A method for detecting encoder zero value error using non-main camera of photoelectric theodolite with multiple sensors

Abstract

The present invention relates to a method for detecting the zero-value error of an encoder of a photoelectric theodolite using a multi-sensor non-main camera, so as to solve the technical problem that the current photoelectric theodolite zero-value error correction method cannot be applied to correct the zero-value error of a multi-sensor theodolite using a non-main camera optical system, and belongs to the technical field of photoelectric theodolites. The method comprises the following steps: establishing a non-main camera imaging coordinate system, calculating the coordinates of the non-main camera center point position in the main camera imaging coordinate system; photographing an image of an azimuth mark in a positive mirror state, and recording the readings of a horizontal encoder and a pitch encoder; photographing an image of an azimuth mark in a reverse mirror state of a multi-sensor photoelectric theodolite, and recording the readings of a horizontal encoder and a pitch encoder in the reverse mirror state. The method of the present invention uses a non-main camera optical measurement system of a multi-sensor photoelectric theodolite to photograph the positive and reverse mirror images of a target range azimuth mark, correct the zero-value error of the encoder of the multi-sensor photoelectric theodolite, and can calculate the non-parallelism error at the same time.

Description

Technical Field

[0001] The invention relates to the technical field of photoelectric theodolites, and in particular to a method for detecting encoder zero-value errors of a photoelectric theodolite using a multi-sensor non-main camera. Background Art

[0002] Photoelectric theodolite is widely used in the measurement of the outer ballistic trajectory parameters of flying targets such as rockets, missiles and aerial bombs. It can also measure the target attitude and miss distance parameters in the encounter phase and record them in real time. It is one of the main optical measurement equipment in the shooting range. The typical photoelectric theodolite tracking frame is a two-axis ground-based structure, such as Figure 7 As shown, it consists of a vertical axis and a horizontal axis. The main optical system is installed in the middle of the horizontal axis. Its optical axis serves as the aiming axis (collimation axis) of the tracking frame and is perpendicular to the horizontal axis.

[0003] Under the control of the servo system, the aiming axis of the photoelectric theodolite can rotate around the horizontal and vertical axes in both azimuth and elevation to point to the target. Figure 8 As shown, ideally, the target point (x i ,y i ,z i ) is located on the aiming axis, and the azimuth angle A and elevation angle E of the target relative to the photoelectric theodolite can be described by the horizontal axis angle encoder and elevation axis angle encoder of the photoelectric theodolite.

[0004] The eccentric error of the encoder of the photoelectric theodolite itself will affect the angular measurement accuracy of the photoelectric theodolite. The horizontal code disk and pitch angle code disk of the encoder of the photoelectric theodolite are installed on the vertical axis and horizontal axis of the photoelectric theodolite. The installation and adjustment errors caused by the encoder after installation and the inconsistency with the optical axis become the zero value error of the encoder.

[0005] The zero-value error of the horizontal encoder refers to the angle value of the zero value of the equipment's horizontal code disk that deviates from the geodetic north or astronomical north. When the longitude and latitude are rotated so that the sighting axis is aligned with the direction of the orientation line (usually geodetic north), the angle difference g between it and that direction can be read from the horizontal encoder. In actual measurement, the zero-value error of the horizontal encoder can be solved based on the geodetic mark. An azimuth mark is set up near the photoelectric theodolite. Assuming that the true azimuth angle of the azimuth mark relative to the photoelectric theodolite site is α0, the main optical system of the photoelectric theodolite is aimed at the target. At this time, the reading of the horizontal code disk is the measurement value A of the photoelectric theodolite for the azimuth mark. f , then g=A f -α0.

[0006] The zero-value error of the pitch encoder refers to the angle value of the zero position of the equipment pitch code disc deviating from the horizontal direction. When the photoelectric theodolite is in the positive mirror state and the sighting axis points to the horizontal direction, the angle value read by the pitch encoder at this time is the zero-value error of the pitch encoder in the positive mirror state, which is also the angle between the horizontal plane and the zero-position scale of the pitch code disc, that is, h = EE f , where E is the horizontal direction of the sighting axis of the photoelectric theodolite when the mirror is positive, and E f It is the theoretical elevation value of the azimuth mark relative to the photoelectric theodolite.

[0007] At present, in order to improve the target detection capability, in addition to the main optical system, the photoelectric theodolite is additionally equipped with multiple sensors such as infrared, visible light, laser, radar, GPS, etc., forming a multi-sensor photoelectric theodolite. Generally, the main camera optical system is placed in the center of the horizontal axis of the multi-sensor photoelectric theodolite, while other non-main camera optical systems need to be fixed on the axis or axis head of the horizontal axis. The sighting axes of these non-main camera systems are difficult to be completely parallel to the main optical axis, so there is a non-parallelism error, which makes the current zero-value error calculation method of the encoder of the photoelectric theodolite unable to be applied to correct the zero-value error of the multi-sensor theodolite using the non-main camera optical system. Therefore, it is necessary to establish a general encoder zero-value error calculation method. At the same time, even for the main camera system, its projection center is often difficult to completely coincide with the rotation center of the multi-sensor photoelectric theodolite. Therefore, during the rotation of the multi-sensor photoelectric theodolite, the position of the projection center changes dynamically. The influence of this movement on the accuracy of the optical imaging system cannot be ignored in high-precision measurement.

[0008] The commonly used correction methods for the axis error, encoder error and other errors of the photoelectric theodolite are generally aimed at the main camera measurement system with the imaging optical axis located at the center of rotation. However, due to the non-main camera optical measurement system of the multi-sensor photoelectric theodolite, the non-main camera error must be detected and corrected first before the axis error and system error of the multi-sensor photoelectric theodolite can be corrected using the non-main camera measurement system.

