A laser attitude measurement and identification method with reflector layout optimization

Abstract

The application provides a laser attitude measurement and identification method with reflector layout optimization, comprising the following steps: installing multiple L-shaped laser corner reflectors, obtaining the measurement distance difference of the multiple laser corner reflectors based on satellite laser ranging, taking the spacing ratio of the multiple laser corner reflectors arranged in a same line as an identity code, defining and calculating the discriminant of the measurement distance difference in sequence, taking the invariant of the discriminant as the matched identity code, determining the target identity and the reflection sequence, determining the one-to-one correspondence between the ranging data and the laser corner reflectors according to the reflection sequence, respectively calculating the included angle between the two baselines and the measurement direction vector, and then combining the coordinates of the station and the target carrier to perform attitude calculation and obtain the attitude of the target carrier. The application realizes the rapid identification of the satellite and the real-time measurement of the complete attitude by the special arrangement of the laser corner reflectors and the satellite laser ranging data.

Description

Technical Field

[0001] This invention belongs to the fields of optical precision measurement, aerospace navigation, optoelectronic measurement and space positioning technology, and specifically relates to a laser attitude measurement and recognition method with optimized reflector layout. Background Technology

[0002] Attitude measurement of space targets can be broadly categorized into two types based on the location of the measurement system: spaceborne active measurement and ground-based passive measurement. Space-based attitude measurement relies on active measurement by spaceborne equipment, such as star sensors, gyroscopes, magnetometers, inertial measurement units, and inter-satellite measurement links. This provides accurate, continuous, and real-time position, velocity, and attitude information, but is susceptible to equipment failures and lifespan limitations. Ground-based attitude measurement, on the other hand, typically establishes a relationship between the ground and space through optical or radar ground stations for passive measurement. Its advantages include lower cost, higher reliability, and less reliance on satellite resources. Attitude measurement based on optical telescopes relies on optical imaging and image processing techniques and is greatly affected by factors such as illumination, day / night cycle, target texture, and resolution limitations. Radar observation (such as ISAR) suffers from drawbacks such as image abstraction, reliance on target motion, and sensitivity to materials. Furthermore, both methods suffer from limitations such as a lack of depth information and difficulties in feature extraction.

[0003] Satellite laser ranging (SLR) solutions largely avoid the aforementioned drawbacks due to their passive nature and active radial distance measurement capabilities. They offer advantages such as lightweight, passive operation, high precision, and long lifespan, achieving millimeter-level ranging accuracy for satellite identification beacons. SLR, a ground-based optical technology, utilizes short-pulse lasers and precise timing devices to measure the round-trip time of a laser pulse emitted from a ground station to a satellite equipped with a laser corner reflector (typically composed of a corner cube prism CCR). This spaceborne passive optical solution is compatible with over 40 SLR sites globally. In low Earth orbit, commercially available CCRs weighing only a few grams can support high-precision satellite ranging at traditional SLR sites. Furthermore, given the passive optics and highly reliable materials of the CCR, it can operate for extended periods even in the event of satellite malfunction. A typical SLR station can easily achieve high-precision ranging of satellites from low Earth orbit to geostationary orbit, with a single CCR achieving millimeter-level ranging accuracy. This high-precision ranging capability often allows researchers to distinguish signals from multiple different CCRs in SLR measurement echoes. The measured data will contain a series of distance differences, which include the carrier's attitude information.

[0004] However, traditional satellite identification beacons cannot calculate the complete attitude of space targets, nor do they have the ability to identify and encode them.

[0005] Current satellite identification beacons can be categorized into active and passive types based on whether they require satellite power. Active methods equip satellites with radio or optical transmitters; identification is achieved when a ground station correctly receives and decodes the satellite's transmitted signals. While active methods can generate identifiers (IDs) covering a large number of satellites, they still have limitations. Extremely low resource optical identifiers (ELROIs), composed of laser diode arrays, require continuous power, increasing the energy consumption burden of small satellites. To enable identification even when the satellite is not operational, an independent power supply needs to be added to the satellite payload, although its operating time remains relatively limited. CubeSat identification tags (CUBITs), based on radio transponders, not only face energy consumption issues but may also cause radio frequency interference. Passive methods, requiring no power and capable of long-term identification even after satellite failure, are more suitable for space traffic management given the current trend towards satellite miniaturization.

