Optimal Calculation Method for Line Length between Large-Span Tower Poles in Difficult Areas

Abstract

The present invention belongs to the technical field of length measurement, and discloses an optimal calculation method for the length of the line between large-span tower poles in difficult areas. When accurately calculating the length of the line between large-span tower poles in difficult areas, the optimal calculation method for the length of the line between large-span tower poles in the present invention does not require setting up a prism or a reflector at the point to be determined for distance measurement. Only the horizontal direction value and the zenith angle need to be read by aiming at the same target, and the three-dimensional coordinates of the point to be determined are obtained by resection with angle and distance, so as to accurately obtain the length of the line between the tower poles. While ensuring the accuracy of the calculation result, the present invention simplifies the calculation process, improves the efficiency, and saves engineering costs.

Description

Technical Field

[0001] The present invention belongs to the technical field of length measurement, and particularly relates to an optimal calculation method for the length of the line between large-span tower poles in difficult areas. Background Art

[0002] Before the bidding stage, in order to make the engineering quantity of the wire length between tower poles relatively accurate, a design unit is usually invited to carry out line planning and design (design on a topographic map / image map). Generally, due to inaccurate design, a large error will occur in calculating the length of the line between tower poles, resulting in economic losses. Similarly, during the construction preparation stage, the construction unit also needs to accurately determine the wire length between tower poles to facilitate accurately determining the length of the wire to be purchased, avoiding wire waste during later construction, and saving project costs. The above problems generally occur when calculating the length of the line between tower poles, and it is even more prominent and important to calculate the length of the line between large-span tower poles in difficult areas.

[0003] In summary, it is urgent to find an optimal calculation method for the length of the line between large-span tower poles in difficult areas to solve the above problems. Summary of the Invention

[0004] The purpose of the present invention is to provide an optimal calculation method for the length of the line between large-span tower poles in difficult areas. When accurately calculating the length of the line between large-span tower poles in difficult areas, there is no need to set up a prism or reflector at the point to be determined for distance measurement. Only the horizontal direction value and the zenith angle need to be read by aiming at the same target, and the three-dimensional coordinates of the point to be determined are obtained by resection with angle and distance, and then the length of the line between the tower poles is accurately obtained. While ensuring the accuracy of the calculation result, the present invention simplifies the calculation process, improves efficiency, and saves project costs.

[0005] The technical solution adopted by the present invention is an optimal calculation method for the length of the line between large-span tower poles in difficult areas, including the following steps:

[0006] S1. Select two points, namely point A and point B, within a certain range outside the area where the length of the tower pole line needs to be calculated. Among them, point A and point B need to meet the following conditions: point A and point B can see each other; at point A and point B, the highest objects C and D at the positions where the tower poles need to be installed can be seen, denoted as target point C and target point D;

[0007] S2. Establish a plane construction independent coordinate system with point A and point B as the X-axis and the line perpendicular to side AB as the Y-axis, and measure the coordinates of point A and point B as known points. Then, calculate the distance L of side AB according to the inverse coordinate calculation AB and the azimuth angle F of side AB AB ;

[0008] Taking point A and point B as the X-axis and the direction perpendicular to side AB as the Y-axis, a plane construction independent coordinate system is established. Assume the coordinates of point A are (0, 0, 1000) and the azimuth angle F of side AB AB = 0°00′00″. The coordinates of point B measured by the instrument are (X B , Y B , H B ). Through coordinate inverse calculation, the distance L of side AB AB and the azimuth angle F of side AB AB are obtained as follows:

[0009]

[0010]

[0011] where X B is the X-axis coordinate of point B; X A is the X-axis coordinate of point A; Y B is the Y-axis coordinate of point B; Y A is the Y-axis coordinate of point A; is the angle obtained by coordinate inverse calculation;

[0012] When and is in the first quadrant, the azimuth angle at this time;

[0013] When and is in the second quadrant, the azimuth angle at this time;

[0014] When and is in the third quadrant, the azimuth angle at this time;

[0015] When and is in the fourth quadrant, the azimuth angle at this time;

[0016] When and is on the positive half-axis of the X-axis, the azimuth angle at this time;

