River-crossing leveling method and system

Abstract

The invention belongs to the technical field of engineering surveying, and particularly discloses a river-crossing leveling method and system.The method comprises the steps that four control points are arranged on the two sides of a water area to be measured, each control point is provided with a centering rod tool, and each centering rod tool is integrated with an upper-layer prism and a lower-layer prism with the preset fixed vertical distance; a first total station and a second total station are erected on the two banks of the water area, upper-layer prisms and lower-layer prisms arranged on centering rod tools on the opposite banks are observed synchronously and oppositely, and vertical angle and slant distance data of all observation targets are obtained; and based on the vertical angle and slope distance data, a preset fixed vertical distance is used as a checking condition, and the height difference between the target positions on the two banks is solved. According to the method, the double-layer prism tool is introduced into a physical forced closing check condition, and traditional quadrilateral geometric closing check is combined, so that the data redundancy and the reliability of results are greatly enhanced, and system errors can be effectively identified and separated.

Description

Technical Field

[0001] The present invention belongs to the technical field of engineering surveying, and in particular relates to a cross-river leveling method and system. Background Art

[0002] In the construction and operational monitoring of large-scale linear projects across rivers, accurately transferring elevation datums from one bank to the other—cross-river leveling—is a crucial foundational task. The accuracy of these measurements directly impacts the construction coordination and structural safety of key structures like bridges and tunnels.

[0003] Traditional cross-river leveling methods, such as direct leveling, are limited by the instrument's line of sight and cannot be used over wide waters. Therefore, trigonometric leveling has become the mainstream technology, typically using a total station to observe opposite sides of the river, inferring elevation differences by measuring vertical angles and slant distances. However, existing technologies have the following significant problems in practical application:

[0004] Asynchronous observation errors: Traditional trigonometric height measurement methods typically use a time-sharing and grouped approach, meaning one instrument first observes all target points on the opposite bank, followed by another instrument. Because atmospheric conditions (such as temperature, pressure, and humidity) change dynamically during observation, this asynchronous observation mode causes instruments on both sides to collect data at different times. This makes it impossible to effectively eliminate the effects of dynamic environmental errors such as atmospheric refraction and temperature gradients on height measurements, resulting in unstable measurement results and difficulty in ensuring accuracy.

[0005] Inadequate closure verification conditions: Traditional methods often use a single prism as the observation target. While geometric verification can be performed by constructing a quadrilateral loop, the verification dimension is limited. When systematic errors exist in the observation data, relying solely on geometric closure errors often makes it difficult to identify and isolate the problem, resulting in low data redundancy and insufficient reliability.

[0006] Low operational efficiency and automation: Traditional operational processes rely on manual record-keeping and require multiple round trips to achieve accuracy. This results in a cumbersome process, heavy fieldwork, and high time costs. This is especially true with the "double-line river crossing" approach (i.e., deploying two parallel observation routes), where the number of measurement points and workload increases exponentially.

[0007] Therefore, there is an urgent need for a new method and system for cross-river leveling that can overcome the above-mentioned defects and achieve high precision, high efficiency and high reliability. Summary of the Invention

[0008] Purpose of the invention: The purpose of the present invention is to provide a cross-river leveling method and system to address the deficiencies in the prior art, so as to solve the problems existing in the background technology such as large asynchronous observation errors, insufficient closure verification conditions and low operating efficiency.

[0009] Technical solution: The cross-river leveling method of the present invention comprises the following steps:

[0010] S1: Four control points are set on both sides of the water area to be measured to form a cross-river quadrilateral control network. A centering rod with upper and lower prisms is installed at each control point. Each centering rod is integrated with an upper prism and a lower prism with a preset fixed vertical spacing;

[0011] S2: setting up a first total station and a second total station on both sides of the water area;

[0012] S3: using the first total station and the second total station to synchronously and oppositely observe the upper prism and the lower prism on the centering pole tooling arranged on the opposite bank within a preset time synchronization error range to obtain vertical angle and slant distance data of each observation target;

[0013] S4: Based on the vertical angle and slant distance data, and using the preset fixed vertical spacing as a verification condition, the height difference between the target positions on both sides is calculated.

