Measurement, verification, method and device for initial alignment accuracy of launch vehicles

Abstract

This invention relates to the field of rocket technology, and more particularly to a method and apparatus for measuring and verifying the initial alignment accuracy of a launch vehicle. The method includes an initial alignment accuracy adjustment device for the launch vehicle, comprising an inertial navigation system (INS) and a differential orientation system (DIS). The method includes: acquiring the initial alignment attitude angle measured by the INS and the azimuth angle output by the DIS; the initial alignment attitude angle represents the attitude angle of the launch vehicle relative to the navigation coordinate system before launch, and the azimuth angle represents the direction angle of the launch vehicle relative to the Earth's fixed coordinate system during the initial alignment process; obtaining the initial alignment direction angle error based on the initial alignment attitude angle and azimuth angle; and adjusting the initial alignment accuracy of the launch vehicle according to the initial alignment direction angle error value. This invention overcomes the limitations of the measurement environment and enables rapid measurement of the initial alignment direction angle error of the INS under swaying conditions.

Description

Technical Field

[0001] This invention relates to the field of rocket technology, and in particular to a method and apparatus for measuring and verifying the initial alignment accuracy of a launch vehicle. Background Technology

[0002] Inertial navigation is a fully autonomous recursive navigation system that requires prior knowledge of the initial state variables. The initial alignment of a launch vehicle uses the angle information measured by the gyroscope and known information to determine the initial attitude of the rocket body in the navigation coordinate system, providing the prerequisite for subsequent precision guidance.

[0003] However, current measurement methods cannot adapt to the complex swaying environment of sea-based alignment. Sea-based launches are more complex than land-based launches, with the rocket body constantly swaying, which places higher demands on the initial alignment algorithm. Summary of the Invention

[0004] This invention provides a measurement and verification method and apparatus for the initial alignment accuracy of a launch vehicle, which solves one of the defects in the prior art. This invention overcomes the limitations of the measurement environment and can realize the rapid measurement of the initial alignment direction angle error of the inertial navigation system under shaking conditions.

[0005] This invention provides a method for measuring and verifying the initial alignment accuracy of a launch vehicle, applied to a launch vehicle initial alignment accuracy adjustment device. The launch vehicle initial alignment accuracy adjustment device includes an inertial navigation system and a differential orientation system, comprising:

[0006] The initial alignment attitude angle measured by the inertial navigation system and the azimuth angle output by the differential orientation system are obtained; the initial alignment attitude angle represents the attitude angle of the launch vehicle relative to the navigation coordinate system before launch, and the azimuth angle represents the orientation angle of the launch vehicle relative to the Earth fixed coordinate system during the initial alignment process.

[0007] Based on the initial alignment attitude angle and the azimuth angle, the initial alignment direction angle error is obtained;

[0008] The initial alignment accuracy of the launch vehicle is adjusted based on the initial alignment direction angle error value.

[0009] According to the present invention, a method for measuring and verifying the initial alignment accuracy of a launch vehicle includes obtaining the initial alignment attitude angle measured by the inertial navigation system and the azimuth angle output by the differential orientation system, which comprises:

[0010] Acquire an initial alignment attitude angle signal set within a set time period. The elements of the initial alignment attitude angle signal set are an array composed of the initial alignment attitude angle measured by the inertial navigation system and a first time, where the first time is the moment when the initial alignment attitude angle is acquired within the set time period.

[0011] Obtain the set of differential orientation output signals within the set time period. The elements of the differential orientation output signal set are an array composed of the azimuth angle output by the differential orientation and the second time, where the second time is the moment when the azimuth angle output by the differential orientation is obtained within the set time period.

[0012] According to the present invention, a method for measuring and verifying the initial alignment accuracy of a launch vehicle is provided, wherein obtaining the initial alignment direction angle error based on the initial alignment attitude angle and azimuth angle includes:

[0013] The initial alignment attitude angle signal set is processed based on the second time to obtain the inertial navigation system output signal set at the second time.

[0014] Based on the set of inertial navigation system output signals and the set of differential orientation system output signals corresponding to the second time, an array of the initial alignment measurement error as a function of time is obtained.

[0015] According to the present invention, a method for measuring and verifying the initial alignment accuracy of a launch vehicle, wherein processing the initial alignment attitude angle signal set based on a second time to obtain the inertial navigation system output signal set at the second time includes:

[0016] The set of inertial navigation system output signals for the second time is obtained by performing linear interpolation on the initial alignment attitude angle signal set at the second time.

[0017] According to the present invention, a method for measuring and verifying the initial alignment accuracy of a launch vehicle, wherein obtaining an array of initial alignment measurement errors changing over time based on the set of inertial navigation system output signals and the set of differential direction finder output signals corresponding to a second time includes:

[0018] By subtracting the set of inertial navigation system output signals and the set of differential orientation system output signals at the same moment, an array of the initial alignment measurement error as a function of time is obtained.

[0019] The present invention also provides a launch vehicle initial alignment accuracy measurement and verification device, characterized in that it performs the launch vehicle initial alignment accuracy measurement and verification method as described above, including an inertial navigation system, a differential orientation system and a simulator, wherein the inertial navigation system includes at least one measurement axis, the differential orientation system includes at least one set of antennas, the antennas are arranged parallel to at least one of the measurement axes, and both the inertial navigation system and the differential orientation system are connected to the simulator.

