Intersatellite relative position measurement device and method based on laser beam tracking corner reflector

Abstract

This invention discloses an inter-satellite relative position measurement device and method based on a laser beam tracking corner reflector, belonging to the field of inter-satellite measurement technology. The measurement device includes a main unit and a laser corner reflector, respectively mounted on two satellites whose relative positions are to be measured. It fully utilizes the high-precision ranging capabilities of laser and the high-precision angle measurement capabilities of star sensors, combining the two while maintaining a clear reference point, achieving millimeter-level and sub-millimeter-level relative measurement accuracy. This invention can be used for high-precision relative measurements between satellites and is also applicable to various engineering scenarios requiring real-time or post-hoc high-precision relative measurements.

Description

Technical Field

[0001] This invention relates to an inter-satellite relative position measurement device and method based on a laser beam tracking corner reflector, and more particularly to an device and method for achieving high-precision inter-satellite relative position measurement based on a laser beam tracking corner reflector, belonging to the field of inter-satellite measurement technology. Background Technology

[0002] With the continuous expansion of high-precision satellite formation and large-scale constellation applications in orbit, complex applications have placed higher demands on the relative measurement technology between satellites in formation. Especially with the need for millimeter-level and sub-millimeter-level accuracy in relative measurements, traditional methods relying on microwave ranging, microwave radar ranging and angle measurement, and lidar ranging and angle measurement to obtain inter-satellite relative positions have encountered technical bottlenecks. On the one hand, ranging accuracy is limited; microwave ranging methods are constrained by time detection accuracy and microwave wavelength, resulting in low precision. On the other hand, the accuracy of motion pointing and angle measurement is limited. Traditional pointing control based on mechanical bearings and angle measurement technology based on photoelectric encoders already face significant challenges in achieving arcsecond-level accuracy. Furthermore, in the range of hundreds of meters to kilometers, arcsecond-level angle measurement errors can lead to centimeter-level position measurement errors (a 10″ angle measurement error corresponds to approximately 1 cm of position error at a distance of 200 meters).

[0003] Therefore, in order to achieve relative measurement accuracy at the millimeter or even sub-millimeter level, it is necessary to change the existing measurement system and measurement methods. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose an inter-satellite relative position measurement device and method based on a laser beam tracking corner reflector, so as to achieve relative measurement accuracy at the millimeter level or even the sub-millimeter level.

[0005] The technical solution of this invention is:

[0006] An inter-satellite relative position measurement device based on a laser beam tracking corner reflector includes a main measuring instrument and a laser corner reflector, which are respectively installed on two satellites whose relative positions are to be measured;

[0007] The main unit of the measuring instrument includes a composite tracking platform, a laser measuring instrument, and a star sensor;

[0008] The composite tracking platform drives the laser measuring instrument and the star sensor to achieve the search and tracking control of space targets;

[0009] The laser measuring instrument and the star sensor are mounted on the composite tracking platform; the laser measuring instrument is equipped with a laser emission and reception module, and obtains the distance of the laser angle reflection device and the deviation angle of the laser beam main axis relative to the laser angle reflection device by measuring the laser emission and reception.

[0010] The star sensor is fixedly connected to the laser measuring instrument. During the process of the laser beam tracking the laser angle reflection device, the star sensor moves accordingly to obtain the spatial orientation of the laser ranging moment in the inertial frame.

[0011] Furthermore, the laser corner reflector includes a corner reflector and a one-dimensional rotation mechanism;

[0012] The angular reflector center point P is located on the rotation axis of the one-dimensional rotation mechanism;

[0013] A one-dimensional rotation mechanism drives the corner reflector to rotate, and based on the coarse relative position information, the corner reflector faces the main unit of the measuring instrument.

[0014] Furthermore, the corner reflector employs a corner prism.

[0015] Furthermore, the composite tracking platform includes a micro-pointing control platform and a two-dimensional rotation mechanism; the micro-pointing control platform is mounted on the two-dimensional rotation mechanism and performs attitude pointing precision tracking based on the deviation angle of the laser beam main axis relative to the laser angle reflection device measured by the laser measuring instrument.

[0016] Furthermore, the star sensor is fixedly connected to the transmitting antenna of the laser measuring instrument.

