Accurate positioning and setting method suitable for large-scale inland river lighthouse buoy

Abstract

The invention provides a precise positioning and marking method suitable for a large inland river lighthouse buoy, and relates to the technical field of inland river channel operation and maintenance. Aiming at the problems that a traditional buoy setting method is large in positioning error, low in working efficiency, high in safety risk, not suitable for large-scale lighthouse buoy operation and the like, on the basis of detailed analysis of the stress condition of a lighthouse buoy in an anchoring state, through long-term field practice inspection, the positioning accuracy of the lighthouse buoy is greatly improved. A convenient calculation method for the minimum safety marked chain length is provided, a convenient calculation method for the distance between an anchoring point and a marked point is provided, and a method for achieving relevant parameter measurement through modern measurement technical means such as satellite positioning navigation and shipborne sounding equipment is provided. The working process for realizing accurate positioning and marking of the buoy of the large inland river lighthouse is provided, and the method has the characteristics of high operability, high buoy positioning accuracy, high working efficiency, low safety risk and the like.

Description

Technical Field

[0001] The invention relates to the field of buoy installation for waterway engineering in the water transport industry, and in particular to the precise positioning and marking construction of large inland river lightship buoys. Background Art

[0002] Lightship buoys are navigational aids for ships in inland waterways that are anchored at designated locations to help ships navigate safely, economically and conveniently. They are widely used in waters with complex navigation conditions such as the Yangtze River Three Gorges hub. In order to meet the waterway scale requirements and ensure the safety of ship navigation, lightship buoys need to be continuously optimized and adjusted according to the flow conditions of flow, flow pattern and water level.

[0003] Traditional small buoys are often fixed with anchor stones. The operator fastens the anchor stone with one end of the steel cable, and winds the other end around the buoy pile and retracts it through the winch of the navigation boat. The navigation boat tows the buoy to the position where the anchor stone is thrown according to the operator's experience. The anchor stone slowly sinks under the action of the navigation boat winch. After touching the bottom, the navigation boat tows the buoy to the predetermined mark. However, under the influence of water flow, wind direction and other conditions, the error of the buoy's mark position is large, and the adjustment efficiency is low.

[0004] A large number of 15-meter large lightships are used on the main line of the Yangtze River to replace the original small and medium-sized buoys to provide better services for ships. After the large-scale transformation of the buoys, the current large lightship buoys equipped with anchor chains and iron anchors are very different from the previous small and medium-sized buoys using steel cables to anchor stones. The traditional positioning method has problems such as low positioning accuracy and poor stability, which is difficult to meet the needs of modern inland shipping. How to select the appropriate anchor chain length according to the water flow conditions of the mark, how to determine the anchoring position according to the mark and the length of the anchor chain, and how to accurately identify the anchoring point are technical issues that affect the precise positioning and marking of large lightship buoys.

[0005] The invention patent with publication number CN 103538700 B proposes a deep-water navigation mark cable stopper and its laying method; the method is to use the invented cable stopper to clamp or loosen the steel cable in the deep-water river section of the Three Gorges Reservoir area to achieve the purpose of laying anchor stones; this method can prevent the steel wire rope from bouncing or shaking, and the operator can operate remotely to improve the safety of the operation. Since the waterway in the reservoir area is relatively wide, the requirements for the precise positioning of the navigation mark are not high, and this method does not involve technical issues such as how to select the anchoring position according to the mark position and environmental factors. Summary of the invention

[0006] In order to solve the problems of large positioning error, low work efficiency, high safety risk and unsuitability for large lightship buoy operations in traditional buoy setting methods, the present invention conducts a detailed analysis of the stress conditions of lightship buoys in an anchored state, and through long-term field practice tests, proposes a convenient calculation method for the minimum safe chain length for setting a mark, a convenient calculation method for the distance between the anchoring point and the setting point, a method for measuring relevant parameters using modern measurement technologies such as satellite positioning navigation and ship-borne depth sounding equipment, and a workflow for achieving precise positioning and setting of large inland lightship buoys. The present invention has the characteristics of strong operability, high buoy positioning accuracy, high work efficiency and low safety risk.