[0020] According to the present invention, a launch vehicle initial alignment accuracy measurement and verification device further includes a fixing fixture, wherein the inertial navigation system and the antenna are both disposed on the fixing fixture.

[0021] According to the present invention, a launch vehicle initial alignment accuracy measurement and verification device is provided. The fixed fixture includes a base frame and a first mounting part and at least a pair of second mounting parts disposed on the base frame. The first mounting part is adapted to mount an inertial navigation system (INS). Each pair of second mounting parts is adapted to mount a set of antennas of a differential directional device. The first mounting part is located between the two second mounting parts. The center line connecting the two second mounting parts is adapted to be parallel to the measurement axis of the INS during initial measurement.

[0022] According to the present invention, a launch vehicle initial alignment accuracy measurement and verification device is provided. The first mounting part includes a support base and a turntable. The support base is connected to the turntable. The support base is adapted to mount the inertial navigation system (INS). The turntable is provided with at least four first adjustment holes. The first adjustment holes are connected to the base frame by fasteners. The first adjustment holes are evenly distributed around the INS in the circumferential direction.

[0023] According to the present invention, a launch vehicle initial alignment accuracy measurement and verification device is provided, wherein the support base is provided with at least four second adjustment holes, the second adjustment holes being arranged in a one-to-one correspondence with the first adjustment holes, and the second adjustment holes being connected to the first adjustment holes by fasteners.

[0024] The initial alignment accuracy measurement and verification method for launch vehicles in this embodiment of the invention connects a simulator, a differential orientation device (DIDD), a fiber optic inertial navigation system (INS), and a regulated DC power supply via a simulator cable. After the telemetry and control system is integrated and debugged, the equipment is powered on, and the simulator acquires the outputs of the INS and the DIDD in real time. Specifically, the attitude angle of the launch vehicle relative to the navigation coordinate system before launch, measured by the INS, is used as the initial alignment attitude angle, and the direction angle of the launch vehicle relative to the Earth's fixed coordinate system, output by the DIDD, is used as the azimuth angle. By comprehensively comparing and processing the initial alignment attitude angle and azimuth angle, the initial alignment direction angle error is obtained, achieving the goal of rapid measurement of the initial alignment direction angle error of the INS under shaking conditions. Based on the initial alignment direction angle error, the initial alignment parameters can be adjusted to improve alignment accuracy. The measurement results measured by the INS and the DIDD complement each other. The INS provides high-precision short-term dynamic measurement, while the DIDD provides a long-term stable reference direction, which can effectively reduce the impact of measurement errors from a single device. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1This is one of the structural schematic diagrams of the fixing fixture provided in the embodiments of the present invention;

[0027] Figure 2 This is a second schematic diagram of the structure of the fixing fixture provided in the embodiment of the present invention;

[0028] Figure 3 This is the third schematic diagram of the structure of the fixing fixture provided in the embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram of the structure of the initial alignment accuracy measurement and verification device for launch vehicles provided in an embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram of the structure of the electronic device provided in an embodiment of the present invention;

[0031] Figure 6 This is a flowchart of the initial alignment accuracy measurement and verification method for launch vehicles provided in an embodiment of the present invention.

[0032] Figure label:

[0033] 100. Inertial navigation system; 200. Differential direction finder; 210. Antenna;

[0034] 300. Simulator;

[0035] 400. Fixture; 410. Base frame; 411. Fixing hole; 412. Handle; 420. First mounting part; 421. Support base; 4211. Base; 4212. Protrusion; 4213. Second adjustment hole; 422. Turntable; 4222. Base plate; 4223. Vertical plate; 4224. Connecting plate; 4225. Triangular plate; 430. Second mounting part;

[0036] 500, power supply;

[0037] 810, Processor; 820, Communication interface; 830, Memory; 840, Communication bus. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0039] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0040] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0041] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0042] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0043] The present invention relates to the field of hardware-in-the-loop simulation of launch vehicle inertial navigation systems. In the initial alignment hardware-in-the-loop simulation experiment based on fiber optic inertial navigation systems (hereinafter referred to as inertial navigation systems), this method can quickly verify the accuracy of the output results of the inertial navigation system initial alignment algorithm, providing physical reference data for the design and optimization of the initial alignment algorithm in the launch vehicle inertial navigation system, and helping to improve the accuracy and stability of the initial alignment algorithm of launch vehicles in dynamic environments.

[0044] The inertial navigation system (INS) is the core component of a launch vehicle's inertial navigation system, primarily composed of three mutually perpendicular accelerometers and gyroscopes. Inertial navigation is a fully autonomous, recursive navigation system that requires prior knowledge of the initial state variables. The initial alignment of the launch vehicle utilizes the angle information sensed by the gyroscopes and known information to determine the initial attitude of the rocket body in the navigation coordinate system, providing the prerequisite for subsequent precision guidance. Sea-based launches are more complex than land-based launches, with the rocket body constantly in a state of motion. This places higher demands on the initial alignment algorithm; therefore, when designing the initial alignment algorithm, it is necessary to measure the initial alignment error under motion conditions.

