River center gradient observation method

Abstract

The application relates to a river center gradient observation method, which comprises the following steps: S1, formulating a river center gradient observation method; S2, developing a new gradient observer; S3, establishing a mathematical model; S4, formulating a new leveling observation method; and S5, formulating river center gradient observation results. The application provides a precise and simple river center gradient observation method, which can be applied in surveying, designing and construction of multiple inland waterway projects, provides guarantee for river center gradient observation, and provides basic data for design and construction.

Description

Technical Field

[0001] This invention relates to the field of hydrological observation technology for waterway engineering, and more specifically, to a method for observing river center gradient. Background Technology

[0002] River center gradient observation is a crucial component of inland waterway surveying and reservoir hydrological monitoring. The observation results serve as essential foundational data for the planning, design, construction, and operation management of projects such as ports, waterways, bridges, water conservancy, and flood control. River center gradient observation is generally used in projects such as gradient observation in mountainous reservoir areas and inland river gradient observation. For example, the "Youjiang Waterway Improvement Project (Border Between Two Provinces – Baise)" includes bank gradient observation and river center gradient observation. This project involves a mountainous river located in the tail end of a reservoir, with major dams upstream and downstream. Real-time water level, gradient, and flow velocity are significantly affected by dam impoundment and release. Water level changes are unpredictable under special circumstances, while the river gradient is typically small. Therefore, river center gradient observation methods must be highly real-time and achieve millimeter-level accuracy in elevation measurement. Currently, domestic and international methods for river center gradient observation mainly employ theodolite leveling rods or GNSS measurements.

[0003] The theodolite leveling rod method involves using a theodolite or total station to measure the horizontal position of a drifting river using a gradient observation device, simultaneously measuring the water surface elevation. The gradient is then calculated based on the distance between the two points and the difference in water surface elevation. This method can achieve millimeter-level accuracy in elevation measurement, but horizontal positioning is generally only at the decimeter level. It also requires a large number of observers, demands high skill levels from the observers, is difficult to conduct, has poor time synchronization, and the accuracy of the observation data is not 100%. Furthermore, the conventional leveling rods used are generally planar structures, and their position relative to the observer during free drift is often inconvenient for field observation. The limited length of the leveling rod may also be incompatible with the natural conditions of the observation, thus seriously affecting the quality of the observation results. In addition, there are no readily available gradient observation devices, which must be fabricated on-site.

[0004] The GNSS measurement method uses a satellite positioning measurement system to measure the horizontal position and elevation of the drifting river, and then calculates the gradient based on the distance between the two points and the GNSS elevation difference. Although this method has strong real-time performance and good synchronization between horizontal and vertical measurements, and the horizontal measurement accuracy can reach the centimeter level, the elevation accuracy can only reach the centimeter level at best. It cannot meet the requirement of millimeter-level accuracy for river center gradient observation in areas with small gradients. In addition, there are no ready-made gradient observation devices, and they need to be made on-site. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a method for observing river center gradient, which has a simple working principle, high plane positioning accuracy, high elevation observation accuracy, observation accuracy of up to 100%, strong applicability, high working efficiency, and strong time synchronization.

[0006] The technical solution adopted by this invention to solve its technical problem is: to construct a method for observing river center gradient, including the following steps:

[0007] S1. Develop a new observation method: adopt a combined operation method of GNSS plane positioning and leveling to measure river surface elevation;

[0008] S2. Development of a gradient observation device: including a GNSS positioning system, a level tube, a balancer, a mounting frame, a counterweight, and a drifting carrier. The GNSS positioning system is fixedly connected to the top of the level tube, the level tube is fixedly connected to the balancer, the bottom of the level tube is flexibly connected to the counterweight, the balancer is fixedly connected to the mounting frame, and the mounting frame is fixedly connected to the drifting carrier.

[0009] S3. Establish mathematical models: including distance models between gradient observation points, elevation difference models, and river center gradient models;

[0010] S4. Develop leveling observation methods: This includes developing leveling observation methods and making leveling observation auxiliary devices;

[0011] S5. Formulate the observation results of the river center gradient: including the content and form of the observation results of the river center gradient.

[0012] According to the above scheme, in step S1: GNSS plane positioning is achieved by automatic observation and recording using a satellite positioning instrument; river surface elevation measurement is achieved by leveling elevation measurement; the joint operation method is to simultaneously complete leveling observation and GNSS plane positioning; and the synchronization of the joint operation method is based on the recorded time.