[0009] Chinese patent document CN115683157A discloses a method for calibrating the optical axis parallelism of a multi-sensor photoelectric theodolite, in which visible markers and infrared markers are required, the center geodetic height of the marker pattern needs to be the same as the three-axis center position of the photoelectric theodolite, and the two markers are at a certain angle to the three-axis center of the photoelectric theodolite, and the angle between the infrared and visible light sensors needs to be known in advance. This method has strict restrictions on the shape, layout angle and height of the markers, and is difficult to adapt to the needs of the shooting range in the field environment.

[0010] Chinese patent document CN115388913A proposes a method for correcting relative errors in angle measurement of a multi-sensor system. However, the method is not related to the field of optical measurement of photoelectric theodolites, but is aimed at error correction of multi-sensors on board fixed ships.

[0011] Chinese patent document CN103727961A proposes a method for correcting dynamic errors of a photoelectric theodolite. Although this method uses positive and negative mirror data, the main errors corrected are those caused by the asynchrony between the encoder sampling time, exposure time and the miss distance.

[0012] Chinese patent document CN115406408A proposes a method for detecting and correcting the vertical axis tilt error of a photoelectric theodolite. Although the method corrects the axis system error of the photoelectric theodolite, it does not take into account the influence of the parallelism error of the non-primary optical system.

[0013] The paper "Dynamic Correction of Miss-Amount of Light-Spot Multi-Sensor Photoelectric Theodolite Using Coordinate Transformation" proposes a method of improving the miss-amount calculation method using coordinate transformation. This method takes into account the impact of the non-parallelism between the optical axis of the non-main camera system and the aiming axis of the photoelectric theodolite on the miss-amount calculation, but does not involve the specific method of measuring the non-parallelism in a shooting range environment.

[0014] The paper "Axis Parallelism Detection of Photoelectric Theodolite Suitable for Shooting Range" proposes a method for detecting the non-parallelism between the optical axis of the imaging system and the ideal aiming axis by using the images of the compass mark's positive and negative mirrors. Only the non-parallelism error is taken into account. However, the horizontal encoder and pitch encoder of a general photoelectric theodolite have zero-value errors. If the zero-value error is not corrected, a large error will occur in the encoder value read when the compass mark image is captured by the positive and negative mirrors, resulting in inaccurate calculated non-parallelism error. Therefore, the influence of the encoder zero-value error should be considered when detecting the non-parallelism error.

[0015] The paper "Research on Three-Difference Detection Method of T-Frame Photoelectric Theodolite in Shooting Range" mentions a three-difference detection method for T-type photoelectric theodolite, but it only targets ideal conditions, that is, the strict conditions that the non-main camera system is installed at one end of the horizontal axis and the optical axis is parallel to the main camera system's aiming axis. It does not consider the situation where the photoelectric theodolite with multiple sensors has non-parallelism errors. In actual situations, the photoelectric theodolite with multiple sensors cannot be arranged at only one end of the horizontal axis and non-parallelism errors will also exist. Summary of the invention

[0016] The present invention aims to solve the technical problem that the axis system error and system error of a multi-sensor photoelectric theodolite in the prior art cannot be correctly corrected, and provides a method for detecting the zero value error of an encoder by non-main camera of a multi-sensor photoelectric theodolite.

[0017] In order to solve the above technical problems, the technical solutions of the present invention are as follows:

[0018] A method for detecting encoder zero-value error by non-main camera using a multi-sensor photoelectric theodolite, wherein the method is applicable to measuring equipment including: a multi-sensor photoelectric theodolite, a compass, a high-precision geodetic coordinate measuring device, and image interpretation software;

[0019] The compass mark is a plane target with a characteristic point that is easy to identify. It is placed on the ground somewhere within the visual range of the multi-sensor photoelectric theodolite, and can be clearly imaged within the visual field of each optical sensor of the multi-sensor photoelectric theodolite.

[0020] A multi-sensor electro-optical theodolite is used to capture images of the compass;

[0021] High-precision geodetic coordinate measuring equipment is used to measure the geodetic coordinates of the compass mark and the rotation center of the multi-sensor photoelectric theodolite;

[0022] The image interpretation software is used to interpret the miss-of-target amount of the feature points of the compass in the compass image and calculate the angle of the feature points of the compass relative to the imaging center;

[0023] The method comprises the following steps:

[0024] Step S1: Place a high-precision geodetic coordinate measuring device at the location of the compass feature point, and measure the geodetic coordinates of the compass feature point as (L M B M H M );

[0025] Step S2: measuring the geodetic coordinates of the intersection of the three axes of the multi-sensor photoelectric theodolite, calculating the coordinates of the geodetic coordinates in the geocentric space rectangular coordinate system, and establishing a measurement coordinate system and a main camera imaging coordinate system at the intersection of the three axes;

[0026] Step S3: using the geodetic coordinates of the compass feature points measured in step S1, calculating the coordinates in the geocentric space rectangular coordinate system;

[0027] Step S4: establishing a non-main imaging coordinate system at the projection center of the non-main imaging system, and calculating the coordinates of the non-main imaging projection center point in the main imaging coordinate system;

[0028] Step S5: photographing an image of the azimuth mark in the normal mirror state of the multi-sensor photoelectric theodolite, and recording the readings of the horizontal encoder and the pitch encoder in the normal mirror state;

[0029] Step S6: photographing an image of a compass mark in a reverse mirror state of the multi-sensor photoelectric theodolite, and recording the readings of a horizontal encoder and a pitch encoder in the reverse mirror state;

[0030] Step S7: using image interpretation software to interpret the miss amount of the feature point of the compass in the positive mirror and the reverse mirror images, and calculating the angle of the feature point of the compass relative to the imaging center;

[0031] Step S8: Calculate the distance between the non-main-photographed projection center and the azimuth feature point when shooting the front mirror and the reverse mirror images;

[0032] Step S9: Calculate the comprehensive angle value of the azimuth mark feature point relative to the origin of the multi-sensor photoelectric theodolite measurement coordinate system when the front mirror and the reverse mirror of the multi-sensor photoelectric theodolite are taken, substitute it into the zero value error calculation formula, calculate the zero value error of the horizontal encoder and the pitch encoder of the multi-sensor photoelectric theodolite; and calculate the non-parallelism of the non-primary camera at the same time.