[0014] To further improve the above technical solution, the lengths of the two short sides of the cross-river quadrilateral control network are approximately equal, with a length difference of no more than 5%, and the first total station and the second total station are respectively set up near the midpoints of the short sides.

[0015] Furthermore, before starting the measurement, the following preparatory steps are also included: correcting the compensator, axis system errors of the horizontal axis and the vertical axis, and the automatic aiming error of the first total station and the second total station; and calibrating the preset fixed vertical spacing of the upper and lower prisms of each set of the centering rod tooling to ensure that the calibration error is no more than 0.5 mm.

[0016] Furthermore, the synchronous and opposite observation includes: a first observation period: the first total station and the second total station synchronously and oppositely observe the upper prisms of all centering pole tooling on the opposite bank; a second observation period: the first total station and the second total station synchronously and oppositely observe the lower prisms of all centering pole tooling on the opposite bank; the first observation period and the second observation period constitute a single-round observation.

[0017] Furthermore, it also includes exchanging the positions of the first total station, the second total station and the centering pole tooling on both sides, and repeating the synchronous and opposite observation steps to form a double-round observation.

[0018] Furthermore, the vertical angles of the prisms are obtained by synchronously and oppositely observing the upper prism and the lower prism of the four control points A, B, C, and D by the first total station and the second total station. and slant distance S; use the formula to calculate the initial value of the height difference of each section of the cross-river quadrilateral control network, including the height difference from point A to point B: , the height difference from point B to point C is , the height difference from point C to point D is , and the height difference from point D to point A is ;

[0019] The formula is: ; Where D is the horizontal distance, is a vertical angle , For instrument height, is the prism height, R is the radius of the earth, and k is the atmospheric refractive index;

[0020] The height difference of each section is algebraically summed along the closed loop to obtain the height closure difference. :

[0021] ;

[0022] Obtain the total length L of the closed loop and calculate the allowable limit of the elevation closure error using the following formula: :

[0023] ;

[0024] The accuracy is checked by using the loop closure error formed by the initial values ​​of the height differences of each segment, and the absolute value of the calculated height closure error is calculated. With the permissible limit For comparison, if , then the accuracy of the observation data is assessed to be qualified;

[0025] Exchange the positions of the first total station, the second total station and the centering pole tooling on both sides, and repeat the synchronous and opposite observation steps to form a double-round observation. Perform leveling network adjustment through adjustment software and output the most likely elevation values ​​of the four control points A, B, C, and D.

[0026] Furthermore, for each synchronous and opposite observation of the data of the upper and lower prisms of the same pair of centering pole tooling, the height difference observation value is calculated in real time and compared with the preset fixed vertical spacing. If the difference exceeds the preset limit, the observation data is marked as invalid or triggers re-measurement.

[0027] Furthermore, the first total station and the second total station are surveying robots with automatic target recognition function, and the synchronous and opposite observation steps are achieved by the surveying robots automatically searching, aiming and recording data.

[0028] The cross-river level monitoring system for implementing the above method comprises:

[0029] At least four centering rods are deployed on both sides of the water area to be measured to form a quadrilateral control network across the river. The centering rods are integrated with a pair of upper prisms and lower prisms, and a pre-calibrated fixed vertical spacing is set between the upper prisms and the lower prisms;

[0030] The first total station and the second total station are respectively deployed at the midpoint of the control points on both sides of the water area to be measured;

[0031] A data processing unit is configured to perform the following operations: control the first total station and the second total station to synchronously and oppositely observe the upper and lower prisms of the centering pole tooling arranged on the opposite bank, and receive observation data; use the fixed vertical spacing as a mandatory physical constraint condition to perform real-time verification on the received observation data, and based on the verified data, calculate the elevation transfer result between the two banks through leveling network adjustment.

