Intelligent pulse width correction method for fine adjustment of satellite orbit height

Abstract

The application discloses a kind of intelligent pulse width correction methods when satellite orbit height fine-tuning, comprising: step S1, according to gyro information, the angular velocity variation of star body before and after track height fine-tuning thruster point injection is calculated;Step S2, according to the effect of the last two track height fine-tuning results, measure pulse width correction, update pulse width adjustment coefficient;Step S3, according to the angular velocity variation of star body calculated in the step S1 and the pulse width adjustment coefficient calculated in the step S2, calculate pulse width correction amount, determine the instruction pulse width of next track height fine-tuning thruster point injection, and return to the step S1.The application can better cope with on-orbit uncertainty and error, real-time adjustment thruster point injection pulse width makes thruster torque as far as possible offset, improves the pointing accuracy and attitude stability of star body when track height fine-tuning.

Description

Technical Field

[0001] This invention relates to satellite attitude and orbit control technology, and in particular to an on-orbit intelligent correction method for command pulse width when using thruster point injection to fine-tune satellite orbital altitude under flywheel attitude control. Background Technology

[0002] To meet the continuous observation requirements and stringent orbital altitude requirements of hyperspectral Earth observation satellite payloads, existing satellite orbital altitude fine-tuning technology utilizes thruster point injection to fine-tune orbital altitude based on flywheel attitude control. During this process, the flywheel controls the satellite's attitude, ensuring stability. When performing orbital altitude fine-tuning, a set of symmetrical nozzles is selected according to the satellite thruster installation layout, and a command pulse width is given. Ideally, the control torques generated by the two nozzles can cancel each other out.

[0003] However, the control torque generated by the nozzle in orbit is affected by various error factors, including satellite centroid deviation, nozzle installation error, and nozzle execution error. Many of these factors are unpredictable from the ground, making it difficult for the ground to set the command pulse width. If the command pulse width cannot cancel out the control torques, it will generate considerable disturbance torque, causing fluctuations in the satellite's attitude angle and angular velocity, which will adversely affect the normal operation of the payload.

[0004] In existing satellite orbital altitude fine-tuning technologies, the thruster injection command pulse width is given from the ground and cannot be adjusted. This open-loop control mode, lacking feedback, prevents further reduction of thruster interference during orbital altitude fine-tuning. Gyroscopes are an indispensable part of the satellite attitude and orbit control subsystem, feeding back the satellite's angular velocity information to the onboard computer in each control cycle. This provides the conditions for introducing closed-loop control to intelligently correct the thruster injection command pulse width in orbit. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an intelligent pulse width correction method for satellite orbital altitude fine-tuning, so as to maximize the pointing accuracy and attitude stability of the celestial body during orbital altitude fine-tuning.

[0006] To solve the above problems, the present invention is achieved through the following technical solution:

[0007] A method for intelligent pulse width correction during satellite orbital altitude fine-tuning includes:

[0008] Step S1: Calculate the change in the angular velocity of the star before and after the orbital height fine-tuning thruster is injected based on the gyroscope information.

[0009] Step S2: Based on the results of the two most recent orbital height fine-tuning adjustments, measure the effect of the pulse width correction and update the pulse width adjustment coefficient.

[0010] Step S3: Based on the change in angular velocity of the celestial body calculated in step S1 and the pulse width adjustment coefficient calculated in step S2, calculate the pulse width correction amount, determine the command pulse width for the next orbital altitude fine-tuning thruster injection, and return to step S1.

[0011] Optionally, step S1 includes: collecting the angular velocities of the planet before the thruster's injection and the first injection after the injection, and calculating the change in the planet's angular velocity before and after the thruster's injection.

[0012] Let ω be the angular velocity of the thruster one beat before the puncture. t0 The angular velocity of the first beat after the spot spray is ω t1 The change in the angular velocity of the celestial body before and after the point spray is:

[0013] Δω=ω t1 -ω t0 .

[0014] Optionally, step S2 includes: calculating a reference pulse width adjustment coefficient based on the change in angular velocity before and after pulse width correction, and determining the pulse width adjustment coefficient for the next point spray by fusion.

[0015] Optionally, step S2 further includes: due to the effect of the minimum adjustment pulse width correction amount in the previous cycle step S3, if |ΔW last |<W lim If the pulse width adjustment coefficient is not corrected, then no adjustment is made to the pulse width adjustment coefficient; otherwise, the reference pulse width adjustment coefficient α is calculated. r for

[0016]

[0017] The reference pulse width adjustment coefficient α r By combining it with the existing pulse width modulation coefficient α, a new pulse width modulation coefficient α is obtained;

[0018] W lim ΔW represents the minimum pulse width correction, and its subscript last indicates the previous calculated value of the corresponding variable; T0 is the absolute value of the nominal torque of the selected thruster; I represents the moment of inertia of the satellite.

