CN216013697U - Array type land time-varying gravity and gradient field observation device - Google Patents

Abstract

The utility model relates to an array type observation device for a land time-varying gravity and gradient field, which comprises an absolute gravimeter, a relative gravimeter, a positioning device, a data processing terminal, an observation pier array positioned outside a land measurement field and a reference point positioned inside the land measurement field.

Description

Array type land time-varying gravity and gradient field observation device

Technical Field

The utility model relates to the technical field of flow gravity observation, in particular to an array type observation device for land time-varying gravity and a gradient field.

Background

The gravity field is used as a basic geophysical field, and the static abnormal characteristics and the dynamic time change of the gravity field can provide important physical field information for researching the structure and the properties of the deep crust. In order to determine the gravity value and continuously monitor the change thereof, the current main method is to perform flow gravity observation. At present, the flow gravity simultaneous measurement of the seismic system has been carried out for more than 40 years, the large-scale absolute gravity measurement has also been carried out for nearly 15 years, and a flow gravity observation network consisting of 4000 relative gravity points and 100 absolute gravity points has been established nationwide. In the current stage, the land time-varying gravity observation mainly adopts a ground fixed-point repeated observation mode to realize the monitoring of the time-varying gravity field.

The existing seismic flow gravity observation network has two limitations: firstly, relative gravity observation is mainly used for measuring the net, absolute constraint points are few, measuring point intervals are uneven, the closing time of a measuring section is long, the whole net is measured for more months, the influence of uncertainty drift is large, and error transmission exists in adjustment results; secondly, due to the limitation of natural conditions and measurement modes, a plurality of measuring points are distributed around the highway, the environmental factors are complex, the observation time of a single measuring point is limited, the measuring items are single, and the gravity joint measurement is only used.

The relative gravity point observation device is an observation field which can be used for flow gravity joint measurement, and the main function of the gravity point is to measure on the observation device to obtain the relative gravity difference between points. The absolute gravity point observation device is an observation field which can be used for absolute gravity measurement. The absolute gravity measurement is carried out on the absolute gravity point, besides the absolute gravity value of the point is obtained, the vertical gravity gradient measurement is required to be carried out on each absolute gravity measurement, and the horizontal gravity gradient measurement is carried out only once on the newly-built absolute gravity point.

In order to measure the vertical gradient on an absolute gravity point, some observation teams use a tripod, and some observation benches which can be stacked high one on another are specially designed, but all auxiliary devices need to be installed, and an unstable observation base influences the data quality. Most of relative gravity points are located outdoors, the pier surface is basically level with the ground due to the limitation of site conditions, and even if auxiliary devices such as a tripod and the like are used for vertical gradient measurement, the quality of observation data caused by the influence of the environment such as airflow and the like cannot meet the precision requirement. The relative gravity point observation device for the flow gravity joint measurement is simple to construct and generally constructed outdoors; the absolute gravity point observation device can only be built indoors according to the row standard, and the construction is relatively complex.

SUMMERY OF THE UTILITY MODEL

In order to solve the problems in the prior art, the utility model designs an array type observation device for a land time-varying gravity and gradient field, a specific observation pier array and a specific reference point are arranged, and a gravity point value, a gravity horizontal gradient and a gravity vertical gradient of each measurement point can be obtained by combining an absolute gravimeter, a positioning device and a relative gravimeter, namely, the utility model can more efficiently obtain high-precision gravity field signals and more accurately identify field source gravity signals with specific space-time scales.

The utility model adopts the following technical scheme:

the utility model provides an array observation device of land time-varying gravity and gradient field, its characterized in that, include absolute gravimeter, relative gravimeter, positioner, data processing terminal, be located the outdoor observation mound array of land survey place and be located the indoor benchmark of land survey place, absolute gravimeter set up in the benchmark, it includes that a plurality of arranging according to field source sensitivity array are used for relative gravimeter to carry out the observation mound of relative gravity allies oneself with surveying, and each is surveyed the mound lower extreme and all is fixed in the underground, surveys the mound upper end and exposes in subaerial, exposes in subaerial observation mound the mound end and the mound face of mound and all is provided with the measuring point, absolute gravimeter, relative gravimeter and positioner all link to each other with data processing terminal.