[0007] In order to realize the above technical features, the object of the present invention is achieved as follows: a method for accurately positioning and setting a buoy for a large inland river light ship comprises the following steps: Step 1, determination of the length of the lightship buoy anchor chain: According to the hydrological and meteorological data and the requirements of the waterway maintenance regulations, obtain the wind speed and current velocity data near the mark setting point; determine the anchor and anchor chain model parameters based on the buoy data; use the ship-borne water depth measurement equipment to detect the water depth data of the mark setting area, and determine the length of the anchor chain of the lightship buoy according to the calculation method of the minimum safe length of the anchor chain of the large lightship buoy; Step 2: Determine the azimuth distance of the anchor point relative to the mark point: Calculate the horizontal distance between the anchor point and the mark point according to the calculation method of the horizontal distance between the anchor point and the mark point of the large light ship buoy; and determine the azimuth distance of the anchor point relative to the mark point according to the direction of the wind flow resultant force, and plot it on the ship-borne satellite positioning equipment; Step 3: Marking of the construction vessel's position when anchoring: According to the calculation method of the azimuth distance of the construction ship's satellite antenna from the navigation mark, the construction ship is towed to the light ship buoy, and the azimuth distance of the construction ship's satellite antenna relative to the navigation mark is calculated, and the position of the construction ship when anchored is plotted in the ship-borne satellite positioning equipment; Step 4, preparation for anchoring: Lay the anchor chain of the length determined in step 1 flat on the deck of the lightship buoy, fasten the tail end of the anchor chain, and hang the anchor rope on the bow of the buoy; Step 5, anchoring operation: The construction vessel tows the lightship buoy to the vicinity of the ship's location. When arriving at the ship's location, the ship's speed relative to the ground is controlled to be 0 m / s, and the bow of the ship is in the opposite direction of the wind and current force. At this time, the safety rope described in step 4 is released, and the anchor is allowed to drag the anchor chain laid flat on the deck to the bottom of the river with its own weight.

[0008] Preferably, the method for calculating the minimum safe length of the anchor chain for the large lightship buoy comprises the following steps: Step 1.1, determine the maximum flow velocity and wind speed data near the waterway according to historical data and waterway maintenance standards; and calculate the resultant force on the lightship buoy according to fluid mechanics; Step 1.2: Use the ship-borne water depth measurement equipment to measure the actual water depth of the marked waters; at the same time, measure the height from the water surface to the chain outlet; Step 1.3, calculate the length of the overhanging anchor chain S1 according to the anchor chain model in the navigation data: ; Where, S1 is the length of the hanging anchor chain; Y is the height from the chain outlet to the river bottom; R max is the maximum wind force acting on the lightship buoy; q c is the weight per unit length of anchor chain in water; Step 1.4, look up navigation data and channel data to determine the anchor and anchor chain model and grip coefficient. The total grip of the anchor chain length S2 and the anchor should be equal to the wind force acting on the lightship buoy, that is, P=F=R max ,but: ; Where, S2 is the length of the anchor chain at the bottom; P is the gripping force provided by the anchor and the anchor chain at the bottom; F is the horizontal component of the tension at the bottom of the anchor chain; , are the holding coefficients of the anchor and the anchor chain respectively; W a is the weight of the anchor in the water; Step 1.5, minimum safe length of anchor chain for large lightship buoy: S=S1+S2.

[0009] Where S is the minimum safe length of anchor chain for large lightship buoy.

[0010] Preferably, the precise formula for the minimum safe chain length for throwing out the anchor chain of the large lightship buoy is: ; Among them, when the water depth is below 40m, the maximum wind speed is less than level 6, and the flow velocity is less than 3.5m / s, the precise formula for the minimum safe chain length of a 15m lightship buoy equipped with a 150kg Hall anchor and a φ20.5 anchor chain is calculated using the empirical formula for safe chain length: S=2H+60; Where: H is the water depth at the last link of the anchor chain undercover.

