A mobile measurement and control platform inertial navigation calibration device and method

Abstract

The present invention discloses an inertial navigation calibration device and method for a mobile measurement and control platform, and belongs to the field of measurement and control and radar technology. The basic principle is to construct a far-field calibration environment for a mobile measurement and control platform, determine the accurate orientation of the calibration antenna relative to the measurement and control antenna through high-precision position measurement, and obtain the direction of the antenna in the vehicle coordinate system through the measurement and control antenna capture and tracking, so as to correct the inertial navigation transfer matrix, so that the inertial navigation output attitude information is consistent with the vehicle attitude, and the output position information coincides with the centroid of the measurement and control antenna, and completes the high-precision calibration of the inertial navigation attitude and position. The present invention can complete the high-precision inertial navigation calibration of the vehicle-carrying mobile measurement and control platform with only one calibration antenna, and reduces the number of calibration reference targets and environmental requirements, can be executed around the clock, and has universal applicability.

Description

Technical Field

[0001] The invention relates to the fields of measurement and control and radar, and in particular to an inertial navigation calibration method for a mobile measurement and control platform. Background Art

[0002] In the field of mobile measurement and control, the mobile measurement and control system is required to have the ability of in-motion measurement and control. On the one hand, the antenna servo control and measurement and control equipment have the ability to isolate the rocking of the vehicle and the ship, and can achieve stable target tracking when the platform is maneuvering. On the other hand, it is necessary to have high-precision attitude and positioning capabilities to obtain the position and attitude of the vehicle in real time and correct the target pointing deviation caused by the maneuvering of the vehicle. The mobile measurement and control platform generally obtains the platform position and attitude information in real time through inertial navigation. After the inertial navigation is installed, the installation error is eliminated through calibration so that the position and attitude information output by the inertial navigation is consistent with the measurement and control antenna. The measurement and control technology for vehicle maneuvers is a new technology that has begun to develop in recent years. At present, there are few studies on the calibration methods of vehicle-mounted mobile platforms. The inertial navigation calibration method of the vehicle-mounted mobile platform can refer to the calibration method of the ship-mounted platform. The conventional solution is to use multi-star positioning to determine the transfer matrix between the inertial navigation coordinate system and the ship coordinate system, and to correct the inertial navigation output data. The main problems with this method are:

[0003] 1) Calibration is limited by time and weather. Since it needs to calibrate the star mark, it can generally only be done at night when the weather is clear;

[0004] 2) A large number of targets are required, generally more than 3 stars are needed to obtain an accurate transfer matrix;

[0005] 3) The calibration of star mark is affected by the atmospheric environment and is prone to large errors. Summary of the invention

[0006] In view of this, the present invention proposes a mobile measurement and control platform inertial navigation calibration device and method. The design can be used for inertial navigation calibration of a mobile measurement and control platform on a vehicle, and has low requirements for the calibration environment, can be performed all day, and only requires one calibration antenna to complete the reference target alignment and realize inertial navigation calibration.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A mobile measurement and control platform inertial navigation calibration device, comprising a carrier, a beacon, a leveling mechanism 4, a shelter 5, a measurement and control antenna 6, an inertial navigation 7, a low-light television 8, a measurement and control device and a calibration antenna 10, wherein the carrier comprises a tractor 1 and a semi-trailer 2;

[0009] A leveling mechanism 4 is installed around the chassis of the semi-trailer 2; a square cabin 5 is installed on the semi-trailer 2, including an equipment cabin 11 and an antenna cabin 12; a measurement and control antenna 6 is installed in the antenna cabin 12, and is fixedly connected to the chassis of the semi-trailer 2; an inertial navigation system 7 is installed on an inertial navigation installation platform on the side of the sleeve of the measurement and control antenna 6; a low-light television 8 is installed behind the measurement and control antenna 6, with the lens facing the direction of the antenna wave; the measurement and control equipment includes a measurement and control equipment cabinet 9 and an operating table 13, which are installed in the equipment cabin 11; a beacon machine and a calibration antenna 10 are located in the far field area outside the vehicle.

[0010] Furthermore, the vehicle chassis is firmly connected to the measurement and control antenna 6, and the azimuth rotation platform of the measurement and control antenna 6 is parallel to the vehicle chassis; the inertial navigation 7 is installed on the inertial navigation installation platform, the inertial navigation installation platform of the inertial navigation 7 is firmly connected to the measurement and control antenna 6, and when the measurement and control antenna 6 is erected, the inertial navigation installation platform of the inertial navigation 7 is parallel to the azimuth rotation platform of the measurement and control antenna 6.