[0006] Passive measurement methods primarily rely on unique retroreflective beacons on satellites, with signal transmission, reception, and decoding handled by ground stations. The most common beacon, the Cube Corner Retroreflector (CCR), efficiently returns laser signals transmitted from the ground station along their original path. It boasts advantages such as strong reflectivity, high accuracy, and lightweight design, making it a key payload for satellite laser ranging (SLR) and lunar laser ranging (LLR). However, due to the lack of optimization in the layout and algorithms of CCRs, current technology cannot achieve real-time measurement of the complete attitude. Instead, only partial attitude calculations are possible, or attitude estimation must be performed retrospectively through long-term, extensive observations.

[0007] Furthermore, identification is a primary task in space traffic management, helping to coordinate satellite operations and reduce collision risks. Currently, CubeSats are leading a new trend in satellite launches, with a large number of satellites being launched in clusters within a short period. In such cases, satellite identification can take weeks to months, and up to 20% of the satellites may never be "claimed"—a phenomenon known as "CubeSat confusion." Currently, space target and debris monitoring networks mainly consist of radar and optical telescopes. When satellites with similar shapes and reflective properties are launched in a short period into similar orbits or lose track of each other, the observation network struggles to identify the target.

[0008] These challenges prompted us to develop a solution that combines low-energy satellite identification beacons with high-precision attitude monitoring. Summary of the Invention

[0009] The purpose of this invention is to provide a laser attitude measurement and identification method with optimized reflector layout, so as to achieve rapid satellite identification and real-time complete attitude measurement through the special arrangement of laser corner reflectors and satellite laser ranging data.

[0010] To achieve the above objectives, the present invention provides a laser attitude measurement and recognition method with optimized reflector layout, comprising:

[0011] Step S1: Install multiple L-shaped laser corner reflectors on the target carrier, including at least a first laser corner reflector, a second laser corner reflector, a third laser corner reflector collinear on a first baseline, and a multiplexed first laser corner reflector and a fourth laser corner reflector located on a second baseline. The measurement distance difference between the multiple laser corner reflectors is obtained by the station based on satellite laser ranging. The spacing ratio of the multiple laser corner reflectors collinear on the first baseline is predefined as a unique identification code during installation.

[0012] Step S2: For each station, the measurement distance difference of multiple laser corner reflectors is defined as the first distance difference ΔR in order of reflection distance from near to far. A Second distance difference ΔR B and the third distance difference ΔR C Four discriminant ΔR values ​​were calculated. A / ΔR B ΔR B / ΔR C 、(ΔR A +ΔR B ) / ΔR C ΔR A / (ΔR B +ΔR C Using the invariants in the four discriminant formulas as the matched identification codes, the reflection sequence of the L-shaped laser corner reflector and the identity of the target carrier are determined.

[0013] Step S3: Determine the one-to-one correspondence between the ranging data and the laser corner reflectors based on the reflection sequence, thereby determining the measurement distance difference between the first and second laser corner reflectors and / or the measurement distance difference between the second and third laser corner reflectors and the measurement distance difference between the first and fourth laser corner reflectors, and calculate the angle between the two baselines and the measurement direction vector respectively.

[0014] Step S4: Based on the angle between the two baselines measured by the station and the measurement direction vector, and combined with the coordinates of the station and the target vehicle, the attitude of the target vehicle is calculated; when multiple stations are in common view for measurement, the complete attitude information of the target vehicle is obtained.

[0015] The measurement distance difference of multiple laser corner reflectors is obtained by the station based on satellite laser ranging. Specifically, the station emits a pulsed laser to illuminate the laser corner reflectors, causing the multiple laser corner reflectors to reflect the laser pulses back to the station along the original path. The station uses a photodetector and a timer to measure the reflected signals and obtains the measurement distance difference of the multiple laser corner reflectors based on the reflected signals.

