CN110988994A

CN110988994A - Positioning system

Info

Publication number: CN110988994A
Application number: CN201911194209.5A
Authority: CN
Inventors: 李凯; 刘铁; 化希瑞; 孙红林; 刘铁华; 张邦; 林昀
Original assignee: China Railway Siyuan Survey and Design Group Co Ltd
Current assignee: China Railway Siyuan Survey and Design Group Co Ltd
Priority date: 2019-11-28
Filing date: 2019-11-28
Publication date: 2020-04-10

Abstract

The invention discloses a positioning system, wherein a main GPS device is arranged at the tail part of a geophysical prospecting ship; the first GPS device is arranged at a first position of a towing vessel, and the towing vessel is connected with the tail of the geophysical prospecting ship; the second GPS device is arranged at a second position of the towing cable; at least two detectors arranged on the towing cable at preset intervals, wherein each detector forms a fixed relative position relationship with the main GPS device, the first GPS device and the second GPS device; and the analyzer is used for determining the absolute coordinate values of the at least two detectors at the first time point through the main position information, the first position information and the second position information. Therefore, the shape and the position of the towing cable can be accurately determined, and the accurate coordinate value of the detector can be obtained.

Description

Positioning system

Technical Field

The invention relates to the field of water area engineering, in particular to a positioning system for seismic exploration.

Background

The geophysical exploration method, which utilizes the difference between the elasticity and density of the underground medium and estimates the nature and form of the underground rock stratum by observing and analyzing the propagation rule of the seismic waves generated by artificial earthquake in the underground, is called seismic exploration. Seismic exploration in water area engineering is widely applied to engineering geological exploration, regional geological exploration, research on sedimentary strata in sea areas and the like.

However, existing techniques for locating streamer-mounted receivers suffer from inaccurate positioning or inability to adapt to complex environments.

Disclosure of Invention

In view of the above, the main objective of the present invention is to provide a positioning system, by which the accuracy of positioning the geophone by the water area seismic survey observation system is improved.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

a positioning system, the system comprising: a primary GPS device, a first GPS device, a second GPS device, an analyzer, and at least two receivers for seismic surveying;

the main GPS device is arranged at the tail part of the geophysical prospecting ship and used for acquiring main position information at a first time point;

the first GPS device is arranged at a first position of a towing vessel, and the towing vessel is connected with the tail of the geophysical prospecting ship and is used for acquiring first position information at a first time point;

the second GPS device is arranged at a second position of the streamer and is used for acquiring second position information at a first time point;

the main position information, the first position information and the second position information are coordinate values obtained by referring to a world geodetic coordinate system;

the at least two detectors are arranged on the towing cable at preset intervals, wherein each detector forms a fixed relative position relationship with the main GPS device, the first GPS device and the second GPS device;

and the analyzer is used for determining the absolute coordinate values of the at least two detectors at the first time point through the main position information, the first position information and the second position information.

In the above scheme, the system further comprises a signal generating device;

and the signal generating device is arranged at the tail part of the geophysical prospecting ship and is used for transmitting a vibration signal to a target area at the bottom of the water area at a second time point.

In the above scheme, the detector is configured to receive a reflected signal reflected by the target area, and send the reflected signal to the analyzer.

In the above scheme, the analyzer is further configured to analyze a propagation rule of the vibration signal in the geology of the target region through the reflected signal received by the detector, and determine the nature and the form of the geology of the target region according to the propagation rule.

In the above scheme, the system further comprises a main buoy system, a first buoy system and a second buoy system;

the main buoy system is arranged at the tail of the geophysical prospecting ship and used for fixing the main GPS device at the tail of the geophysical prospecting ship;

the first buoy system is arranged at the first position of the streamer and used for fixing the first GPS device on the first position of the streamer;

the second buoy system is arranged at the second position of the streamer and used for fixing the second GPS device at the second position of the streamer.

In the above solution, the system further comprises a navigation device;

the navigation device is used for communicating with the main GPS device, acquiring the main position information at a first time point, and adjusting the advancing route of the geophysical prospecting ship based on the main position information.

In the above scheme, the system further comprises a water blocking tape;

the water blocking tape is connected to the second GPS device at the second position of the towing cable and used for providing resistance opposite to the traveling direction of the second GPS device.

In the above scheme, when the number of the streamers is at least two, the system further comprises: an expander;

the spreading device is connected to the tail of the geophysical prospecting ship and used for separating at least two towing cables, and the separation distance between the towing cables is fixed.