[0013] According to the above scheme, in step S3, the distance model involves: reading the time and geodetic coordinates (B, L) of the positioning measurement data from the satellite positioning system measurement recorder; converting the geodetic coordinates (B, L) into reference ellipsoidal grid coordinates (X0, Y0); and then converting the reference ellipsoidal grid coordinates (X0, Y0) into engineering coordinates (X... n ,Y n Then, the distance between the two points is calculated using the engineering coordinates of the two adjacent points; Elevation difference model: using time as the retrieval point, the leveling observation and photography data are paired, and then the elevation difference is calculated based on the corresponding leveling observation data; Gradient model: the corresponding gradient is calculated based on the elevation difference and distance between the two points.

[0014] According to the above scheme, the process and mathematical transformation model of the distance model are as follows:

[0015] (1) The mathematical model for converting the geodetic coordinates (B,L) measured by satellite positioning into reference ellipsoidal grid coordinates (X0,Y0) is as follows:

[0016]

[0017]

[0018] In equations (1) and (2):

[0019]

[0020] l = L - L0 (L0 is the central meridian)

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031] (4) Convert the reference ellipsoid grid coordinates (X0, Y0) to engineering coordinates (X... n ,Y n The mathematical model is obtained using a four-parameter transformation:

[0032]

[0033] In the formula: Δx and Δy are translation parameters, θ is rotation parameter, and m is scale transformation parameter; (5) Distance mathematical model

[0034] If the search is based on time and the location data is matched, then:

[0035] Distance between two points According to the above scheme, in step S3, the elevation difference model is as follows:

[0036] (1) Model of elevation difference between adjacent gradient observation points at the same observation station

[0037] Water surface elevation at gradient observation point i i =H0+h0-(h i +d0)

[0038] Water surface elevation H at gradient observation point i+1 i+1=H0+h0-(h i+1 +d0)

[0039] H0 is the elevation of the known leveling point.

[0040] h0 is the leveling rod reading of the leveling instrument at the known point.

[0041] h i Compare the level tube readings at observation point i with those of the level instrument.

[0042] d0 is the fixed distance from the zero point of the level gauge on the level tube of the gradient instrument to the water surface.

[0043] Then, the elevation difference model between adjacent gradient observation points at the same station is as follows:

[0044] △h i，i+1 =H i -H i+1

[0045] That is, △h i，i+1 =h i+1 -h i (5)

[0046] (2) Model of elevation difference between adjacent gradient observation points at different observation stations

[0047] When observing station G, the water surface elevation at the i-th point of the gradient observation is:

[0048] H i =H G,0 +h G,0 -(h i +d0)

[0049] When observing station G+1, the water surface elevation at the (i+1)th point of the gradient observation is:

[0050] H i+1 =H G+1,0 +h G+1,0 -(h i+1 +d0)

[0051] H G,0 Elevation of known points measured by station G

[0052] h G,0 For the leveling instrument readings at station G, use the leveling rod to read the leveling point.

[0053] h i Compare the level readings of the level instrument at station G with those at observation point i.

[0054] H G+1,0 Elevation of known points measured by station G+1

[0055] h G+1,0 For the leveling instrument readings at known points at station G+1, use the leveling rod.

[0056] h i+1 For the leveling instrument at station G+1, the reading d0 of the level tube at observation point i+1 represents the fixed distance from the zero point of the level gauge on the circular level tube of the gradient instrument to the water surface.

[0057] The elevation difference model between adjacent gradient observation points at different stations is as follows:

[0058] △h i，i+1 =H i -H i+1

[0059] That is, △h i，i+1 =H G,0 -H G+1,0 +h G,0 -h G+1,0 +h i+1 -h i (6)

[0060] According to the above scheme, in step S3, the river mid-slope model is as follows:

[0061] The gradient between adjacent gradient points, r = Δh i,i+1 / s (7)

[0062] According to the above scheme, in step S4, the new leveling observation method uses an auxiliary device to assist the digital camera and level instrument in working together to complete the leveling observation.

[0063] According to the above scheme, in step S5, the results are presented in the form of charts based on the submitted data of the river center gradient observation.

[0064] The river midpoint gradient observation method of the present invention has the following beneficial effects:

[0065] 1. This invention has a reasonable design, a correct mathematical model, and is easy to operate. In the observation of the center gradient of rivers with a small gradient, it meets the requirements of centimeter-level horizontal positioning accuracy, millimeter-level elevation measurement accuracy, 100% accuracy of observation data, high work efficiency, and strong applicability. The implementation of the observation method is suitable for both inland conventional rivers and special mountain rivers for the observation of the center gradient.