[0017] When and is on the negative half-axis of the X-axis, the azimuth angle at this time;

[0018]

[0019] where F BA is the azimuth angle of side BA; F ABis the azimuth of side AB;

[0020] When the following formula holds, take the "-" sign; when the following formula holds, take the "+" sign; when the following formula holds ;

[0021] When the line turning angle is a left angle:

[0022] F NP = F MN + left angle - 180°

[0023] where F NP is the azimuth from N to P; F MN is the azimuth from M to N;

[0024] When the line turning angle is a right angle:

[0025] F NP = F MN - right angle + 180°

[0026] where F NP is the azimuth from N to P; F MN is the azimuth from M to N;

[0027] S3. Set up the total station at point A, and set the horizontal direction value FX AB of side AB to 0°00′00″. Observe the highest objects C and D at the tower pole positions respectively to obtain the horizontal direction value FX AC′ of side AC′, the horizontal direction value FX AD′ of side AD′, and the zenith angles ∠TAC of side AC and ∠TAD of side AD; Set up the total station at point B, and set the horizontal direction value FX BA of side BA to 0°00′00″. Observe the highest objects C and D at the tower pole positions respectively to obtain the horizontal direction value FX BC′ of side BC′, the horizontal direction value FX BD′ of side BD′, and the zenith angles ∠TBC of side BC and ∠TBD of side BD;

[0028] S4. According to the distance L AB of side AB and the azimuth F AB of side AB calculated in S2, calculate the distances L AC′ of sides AC′, AD′, BC′, BD′ according to the sine theorem AD′ 、L BC′ 、L BD′ ;

[0029] S5. According to the distance L of side AB calculated in S2AB and the azimuth F of side AB AB and the horizontal direction value FX obtained by observation in S3 AC′ , FX AD′ , FX BC′ , FX BD′ , according to the azimuth calculation principle, obtain the azimuths F of sides AC′, AD′, BC′, and BD′ AC′ , F AD′ , F BC′ , F BD′ ;

[0030] S6. From the distances L of sides AC′, AD′, BC′, and BD′ calculated in S4 AC′ , L AD′ , L BC′ , L BD′ and the azimuths F of sides AC′, AD′, BC′, and BD′ calculated in S5 AC′ , F AD′ , F BC′ , F BD′ and the plane coordinates of known point A and known point B, calculate the plane coordinates of target point C and target point D according to the forward calculation of coordinates;

[0031] S7. From the zenith angles ∠TAC, ∠TAD, ∠TBC, and ∠TBD of the highest objects C and D at the observed tower pole positions in S3 and the distances L of sides AC′, AD′, BC′, and BD′ calculated in S4 AC′ , L AD′ , L BC′ , L BD′ and the elevations of known point A and known point B, calculate the elevation H of target point C C and the elevation H of target point D D ;

[0032] S8. Adjust the plane coordinates and elevations of target point C and target point D calculated in S6 and S7 to obtain the three-dimensional coordinates of target point C and target point D;

[0033] S9. Calculate the length L of CD by the spatial distance formula CD .

[0034] Furthermore, in S1, select two points, namely point A and point B, within a certain range outside the area where the tower pole line length needs to be calculated. When making coordinate assumptions and on-site selections, it is necessary to ensure that point A and point B can see each other, and at the same time, it is also necessary to ensure that when setting up the instrument at point A, target point C and target point D can be clearly seen, and when setting up the instrument at point B, target point C and target point D can also be clearly seen.

[0035] Further, in S3, according to the horizontal direction values FX of the observed target points C and D AC′ , FX AD′ , FX BC′ , FX BD′ , the interior angles in △BAC′ and △ABD′ are obtained: ∠BAC′, ∠BAD′, ∠ABC′, ∠ABD′;

[0036] According to the triangle interior angle sum theorem of 180°, the angles corresponding to side AB are calculated: ∠AC′B, ∠AD′B, and the calculation formulas are:

[0037] ∠AC′B = 180° - (∠BAC′ + ∠ABC′)

[0038] ∠AD′B = 180° - (∠BAD′ + ∠ABD′).