[0032] Furthermore, the data processing unit is further configured to: before calculating the height difference, use the synchronously collected meteorological data to perform real-time meteorological correction on the observation data to eliminate the influence of atmospheric refraction on ranging.

[0033] Beneficial effects: Compared with the prior art, the advantages of the present invention are:

[0034] The present invention eliminates the asynchronous error caused by the dynamic change of atmospheric environment in real time by using the total station on both sides of the river to observe synchronously. At the same time, the innovative double-layer prism tooling introduces the physical forced closure check condition (fixed height difference). ), combined with the traditional quadrilateral geometric closure check, constitutes a "double closure" verification system, which greatly enhances data redundancy and reliability of results, and can effectively identify and separate systematic errors.

[0035] This invention utilizes a surveying robot equipped with Automatic Target Recognition (ATR) to automate the entire survey process, reducing manual intervention. A double-closure verification system enables a single-line river crossing to achieve or even exceed the accuracy of traditional dual-line river crossings, reducing field workload by approximately 50% and significantly shortening the time required for a single survey. This increased operational efficiency directly reduces labor and time costs. Furthermore, by optimizing the observation network and process, unnecessary repeated observations are reduced, further lowering the overall cost of the survey project. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the layout of the cross-river quadrilateral control network in an embodiment of the present invention.

[0037] Figure 2 Schematic diagram of the structure of the double-layer prism centering rod tooling in an embodiment of the present invention.

[0038] Figure 3 Schematic diagram of the structure of the detachable prism connector in an embodiment of the present invention.

[0039] Figure 4 is a schematic structural diagram of a prism in an embodiment of the present invention, Figure 4 (a) is the main view of the prism. Figure 4 Middle (b) is a side view of the prism.

[0040] Figure 5 is a schematic structural diagram of the prism rod in the present invention, Figure 5 (a) is the main view of the prism rod. Figure 5 Middle (b) is a side view of the prism rod.

[0041] The reference numerals in the figure are: 1, first total station; 2, second total station; 101, upper prism; 102, lower prism; 103, level bubble; 104, prism rod support frame; 105, lower prism centering rod; 1061, upper detachable connector; 1062, lower detachable connector. DETAILED DESCRIPTION

[0042] The technical solution of the present invention is described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the embodiments.

[0043] Example 1: The cross-river leveling point system provided by the present invention has a hardware architecture comprising:

[0044] Measuring equipment: Two Leica TM60 total stations (surveying robots), with a nominal angle measurement accuracy of ≤0.5″ and a distance measurement accuracy of 1mm+1×10-6D, equipped with an automatic target recognition (ATR) module;

[0045] Centering rod fixture: adopts double-layer prism structure, with fixed spacing between upper and lower prisms and height difference ≤0.5mm, forming closed observation conditions;

[0046] Layout of quadrilateral control network: 4 fixed piles are laid on both sides to form four control points A, B, C, and D. The difference in the length of the short side is ≤5%, which constitutes a forced closed observation condition.

[0047] 1. Preparation before observation and system calibration

[0048] Before conducting field observations, the following preparations and calibrations must be completed to ensure the accuracy and reliability of the measurement system:

[0049] 1.1 Total Station Calibration

[0050] The two Leica TM60 total stations (surveying robots) used in the present invention were subjected to comprehensive five-axis error correction, including: compensator zero point correction; horizontal axis tilt error compensation; vertical axis tilt error compensation; and automatic aiming error (ATR) calibration.

[0051] 1.2 Calibration of centering rod fixture

[0052] Accurately measure the fixed vertical spacing between the upper and lower prisms of each set of double-layer prism centering rod fixtures A two-level linear ruler is used for precise calibration to ensure that the height difference calibration accuracy is better than or equal to 0.5mm.