[0066] 2. This invention is a new method with simple working principle, high observation accuracy, and strong time synchronization, which solves the technical problems of the current theodolite leveling rod method in the water transport industry, such as the large number of personnel required, low plane positioning accuracy, poor synchronization, low observation accuracy, and low elevation observation accuracy of the GNSS method. Attached Figure Description

[0067] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0068] Figure 1 This is a schematic diagram of the elevation for observing the river center gradient in this invention;

[0069] Figure 2 This is a schematic diagram of the elevation of the river center gradient leveling instrument of this invention;

[0070] Figure 3 This is a schematic diagram of the elevation of the river center leveling observation in this invention;

[0071] Figure 4 This is a schematic diagram of the river center gradient observation curve of the present invention;

[0072] In the picture: 1. GNSS locator, 2. Circular level tube, 3. Balancing device, 4. Mounting frame, 5. Counterweight, 6. Drifting carrier, 7. Level, 8. Tripod, 9. Camera bracket, 10. Digital camera. Detailed Implementation

[0073] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0074] like Figure 1-4 As shown, the river center gradient observation method of the present invention includes the following steps: S1, developing a new observation method; S2, developing a gradient observation device; S3, establishing a mathematical model; S4, developing a leveling observation method; S5, developing river center gradient observation results.

[0075] S1. Formulation of Observation Methods

[0076] River center gradient observation method: A combined operation method of GNSS horizontal positioning and leveling measurement of river surface elevation is adopted. That is, GNSS positioning replaces the traditional theodolite leveling rod method for horizontal positioning, leveling elevation measurement replaces GNSS method for height measurement, and leveling reading photogrammetry replaces traditional manual observation and recording.

[0077] S2. Development of a gradient observation device

[0078] The river gradient meter includes a GNSS positioning system, a level tube, a balancer, a mounting frame, a counterweight, and a drifting carrier.

[0079] The plastic steel balancer, iron fixing frame, lead or iron counterweight, and bamboo (wood) drift carrier are made using local materials.

[0080] A leveling tube of a certain length is designed based on the elevation difference of the riverbank and the gradient of the river.

[0081] Development of new measuring equipment: The production of an adjustable-length circular leveling tube to replace the traditional 2-3 meter rectangular leveling rod of the theodolite leveling rod method.

[0082] The GNSS positioning system was purchased from the market; the leveling tube was a rigid PV tube purchased locally, with "E" markings and numbers for a standard leveling rod on its outer wall; the balancer was fabricated on-site using rigid plastic steel and stainless steel rods, consisting of a fixed frame, a large ring, and a small ring from the outside in. The fixed frame and the fixed bracket were bolted together. The large ring was connected to the center of the fixed frame at two points along the center line of the fixed frame, and to the small ring at two points along the perpendicular line of the fixed frame. Both the large and small rings could rotate freely within a certain range; the leveling tube was fixedly connected to the inner wall of the small ring, and the lower end of the leveling tube was flexibly connected to the counterweight. The verticality of the leveling tube was automatically adjusted by the counterweight and the balance ring; the fixed bracket was a trapezoidal outer frame welded from steel; the rafting carrier was made of bamboo poles or materials with a certain buoyancy.

[0083] S3, Mathematical Model

[0084] The mathematical model mainly includes models of the distance and elevation difference between the gradient observation points.

[0085] 1. Distance Model: Read the time and geodetic coordinates (B, L) of the positioning measurement data from the satellite positioning measurement recorder; convert the geodetic coordinates (B, L) to reference ellipsoidal grid coordinates (X0, Y0); then convert the reference ellipsoidal grid coordinates (X0, Y0) to engineering coordinates (X... n ,Y n Its main processes and mathematical transformation model are as follows:

[0086] (1) The mathematical model for converting the geodetic coordinates (B,L) measured by satellite positioning into reference ellipsoidal grid coordinates (X0,Y0) is as follows:

[0087]

[0088]

[0089] In equations (1) and (2):

[0090]

[0091] l = L - L0 (L0 is the central meridian)

[0092]

[0093]

[0094]

[0095]

[0096]

[0097]

[0098]

[0099]

[0100]

[0101]

[0102] (2) Convert the reference ellipsoid grid coordinates (X0, Y0) to engineering coordinates (X... n Y m ), using four-parameter conversion

[0103] The mathematical model obtained by substitution is as follows:

[0104]

[0105] In the formula: Δx and Δy are translation parameters, θ is rotation parameter, and m is scale transformation parameter.

[0106] (3) Distance mathematical model

[0107] Using time as the retrieval point, and pairing descent point observation and positioning data, then:

[0108] Distance between two points 2. Elevation Difference Model

[0109] Using time as the retrieval point, and pairing elevation data of descent points, then:

[0110] (1) Model of elevation difference between adjacent gradient observation points at the same observation station

[0111] Water surface elevation at gradient observation point i i =H0+h0-(h i +d0)

[0112] Water surface elevation H at gradient observation point i+1 i+1 =H0+h0-(h i+1 +d0)

[0113] H0 is the elevation of the known leveling point.