[0039] Further, in S4, according to the sine theorem, the distances L of sides AC′, AD′, BC′, and BD′ are calculated AC′ , L AD′ , L BC′ , L BD′ , and the calculation formulas are:

[0040]

[0041] where L AB is the distance of side AB; ∠AC′B is the angle corresponding to side AB; ∠ABC′ is the angle corresponding to side AC′;

[0042] Similarly, the distances L of sides AD′, BC′, and BD′ are obtained AD′ , L BC′ , L BD′ .

[0043] Further, in S5, according to the azimuth calculation principle, the azimuths F of sides AC′, AD′, BC′, and BD′ are obtained AC′ , F AD′ , F BC′ , F BD′ , and the calculation formulas are:

[0044] F AC′ = F BA - ∠BAC′ + 180°

[0045] F AD′ = F BA - ∠BAD′ + 180°

[0046] F BC′ = F AB - ∠ABC′ - 180°

[0047] F BD′ = F AB - ∠ABD′ - 180°

[0048] Wherein, F AB is the azimuth of side AB; F BA is the azimuth of side BA; ∠BAC′, ∠BAD′, ∠ABC′, ∠ABD′ are turning angles.

[0049] Further, in the step S6, the plane coordinates of the target point C are calculated according to the forward calculation of coordinates, and the calculation formula is:

[0050]

[0051] Wherein, X A is the X-axis coordinate of point A; Y A is the Y-axis coordinate of point A; F AC′ is the azimuth of side AC′; L AC′ is the distance of side AC′;

[0052] Similarly, the plane coordinates (X D , Y D ) of the target point D are obtained.

[0053] Further, in the step S7, the elevation of the target point C is calculated according to the trigonometric function relationship, and the calculation formula is:

[0054]

[0055] Wherein, H A is the elevation of point A; L AC′ is the distance of side AC′; ∠TAC is the zenith angle observed at point A when the total station is set up at point A to the target point C;

[0056] Similarly, the elevation H D of the target point D is obtained.

[0057] Further, in the step S8, the plane coordinates and elevations of the target points C and D calculated in S6 and S7 are adjusted, and finally the target points C (X C , Y C , H C ) and the target point D (X D , Y D , H D ) are obtained.

[0058] Further, in the step S9, the length L CD of CD is calculated by the spatial distance formula, and the calculation formula is:

[0059]

[0060] Among them, X C is the X-axis coordinate of the target point C; X D is the X-axis coordinate of the target point D; Y C is the Y-axis coordinate of the target point C; Y D is the Y-axis coordinate of the target point D; H C is the elevation of the target point C; H D is the elevation of the target point D.

[0061] The beneficial effects of the present invention are as follows: When accurately calculating the line length between large-span tower poles in a difficult area, there is no need to set up a prism or reflector at the point to be determined for distance measurement. Only by aiming at the same target and reading the horizontal direction value and zenith angle, the three-dimensional coordinates of the point to be determined can be obtained through resection with angles and sides, and then the line length between the tower poles can be accurately obtained. While ensuring the accuracy of the calculation results, the present invention simplifies the calculation process, improves efficiency, and saves engineering costs. Description of the Drawings

[0062] Figure 1 is a flowchart of the optimal calculation method for the line length between large-span tower poles in a difficult area.

[0063] Figure 2 is an elevation view of the optimal calculation method for the line length between large-span tower poles in a difficult area.

[0064] Figure 3 is a plan view of the optimal calculation method for the line length between large-span tower poles in a difficult area.

[0065] Figure 4 is an elevation view when observing at the assumed point A of the instrument.

[0066] Figure 5 is an elevation view when observing at the assumed point B of the instrument.

[0067] Figure 6 is a schematic diagram of the left / right angle of the line.

