gravimeter's onshore reference point to obtain the final gravity measurement result. The present application performs gravity measurement by constructing a surface or underwater strapdown dynamic gravity measurement system in real time based on the current state of a gravimeter during navigation, and constructs a celestial accelerometer drift model using an initial celestial relative force before navigation and a final celestial relative force after navigation. The application also calibrates effective gravity anomaly results using the initial celestial relative force, the celestial accelerometer drift model, and the gravity value of the gravimeter's onshore reference point. This application not only enables dynamic gravity measurement on the surface and underwater, but also has simple operation, easy execution, and strong versatility, and improves the accuracy of gravity measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a diagram showing an application scenario of strapdown dynamic gravity measurement for mixed surface and underwater operations in one embodiment;

[0041] Figure 2 The present invention is a structural block diagram of a strapdown dynamic gravity measurement device for surface and underwater mixed operations in one embodiment. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0043] In one embodiment, Figure 1 As shown, a strapdown dynamic gravity measurement method for surface and underwater mixed operations is provided, comprising the following steps:

[0044] Step 102: Obtain the gravity value of the shore reference point of the gravimeter; perform static data collection and noise filtering on the celestial accelerometer before sailing based on the gravimeter to obtain an initial celestial specific force.

[0045] Before going out to sea, the gravimeter collects static data of the celestial accelerometer for at least 24 hours at the dock, and low-pass filters are used to eliminate high-frequency noise to obtain an effective initial celestial relative force. An initial celestial relative force represents the collection of multiple initial celestial relative forces obtained during static data collection over a continuous period of time. The gravimeter is statically aligned at the dock to determine the initial attitude, velocity, and gravity value of the onshore reference point, which is used for subsequent calibration of abnormal gravity measurement results to improve the accuracy of gravity measurements.

[0046] Step 104 , during navigation, the current state of the gravimeter is determined by the autonomous detection system, and a strapdown dynamic gravity measurement system on the surface or underwater is constructed according to the determination result.

[0047] During navigation, the threshold of the depth gauge is pre-set to 1.1. If the pressure value of the depth gauge P DG ≥1.1, and the number of satellites received by the satellite receiver N<4, it is judged that the gravimeter is underwater; if the pressure value of the depth gauge P DG <1.1, or the number of satellites received by the satellite receiver N ≥ 4, the gravimeter is judged to be on the water surface.

[0048] When the gravimeter is detected on the water surface, a strapdown dynamic gravity measurement system is constructed on the water surface using the gravimeter as the primary navigation system and GNSS as the observation quantity. When the gravimeter is detected underwater, since the Doppler velocimeter generally has a range of 0.1-175m, the Doppler velocimeter may not reach the bottom and output an invalid bottom velocity due to the limited working range when the gravimeter is just submerged. The Doppler velocimeter bottom height output Alt is judged. If Alt = 0, the gravimeter is used as the primary navigation system, and the horizontal position of the ultra-short baseline underwater positioning system and the depth of the depth gauge are used as the observation quantities to construct the underwater strapdown dynamic gravity measurement system. If Alt ≠ 0, the gravimeter is used as the primary navigation system, and the velocity of the Doppler velocimeter, the horizontal position of the ultra-short baseline underwater positioning system and the depth of the depth gauge are used as the observation quantities to construct the underwater strapdown dynamic gravity measurement system.

[0049] By constructing a strapdown dynamic gravity measurement system on the surface or underwater in real time based on the current status of the gravimeter during navigation, gravity measurement on the surface and underwater can be achieved.

[0050] Step 106 , performing gravity measurement using a strapdown dynamic gravity measurement system to obtain high-precision speed, position, and attitude information; and performing calculations based on the high-precision speed, position, and attitude information to obtain an original gravity anomaly value.

[0051] Step 108: Filter the original gravity anomaly value using a low-pass filter to obtain an effective gravity anomaly result; use the gravimeter to collect static data of the celestial accelerometer after the voyage and filter it to obtain a final celestial relative force; construct a celestial accelerometer drift model for the current voyage based on the initial celestial relative force and the final celestial relative force.