[0016] When m is the identification code and the L-shaped laser corner reflector layout includes only 4 laser corner reflectors, the spacing ratio of the first, second, and third laser corner reflectors collinear on the first baseline is L. 12 / L 23 L 12 L is the distance between the first laser corner reflector and the second laser corner reflector. 23 The distance between the second and third laser corner reflectors; in step S2, at ΔR A / ΔR B When m = , the reflection order is the first, second, third, and fourth laser corner reflectors;

[0017] In ΔR A / (ΔR B +ΔR C When )=m, the reflection order is first, second, fourth, and third laser corner reflectors;

[0018] In (ΔR) A +ΔR B ) / ΔR C When m = , the reflection order is the first, fourth, second, and third laser corner reflectors;

[0019] In ΔR A / ΔR B When the value is 1 / m, the reflection sequence is the third, second, first, and fourth laser corner reflectors;

[0020] In ΔR A / (ΔR B +ΔR C When ) = 1 / m, the reflection order is the third, second, fourth, and first laser corner reflectors;

[0021] In (ΔR) A +ΔR B ) / ΔR C When the value is 1 / m, the reflection order is the third, fourth, second, and first laser corner reflectors;

[0022] In ΔR B / ΔR C When m = , the reflection order is the fourth, first, second, and third laser corner reflectors;

[0023] In ΔR B / ΔR C When the value is 1 / m, the reflection sequence is the fourth, third, second, and first laser corner reflectors.

[0024] The angle between the two baselines and the measurement direction vector is calculated. Specifically, for each baseline, the angle between the baseline vector and the measurement line of sight of the station is calculated by the difference in measurement distance between the laser corner reflectors on the baseline and the length of the baseline.

[0025] When there is only one measuring station, the attitude of the target vehicle is obtained as the attitude angle information of the target vehicle. The attitude angle information of the target vehicle includes the angle θ1 between the vector of the first baseline and the measurement line of sight of the measuring station, and the angle θ2 between the vector of the second baseline and the measurement line of sight of the measuring station.

[0026] When there are at least two stations, including station A and station B, the angle θ between the vector of the first baseline and the line of sight of station A can be obtained. A1 The angle θ between the vector of the second baseline and the line of sight of station A. A2 The angle θ between the vector of the first baseline and the line of sight of station B. B1 The angle θ between the vector of the second baseline and the line of sight of station B. B2 ; Obtain the complete attitude information of the target vehicle, which includes the vector of the first baseline. Vector of the second baseline .

[0027] Vector of the first baseline Vector of the second baseline The following formula can be used to calculate:

[0028] ,

[0029] in, and These are the unit vectors of the line-of-sight directions for station A and station B, respectively. and These are the vectors of the first baseline and the second baseline, respectively; θ A1 Let θ be the angle between the vector of the first baseline and the line of sight of station A. A2 Let θ be the angle between the vector of the second baseline and the line of sight of station A. B1 Let θ be the angle between the vector of the first baseline and the line of sight at station B. B2 The angle between the vector of the second baseline and the line of sight of station B.

[0030] The target carrier includes a satellite, a space station, or space debris, and the laser corner reflector includes a corner prism, a corner prism array, or a Luneburg lens.

[0031] This invention mounts multiple L-shaped laser corner reflectors on a target carrier. The distance difference between these reflectors is obtained by a measuring station using satellite laser ranging. The target's attitude information can then be calculated using the reflector layout and the coordinates of the measuring station and the target. When two measuring stations are simultaneously conducting measurements, the complete target attitude can be obtained. Furthermore, the distance difference information from the specially arranged reflectors can also be used for target identification encoding. Based on the resolvable echoes from multiple reflectors, this application proposes an optimized geometric layout for the reflectors and, for the first time, a complete attitude algorithm with identification capabilities based on reflector laser ranging. This algorithm can compensate for the failure rate of active attitude measurement equipment such as star sensors and the limited lifespan due to limited energy. It achieves attitude measurement and identification using small, lightweight, and passive payloads like reflectors, resulting in low cost and an extremely long operating life. Attached Figure Description

[0032] Figure 1 This is a flowchart of a laser attitude measurement and recognition method based on reflector layout optimization according to an embodiment of the present invention.