[0033] In the above technical solution, step S2 includes the following steps:

[0034] Step S21: The multi-sensor photoelectric theodolite is placed on a horizontal ground and leveled. A high-precision geodetic coordinate measuring device is placed directly below the intersection of the vertical axis, the horizontal axis and the sighting axis. The geodetic coordinates of the point are accurately measured. The elevation is added to the instrument height of the device to obtain the accurate geodetic coordinates of the intersection of the three axes, i.e., the origin of the measurement coordinate system, which is (L C B C H C );

[0035] Step S22: Calculate the azimuth feature point M when shooting the azimuth feature point M with the front mirror and the back mirror according to the following formula: C The geodetic coordinates are converted into the coordinates of the azimuth feature points in the geocentric rectangular coordinate system and the coordinates of the origin of the measurement coordinate system

[0036]

[0037] in, N is the radius of the ellipsoid, e is the first eccentricity of the earth, L is the geodetic longitude, B is the geodetic latitude, h is the geodetic height, and a is the major semi-axis of the reference ellipsoid;

[0038] Step S23: Establishing the main imaging coordinate system O with the intersection of the three axes of the multi-sensor photoelectric theodolite as the origin L X L Y L Z L , where X L The Y axis coincides with the sighting axis of the main optical sensor. When the sighting axis of the multi-sensor photoelectric theodolite is parallel to the horizontal plane and points to due north, L The axis coincides with the vertical axis of the multi-sensor photoelectric theodolite, and the upward direction is positive. LThe axis coincides with the horizontal axis of the multi-sensor photoelectric theodolite and is positive to the right.

[0039] In the above technical solution, step S3 includes the following steps:

[0040] Step S31: Convert the geodetic coordinates of the azimuth feature point into coordinates in the geocentric rectangular coordinate system according to the formula in step S2

[0041] Step S32: Calculate the coordinates of the compass feature point in the measurement coordinate system according to the following formula:

[0042]

[0043] Among them, L is the geodetic longitude; B is the geodetic latitude; is the coordinate of the azimuth feature point M in the geocentric rectangular coordinate system, To measure the coordinates of the origin of the coordinate system in the geocentric rectangular coordinate system, R x , R y , R z They are the coordinate transformation rotation matrices for rotating around the X-axis, Y-axis, and Z-axis respectively.

[0044] In the above technical solution, step S4 includes the following steps:

[0045] Step S41: The non-main camera projection center point O is measured by the multi-sensor photoelectric theodolite during the equipment installation process. F The relative position to the projection center of the main camera is at the non-main camera projection center point O F Establish the non-primary imaging coordinate system O F X F Y F Z F ;

[0046] Step S42: When the multi-sensor photoelectric theodolite is installed and adjusted, the non-main camera projection center point O is obtained by measuring the position relationship of the structure. F The coordinates in the main imaging coordinate system are (x FO ,y FO ,z FO ).

[0047] In the above technical solution, step S5 includes the following steps:

[0048] Step S51: Turn the multi-sensor photoelectric theodolite to a positive mirror state and align it with the azimuth mark;

[0049] Step S52: Use the non-main camera of the multi-sensor photoelectric theodolite to capture the image of the azimuth mark positive mirror, and record the horizontal encoder reading in the positive mirror state and pitch encoder readings

[0050] In the above technical solution, step S6 includes the following steps:

[0051] Step S61: Turn the multi-sensor photoelectric theodolite to the inverted mirror state and align it with the azimuth mark;

[0052] Step S62: Use the multi-sensor photoelectric theodolite to take a non-main camera to shoot the inverted image of the azimuth mark, and record the horizontal encoder reading in the inverted state and pitch encoder readings

[0053] In the above technical solution, step S7 includes the following steps:

[0054] Step S71: The image interpretation software imports the positive mirror image of the multi-sensor photoelectric theodolite and interprets the miss distance of the azimuth feature point M in the positive mirror image as (Δx z ,Δy z );

[0055] Step S72: The image interpretation software imports the multi-sensor photoelectric theodolite inverted mirror image and interprets the miss distance of the azimuth feature point M in the inverted mirror image as (Δx d ,Δy d );

[0056] Step S73: Calculate the angles of the azimuth feature points relative to the imaging center when the mirror is facing forward and the mirror is backward according to the following formulas: and

[0057]

[0058] Wherein, Angle represents the azimuth and elevation imaging angle of the target point relative to the imaging center, p is the non-primary pixel size of the multi-sensor photoelectric theodolite, f is the non-primary focal length of the multi-sensor photoelectric theodolite, and Δd is the miss distance.

[0059] In the above technical solution, step S8 includes the following steps:

[0060] Step S81: The non-main camera projection center is expressed as (x FO ,y FO ,z FO );

[0061] Step S82: According to the encoder values ​​recorded when shooting the azimuth mark positive mirror and reverse mirror, the coordinates of the non-main camera projection center point in the measurement coordinate system when shooting the positive mirror and reverse mirror are obtained using the following formula: and

[0062]

[0063] in, is the coordinate in the measured coordinate system, (A0, E0) is the horizontal encoder and pitch encoder reading of the multi-sensor photoelectric theodolite, R y , R z They are the coordinate transformation rotation matrices for rotation around the Y axis and around the Z axis respectively;

[0064] Step S83: Calculate the distance L between the compass feature point M and the non-main projection center point in the positive and negative mirrors according to the following formula: Z and L d :

[0065]

[0066] Among them, L is the distance in three-dimensional space between the center point of the non-main projection and the azimuth feature point, is the coordinate of the compass feature point in the measurement coordinate system.