[0052] After the measurement, the gravimeter returns to the dock to collect static data of the celestial accelerometer. After low-pass filtering, a final celestial relative force is obtained. Combined with the initial celestial relative force before the voyage, a celestial accelerometer drift model for this voyage is constructed. This model describes the change in the celestial accelerometer drift over time from the time it comes to rest before the voyage to the time it comes to rest after the voyage. This model can be used to calibrate gravity anomaly results and obtain more accurate gravity measurement results.

[0053] Step 110 , calibrate the effective gravity anomaly result using an initial celestial specific force, a celestial accelerometer drift model, and the gravity value of the onshore reference point of the gravimeter to obtain a final gravity measurement result.

[0054] Gravity measurement is a relative measurement. Having a benchmark point on shore can provide a benchmark value, making the measurement result more realistic. Secondly, the accelerometer data in the gravimeter will drift over time. After compensating for the drift model, the measurement result will be more accurate.

[0055] In the strapdown dynamic gravity measurement method for mixed surface and underwater operations, the gravity value of the shore reference point of the gravimeter is first obtained; static data of the celestial accelerometer before sailing is collected and noise filtered based on the gravimeter to obtain an initial celestial specific force; during the sailing process, the current state of the gravimeter is judged by the autonomous detection system, and a surface or underwater strapdown dynamic gravity measurement system is constructed based on the judgment result; gravity measurement is performed using the strapdown dynamic gravity measurement system to obtain high-precision speed, position and attitude information; based on the high-precision speed, position and attitude information, the celestial accelerometer is subjected to static data collection and noise filtering to obtain an initial celestial specific force. The attitude information is calculated to obtain the original gravity anomaly value; the original gravity anomaly value is filtered using a low-pass filter to obtain the effective gravity anomaly result; the static data of the celestial accelerometer after navigation is collected using the gravimeter and filtered to obtain a final celestial relative force; the celestial accelerometer drift model of the current voyage is constructed based on the initial celestial relative force and the final celestial relative force; the effective gravity anomaly result is calibrated using the initial celestial relative force, the celestial accelerometer drift model and the gravity value of the gravimeter's onshore reference point to obtain the final gravity measurement result. The present application performs gravity measurement by constructing a surface or underwater strapdown dynamic gravity measurement system in real time based on the current state of a gravimeter during navigation, and constructs a celestial accelerometer drift model using an initial celestial relative force before navigation and a final celestial relative force after navigation. The application also calibrates effective gravity anomaly results using the initial celestial relative force, the celestial accelerometer drift model, and the gravity value of the gravimeter's onshore reference point. This application not only enables dynamic gravity measurement on the surface and underwater, but also has simple operation, easy execution, and strong versatility, and improves the accuracy of gravity measurement.

[0056] In one embodiment, during navigation, the current state of a gravimeter is determined by an autonomous detection system, and a surface or underwater strapdown gravity measurement system is constructed based on the determination result, including:

[0057] During navigation, the threshold of the depth gauge is pre-set to 1.1. If the pressure value of the depth gauge P DG ≥1.1, and the number of satellites received by the satellite receiver N is less than 4, the gravimeter is judged to be underwater;

[0058] If the pressure value of the depth gauge is P DG <1.1, or the number of satellites received by the satellite receiver N ≥ 4, the gravimeter is judged to be on the water surface.

[0059] In one embodiment, when the gravimeter is detected on the water surface, a strapdown dynamic gravity measurement system of the water surface is constructed using the gravimeter as the main navigation system and GNSS as the observation quantity;

[0060] When the gravimeter is detected underwater, the Doppler velocimeter bottom height output Alt is judged. If Alt = 0, an underwater strapdown dynamic gravity measurement system is constructed with the gravimeter as the main navigation system, the horizontal position of the ultra-short baseline underwater positioning system, and the depth of the depth gauge as the observation quantities; if Alt ≠ 0, an underwater strapdown dynamic gravity measurement system is constructed with the gravimeter as the main navigation system, the speed of the Doppler velocimeter, the horizontal position of the ultra-short baseline underwater positioning system, and the depth of the depth gauge as the observation quantities.