[0068] Among them, for the convenience of calculation, the definitions of the various parameters in the above figure are as follows: Assume that the point A(X A , Y A , H A ) is the coordinate origin, the azimuth angle F AB = 0°00′00″ of the direction of the side AB is the X-axis, the Y-axis is perpendicular to the X-axis in the plane, and the H-axis is perpendicular to both the X-axis and the Y-axis at the same time, establishing a construction coordinate system; the coordinate of the point B where the instrument is set is (X B , Y B , H B ); the vertical projection of the target point C is C′; the vertical projection of the target point D is D′; the height difference from the point C to the plane of AB is h AC; The elevation difference from point D to line AB is h BD ; The distances from the sides AC′, AD′, BC′, and BD′ are respectively L AC′ , L AD′ , L BC′ , L BD′ ; The azimuth angles of the sides AC′, AD′, BC′, and BD′ are respectively F AC′ , F AD′ , F BC′ , F BD′ ; The horizontal direction values of observing point B, point C, and point D at point A are respectively FX AB , FX AC′ , FX AD′ ; The horizontal direction values of observing point A, point C, and point D at point B are respectively FX BA , FX BC′ , FX BD′ ; The zenith angles of observing point C and point D at point A are ∠TAC and ∠TAD; The zenith angles of observing point C and point D at point B are ∠TBC and ∠TBD; The coordinates of the point to be determined (target point) C and the point to be determined (target point) D are (X C , Y C , H C ) and (X D , Y D , H D ); The spatial distance of CD is L CD . Detailed implementation manner

[0069] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and embodiments.

[0070] The optimal calculation method for the line length between large-span tower poles in difficult areas described in the present invention, as Figure 1 shown, includes the following steps:

[0071] S1. Select two points, namely point A and point B, within a certain range outside the area where the line length of the tower pole needs to be calculated. Among them, point A and point B need to meet the following conditions: Point A and point B can see each other; At both point A and point B, the highest objects (targets) C and D at the positions where the tower poles need to be installed can be seen, and they are set as target point C and target point D.

[0072] Select two points, namely point A and point B, within a certain range outside the area where the line length of the tower pole needs to be calculated. For the convenience of calculation, when making coordinate assumptions and on-site selections, as Figure 2As shown, it should be ensured that point A and point B can see each other. At the same time, it should also be ensured that when setting up the instrument at point A, the target points C and D can be clearly seen, and when setting up the instrument at point B, the target points C and D can also be clearly seen.

[0073] S2. Establish an independent plane construction coordinate system with point A and point B as the X-axis and the direction perpendicular to side AB as the Y-axis. Measure the coordinates of point A and point B as known points, and then calculate the distance L of side AB according to the inverse coordinate calculation. AB and the azimuth angle F of side AB AB .

[0074] Establish an independent plane construction coordinate system with point A and point B as the X-axis and the direction perpendicular to side AB as the Y-axis. Assume the coordinates of point A are (0, 0, 1000), and the azimuth angle of side AB is F AB = 0°00′00″. The coordinates of point B where the instrument is set up are (X B , Y B , H B ). Through inverse coordinate calculation, the distance L of side AB AB , the azimuth angle F of side AB (BA) AB (F BA ) are obtained:

[0075] Formula 1

[0076] Formula 2

[0077] Among them, X B is the X-axis coordinate of point B; X A is the X-axis coordinate of point A; Y B is the Y-axis coordinate of point B; Y A is the Y-axis coordinate of point A; is the angle obtained by inverse coordinate calculation;

[0078] When and is in the first quadrant, at this time the deflection angle (azimuth angle) ;

[0079] When and is in the second quadrant, at this time the deflection angle (azimuth angle) ;

[0080] When and is in the third quadrant, at this time the deflection angle (azimuth angle) ;

[0081] When and is in the fourth quadrant, at this time the deflection angle (azimuth angle) ;

[0082] When and it is located on the positive semi - axis of the X - axis. At this time, the deflection angle (azimuth angle) ;

[0083] When and it is located on the negative semi - axis of the X - axis. At this time, the deflection angle (azimuth angle) ;

[0084] Formula 3

[0085] where, F BA is the azimuth angle of side BA; F AB is the azimuth angle of side AB;

[0086] When in the above formula take the "-" sign; when in the above formula take the "+" sign; when in the above formula at this time ;

[0087] When the line turning angle is a left - hand angle (let the line forward direction be M→N→P, and the left - hand angle is defined as the turning angle (0° - 360°) located on the left side of the line along the line forward direction, see Figure 6 ):

[0088] F NP =F MN + left - hand angle - 180° Formula 4

[0089] where, F NP is the azimuth angle of N→P; F MN is the azimuth angle of M→N;

[0090] When the line turning angle is a right - hand angle (let the line forward direction be M→N→P, and the right - hand angle is defined as the turning angle (0° - 360°) located on the right side of the line along the line forward direction, see Figure 6 ):

[0091] F NP =F MN - right - hand angle + 180° Formula 5

[0092] where, F NP is the azimuth angle of N→P; F MN is the azimuth angle of M→N.