[0019] Optionally, when the thruster is first injected, step S2 is skipped, and an existing initial value of the pulse width adjustment coefficient is used; typically, the initial value of the pulse width adjustment coefficient α is taken as ≥3.

[0020] Optionally, step S3 includes: the formula for calculating the pulse width correction is as follows:

[0021]

[0022] Where I is the satellite's moment of inertia, T0 is the absolute value of the nominal torque of the selected thruster, and α is the pulse width modulation coefficient.

[0023] Optionally, step S3 further includes: each group of orbital height fine-tuning only corrects one of the positive and negative pulse widths; the pulse width correction direction is determined by ground commands; or, determined based on the correction amount of the first pulse width that needs correction; when correcting the positive pulse width, W P =W P -ΔW,W N =W N When correcting for negative pulse width, W P =W P W N =W N +ΔW; where the initial pulse widths of the two thrusters given on the ground are W and ΔW respectively. P and W N .

[0024] This invention has at least one of the following advantages:

[0025] The present invention provides an intelligent pulse width correction method for satellite orbital altitude fine-tuning. Based on existing orbital altitude fine-tuning methods, it introduces feedback to adjust the thruster pulse width in real time. This method can better cope with the impact of on-orbit uncertainties and errors on thruster torque. By adjusting the thruster pulse width in real time, the thruster torque is offset as much as possible, thereby maximizing the pointing accuracy and attitude stability of the satellite during orbital altitude fine-tuning. This provides a platform foundation with higher precision and stability for payload operation. Attached Figure Description

[0026] Figure 1 A timing diagram of the thruster before and after injection, provided by the present invention;

[0027] Figure 2 A flowchart of an intelligent pulse width correction method for satellite orbital altitude fine-tuning provided in an embodiment of the present invention. Detailed Implementation

[0028] The intelligent pulse width correction method for satellite orbital altitude fine-tuning proposed in this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of this invention will become clearer from the following description. It should be noted that the accompanying drawings are in a very simplified form and use non-precise proportions, only for the purpose of conveniently and clearly illustrating the embodiments of this invention. Please refer to the accompanying drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention.

[0029] This embodiment provides an intelligent pulse width correction method for fine-tuning satellite orbital altitude, including:

[0030] Step S1: Calculate the change in the angular velocity of the star before and after the orbital height fine-tuning thruster is injected based on the gyroscope information.

[0031] Step S1 includes: collecting the angular velocities of the planet before the thruster's injection and the first injection after the injection, and calculating the change in the planet's angular velocity before and after the thruster's injection.

[0032] Let ω be the angular velocity of the thruster one beat before the puncture. t0 The angular velocity of the first beat after the spot spray is ω t1 The change in the angular velocity of the celestial body before and after the point spray is:

[0033] Δω=ω t1 -ω t0 .

[0034] Step S2: Based on the results of the two most recent orbital height fine-tuning adjustments, measure the effect of the pulse width correction and update the pulse width adjustment coefficient.

[0035] Step S2 includes: calculating a reference pulse width adjustment coefficient based on the change in angular velocity before and after pulse width correction, and determining the pulse width adjustment coefficient for the next point spray by fusion.

[0036] Step S2 further includes: due to the effect of the minimum adjustment pulse width correction amount in the previous cycle step S3, if |ΔW last |<W lim If the pulse width adjustment coefficient is not corrected, then no adjustment is made to the pulse width adjustment coefficient; otherwise, the reference pulse width adjustment coefficient α is calculated. r for

[0037]

[0038] The reference pulse width adjustment coefficient α r By combining it with the existing pulse width modulation coefficient α, a new pulse width modulation coefficient α is obtained.

[0039] W lim ΔW represents the minimum pulse width correction, and its subscript last indicates the previous calculated value of the corresponding variable; T0 is the absolute value of the nominal torque of the selected thruster; I represents the moment of inertia of the satellite.

[0040] In this embodiment, when the thruster is first injected, step S2 is skipped and the existing initial value of the pulse width adjustment coefficient is used; to avoid divergence, the initial value of the pulse width adjustment coefficient α is usually taken as ≥3.

[0041] Step S3: Based on the change in angular velocity of the celestial body calculated in step S1 and the pulse width adjustment coefficient calculated in step S2, calculate the pulse width correction amount, determine the command pulse width for the next orbital altitude fine-tuning thruster injection, and return to step S1.