[0061] In a specific embodiment, the gravimeter is affected by its own device characteristics, and the speed, position and attitude information of its navigation solution will diverge over time. The present application uses a depth meter, a Doppler velocimeter and an ultra-short baseline underwater positioning system to correct the speed, position and attitude information to obtain more accurate navigation results. In addition, the calculation of the celestial force requires a high-precision attitude, and the attitude information can only be provided by the gravimeter.

[0062] In one embodiment, the raw gravity anomaly value is obtained by calculating based on high-precision velocity, position, and attitude information, including:

[0063] When the gravimeter is on the water surface, the original gravity anomaly value is calculated based on the high-precision speed, position and attitude information.

[0064]

[0065] Among them, f U V is the force of the sky; E 、V N East speed and north speed respectively; R N 、R M are the radii of the meridian and the celestial circle respectively; L is the geographic latitude; h is the height / depth; γ is the normal gravity value related to the latitude; ω is the angular velocity of the Earth's rotation.

[0066] In one embodiment, when the gravimeter is underwater, the original gravity anomaly value is calculated based on the high-precision speed, position and attitude information.

[0067]

[0068] Among them, γ w Correction for underwater gravity gradient.

[0069] In one embodiment, constructing a celestial accelerometer drift model for the current voyage based on a segment of initial celestial specific force and a segment of final celestial specific force includes:

[0070] The celestial accelerometer drift model of the current voyage is constructed based on an initial celestial relative force and a final celestial relative force:

[0071] Δ=a0+a1(t-t0)+a2(t-t0) 2

[0072]

[0073] Where Δ is the gravimeter celestial accelerometer drift; a0, a1 and a2 are the parameters of the gravimeter celestial accelerometer long-term drift model; t is the time point of the survey line, f s0 、f s1 、f s2 …f sn All represent any initial celestial relative force in a segment of initial celestial relative forces, t s0 , t s1 , t s2 …t sn represents f s0 、f s1 、f s2 …f sn The corresponding test time, t0 represents the starting time, f0 represents the celestial force at the starting time t0, f e0 、f e1 、f e2 …f en Indicates any final azimuth ratio in a segment of final azimuth ratio, t e0 , t e1 , t e2 …t en represents f e0 、f e1 、f e2 …f en The corresponding test time.

[0074] In a specific embodiment, a model parameter solution equation is constructed using a section of initial celestial relative force and a section of final celestial relative force. The equation is solved by the least squares method to obtain the parameters a0, a1 and a2 of the long-term drift model of the celestial accelerometer of the gravimeter, and the celestial accelerometer drift model is constructed using the parameters a0, a1 and a2.

[0075] In one embodiment, the effective gravity anomaly result is calibrated using an initial celestial specific force, a celestial accelerometer drift model, and a gravity value of an onshore reference point of a gravimeter to obtain a final gravity measurement result, including:

[0076] The effective gravity anomaly result is calibrated using an initial celestial specific force and celestial accelerometer drift model, and the final gravity measurement result is: in, Indicates that the static celestial force measurement value is obtained by averaging the initial celestial force, g b Indicates the gravity value of the shore reference point of the gravimeter.

[0077] It should be understood that although Figure 1 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. In addition, Figure 1 At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0078] In one embodiment, Figure 2 As shown, a strapdown dynamic gravity measurement system for surface and underwater mixed operations is provided, comprising: an initial celestial specific force detection module 202, a gravimeter state detection module 204, a gravity measurement module 206, a celestial accelerometer drift model construction module 208, and a gravity anomaly result calibration module 210, wherein:

[0079] An initial celestial force detection module 202 is used to obtain the gravity value of the shore reference point of the gravimeter; static data collection and noise filtering are performed on the celestial accelerometer before sailing based on the gravimeter to obtain an initial celestial force;

[0080] The gravimeter status detection module 204 is used to determine the current status of the gravimeter through the autonomous detection system during navigation, and to construct a surface or underwater strapdown dynamic gravity measurement system based on the determination result;

[0081] Gravity measurement module 206, configured to perform gravity measurement using a strapdown dynamic gravity measurement system to obtain high-precision velocity, position, and attitude information; and to perform calculations based on the high-precision velocity, position, and attitude information to obtain a raw gravity anomaly value.