Preferably, the gravity simultaneous measurement path of the observation point of each observation pillar is a measurement point from the reference point to the bottom of the first observation pillar, and the measuring point of the pier bottom, the pier surface and the pier bottom on the first observation pier returns once to the measuring point of the pier bottom of the second observation pier, the measuring point of the pier bottom, the pier surface and the pier bottom on the second observation pier returns once to the measuring point of the pier bottom of the next observation pier, repeating the steps until the measuring point of the pier bottom, the pier surface and the pier bottom on the last observation pier returns to the pier bottom of the first observation pier, and then returning to the measuring point of the pier bottom of the last observation pier, and then sequentially returning the measuring points of the pier bottoms of the observation piers from the measuring point of the pier bottom of the last observation pier until returning to the measuring point of the pier bottom of the first observation pier and then returning to the datum point.

Preferably, the gravity simultaneous survey path of the observation point of each observation pier is a measurement point from the reference point to the pier surface of the first observation pier, and the measuring point of the pier surface, the pier bottom and the pier surface on the first observation pier returns once to reach the measuring point of the pier surface of the second observation pier, the measuring point of the pier surface, the pier bottom and the pier surface on the second observation pier returns once to reach the measuring point of the pier surface of the next observation pier, repeating the steps until the measuring point of the pier surface, the pier bottom and the pier surface on the last observation pier returns to the pier surface of the first observation pier, and then returning to the measuring point of the pier surface of the last observation pier, and then sequentially returning the measuring points of the pier surfaces of the observation piers from the measuring point of the pier surface of the last observation pier until returning to the measuring point of the pier surface of the first observation pier and then returning to the datum point.

Preferably, the observation points of each observation pier further comprise a diagonal joint measurement path, and the diagonal joint measurement path is formed by sequentially carrying out diagonal joint measurement on each measurement point of each observation pier from a reference point and finally returning to the reference point.

Preferably, the observation piers arranged in an array are arranged at the same height on the ground, and the distance and the pier height of each observation pier in the array are adjustable according to site conditions, site source characteristics and different measured site source sensitivities; each observation pier is rectangular, T-shaped, L-shaped or step-shaped and is provided with at least one right angle arrangement.

Preferably, 4-9 observation piers are arranged in the observation pier array, and the distance between every two observation piers is 20-50 m.

Preferably, the absolute gravimeter comprises an FG5 absolute gravimeter and/or an A10 absolute gravimeter, the FG5 absolute gravimeter measures and selects not less than 12 combined grid data, and the A10 absolute gravimeter measures and selects not less than 24 combined grid data; the falling frequency of each combined grid data is not less than 100 times, and the qualified falling frequency is not less than 75 times.

Preferably, the observation pillars are 4 and rectangular, the gravity joint measurement path of the observation point of each observation pillar comprises 19 measurements in 9 positions of the reference point and the measurement point relative to the gravimeter, and the diagonal joint measurement path comprises 13 measurements in 9 positions of the reference point and the measurement point relative to the gravimeter.

The utility model has the technical effects that:

the utility model designs an array type observation device for a land time-varying gravity and gradient field, wherein an observation pier array is arranged outside a land measurement field, a reference point is arranged inside the land measurement field, an absolute gravimeter, a positioning device and a relative gravimeter are combined, after the gravity point value of the reference point is measured, the relative gravity joint measurement is carried out sequentially along the measurement points of each observation pier from the reference point after the gravity point value of the reference point is measured, the measurement of the gravity horizontal gradient and the vertical gradient is completed, and then a data processing terminal processes the measurement points to obtain the gravity point value, the gravity horizontal gradient and the gravity vertical gradient of each measurement point. For a single field, the change of the gravity vertical gradient caused by the shallow signal source has a higher signal-to-noise ratio compared with the conventional gravity measurement, the gravity horizontal gradient can be used for analyzing the sensitivity of the underground field source, the combined observation among the measurement points of a plurality of observation piers is designed, the sensitive area range of the observation network is adjusted by utilizing the sum and difference operation of the observation points during data processing, and the field source gravity signal with a specific space-time scale can be more favorably identified. If the system is in a key danger area, the gradient array gravity observation network constructed by the array type land time-varying gravity and gradient field observation device designed by the utility model can completely replace the traditional flowing gravity measurement network. Each field of the gradient array measuring network has absolute gravity observation, and the absolute gravity observation and the relative gravity observation are carried out simultaneously, so that a high-precision gravity field signal can be given. The gravity and gradient field measurement is completed in one field, the gravity joint measurement between points only needs an observer to handle the instrument in the field, the measurement of each point is quasi-static, the instrument lattice falling is avoided as far as possible, the joint measurement mode can effectively monitor the instrument drift, and therefore, the observation device ensures the high precision of the result. The gradient array observation network consisting of a plurality of gradient array observation fields does not need to increase any cost in the field implementation process, such as the joint measurement among 2 fields. Because each field has absolute gravity measurement, the networking is only on the data processing and research level, the field is not involved, and the workload of the field is not increased.

The utility model adopts a small-range array layout for measurement, is finished in one field, greatly reduces the measurement range, avoids the boat and vehicle overstrain of more than 400km per day of the traditional flowing gravity measurement network, reduces the field workload, is convenient for measurement execution and reduces the measurement cost. The measuring point is generally positioned in the seismic station, so that the environmental interference is small, and the high-speed social development cannot be damaged. The newly-built gravity gradient observation array has a construction standard far higher than a relative gravity measurement point and can be permanently used. The time spent for completing the survey in 1 field is less, the personnel work is more efficient, 2-3 people's observation teams can erect absolute gravimeters and GPS equipment for continuous measurement, when the instruments work, the observers carry out the joint survey of XYZ three-direction gravity gradient observation arrays, and the 1 field survey only takes about 2 days. Because the measuring area is small and only located in the station, the relative gravity measurement closing time is shortened. The gravity measurement performed on the XYZ three-direction gravity gradient observation array can be closed to an absolute gravity point at any time, the influence of instrument drift on an adjustment result is effectively reduced, the measured data misalignment caused by instrument grid dropping is avoided, and the data is more reliable.

Drawings

FIG. 1 is a schematic structural diagram of an array type land time-varying gravity and gradient field observation device according to the present invention.

FIG. 2 is a schematic diagram of one embodiment of an array of observation piers.

FIG. 3 is a schematic diagram of an embodiment of a relative gravity simultaneous measurement path.

Fig. 4 is a schematic diagram of a second embodiment of a relative gravity simultaneous measurement path.

FIG. 5 is a schematic diagram of an embodiment of a diagonal joint survey path.

Fig. 6 is a schematic view of an application scenario of the array type land time-varying gravity and gradient field observation device of the present invention.

FIG. 7 is a graph showing the results of horizontal gradients.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings.