[0011] Preferably, the method for calculating the horizontal distance between the anchoring point of the large lightship buoy and the mark point comprises the following steps: Step 2.1, determine the average flow velocity and wind speed data near the waterway according to historical data and waterway maintenance standards; and calculate the resultant force on the lightship buoy according to fluid mechanics; Step 2.2, calculate the horizontal distance X between the chain mouth and the last link of the undercover anchor chain, which conforms to the catenary equation formula, that is: ; Where: R avr is the average wind force acting on the lightship; Step 2.3, where the length of the anchor chain at the bottom is S2, if the gripping force P provided by the anchor chain at the bottom is c Sufficient to offset the average wind force R acting on the lightship avr , that is, P c ≥R avr , then the straight length of the undercover anchor chain should be: S2=R avr / (λ2q c ); If the holding force P provided by the undercover anchor chain c Holding force P with anchor a The sum of the two can offset the wind force on the light ship, that is, P a +P c ≥R avr , then the straight length of the undercover anchor chain should be: S2=S-S1; Step 2.4, the calculation formula for the horizontal distance D between the anchor point of the large lightship buoy and the beacon point is: D=X+S2.

[0012] Preferably, the precise formula for the horizontal distance between the anchor point of a large lightship buoy and the mark point is: ; Among them, when the average wind speed is 2m / s and the average flow velocity is 3.5m / s, the precise formula for the horizontal distance between the anchor point and the beacon point of a 15m lightship buoy equipped with a 150kg Hall anchor and a φ20.5 stud anchor chain can be calculated using the empirical formula for the horizontal distance between the anchor point and the beacon point: D = H / 2 + 38; Parameters: D is the horizontal distance between the anchor point and the mark point; R avr is the resultant force of wind and current on the ship, q c is the unit anchor chain weight in water, W a is the weight of the anchor in water, λ2 is the holding coefficient of the anchor and the anchor chain, H is the water depth at the last link of the anchor chain, and Y is the height from the chain outlet to the river bottom.

[0013] Preferably, the method for calculating the azimuth distance between the navigation mark and the satellite antenna of the construction ship for setting the mark comprises the following steps: Step 3.1, fasten the lightship buoy to one side of the construction vessel in a towed manner; Step 3.2, determine the distance a from the satellite antenna to the bow according to the construction ship's ship data; Step 3.3, measure the vertical distance d from the navigation mark to the axis of the construction ship; and measure the distance b from the foot of the vertical to the bow of the construction ship; Step 3.4, calculate the azimuth distance from the beacon to the satellite antenna based on the Pythagorean theorem and trigonometric functions.

[0014] Preferably, satellite navigation positioning means is used to realize the coordinate point positioning of the anchor point and the mark point and the distance measurement between the coordinate points.

[0015] Preferably, a ship-borne depth sounder is used to measure the waterway depth.

[0016] The present invention has the following beneficial effects: 1. The present invention makes a detailed analysis of the stress conditions of the light ship buoy in the anchored state, and proposes a scientific calculation method and an empirical calculation method that has been verified by practice for the minimum safe length of the chain for setting a large buoy.

[0017] 2. The present invention proposes a scientific calculation method for the distance between the anchor point and the mark point and an empirical calculation method that has been verified by practice.

[0018] 3. The present invention proposes a method for measuring and converting parameters such as position coordinates, horizontal distance, and water depth by using modern surveying technologies such as satellite positioning navigation and ship-borne depth sounding equipment.

[0019] 4. The present invention proposes a method flow for realizing accurate positioning and marking of large inland river lightship buoys.

[0020] 5. The present invention has been verified in the specific practice of channel maintenance in the Yangtze River Three Gorges hub section, and has the characteristics of high buoy positioning accuracy, strong operability, high work efficiency, and low safety risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0022] Figure 1 Lightship at anchor diagram.

[0023] Figure 2 Force analysis diagram of lightship mooring system.

[0024] Figure 3 A bird's-eye view of the position relationship between the lightship and the construction vessel.

[0025] Figure 4Flowchart of the method for precise positioning and setting of buoys for large inland river lightships.