[0011] Furthermore, the calibration antenna 10 is placed on a vehicle calibration pole, a calibration tower or other high ground; the calibration antenna 10 should meet the far-field condition, that is, the distance between the calibration antenna 10 and the measurement and control antenna 6 is greater than 2D. 2 / λ; When the calibration antenna 10 does not meet the far-field condition, the distance between the calibration antenna 10 and the measurement and control antenna 6 should not be less than D 2 / 2λ; where D is the diameter of the measurement and control antenna 6, and λ is the carrier wavelength of the calibration signal;

[0012] Furthermore, the position measurement of the measurement and control antenna 6 and the calibration antenna 10 adopts differential GPS, total station or other high-precision position measurement methods. The azimuth error caused by the positioning error should be lower than the inertial navigation heading accuracy, that is, the position error Wherein, L is the distance between the calibration antenna 10 and the measurement and control antenna 6 in the horizontal plane X of the navigation coordinate system. n O n Y n The projection distance, φ e is the inertial navigation accuracy in arc seconds.

[0013] A method for calibrating an inertial navigation system of a mobile measurement and control platform based on the above device comprises the following steps:

[0014] Step 1: Place the vehicle on a hard surface and keep it stationary. Adjust the leveling mechanism to make the vehicle chassis level, that is, the horizontal plane X of the vehicle coordinate system. b O b Y b Horizontal plane X with navigation coordinate system n O n Y n Parallel, so that the horizontal accuracy of the disk after adjustment is better than the preset accuracy

[0015] Step 2: Obtain the coordinates of the center of the telemetry antenna in the ENU coordinate system through geodetic measurement and calculation of the vehicle structure parameters [x n1 ,y n1 ,z n1 ]; Among them, the ENU coordinate system and the navigation coordinate system X n Y n Z n coincide;

[0016] Step 3: Use the image level to fine-tune the level of the disk to make the level accuracy of the disk meet the preset accuracy.

[0017] Step 4: Turn on the inertial navigation system for coarse alignment and fine alignment to obtain the attitude matrix of the inertial navigation coordinate system and the navigation coordinate system, namely, the inertial navigation heading angle φ, pitch angle θ and roll angle γ;

[0018] Step 5: Place the beacon and calibration antenna in the far field of the antenna, use a low-light television to align the measurement and control antenna with the direction of the far-field calibration antenna, and measure the coordinates of the calibration antenna center in the ENU coordinate system [x n2 ,y n2 ,z n2 ]; At the same time, the beacon transmits the calibration signal through the far-field calibration antenna;

[0019] Step 6: The measurement and control equipment is set to the capture and tracking mode. The measurement and control equipment controls the measurement and control antenna to capture and track. The measurement and control antenna captures the calibration signal and switches to the tracking mode. At this time, the center of the electrical axis of the measurement and control antenna is aligned with the calibration antenna. The value φ1 of the measurement and control antenna azimuth encoder is read out, that is, the angle between the measurement and control antenna pointing azimuth and the vehicle coordinate system azimuth 0°.

[0020] Step 7, correct the attitude matrix output by the inertial navigation system to make the inertial navigation coordinate system coincide with the vehicle coordinate system. Specifically, first, correct the pitch angle and roll angle output by the inertial navigation system to 0°, that is, θ = 0°, γ = 0°, and then correct the heading angle output by the inertial navigation system to φ2-φ1; where φ2 is the vector of the line connecting the phase center of the measurement and control antenna and the calibration antenna in the horizontal plane X of the navigation coordinate system. n O n Y n The angle between the projection and the navigation coordinate system azimuth 0°, η=atan2(y n2 -y n1 ,x n2 -x n1 )×180 / π;

[0021] Step 8, measure or calculate the three-dimensional coordinates of the phase center of the measurement and control antenna and the inertial navigation center, including longitude, latitude and altitude, and correct the inertial navigation position information so that the inertial navigation output position center coincides with the phase center of the measurement and control antenna.

[0022] Furthermore, the specific method of step 3 is:

[0023] Place an image level on the azimuth turntable platform of the measurement and control antenna, with the knob end of the image level facing the azimuth rotation center, fix the antenna elevation angle, rotate the antenna azimuth from 0°, and read the image level reading M at every set angle. i and the measurement and control antenna azimuth encoder reading A i Once, until the angle requirement is met, and find the maximum tilt direction A of the disk m and the maximum tilt δ i ; Correct the unevenness of the plate by adjusting the leveling mechanism, and then repeat this step until the maximum unevenness of the plate meets the preset accuracy Among them, the maximum value of the disk's unevenness is the maximum tilt corresponding to the maximum tilt azimuth.