[0033] Figure 2A and Figure 2B This is a schematic diagram illustrating how the distance difference along the line of sight in laser ranging is reflected in the time difference of the echo signal. Figure 2A This is a diagram showing the positional relationship between the baseline vector of the laser corner reflector and the measurement line of sight of the station. Figure 2B Is Figure 2A The echo signal diagrams of each laser corner reflector under the positional relationship shown.

[0034] Figures 3A-3C This is a schematic diagram of the measurement principle of bistationary SLR attitude measurement, in which... Figure 3A This is a schematic diagram showing the relative attitudes of the various laser corner reflectors of laser ranging station A, laser ranging station B, and the satellite. Figure 3B and Figure 3C These are the echo signal diagrams of laser ranging station A and laser ranging station B, respectively.

[0035] Figure 4 This is a diagram showing the distribution and incident direction definition of an L-shaped laser corner reflector.

[0036] Figures 5A-5H This is a schematic diagram showing only eight possible reflection sequences determined by the L-shaped layout of the laser corner reflectors. Figures 5A-5H These correspond to sequences 1 through 8, respectively.

[0037] Figure 6 This is a graph showing the variation of the discriminant with the incident azimuth angle. Detailed Implementation

[0038] The embodiments of the present invention are described in detail below. These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments.

[0039] Figure 1 This is a flowchart of a laser attitude measurement and recognition method based on reflector layout optimization according to an embodiment of the present invention. Figure 1 As shown, a laser attitude measurement and recognition method with reflector layout optimization according to the present invention includes the following steps:

[0040] Step S1: Install multiple L-shaped laser corner reflectors (widely using corner cone prisms, i.e., CCRs) on the target carrier, including at least one on the first baseline. The first, second, and third laser corner reflectors, which are collinear, and the one located at the second baseline. The first and fourth laser corner reflectors on the ground are measured by the distance difference between multiple laser corner reflectors obtained by the station based on satellite laser ranging; and will be placed on the first baseline. The spacing ratio L of the collinear first, second, and third laser corner reflectors 12 / L 23 m serves as an identification code;

[0041] The target carrier includes space targets such as satellites, space stations, and space debris that can carry laser corner reflectors. The type of payload (i.e., laser corner reflector) includes various types of laser corner reflectors such as corner prisms, corner prism arrays, and Luneburg lenses.

[0042] The measurement distance difference between multiple laser corner reflectors is obtained by the station based on satellite laser ranging. Specifically, the station emits a pulsed laser to illuminate the laser corner reflectors, causing each reflector to reflect the laser pulse back to the station along its original path. The station uses a photodetector and a timer to measure the reflected signals and obtains the measurement distance difference between the multiple laser corner reflectors based on these signals. The echo time difference of the reflected signals corresponds to the measurement distance difference.

[0043] The laser corner reflectors are arranged in an L-shape, including multiple laser corner reflectors collinear on a first baseline and multiple laser corner reflectors located on a second baseline. The first and second baselines are perpendicular to each other to form an L-shaped arrangement. In this embodiment, as... Figure 3A As shown, the laser corner reflector includes a first baseline. The first, second, and third laser corner reflectors, which are collinear, and the one located at the second baseline. The first laser corner reflector and the fourth laser corner reflector are located on the first baseline and the second baseline, respectively. Therefore, the total number of laser corner reflectors is 4.