The utility model relates to an array type observation device for a land time-varying gravity and gradient field, which comprises an absolute gravimeter, a relative gravimeter, a positioning device, a data processing terminal, an observation pier array positioned outside a land measurement field room and a reference point positioned in the land measurement field room, wherein the absolute gravimeter is arranged at the reference point, the observation pier array comprises a plurality of observation piers which are arranged in an array mode according to field source sensitivity and used for carrying out relative gravity joint measurement on the relative gravimeter, the lower end of each observation pier is fixed underground, the upper end of each observation pier is exposed on the ground, the pier surface and the pier bottom of the observation pier exposed on the ground are provided with measurement points, and the absolute gravimeter, the relative gravimeter and the positioning device are connected with the data processing terminal. That is to say, the absolute gravimeter is arranged on the reference point, and then the gravity point value of the reference point is measured to provide an absolute gravity reference of the land measurement field, wherein the reference point is the first measuring point of all relative gravity joint measurement; the positioning device is used for carrying out GNSS positioning on each observation pillar to obtain the longitude, the latitude, the elevation and the relative elevation of each measuring point; relative gravity joint measurement is sequentially carried out along each measuring point of each observation pier from a reference point by the relative gravimeter, the gravity joint measurement path at least returns to and fro once at each measuring point and returns to the reference point, and gravity readings of the relative gravimeter at the reference point and each measuring point are obtained to finish the measurement of the horizontal gradient and the vertical gradient of the gravity; and the data processing terminal acquires the gravity reading of the relative gravimeter and processes the data by combining the data obtained by the positioning device and the gravity point value of the reference point provided by the absolute gravimeter to obtain the gravity point value, the gravity horizontal gradient and the gravity vertical gradient of each measuring point.

FIG. 2 is a schematic diagram of one embodiment of an array of observation piers. The observation pier array is arranged outside a land measurement field 1 and comprises a plurality of observation piers 2, the lower ends of the observation piers 2 are fixed underground, the upper ends of the observation piers 2 are exposed on the ground, and measuring points are arranged on the pier bottoms and the pier faces of the observation piers 2 exposed on the ground. Preferably, the array consists of n (n is more than or equal to 3) observation piers with the same height (pier bottom surface to pier top surface) and bottom surfaces and top surfaces, at least 1 observation pier is arranged in a right angle mode, horizontal gravity gradients in XY two directions can be obtained through the right angle arrangement array, and vertical gravity gradients in Z direction can be obtained by each observation pier with the same height and bottom surfaces and top surfaces. The intra-array observation piers were designed according to DB/T19-2006, DB/T39-2010, DB/T5-2003. The distance and the pier height of each observation pier in the array are adjusted according to site conditions, site source characteristics and field source sensitivity of different measuring methods, each observation pier is rectangular, T-shaped, L-shaped or step-shaped, 4 observation piers 2 in the embodiment shown in figure 2 are arranged in a rectangular shape, the distance between the observation piers is 24m, and the pier height is 0.8 m. The distance between the observation piers in the array and the pier height can be adjusted according to field conditions, field source characteristics and field source sensitivity of different measurements. In actual operation, the observation pier array can be designed and established according to different measurement objects. Considering the environmental conditions of the measurement station, it is preferable to create an array of 4-9 observation piers, each at a pitch of 20-50m, at least 1 square arrangement.

In order to observe the land time-varying gravity and gradient field and obtain the gravity point value, the vertical gravity gradient and the horizontal gravity gradient of a measuring point, the utility model designs a set of efficient, time-saving and high-precision gravity joint measurement device, which mainly comprises the following working implementation steps: absolute gravity measurement, GNSS surveying positioning, relative gravity measurement, and data processing.

Absolute gravimeter measurement: if an absolute gravity observation point exists in a land area (such as a seismic station), the absolute gravity observation point can be directly utilized, and if not, a new point is constructed according to the seismic industry standard DB/T39-2010. According to the provisions of the earthquake industry standard DB/T39-2010, an observation room needs to be built and a datum point needs to be buried, wherein the datum point is an absolute gravity observation point and can be arranged on an absolute gravity observation pier (which can be called as a datum pier for distinguishing an observation pier arranged in an observation pier array outdoors aiming at relative gravity measurement later), and the specification of the pier surface is not less than 1000mm multiplied by 1000 mm; the pier surface is preferably 200mm higher than the ground, and the flatness of the pier surface is preferably 6 mm. The timeliness of measurement is considered, and the flat and stable ground of the existing observation pier or the bottom office of the station can be used as a temporary absolute gravity point.