[0053] 1.3 Environmental parameter equipment preparation

[0054] Prepare high-precision environmental parameter collection equipment, including:

[0055] Temperature sensor: PT100 platinum resistance sensor is used to ensure the temperature measurement accuracy reaches ±0.5℃;

[0056] Barometer: Use digital barometer to ensure the pressure measurement accuracy reaches ±1.0hPa.

[0057] 1.4 Determination of the three correction parameters for slant range

[0058] In order to accurately correct the subsequent slant range observations, three correction parameters need to be determined in advance: meteorological correction model: use the Ciddor equation for meteorological correction; instrument additive constant: use the instrument factory calibration value; instrument multiplying constant: calibrate through the standard baseline field to obtain the actual multiplying constant correction value.

[0059] 2. Construction of cross-river control network

[0060] In the stable area on both sides of the river, a closed quadrilateral control network consisting of four control points A, B, C, and D is laid out, such as Figure 1 As shown. The control points are buried with stainless steel marker stakes. To ensure the strength of the observation pattern, the control network must meet the condition that the short side lengths are approximately equal.

[0061] 3. Synchronous observation and data collection of total station

[0062] This embodiment uses two total stations (the first total station 1 and the second total station 2) to perform synchronous observation. The complete single-round observation process is as follows:

[0063] 3.1 Observation at the first station (first total station 1):

[0064] Set up the first total station 1 at a survey station on the opposite bank (e.g., on the side of points C and D), which is located near the geometric midpoint of the CD line.

[0065] The first total station 1 first "learns" the upper prisms of the centering pole tooling at the four control points A, B, C, and D on the opposite bank in turn to establish an automatic aiming database.

[0066] Perform the full circle direction observation method. The first total station 1 automatically, sequentially, and multiple times (multiple rounds) observes the four upper prisms A, B, C, and D, and automatically records and stores the vertical angle in each direction. and slant distance S to the memory card.

[0067] After completing the observation of the upper prism, the first total station 1 relearns and measures all the lower prisms to complete the collection of double-level data.

[0068] 3.2 Observation at the second station (second total station 2):

[0069] Simultaneously, a second total station 2 is set up at a survey station on the local shore (e.g., on the side of points A and B), which is located near the geometric midpoint of the line AB.

[0070] The second total station 2 first synchronously learns and measures the lower prism of the centering pole tooling at the four control points A, B, C, and D.

[0071] Perform a full-circle direction observation method equivalent to the first total station 1 and record the observation data synchronously.

[0072] After completing the observation of the lower prism, the second total station 2 repeats the learning and measurement of all the upper prisms.

[0073] Through the above operations, the two total stations conducted complete observations of the upper and lower prisms of all measuring points in the same time period, and theoretically obtained the upper and lower height differences of the four centering rod prisms, forming redundant data that can be used for closure verification.

[0074] 4. Double-round observation plan

[0075] In order to meet the requirements of GB / T 12897-2006 "National First and Second Class Leveling Specifications" and eliminate instrument system errors, a double-round observation scheme is adopted:

[0076] Determine the number of observation rounds N: Determine the total number of observation rounds N based on the level requirements of cross-river leveling.

[0077] The first round of measurement: complete the complete observation process mentioned above.

[0078] Swap instruments and prisms: After completing the first single survey, swap the first total station 1 and the second total station 2 on both sides, and at the same time, swap the centering rod prism groups on both sides.

[0079] Second single round of observation: Repeat the observation process within the same period to complete the second single round of observation.

[0080] These two single rounds together constitute a complete double round observation.

[0081] In a single round of observation, the difference between the observation values ​​in each direction must meet the limit requirements, for example: the difference between four sighting readings of the same marking line is ≤3″; the difference between index differences is ≤8″; the difference between vertical angles of the same mark is ≤4″.