[0045] Currently, most methods for measuring the initial alignment accuracy of inertial navigation systems (INS) are performed on a static base, such as a three-axis turntable. The INS is mounted on the turntable, ensuring that the three measurement axes of the INS are parallel to the rotation axes of the turntable. The initial alignment result is then compared with the orientation of the turntable axes to calculate the initial alignment error.

[0046] Existing methods for measuring initial alignment errors of inertial navigation systems (INS) are mostly performed on static bases, which cannot adapt to the complex swaying environment of sea-based alignment. To address this issue, this invention provides a method and device for adjusting the initial alignment accuracy of a launch vehicle.

[0047] like Figure 1 , Figure 2 and Figure 4 As shown, the fixed fixture 400 provided in this embodiment of the invention includes a base frame 410 and a first mounting portion 420 and at least one pair of second mounting portions 430 disposed on the base frame 410. The first mounting portion 420 is adapted to mount the inertial navigation system 100. Each pair of second mounting portions 430 is adapted to mount a set of antennas 210 of the differential direction finder 200. The first mounting portion 420 is located between the two second mounting portions 430. The center line connecting the two second mounting portions 430 is adapted to be parallel to the measurement axis of the inertial navigation system 100 during the initial measurement.

[0048] The fixing fixture 400 of this invention is used for measuring and verifying the initial alignment accuracy of a launch vehicle at sea. The fixing fixture 400 mainly consists of a base frame 410, a first mounting part 420, and at least one pair of second mounting parts 430. The first mounting part 420 positions the inertial navigation system 100, and the second mounting parts 430 position the antennas 210 of the differential direction finder 200. After the inertial navigation system 100 has performed multiple measurements, the differential direction finder 200 has at least one set of antennas 210, and each set of antennas 210 includes two antennas 210. The pair of second mounting parts 430 correspondingly fixes one set of antennas 210. 0. The two second mounting parts 430 are located on both sides of the first mounting part 420. The center line connecting the two second mounting parts 430 is parallel to the state of one measurement axis of the inertial group 100 at the first mounting part 420 during the initial measurement. This orientation can be used as a test reference, that is, to ensure that one measurement axis of the inertial group 100 is parallel to a set of antennas 210 of the differential directional device 200 during the initial measurement. This satisfies the requirement that when the inertial group 100 is installed on the fixed fixture 400, one measurement axis of the inertial group 100 must be parallel to the straight line where the set of antennas 210 of the differential directional device 200 are located.

[0049] During the initial alignment accuracy measurement and verification of the launch vehicle at sea, it is necessary to obtain the azimuth angles of the inertial navigation system 100 and the differential orientation device 200. The fixed fixture 400 of the present invention can ensure the attitude of the inertial navigation system 100 and the differential orientation device 200 during the measurement and verification, thereby ensuring the measurement accuracy and precision, overcoming the limitations of the measurement environment, and realizing the rapid measurement of the initial alignment direction angle error of the inertial navigation system 100 under shaking conditions.

[0050] In this embodiment, the base frame 410 is configured as a long, symmetrical structure with a first mounting portion 420 in the middle and a second mounting portion 430 at each end, forming a pair of second mounting portions 430. The vertical distance between the first mounting portion 420 and the two second mounting portions 430 is equal. The symmetrical design of the base frame 410 facilitates its integration with other components. In other embodiments, the number of pairs of second mounting portions 430 can be set according to the actual number of antenna groups 210 in the differential directional antenna 200, and the shape of the base frame 410 can be asymmetrical, meaning that the vertical distance between the first mounting portion 420 and each of the second mounting portions 430 can be different.

[0051] In this embodiment, the second mounting part 430 is a mounting hole formed on the base frame 410. In other embodiments, the second mounting part 430 may also be other mounting and fixing structures.

[0052] According to one embodiment of the present invention, the first mounting part 420 is detachably connected to the base frame 410, and is adapted to adjust the angle between the measurement axis of the inertial navigation system 100 and the center line. In this embodiment, the first mounting part 420 can be rotated and adjusted on the base frame 410 by disassembly, thereby adjusting the angle between the measurement axis of the inertial navigation system 100 fixed on the first mounting part 420 and the antenna 210 fixed on the second mounting part 430.

[0053] During the initial alignment accuracy measurement and verification of the launch vehicle at sea, the azimuth angles of the inertial navigation system 100 and the differential direction finder 200 are obtained when the measurement axis is parallel to the antenna 210. In subsequent measurements, the angle between the measurement axis and the antenna 210 needs to be adjusted, the first mounting part 420 is separated from the base frame 410, the state of the first mounting part 420 is adjusted, and then the first mounting part 420 is connected to the base frame 410. This adjusts the angle between the measurement axis and the antenna 210, and the subsequent alignment algorithm is executed in sequence. At the same time, the azimuth angle error of the initial alignment of the inertial navigation system 100 under different azimuths can be determined.