[0093] S3. Set up the total station at point A, and observe the highest objects (targets) C and D at the tower pole position respectively, obtaining the horizontal direction value FX AC′ of side AC′, the horizontal direction value FX AD′and the zenith angles ∠TAC of side AC and ∠TAD of side AD; Set up the total station at point B, and observe the highest objects (targets) C and D at the position of the tower pole respectively to obtain the horizontal direction value FX of side BC′ BC′ and the horizontal direction value FX of side BD′ BD′ as well as the zenith angles ∠TBC of side BC and ∠TBD of side BD.

[0094] As Figure 3 , Figure 4 shown, set up the total station instrument at point A, and set the horizontal direction value FX of side AB AB to 0°00′00″, and observe target point C and target point D respectively: the horizontal direction value of target point C is FX AC′ and the zenith angle is ∠TAC, the horizontal direction value of target point D is FX AD′ and the zenith angle is ∠TAD;

[0095] As Figure 3 , Figure 5 shown, set up the total station instrument at point B, and set the horizontal direction value FX of side BA BA to 0°00′00″, and observe target point C and target point D respectively: the horizontal direction value of target point C is FX BC′ and the zenith angle is ∠TBC, the horizontal direction value of target point D is FX BD′ and the zenith angle is ∠TBD;

[0096] As Figure 3 shown, according to the observed horizontal direction values FX AC′ and FX AD′ and FX BC′ and FX BD′ of target point C and target point D, the interior angles (deflection angles) in △BAC′ and △ABD′ can be obtained: ∠BAC′, ∠BAD′, ∠ABC′, ∠ABD′;

[0097] As Figure 3 shown, according to the theorem of the sum of interior angles of a triangle being 180°, the angles corresponding to side AB can be calculated: ∠AC′B, ∠AD′B, see Formula 6 and Formula 7:

[0098] ∠AC′B = 180° - (∠BAC′ + ∠ABC′) Formula 6

[0099] ∠AD′B = 180° - (∠BAD′ + ∠ABD′) Formula 7.

[0100] S4. From the distance L AB of side AB calculated in S2 AB, calculate the distances \(L\) of the sides \(AC'\), \(AD'\), \(BC'\), and \(BD'\) according to the sine theorem AC′ , \(L\) AD′ , \(L\) BC′ , \(L\) BD′ .

[0101] As Figure 3 shown, the distances \(L\) of the sides \(AC'\), \(AD'\), \(BC'\), and \(BD'\) can be calculated according to the sine theorem AC′ , \(L\) AD′ , \(L\) BC′ , \(L\) BD′ , and the calculation formula is:

[0102] Formula 8

[0103] where \(\angle ABC'\) is the angle corresponding to the side \(AC'\);

[0104] Similarly, the distances \(L\) of the sides \(AD'\), \(BC'\), and \(BD'\) can be obtained AD′ , \(L\) BC′ , \(L\) BD′ .

[0105] S5. From the distance \(L\) of the side \(AB\) calculated in S2 AB and the azimuth angle \(F\) of the side \(AB\) AB and the direction values \(FX\) observed in S3 AC′ , \(FX\) AD′ , \(FX\) BC′ , \(FX\) BD′ , the azimuth angles \(F\) of the sides \(AC'\), \(AD'\), \(BC'\), and \(BD'\) are obtained according to the azimuth angle calculation principle AC′ , \(F\) AD′ , \(F\) BC′ , \(F\) BD′ .

[0106] As Figure 3 shown, the azimuth angles \(F\) of the sides \(AC'\), \(AD'\), \(BC'\), and \(BD'\) can be obtained according to Formula 4 and Formula 5 AC′ , \(F\) AD′ , \(F\) BC′ , \(F\) BD′ , and the calculation formula is:

[0107] F AC′ = F BA - \(\angle BAC'\) + 180° Formula 9

[0108] F AD′ = F BA - \(\angle BAD'\) + 180° Formula 10

[0109] F BC′ = F AB-∠ABC′ - 180° Formula 11

[0110] F BD′ = F AB -∠ABD′ - 180° Formula 12.