According to the positioning system provided by the embodiment of the invention, the GPS devices are respectively arranged at the tail part of the geophysical prospecting ship, the first position of a towing cable towed by the geophysical prospecting ship and the second position of the towing cable, the absolute coordinates of each GPS device at a certain time point are obtained, and the coordinate values of each detector are calculated based on the relative position relation of each detector arranged on the towing cable at fixed distance intervals. Thus, accurate detector coordinate values are obtained.

Drawings

Fig. 1 is a block diagram of a positioning system according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a positioning system in a single cable scenario according to an embodiment of the present invention;

fig. 3 is a communication system according to an embodiment of the present invention;

fig. 4 is a block diagram illustrating a main GPS device according to an embodiment of the present invention when the main GPS device is fixed to the tail of a geophysical prospecting ship;

fig. 5 is a block diagram of a first GPS device fixed at a first position of a streamer according to an embodiment of the present invention;

fig. 6 is a block diagram of a second GPS device fixed at a second position of a streamer according to an embodiment of the present invention;

fig. 7 is a block diagram of another positioning system according to an embodiment of the present invention;

fig. 8 is a schematic structural diagram of a positioning system under a multi-cable condition according to an embodiment of the present invention.

Detailed Description

The related art methods for determining the position of streamers in seismic exploration mainly include the following methods:

in seismic exploration of water area engineering, as an overwater streamer cannot be directly positioned by using GPS equipment, the GPS equipment is often arranged on a seismic exploration ship, the GPS equipment records the track of the ship, a seismic source and the streamer are generally defaulted to be approximately a straight line in the post-processing process, and the depth of the ship is positioned on the horizontal plane.

The description of the related art regarding positioning techniques in seismic exploration is as follows:

the invention discloses a positioning method of seismic signal receiving equipment (publication number: 102540257B) of geophysical exploration company of Chongqing drilling engineering Limited company of China Petroleum group, which is described in a small-area water area, performs fixed data acquisition and positioning through a fixed steel wire rope, has low efficiency and is not suitable for large-area exploration and positioning work.

Wuhan university 'a waterproof GPS positioner suitable for waters work' designs a waterproof GPS device in waters, is not suitable for waters seismic exploration streamer location.

The invention patent of American I/O company's invention GPS-based underwater towed cable positioning system (publication number: 1271422C) discloses a marine seismic exploration multi-cable GPS towed cable positioning device.

The method disclosed in the method for positioning the seismic signal receiving equipment is only suitable for narrow river water areas in inland rivers, and the position of the detector is determined by using the fixed steel wire rope, so that the construction efficiency is low, and the passage of a channel is influenced.

The device is suitable for wider marine environments, only one GPS device is arranged at the tail of each streamer and used for positioning the position of the streamer, and each detector determines the relative position through sound waves. For seismic exploration in offshore water areas and inland waterway water areas, wind surge, tidal tide and fall, the shapes of the towing cables are various, and higher requirements are placed on the positioning accuracy and depth of the towing cables of the geophones, so that a higher-accuracy positioning device and a higher-accuracy positioning method which are convenient and available are needed.

An embodiment of the present invention provides a positioning system, as shown in fig. 1, and fig. 1 is a schematic structural diagram of the positioning system provided in the embodiment of the present invention. Specifically, the method comprises the following steps:

a positioning system 10, the system comprising: a primary GPS device 11, a first GPS device 12, a second GPS device 13, at least two receivers 14 for seismic surveys, and an analyzer 15.

The positioning system provided by the embodiment of the invention is used for positioning the shape and the position of a streamer in seismic exploration and further determining the position of each geophone. The seismic exploration refers to a geophysical exploration method for deducing the nature and the form of an underground rock stratum by observing and analyzing the propagation rule of seismic waves generated by artificial earthquake in the underground by utilizing the difference of elasticity and density of an underground medium.

As shown in fig. 2, fig. 2 is a schematic structural diagram of a positioning system in a blanket situation according to an embodiment of the present invention.

In fig. 2, the main GPS device 11 is arranged at the tail of the geophysical prospecting ship; since the geophysical prospecting ship is in a non-stationary state, when the ship moves, the position at each time point is not fixed, and at this time, the main GPS device 11 acquires main position information at a first time point. Fig. 2 shows the buoy system 21 with the main GPS device 11 fixed, and only the main GPS device 11, the first GPS device 12 and the second GPS device 13 in fig. 2 can be seen in this case.