[0114] h0 is the leveling rod reading of the leveling instrument at the known point.

[0115] h i Compare the level tube readings at observation point i with those of the level instrument.

[0116] d0 is the fixed distance from the zero point of the level tube of the gradient gauge to the water surface. The elevation difference model between adjacent gradient observation points at the same station is as follows:

[0117] △h i，i+1 =H i -H i+1

[0118] That is, △h i，i+1 =h i+1 -h i (5)

[0119] (2) Model of elevation difference between adjacent gradient observation points at different observation stations

[0120] When observing station G, the water surface elevation at the i-th gradient observation point is:

[0121] H i =H G,0 +h G,0 -(h i +d0)

[0122] When observing station G+1, the water surface elevation at the (i+1)th gradient observation point is:

[0123] H i+1 =H G+1,0 +h G+1,0 -(h i+1 +d0)

[0124] H G,0 Elevation of known points measured by station G

[0125] h G,0 For the leveling instrument readings at station G, use the leveling rod to read the leveling point.

[0126] h i Compare the level readings of the level instrument at station G with those at observation point i.

[0127] H G+1,0 Elevation of known points measured by station G+1

[0128] h G+1,0 For the leveling instrument readings at known points at station G+1, use the leveling rod.

[0129] h i+1 Compare the level readings of the level instrument at station G+1 with those at observation point i+1.

[0130] d0 is the fixed distance from the zero point of the level gauge on the level tube of the gradient instrument to the water surface.

[0131] The elevation difference model between adjacent gradient observation points at different stations is as follows:

[0132] △h i，i+1 =H i -H i+1

[0133] That is, △h i，i+1=H G,0 -H G+1,0 +h G,0 -h G+1,0 +h i+1 -h i (6)

[0134] 3. River mid-slope model

[0135] The gradient between adjacent observation points, r = Δh i,i+1 / s (7)

[0136] S4. Develop new leveling observation methods;

[0137] The new leveling observation method includes the development of river leveling observation method and the fabrication of auxiliary devices.

[0138] The method for observing river level is as follows: a combined operation method of digital camera and level instrument is adopted, that is, the observation method of using digital camera to photograph the data and scale images in the eyepiece of level instrument for leveling measurement.

[0139] Fabrication of the leveling observation auxiliary device: Based on the shapes of the level instrument and digital camera, the camera bracket is made into a "gate" shape, which is fixedly connected to the level instrument and flexibly connected to the camera, ensuring that the digital camera lens is aligned with the eyepiece of the level instrument.

[0140] S5. Develop river center gradient observation results: Based on the submitted content, develop the results in the form of charts and graphs.

[0141] The implementation process of this invention is as follows:

[0142] 1. Construction of river gradient device components: Select appropriate materials locally to manufacture plastic steel circular level tubes, plastic steel balancers, iron fixing frames, lead or iron counterweights, and bamboo (wood) drifting carriers.

[0143] 2. Location of water surface elevation observation points along the shoreline;

[0144] 3. Set the recording time for GNSS and digital cameras (accurate to the second);

[0145] 4. Calibrate GNSS and digital camera time synchronization;

[0146] 5. Assemble the river center gradient observation device in the survey area;

[0147] 6. Determine the relationship between the zero point of the level tube of the river center gradient instrument and the water surface;

[0148] 7. Move the river center gradient observer to the observation starting point;

[0149] 8. Set up the level and digital camera;

[0150] 9. Free-floating river mid-river gradient device;

[0151] 10. Conduct GNSS positioning, digital camera observation and recording;

[0152] 11. Read GNSS positioning and digital camera observation records;

[0153] 12. Develop a program to calculate the distance and elevation difference between two adjacent points observed for gradient;

[0154] 13. Develop a program to calculate the gradient between two adjacent observation points;

[0155] 14. Develop a program to generate tables and graphs of the river center gradient observation results;

[0156] 15. Submit the results of the river center gradient observation.

