Satellite-borne radar antenna baseline real-time six-degree-of-freedom measuring device and measuring method

Abstract

The invention relates to a satellite-borne radar antenna baseline real-time six-degree-of-freedom measurement device and a measurement method. The satellite-borne radar antenna baseline real-time six-degree-of-freedom measurement device comprises a distance measurement assembly, a rotation angle measurement assembly and a displacement measurement assembly, one side of a satellite is provided with an extension arm capable of extending or retracting, one side of one end, away from the satellite, of the extension arm is provided with an extension antenna, and the distance measurement assembly is installed on one side of the satellite and the extension antenna. The displacement measuring assembly is arranged on one side of the satellite and on the extending antenna and used for measuring the rotation angle of the extending antenna surrounding the satellite and the rotation angle of the extending antenna rotating around the satellite, and the displacement measuring assembly is arranged on one side of the satellite and on the extending antenna and used for measuring the displacement change of the extending antenna in the antenna base line direction. The angle of rotation of the extension antenna around the axis of the extension arm is measured. The device has the advantages of being reasonable in structural design, and capable of measuring the position and the rotation angle of the extending antenna relative to the fixed antenna in real time, and further correcting a radar baseline in real time to ensure the on-orbit working performance of the radar.

Description

Technical Field

[0001] The invention relates to the field of satellite-borne radar antennas, and in particular to a satellite-borne radar antenna baseline real-time six-degree-of-freedom measurement device and a measurement method. Background Art

[0002] Spaceborne InSAR radars usually have two (or more) antennas working simultaneously to perform interferometric measurements of the ground. The working principle of the radar requires that the length of the antenna's phase center line (i.e., baseline) and its on-orbit attitude remain stable. Usually, one antenna is fixed to the satellite, and the other antenna is extended through an extension arm structure to ensure the baseline length requirement. The extension arm is long and is affected by the mechanical force environment and thermal environment when working on-orbit, resulting in continuous dynamic deformation. This deformation will cause changes in the length and attitude of the baseline.

[0003] Therefore, it is necessary to use a real-time six-degree-of-freedom measurement device to measure the position and angle of the extended antenna relative to the fixed antenna, and then make real-time corrections to the radar baseline to ensure the radar's on-orbit performance. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a real-time six-degree-of-freedom measurement device and a measurement method for a satellite-borne radar antenna baseline, which effectively overcomes the defects of the prior art.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] A real-time six-degree-of-freedom measurement device for a satellite-borne radar antenna baseline comprises a distance measuring component, an angle measuring component and a displacement measuring component. A extending arm that can be extended or retracted is provided on one side of the satellite, and the extending antenna is installed on one side of the extending arm away from the satellite. The distance measuring component is installed on one side of the satellite and on the extending antenna, and is used to measure the displacement change of the extending antenna along the direction of its antenna baseline. The angle measuring component is installed on one side of the satellite and on the extending antenna, and is used to measure the angle of rotation of the extending antenna around the satellite and the angle of rotation around itself. The displacement measuring component is installed on one side of the satellite and on the extending antenna, and is used to measure the angle of rotation of the extending antenna around the axis of the extending arm.

[0007] Based on the above technical solution, the present invention can also be improved as follows.

[0008] Furthermore, the distance measuring component includes a laser rangefinder and a plane reflector. The laser rangefinder is installed on the side of the satellite close to the extended antenna, and the plane reflector is installed on the side of the extended antenna close to the satellite. The laser rangefinder and the plane reflector are distributed at both ends of the antenna baseline.

[0009] Furthermore, the above-mentioned angle measurement component includes a laser collimation goniometer and a first reflecting prism. The above-mentioned angle measurement component is provided with at least one group. The above-mentioned laser collimation goniometer is installed on the side of the satellite close to the extended antenna and close to the above-mentioned laser rangefinder. The above-mentioned first reflecting prism is installed on the side of the extended antenna close to the satellite and close to the above-mentioned plane reflecting mirror.

[0010] Furthermore, the above-mentioned rotation angle measurement component is provided in a group.