[0017] Methods for measuring inter-satellite relative positions using an inter-satellite relative position measurement device include:

[0018] S1: The main measuring instrument and the laser corner reflector are respectively deployed on the two satellites whose relative positions are to be measured. The reference point for the installation of the main measuring instrument is O. s The angular reflection center point of the laser corner reflector is P;

[0019] S2: The two-dimensional rotation mechanism that drives the main unit of the measuring instrument, so that the optical axis of the laser measuring instrument's optical antenna is coarsely directed towards the corner reflector;

[0020] S3: Turn on the laser on the laser measuring instrument so that the laser beam can return to the main unit of the measuring instrument after passing through the corner reflector;

[0021] S4: Through the attitude pointing and fine tracking control of the micro-pointing control platform, the center of the laser beam is pointed to and tracked to the angular reflection center, so that the energy value of the returned laser beam reaches the maximum.

[0022] S5: Read the laser ranging result of the laser measuring instrument at the current moment. c P, and record the quaternion q1 of the star sensor's inertial attitude; where the laser measuring instrument's measurement reference point is O. c ;

[0023] S6: Calculate the inertial attitude pointing of the composite tracking platform at the measurement moment using a star sensor to obtain the O in inertial space. c P vector;

[0024] S7: Based on the inertial orientation and rotation angle of the laser measuring instrument, obtain the inertial space vector O. s O c By adding vectors, the precise relative position vector O from the laser measuring instrument reference point to the angular reflection center can be calculated. s P, obtains the precise relative position information between the reference points arranged on the two stars.

[0025] Further, in step S7, the precise relative position vector O from the laser measuring instrument reference point to the angular reflection center is calculated. s P, the specific method is as follows:

[0026]

[0027] Where ρ1 is the equivalent distance from the center of the composite tracking platform to the installation reference point; ρ2 is the relative distance from the laser reference point to the corner reflector reference point measured by the laser rangefinder; A(q) is the operation of converting the quaternion into an attitude transformation matrix; q1 is the inertial pointing quaternion of the laser measuring instrument when the laser points to the opposite center; q2 is the inertial pointing quaternion of the laser measuring instrument when the rotation angle is zero; φ s θ s Install inertial pointing and azimuth and pitch angles for the measuring instrument.

[0028] Further, in step S2, an optical beacon is arranged around the corner reflector, and an optical camera is arranged at the laser measuring instrument end. Through searching and coarse acquisition, the optical axis direction of the measuring instrument's optical antenna is coarsely pointed towards the corner reflector.

[0029] Further, in step S3, the laser on the laser measuring instrument is turned on so that the laser beam can return to the main unit of the measuring instrument after passing through the corner reflector. While completing the ranging function, the two-dimensional photoelectric position detector installed inside the laser measuring instrument is used to measure the shape and energy of the returned laser spot. By inverting the beam cutting situation, the azimuth information of the laser beam deviating from the angular reflection center is determined.

[0030] Furthermore, in step S3, based on the azimuth information of the laser beam deviation angle from the center, the micro-pointing control platform performs attitude pointing fine tracking control, driving the pointing adjustment and tracking of the micro-pointing platform.

[0031] The advantages of the present invention compared with the prior art are:

[0032] (1) This invention uses a high-precision star sensor at the 50 milliarcsecond level to convert high-precision angle measurement into inertial attitude measurement, which greatly improves the accuracy of angle measurement.

[0033] (2) The present invention uses a two-dimensional photoelectric position detector to measure the pointing deviation of the laser beam, so that the ranging laser beam can be aligned with the target corner reflector, thereby achieving precise alignment with the relative measurement reference point.

[0034] (3) This invention makes comprehensive use of a high-precision star sensor and a high-precision pointing control mechanism. The reference point for relative measurement is accurately known and the relative measurement relationship is clear. When the star sensor and the composite pointing control mechanism achieve sub-arcsecond accuracy, millimeter-level relative position measurement accuracy can be achieved within a kilometer range. Attached Figure Description

[0035] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0036] Figure 1 This is a schematic diagram of an inter-satellite relative measurement device arranged on two satellites according to an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of a laser tracking measuring instrument according to an embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of the 2D-PSD position detection in embodiment 2 of the present invention. Detailed Implementation

[0039] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0040] To address the need for high-precision relative measurements between satellites and the existing problems in current relative measurements, this invention proposes an inter-satellite relative position measurement device and method based on a laser beam tracking corner reflector. It fully utilizes the characteristics of high-precision laser ranging and high-precision angle measurement by star sensors, combining the two, while ensuring a clear measurement reference point, and can achieve relative measurement accuracy at the millimeter and sub-millimeter levels.