[0082] The celestial accelerometer drift model construction module 208 is used to filter the original gravity anomaly value using a low-pass filter to obtain an effective gravity anomaly result; use the gravimeter to collect static data of the celestial accelerometer after the voyage and filter it to obtain a section of final celestial specific force; and construct the celestial accelerometer drift model for the current voyage based on the section of initial celestial specific force and the section of final celestial specific force;

[0083] The gravity anomaly result calibration module 210 is used to calibrate the effective gravity anomaly result using an initial celestial specific force, a celestial accelerometer drift model, and the gravity value of the onshore reference point of the gravimeter to obtain a final gravity measurement result.

[0084] In one embodiment, the gravimeter status detection module 204 is further configured to determine the current status of the gravimeter during navigation through an autonomous detection system, and to construct a surface or underwater strapdown gravity measurement system based on the determination result, including:

[0085] During navigation, the threshold of the depth gauge is pre-set to 1.1. If the pressure value of the depth gauge P DG ≥1.1, and the number of satellites received by the satellite receiver N is less than 4, the gravimeter is judged to be underwater;

[0086] If the pressure value of the depth gauge is P DG <1.1, or the number of satellites received by the satellite receiver N ≥ 4, the gravimeter is judged to be on the water surface.

[0087] In one embodiment, when the gravimeter is detected on the water surface, a strapdown dynamic gravity measurement system of the water surface is constructed using the gravimeter as the main navigation system and GNSS as the observation quantity;

[0088] When the gravimeter is detected underwater, the Doppler velocimeter bottom height output Alt is judged. If Alt = 0, an underwater strapdown dynamic gravity measurement system is constructed with the gravimeter as the main navigation system, the horizontal position of the ultra-short baseline underwater positioning system, and the depth of the depth gauge as the observation quantities; if Alt ≠ 0, an underwater strapdown dynamic gravity measurement system is constructed with the gravimeter as the main navigation system, the speed of the Doppler velocimeter, the horizontal position of the ultra-short baseline underwater positioning system, and the depth of the depth gauge as the observation quantities.

[0089] In one embodiment, the gravity measurement module 206 is further configured to calculate, based on high-precision velocity, position, and attitude information, a raw gravity anomaly value, including:

[0090] When the gravimeter is on the water surface, the original gravity anomaly value is calculated based on the high-precision speed, position and attitude information.

[0091]

[0092] Among them, f U V is the force of the sky; E 、V N East speed and north speed respectively; R N 、R M are the radii of the meridian and the celestial circle respectively; L is the geographic latitude; h is the height / depth; γ is the normal gravity value related to the latitude; ω is the angular velocity of the Earth's rotation.

[0093] In one embodiment, when the gravimeter is underwater, the original gravity anomaly value is calculated based on the high-precision speed, position and attitude information.

[0094]

[0095] Among them, γ w Correction for underwater gravity gradient.

[0096] In one embodiment, the celestial accelerometer drift model construction module 208 is further configured to construct a celestial accelerometer drift model for the current voyage based on a period of initial celestial relative force and a period of final celestial relative force, including:

[0097] The celestial accelerometer drift model of the current voyage is constructed based on the initial celestial relative force and the final celestial relative force:

[0098] Δ=a0+a1(t-t0)+a2(t-t0) 2

[0099]

[0100] Where Δ is the gravimeter celestial accelerometer drift; a0, a1 and a2 are the parameters of the gravimeter celestial accelerometer long-term drift model; t is the time point of the survey line, f s0 、f s1 、f s2 …f sn All represent any initial celestial relative force in a segment of initial celestial relative forces, t s0 , t s1 , t s2 …t sn represents f s0 、f s1 、f s2 …f sn The corresponding test time, t0 represents the starting time, f0 represents the celestial force at the starting time t0, f e0 、f e1 、f e2 …f en Indicates any final azimuth ratio in a segment of final azimuth ratio, t e0 , t e1 , t e2 …t en represents f e0 、f e1 、f e2 …f en The corresponding test time.