The absolute gravity observation point not only provides an absolute gravity reference of the field, but also provides a first measurement point of all relative gravity joint measurement, and the relative gravity measurement is combined with the absolute gravity point to transmit a gravity value to each observation position; in the relative gravity measurement, it is preferable to measure the absolute gravity point 1 time every 4 hours and monitor the null shift of the instrument in real time. The instrument used for absolute gravimetry is preferably an absolute gravimeter of two models, FG5 and/or a10, the measurement steps of the two absolute gravimeters are the same, and the following conditions are preferably satisfied during the data acquisition process: 1) each measuring point FG5 absolute gravimeter is not less than 13 combination grid data, and A10 absolute gravimeter is not less than 24 combination grid data; 2) the falling frequency of each group is not less than 100 times, the qualified falling frequency is not less than 75 times, and the group is effective; 3) the observation starting time of each group is set at the hour of the integral point or 30 minutes, an FG5 absolute gravimeter observes 1 group per hour, and an A10 absolute gravimeter observes 2 groups per hour; 4) the instrument stops working for more than 10h, the previous observation is invalid, and the observation needs to be restarted. And after data acquisition is finished, obtaining an absolute gravity point value of the absolute gravity observation point.

Positioning device GNSS measures location: if a GPS reference station in an existing global satellite navigation system GNSS within a land area, such as a seismic station, is available directly. If not, new points are built according to the common monument of the national standard GBT 18314-2009. The timeliness of measurement is considered, an observation pier with good visual conditions in an observation array can be used, a centering disk is arranged on the pier surface, and the global positioning system equipment is connected.

The GPS adopts a reference station observation mode of continuous operation based on satellite positioning, continuous observation or differential positioning and the like to complete measuring point positioning according with precision. And the vertical change of the measuring point is accurately measured by matching leveling measurement between the points. The phase center stability should be better than 1mm in the horizontal direction and better than 2mm in the vertical direction.

When the field is measured for the first time, GPS positioning and leveling measurement are required to be carried out on each observation pier, the longitude, the latitude, the elevation and the relative elevation of each measurement position are given, the point positions are reduced to the same horizontal plane, and the gravity horizontal gradient can be calculated by combining the relative gravity measurement values and the horizontal distance between each measurement point; the height difference between the bottom surface and the top surface of the pier is observed as a determined value, and the vertical gradient of gravity can be calculated by combining a relative gravity measurement value. During repeated observation, the data of the first positioning is used for carrying out horizontal gradient reduction and vertical gradient reduction, but GPS positioning and leveling of each point position are still needed to be carried out in an observation pier, so that the relative elevation change among the measuring points is monitored.

And (3) measuring relative to a gravimeter: in order to improve the measurement efficiency and save the measurement time, the utility model designs a relative gravity measurement circuit. As an embodiment, taking 4 observation pillars arranged in a rectangular array as an example, the circuit design of relative gravity measurement is described, as shown in fig. 3, a vertical gravity gradient can be obtained by joint measurement of a top surface measurement point and a bottom surface measurement point of each observation pillar, a horizontal XY-direction gravity gradient and a gravity point value can be obtained by joint measurement between the bottom surface measurement points of each observation pillar, and an absolute gravity value can be introduced into a gradient observation array by measurement of the absolute gravity point, and a gravity value of each measurement point can be obtained. The gravity joint measurement path (i.e. measurement circuit) designed by the utility model relative to the gravity meter measurement is as shown in the figure, the measurement is carried out according to the observation sequence of numbers 1 and 2 … … 19, the measurement is carried out from the reference point 1 to the measurement point of the bottom of the first observation pier, and after the measurement point of the bottom of the first observation pier, the surface of the pier and the bottom of the pier, returns once to and fro (2-3-4), the measurement point 5 of the bottom of the second observation pier is moved to the measurement point 8 of the bottom of the next observation pier, and so on, after the measurement point of the bottom of the second observation pier, the surface of the pier and the bottom of the pier, returns to the measurement point 15 of the bottom of the last observation pier after the measurement point of the bottom of the last observation pier, the surface of the pier and the bottom of the pier, returns once to and fro (11-12-13), then, the measuring points (16-17-18) at the bottom of each observation pier are sequentially returned from the measuring point 15 at the bottom of the last observation pier until the measuring points are returned to the measuring point 18 at the bottom of the first observation pier and then returned to the reference point 19, and the embodiment only needs to carry out a total of 19 times of measurement at 9 positions, so that 9 measurement sections which are closed back and forth can be completed, and the gravity gradient in the horizontal and vertical directions and the gravity value of each measurement point can be obtained.