[0041] The measurement method specifically includes the following steps:

[0042] S1: Deploy the main measuring instrument on the two satellites at the relative positions to be measured (installation reference point O) s ) and laser corner reflector (corner reflection center point P), such as Figure 1 As shown, the main measuring instrument includes a two-dimensional rotation mechanism, a micro-pointing control platform mounted on the rotation mechanism, a laser measuring instrument and a star sensor mounted on the platform; the laser corner reflector includes a corner reflector prism and a one-dimensional rotation mechanism that drives its rotation, and by installation, it is ensured that point P is located on the rotation axis of the one-dimensional mechanism.

[0043] Measuring instrument main unit such as Figure 2 As shown: 1) It is equipped with a two-dimensional rotation mechanism and precise pointing control function, which can realize the search and tracking control of spatial targets through two-dimensional drive; 2) It is equipped with a laser emission and reception module, which can obtain the distance of the target angular reflection and the deviation angle of the laser beam main axis relative to the angular reflection center through laser emission and reception measurement; 3) The star sensor is fixedly connected to the laser emission and reception module. During the process of the laser beam tracking the angular reflection center, the star sensor can move with it, so as to obtain its spatial pointing in the inertial frame at the moment of laser ranging.

[0044] Laser corner reflector: 1) It is equipped with a one-dimensional rotation mechanism, which can make the corner reflector mounted on it face the laser measuring instrument host as much as possible according to the coarse relative position information; 2) It is equipped with a laser corner reflector, and the center P of the laser corner reflector is located on the rotation axis of the one-dimensional mechanism, which makes the position of P relative to the star not change during the rotation of the one-dimensional rotation mechanism.

[0045] S2: The two-dimensional rotation mechanism of the driving measuring instrument host, through search and coarse capture, makes the optical axis of the measuring instrument's optical antenna coarsely point to the corner reflector. Specifically, optical beacons can be arranged around the corner reflector, and an optical camera can be arranged at the measuring instrument end to achieve this function.

[0046] S3: Turn on the laser on the measuring instrument main unit (measurement reference point O) c This allows the laser beam to return to the main unit of the measuring instrument after passing through the corner reflector; this function is the laser ranging function. The difference is that, while performing the ranging function, a two-dimensional photoelectric position detector (2D-PSD) is also needed to measure the shape and energy of the returned laser spot, such as... Figure 3 As shown, the azimuth information of the laser beam's deviation angle from the anti-center is determined by inverting the beam cutting situation.

[0047] S4: Through the attitude pointing precision tracking control of the micro-pointing control platform, the laser beam center is pointed and tracked to the angular reflection center, thereby maximizing the energy value of the returning laser beam. This precise pointing control requires the azimuth information acquired in S3 to drive the pointing adjustment and tracking of the micro-pointing platform.

[0048] S5: Read the laser ranging result at this time. c P, and record the inertial attitude (azimuth angle) of the high-precision star sensor fixed to the main unit of the measuring instrument. Pitch angle θ);

[0049] S6: The inertial attitude orientation of the tracking mechanism at the measurement moment is calculated by a high-precision star sensor fixedly connected to the laser transmitting antenna, thereby obtaining the O in inertial space. c P vector;

[0050] S7: The inertial orientation of the measuring instrument and the angle of rotation of the measuring instrument (azimuth angle) Pitch angle θ s ), thus obtaining the O in inertial space s O c Vectors are used to calculate the precise relative position O from the reference point of the measuring instrument to the center of the angular reflection by adding vectors. s The P vector is used to obtain the precise relative position information between the reference points arranged on the two stars.

[0051] The specific calculation method for the precise relative position information between reference points on the two stars is as follows: O in inertial space s Vector P. To obtain this vector, a star sensor needs to be installed on the platform fixed to the coordinate system of the measuring instrument, thus obtaining the inertial pointing quaternion q2 when the measuring instrument's rotation angle is zero. By adding the vectors, the precise relative position O from the measuring instrument's reference point to the angular reflection center can be calculated. s P vector.

[0052]

[0053] Where: ρ1 is the equivalent distance from the center of the rotating mechanism to the installation reference point, obtained from the actual measured mechanical dimensions; ρ2 is the relative distance from the laser reference point to the corner reflector reference point measured by the laser rangefinder; A(q) is the operation of converting the quaternion into an attitude transformation matrix; q1 is the inertial pointing quaternion of the measuring instrument when the laser is pointing towards the laser angle opposite to the center; q2 is the inertial pointing quaternion when the measuring instrument's rotation angle is zero.

[0054] The device and method proposed in this invention have a clear principle and a well-defined process. They make full use of high-precision laser ranging and high-precision star sensor angle measurement, combining the two. At the same time, the measurement reference point is clear, which has good engineering feasibility. It can be used for high-precision relative measurement between satellites, and is also applicable to various engineering and technical scenarios that require real-time or post-event high-precision relative measurement.