[0054] According to an embodiment of the present invention, the first mounting part 420 includes a support base 421 and a turntable 422. The support base 421 is connected to the turntable 422. The support base 421 is adapted to mount the inertial group 100. The turntable 422 is provided with at least four first adjustment holes. The first adjustment holes are connected to the base frame 410 by fasteners. The first adjustment holes are evenly distributed around the inertial group 100 in the circumferential direction.

[0055] In this embodiment, the first mounting part 420 consists of a support base 421 and a turntable 422. The support base 421 is used to fix the inertial group 100, and the turntable 422 is used to connect the support base 421 to the base frame 410. At least four first adjustment holes are provided on the turntable 422. The distribution of the first adjustment holes is evenly arranged around the inertial group 100, that is, the maximum central angle between two adjacent first adjustment holes is 90°. The central angle spacing of the first adjustment holes is set according to the actual orientation adjustment requirements of the measurement axis. For example, if the adjustment is 60° each time, six first adjustment holes are provided. If the adjustment is 30° each time, 12 first adjustment holes are provided.

[0056] By setting the first adjustment hole on the turntable 422, it can be ensured that after the turntable 422 rotates through a fixed angle and is fixed to the base frame 410 by fasteners, the measuring axis of the inertial navigation system 100 on the support base 421 will precisely rotate through the adjustment angle. The design of the fixed fixture 400 is simple and the composition is simple, but the measurement accuracy can meet the design requirements.

[0057] In this embodiment, the fastener can be selected as a bolt or a screw, and the base frame 410 is provided with a corresponding threaded connection hole corresponding to the first adjustment hole.

[0058] According to one embodiment of the present invention, the support base 421 includes a base 4211 and a protrusion 4212. One side of the base 4211 contacts the turntable 422, and the other side is provided with the protrusion 4212, which encloses a space suitable for mounting the inertial navigation system 100. In this embodiment, the support base 421 mainly consists of the base 4211 and the protrusion 4212. The base 4211 serves as the basic support for the inertial navigation system 100 and also connects to the turntable 422. The protrusion 4212 is annular and extends vertically upward from the upper surface of the base 4211. The inertial navigation system 100 can be fixed in the protrusion 4212 or in the space enclosed by the protrusion 4212.

[0059] In this embodiment, the protrusion 4212 surrounds a square receiving cavity, and the base 4211 is a circular base 4211. The square receiving cavity is used to accommodate the inertial group 100 and can be fixed to the inertial group 100 by bolts. In other embodiments, the receiving cavity can also be of other shapes, as long as it is adapted to the shape of the inertial group 100 used.

[0060] According to one embodiment of the present invention, the support base 421 is provided with at least four second adjustment holes 4213, each corresponding to a first adjustment hole, and the second adjustment holes 4213 and the first adjustment holes are connected by fasteners. In this embodiment, the support base 421 and the turntable 422 can also be connected in an adjustable manner, that is, the support base 421 is also provided with second adjustment holes 4213, each corresponding to a first adjustment hole, and the support base 421 and the turntable 422 are connected by fasteners to connect the second adjustment holes 4213 and the first adjustment holes.

[0061] The second adjustment holes 4213 are evenly distributed around the inertial navigation system 100, that is, the maximum central angle between two adjacent second adjustment holes 4213 is 90°. The spacing between the central angles of the second adjustment holes 4213 is set according to the actual orientation adjustment requirements of the measurement axis. For example, if the adjustment is 60° each time, six second adjustment holes 4213 are set; if the adjustment is 30° each time, 12 second adjustment holes 4213 are set.

[0062] After the support base 421 is removed from the turntable 422, rotating the support base 421 can adjust its relative state on the turntable 422, thereby adjusting the angle between the inertial group 100 on the support base 421 and the antenna 210. Through the setting of the second adjustment hole 4213 on the support base 421, it can be ensured that after the support base 421 is rotated through a fixed angle and fixed to the turntable 422 by fasteners, the measurement axis of the inertial group 100 on the support base 421 is precisely rotated through the adjustment angle. The design of the fixing fixture 400 is simple and the composition is simple, but the measurement accuracy can meet the design requirements.

[0063] In this embodiment, the fastener can be a bolt or a screw. The base frame 410 is provided with a corresponding threaded connection hole corresponding to the first adjustment hole, and then the support base 421, turntable 422 and base frame 410 are connected and fixed in sequence from top to bottom by the fastener.

[0064] The second adjustment hole 4213 can be set on the base 4211, that is, on the plane where the base frame 410 is located. The base 4211 and the turntable 422 both have adjustment holes with different rotation angles. By rotating the base 4211 and the turntable 422, the angle of the inertial group 100 can be adjusted as needed, thereby determining the alignment accuracy of the inertial group 100 in other orientations.

[0065] Furthermore, to improve the initial alignment direction angle error, two or three sets of antennas 210 of the differential direction finder 200 can be used, with each set of antennas 210 parallel to one measurement axis of the inertial navigation system 100. By aligning multiple sets of antennas 210 parallel to the measurement axes, multiple error values ​​can be obtained simultaneously, thereby improving the final measurement accuracy.