[0024] Furthermore, the preset precision of the large disk level rough adjustment Equal to the leveling accuracy of the leveling mechanism, fine adjustment accuracy Less than the inertial navigation accuracy.

[0025] The beneficial effects of the above technical solution of the present invention are:

[0026] 1. The present invention solves the problem of inertial navigation calibration in a vehicle-carrying maneuvering environment, laying a foundation for realizing maneuverable measurement and control.

[0027] 2. The present invention can be implemented around the clock and is not affected by the climate environment.

[0028] 3. The present invention only requires one calibration antenna as a reference, which reduces the constraints on reference target conditions.

[0029] 4. The present invention obtains high-precision pointing information of the target through high-precision position measurement, thereby achieving higher inertial navigation calibration accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the inertial navigation calibration process of the mobile platform of the present invention.

[0031] Figure 2 It is a schematic diagram of the appearance of the mobile measurement and control platform of the present invention.

[0032] Figure 3 It is a structural schematic diagram of the mobile measurement and control platform of the present invention.

[0033] Figure 4 It is a schematic diagram of the principle of the inertial navigation calibration method of the mobile platform of the present invention.

[0034] Figure 5 It is a schematic diagram of the navigation coordinate system, vehicle coordinate system, and ENU coordinate system of the present invention.

[0035] Figure 6 It is a schematic diagram of the top view angle of the inertial navigation calibration of the present invention. DETAILED DESCRIPTION

[0036] The present invention will be further explained below in conjunction with the accompanying drawings.

[0037] The structure and appearance diagram of the mobile measurement and control platform are as follows: Figure 2 and Figure 3 As shown,

[0038] A mobile measurement and control platform inertial navigation calibration device, comprising a carrier, a beacon, a leveling mechanism 4, a shelter 5, a measurement and control antenna 6, an inertial navigation 7, a low-light television 8, a measurement and control device and a calibration antenna 10, wherein the carrier comprises a tractor 1 and a semi-trailer 2;

[0039] A leveling mechanism 4 is installed around the chassis of the semi-trailer 2; a square cabin 5 is installed on the semi-trailer 2, including an equipment cabin 11 and an antenna cabin 12; a measurement and control antenna 6 is installed in the antenna cabin 12 and is fixedly connected to the chassis of the semi-trailer 2; an inertial navigation system 7 is installed on an inertial navigation installation platform on the side of the sleeve of the measurement and control antenna 6; a low-light television 8 is installed behind the measurement and control antenna 6, with the lens facing the direction of the antenna's incoming waves; the measurement and control equipment is installed in the equipment cabin 11, including a measurement and control equipment cabinet 9 and an operating table 13; a beacon machine and a calibration antenna 10 are located in the far field area outside the vehicle.

[0040] Among them, the vehicle chassis is firmly connected to the measurement and control antenna 6, and the azimuth rotation platform of the measurement and control antenna 6 is parallel to the vehicle chassis; the inertial navigation 7 is installed on the inertial navigation installation platform, the inertial navigation installation platform of the inertial navigation 7 is firmly connected to the measurement and control antenna 6, and when the measurement and control antenna 6 is erected, the inertial navigation installation platform of the inertial navigation 7 is parallel to the azimuth rotation platform of the measurement and control antenna 6.

[0041] like Figure 4 As shown, the beacon and calibration antenna 10 are placed in the far field of the antenna, and can be placed on the calibration pole 3 at the front of the vehicle, the calibration tower or other high ground that meets the calibration conditions, such as a mountain top, a building top, etc.;

[0042] The principle of inertial navigation calibration is as follows Figure 1 As shown. The following steps are included:

[0043] 1. Place the vehicle on a hard surface, turn off the engine and keep it stationary, and roughly level the chassis. By adjusting the leveling mechanism, make the chassis of the vehicle level, that is, the horizontal plane X of the vehicle coordinate system b O b Y b Horizontal plane X with navigation coordinate system n O n Y n Parallel, the horizontal accuracy of the disk after adjustment is better than the preset accuracy Generally, it is the leveling accuracy of the large plate. In a certain measurement and control system, the leveling accuracy of the large plate is about 0.05° (i.e. 180″);

[0044] 2. Through geodetic measurement and calculation based on the vehicle structure parameters, the coordinates of the telemetry antenna phase center in the ENU coordinate system [x n1 ,y n1 ,z n1 ], generally speaking, the ENU coordinate system is different from the navigation coordinate system X n Y n Z n Overlap, such as Figure 5 As shown;