[0011] Furthermore, the above-mentioned displacement measuring component includes a laser displacement measuring instrument and a second reflecting prism. The above-mentioned displacement measuring component is provided with N groups, and N is an even number. The N groups of the above-mentioned second reflecting prisms are respectively installed on the side of the extended antenna close to the satellite, and are symmetrically distributed on both sides of the antenna baseline. The N groups of the above-mentioned laser displacement measuring instruments are respectively installed on the side of the above-mentioned satellite close to the extended antenna, and are symmetrically distributed on both sides of the antenna baseline, and the N groups of the above-mentioned laser displacement measuring instruments and the N groups of the above-mentioned second reflecting prisms are distributed one by one.

[0012] Furthermore, the above-mentioned displacement measurement components are provided in two groups.

[0013] Furthermore, the laser rangefinder, the laser collimation goniometer and the two groups of laser displacement measuring instruments are distributed on the same straight line.

[0014] Furthermore, the plane reflector, the first reflective prism and the two groups of second reflective prisms are distributed on the same straight line and arranged along a side edge of the extended antenna.

[0015] The beneficial effects are: the structural design is reasonable, and the position and rotation angle of the extended antenna relative to the fixed antenna can be measured in real time, and the radar baseline can be corrected in real time to ensure the radar's on-orbit working performance.

[0016] A method for real-time six-degree-of-freedom measurement of a satellite-borne radar antenna baseline is also provided, comprising the following steps:

[0017] Step 1: In the initial state, the laser rangefinder faces the plane reflector along the antenna baseline direction, the laser collimation goniometer faces the first reflective prism, and the two groups of laser displacement measuring instruments face the two groups of second reflective prisms respectively. With the satellite center as the origin, the antenna baseline direction is set as the Y direction, the extension direction of the extended antenna is the X axis, and the direction perpendicular to the X axis and the Y axis is the Z axis, and a three-dimensional space coordinate system is established;

[0018] Step 2: measuring the distance D between the laser paths respectively formed between the two sets of laser displacement measuring instruments and the corresponding two sets of second reflecting prisms in the initial state;

[0019] Step 3: Use a laser rangefinder to measure the displacement ΔY of the extended antenna on the Y axis in real time, use a laser collimation goniometer to measure the rotation angles θx and θz of the extended antenna around the X axis and around the Z axis in real time, and use two sets of laser displacement measuring instruments to measure the displacements X1, X2 and Z1, Z2 of the corresponding two sets of second reflective prisms in the X axis direction and the Z axis direction in real time respectively;

[0020] Step 4: Using the data obtained in step 3, calculate the displacements ΔX and ΔZ of the extended antenna 2 in the X-axis direction and the Z-axis direction, and the rotation angle θy of the extended antenna 2 around the Y-axis.

[0021] In the above step 4, the following formula is used for calculation:

[0022] ΔX=(X1+X2) / 2

[0023] ΔZ=(Z1+Z2) / 2;

[0024] θy=arctan[(Z1-Z2) / D].

[0025] The beneficial effects are: the measuring method is simple and can effectively measure the length and attitude change of the satellite-borne radar antenna baseline. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of the real-time six-degree-of-freedom measurement device for the baseline of a satellite-borne radar antenna of the present invention;

[0027] Figure 2 It is a structural schematic diagram of another perspective of the real-time six-degree-of-freedom measurement device for the baseline of a satellite-borne radar antenna of the present invention;

[0028] Figure 3 for Figure 2 A magnified view of the structure of part A;

[0029] Figure 4 The present invention is a distribution diagram of the distance measurement component, the rotation angle measurement component and the displacement measurement component of the satellite-borne radar antenna baseline real-time six-degree-of-freedom measurement device in the initial state.

[0030] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0031] 1. Satellite; 2. Extended antenna; 11. Extended arm; 31. Laser rangefinder; 32. Plane reflector; 41. Laser collimation goniometer; 42. First reflective prism; 51. Laser displacement meter; 52. Second reflective prism. DETAILED DESCRIPTION

[0032] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0033] Example 1

[0034] like Figure 1 , 2 As shown in Figures 3 and 4, the real-time six-degree-of-freedom measurement device for the base line of the satellite-borne radar antenna of this embodiment is installed on the satellite 1 and the extended antenna 2 extended at one side, and includes a distance measurement component, an angle measurement component and a displacement measurement component. A side of the satellite 1 is provided with an extendable or retractable extension arm 11, and the side of the extension arm 11 away from the satellite 1 is provided with the extended antenna 2. The distance measurement component is installed on the side of the satellite 1 and the extended antenna 2, and is used to measure the displacement change of the extended antenna 2 along the direction of its antenna base line. The angle measurement component is installed on the side of the satellite 1 and the extended antenna 2, and is used to measure the angle of rotation of the extended antenna 2 around the satellite 1 and the rotation angle around itself. The displacement measurement component is installed on the side of the satellite 1 and the extended antenna 2, and is used to measure the angle of rotation of the extended antenna 2 around the axis of the extended arm 11. In this embodiment, a fixed antenna B is installed on the side of the satellite 1.