[0066] like Figure 3 As shown, according to an embodiment of the present invention, the turntable 422 includes a base plate 4222, a vertical plate 4223, a connecting plate 4224, and a triangular plate 4225. The base plate 4222 is provided with a first adjustment hole, which is suitable for connection with the base frame 410. The vertical plate 4223 is vertically connected to the base plate 4222 through the triangular plate 4225. The connecting plate 4224 is disposed on the vertical plate 4223. The connecting plate 4224 is provided with a third adjustment hole that corresponds one-to-one with the second adjustment hole 4213, which is suitable for connecting the connecting plate 4224 to the support base 421.

[0067] Due to the shape of the inertial navigation system 100 itself, after the support base 421 is installed with the inertial navigation system 100, a set of antennas 210 is parallel to one of the fixed measurement axes of the inertial navigation system 100 and cannot be changed. Therefore, in order to change the measurement axis of the inertial navigation system 100 that is parallel to the antenna 210, the structure of the support base 421 was further designed.

[0068] In this embodiment, the turntable 422 mainly consists of a base plate 4222, a vertical plate 4223, a connecting plate 4224, and two triangular plates 4225. The base plate 4222 is connected to the base frame 410, and the two triangular plates are fixed on the base plate 4222. The vertical plate 4223 is then fixed by the two triangular plates, thus making the vertical plate 4223 perpendicularly connected to the base plate 4222. The connecting plate 4224 is set on the vertical plate 4223, and the base 4211 of the support seat 421 is connected to the connecting plate 4224. At this time, a first adjustment hole is provided on the base plate 4222. Rotating the base plate 4222 will drive the vertical plate 4223 and the support seat 421 to rotate, thereby realizing the relative angle adjustment between the turntable 422 and the base plate 4222. A third adjustment hole is provided on the connecting plate 4224, which corresponds to the second adjustment hole 4213, to realize the relative angle adjustment between the support seat 421 and the turntable 422, thereby realizing the orientation adjustment of the measuring axis. By adjusting the position of the upright plate 4223, the dual antennas 210 and the inertial group 100 can be made parallel after different measurements. The fixed fixture 400, through combination design, can obtain the alignment error of the inertial group 100 under different measurement axes and different orientations.

[0069] According to one embodiment of the present invention, the base frame 410 is provided with a fixing hole 411 suitable for connection with a mounting surface. In this embodiment, a fixing hole 411 is provided at a position between the first mounting part 420 and the second mounting part 430 on the base frame 410. The fixing hole 411 is used to fix the base frame 410 to the ground, ground facilities, test stand, launch vehicle, launch ship, etc.

[0070] In this embodiment, the fixing hole 411 can be a screw hole, which can be fastened by bolts or the like.

[0071] According to one embodiment of the present invention, the base frame 410 is provided with a handle 412. In this embodiment, a handle 412 is provided at the position between the fixing hole 411 and the second mounting part 430 on the base frame 410. The operator can grasp the entire fixing fixture 400 through the handle 412, which facilitates the disassembly, assembly, position adjustment and transportation of the fixing fixture 400.

[0072] The fixing fixture 400 of this invention enables the measurement axis of the inertial navigation system 100 to be parallel to the antenna 210 of the differential direction finder 200, combining the measurement data of the inertial navigation system 100 and the differential direction finder 200 to more accurately measure the error. The overall structure is simple, low-cost, lightweight, and easy to assemble, disassemble, and transport.

[0073] The initial alignment accuracy measurement and verification device for launch vehicles provided by the present invention is described below. The initial alignment accuracy measurement and verification device for launch vehicles described below can be referred to in correspondence with the tooling described above.

[0074] This invention also provides a launch vehicle initial alignment accuracy measurement and verification device, including an inertial navigation system 100, a differential directional device 200, and a fixed fixture 400 as described above. The inertial navigation system 100 is disposed in a first mounting part 420, and the differential directional device 200 includes at least one set of antennas 210, which are disposed in a second mounting part 430.

[0075] The initial alignment accuracy measurement and verification device for launch vehicles in this embodiment of the invention uses an inertial navigation system (INS) 100, which is the core component of the launch vehicle's inertial navigation system. It mainly consists of three mutually perpendicular accelerometers and gyroscopes. Inertial navigation is a fully autonomous recursive navigation system that requires prior knowledge of the initial state variables. The initial alignment of the launch vehicle utilizes the angle information sensed by the gyroscopes and known information to determine the initial attitude of the rocket body in the navigation coordinate system, providing the prerequisite for subsequent precision guidance.

[0076] The initial alignment accuracy measurement and verification device for a launch vehicle provided by the present invention further includes a simulator 300, and the inertial navigation system 100 and the differential orientation device 200 are both connected to the simulator 300.

[0077] The initial alignment accuracy measurement and verification device for a launch vehicle according to this invention comprises a fixed fixture 400, an inertial navigation system (INS) 100, a differential orientation device (DIDD) 200, and a simulator 300. The INS 100 and DIDD 200 are fixedly connected via the fixture 400, ensuring that the measurement axis of the INS 100 is parallel to the dual antennas 210 of the DIDD 200. The simulator 300 is connected to the INS 100 and DIDD 200 via a simulation cable, enabling real-time acquisition of the azimuth angles of the INS 100 and DIDD 200. The simulator 300 outputs the initial alignment attitude angle in real-time by running an initial alignment algorithm. By comparing the initial alignment attitude angle with the azimuth angle of the DIDD 200, the initial alignment direction angle error is obtained, achieving the goal of rapid measurement of the initial alignment direction angle error of the INS 100 under swaying conditions.