In the measuring process, the transmission of the absolute gravity point value of the first part to the gravity value of the gradient observation array of the part is finished by 1 and 2 (18 and 19 in the closing process) observation, meanwhile, the calibration of the absolute gravity value is realized, and the influence of null shift of a monitoring instrument is avoided. 2. And 1 complete closed joint measurement of the vertical gradient measurement is completed by 3 and 4 times of observation, the retransmission of the absolute gravity point value of the first part is completed by 4 and 5 times of observation (17 and 18 in the closed state), and the horizontal gradient measurement on the height of the bottom surface of the observation pier is also realized. 5. The joint measurement functions of 6 and 7 are the same as those of 2, 3 and 4, the functions of 7 and 8 are the same as those of 4 and 5, and the like. By adopting the joint measurement path, the XY-direction horizontal gradient measurement of 4 point positions is completed at the cost of only 5 measurements; the transfer of the gravity point value is completed at the cost of only 2 measurements while the calibration of the absolute gravity value is also achieved, when the whole measurement starts from the absolute measurement point position and ends up to this point. The measurement of the vertical gradient, the XY horizontal gradient and the relative gravity of the observation array is completed by 19 times of measurement, the operator only needs to walk around the field for 2 circles in the whole measurement process, and if the vertical gravity measurement, the horizontal gradient and the relative gravity measurement are respectively carried out, the measurement needs to be carried out for 23 times, and the operator needs to walk around the field for at least 3 circles.

In performing the measurements, the gravity gradient field is typically measured with reference to the observation pier bottom surface. In order to improve the observation accuracy, the measurement can be performed once again from the joint measurement of the absolute gravity point to the top surface of the pier, as shown in fig. 4, and the measurement is performed in the observation sequence of numbers 1 and 2 … … 19. The gravity simultaneous measurement path measured by the relative gravimeter is from a reference point 1 to a measurement point 2 of the pier surface of a first observation pier, and after the measurement point of the pier surface, the pier bottom and the pier surface on the first observation pier reciprocates for one time (2-3-4), the measurement point goes to a measurement point 5 of the pier surface of a second observation pier, and after the measurement point of the pier surface, the pier bottom and the pier surface on the second observation pier reciprocates for one time (5-6-7), the measurement point goes to a measurement point 8 of the pier surface of the next observation pier, and so on until the measurement point of the pier surface, the pier bottom and the pier surface on the last observation pier reciprocates for one time (11-12-13), the measurement point goes to a pier surface 14 of the first observation pier, the measurement point 15 of the pier surface of the last observation pier returns, and then the measurement points (16-17-18) of the pier surfaces of the observation piers return from the measurement point of the pier surface of the last observation pier in turn, until the measurement point 18, which returns to the pier face of the first observation pier, and then returns to the reference point 19.

Furthermore, the relative gravimeter carries out main measurement by using the gravity joint measurement path shown in fig. 3 and/or fig. 4, and auxiliary measurement is carried out after the main measurement, the auxiliary measurement is to sequentially and diagonally joint the relative gravimeter from the reference point along each measurement point of each observation pier to obtain the gravity readings of the relative gravimeter at the reference point and each measurement point, and the main measurement and the auxiliary measurement are combined to jointly complete the gravity horizontal gradient and vertical gradient measurement. That is, joint measurements may also be made for diagonal mounds in the gradient observation array, as shown in fig. 5, with measurements performed in the observation order of numbers 1, 2 … … 14.