[0111] S6. The distances L AC′ , L AD′ , L BC′ , L BD′ of the sides AC′, AD′, BC′, BD′ calculated in S4 and the azimuth angles F AC′ , F AD′ , F BC′ , F BD′ of the sides AC′, AD′, BC′, BD′ calculated in S5, as well as the plane coordinates of the known point A and the known point B. Calculate the plane coordinates of the target points C and D according to the forward calculation of coordinates.

[0112] Calculate the plane coordinates of the target point C by the forward calculation of coordinates. The calculation formula is:[[]]

[0113] Formula 13

[0114] Similarly, obtain the plane coordinates (X D , Y D ) of the target point D.

[0115] S7. The zenith angles of C and D observed in S3 and the distances L AC′ , L AD′ , L BC′ , L BD′ of the sides AC′, AD′, BC′, BD′ calculated in S4, as well as the elevations of the known point A and the known point B. Calculate the elevation H C of the target point C and the elevation H D of the target point D according to the trigonometric function relationship.

[0116] Calculate the elevation of the target point C according to the trigonometric function relationship. The calculation formula is:[[]]

[0117] Formula 14

[0118] where H A is the H-axis coordinate (elevation of point A);

[0119] Similarly, the elevation H D of the target point D can be obtained.

[0120] S8. Adjust the plane coordinates and elevations of the target points C and D calculated in S6 and S7 to obtain the three-dimensional coordinates of the target points C and D.

[0121] Adjust the plane coordinates and elevations of the target points C and D calculated in S6 and S7, and finally obtain the target point C(X C , Y C , H C ) and the target point D(X D , Y D , H D ).

[0122] S9. Calculate the length L of CD by the spatial distance formula CD , and the calculation formula is:

[0123] Formula 15.

[0124] The following further verifies and illustrates the present invention in combination with a specific embodiment.

[0125] This example uses a certain engineering project. The project is located deep in the high mountains and dense forests. It is necessary to erect high-voltage lines in this environment. In order to save project costs, it is necessary to accurately calculate the length of the wire between two tower poles.

[0126] Assume the coordinate point A(0, 0, 1000), the backsight point B, and solve for the coordinate point B(0, 542.2778, 1020.356). Taking point A and point B as known points, combined with Figures 1 to 6 and calculation formulas 1 to 15, the calculation results are shown in Tables 1 to 8 below:

[0127] Table 1 Table of known point conditions

[0128]

[0129] Table 2 Table of observed angles

[0130]

[0131] Table 3 Table of calculated interior angle results

[0132]

[0133] Table 4 Table of calculated point-to-point horizontal distances

[0134]

[0135] Table 5 Table of calculated azimuths between two points

[0136]

[0137] Table 6 Table of calculated coordinates

[0138]

[0139] Table 7 Coordinate Adjustment Result Table

[0140]

[0141] Table 8 Spatial Distance Table between Target Points C and D

[0142]

[0143] From the data analysis results in the above embodiment tables, it can be concluded that:

[0144] When accurately calculating the line length between large-span tower poles in difficult areas, the present invention does not require setting up a prism or reflector at the point to be determined for distance measurement. It only needs to aim at the same target to read the horizontal direction value and zenith angle, and obtain the three-dimensional coordinates of the point to be determined through resection with angles and sides, and then accurately obtain the line length between the tower poles. While ensuring the accuracy of the calculation results, the present invention simplifies the calculation process, improves efficiency, saves engineering costs, and provides certain technical support for power construction.

[0145] The content not described in detail in the specification of the present invention belongs to the prior art in the technical field.