[0067] In the above technical solution, step S9 includes the following steps:

[0068] Step S91: By taking into account the distance between the azimuth mark and the non-main projection center of the multi-sensor photoelectric theodolite when the front mirror and the back mirror are used to shoot the azimuth mark, the comprehensive angle value (A) of the multi-sensor photoelectric theodolite when the front mirror and the back mirror are used to shoot the azimuth mark is calculated according to the following formula: z ,E z ) and (A d ,E d ), and at the same time calculate the non-main camera's non-parallelism error (ΔA0, ΔE0):

[0069]

[0070] Among them, e is the first eccentricity of the earth, K z 、V z 、N z , K d 、V d 、N d , P are meaningless intermediate variables, L z , L d are the distances from the feature points of the azimuth mark to the center of the non-main camera projection when the mirror is facing forward or backward, are the pitch angle and azimuth angle of the azimuth feature point relative to the imaging center of the non-primary camera when the mirror is positive, are the pitch angle and azimuth angle of the azimuth feature point relative to the imaging center of the non-primary camera when the mirror is reversed, y FO 、z FOare the y and z coordinates of the center point of the non-main camera projection in the main camera imaging coordinate system, Δx z , Δy z are the miss distances obtained by reading the image of the compass positive mirror, Δx d , Δy d are the miss distances obtained by reading the inverted mirror image of the azimuth marker, They are the pitch and azimuth encoder readings when the mirror is facing forward. They are respectively the pitch and azimuth encoder readings when the mirror is reversed;

[0071] Step S92: Calculate the zero value error G of the horizontal encoder and the zero value error H of the pitch encoder according to the following formula;

[0072]

[0073] in, is the coordinate of the compass feature point in the measurement coordinate system.

[0074] In the above technical scheme, in order to reduce the impact of random errors, the measurements of step S5 to step S9 are repeated multiple times, and the average value is calculated. The average value is used as the zero-value error of the horizontal encoder and the zero-value error of the pitch encoder of the multi-sensor photoelectric theodolite. The correction amount according to the measured value is opposite to the error sign, and the correction amount is obtained to correct the zero-value error of the horizontal encoder and the pitch encoder.

[0075] The present invention has the following beneficial effects:

[0076] The method for detecting the zero-value error of an encoder by using a non-main camera of a multi-sensor photoelectric theodolite of the present invention uses a non-main camera optical measurement system of the multi-sensor photoelectric theodolite to shoot the positive and negative mirror images of the azimuth mark of a shooting range, corrects the zero-value error of the encoder of the multi-sensor photoelectric theodolite, and can calculate the non-parallelism error at the same time. The method improves the efficiency of shooting marks and error correction of the multi-sensor photoelectric theodolite of the shooting range, and shortens the preparation time before the task. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0078] Figure 1 The present invention is a schematic diagram of the steps of a method for detecting encoder zero-value error using a multi-sensor photoelectric theodolite in a non-main camera manner.

[0079] Figure 2 This is a schematic diagram of the layout of the photoelectric theodolite and azimuth mark.

[0080] Figure 3 Schematic diagram of the measurement coordinate system, the main imaging coordinate system, and the non-main imaging coordinate system.

[0081] Figure 4 Schematic diagram of the relative position of the non-main camera projection center and the origin of the main camera imaging coordinate system.

[0082] Figure 5 Schematic diagram of the zero-value error of the horizontal encoder.

[0083] Figure 6 Schematic diagram of the zero-value error of the pitch encoder.

[0084] Figure 7 It is a three-axis schematic diagram of a multi-sensor photoelectric theodolite in the prior art.

[0085] Figure 8 It is a schematic diagram of the measurement principle of the photoelectric theodolite in the prior art. DETAILED DESCRIPTION

[0086] The inventive concept of the present invention is:

[0087] The method for detecting encoder zero-value error by non-main camera of a multi-sensor photoelectric theodolite of the present invention utilizes the non-main camera measurement system of the multi-sensor photoelectric theodolite to correct the axis system error and encoder error of the multi-sensor photoelectric theodolite.

[0088] The method for detecting the zero-value error of an encoder by non-primary photography of a multi-sensor photoelectric theodolite of the present invention utilizes the image of the compass mark positive and negative mirror captured by the non-primary photography measurement system, and considers the correction of the non-parallelism error in the process of calculating the encoder error, which innovatively makes it possible to correct the encoder error by non-primary photography measurement system of a multi-sensor photoelectric theodolite, and simplifies the error calculation process.

[0089] The present invention is described in detail below with reference to the accompanying drawings.

[0090] The method of the present invention for detecting encoder zero-value error by non-main camera using a multi-sensor photoelectric theodolite is implemented based on the following measuring equipment, including: a multi-sensor photoelectric theodolite, a compass, a high-precision geodetic coordinate measuring device, and image interpretation software.

[0091] As attached Figure 2 As shown, the compass mark is a plane target with a characteristic point that is easy to identify. It is placed on the ground somewhere within the visual range of the multi-sensor photoelectric theodolite. The compass mark can be clearly imaged within the field of view of each optical sensor of the multi-sensor photoelectric theodolite.

[0092] A multi-sensor electro-optical theodolite is used to capture images of the compass;

[0093] High-precision geodetic coordinate measuring equipment is used to measure the geodetic coordinates of the compass mark and the rotation center of the multi-sensor photoelectric theodolite;

[0094] The image interpretation software is used to interpret the miss-of-target amount of the feature points of the compass in the compass image and calculate the angle of the feature points of the compass relative to the imaging center;

[0095] As attached Figure 3 As shown, a measurement coordinate system, a main imaging coordinate system, and a non-main imaging coordinate system are established.