[0035] In the real-time six-degree-of-freedom measurement device for the antenna baseline of the satellite-borne radar of this embodiment, the positions and installation angles of the ranging component, the angle measurement component and the displacement measurement component are calibrated with the positions and installation angles of the fixed antenna of the satellite. When working, the ranging component measures the displacement ΔY generated in the direction of the antenna baseline (a standard term in this field, which will not be described here, and L in the figure) of the extended antenna 2 in real time; the angle measurement component can measure the angle of rotation around the satellite 1 and the rotation angles θx and θz around itself in real time. The displacement measurement component can measure the displacement in two vertical directions of the specific marking point of the extended antenna 2 in real time, and calculate the rotation angle θy of the extended antenna 2 around the antenna baseline according to a specific logic algorithm. The above real-time measurement and calculation process completes the real-time six-degree-of-freedom measurement of the antenna baseline. The overall structural design is reasonable, and it can measure the position and angle of the extended antenna relative to the fixed antenna in real time, and then correct the radar baseline in real time to ensure the radar's on-orbit performance.

[0036] As a preferred embodiment, the distance measuring component includes a laser rangefinder 31 and a plane reflector 32. The laser rangefinder 31 is installed on the side of the satellite 1 close to the extended antenna 2, and the plane reflector 32 is installed on the side of the extended antenna 2 close to the satellite 1. The laser rangefinder 31 and the plane reflector 32 are distributed at both ends of the antenna baseline.

[0037] In the above implementation scheme, the laser emitted by the laser rangefinder 31 is reflected by the plane reflector 32 to measure the distance between the two. The real-time change difference of the distance can be used to obtain the position ΔY generated in the antenna baseline direction. The design is simple and can effectively measure the displacement change in the antenna baseline direction.

[0038] As a preferred embodiment, the angle measurement component includes a laser collimation goniometer 41 and a first reflecting prism 42. The angle measurement component is provided with at least one group. The laser collimation goniometer 41 is installed on the side of the satellite 1 close to the extended antenna 2 and close to the laser rangefinder 31. The first reflecting prism 42 is installed on the side of the extended antenna 2 close to the satellite 1 and close to the plane reflecting mirror 32.

[0039] In the above implementation scheme, the laser emitted by the laser collimator goniometer 41 is reflected by the first reflecting prism 42 and fed back to the laser collimator goniometer 41. As the real-time rotation angle changes, the difference measured in the previous and next time periods can be calculated to intuitively feed back the changes and values ​​of the rotation angles θx and θz.

[0040] In this embodiment, the above-mentioned angle measuring component is preferably provided in a group.

[0041] As a preferred embodiment, the displacement measuring component includes a laser displacement meter 51 and a second reflecting prism 52. The displacement measuring component is provided with N groups, and N is an even number. The N groups of the second reflecting prisms 52 are respectively installed on the side of the extended antenna 2 close to the satellite 1, and are symmetrically distributed on both sides of the antenna baseline. The N groups of the laser displacement meters 51 are respectively installed on the side of the satellite 1 close to the extended antenna 2, and are symmetrically distributed on both sides of the antenna baseline. The N groups of the laser displacement meters 51 and the N groups of the second reflecting prisms 52 are distributed one by one.

[0042] In the above embodiment, the two sets of displacement measurement components respectively measure the displacement changes and values ​​in two different directions, and can effectively calculate the rotation angle θy of the extended antenna 2 around the antenna baseline. The laser emitted by the laser displacement measuring instrument 51 is reflected by the second reflection prism 52 and fed back to the laser displacement measuring instrument 51.

[0043] Optimally, in this embodiment, the displacement measuring components are provided in two groups.