[0082] 5. Data adjustment and accuracy verification

[0083] Software Adjustment: Data processing was performed using the Leica TM60's built-in height adjustment software. This software incorporates correction models that account for external factors such as earth curvature, temperature, and atmospheric refraction during adjustment calculations. The software calculates the relative height differences between each measurement point.

[0084] Network adjustment solution: The entire leveling network is rigorously adjusted using the indirect adjustment method. The weight matrix is ​​dynamically allocated based on the number of observations and the dynamic changes in on-site meteorological conditions.

[0085] Accuracy assessment: Calculate the closed loop difference of the ABCD quadrilateral and the difference between each measurement round to make the final accuracy assessment.

[0086] Example 2: This example takes the high-precision elevation transmission of a highway-railway Yangtze River Bridge with a cross-river distance L=2.5km as an example.

[0087] In order to improve the accuracy of cross-river leveling and the work efficiency of surveyors, the present invention studies a method for measuring a cross-river leveling point system, using two Leica TM60 measuring robots to synchronously and oppositely observe the upper and lower prisms of the centering poles on both sides, automatically record the distance and vertical angle, and calculate the height difference respectively. During the measurement operation, when the cross-river leveling distance is not more than 300m, the instrument's line of sight should be 2m above the water surface, and when the distance is greater than 500m, it should be calculated accordingly; its line of sight vertical angle is not more than 3°, and the climatic environment conditions are cloudy, no rain, no fog, and no wind. This method can simultaneously obtain the height difference between the upper and lower layers of a prism, and is equivalent to using the full-circle observation method to observe the prism, increasing the closure condition to improve the measurement accuracy, and synchronous observation according to the specification eliminates the influence of atmospheric refraction, earth curvature, etc., thereby improving the observation accuracy. The instrument observes all centering pole prisms at the same time, which improves the measurement efficiency and is more advantageous than the previous observation of a single centering pole prism. Previous river crossing regulations often required a dual-line crossing. This method utilizes double-layer prism measurements and adds a closure condition, transforming the dual-line crossing into a single-line crossing, improving both accuracy and measurement efficiency. This method effectively eliminates the effects of the Earth's curvature and atmospheric refraction using the differential method. The elevation differences between the two instruments are averaged over multiple passes to determine the elevation difference between the two banks. The resulting measurements form a closed loop for leveling network adjustment calculations. This observation method is simple, efficient, highly accurate, requires multiple verification submissions, and features a high degree of automation, with data acquisition performed automatically by the instruments.

[0088] 1. System preparation and innovative tooling calibration

[0089] Before the observation, in addition to performing comprehensive five-axis error correction on the two Leica TM60 total stations, preparing high-precision temperature and pressure equipment, and determining the slant distance correction parameters, the core preparatory work of this method is to precisely calibrate the innovatively designed centering rod tooling.

[0090] Double prism centering rod fixture: This method uses a special double prism fixture. Figures 2 to 5 The tooling has an upper prism 101 and a lower prism 102 fixed on the same vertical prism rod. The bottom of the upper prism 101 is fixed above the lower prism centering rod 105 through an upper detachable connector 1061. The bottom of the lower prism 102 is fixed above the vertical rod body through a lower detachable connector 1062. The vertical rod body is supported by a prism rod support frame 104. A level bubble 103 is provided on the top of the vertical rod body.

[0091] The vertical distance between the centers of the upper prism 101 and the lower prism 102 is a fixed value that is precisely calibrated in advance. In this embodiment, the calibration is performed using a two-level linear ruler to ensure that The calibration error is no more than 0.5mm. This known, high-precision The value is the cornerstone of this method to achieve the physical closure constraint of "hierarchical mutual inspection" and is one of the key innovations that distinguishes it from the traditional single-layer prism method.