[0096] Measurement coordinate system O C X C Y C Z C The intersection of the three axes of the multi-sensor photoelectric theodolite is taken as the origin. C The positive direction of the Y axis points to the north of the earth. C The positive direction of the axis is perpendicular to the horizontal plane where the origin is and points to the sky. C Axis and X C Axis and Y C The axes form a right-handed coordinate system.

[0097] Main imaging coordinate system O L X L Y L Z L The intersection point O of the three axes of the multi-sensor photoelectric theodolite L is the origin, where X L The Y axis coincides with the sighting axis of the main optical sensor. When the sighting axis of the multi-sensor photoelectric theodolite is parallel to the horizontal plane and points to due north, L The axis coincides with the vertical axis of the multi-sensor photoelectric theodolite, and the upward direction is positive. L The axis coincides with the horizontal axis of the multi-sensor photoelectric theodolite and is positive to the right.

[0098] Non-primary imaging coordinate system O F X F Y F Z F The projection center of the non-main imaging system of the multi-sensor photoelectric theodolite is the non-main projection center point O F is the origin, X F The Y axis is the optical axis of the non-primary imaging system. F The axis is parallel to the image plane of the non-primary imaging system. When the mirror is positive, the positive direction points to the sky. F The axis is parallel to the image plane of the non-primary imaging system, and is positive to the right when the mirror is positive.

[0099] The method of the photoelectric theodolite using multiple sensors to detect the zero-value error of the encoder using non-main camera is as follows: Figure 1 As shown, the following steps are included:

[0100] Step S1: Place a high-precision geodetic coordinate measuring device at the position of the compass feature point M, and accurately measure the geodetic coordinates of the compass feature point M as (L MB M H M ).

[0101] Step S2: measuring the geodetic coordinates of the intersection of the three axes of the multi-sensor photoelectric theodolite, calculating the coordinates of the geodetic coordinates in the geocentric space rectangular coordinate system, and establishing a measurement coordinate system and a main camera imaging coordinate system at the intersection of the three axes, including the following steps:

[0102] Step S21: The multi-sensor photoelectric theodolite is placed on a horizontal ground and leveled. A high-precision geodetic coordinate measuring device is placed directly below the intersection of the vertical axis, the horizontal axis and the sighting axis. The geodetic coordinates of the point are accurately measured. The elevation is added to the instrument height of the device to obtain the accurate geodetic coordinates of the intersection of the three axes, i.e., the origin of the measurement coordinate system, which is (L C B C H C );

[0103] Step S22: Calculate the azimuth feature point M when shooting the azimuth feature point M with the front mirror and the back mirror according to the following formula: C The geodetic coordinates are converted into the coordinates of the azimuth feature points in the geocentric rectangular coordinate system and the coordinates of the origin of the measurement coordinate system

[0104]

[0105] in, N is the radius of the ellipsoid, e is the first eccentricity of the earth, L is the geodetic longitude, B is the geodetic latitude, h is the geodetic height, and a is the major semi-axis of the reference ellipsoid;

[0106] Step S23: Establishing the main imaging coordinate system O with the intersection of the three axes of the multi-sensor photoelectric theodolite as the origin L X L Y L Z L , where X L The Y axis coincides with the sighting axis of the main optical sensor. When the sighting axis of the multi-sensor photoelectric theodolite is parallel to the horizontal plane and points to due north, L The axis coincides with the vertical axis of the multi-sensor photoelectric theodolite, and the upward direction is positive. L The axis coincides with the horizontal axis of the multi-sensor photoelectric theodolite and is positive to the right.

[0107] Step S3: using the geodetic coordinates of the compass feature point M measured in step S1, calculating the coordinates in the geocentric space rectangular coordinate system, including the following steps:

[0108] Step S31: Convert the geodetic coordinates of the compass feature point M into coordinates in the geocentric rectangular coordinate system according to the formula in step S2:

[0109] Step S32: Calculate the coordinates of the compass feature point M in the measurement coordinate system according to the following formula:

[0110]

[0111] Among them, L is the geodetic longitude; B is the geodetic latitude; is the coordinate of the azimuth feature point M in the geocentric rectangular coordinate system, To measure the coordinates of the origin of the coordinate system in the geocentric rectangular coordinate system, R x , R y , R z They are the coordinate transformation rotation matrices for rotating around the X-axis, Y-axis, and Z-axis respectively.

[0112] Step S4: establishing a non-main camera imaging coordinate system at the projection center of the non-main camera imaging system, and calculating the coordinates of the non-main camera projection center point in the main camera imaging coordinate system, including the following steps:

[0113] Step S41: The non-main camera projection center point O is measured by the multi-sensor photoelectric theodolite during the equipment installation process. F The relative position to the projection center of the main camera is at the non-main camera projection center point O F Establish the non-primary imaging coordinate system O F X F Y F Z F ;

[0114] Step S42: As shown in the attached Figure 3 When the multi-sensor photoelectric theodolite is installed and adjusted, the non-main camera projection center point O is obtained by measuring the position relationship of the structure. F The coordinates in the main imaging coordinate system are (x FO ,y FO ,z FO ).