[0044] It should be noted that "at least" means that at least three laser corner reflectors are collinearly arranged on the first baseline, and at least two laser corner reflectors are arranged on the second baseline. In this embodiment, the number of laser corner reflectors arranged on the first baseline is three. In other embodiments, the number of laser corner reflectors arranged on the first baseline is four, five, or even more. In some other embodiments, the number of laser corner reflectors arranged on the second baseline is two or more. The most basic feature of the L-shaped layout of the present invention is the two baselines of the L-shape. Increasing the number of laser corner reflectors within the same baseline will further increase the number of coded characters, while also increasing the complexity of recognition. Therefore, in other embodiments, the total number of laser corner reflectors is not necessarily limited to four, but can be more than four. The present invention is only describing this simplest case.

[0045] like Figure 2A and Figure 2B As shown, the distance ratio L between the first laser corner reflector, the second laser corner reflector, and the third laser corner reflector is... 12 / L 23 As a form of identification code m (i.e., m=L) 12 / L 23 ), L 12 L is the distance between the first laser corner reflector and the second laser corner reflector. 23 The distance between the second and third laser corner reflectors is given. Since the distance between the laser corner reflectors is sufficiently large relative to the SLR ranging resolution, obtaining the distance ratio from SLR measurement data is quite easy. This high measurement resolution allows the identification code *m* to distinguish and encode a large number of satellites or other target carriers. Furthermore, the introduction of non-collinearly arranged laser corner reflectors makes it possible to determine the complete attitude of the satellite. In other words, the identification code *m* is a unique value determined when the laser corner reflectors are installed on the target carrier; essentially, it is a quantity that remains unchanged once installed, representing the distance ratio *L*. 12 / L 23 It can be used to identify satellites and also to further assist in measuring their attitude.

[0046] Step S2: As Figures 3A-3C As shown, for each station, the measurement distance difference between multiple laser corner reflectors is defined as the first distance difference ΔR in order of reflection distance from near to far. A Second distance difference ΔR B and the third distance difference ΔR CFour discriminant ΔR values ​​were calculated. A / ΔR B ΔR B / ΔR C 、(ΔR A +ΔR B ) / ΔR C ΔR A / (ΔR B +ΔR C Using the invariants in the four discriminant formulas as the matched identification codes, the reflection sequence of the L-shaped laser corner reflector and the identity of the target carrier are determined.

[0047] In this context, the reflected signals from different laser corner reflectors are not inherently different; the identification of a laser corner reflector relies solely on the spacing relationship. Determining which laser corner reflector a signal originates from in the SLR echo data of only three collinear laser corner reflectors is straightforward. (Refer to...) Figures 2A-2B and Figures 3A-3C For example, suppose the laser corner reflectors on the satellite are installed according to the spacing ratio L 12 / L 23 With the layout set to m=0.5 to obtain the identification code, and the SLR ranging distance measured from near to far having an interval ratio of exactly 2:1, the closest signal must come from the third laser corner reflector. The other two are, in order, the second and first laser corner reflectors. If the SLR ranging distance measured from near to far has an interval ratio of 1:2, then the signal order from near to far is the first laser corner reflector, the second laser corner reflector, and the third laser corner reflector. Therefore, the three collinear laser corner reflectors can only have these two reflection orders.

[0048] However, three laser corner reflectors are insufficient to calculate the vector direction of the complete attitude. Therefore, this invention requires the addition of a fourth, non-collinear laser corner reflector. When the L-shaped laser corner reflector configuration includes only four reflectors, the different reflection sequences of the L-shaped laser corner reflectors will each correspond to a unique discriminant value, as shown in Table 1. Figures 2A-2B , Figures 3A-3C and Figure 6 As shown. Figure 2A In this context, θ is the angle between the baseline vector and the direction of the measurement line of sight at the station. The direction of the measurement line of sight at the station. The vector of the baseline, Figure 3A middle, The vector of the first baseline. The vector of the second baseline, The vector of the third baseline perpendicular to the first and second baselines. and These are the unit vectors representing the line-of-sight directions of stations A and B, respectively. (See Table 1.) Figures 2A-2B , Figures 3A-3C and Figure 6 As shown, the value of the discriminant matching the identification code m is fixed and does not change with the attitude of the target carrier. Therefore, this invention can measure the target without knowing the identification code. Based on the measurement data, four discriminants can be obtained. From these four discriminants, invariants can be obtained (only one of the four discriminants will have an invariant; the other three change rapidly with the ranging process). The invariant itself serves as the matched identification code m or 1 / m. This determines the identity of the target carrier and obtains the reflection sequence of the L-shaped laser corner reflector, allowing for further attitude calculation in subsequent steps.