[0092] 2. Innovative observation network and synchronous observation mechanism

[0093] Network innovation - "single-line crossing the river" instead of "double-line crossing the river": This method uses an optimized "single-line crossing the river" quadrilateral control network (such as Figure 1 The 2018 GIS project (shown as points A, B, C, and D) replaced the traditional redundant "double-line crossing" network layout required to ensure accuracy. This simplified structure directly reduced field work by 50%. Its accuracy is guaranteed by the synchronized observation mechanism and double closure check system described below.

[0094] Synchronous Opposing Observation Mechanism: To address the atmospheric time-varying errors introduced by traditional asynchronous observations, this method establishes a rigorous synchronous observation mechanism. Total Station 1 (set up near the midpoint of CD) and Total Station 2 (set up near the midpoint of AB) are time-synchronized (synchronization error ≤ 1ms) and collect data at the same time (1Hz sampling rate) in opposite directions.

[0095] Parallel Control and Data Acquisition: Two instruments (0.5" angular measurement accuracy) synchronously perform target search (ATR accuracy ±0.3mm) and data acquisition. For example, while the first total station (1) observes the upper prism at point C, the second total station (2) simultaneously observes the upper prism at point A. This high degree of synchronization in the time domain maximizes the consistency of atmospheric conditions (especially the atmospheric refractive index k) along the observation paths of the instruments on both sides, laying the foundation for subsequent elimination of atmospheric effects and earth curvature errors through differential techniques.

[0096] 3. Data processing: a dual closed system integrating physical constraints and geometric verification

[0097] Data processing is the core link that reflects the innovation of this method, which integrates Physical closure check and geometric closure check based on quadrilateral rings.

[0098] Let the slope distance between the two points be S and the vertical angle be , the instrument height is i, the prism height is v, then the height difference formula between the two points is:

[0099] , horizontal distance The calculation formula is: ,but:

[0100] (1)

[0101] The surface of the earth is curved, and the elevation transfer between two points needs to be corrected for the earth's curvature. Let the radius of the earth be R and the horizontal distance be D, then the earth curvature correction term C is:

[0102] (2)

[0103] When light propagates in the air, it is affected by refraction. The atmospheric refraction correction term r is approximately k times the curvature effect (k is the atmospheric refraction coefficient, generally 0.08-0.15). The calculation formula is as follows:

[0104] (3)

[0105] Combining curvature and refraction correction, the corrected height difference formula is updated to:

[0106] (4)

[0107] Principle of opposite observation, in which, in the forward observation (A→B): the instrument is at point A, the prism is at point B, and the vertical angle , slope distance , the horizontal distance is: ; Reverse observation (B→A): the instrument is at point B, the prism is at point A, the vertical angle , slope distance , the horizontal distance is: .

[0108] Positive height difference:

[0109] Reverse height difference:

[0110] Ideally, ,Right now;

[0111]

[0112] (5)

[0113] Earth curvature and refraction correction: If ,but , the curvature and refractive error are offset. Instrument height and prism height error: If the accurate measurement 、 、 、 , the remaining error can be ignored.

[0114] Four points are arranged on both sides of the river to form a quadrilateral with approximately equal short sides. The instrument is set up at the midpoint of the short side to simultaneously observe the upper and lower prisms on the opposite bank.

[0115] Assume that the height difference of each side of the quadrilateral is , the closure error is:

[0116]

[0117] Closure tolerance for: (6)

[0118] For any total station (such as the first total station 1) observing any control point (such as point A), the height difference formula is updated to the following after integrating curvature and refraction correction:

[0119]

[0120] Where D is the horizontal distance, is the vertical angle, R is the radius of the earth, k is the atmospheric refraction coefficient, i is the instrument height, and v is the prism height.

[0121] Upper prism height difference: ;

[0122] Height difference of lower prism: ;

[0123] The height difference between the two should meet the following requirements:

[0124]

[0125] If the prism layer spacing is fixed ,but: , is the observation error term.

[0126] By enforcing the closure condition ( is known), the effects of atmospheric refraction and earth curvature can be separated.