[0115] Step S5: photographing the azimuth mark image in the positive mirror state of the multi-sensor photoelectric theodolite, and recording the readings of the horizontal encoder and the pitch encoder in the positive mirror state; comprising the following steps:

[0116] Step S51: Turn the multi-sensor photoelectric theodolite to a positive mirror state and align it with the azimuth mark;

[0117] Step S52: Use the non-main camera of the multi-sensor photoelectric theodolite to capture the image of the azimuth mark positive mirror, and record the horizontal encoder reading in the positive mirror state and pitch encoder readings

[0118] Step S6: photographing the azimuth mark image in the inverted mirror state of the multi-sensor photoelectric theodolite, and recording the readings of the horizontal encoder and the pitch encoder in the inverted mirror state, including the following steps:

[0119] Step S61: Turn the multi-sensor photoelectric theodolite to the inverted mirror state and align it with the azimuth mark;

[0120] Step S62: Use the multi-sensor photoelectric theodolite to take a non-main camera to shoot the inverted image of the azimuth mark, and record the horizontal encoder reading in the inverted state and pitch encoder readings

[0121] Step S7: using image interpretation software to interpret the miss amount of the compass feature point M in the compass positive mirror and inverted mirror images, and calculating the angle of the compass feature point M relative to the imaging center; comprising the following steps:

[0122] Step S71: The image interpretation software imports the positive mirror image of the multi-sensor photoelectric theodolite and interprets the miss distance of the azimuth feature point M in the positive mirror image as (Δx z ,Δy z );

[0123] Step S72: The image interpretation software imports the multi-sensor photoelectric theodolite inverted mirror image and interprets the miss distance of the azimuth feature point M in the inverted mirror image as (Δx d ,Δy d );

[0124] Step S73: Calculate the angles of the azimuth feature points relative to the imaging center when the mirror is facing forward and the mirror is backward according to the following formulas: and

[0125]

[0126] Wherein, Angle represents the azimuth and elevation imaging angle of the target point relative to the imaging center, p is the non-primary pixel size of the multi-sensor photoelectric theodolite, f is the non-primary focal length of the multi-sensor photoelectric theodolite, and Δd is the miss distance.

[0127] Step S8: Calculating the distance between the non-main-photograph projection center and the azimuth feature point when photographing the front mirror and the reverse mirror images, including the following steps:

[0128] Step S81: Figure 4 The figure shows the relative relationship between the non-main camera projection center and the origin of the measurement coordinate system. The multi-sensor photoelectric theodolite can measure the distance between the non-main camera projection center and the origin of the main camera imaging coordinate system during installation. The non-main camera projection center can be expressed in the main camera imaging coordinate system as (xFO ,y FO ,z FO ).

[0129] Step S82: The main imaging coordinate system can be regarded as the measurement coordinate system obtained by rotating horizontally around the y-axis and rotating in the pitch direction around the z-axis. Then, according to the encoder values ​​recorded when shooting the azimuth mark positive mirror and reverse mirror, the coordinates of the non-main imaging projection center point in the measurement coordinate system when the positive mirror and reverse mirror are obtained by the following formula: and

[0130]

[0131] in, is the coordinate in the measured coordinate system, (A0, E0) is the horizontal encoder and pitch encoder reading of the multi-sensor photoelectric theodolite, R y , R z They are the coordinate transformation rotation matrices for rotation around the Y axis and around the Z axis respectively;

[0132] Step S83: Calculate the distance L between the compass feature point M and the non-main projection center point in the positive and negative mirrors according to the following formula: Z and L d :

[0133]

[0134] Among them, L is the distance in three-dimensional space between the center point of the non-main projection and the azimuth feature point, is the coordinate of the compass feature point in the measurement coordinate system.

[0135] Step S9: Calculate the comprehensive angle value of the azimuth feature point relative to the origin of the multi-sensor photoelectric theodolite measurement coordinate system when the multi-sensor photoelectric theodolite is photographed by the positive mirror and the reverse mirror, and bring it into the zero-value error calculation formula to calculate the zero-value error of the horizontal encoder and the pitch encoder of the multi-sensor photoelectric theodolite. At the same time, the non-parallelism of the non-primary camera can be calculated; including the following steps:

[0136] Step S91: By taking into account the distance between the azimuth mark and the non-main projection center of the multi-sensor photoelectric theodolite when the front mirror and the back mirror are used to shoot the azimuth mark, the comprehensive angle value (A) of the multi-sensor photoelectric theodolite when the front mirror and the back mirror are used to shoot the azimuth mark is calculated according to the following formula: z ,E z ) and (A d ,E d ), and the non-main camera non-parallelism error (ΔA0, ΔE0) can be calculated at the same time:

[0137]

[0138] Among them, e is the first eccentricity of the earth, K z 、V z 、N z , K d 、V d 、N d , P are meaningless intermediate variables, L z , L d are the distances from the feature points of the azimuth mark to the center of the non-main camera projection when the mirror is facing forward or backward, are the pitch angle and azimuth angle of the azimuth feature point relative to the imaging center of the non-primary camera when the mirror is positive, are the pitch angle and azimuth angle of the azimuth feature point relative to the imaging center of the non-primary camera when the mirror is reversed, y FO 、z FO are the y and z coordinates of the center point of the non-main camera projection in the main camera imaging coordinate system, Δx z , Δy z are the miss distances obtained by reading the image of the compass positive mirror, Δx d , Δy d are the miss distances obtained by reading the inverted mirror image of the azimuth marker, They are the pitch and azimuth encoder readings when the mirror is facing forward. They are respectively the pitch and azimuth encoder readings when the mirror is reversed;

[0139] Step S92: Figure 5 and Figure 6 The figure shows the zero-value error diagram of the encoder of the multi-sensor photoelectric theodolite. When calculating the zero-value error of the horizontal encoder, it is necessary to compare it with the true value of the azimuth. Therefore, it is necessary to bring in and determine the coordinates of the azimuth feature point in the measurement coordinate system. According to the following formula, the zero-value error G of the horizontal encoder and the zero-value error H of the pitch encoder are calculated.

[0140]

[0141] in, is the coordinate of the compass feature point in the measurement coordinate system.

[0142] In order to reduce the impact of random errors, the measurements of step S5 to step S9 are repeated multiple times, and the average value is calculated. The average value is used as the zero-value error of the horizontal encoder and the zero-value error of the pitch encoder of the multi-sensor photoelectric theodolite. The correction amount can be obtained based on the fact that the correction amount of the measured value is opposite to the sign of the error, which is used to correct the zero-value error of the horizontal encoder and the pitch encoder.