Claims

1. Optimal calculation method for the line length between large-span tower poles in difficult areas, characterized in that, Including the following steps: S1. Select two points, namely point A and point B, within a certain range outside the area of the tower pole line length to be calculated. Among them, point A and point B need to meet the following conditions: Point A and point B can see each other; at both point A and point B, the highest objects C and D at the position where the tower pole needs to be installed can be seen, designated as target point C and target point D; S2. Establish an independent plane construction coordinate system with point A and point B as the X-axis and the line perpendicular to side AB as the Y-axis. Measure the coordinates of point A and point B as known points, and then calculate the distance L of side AB and the azimuth F of side AB according to the inverse coordinate calculation. AB and the azimuth F of side AB AB ; Taking point A and point B as the X-axis and the direction perpendicular to side AB as the Y-axis, a plane construction independent coordinate system is established. Assume the coordinates of point A are (0, 0, 1000) and the azimuth angle F of side AB AB = 0°00′00″. The coordinates of point B measured by the instrument are (X B , Y B , H B ). Through coordinate inverse calculation, the distance L of side AB AB and the azimuth angle F of side AB AB are obtained as follows: Among them, X B is the X-axis coordinate of point B; X A is the X-axis coordinate of point A; Y B is the Y-axis coordinate of point B; Y A is the Y-axis coordinate of point A; is the angle obtained by inverse coordinate calculation; When and is in the first quadrant, and at this time the azimuth angle ; When and is in the second quadrant, and at this time the azimuth angle ; When and is in the third quadrant, and at this time the azimuth angle ; When and is in the fourth quadrant, and at this time the azimuth angle ; When and it is on the positive half-axis of the X-axis, and at this time the azimuth angle ; When and it is located on the negative semi-axis of the X-axis. At this time, the azimuth angle ; Among them, F BA is the azimuth of side BA; F AB is the azimuth of side AB; When in the above formula take the "-" sign; when in the above formula take the "+" sign; when in the above formula at that time ; When the line turning angle is a left angle: F NP = F MN + Left corner - 180° Among them, F NP is the azimuth from N to P; F MN is the azimuth from M to N; When the line turning angle is a right angle: F NP = F MN - Right angle + 180° Among them, F NP is the azimuth from N to P; F MN is the azimuth from M to N; S3. Set up the total station at point A, and set the horizontal direction value FX of side AB AB to 0°00′00″. Observe the tallest objects C and D at the position of the tower pole respectively, and obtain the horizontal direction value FX of side AC′ AC′ , the horizontal direction value FX of side AD′ AD′ and the zenith angles ∠TAC of side AC and ∠TAD of side AD; Set up the total station at point B, and set the horizontal direction value FX of side BA BA to 0°00′00″. Observe the tallest objects C and D at the position of the tower pole respectively, and obtain the horizontal direction value FX of side BC′ BC′ , the horizontal direction value FX of side BD′ BD′ and the zenith angles ∠TBC of side BC and ∠TBD of side BD; S4. The distance L of side AB calculated from S2 AB and the azimuth angle F of side AB AB . Calculate the distances L of sides AC′, AD′, BC′, and BD′ according to the sine theorem AC′ , L AD′ , L BC′ , L BD′ ; S5, the distance L of side AB calculated in S2 AB and the azimuth angle F of side AB AB as well as the horizontal direction values FX AC′ , FX AD′ , FX BC′ , FX BD′ , according to the azimuth calculation principle, obtain the azimuth angles F AC′ , F AD′ , F BC′ , F BD′ ; S6. The distances L of the sides AC′, AD′, BC′, and BD′ calculated in S4 AC′ , L AD′ , L BC′ , L BD′ and the azimuth angles F of the sides AC′, AD′, BC′, and BD′ calculated in S5 AC′ , F AD′ , F BC′ , F BD′ and the plane coordinates of the known point A and the known point B, calculate the plane coordinates of the target point C and the target point D according to the forward calculation of coordinates; S7, the zenith angles ∠TAC, ∠TAD, ∠TBC, ∠TBD of the highest objects C and D at the position of the observation tower pole in S3, and the distances L of the sides AC′, AD′, BC′, BD′ calculated in S4, AC′ , L AD′ , L BC′ , L BD′ and the elevations of the known point A and the known point B, calculate the elevation H of the target point C according to the trigonometric function relationship C and the elevation H of the target point D D ; S8. Adjust the plane coordinates and elevations of target point C and target point D calculated in S6 and S7 to obtain the three-dimensional coordinates of target point C and target point D; S9. Calculate the length L of CD by the spatial distance formula CD .