[0026] In the figure: a represents the horizontal distance between the satellite antenna and the bow of the construction ship; b represents the horizontal distance between the navigation mark and the bow axis of the construction ship; c represents the horizontal distance between the satellite antenna and the navigation mark axis; d represents the vertical distance between the navigation mark and the center axis of the construction ship; D represents the distance between the mark point and the anchor point; R represents the resultant force of wind and current on the lightship; T' represents the tension on the top of the anchor chain; T0 represents the tension on the bottom of the anchor chain; F represents the component of T0 in the horizontal direction; P represents the grip provided by the anchor and the undercover anchor chain; G represents the gravity of the suspended anchor chain in water; S1 represents the length of the suspended part of the anchor chain; S2 represents the length of the undercover part of the anchor chain; X represents the horizontal distance between the chain outlet and the last link of the undercover anchor chain; Y represents the height from the chain outlet to the river bottom; H ​​represents the water depth at the last link of the undercover anchor chain. DETAILED DESCRIPTION

[0027] The embodiments of the present invention are further described below in conjunction with the accompanying drawings.

[0028] Embodiment 1: See also Figure 1-4 In order to solve the problem of large errors in traditional buoy positioning, the present invention proposes a precise positioning method for large inland river lightship buoys by using a ship-borne satellite positioning system and water depth detection equipment through mechanical analysis and mathematical calculation. The method adopts the following technical solutions: The lightship buoy system is in a relatively balanced anchored state in the channel. Figure 1 As shown, a coordinate system is established with the last link of the undercover anchor chain before it leaves the ground as the origin, the river bottom elevation line as the x-axis, and the water depth line here as the y-axis. The unit is meter.

[0029] As attached Figure 2 As shown, the stress analysis is as follows: The lightship buoy is mainly affected by its own gravity, the vertical component of the anchor chain tension T' and the buoyancy of water in the vertical direction; and is mainly affected by the resultant force R of wind and flow and the horizontal component of the anchor chain tension T' on the horizontal axis.

[0030] The suspended part of the anchor chain in the water is mainly subject to its own gravity G, buoyancy and the pulling force of the buoy and the undercover anchor chain on both ends of the anchor chain; the horizontal friction force of the water flow on the anchor chain can be ignored, so the suspended part of the anchor chain S1 can be approximately regarded as a catenary shape.

[0031] The anchor chain of the bottom part is mainly subject to its own weight and buoyancy in the vertical direction and the vertical component of the tension T0 of the overhanging part of the anchor chain; in the horizontal direction, it is mainly subject to the gripping force P of the anchor and the bottom anchor chain and the horizontal component F of the tension T0 of the overhanging part of the anchor chain. When the buoy position is stable, the gripping force P provided by the anchor and the bottom anchor chain should not be less than F.

[0032] Among them, in a precise positioning and marking method applicable to a large inland river light ship buoy provided by the present invention, a method for calculating the minimum safe length of the anchor chain for the large light ship buoy includes the following steps: Step 1.1, determine the maximum flow velocity and wind speed data near the waterway according to historical data and waterway maintenance standards; and calculate the resultant force on the lightship buoy according to fluid mechanics; Step 1.2: Use the ship-borne water depth measurement equipment to measure the actual water depth of the marked waters; at the same time, measure the height from the water surface to the chain outlet; Step 1.3, calculate the length of the overhanging anchor chain S1 according to the anchor chain model in the navigation data: ; Where, S1 is the length of the hanging anchor chain; Y is the height from the chain outlet to the river bottom; R max is the maximum wind force acting on the lightship buoy; q c is the weight per unit length of anchor chain in water; Step 1.4, look up navigation data and channel data to determine the anchor and anchor chain model and grip coefficient. The total grip of the anchor chain length S2 and the anchor should be equal to the wind force acting on the lightship buoy, that is, P=F=R max ,but: ; Where, S2 is the length of the anchor chain at the bottom; P is the gripping force provided by the anchor and the anchor chain at the bottom; F is the horizontal component of the tension at the bottom of the anchor chain; , are the holding coefficients of the anchor and the anchor chain respectively; W a is the weight of the anchor in the water; Step 1.5, minimum safe length of anchor chain for large lightship buoy: S=S1+S2.