[0157] The results of the river mid-gradient observations are presented below:

[0158]

[0159] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for observing river center gradient, characterized in that, Includes the following steps: S1. Develop a new observation method: adopt a combined operation method of GNSS plane positioning and leveling to measure river surface elevation; S2. Development of a gradient observation device: including a GNSS positioning system, a level tube, a balancer, a mounting frame, a counterweight, and a drifting carrier. The GNSS positioning system is fixedly connected to the top of the level tube, the level tube is fixedly connected to the balancer, the bottom of the level tube is flexibly connected to the counterweight, the balancer is fixedly connected to the mounting frame, and the mounting frame is fixedly connected to the drifting carrier. S3. Establish mathematical models: including distance models between gradient observation points, elevation difference models, and river center gradient models; In step S3, the distance model involves: reading the time and geodetic coordinates (B, L) of the positioning measurement data from the satellite positioning system measurement recorder; converting the geodetic coordinates (B, L) into reference ellipsoidal grid coordinates (X0, Y0); and then converting the reference ellipsoidal grid coordinates (X0, Y0) into engineering coordinates (X...). n ,Y n Then, the distance between the two points is calculated using the engineering coordinates of the two adjacent points; Elevation difference model: using time as the retrieval point, leveling observation and photography data are paired, and then the elevation difference is calculated based on the corresponding leveling observation data; Gradient model: the corresponding gradient is calculated based on the elevation difference and distance between the two points; S4. Develop leveling observation methods: This includes developing leveling observation methods and making leveling observation auxiliary devices; S5. Formulate the observation results of the river center gradient: including the content and form of the observation results of the river center gradient.

2. The river mid-gradient observation method according to claim 1, characterized in that, In step S1: GNSS plane positioning is achieved by automatic observation and recording using a satellite positioning instrument; river surface elevation measurement is achieved by leveling elevation measurement; and the combined operation method is to simultaneously complete leveling observation and GNSS plane positioning, with the synchronization of the combined operation method based on the recorded time.

3. The river mid-gradient observation method according to claim 1, characterized in that, The process and mathematical transformation model of the distance model are as follows: (1) The mathematical model for converting the geodetic coordinates (B,L) measured by satellite positioning into reference ellipsoidal grid coordinates (X0,Y0) is as follows: (1) (2) In formulas (1) and (2): (2) The coordinates of the reference ellipsoid grid Convert to engineering coordinates The mathematical model is obtained using a four-parameter transformation: （3） In the formula: , For translation parameters, For rotation parameters, These are the scaling transformation parameters; (3) Distance mathematical model If the search is based on time and the location data is matched, then: Distance between two points (4).

4. The river mid-gradient observation method according to claim 3, characterized in that, In step S3, the elevation difference model is: (1) Model of elevation difference between adjacent gradient observation points at the same observation station Water surface elevation at gradient observation point i i =H0+h0-(h i +d0) Water surface elevation H at gradient observation point i+1 i+1 =H0+h0-(h i+1 +d0) H0 is the elevation of the known leveling point. h0 is the leveling rod reading of the leveling instrument at the known point. h i Compare the level tube readings at observation point i with those of the level instrument. d0 is the fixed distance from the zero point of the level gauge on the level tube of the gradient instrument to the water surface. Then, the elevation difference model between adjacent gradient observation points at the same station is as follows: △h i，i+1 =H i -H i+1 That is, △h i，i+1 =h i+1 -h i (5) (2) Model of elevation difference between adjacent gradient observation points at different observation stations When observing station G, the water surface elevation at the i-th point of the gradient observation is: H i =H G,0 +h G,0 -(h i +d0) When observing station G+1, the water surface elevation at the (i+1)th point of the gradient observation is: H i+1 =H G+1,0 +h G+1,0 -(h i+1 +d0) H G,0 Elevation of known points measured by station G h G,0 For the leveling instrument readings at station G, use the leveling rod to read the leveling point. h i Compare the level readings of the level instrument at station G with those at observation point i. H G+1,0 Elevation of known points measured by station G+1 h G+1,0 For the leveling instrument readings at known points at station G+1, use the leveling rod. h i+1 Compare the level readings of the level instrument at station G+1 with those at observation point i+1. d0 is the fixed distance from the zero point of the level gauge on the level tube of the gradient instrument to the water surface. The elevation difference model between adjacent gradient observation points at different stations is as follows: △h i，i+1 =H i -H i+1 That is, △h i，i+1= H G,0 -H G+1,0 +h G,0 -h G+1,0 +h i+1 -h i (6).

5. The method for observing river mid-gradient according to claim 4, characterized in that, In step S3, the river mid-slope model is as follows: The gradient between adjacent gradient points is r = Δh i,i+1 / s (7).

6. The method for observing river mid-gradient according to claim 1, characterized in that, In step S4, the leveling observation method uses an auxiliary device to assist the digital camera and level instrument in working together to complete the leveling observation.

7. The method for observing river mid-gradient according to claim 1, characterized in that, In step S5, the results are presented in the form of charts based on the submitted data from the river center gradient observation.

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