[0143] The method for detecting the zero-value error of an encoder by using a non-main camera of a multi-sensor photoelectric theodolite of the present invention uses a non-main camera optical measurement system of the multi-sensor photoelectric theodolite to shoot the positive and negative mirror images of the azimuth mark of a shooting range, corrects the zero-value error of the encoder of the multi-sensor photoelectric theodolite, and can calculate the non-parallelism error at the same time. The method improves the efficiency of shooting marks and error correction of the multi-sensor photoelectric theodolite of the shooting range, and shortens the preparation time before the task.

[0144] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for detecting encoder zero value error by non-main camera using a multi-sensor photoelectric theodolite, characterized in that: The measuring equipment applicable to this method includes: multi-sensor photoelectric theodolite, azimuth mark, high-precision geodetic coordinate measuring equipment, image interpretation software; The compass mark is a plane target with a characteristic point that is easy to identify. It is placed on the ground somewhere within the visual range of the multi-sensor photoelectric theodolite, and can be clearly imaged within the visual field of each optical sensor of the multi-sensor photoelectric theodolite. A multi-sensor electro-optical theodolite is used to capture images of the compass; High-precision geodetic coordinate measuring equipment is used to measure the geodetic coordinates of the compass mark and the rotation center of the multi-sensor photoelectric theodolite; The image interpretation software is used to interpret the miss-of-target amount of the feature points of the compass in the compass image and calculate the angle of the feature points of the compass relative to the imaging center; The method comprises the following steps: Step S1: placing a high-precision geodetic coordinate measuring device at the position of the compass feature point, and measuring the geodetic coordinates of the compass feature point as (LMBMHM); Step S2: measuring the geodetic coordinates of the intersection of the three axes of the multi-sensor photoelectric theodolite, calculating the coordinates of the geodetic coordinates in the geocentric space rectangular coordinate system, and establishing a measurement coordinate system and a main camera imaging coordinate system at the intersection of the three axes; Step S3: using the geodetic coordinates of the compass feature points measured in step S1, calculating the coordinates in the geocentric space rectangular coordinate system; Step S4: establishing a non-main imaging coordinate system at the projection center of the non-main imaging system, and calculating the coordinates of the non-main imaging projection center point in the main imaging coordinate system; Step S5: photographing an image of the azimuth mark in the normal mirror state of the multi-sensor photoelectric theodolite, and recording the readings of the horizontal encoder and the pitch encoder in the normal mirror state; Step S6: photographing an image of a compass mark in a reverse mirror state of the multi-sensor photoelectric theodolite, and recording the readings of a horizontal encoder and a pitch encoder in the reverse mirror state; Step S7: using image interpretation software to interpret the miss amount of the feature point of the compass in the positive mirror and the reverse mirror images, and calculating the angle of the feature point of the compass relative to the imaging center; Step S8: Calculate the distance between the non-main-photographed projection center and the azimuth feature point when shooting the front mirror and the reverse mirror images; Step S9: Calculate the comprehensive angle value of the azimuth mark feature point relative to the origin of the multi-sensor photoelectric theodolite measurement coordinate system when the front mirror and the reverse mirror of the multi-sensor photoelectric theodolite are taken, substitute it into the zero value error calculation formula, calculate the zero value error of the horizontal encoder and the pitch encoder of the multi-sensor photoelectric theodolite; and calculate the non-parallelism of the non-primary camera at the same time.

2. The method for detecting encoder zero-value error by non-main camera using a multi-sensor photoelectric theodolite according to claim 1, characterized in that: Step S2 includes the following steps: Step S21: The multi-sensor photoelectric theodolite is placed on a horizontal ground and leveled. A high-precision geodetic coordinate measuring device is placed directly below the intersection of the vertical axis, the horizontal axis and the sighting axis. The geodetic coordinates of the point are accurately measured. The elevation is added to the instrument height of the device to obtain the accurate geodetic coordinates of the intersection of the three axes, i.e., the origin of the measurement coordinate system, which is (L C B C H C ); Step S22: When the compass feature point M is photographed by the positive mirror and the reverse mirror, the geodetic coordinates of the compass feature point M and the origin OC of the multi-sensor photoelectric theodolite measurement coordinate system are converted into the coordinates of the compass feature point in the geocentric space rectangular coordinate system according to the following formula: and the coordinates of the origin of the measurement coordinate system in, N is the radius of the ellipsoid, e is the first eccentricity of the earth, L is the geodetic longitude, B is the geodetic latitude, h is the geodetic height, and a is the major semi-axis of the reference ellipsoid; Step S23: Establishing the main imaging coordinate system O with the intersection of the three axes of the multi-sensor photoelectric theodolite as the origin L X L Y L Z L , where X L The Y axis coincides with the sighting axis of the main optical sensor. When the sighting axis of the multi-sensor photoelectric theodolite is parallel to the horizontal plane and points to due north, L The axis coincides with the vertical axis of the multi-sensor photoelectric theodolite, and the upward direction is positive. L The axis coincides with the horizontal axis of the multi-sensor photoelectric theodolite and is positive to the right.

3. The method for detecting encoder zero-value error by non-main camera using a multi-sensor photoelectric theodolite according to claim 2, characterized in that: Step S3 includes the following steps: Step S31: Convert the geodetic coordinates of the azimuth feature point into coordinates in the geocentric rectangular coordinate system according to the formula in step S2 Step S32: Calculate the coordinates of the compass feature point in the measurement coordinate system according to the following formula: Among them, L is the geodetic longitude; B is the geodetic latitude; is the coordinate of the azimuth feature point M in the geocentric rectangular coordinate system, To measure the coordinates of the origin of the coordinate system in the geocentric rectangular coordinate system, R x , R y , R z They are the coordinate transformation rotation matrices for rotating around the X-axis, Y-axis, and Z-axis respectively.