[0049] Figure 4 This is a diagram showing the distribution and incident direction definition of an L-shaped laser corner reflector layout. According to... Figure 4 As shown in the incident direction, the reflection sequence of the laser corner reflector is 3→2→4→1. Figures 5A-5H This is a schematic diagram showing only eight possible reflection sequences determined by the L-shaped layout of the laser corner reflectors.

[0050] Figure 6 The discriminant varies with the incident azimuth angle θ0 (see coordinate definition). Figure 4 (Set the identification code m=0.5, and combine it with Table 1 to determine the measurement sequence as the azimuth angle changes from 0 to 360°.) Figures 5A-5H The sequence 5, 6, 8, 7, 3, 2, 1, and 4 uniquely determines the reflection order of the laser corner reflectors. The reflection order of the L-shaped laser corner reflectors includes the laser corner reflectors corresponding to each distance point; that is, each distance point corresponds to either the first, second, third, or fourth laser corner reflector. The measured distance difference is the projection of the distance L of the laser corner reflector onto the distance measurement line-of-sight vector.

[0051] Table 1: Four identification code discrimination formulas corresponding to different reflection orders of laser corner reflectors

[0052]

[0053] Step S3: Determine the one-to-one correspondence between the ranging data and the laser corner reflectors based on the reflection sequence, thereby determining the measurement distance difference ΔR between the first and second laser corner reflectors. 12 And / or the measurement distance difference ΔR between the second and third laser corner reflectors 23 And the measurement distance difference ΔR between the first laser corner reflector and the fourth laser corner reflector.14 The angles between the two baselines and the measurement direction vector are calculated respectively.

[0054] The calculation of the angle between the two baselines and the measurement direction vector includes:

[0055] For each baseline, the angle between the baseline vector and the measurement line of sight of the station is calculated by the difference in measurement distance between the laser corner reflectors on the baseline and the length of the baseline.

[0056] The angle θ between the baseline vector and the line of sight of the station satisfies the following formula:

[0057] cosθ=ΔR / L (1)

[0058] Where ΔR is the measurement distance difference of the laser corner reflectors on the baseline, and L is the length of the baseline.

[0059] In other words, for the first baseline, the angle θ1 between the vector of the first baseline and the direction of the measurement line of sight at the station is:

[0060]

[0061] Where, ΔR 12 ΔR represents the difference in measurement distance between the first laser corner reflector and the second laser corner reflector. 23 L represents the measurement distance difference of the third laser corner reflector. 12 L is the distance between the first laser corner reflector and the second laser corner reflector. 23 The distance between the second and third laser corner reflectors.

[0062] For the second baseline, the angle θ2 between the vector of the second baseline and the direction of the measurement line of sight at the station is:

[0063]

[0064] Where, ΔR 14 L represents the difference in measured distance between the first and fourth laser corner reflectors. 14 The distance between the first laser corner reflector and the fourth laser corner reflector.

[0065] Step S4: Based on the angle between the two baselines measured by the station and the measurement direction vector, and combined with the coordinates of the station and the target vehicle, the attitude of the target vehicle is calculated; when multiple stations are in common view for measurement, the complete attitude information of the target vehicle is obtained.

[0066] When there is only one measuring station, the attitude of the target vehicle is obtained as the attitude angle information of the target vehicle. The attitude angle information of the target vehicle includes the angle θ1 between the vector of the first baseline and the measurement line of sight of the measuring station, and the angle θ2 between the vector of the second baseline and the measurement line of sight of the measuring station.