[0078] This invention can be applied to the measurement and verification of the initial alignment accuracy of launch vehicles at sea. The environment of sea launch is more complex than that of land launch, and the rocket body is in a state of constant shaking. In addition, when designing the initial alignment algorithm, it is necessary to measure the initial alignment error under shaking conditions, which puts forward higher requirements for the initial alignment algorithm. This invention overcomes the limitations of the measurement environment and can realize the rapid measurement of the initial alignment direction angle error of the inertial navigation system 100 under shaking conditions.

[0079] This invention relates to the field of hardware-in-the-loop simulation of launch vehicle inertial navigation systems. In the initial alignment hardware-in-the-loop simulation experiment based on the participation of fiber optic inertial navigation system 100, this invention can quickly verify the accuracy of the output results of the initial alignment algorithm of inertial navigation system 100, provide physical reference data for the design and optimization of the initial alignment algorithm in the launch vehicle inertial navigation system, and help improve the accuracy and stability of the initial alignment algorithm of launch vehicle in dynamic environment.

[0080] The initial alignment accuracy measurement and verification method for launch vehicles provided by the present invention is described below. The initial alignment accuracy measurement and verification method for launch vehicles described below can be referred to in correspondence with the initial alignment accuracy measurement and verification device for launch vehicles described above.

[0081] like Figure 6 As shown, this embodiment of the invention also provides a method for measuring and verifying the initial alignment accuracy of a launch vehicle, applied to the launch vehicle initial alignment accuracy measurement and verification device as described in the above embodiment, comprising:

[0082] The initial alignment attitude angle measured by the inertial navigation system 100 and the azimuth angle output by the differential orientation system 200 are obtained. The initial alignment attitude angle represents the attitude angle of the launch vehicle relative to the navigation coordinate system before launch, and the azimuth angle represents the orientation angle of the launch vehicle relative to the Earth fixed coordinate system during the initial alignment process.

[0083] Based on the initial alignment attitude angle and azimuth angle, the initial alignment direction angle error is obtained;

[0084] Adjust the initial alignment accuracy of the launch vehicle based on the initial alignment direction angle error value.

[0085] The method for measuring and verifying the initial alignment accuracy of a launch vehicle in this embodiment of the invention connects the simulator 300, differential orientation device 200, fiber optic inertial navigation system 100, and regulated DC power supply 500 via a simulator cable. After the telemetry and control system is integrated and debugged, the equipment is powered on, and the simulator 300 collects the outputs of the inertial navigation system 100 and the differential orientation device 200 in real time. That is, the attitude angle of the launch vehicle relative to the navigation coordinate system before launch, measured by the inertial navigation system 100, is used as the initial alignment attitude angle, and the direction angle of the launch vehicle relative to the Earth's fixed coordinate system during the initial alignment process, output by the differential orientation device 200, is used as the azimuth angle.

[0086] By comprehensively comparing the initial alignment attitude angle and azimuth angle, the initial alignment direction angle error is obtained, achieving the goal of rapid measurement of the initial alignment direction angle error of the inertial navigation system 100 under shaking conditions. Based on the initial alignment direction angle error, the initial alignment parameters can be adjusted, thereby improving alignment accuracy. The measurement results from the inertial navigation system 100 and the differential orientation system 200 complement each other. The inertial navigation system 100 provides high-precision short-term dynamic measurement, while the differential orientation system 200 provides a long-term stable reference direction, which can effectively reduce the impact of measurement errors from a single device.

[0087] This invention uses a differential orientation unit 200 instead of a three-axis turntable. The structural components ensure that the dual antennas 210 of the differential orientation unit are parallel to the measurement axis of the inertial navigation system 100. The initial alignment direction angle error is obtained by comparing the initial alignment result of the inertial navigation system 100 with the differential orientation result, thus achieving the purpose of rapid measurement of the initial alignment direction angle error of the inertial navigation system 100 under shaking conditions.

[0088] According to an embodiment of the present invention, obtaining the initial alignment attitude angle measured by the inertial navigation system 100 and the azimuth angle output by the differential orientation system 200 includes:

[0089] Acquire the initial alignment attitude angle signal set within a set time period. The elements of the initial alignment attitude angle signal set are an array composed of the initial alignment attitude angle measured by the inertial navigation system 100 and the first time. The first time is the moment when the initial alignment attitude angle is acquired within the set time period.

[0090] Obtain the set of output signals of differential directional device 200 within a set time period. The elements of the set of output signals of differential directional device 200 are an array composed of the azimuth angle output by differential directional device 200 and the second time. The second time is the moment when the azimuth angle output by differential directional device 200 is obtained within the set time period.

[0091] In this embodiment, the simulator 300 acquires the outputs of the inertial navigation system 100 and the differential direction finder 200 in real time and records the corresponding signal arrival times. The acquisition times and the acquired signal data together form an array. The array obtained after continuous acquisition within a set time period serves as the elements of the array, i.e., the signal set. The set time can be a period of a certain length, or it can be one or more specific time points. The set can consist of one or more array elements.