4. The method for detecting encoder zero-value error by non-main camera using a multi-sensor photoelectric theodolite according to claim 1, characterized in that: Step S4 includes the following steps: Step S41: The non-main camera projection center point O is measured by the multi-sensor photoelectric theodolite during the equipment installation process. F The relative position with the projection center of the main camera, establish the non-main camera imaging coordinate system O at the non-main camera projection center point OF F X F Y F Z F ; Step S42: When the multi-sensor photoelectric theodolite is installed and adjusted, the coordinates of the non-main camera projection center point OF in the main camera imaging coordinate system are obtained by measuring the positional relationship of the structure: (x FO ,y FO ,z FO ).

5. The method for detecting encoder zero-value error by non-main camera using a multi-sensor photoelectric theodolite according to claim 1, characterized in that: Step S5 includes the following steps: Step S51: Turn the multi-sensor photoelectric theodolite to a positive mirror state and align it with the azimuth mark; Step S52: Use the non-main camera of the multi-sensor photoelectric theodolite to capture the image of the azimuth mark positive mirror, and record the horizontal encoder reading in the positive mirror state and pitch encoder readings 6. The method for detecting encoder zero-value error by non-main camera using a multi-sensor photoelectric theodolite according to claim 1, characterized in that: Step S6 includes the following steps: Step S61: Turn the multi-sensor photoelectric theodolite to the inverted mirror state and align it with the azimuth mark; Step S62: Use the multi-sensor photoelectric theodolite to take a non-main camera to shoot the inverted image of the azimuth mark, and record the horizontal encoder reading in the inverted state and pitch encoder readings 7. The method for detecting encoder zero-value error by non-main camera using a multi-sensor photoelectric theodolite according to claim 1, characterized in that: Step S7 includes the following steps: Step S71: The image interpretation software imports the positive mirror image of the multi-sensor photoelectric theodolite and interprets the miss distance of the azimuth feature point M in the positive mirror image as (Δx z ,Δy z ); Step S72: The image interpretation software imports the multi-sensor photoelectric theodolite inverted mirror image and interprets the miss distance of the azimuth feature point M in the inverted mirror image as (Δx d ,Δy d ); Step S73: Calculate the angles of the azimuth feature points relative to the imaging center when the mirror is facing forward and the mirror is backward according to the following formulas: and Wherein, Angle represents the azimuth and elevation imaging angle of the target point relative to the imaging center, p is the non-primary pixel size of the multi-sensor photoelectric theodolite, f is the non-primary focal length of the multi-sensor photoelectric theodolite, and Δd is the miss distance.

8. The method for detecting encoder zero-value error by non-main camera using a multi-sensor photoelectric theodolite according to claim 1, characterized in that: Step S8 includes the following steps: Step S81: The non-main camera projection center is expressed as (x FO ,y FO ,z FO ); Step S82: According to the encoder values ​​recorded when shooting the azimuth mark positive mirror and reverse mirror, the coordinates of the non-main camera projection center point in the measurement coordinate system when shooting the positive mirror and reverse mirror are obtained using the following formula: and in, is the coordinate in the measured coordinate system, (A0, E0) is the horizontal encoder and pitch encoder reading of the multi-sensor photoelectric theodolite, R y , R z They are the coordinate transformation rotation matrices for rotation around the Y axis and around the Z axis respectively; Step S83: Calculate the distance L between the compass feature point M and the non-main projection center point in the positive and negative mirrors according to the following formula: Z and L d : Among them, L is the distance in three-dimensional space between the center point of the non-main projection and the azimuth feature point, is the coordinate of the compass feature point in the measurement coordinate system.

9. The method for detecting encoder zero-value error by non-main camera using a multi-sensor photoelectric theodolite according to claim 1, characterized in that: Step S9 includes the following steps: Step S91: By taking into account the distance between the azimuth mark and the non-main projection center of the multi-sensor photoelectric theodolite when the front mirror and the back mirror are used to shoot the azimuth mark, the comprehensive angle value (A) of the multi-sensor photoelectric theodolite when the front mirror and the back mirror are used to shoot the azimuth mark is calculated according to the following formula: z ,E z ) and (A d ,E d ), and at the same time calculate the non-main camera's non-parallelism error (ΔA0, ΔE0): Among them, e is the first eccentricity of the earth, K z 、V z 、N z , K d 、V d 、N d , P are meaningless intermediate variables, L z , L d are the distances from the feature points of the azimuth mark to the center of the non-main camera projection when the mirror is facing forward or backward, are the pitch angle and azimuth angle of the azimuth feature point relative to the imaging center of the non-primary camera when the mirror is positive, are the pitch angle and azimuth angle of the azimuth feature point relative to the imaging center of the non-primary camera when the mirror is reversed, y FO 、z FO are the y and z coordinates of the center point of the non-main camera projection in the main camera imaging coordinate system, Δx z , Δy z are the miss distances obtained by reading the image of the compass positive mirror, Δx d , Δy d are the miss distances obtained by reading the inverted mirror image of the azimuth mark, They are respectively the pitch and azimuth encoder readings when the mirror is positive, They are respectively the pitch and azimuth encoder readings when the mirror is reversed; Step S92: Calculate the zero-value error G of the horizontal encoder and the zero-value error H of the pitch encoder according to the following formula; in, is the coordinate of the compass feature point in the measurement coordinate system.

10. The method for detecting encoder zero-value error by non-main camera using a multi-sensor photoelectric theodolite according to any one of claims 1 to 9, characterized in that: In order to reduce the impact of random errors, the measurements of step S5 to step S9 are repeated multiple times, and the average value is calculated. The average value is used as the zero-value error of the horizontal encoder and the zero-value error of the pitch encoder of the multi-sensor photoelectric theodolite. The correction amount based on the correction amount of the measured value is opposite to the error sign, and the correction amount is obtained to correct the zero-value error of the horizontal encoder and the pitch encoder.

Images