In fig. 2, the first GPS device 12 is arranged at a first position of the towing vessel 24, in the embodiment of the present invention, the first position is located at the middle of the towing vessel 24, the towing vessel 24 is connected to the tail of the geophysical prospecting ship, and the towing vessel 24 should ideally follow the track 22 when moving along with the movement of the geophysical prospecting ship, but due to the complex environment in the sea, the towing vessel 24 generally has a certain error from the track. The second GPS device 13 acquires first position information at a first time point.

In fig. 2, the second GPS device 13 is disposed at a second position of the streamers 24, which is located at the tail of the streamers 24 in the embodiment of the present invention, and is used for acquiring second position information at a first time point.

In this embodiment, the tail of the geophysical vessel can be roughly viewed as being at a vertical axis from the head of the streamers 24 towed behind the geophysical vessel. By arranging a plurality of GPS devices uniformly, the shape and the position of the towing cable 24 can be accurately and timely determined.

The main position information, the first position information and the second position information are coordinate values obtained by referring to a world geodetic coordinate system; the actual coordinate value is the coordinate value of the latitude and longitude of the earth where each GPS is located at the first time point measured by each GPS device.

As shown in fig. 2, the at least two receivers 14 are disposed on the streamer 24 at preset intervals, in general, 24 receivers or 48 receivers are disposed on one streamer, and the distance between the receivers 14 may be 2 meters, 3.125 meters, etc., which can be set by a person skilled in the art according to practical situations. Wherein each of the detectors 14 is in a fixed relative positional relationship with the primary GPS device 11, the first GPS device 12 and the second GPS device 13. It will be appreciated that the GPS devices are located at the head, middle and tail of the streamers 24, and the receivers 14 are evenly spaced at regular intervals on the streamers 24, so that the GPS devices and the receivers 14 have a fixed relative position.

The analyzer 15, on which the seismic acquisition system software is installed, as shown in fig. 3, communicates with the main GPS device 11, the first GPS device 12, and the second GPS device 13 on each buoy system through the RTK route 21, respectively, obtains position information obtained by each GPS at a first time point, and determines absolute coordinate values of the at least two detectors 14 at the first time point through an interpolation method according to the main position information, the first position information, and the second position information, where the interpolation method may be various interpolation methods such as lagrange or newton interpolation polynomial.

The main reasons why the specific position of each detector 14 can be calculated by interpolation are: many practical problems are represented by functions, and many functions can be understood only by experiments and observation. If a certain physical quantity in practice is observed, corresponding observed values are obtained at a plurality of different places, the interpolation method can find a polynomial, and a polynomial function which just passes through a plurality of known points on a two-dimensional plane can be given. By such a method, the specific coordinate values of the detectors 14 in the present invention can be calculated.

Specifically, the method comprises the following steps: the analyzer 15 calculates the coordinates after acquiring the coordinate values from the GPS devices with reference to the world geodetic coordinate system, that is, the seismic acquisition system software uses the coordinate data of the GPS to obtain the optimal target state information according to the least square principle, where the target state information is the state information that can most closely and truly reflect the current shape of the streamer 24, for example, the streamer 24 is 50 meters after being elongated, but the streamer 24 forms a curved shape in water due to wind waves or other reasons, and at this time, the analyzer 15 obtains the target state information that is most closely to the real state of the streamer 24 according to the least square principle, thereby ensuring the positioning accuracy and reliability.

At this time, the position information acquired by each GPS device is calculated by using a cubic spline interpolation method, and when the third derivative of the two end points is equal to the third derivative of the adjacent point of the two end points, the two ends of the streamer reach the non-kinking boundary, and at this time, the absolute coordinate value of each detector 14 can be obtained.

An embodiment of the present invention provides a positioning system, as shown in fig. 7, fig. 7 is a block diagram of another positioning system provided in the embodiment of the present invention. The positioning system 10 comprises, in addition to a main GPS device 11, a first GPS device 12, a second GPS device 13, at least two geophones 14 for seismic prospecting, and an analyzer 15, a signal generation device 16, a navigation device 17, a water blocking tape 18, and an expander 19.