[0092] After the above tests are completed, an array of initial alignment attitude angle signals (t_gz, gamma_gz) and an array of differential orientation 200 output signals (t_tx, gamma_tx) are obtained.

[0093] According to an embodiment of the present invention, the initial alignment direction angle error is obtained based on the initial alignment attitude angle and azimuth angle, including:

[0094] Based on the processing of the initial alignment attitude angle signal set at the second time, the output signal set of the inertial navigation system 100 at the second time is obtained;

[0095] Based on the set of output signals from the inertial navigation system 100 and the set of output signals from the differential orientation device 200 corresponding to the second time, an array of the initial alignment measurement error as a function of time is obtained.

[0096] In this embodiment, the initial alignment attitude angle signal set acquired by the inertial group 100 is processed, that is, the initial alignment attitude angle signal set is integrated into the second time to obtain the output signal set of the inertial group 100. In addition, the initial alignment attitude angle signal set in the first time is converted into the initial alignment attitude angle signal set in the second time. The initial alignment attitude angle signal set integrated into the same time period is compared with the output signal set of the differential orientation device 200 to obtain an array of the initial alignment measurement error changing with time.

[0097] In this embodiment, the second time can be a point in time within a plurality of second times, and the set of output signals obtained from the inertial group 100 can be the output signals of the inertial group 100 at that point in time. Alternatively, the second time can be all second times, that is, all the initial alignment attitude angle signals acquired by the inertial group 100 are converted into the set of output signals of the inertial group 100. The array of initial alignment measurement errors changing with time can be an array at one or more time points, or it can be a set of arrays within the entire second time range.

[0098] In other embodiments, the set of azimuth signals at a first time is processed to obtain the set of output signals of the differential orienter 200 at the first time; based on the set of output signals of the differential orienter 200 and the set of output signals of the inertial navigation system 100 corresponding to the first time, an array of the initial alignment measurement error changing over time is obtained.

[0099] The azimuth signal set acquired by the differential orientation unit 200 is processed by integrating the azimuth signal set into the first time to obtain the output signal set of the differential orientation unit 200. This also involves converting the azimuth signal set at the second time to the azimuth signal set at the first time. The azimuth signal set integrated into the unified time period is compared with the output signal set of the inertial navigation system 100 to obtain an array of the initial alignment measurement error changing over time.

[0100] In this embodiment, the first time can be a specific point in time among multiple first times, and the set of output signals obtained from the differential orientation device 200 can be the output signals of the differential orientation device 200 at that specific point in time. Alternatively, the first time can be any of the first times, meaning that all the azimuth signals acquired by the differential orientation device 200 are converted into the set of output signals from the differential orientation device 200. The array showing the change of the initial alignment measurement error over time can be an array at one or more time points, or it can be a set of arrays within the entire first time range.

[0101] Inertial navigation systems (INS) typically sample at higher frequencies (e.g., several hundred hertz), while differential direction finders (CDF) may sample at lower frequencies. Therefore, compared to processing INS data based on the timing of CDF data acquisition, directly interpolating low-frequency CDF data using high-frequency INS data may lead to increased interpolation errors, especially when data changes rapidly. To ensure that processing CDF data based on the timing of INS data acquisition also achieves the required accuracy, it is essential to synchronize the time bases of the INS and CDF before testing begins. This can be achieved using an external time synchronization signal (such as a GPS time signal).

[0102] According to an embodiment of the present invention, processing the initial alignment attitude angle signal set based on a second time to obtain the inertial navigation system 100 output signal set at the second time includes:

[0103] The set of inertial navigation system (INS) 100 output signals for the second time is obtained by performing linear interpolation calculation on the initial alignment attitude angle signal set at the second time.

[0104] In this embodiment, the second time t_tx is used to perform linear interpolation on the array (t_gz, gamma_gz) of the initial alignment attitude angle signal set to obtain the output signal (t_gz1, gamma_gz1) of the inertial navigation system 100 at the same time. At this time, t_tx = t_gz1.

[0105] According to an embodiment of the present invention, based on the set of output signals from the inertial navigation system 100 and the set of output signals from the differential orientation device 200 corresponding to a second time, an array of the initial alignment measurement error changing over time is obtained, including:

[0106] By subtracting the output signal set of inertial navigation system 100 and the output signal set of differential orientation system 200 at the same moment, an array of the initial alignment measurement error as a function of time is obtained.

[0107] In this embodiment, the azimuth angles are subtracted at the same time to obtain an array (t_tx, gamma_gz - gamma_tx) showing how the initial alignment measurement error changes over time.

[0108] In one embodiment, the time interval of the output data of the inertial navigation system 100 is different from the time interval of the output data of the differential direction finder 200, that is, the time interval of the first time is different from the time interval of the second time within a set time period.

[0109] For example, if the inertial navigation system 100 outputs data once every 100ms and the differential orientation system outputs data once every 10ms, then the two sets of data are obtained at different times, so the inertial navigation system data needs to be interpolated.