[0045] 3. Use the level gauge to fine-tune the level of the disk to ensure that the level accuracy of the disk meets the preset accuracy. The specific method is as follows: place an image level on the azimuth turntable platform of the measurement and control antenna, with the knob end of the image level facing the azimuth rotation center, and fix the antenna elevation angle; start from 0°, rotate the antenna azimuth, and read the image level reading M every 15° i and azimuth encoder reading A i Once, until 345°; sort out the data and find out the maximum tilt direction A of the disk m and the maximum tilt δ i ; The unevenness of the plate can be corrected by adjusting the leveling mechanism, and then repeat this step until the maximum unevenness of the plate meets the preset accuracy. The maximum value of the disk's non-levelness is the maximum tilt corresponding to the maximum tilt azimuth; Should be less than the inertial navigation heading accuracy φ e In a certain measurement and control system, the navigation heading accuracy is less than 20″, and the image level accuracy is less than 10″, which can meet the requirements;

[0046] 4. Turn on the inertial navigation system for coarse and fine alignment to obtain the attitude matrix of the inertial navigation coordinate system and the navigation coordinate system, that is, the inertial navigation heading angle φ, pitch angle θ and roll angle γ. At this time, the pitch angle and roll angle data are approximately 0°, that is, θ≈0°, γ≈0°;

[0047] 5. As Figure 4 As shown in the figure, the beacon and calibration antenna are placed in the far field of the antenna, which can be placed on the calibration pole at the front of the vehicle, the calibration tower or other high ground that meets the calibration conditions, such as the top of a mountain, the top of a building, etc. Use a low-light television to align the measurement and control antenna with the direction of the far-field calibration antenna, and measure the coordinates of the center of the calibration antenna in the ENU coordinate system [x n2 ,y n2 ,z n2 ]; The beacon is turned on and the calibration signal is transmitted through the far-field calibration antenna;

[0048] 6. The measurement and control equipment is set to capture and track mode. The measurement and control antenna captures the calibration signal and switches to tracking mode. At this time, the center of the measurement and control antenna's electrical axis is aligned with the calibration antenna. Read the value φ1 of the measurement and control antenna's azimuth encoder, that is, the angle between the measurement and control antenna's pointing azimuth and the vehicle coordinate system's azimuth 0°, such as Figure 6 As shown;

[0049] 7. Correct the attitude matrix of the inertial navigation output so that the inertial navigation coordinate system coincides with the vehicle coordinate system. Specifically, correct the pitch and roll angles of the inertial navigation output to 0°, that is, θ = 0°, γ = 0°, and correct the heading angle of the inertial navigation output to φ2-φ1, where φ2 is the vector of the line connecting the vehicle and the calibration antenna in the horizontal plane X of the navigation coordinate system. n O n Y n The angle between the projection and the navigation coordinate system azimuth 0° (i.e. due north), η=atan2(y n2 -y n1 ,x n2 -x n1 )×180 / π;

[0050] 8. Measure or calculate the three-dimensional coordinates of the phase center of the measurement and control antenna and the inertial navigation center, including longitude, latitude and altitude, and correct the inertial navigation position information so that the inertial navigation output position center coincides with the phase center of the measurement and control antenna.

[0051] The calibration antenna should generally meet the far-field condition, that is, the distance between the calibration antenna and the measurement and control antenna is greater than 2D. 2 / λ, where D is the diameter of the measurement and control antenna and λ is the carrier wavelength of the calibration signal. If the conditions are difficult to meet, the distance should not be less than D 2 / 2λ. The calibration antenna can be placed on a vehicle-mounted calibration pole, calibration tower or other high ground.

[0052] The position measurement of the vehicle-mounted measurement and control antenna and the calibration antenna can be carried out by differential GPS, total station and other methods. The azimuth error caused by the positioning error should be lower than the inertial navigation heading accuracy, that is, the position error Where L is the distance between the calibration antenna and the measurement and control antenna in the horizontal plane X of the navigation coordinate system. n O n Y n The projection distance, φ e is the inertial navigation accuracy, in arc seconds.

[0053] Through the above method, high-precision inertial navigation calibration can be achieved on the vehicle-mounted mobile platform.