[0101] In one embodiment, the gravity anomaly result calibration module 210 is further configured to calibrate the effective gravity anomaly result using an initial celestial specific force, a celestial accelerometer drift model, and the gravity value of the onshore reference point of the gravimeter to obtain a final gravity measurement result, including:

[0102] The effective gravity anomaly result is calibrated using an initial celestial specific force and celestial accelerometer drift model, and the final gravity measurement result is: in, Indicates that the static celestial force measurement value is obtained by averaging the initial celestial force, g b Indicates the gravity value of the shore reference point of the gravimeter.

[0103] The specific limitations of a strapdown dynamic gravity measurement device for mixed surface and underwater operations can be found in the limitations of a strapdown dynamic gravity measurement method for mixed surface and underwater operations described above and will not be repeated here. Each module in the aforementioned strapdown dynamic gravity measurement device for mixed surface and underwater operations can be implemented in whole or in part through software, hardware, or a combination thereof. Each of the aforementioned modules can be embedded in or independent of a processor in a computer device in hardware form, or can be stored in a memory in the computer device in software form, so that the processor can call and execute the operations corresponding to each of the aforementioned modules.

[0104] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above 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.

[0105] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A strapdown dynamic gravity measurement method for mixed surface and underwater operations, characterized in that: The method comprises: Obtain the gravity value of the shore reference point of the gravimeter; Static data collection and noise filtering are performed on the celestial accelerometer before sailing using the gravimeter to obtain an initial celestial specific force; During navigation, the current status of the gravimeter is determined by the autonomous detection system, and a strapdown dynamic gravity measurement system is constructed on the surface or underwater based on the determination results; Using the strapdown dynamic gravity measurement system to perform gravity measurement to obtain high-precision speed, position and attitude information; Calculating based on the high-precision speed, position, and attitude information to obtain an original gravity anomaly value; filtering the original gravity anomaly value using a low-pass filter to obtain a valid gravity anomaly result; Using a gravimeter to collect static data of a celestial accelerometer after the voyage and filtering the data to obtain a final celestial relative force; constructing a celestial accelerometer drift model for the current voyage based on the initial celestial relative force and the final celestial relative force; The effective gravity anomaly result is calibrated using the initial celestial specific force, the celestial accelerometer drift model, and the gravity value of the onshore reference point of the gravimeter to obtain a final gravity measurement result.

2. The method according to claim 1, characterized in that During navigation, the current status of the gravimeter is determined by the autonomous detection system. Based on the determination results, a surface or underwater strapdown gravity measurement system is constructed, including: During navigation, the threshold of the depth gauge is pre-set to 1.

1. If the pressure value of the depth gauge P 深度计 ≥1.1, and the number of satellites received by the satellite receiver N is less than 4, the gravimeter is judged to be underwater; If the pressure value of the depth gauge is P 深度计 <1.1, or the number of satellites received by the satellite receiver N ≥ 4, the gravimeter is judged to be on the water surface.

3. The method according to claim 2, characterized in that The method further comprises: When the gravimeter is detected on the water surface, a strapdown dynamic gravity measurement system for the water surface is constructed using the gravimeter as the main navigation system and GNSS as the observation quantity; When the gravimeter is detected underwater, the Doppler velocimeter bottom height output Alt is judged. If Alt = 0, an underwater strapdown dynamic gravity measurement system is constructed with the gravimeter as the main navigation system, the horizontal position of the ultra-short baseline underwater positioning system, and the depth of the depth gauge as the observation quantities; if Alt ≠ 0, an underwater strapdown dynamic gravity measurement system is constructed with the gravimeter as the main navigation system, the speed of the Doppler velocimeter, the horizontal position of the ultra-short baseline underwater positioning system, and the depth of the depth gauge as the observation quantities.