[0033] Where S is the minimum safe length of anchor chain for large lightship buoy.

[0034] Then, the precise formula for the minimum safe length of anchor chain for large lightship buoy is: ; Among them, when the water depth is below 40m, the maximum wind speed is less than level 6, and the flow velocity is less than 3.5m / s, the precise formula for the minimum safe chain length of a 15m lightship buoy equipped with a 150kg Hall anchor and a φ20.5 anchor chain is calculated using the empirical formula for safe chain length: S=2H+60; Where: H is the water depth at the last link of the anchor chain undercover.

[0035] Embodiment 2: In a precise positioning and marking method applicable to a large inland river lightship buoy provided by the present invention, a method for calculating the horizontal distance between the anchoring point and the marking point of the large lightship buoy includes the following steps: Step 2.1, determine the average flow velocity and wind speed data near the waterway according to historical data and waterway maintenance standards; and calculate the resultant force on the lightship buoy according to fluid mechanics; Step 2.2, calculate the horizontal distance X between the chain mouth and the last link of the undercover anchor chain, which conforms to the catenary equation formula, that is: ; Where: R avr is the average wind force acting on the lightship; Step 2.3, where the length of the anchor chain at the bottom is S2, if the gripping force P provided by the anchor chain at the bottom is c Sufficient to offset the average wind force R acting on the lightship avr , that is, P c ≥R avr , then the straight length of the undercover anchor chain should be: S2=R avr / (λ2q c ); If the holding force P provided by the undercover anchor chain c Holding force P with anchor a The sum of the two can offset the wind force on the light ship, that is, P a +P c ≥R avr , then the straight length of the undercover anchor chain should be: S2=S-S1; Step 2.4, the calculation formula for the horizontal distance D between the anchor point of the large lightship buoy and the beacon point is: D=X+S2.

[0036] That is, the precise formula for the horizontal distance between the anchor point of a large lightship buoy and the beacon point is: ; Among them, when the average wind speed is 2m / s and the average flow velocity is 3.5m / s, the precise formula for the horizontal distance between the anchor point and the beacon point of a 15m lightship buoy equipped with a 150kg Hall anchor and a φ20.5 stud anchor chain can be calculated using the empirical formula for the horizontal distance between the anchor point and the beacon point: D = H / 2 + 38; Parameters: D is the horizontal distance between the anchor point and the mark point; R avr is the resultant force of wind and current on the ship, q c is the unit anchor chain weight in water, W ais the weight of the anchor in water, λ2 is the holding coefficient of the anchor and the anchor chain, H is the water depth at the last link of the anchor chain, and Y is the height from the chain outlet to the river bottom.

[0037] Embodiment 3: In a precise positioning and marking method applicable to a large inland river light ship buoy provided by the present invention, a method for calculating the azimuth distance between the navigation mark and the satellite antenna of a construction ship for marking operation comprises the following steps: Step 3.1, fasten the lightship buoy to one side of the construction vessel in a towed manner; Step 3.2, determine the distance a from the satellite antenna to the bow according to the construction ship's ship data; Step 3.3, measure the vertical distance d from the navigation mark to the axis of the construction ship; and measure the distance b from the foot of the vertical to the bow of the construction ship; Step 3.4, calculate the azimuth distance from the beacon to the satellite antenna based on the Pythagorean theorem and trigonometric functions.

[0038] Furthermore, the precise positioning and marking method of the large inland river lightship buoy of the present invention adopts satellite navigation positioning means to realize the positioning of coordinate points such as anchoring points and marking points and the distance measurement between coordinate points.

[0039] Furthermore, the precise positioning and marking method for a large inland river lightship buoy of the present invention uses a ship-borne depth sounder to measure the waterway depth.