A data processing terminal: and acquiring a gravity reading of the relative gravimeter, and calculating and processing the gravity reading by combining the data obtained by the positioning device and the gravity point value of the reference point provided by the absolute gravimeter to obtain the gravity point value, the gravity horizontal gradient and the gravity vertical gradient of each measuring point.

Taking the most common CG-5 relative gravimeter as an example, the current common measurement mode of the vertical gradient is to use 2 instruments, and take 'down-up-down' (or 'up-down-up') as one closure, 5 groups of closures (namely 11 measurements) are measured, each measurement is read by 5, and the working time of the instrument is at least 110 min; the utility model adopts an improved measuring mode, reduces the number of times of 'down-up-down' (or 'up-down-up') closure to 2 groups (namely 5 measurements), increases each measurement reading to 10, and has the working time of at least 100 min; the measurement time is shortened, and although the closing times are reduced, the observation time of each measurement is increased by 1 time, so that the data are more stable. Through experimental comparison, a stable absolute gravity observation pier in a Baijia village cave adopts a common measurement mode, the environmental precision is +/-1.02 uGal, and the standard deviation of the obtained gravity vertical gradient is +/-1.00-2.46 under the condition of consuming 132 min; and the improved measurement mode is completed by observing the pier in the field, the environment precision is +/-1.91 uGal, and the standard deviation of the obtained gravity vertical gradient is +/-1.04-1.18 under the condition of consuming 110 min. The improved measurement mode obtains a equivalent standard deviation of the gravity vertical gradient under the condition of less time consumption in the measurement environment with poorer environment precision (namely, higher noise).

Fig. 6 is a schematic view of an application scenario of the array type land time-varying gravity and gradient field observation device according to an embodiment of the present invention, specifically, a land time-varying gravity and gradient field observation array built in the field of the earth observation station in beijing. This embodiment consists essentially of a #01- #09 observation pier, a relative gravimeter, a GPS reference station, and a #10 reference point and corresponding absolute gravimeter arranged in a 3 x 3 array. The applicant uses the embodiment shown in fig. 6 to perform land time-varying gravity and gradient field observation in 2017, month 5 and 2017, month 10, respectively, wherein the joint measurement modes of fig. 3, fig. 4 and fig. 5 are sequentially used for relative gravity observation to ensure high accuracy of the result. The observation means comprises absolute gravity measurement, relative gravity measurement, GNSS measurement, leveling measurement and necessary auxiliary measurement work, and the obtained physical quantities are the gravity value, the horizontal gravity gradient and the vertical gravity gradient of each point position. In fig. 7, the horizontal gravity gradient calculated after the gravity values of all the observation piers are reduced to the height of observation pier #09 is shown, the arrow direction in the figure represents the difference direction of the horizontal section difference, the horizontal gradient unit in fig. 7 is uGal/m, and the horizontal gradient changes little in the directions #01- #02- #03 and has no obvious regularity; in the directions #01- #08- #07, the horizontal gradients are all positive values, the gravity value is increased all the time, and in the directions, a certain gravity horizontal gradient trend exists. In order to further ascertain the horizontal gradient characteristics in the field and study the change characteristics of the field gravity field, a gravity section is designed by taking the direction of a large arrow shown in fig. 7 as the direction of a laid encryption section, namely, in the field of the earth observation platform in the Beijing country, a low-speed layer, namely a karst cave, exists at the underground 80m of a C-A section (south-north direction). According to the measurement result, the device can be used for more efficiently obtaining high-precision gravity values and gravity field signals and more accurately inverting and identifying the field source gravity signals of a specific space-time scale.

It should be noted that the above-mentioned embodiments enable a person skilled in the art to more fully understand the utility model, without restricting it in any way. Therefore, although the present invention has been described in detail with reference to the drawings and examples, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the utility model.