[0055] The embodiments described above are merely preferred embodiments of the present invention. Ordinary variations and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for measuring inter-satellite relative positions, characterized in that, include: S1: The main measuring instrument and the laser corner reflector are respectively deployed on the two satellites whose relative positions are to be measured. The reference point for the installation of the main measuring instrument is O. s The angular reflection center point of the laser corner reflector is P; S2: Arrange optical beacons around the corner reflector and arrange an optical camera at the laser measuring instrument end to drive the two-dimensional rotation mechanism of the measuring instrument host. Through search and coarse capture, make the optical axis direction of the laser measuring instrument optical antenna coarsely point to the corner reflector. S3: Turn on the laser on the laser measuring instrument so that the laser beam can return to the main unit of the measuring instrument after passing through the corner reflector; while completing the ranging function, use the two-dimensional photoelectric position detector installed inside the laser measuring instrument to measure the shape and energy of the returned laser spot. By inverting the beam cutting situation, determine the azimuth information of the laser beam deviating from the angular reflection center; based on the azimuth information of the laser beam deviating from the angular reflection center, the micro-pointing control platform performs attitude pointing fine tracking control, driving the pointing adjustment and tracking of the micro-pointing platform; S4: Through the attitude pointing and fine tracking control of the micro-pointing control platform, the center of the laser beam is pointed to and tracked to the center of the angular reflection, so that the energy value of the returned laser beam reaches the maximum. S5: Read the laser ranging result of the laser measuring instrument at the current moment. c P, and record the quaternion q1 of the star sensor's inertial attitude; where the laser measuring instrument's measurement reference point is O. c ; S6: Calculate the inertial attitude pointing of the composite tracking platform at the measurement time using a star sensor to obtain the inertial space. Vector; S7: Based on the inertial orientation and rotation angle of the laser measuring instrument, obtain the inertial space vector. By adding vectors, the precise relative position vector from the laser measuring instrument reference point to the center of the angular reflection can be calculated. We obtain the precise relative position information between the reference points positioned on the two stars: Where ρ1 is the equivalent distance from the center of the composite tracking platform to the installation reference point; ρ2 is the relative distance from the laser reference point to the corner reflector reference point measured by the laser rangefinder; A(q) is the operation of converting the quaternion into an attitude transformation matrix; q1 is the inertial pointing quaternion of the laser measuring instrument when the laser points to the opposite center; q2 is the inertial pointing quaternion of the laser measuring instrument when the rotation angle is zero; φ s θ s Install inertial pointing and azimuth and pitch angles for the measuring instrument.

2. The method for measuring inter-satellite relative positions according to claim 1, characterized in that, The main measuring instrument and the laser corner reflector are respectively mounted on two satellites at relative positions to be measured; The main unit of the measuring instrument includes a composite tracking platform, a laser measuring instrument, and a star sensor; The composite tracking platform drives the laser measuring instrument and the star sensor to achieve the search and tracking control of space targets; The laser measuring instrument and the star sensor are mounted on the composite tracking platform; the laser measuring instrument is equipped with a laser emission and reception module, and obtains the distance of the laser angle reflection device and the deviation angle of the laser beam main axis relative to the laser angle reflection device by measuring the laser emission and reception. The star sensor is fixedly connected to the laser measuring instrument. During the process of the laser beam tracking the laser angle reflection device, the star sensor moves accordingly to obtain the spatial orientation of the laser ranging moment in the inertial frame.

3. The method for measuring inter-satellite relative positions according to claim 2, characterized in that, The laser corner reflector includes a corner reflector and a one-dimensional rotation mechanism; The angular reflector's center point P is located on the axis of the one-dimensional rotating mechanism; A one-dimensional rotation mechanism drives the corner reflector to rotate, and based on the coarse relative position information, the corner reflector faces the main unit of the measuring instrument.

4. The method for measuring inter-satellite relative positions according to claim 3, characterized in that, The corner reflector is a corner prism.

5. The method for measuring inter-satellite relative positions according to claim 2, characterized in that, The composite tracking platform includes a micro-pointing control platform and a two-dimensional rotation mechanism; the micro-pointing control platform is installed on the two-dimensional rotation mechanism and performs attitude pointing precision tracking based on the deviation angle of the laser beam main axis relative to the laser angle reflection device measured by the laser measuring instrument.

6. The method for measuring inter-satellite relative positions according to claim 2, characterized in that, The star sensor is fixedly connected to the transmitting antenna of the laser measuring instrument.

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