[0040] Embodiment 4: A precise positioning method for buoys of large inland lightships, such as Figure 4 As shown, the following steps are included: Step 1, determination of the length of the lightship buoy anchor chain: According to the hydrological and meteorological data and the requirements of the waterway maintenance regulations, the wind speed and current velocity data near the mark setting point are obtained; the anchor and anchor chain model parameters are determined according to the buoy data; the water depth data of the mark setting area is detected by using the ship-borne water depth measurement equipment, and the minimum safe chain length calculation method for the anchor chain of a large lightship buoy is used, that is, the method in Example 1 is used to determine the length of the anchor chain of the lightship buoy; Step 2: Determine the azimuth distance of the anchor point relative to the mark point: According to the method for calculating the horizontal distance between the anchor point and the mark point of the large light ship buoy, that is, using the method in Example 1, calculate the horizontal distance between the anchor point and the mark point; and determine the azimuth distance of the anchor point relative to the mark point according to the direction of the wind flow resultant force, and plot it in the ship-borne satellite positioning equipment; Step 3: Marking of the construction vessel's position when anchoring: According to the method for calculating the azimuth distance of the satellite antenna of the construction ship for the navigation mark setting operation, that is, using the method in Example 3, the construction ship is fastened to the light ship buoy in a towed manner, and the azimuth distance of the satellite antenna of the construction ship relative to the navigation mark is calculated, and the position of the construction ship when anchoring is plotted in the ship-borne satellite positioning equipment; Step 4, preparation for anchoring: Lay the anchor chain of the length determined in step 1 flat on the deck of the lightship buoy, fasten the tail end of the anchor chain, and hang the anchor rope on the bow of the buoy; Step 5, anchoring operation: The construction vessel tows the lightship buoy against the current and slowly sails to the ship's location. When it reaches the ship's location, the ship's speed relative to the ground is controlled to 0 m / s or a slight speed, and the bow of the ship is in the opposite direction of the combined force of the wind and flow. At this time, the safety rope described in step 4 is released, and the anchor is allowed to drag the anchor chain laid flat on the deck into the river bottom with its own weight.

[0041] Embodiment 5: The present invention is further described below by taking the buoy deployment operation of the "Lijia River" in the lower reaches of the river of the Gezhouba Water Conservancy Project as an example: Step 1, determine the coordinates of the Lijiahe buoy and plot the coordinates of the buoy in the ship-borne satellite positioning equipment; Step 2: According to the hydrological and meteorological data and the requirements of the waterway maintenance regulations, the maximum wind speed of the mark is 6, the maximum flow rate is 3.5m / s, and the average wind speed near the mark is 2m / s and the flow rate is 3m / s; according to the buoy data, the Lijiahe buoy is a 15m lightship, equipped with a 150kg Hall anchor and a φ20.5 diameter anchor chain; the actual water depth of the buoy mark during the dry season is about 9m using the ship-borne water depth measurement equipment; Calculate the minimum chain length according to the minimum safety mark chain length calculation method: Calculated by precise formula, the safety setting chain length is ; Calculated by empirical formula, the safety setting chain length is: S=2H+60=78m; It was determined that the length of the chain for the lightship buoy anchoring was 3 sections, about 82.5m.

[0042] Step 3: Calculate the horizontal distance between the anchor point and the mark point according to the calculation method of the horizontal distance between the anchor point and the mark point of the large light ship buoy. c Sufficient to offset the average wind force R acting on the lightship avr , so the horizontal distance between the anchor point of Lijiahe buoy and the mark point is: Calculated by the precise formula, the distance from the anchor point to the mark point is: ; Calculated by the precise formula, the distance from the anchor point to the mark point is: D = H / 2 + 38 = 42.5m; The anchor point can be determined to be about 42m in the opposite direction of the wind flow force of the mark point, and the coordinates of the anchor point can be plotted in the ship-borne satellite positioning equipment; Step 4: The construction vessel is towed to the light ship buoy. According to the ship data, the distance between the bow of the construction vessel and the satellite antenna is 20m. The distance between the navigation mark and the axis of the bow is 10m, and the vertical distance between the navigation mark and the axis of the ship is 5m. According to the calculation method of the azimuth distance between the navigation mark and the satellite antenna of the construction vessel for setting the mark, the coordinates of the mark ship position are calculated to be 11.2m to the left and rear of the anchor point at 26°34'. The coordinates of the construction vessel position when anchoring are plotted in the ship-borne satellite positioning equipment; Step 5, laying the anchor chain of the length described in step 1 on the deck of the lightship buoy, fastening the tail end of the anchor chain, and hanging the anchor rope on the bow of the lightship buoy; Step 6: After the construction vessel sails slowly to the vicinity of the marking position against the combined force of wind and current, it maintains the bow direction and controls the speed of the vessel to approach 0m / s when it reaches the ship position. At this time, the lightship drops anchor, and the anchor sinks to the bottom of the river by free fall. The construction vessel releases the lightship buoy, completing the marking operation.