And the signal generating device 16 is arranged at the tail part of the geophysical prospecting ship and is used for transmitting seismic wave vibration signals to a target area at the bottom of the water area at a second time point. The signal generating device 16 may be understood as an artificially generated seismic source, and the signal generating device 16 emits seismic wave vibration signals at regular time intervals, for example, every 1 second or 2 seconds, and the signals may be understood as seismic waves generated artificially in seismic exploration. In some embodiments, the signal generating device 16 is mounted in a boat shaped to resemble a submerged boat, the sides of which are fixedly attached to the aft portion of the geophysical vessel.

The detector 14 is adapted to receive a reflected signal, also a wave, reflected by the geology of the target area and to send the reflected signal to the analyzer 15.

The signal generating means 16 sends vibration signals at regular time intervals, each detector 14 will also receive the reflected signals of the vibration signals reflected from the seafloor geology of the target area, the detectors 14 send the received reflected signals to a geology acquisition system, the seismic acquisition system studies these data and infers the nature and morphology of the subsurface rock formations.

The analyzer 15 is further configured to analyze a propagation rule of the vibration signal in the geology of the target region through the reflected signal received by the detector, and determine the nature and the form of the geology of the target region according to the propagation rule. Of course, the analyzer 15 may also need to cooperate with the information provided by embodiments of the present invention for determining the exact location of each detector 14 in order to more accurately determine the nature and morphology of the geology of the current region.

The system 10 further includes a main buoy system 21, a first buoy system 22 and a second buoy system 23. The buoy system is capable of holding the buoy in a fixed position in a body of water or another body of water without the use of anchoring devices. The buoy in an embodiment of the invention includes a navigation control system for determining the position of the buoy relative to a desired station and a propulsion system for maneuvering and maintaining the buoy in the desired position or station. Wherein the propulsion system may consist of one or more propellers. When the geophysical prospecting ship advances according to a preset route, the rear towing cable cannot be completely ensured on the preset route due to complex environmental problems and physical reasons, and at the moment, a navigation control system of the buoy system can determine the deviation position of the buoy from the preset route.

The main buoy system 21 is arranged at the tail of the geophysical prospecting ship and used for fixing the main GPS device 11 at the tail of the geophysical prospecting ship; as shown in fig. 4, the main GPS device 11 is first fixed to the main buoy system 21, and then fixed to the tail of the geophysical prospecting ship through the buoy system 21.

The first buoy system 22 is arranged at the first position of the towing cable and is used for fixing the first GPS device 12 on the first position of the towing cable 24; as shown in fig. 5, the GPS device 12 cannot be directly fixed to the streamer, and therefore needs to be fixed to the streamer by a buoy system.

The second buoy system 23 is arranged at the second position of the streamer and is used for fixing the second GPS device 13 at the second position of the streamer 24. As shown in particular in fig. 6.

Each GPS device is provided with a fixed antenna which can be regarded as a transmitting station, the heights of the antennas are consistent, and all the antennas can leak out of the water surface under the action of the buoy system, so that the GPS devices and the RTK route 21 are guaranteed to realize information interaction. Each buoy system is provided with a hook, for example, if the buoy system is two meters long, a hook is respectively arranged at the position of one meter long and two meters long, and then the towing cables 24 are hung on the hooks, so that when the whole towing cable 24 is hung on the hook at the same height, the towing cable 24 can be ensured to sink at the position where the buoy system is arranged at the same distance from the water surface, and at the moment, accurate absolute height information of each detector 14 can be obtained through interpolation calculation.

The system 10 also comprises a navigation device 17; the navigation device 17 is configured to communicate with the main GPS device 11, acquire the main position information at a first time point, and adjust the traveling route of the geophysical prospecting ship based on the main position information.

The main GPS device 11 in fig. 2 is installed on the signal generating device 16 at the tail of the geophysical prospecting ship, and since both ends of the carrier on which the signal generating device 16 is installed are connected to the geophysical prospecting ship, it can be understood that the signal generating device 16 itself swings in the water, and thus it is important to measure the position of the signal generating device 16. Meanwhile, the main GPS device 11 communicates with the navigation device 17 to report the main position information to the navigation device 17, and the navigation device 17 adjusts the route of the geophysical prospecting ship by combining the main position information with a survey line preset by itself.

The system 10 further includes a water blocking tape 18; the water-blocking tape 18 is connected to the second GPS device 13 at the second position of the streamer 24, and is configured to provide resistance to the second GPS device 13 in a direction opposite to the traveling direction of the second GPS device, so that the second position of the streamer 24 is maintained within a preset distance range on the left and right sides of a preset route.