[0127] This method calculates observations in real time during data processing and combines it with high-precision The difference directly reflects the combined effect of atmospheric refraction and earth curvature as well as random observation errors. By setting a dynamic limit, such as (S is the slope distance), if , then re-measurement is automatically triggered. Based on the forced closure conditions of known physical quantities, data quality can be monitored in real time and dynamically, and it is possible to separate system errors.

[0128] 3.2 Quadrilateral ring closure error

[0129] After passing the hierarchical mutual check, geometric check is performed.

[0130] Height difference calculation: The two-way observation difference method is used to calculate the height difference of each river bank, as shown in formula (5). This method can effectively eliminate most of the system errors. Finally, a simplified formula for calculating the height difference across the river is obtained, which eliminates most of the error terms:

[0131] (7)

[0132] The short sides of the quadrilateral are approximately equal. , the curvature refraction term cancels out; the instrument height and prism height are accurately measured, and the error term is eliminated.

[0133] Closure error calculation: Calculate the elevation closure error of the quadrilateral loop A→B→C→D→A:

[0134]

[0135] The closing difference The absolute value is compared with the specification limit of second-class leveling measurement. For this embodiment, the total length L of the closed loop is: ,but Only when Only when the accuracy of the entire network is considered qualified.

[0136] 3.3 Strict adjustment

[0137] Finally, all valid observation data that passed the double check (including double-round observation data) were put into a weighted least squares adjustment model to calculate the most probable elevation values ​​of the four control points A, B, C, and D. In multiple applications of this embodiment, the mean error of the elevation difference of 2.5 km across the river can be controlled to ≤±1 mm, fully meeting the requirements of second-class leveling.

[0138] Table 1 Comparison between the present invention and prior art

[0139] Comparison Dimension Previous technology The present invention Prism structure Single-layer prism (4 independent prisms) Double-layer prism fixture (the distance between the upper and lower layers is fixed ≤ 0.5mm, and the double prisms at the same measuring point form a forced closing condition) Observation mechanism Instruments on both sides of the strait simultaneously observe the single-layer prism on the other side Four target points × two-level synchronous observation: instruments on each bank simultaneously collect upper and lower prism data from four measuring points on both sides of the bank Error cancellation logic Eliminate spherical aberration by relying on quadrilateral geometric difference (Formula 5) New layer mutual inspection: dynamic verification data of the mutual difference limit of the upper and lower layers, automatic re-measurement when exceeding the limit Closure conditions Single quadrilateral closed loop Double closure system: Quadrilateral ring closure difference; upper and lower level height difference closure difference Network design Double-line river crossing (8 measuring points required) Single-line river crossing: Only 4 measuring points + double-layer prism are required, reducing field work by 50%

[0140] The present invention constitutes a complete, efficient and high-precision cross-river leveling solution through innovative double-layer prism tooling, optimized single-line network, strict synchronous observation mechanism and a double closure verification system that integrates physical and geometric constraints.

[0141] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the present invention itself. Various changes may be made to it in form and detail without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. A cross-river leveling method, characterized in that: The following steps are involved: S1: Four control points are set on both sides of the water area to be measured to form a cross-river quadrilateral control network. A centering rod with upper and lower prisms is installed at each control point. Each centering rod is integrated with an upper prism and a lower prism with a preset fixed vertical spacing; S2: setting up a first total station and a second total station on both sides of the water area; S3: using the first total station and the second total station to synchronously and oppositely observe the upper prism and the lower prism on the centering pole tooling arranged on the opposite bank within a preset time synchronization error range to obtain vertical angle and slant distance data of each observation target; S4: Based on the vertical angle and slant distance data, and using the preset fixed vertical spacing as a verification condition, the height difference between the target positions on both sides is calculated.

2. The cross-river leveling method according to claim 1, characterized in that: The lengths of the two short sides of the cross-river quadrilateral control network are approximately equal, with a length difference of no more than 5%, and the first total station and the second total station are respectively set up near the midpoints of the short sides.