[0067] When the number of measuring stations is at least two, that is, when multiple measuring stations are in common view, the complete attitude information of the target carrier is obtained, and the attitude of the target carrier obtained is the complete attitude information of the target carrier.

[0068] Specifically, when the number of stations is at least two (i.e., including station A and station B), the angle θ between the vector of the first baseline and the line of sight of station A can be obtained. A1 The angle θ between the vector of the second baseline and the line of sight of station A. A2 The angle θ between the vector of the first baseline and the line of sight of station B. B1 The angle θ between the vector of the second baseline and the line of sight of station B. B2 Therefore, the vector of the first baseline Vector of the second baseline (i.e., the laser corner reflector arrangement vector) can be completely determined in space, yielding complete attitude information of the target carrier. The complete attitude information of the target carrier includes the vector of the first baseline. Vector of the second baseline Among them, the vector of the first baseline Vector of the second baseline It is the quantity to be measured, which can be represented as (x1, y1, z1) and (x2, y2, z2), in fact, solving the attitude is to find these 6 unknowns.

[0069] Vector of the first baseline Vector of the second baseline The following formula (2) is used to calculate:

[0070] (2)

[0071] in, and These are the unit vectors of the line-of-sight directions of station A and station B, respectively, which can be obtained from the station coordinates and satellite orbit data; and These are the vectors of the first baseline and the second baseline, respectively; θ A1 Let θ be the angle between the vector of the first baseline and the line of sight of station A. A2 Let θ be the angle between the vector of the second baseline and the line of sight of station A. B1Let θ be the angle between the vector of the first baseline and the line of sight at station B. B2 The angle between the vector of the second baseline and the line of sight of station B.

[0072] Therefore, the complete attitude information of the target carrier can be determined.

[0073] The formula above can be refined to obtain θ. A1 θ A2 θ B1 θ B2 The formula:

[0074]

[0075] Among them, the subscripts containing A are obtained by measurement from station A, and the subscripts containing B are obtained by measurement from station B.

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. That is, all simple and equivalent changes and modifications made based on the claims and description of this invention fall within the protection scope of the claims of this patent. All aspects not described in detail in this invention are conventional technical content.

Claims

1. A laser attitude measurement and recognition method with optimized reflector layout, characterized in that, include: Step S1: Install multiple L-shaped laser corner reflectors on the target carrier, including at least a first laser corner reflector, a second laser corner reflector, a third laser corner reflector collinear on a first baseline, and a multiplexed first laser corner reflector and a fourth laser corner reflector located on a second baseline. The measurement distance difference between the multiple laser corner reflectors is obtained by the station based on satellite laser ranging. The spacing ratio of the multiple laser corner reflectors collinear on the first baseline is predefined as a unique identification code during installation. Step S2: For each station, the measurement distance difference of multiple laser corner reflectors is defined as the first distance difference ΔR in order of reflection distance from near to far. A Second distance difference ΔR B and the third distance difference ΔR C Four discriminant ΔR values ​​were calculated. A / ΔR B ΔR B / ΔR C 、(ΔR A +ΔR B ) / ΔR C ΔR A / (ΔR B +ΔR C Using the invariants in the four discriminant formulas as the matched identification codes, the reflection sequence of the L-shaped laser corner reflector and the identity of the target carrier are determined. Step S3: Determine the one-to-one correspondence between the ranging data and the laser corner reflectors based on the reflection sequence, thereby determining the measurement distance difference between the first and second laser corner reflectors and / or the measurement distance difference between the second and third laser corner reflectors and the measurement distance difference between the first and fourth laser corner reflectors, and calculate the angle between the two baselines and the measurement direction vector respectively. Step S4: Based on the angle between the two baselines measured by the station and the measurement direction vector, and combined with the coordinates of the station and the target vehicle, the attitude of the target vehicle is calculated; when multiple stations are in common view for measurement, the complete attitude information of the target vehicle is obtained.