[0044] Optimally, in this embodiment, the laser rangefinder 31 , the laser collimation goniometer 41 and the two groups of laser displacement measuring instruments 51 are distributed on the same straight line.

[0045] Optimally, in this embodiment, the plane reflector 32 , the first reflective prism 42 and the two groups of second reflective prisms 52 are distributed on the same straight line and arranged along a side edge line extending out of the antenna 2 .

[0046] Example 2

[0047] This embodiment provides a method for measuring a satellite-borne radar antenna baseline in real time with six degrees of freedom, which is implemented using the satellite-borne radar antenna baseline real-time six degrees of freedom measurement device in Example 1, and includes the following steps:

[0048] Step 1: In the initial state, the laser rangefinder 31 faces the plane reflector 32 along the antenna baseline direction, the laser collimation goniometer 41 faces the first reflective prism 42, and the two sets of laser displacement measuring instruments 51 face the two sets of second reflective prisms 52 respectively. With the center of the satellite 1 as the origin, the antenna baseline direction is set as the Y direction, the extension direction of the extended antenna 2 is the X axis, and the direction perpendicular to the X axis and the Y axis is the Z axis. A three-dimensional space coordinate system is established (such as Figure 1 , 2 , the coordinates shown in 4);

[0049] Step 2: measuring the distance D between the laser paths (S and M in the figure represent two laser paths) respectively formed between the two sets of laser displacement measuring instruments 51 and the corresponding two sets of second reflecting prisms 52 in the initial state;

[0050] Step 3: Use the laser rangefinder 31 to measure the displacement ΔY of the extended antenna 2 on the Y axis in real time, use the laser collimation goniometer 41 to measure the rotation angles θx and θz of the extended antenna 2 around the X axis and around the Z axis in real time, and use two sets of laser displacement measuring instruments 51 to measure the displacements X1, X2 and Z1, Z2 of the corresponding two sets of second reflection prisms 52 in the X axis direction and the Z axis direction respectively in real time;

[0051] Step 4: Using the data obtained in step 3, calculate the displacements ΔX and ΔZ of the extended antenna 2 in the X-axis direction and the Z-axis direction, and the rotation angle θy of the extended antenna 2 around the Y-axis;

[0052] During the measurement process, when the measuring device is working, the laser rangefinder 31 measures the displacement ΔY of the extended antenna 2 in the Y direction in real time; the laser collimation goniometer 41 measures the rotation angles θx and θz of the extended antenna 2 around the X axis and around the Z axis in real time. The two groups of laser displacement measuring instruments 51 respectively measure the displacements X1, X2 and Z1, Z2 of the two second reflecting prisms 52 on the extended antenna 2 in the X direction and Z direction in real time, and then calculate the displacements ΔX in the X direction and Z direction of the extended antenna =(X1+X2) / 2, ΔZ=(Z1+Z2) / 2, and the rotation angle θy of the extended antenna around the Y axis =arctan[(Z1-Z2) / D]. The above real-time measurement and calculation process completes the real-time six-degree-of-freedom measurement of the antenna baseline.

[0053] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0054] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0055] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0056] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0057] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0058] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A real-time six-degree-of-freedom measurement device for a satellite-borne radar antenna baseline, mounted on a satellite (1) and an extended antenna (2) extending from one side, characterized in that: The invention comprises a distance measuring component, an angle measuring component and a displacement measuring component. A satellite (1) is provided with an extendable or retractable extension arm (11) on one side. The extension arm (11) is provided with the extension antenna (2) on one side of the end away from the satellite (1). The distance measuring component is installed on one side of the satellite (1) and the extension antenna (2) to measure the displacement change of the extension antenna (2) along the antenna baseline direction. The angle measuring component is installed on one side of the satellite (1) and the extension antenna (2) to measure the rotation angle of the extension antenna (2) around the satellite (1) and the rotation angle around itself. The displacement measuring component is installed on one side of the satellite (1) and the extension antenna (2) to measure the rotation angle of the extension antenna (2) around the axis of the extension arm (11).

2. The real-time six-degree-of-freedom measurement device for a satellite-borne radar antenna baseline according to claim 1, characterized in that: The distance measuring component comprises a laser distance meter (31) and a plane reflector (32); the laser distance meter (31) is mounted on a side of the satellite (1) close to the extended antenna (2); the plane reflector (32) is mounted on a side of the extended antenna (2) close to the satellite (1); and the laser distance meter (31) and the plane reflector (32) are distributed at both ends of the antenna baseline.