When the towing cable 24 moves forward along with the geophysical prospecting ship in water, due to wind, waves or other external reasons, the towing cable 24 can swing greatly in water, and in order to reduce the swing, the towing cable 24 can move forward along a preset route as much as possible, and therefore the measured shape and position of the towing cable 24 are relatively accurate.

By the mode that water flows into the large caliber of the water-blocking tape 18 and flows out from the small caliber, the resistance of the tail part of the towing cable 24 in the advancing direction of the geophysical prospecting ship is increased, which is equivalent to the increase of a backward pulling resistance at the tail part of the towing cable 24, so that the distance of the towing cable 24 deviating from the preset navigation route is maintained within a distance range, for example, the distance of the tail part of the towing cable 24 deviating from the preset navigation route is ensured within 5 meters.

In order to improve the stability of the towing cable 24, a towel with strong water absorption capacity can be added at the tail part of the towing cable 24 to increase the resistance at the tail part of the towing cable 24.

It should be noted that the embodiment of the present invention does not mention as large a drag as possible, and the drag is necessarily applied on the basis of ensuring that the geophysical prospecting ship can normally advance.

An embodiment of the present invention further provides a positioning system under a multi-cable condition, as shown in fig. 8, fig. 8 provides a schematic structural diagram of the positioning system under the multi-cable condition.

When the number of the streamers 24 is at least two, the system 10 further comprises: an expander 19;

the spreader 19 is connected to the tail of the geophysical prospecting ship and is used for separating at least two streamers 24, and the separation distance between the streamers 24 is fixed.

In fig. 8, specifically taking two towing streamers 24 as an example, when two towing streamers 24 are arranged at the tail of a geophysical prospecting ship, an expander 19 is arranged at the tail of the geophysical prospecting ship, the middle position of the expander 19 is connected with the tail of the geophysical prospecting ship, the expander 19 is supported between the two towing streamers 24 to fix the expander 19, and the expander 19 is supported at towing points 25 of the two towing streamers 24, so that the two towing streamers 24 are expanded to two sides of the tail of the geophysical prospecting ship, and the towing points 25 cannot be too close to the tail of the ship, so that the towing points 25 are prevented from being too greatly swung, and the calculated position information is not accurate.

When the main GPS device 11 measures the current main position information, the position information of the towing points 25 of each of the streamers 24 is calculated based on the fixed position difference with the respective towing points 25.

In fig. 8, when two streamers 24 are operated, the leading-in section of each streamer 24, that is, a section of each streamer 24 which is put down from a geophysical prospecting ship and enters a certain depth in water, the plane position immersed in water can be subjected to coordinate calculation by the main GPS device 11 to obtain the position information of the leading-in section of each streamer 24, and at this time, the seismic acquisition system on the analyzer 15 forms a three-dimensional seismic reflection comprehensive positioning network by communicating the signal generation device 16, the first GPS device 12 at the first position on each streamer 24 and the second GPS device 13 at the second position.

When the number of the streamers 24 is more than two, the distance separating the streamers 24 is a fixed value by the spreader 19. Thus, when the main GPS device 11 measures the current main position information, the position information of the towing points 25 of several towing cables 24 can be calculated by the fixed position difference.

After the position information of each tow point 25 at the first time point is determined by the master GPS device 11, the absolute coordinate value of each detector 14 on each tow cable 24 is calculated by cubic spline interpolation, similarly combining the first position information of the first time point provided by the first GPS device 12 and the second position information of the first time point provided by the second GPS device 13.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention.

Claims

1. A positioning system, characterized in that the system comprises: a primary GPS device, a first GPS device, a second GPS device, an analyzer, and at least two receivers for seismic surveying;

2. The positioning system of claim 1, further comprising a signal generating device;

3. The positioning system of claim 2,

and the detector is used for receiving the reflected signal reflected by the target area and sending the reflected signal to the analyzer.

4. The positioning system of claim 3,

the analyzer is further configured to analyze a propagation rule of the vibration signal in the geology of the target region through the reflected signal received by the detector, and determine the nature and the form of the geology of the target region according to the propagation rule.

5. The positioning system of claim 1, further comprising a main buoy system, a first buoy system and a second buoy system;

6. The positioning system of claim 1, further comprising a navigation device;

7. The positioning system of claim 1, further comprising a water blocking tape;

8. The positioning system of claim 1, wherein when there are at least two of said streamers, said system further comprises: an expander;