4. The method according to claim 3, characterized in that Calculation is performed based on the high-precision speed, position, and attitude information to obtain the original gravity anomaly value, including: When the gravimeter is on the water surface, the original gravity anomaly value is calculated based on the high-precision speed, position and attitude information. Among them, f U V is the force of the sky; E 、V N East speed and north speed respectively; R N 、R M are the radii of the meridian and the celestial circle respectively; L is the geographic latitude; h is the height / depth; γ is the normal gravity value related to the latitude; ω is the angular velocity of the Earth's rotation.

5. The method according to claim 4, characterized in that The method further comprises: When the gravimeter is underwater, the original gravity anomaly value is calculated based on the high-precision speed, position and attitude information. Among them, γ w Correction for underwater gravity gradient.

6. The method according to claim 5, characterized in that Constructing a celestial accelerometer drift model for the current voyage according to the initial celestial specific force and the final celestial specific force, including: The celestial accelerometer drift model of the current voyage is constructed based on the initial celestial relative force and the final celestial relative force: Δ=a0+a1(t-t0)+a2(t-t0) 2 Where Δ is the gravimeter celestial accelerometer drift; a0, a1 and a2 are the parameters of the gravimeter celestial accelerometer long-term drift model; t is the time point of the survey line, f s0 、f s1 、f s2 …f sn All represent any initial celestial relative force in a segment of initial celestial relative forces, t s0 , t s1 , t s2 …t sn represents f s0 、f s1 、f s2 …f sn The corresponding test time, t0 represents the starting time, f0 represents the celestial force at the starting time t0, f e0 、f e1 、f e2 …f en Indicates any final azimuth ratio in a segment of final azimuth ratio, t e0 , t e1 , t e2 …t en represents f e0 、f e1 、f e2 …f en The corresponding test time.

7. The method according to claim 6, characterized in that The effective gravity anomaly result is calibrated using the initial celestial specific force, the celestial accelerometer drift model, and the gravity value of the onshore reference point of the gravimeter to obtain a final gravity measurement result, including: The effective gravity anomaly result is calibrated using the initial celestial specific force and celestial accelerometer drift model to obtain the final gravity measurement result: in, Indicates that the static celestial force measurement value is obtained by averaging the initial celestial force, g b Indicates the gravity value of the shore reference point of the gravimeter.

8. A strapdown dynamic gravity measuring device for mixed surface and underwater operation, characterized in that: The device comprises: An initial celestial relative force detection module is used to obtain the gravity value of the shore reference point of the gravimeter; static data collection and noise filtering are performed on the celestial accelerometer before sailing based on the gravimeter to obtain an initial celestial relative force; The gravimeter status detection module is used to determine the current status of the gravimeter through an autonomous detection system during navigation, and to build a surface or underwater strapdown dynamic gravity measurement system based on the judgment results; A gravity measurement module is configured to perform gravity measurement using the strapdown dynamic gravity measurement system to obtain high-precision speed, position, and attitude information; and to perform calculations based on the high-precision speed, position, and attitude information to obtain an original gravity anomaly value. A celestial accelerometer drift model construction module is configured to filter the original gravity anomaly value using a low-pass filter to obtain an effective gravity anomaly result; collect static data of the celestial accelerometer after the voyage using a gravimeter and filter the data to obtain a final celestial relative force; and construct a celestial accelerometer drift model for the current voyage based on the initial celestial relative force and the final celestial relative force; The gravity anomaly result calibration module is used to calibrate the effective gravity anomaly result using the initial celestial specific force, the celestial accelerometer drift model and the gravity value of the onshore reference point of the gravimeter to obtain a final gravity measurement result.

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