3. The real-time six-degree-of-freedom measurement device for a satellite-borne radar antenna baseline according to claim 2, characterized in that: The rotation angle measurement component comprises a laser collimation goniometer (41) and a first reflection prism (42), and the rotation angle measurement component is provided with at least one group, the laser collimation goniometer (41) is installed on a side of the satellite (1) close to the extended antenna (2) and close to the laser rangefinder (31), and the first reflection prism (42) is installed on a side of the extended antenna (2) close to the satellite (1) and close to the plane reflection mirror (32).

4. The real-time six-degree-of-freedom measurement device for a satellite-borne radar antenna baseline according to claim 3, characterized in that: The rotation angle measuring component is provided in a group.

5. A real-time six-degree-of-freedom measurement device for a satellite-borne radar antenna baseline according to claim 3 or 4, characterized in that: The displacement measurement component comprises a laser displacement measuring instrument (51) and a second reflecting prism (52). The displacement measurement component is provided with N groups, where N is an even number. The N groups of the second reflecting prism (52) are respectively installed on a side of the extended antenna (2) close to the satellite (1) and are symmetrically distributed on both sides of the antenna baseline. The N groups of the laser displacement measuring instruments (51) are respectively installed on a side of the satellite (1) close to the extended antenna (2) and are symmetrically distributed on both sides of the antenna baseline. The N groups of the laser displacement measuring instruments (51) and the N groups of the second reflecting prisms (52) are distributed in a one-to-one correspondence.

6. The real-time six-degree-of-freedom measurement device for a satellite-borne radar antenna baseline according to claim 5, characterized in that: The displacement measuring components are provided with two groups.

7. The real-time six-degree-of-freedom measurement device for a satellite-borne radar antenna baseline according to claim 6, characterized in that: The laser rangefinder (31), the laser collimation angle meter (41) and the two groups of laser displacement measuring instruments (51) are distributed on the same straight line.

8. The real-time six-degree-of-freedom measurement device for a satellite-borne radar antenna baseline according to claim 7, characterized in that: The plane reflector (32), the first reflective prism (42) and the two groups of second reflective prisms (52) are distributed on the same straight line and arranged along a side edge of the extended antenna (2).

9. A method for measuring a satellite-borne radar antenna baseline in real time with six degrees of freedom, implemented using the satellite-borne radar antenna baseline real-time six degrees of freedom measuring device as claimed in any one of claims 5 to 8, characterized in that: The following steps are involved: Step 1: In an initial state, the laser rangefinder (31) faces the plane reflector (32) along the antenna baseline direction, the laser collimation goniometer (41) faces the first reflective prism (42), and the two groups of laser displacement measuring instruments (51) face the two groups of second reflective prisms (52) respectively. The satellite center is taken as the origin, the antenna baseline direction is set as the Y direction, the extension direction of the extended antenna (2) is set as the X axis, and the direction perpendicular to the X axis and the Y axis is set as the Z axis, so as to establish a three-dimensional space coordinate system; Step 2: measuring the distance D between the laser paths respectively formed between the two groups of laser displacement measuring instruments (51) and the corresponding two groups of second reflection prisms (52) in the initial state; Step 3: Using a laser rangefinder (31), the displacement ΔY of the extended antenna (2) on the Y axis is measured in real time; using a laser collimation goniometer (41), the rotation angles θx and θz of the extended antenna (2) around the X axis and around the Z axis are measured in real time; using two sets of laser displacement measuring instruments (51), the displacements X1, X2 and Z1, Z2 of the corresponding two sets of second reflection prisms (52) in the X axis direction and the Z axis direction are measured in real time respectively; Step 4: Using the data obtained in step 3, calculate the displacements ΔX and ΔZ of the extended antenna (2) in the X-axis direction and the Z-axis direction, and the rotation angle θy of the extended antenna (2) around the Y-axis.

10. The method for real-time six-degree-of-freedom measurement of a satellite-borne radar antenna baseline according to claim 9, characterized in that: In step 4, the following formula is used for calculation: ΔX=(X1+X2) / 2 ΔZ=(Z1+Z2) / 2; θy=arctan[(Z1-Z2) / D].

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