3. The cross-river leveling method according to claim 1, characterized in that: Before starting the measurement, the following preparatory steps are also included: correcting the compensator, horizontal axis and vertical axis axis errors and automatic aiming errors of the first total station and the second total station; and calibrating the preset fixed vertical spacing of the upper and lower prisms of each set of the centering rod tooling to ensure that the calibration error is no more than 0.5 mm.

4. The cross-river leveling method according to claim 1, characterized in that: The synchronous and opposite ground observation includes: First observation period: the first and second total stations synchronously observe the upper prisms of all centering pole fixtures on the opposite bank; Second observation period: the first and second total stations synchronously observe the lower prisms of all centering pole fixtures on the opposite bank; The first observation period and the second observation period constitute a single round of observation.

5. The cross-river leveling method according to claim 4, characterized in that: The method also includes exchanging the positions of the first total station, the second total station and the centering pole tooling on both sides, and repeating the synchronous and opposite observation steps to form a double-round observation.

6. The cross-river leveling method according to claim 1, characterized in that: Step S4 includes: The vertical angles of each prism are obtained by synchronously and oppositely observing the upper prism and lower prism of the four control points A, B, C, and D by the first total station and the second total station. and slant distance S; use the formula to calculate the initial value of the height difference of each section of the cross-river quadrilateral control network, including the height difference from point A to point B: , the height difference from point B to point C is , the height difference from point C to point D is , and the height difference from point D to point A is ; The formula is: ;in, , is the slope distance, is a vertical angle, For instrument height, is the prism height, R is the radius of the earth, and k is the atmospheric refractive index; The height difference of each section is algebraically summed along the closed loop to obtain the height closure difference. : ； Obtain the total length L of the closed loop and calculate the allowable limit of the elevation closure error using the following formula: : ； The accuracy is checked by using the loop closure error formed by the initial values ​​of the height differences of each segment, and the absolute value of the calculated height closure error is calculated. With the permissible limit For comparison, if , then the accuracy of the observation data is assessed to be qualified; Exchange the positions of the first total station, the second total station and the centering pole tooling on both sides, and repeat the synchronous and opposite observation steps to form a double-round observation. Perform leveling network adjustment through adjustment software and output the most likely elevation values ​​of the four control points A, B, C, and D.

7. The cross-river leveling method according to claim 1, characterized in that: For each synchronous and opposite observation of the data of the upper prism and the lower prism of the same pair of centering pole tooling, the height difference observation value is calculated in real time and compared with the preset fixed vertical spacing. If the difference exceeds the preset limit, the observation data is marked as invalid or triggers re-measurement.

8. The cross-river leveling method according to claim 1, characterized in that: The first total station and the second total station are surveying robots with automatic target recognition functions, and the synchronous and opposite observation steps are achieved by the surveying robots automatically searching, aiming and recording data.

9. A system for implementing the cross-river leveling method according to claim 1, characterized in that: include: At least four centering rods are deployed on both sides of the water area to be measured to form a quadrilateral control network across the river. The centering rods are integrated with a pair of upper prisms and lower prisms, and a pre-calibrated fixed vertical spacing is set between the upper prisms and the lower prisms; The first total station and the second total station are respectively deployed at the midpoint of the control points on both sides of the water area to be measured; A data processing unit is configured to perform the following operations: control the first total station and the second total station to synchronously and oppositely observe the upper and lower prisms of the centering pole tooling arranged on the opposite bank, and receive observation data; use the fixed vertical spacing as a mandatory physical constraint condition to perform real-time verification on the received observation data, and based on the verified data, calculate the elevation transfer result between the two banks through leveling network adjustment.

10. The system according to claim 9, characterized in that The data processing unit is further configured to: before calculating the height difference, use the synchronously collected meteorological data to perform real-time meteorological correction on the observation data to eliminate the influence of atmospheric refraction on ranging.

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