[0110] For example, at the second time of 150ms, the differential orientation unit 200 outputs the corresponding azimuth angle data, which can be obtained directly without interpolation; while the inertial navigation system 100 does not output the corresponding initial alignment attitude angle data at the second time of 150ms, and interpolation calculation is required to obtain the initial alignment attitude angle data at the same moment.

[0111] After obtaining the initial alignment attitude angle data of the inertial navigation system 100 and the azimuth angle data of the differential orientation system 200 at 150ms, the difference between the coordinate values ​​is calculated to obtain the initial alignment measurement error data at that moment. Based on this error value, the initial alignment parameters can be adjusted to improve the alignment accuracy.

[0112] Figure 5 A schematic diagram of the physical structure of an electronic device is provided. This electronic device may include a processor 810, a communications interface 820, a memory 830, and a communication bus 840. The processor 810, communications interface 820, and memory 830 communicate with each other via the communication bus 840. The processor 810 can call logical instructions from the memory 830 to execute a method for measuring and verifying the initial alignment accuracy of a launch vehicle.

[0113] Furthermore, the logical instructions in the aforementioned memory 830 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0114] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer is able to execute the initial alignment accuracy measurement and verification method for launch vehicles provided by the above methods.

[0115] In another aspect, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to perform the launch vehicle initial alignment accuracy measurement and verification method provided by the above methods.

[0116] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0117] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware tooling, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0118] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for measuring and verifying the initial alignment accuracy of a launch vehicle, characterized in that, An initial alignment accuracy measurement and verification device for launch vehicles is provided. This device includes an inertial navigation system (INS), a differential orientation system (DIS), a simulator, and a fixed fixture. The INS includes at least one measurement axis, and the DIS includes at least one set of antennas. Each antenna is arranged parallel to at least one measurement axis. Both the INS and the DIS are connected to the simulator. The INS and antennas are mounted on the fixed fixture, which includes a base frame, a first mounting portion, and at least one pair of second mounting portions. The first mounting portion is adapted to mount the INS, and each pair of second mounting portions is adapted to mount one set of antennas from the DIS. The first mounting portion is located between two second mounting portions, and the center line connecting the two second mounting portions is adapted to be parallel to the measurement axis of the INS during initial measurement. The first mounting portion includes a support base and a turntable. The support base is connected to the turntable and is adapted to mount the INS. The turntable has at least four first adjustment holes, which are connected to the base frame by fasteners. The first adjustment holes are evenly distributed circumferentially around the INS. The initial alignment attitude angle measured by the inertial navigation system and the azimuth angle output by the differential orientation system are obtained; the initial alignment attitude angle represents the attitude angle of the launch vehicle relative to the navigation coordinate system before launch, and the azimuth angle represents the orientation angle of the launch vehicle relative to the Earth fixed coordinate system during the initial alignment process. Based on the initial alignment attitude angle and the azimuth angle, the initial alignment direction angle error is obtained; The initial alignment accuracy of the launch vehicle is adjusted based on the initial alignment direction angle error value. The acquisition of the initial alignment attitude angle measured by the inertial navigation system and the azimuth angle output by the differential orientation system includes: Acquire an initial alignment attitude angle signal set within a set time period. The elements of the initial alignment attitude angle signal set are an array composed of the initial alignment attitude angle measured by the inertial navigation system and a first time, where the first time is the moment when the initial alignment attitude angle is acquired within the set time period. Obtain the set of differential orientation output signals within the set time period. The elements of the differential orientation output signal set are an array composed of the azimuth angle output by the differential orientation and the second time, where the second time is the moment when the azimuth angle output by the differential orientation is obtained within the set time period.

2. The method for measuring and verifying the initial alignment accuracy of a launch vehicle according to claim 1, characterized in that, The method of obtaining the initial alignment direction angle error based on the initial alignment attitude angle and azimuth angle includes: The initial alignment attitude angle signal set is processed based on the second time to obtain the inertial navigation system output signal set at the second time. Based on the set of inertial navigation system output signals and the set of differential orientation system output signals corresponding to the second time, an array of the initial alignment measurement error as a function of time is obtained.

3. The method for measuring and verifying the initial alignment accuracy of a launch vehicle according to claim 2, characterized in that, The process of processing the initial alignment attitude angle signal set based on the second time to obtain the inertial navigation system output signal set at the second time includes: The set of inertial navigation system output signals for the second time is obtained by performing linear interpolation on the initial alignment attitude angle signal set at the second time.

4. The method for measuring and verifying the initial alignment accuracy of a launch vehicle according to claim 3, characterized in that, The array obtained based on the set of inertial group output signals and the set of differential orientation signal corresponding to the second time, which represents the change of the initial alignment measurement error over time, includes: By subtracting the set of inertial navigation system output signals and the set of differential orientation system output signals at the same moment, an array of the initial alignment measurement error as a function of time is obtained.

5. The method for measuring and verifying the initial alignment accuracy of a launch vehicle according to any one of claims 1 to 4, characterized in that, The support base is provided with at least four second adjustment holes, which are arranged in a one-to-one correspondence with the first adjustment holes, and the second adjustment holes are connected to the first adjustment holes by fasteners.

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