2. The optimal calculation method for the line length between large-span towers in difficult areas according to claim 1, wherein In S1, when selecting two points, namely point A and point B, within a certain range outside the area of the tower pole line length to be calculated, during coordinate assumption and field selection, it is necessary to ensure that point A and point B can see each other. At the same time, it is also necessary to ensure that target point C and target point D can be clearly seen when setting up the instrument at point A, and target point C and target point D can also be clearly seen when setting up the instrument at point B.

3. The optimal calculation method for the line length between large-span towers in difficult areas according to claim 1, characterized in that, In S3, according to the observed horizontal direction values FX of the target points C and D AC′ , FX AD′ , FX BC′ , FX BD′ , the interior angles in △BAC′ and △ABD′ are obtained: ∠BAC′, ∠BAD′, ∠ABC′, ∠ABD′; According to the theorem of the sum of interior angles of a triangle being 180°, calculate the angles corresponding to side AB: ∠AC′B, ∠AD′B. The calculation formulas are as follows: ∠AC′B = 180° - (∠BAC′ + ∠ABC′) ∠AD′B = 180° - (∠BAD′ + ∠ABD′).

4. The optimal calculation method for the line length between large-span tower poles in difficult areas according to claim 1, characterized in that, In the step S4, calculate the distances \(L\) of the sides \(AC'\), \(AD'\), \(BC'\), and \(BD'\) according to the sine theorem AC′ , \(L\) AD′ , \(L\) BC′ , \(L\) BD′ , and the calculation formula is: where L AB is the distance to side AB; ∠AC′B is the angle corresponding to side AB; ∠ABC′ is the angle corresponding to side AC′; Similarly, the distances L of sides AD′, BC′, and BD′ are obtained. AD′ , L BC′ , L BD′ .

5. The optimal calculation method for the line length between large-span tower poles in difficult areas according to claim 1, characterized in that, In the step S5, the azimuth angles F of the sides AC′, AD′, BC′, and BD′ are obtained according to the azimuth angle calculation principle. AC′ , F AD′ , F BC′ , F BD′ , and the calculation formula is: F AC′ =F BA -∠BAC′ + 180° F AD′ =F BA -∠BAD′ + 180° F BC′ = F AB - ∠ABC′ - 180° F BD′ = F AB - ∠ABD′ - 180° Among them, F AB is the azimuth of side AB; F BA is the azimuth of side BA; ∠BAC′, ∠BAD′, ∠ABC′, and ∠ABD′ are turning angles.

6. The optimal calculation method for the line length between large-span tower poles in difficult areas according to claim 1, characterized in that In S6, calculate the plane coordinates of target point C according to the forward calculation of coordinates. The calculation formula is as follows: Among them, X A is the X-axis coordinate of point A; Y A is the Y-axis coordinate of point A; F AC′ is the azimuth of side AC′; L AC′ is the distance of side AC′; Similarly, the planar coordinates (X D , Y D ) of the target point D are obtained.

7. The optimal calculation method for the line length between large-span towers in difficult areas according to claim 1, characterized in that, In S7, calculate the elevation of target point C according to the trigonometric function relationship. The calculation formula is as follows: Among them, H A is the elevation of point A; L AC′ is the distance of side AC'; ∠TAC is the zenith angle observed at the target point C when the total station is set up at point A; Similarly, the elevation H of the target point D is obtained D .

8. The optimal calculation method for the line length between large-span towers in difficult areas according to claim 1, wherein In S8, the planar coordinates and elevations of the target points C and D calculated in S6 and S7 are adjusted, and finally the target point C(X C , Y C , H C ) and the target point D(X D , Y D , H D ) are obtained.

9. The optimal calculation method for the line length between large-span tower poles in difficult areas according to claim 1, characterized in that, In the above S9, the length L of CD is calculated by the spatial distance formula CD , and the calculation formula is: Among them, X C is the X-axis coordinate of the target point C; X D is the X-axis coordinate of the target point D; Y C is the Y-axis coordinate of the target point C; Y D is the Y-axis coordinate of the target point D; H C is the elevation of the target point C; H D is the elevation of the target point D.

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