Claims

1. A method for accurately positioning and setting buoys for large inland river lightships, characterized in that: The following steps are involved: Step 1, determination of the length of the lightship buoy anchor chain: According to the hydrological and meteorological data and the requirements of the waterway maintenance regulations, obtain the wind speed and current velocity data near the mark setting point; determine the anchor and anchor chain model parameters based on the buoy data; use the ship-borne water depth measurement equipment to detect the water depth data of the mark setting area, and determine the length of the anchor chain of the lightship buoy according to the calculation method of the minimum safe length of the anchor chain of the large lightship buoy; Step 2: Determine the azimuth distance of the anchor point relative to the mark point: Calculate the horizontal distance between the anchor point and the mark point according to the calculation method of the horizontal distance between the anchor point and the mark point of the large light ship buoy; and determine the azimuth distance of the anchor point relative to the mark point according to the direction of the wind flow resultant force, and plot it on the ship-borne satellite positioning equipment; Step 3: Marking of the construction vessel's position when anchoring: According to the calculation method of the azimuth distance of the construction ship's satellite antenna from the navigation mark, the construction ship is towed to the light ship buoy, and the azimuth distance of the construction ship's satellite antenna relative to the navigation mark is calculated, and the position of the construction ship when anchored is plotted in the ship-borne satellite positioning equipment; Step 4, preparation for anchoring: Lay the anchor chain of the length determined in step 1 flat on the deck of the lightship buoy, fasten the tail end of the anchor chain, and hang the anchor rope on the bow of the buoy; Step 5, anchoring operation: The construction vessel tows the lightship buoy to the vicinity of the ship's location. When arriving at the ship's location, the ship's speed relative to the ground is controlled to be 0 m / s, and the bow of the ship is in the opposite direction of the wind and current force. At this time, the safety rope described in step 4 is released, and the anchor is allowed to drag the anchor chain laid flat on the deck to the bottom of the river with its own weight.

2. The method for accurately positioning and setting a buoy for a large inland river lightship according to claim 1, characterized in that: The method for calculating the minimum safe length of the anchor chain for the large lightship buoy comprises the following steps: Step 1.1, determine the maximum flow velocity and wind speed data near the waterway according to historical data and waterway maintenance standards; and calculate the resultant force on the lightship buoy according to fluid mechanics; Step 1.2: Use the ship-borne water depth measurement equipment to measure the actual water depth of the marked waters; at the same time, measure the height from the water surface to the chain outlet; Step 1.3, calculate the length of the overhanging anchor chain S1 according to the anchor chain model in the navigation data: ； Where, S1 is the length of the hanging anchor chain; Y is the height from the chain outlet to the river bottom; R max is the maximum wind force acting on the lightship buoy; q c is the weight per unit length of anchor chain in water; Step 1.4, look up navigation data and channel data to determine the anchor and anchor chain model and grip coefficient. The total grip of the anchor chain length S2 and the anchor should be equal to the wind flow force on the lightship buoy, that is, P=F=R max ,but: ； Where, S2 is the length of the anchor chain at the bottom; P is the gripping force provided by the anchor and the anchor chain at the bottom; F is the horizontal component of the tension at the bottom of the anchor chain; , are the holding coefficients of the anchor and the anchor chain respectively; W a is the weight of the anchor in the water; Step 1.5, minimum safe length of anchor chain for large lightship buoy: S=S1+S2. Where S is the minimum safe length of anchor chain for large lightship buoy.