2. The laser attitude measurement and recognition method for reflector layout optimization according to claim 1, characterized in that, The measurement distance difference of multiple laser corner reflectors is obtained by the station based on satellite laser ranging. Specifically, the station emits a pulsed laser to illuminate the laser corner reflectors, causing the multiple laser corner reflectors to reflect the laser pulses back to the station along the original path. The station uses a photodetector and a timer to measure the reflected signals and obtains the measurement distance difference of the multiple laser corner reflectors based on the reflected signals.

3. The laser attitude measurement and recognition method for reflector layout optimization according to claim 1, characterized in that, When m is the identification code and the L-shaped laser corner reflector layout includes only 4 laser corner reflectors, the spacing ratio of the first, second, and third laser corner reflectors collinear on the first baseline is L. 12 / L 23 L 12 L is the distance between the first laser corner reflector and the second laser corner reflector. 23 The distance between the second and third laser corner reflectors; in step S2, at ΔR A / ΔR B When m = , the reflection order is the first, second, third, and fourth laser corner reflectors; In ΔR A / (ΔR B +ΔR C When )=m, the reflection order is first, second, fourth, and third laser corner reflectors; In (ΔR) A +ΔR B ) / ΔR C When m = , the reflection order is the first, fourth, second, and third laser corner reflectors; In ΔR A / ΔR B When the value is 1 / m, the reflection sequence is the third, second, first, and fourth laser corner reflectors; In ΔR A / (ΔR B +ΔR C When ) = 1 / m, the reflection order is the third, second, fourth, and first laser corner reflectors; In (ΔR) A +ΔR B ) / ΔR C When the value is 1 / m, the reflection order is the third, fourth, second, and first laser corner reflectors; In ΔR B / ΔR C When m = , the reflection order is the fourth, first, second, and third laser corner reflectors; In ΔR B / ΔR C When the value is 1 / m, the reflection sequence is the fourth, third, second, and first laser corner reflectors.

4. The laser attitude measurement and recognition method with optimized reflector layout according to claim 1, characterized in that, The angle between the two baselines and the measurement direction vector is calculated. Specifically, for each baseline, the angle between the baseline vector and the measurement line of sight of the station is calculated by the difference in measurement distance between the laser corner reflectors on the baseline and the length of the baseline.

5. The laser attitude measurement and recognition method for reflector layout optimization according to claim 1, characterized in that, When there is only one measuring station, the attitude of the target vehicle is obtained as the attitude angle information of the target vehicle. The attitude angle information of the target vehicle includes the angle θ1 between the vector of the first baseline and the measurement line of sight of the measuring station, and the angle θ2 between the vector of the second baseline and the measurement line of sight of the measuring station.

6. The laser attitude measurement and recognition method for reflector layout optimization according to claim 1, characterized in that, When there are at least two stations, including station A and station B, the angle θ between the vector of the first baseline and the line of sight of station A can be obtained. A1 The angle θ between the vector of the second baseline and the line of sight of station A. A2 The angle θ between the vector of the first baseline and the line of sight of station B. B1 The angle θ between the vector of the second baseline and the line of sight of station B. B2 ; Obtain the complete attitude information of the target vehicle, which includes the vector of the first baseline. Vector of the second baseline .

7. The laser attitude measurement and recognition method for reflector layout optimization according to claim 6, characterized in that, Vector of the first baseline Vector of the second baseline The following formula can be used to calculate: ， in, and These are the unit vectors of the line-of-sight directions for station A and station B, respectively. and These are the vectors of the first baseline and the second baseline, respectively; θ A1 Let θ be the angle between the vector of the first baseline and the line of sight of station A. A2 Let θ be the angle between the vector of the second baseline and the line of sight of station A. B1 Let θ be the angle between the vector of the first baseline and the line of sight at station B. B2 The angle between the vector of the second baseline and the line of sight of station B.

8. The laser attitude measurement and recognition method for reflector layout optimization according to claim 1, characterized in that, The target carrier includes a satellite, a space station, or space debris, and the laser corner reflector includes a corner prism, a corner prism array, or a Luneburg lens.

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