Claims (8)

1. The utility model provides an array observation device of land time-varying gravity and gradient field, its characterized in that, include absolute gravimeter, relative gravimeter, positioner, data processing terminal, be located the outdoor observation mound array of land survey place and be located the indoor benchmark of land survey place, absolute gravimeter set up in the benchmark, it includes that a plurality of arranging according to field source sensitivity array are used for relative gravimeter to carry out the observation mound of relative gravity allies oneself with surveying, and each is surveyed the mound lower extreme and all is fixed in the underground, surveys the mound upper end and exposes in subaerial, exposes in subaerial observation mound the mound end and the mound face of mound and all is provided with the measuring point, absolute gravimeter, relative gravimeter and positioner all link to each other with data processing terminal.

2. The observation apparatus of claim 1 wherein the gravity-coupled path of the observation point of each observation pier is a measurement point from the reference point to the bottom of the first observation pier, and the measuring point of the pier bottom, the pier surface and the pier bottom on the first observation pier returns once to the measuring point of the pier bottom of the second observation pier, the measuring point of the pier bottom, the pier surface and the pier bottom on the second observation pier returns once to the measuring point of the pier bottom of the next observation pier, repeating the steps until the measuring point of the pier bottom, the pier surface and the pier bottom on the last observation pier returns to the pier bottom of the first observation pier, and then returning to the measuring point of the pier bottom of the last observation pier, and then sequentially returning the measuring points of the pier bottoms of the observation piers from the measuring point of the pier bottom of the last observation pier until returning to the measuring point of the pier bottom of the first observation pier and then returning to the datum point.

3. The observation apparatus of claim 1 wherein the gravity simultaneous survey path for the observation point of each observation pier is a measurement point from a reference point to the pier face of the first observation pier, and the measuring point of the pier surface, the pier bottom and the pier surface on the first observation pier returns once to reach the measuring point of the pier surface of the second observation pier, the measuring point of the pier surface, the pier bottom and the pier surface on the second observation pier returns once to reach the measuring point of the pier surface of the next observation pier, repeating the steps until the measuring point of the pier surface, the pier bottom and the pier surface on the last observation pier returns to the pier surface of the first observation pier, and then returning to the measuring point of the pier surface of the last observation pier, and then sequentially returning the measuring points of the pier surfaces of the observation piers from the measuring point of the pier surface of the last observation pier until returning to the measuring point of the pier surface of the first observation pier and then returning to the datum point.

4. The observation apparatus of claim 2 or 3 wherein the observation points of each observation pier further comprise a diagonal joint path, the diagonal joint path being measured sequentially diagonally from a reference point along each measurement point of each observation pier relative to the gravimeter and finally returning to the reference point.

5. The observation device of claim 4, wherein the observation piers arranged in an array are arranged at the same height on the ground, and the distance between the observation piers and the pier height in the array are adjustable according to site conditions, site source characteristics and different measured site source sensitivities; each observation pier is rectangular, T-shaped, L-shaped or step-shaped and is provided with at least one right angle arrangement.

6. The observation apparatus of claim 5 wherein the array of observation piers has 4 to 9 observation piers, and the distance between each observation pier is 20 to 50 m.

7. The viewing device of claim 1, wherein the absolute gravimeter comprises an FG5 absolute gravimeter and/or an a10 absolute gravimeter, the FG5 absolute gravimeter measuring and selecting no less than 12 combination grid data, an a10 absolute gravimeter measuring and selecting no less than 24 combination grid data; the falling frequency of each combined grid data is not less than 100 times, and the qualified falling frequency is not less than 75 times.

8. The observation device of claim 6 wherein the observation piers are 4 and rectangular, the observation point of each observation pier has a combined gravity path comprising 19 measurements relative to the gravimeter at 9 positions of the reference point and the measurement point, and the diagonal path comprises 13 measurements relative to the gravimeter at 9 positions of the reference point and the measurement point.

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