3. The method for accurately positioning and setting a buoy for a large inland river lightship according to claim 2, characterized in that: The precise formula for the minimum safe length of anchor chain for large lightship buoy is: ； Among them, when the water depth is below 40m, the maximum wind speed is less than level 6, and the flow velocity is less than 3.5m / s, the precise formula for the minimum safe chain length of a 15m lightship buoy equipped with a 150kg Hall anchor and a φ20.5 anchor chain is calculated using the empirical formula for safe chain length: S=2H+60; Where: H is the water depth at the last link of the anchor chain undercover.

4. The method for accurately positioning and setting a buoy for a large inland river lightship according to claim 3, characterized in that: The method for calculating the horizontal distance between the anchoring point of the large lightship buoy and the mark point comprises the following steps: Step 2.1, determine the average flow velocity and wind speed data near the waterway according to historical data and waterway maintenance standards; and calculate the resultant force on the lightship buoy according to fluid mechanics; Step 2.2, calculate the horizontal distance X between the chain mouth and the last link of the undercover anchor chain, which conforms to the catenary equation formula, that is: ； Where: R avr is the average wind force acting on the lightship; Step 2.3, where the length of the anchor chain at the bottom is S2, if the gripping force P provided by the anchor chain at the bottom is c Sufficient to offset the average wind force R acting on the lightship avr , that is, P c ≥R avr , then the straight length of the undercover anchor chain should be: S2=R avr / (λ2q c ); If the holding force P provided by the undercover anchor chain c Holding force P with anchor a The sum of the two can offset the wind force on the light ship, that is, P a +P c ≥R avr , then the straight length of the undercover anchor chain should be: S2=S-S1; Step 2.4, the calculation formula for the horizontal distance D between the anchor point of the large lightship buoy and the beacon point is: D=X+S2.

5. The method for accurately positioning and setting a buoy for a large inland river lightship according to claim 4, characterized in that: The precise formula for the horizontal distance between the anchor point and the beacon point of a large lightship buoy is: ； Among them, when the average wind speed is 2m / s and the average flow velocity is 3.5m / s, the precise formula for the horizontal distance between the anchor point and the beacon point of a 15m lightship buoy equipped with a 150kg Hall anchor and a φ20.5 stud anchor chain can be calculated using the empirical formula for the horizontal distance between the anchor point and the beacon point: D = H / 2 + 38; Parameters: D is the horizontal distance between the anchor point and the mark point; R avr is the resultant force of wind and current on the ship, q c is the unit anchor chain weight in water, W a is the weight of the anchor in water, λ2 is the holding coefficient of the anchor and the anchor chain, H is the water depth at the last link of the anchor chain, and Y is the height from the chain outlet to the river bottom.

6. The method for accurately positioning and setting a buoy for a large inland river lightship according to claim 4, characterized in that: The method for calculating the azimuth distance between the navigation mark and the satellite antenna of the construction ship for setting the mark comprises the following steps: Step 3.1, fasten the lightship buoy to one side of the construction vessel in a towed manner; Step 3.2, determine the distance a from the satellite antenna to the bow according to the construction ship's ship data; Step 3.3, measure the vertical distance d from the navigation mark to the axis of the construction ship; and measure the distance b from the foot of the vertical to the bow of the construction ship; Step 3.4, calculate the azimuth distance from the beacon to the satellite antenna based on the Pythagorean theorem and trigonometric functions.

7. A method for accurately positioning and setting buoys for large inland river lightships according to claim 6, characterized in that: Satellite navigation positioning is used to locate the coordinate points of anchor points and landmarks and measure the distance between the coordinate points.

8. The method for accurately positioning and setting buoys for large inland river lightships according to claim 7, characterized in that: The waterway depth is measured using a ship-borne depth sounder.

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