Claims

1. A mobile measurement and control platform inertial navigation calibration method based on a mobile measurement and control platform inertial navigation calibration device, the device comprising a carrier, a beacon, a leveling mechanism (4), a shelter (5), a measurement and control antenna (6), an inertial navigation (7), a low-light television (8), a measurement and control device and a calibration antenna (10), wherein the carrier comprises a tractor (1) and a semitrailer (2); the semitrailer (2) is provided with a leveling mechanism (4) around its chassis; the shelter (5) is installed on the semitrailer (2), and comprises an equipment cabin (11 ) and an antenna cabin (12); a measurement and control antenna (6) is installed in the antenna cabin (12) and is fixedly connected to the chassis of a semitrailer (2); an inertial navigation (7) is installed on an inertial navigation installation platform on the side of a sleeve of the measurement and control antenna (6); a low-light television (8) is installed behind the measurement and control antenna (6), with the lens facing the direction of the antenna wave; the measurement and control equipment includes a measurement and control equipment cabinet (9) and an operating table (13), which are installed in the equipment cabin (11); a beacon machine and a calibration antenna (10) are located in a far field area outside the vehicle; it is characterized in that, The following steps are involved: Step 1: Place the vehicle on a hard surface and keep it stationary. Adjust the leveling mechanism to make the vehicle chassis level, that is, the horizontal plane X of the vehicle coordinate system. b O b Y b Horizontal plane X with navigation coordinate system n O n Y n Parallel, so that the horizontal accuracy of the disk after adjustment is better than the preset accuracy Step 2: Obtain the coordinates of the center of the telemetry antenna in the ENU coordinate system through geodetic measurement and calculation of the vehicle structure parameters [x n1 ,y n1 ,z n1 ]; Among them, the ENU coordinate system and the navigation coordinate system X n Y n Z n coincide; Step 3: Use the image level to fine-tune the level of the disk to make the level accuracy of the disk meet the preset accuracy. Step 4: Turn on the inertial navigation system for coarse alignment and fine alignment to obtain the attitude matrix of the inertial navigation coordinate system and the navigation coordinate system, namely, the inertial navigation heading angle φ, pitch angle θ and roll angle γ; Step 5: Place the beacon and calibration antenna in the far field of the antenna, use a low-light television to align the measurement and control antenna with the direction of the far-field calibration antenna, and measure the coordinates of the calibration antenna center in the ENU coordinate system [x n2 ,y n2 ,z n2 ]; At the same time, the beacon transmits the calibration signal through the far-field calibration antenna; Step 6: The measurement and control equipment is set to the capture and tracking mode. The measurement and control equipment controls the measurement and control antenna to capture and track. The measurement and control antenna captures the calibration signal and switches to the tracking mode. At this time, the center of the electrical axis of the measurement and control antenna is aligned with the calibration antenna. The value φ1 of the measurement and control antenna azimuth encoder is read out, that is, the angle between the measurement and control antenna pointing azimuth and the vehicle coordinate system azimuth 0°. Step 7, correct the attitude matrix output by the inertial navigation system to make the inertial navigation coordinate system coincide with the vehicle coordinate system. Specifically, first, correct the pitch angle and roll angle output by the inertial navigation system to 0°, that is, θ = 0°, γ = 0°, and then correct the heading angle output by the inertial navigation system to φ2-φ1; where φ2 is the vector of the line connecting the phase center of the measurement and control antenna and the calibration antenna in the horizontal plane X of the navigation coordinate system. n O n Y n The angle between the projection and the navigation coordinate system azimuth 0°, η=atan2(y n2 -y n1 ,x n2 -x n1 )×180 / π; Step 8, measure or calculate the three-dimensional coordinates of the phase center of the measurement and control antenna and the inertial navigation center, including longitude, latitude and altitude, and correct the inertial navigation position information so that the inertial navigation output position center coincides with the phase center of the measurement and control antenna.

2. The method for calibrating the inertial navigation system of a mobile measurement and control platform according to claim 1, characterized in that: Step 3: Place an image level on the azimuth turntable platform of the measurement and control antenna, with the knob end of the image level facing the azimuth rotation center, fix the antenna elevation angle, rotate the antenna azimuth from 0°, and read the image level reading M at every set angle. i and the measurement and control antenna azimuth encoder reading A i Once, until the angle requirement is met, and find the maximum tilt direction A of the disk m and the maximum tilt δ i ; Correct the unevenness of the plate by adjusting the leveling mechanism, and then repeat this step until the maximum unevenness of the plate meets the preset accuracy Among them, the maximum value of the disk's unevenness is the maximum tilt corresponding to the maximum tilt azimuth.

3. The method for calibrating the inertial navigation system of a mobile measurement and control platform according to claim 1, characterized in that: The preset accuracy of the large plate horizontal coarse adjustment Equal to the leveling accuracy of the leveling mechanism, fine adjustment accuracy Less than the inertial navigation accuracy.

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