[0042] Step S3 includes: the formula for calculating the pulse width correction is as follows:

[0043]

[0044] Where I is the satellite's moment of inertia, T0 is the absolute value of the nominal torque of the selected thruster, and α is the pulse width modulation coefficient.

[0045] Step S3 further includes: to avoid weakening the orbit control effect by alternating positive and negative pulse width corrections, each group of orbit height fine-tuning only corrects one of the positive and negative pulse widths; the pulse width correction direction is determined by ground commands; or, it is determined based on the correction amount of the first pulse width that needs correction; when correcting the positive pulse width, W P =W P -ΔW,W N =W N When correcting for negative pulse width, W P =W P W N =W N +ΔW; where the initial pulse widths of the two thrusters given on the ground are W and ΔW respectively. P and W N .

[0046] To avoid repeatedly fine-tuning the command pulse width, a minimum pulse width correction amount W is set. lim If |ΔW|<W lim If so, then no pulse width correction will be performed this time.

[0047] The coordinate axes for algorithm application are determined based on the main direction of the torque generated by the selected thruster. The angular velocity is selected as the component of the corresponding axis, the inertia is selected as the principal inertia of the corresponding axis, and the thruster torque is selected as the torque generated on the corresponding axis.

[0048] To better understand the above embodiments, a specific example will be given below for detailed explanation.

[0049] like Figure 1 As shown, two thruster nozzles with a basically symmetrical layout and thrust along the +X direction of the satellite body are selected. The main directions of the torque generated by the two nozzles are the +Y and -Y directions of the satellite body, respectively (represented by the subscripts "P" and "N"). The pitching moments generated under nominal conditions are 3.5 Nm and -3.5 Nm, respectively. This example is used to illustrate the implementation of this method.

[0050] Since the main direction of the torque generated by the selected thrust is the pitch direction of the celestial body, this algorithm will be applied to the pitch axis, with the angular velocity selected as the pitch axis component and the inertia selected as the principal inertia I of the pitch axis. y .

[0051] Now, a set of orbital altitude fine-tuning steps will be performed. The initial pulse width for both thrusters is given by the ground as W. P =W N =100ms. Assuming various error factors, the actual torques generated by the two thrusters are 3.7Nm and -3.2Nm, respectively. The thrusters will generate interfering torques by spraying according to the initial pulse width, causing changes in the angular velocity of the planet before and after the spray.

[0052] like Figure 2 As shown, the first loop:

[0053] Step S1: Collect the angular velocities of the planet before and after the thruster's puncture, and calculate the change in the planet's angular velocity before and after the thruster's puncture. Let ω be the pitch angular velocity of the planet before the thruster's puncture. yt0 The pitch velocity of the first beat after the spot spray is ω yt1 The change in the pitch angular velocity of the celestial body before and after the point spray is Δω y =ω yt1 -ω yt0 .

[0054] Step S2 will not be executed initially, and the initial value of the pulse width adjustment coefficient can be α = 3.

[0055] Step S3: Based on the change in celestial angular velocity calculated in Step S1 and the pulse width adjustment coefficient calculated in Step S2, calculate the pulse width correction amount:

[0056]

[0057] Where T0 = 3.5 Nm is the nominal torque of the selected thruster.

[0058] The calculated value is ΔW = 8ms. To conserve propellant, this round of trajectory height fine-tuning will only correct the positive pulse width. The pulse width for the next injection will be W. P =92ms, W N =100ms, and spray at this pulse width.

[0059] Second cycle:

[0060] Step S1: Continue calculating the change in the angular velocity of the celestial body's pitch before and after the point spray Δω y ;

[0061] Step S2: Calculate the reference pulse width adjustment coefficient α based on the pitch angular velocity changes of the two most recent injections and the pulse width correction amount of the previous cycle. r

[0062]

[0063] α r It can be fused with existing pulse width modulation coefficient α, for example, by selecting appropriate weighting coefficient λ. r A weighted fusion method is used:

[0064]

[0065] After fusion, the current beat α = 2.1.

[0066] Step S3: Based on the angular velocity change of the celestial body calculated in Step S1 and the pulse width adjustment coefficient calculated in Step S2, calculate the pulse width correction ΔW = 4ms. The pulse width of the next pulse spray is W. P =88ms, W N =100ms, and spray at this pulse width.

[0067] Third cycle: α = 1.5, ΔW = 1ms, W P =87ms, W N =100ms;

[0068] Fourth cycle: α = 1.1, ΔW = 0.8ms. If the minimum pulse width correction W is set... lim =1ms, then no pulse width correction is performed in this loop, i.e., W P =87ms, W N =100ms. The pulse width adjustment coefficient will not be updated in the next cycle. The pulse width correction ΔW will continue to be calculated until |ΔW|≥W occurs again. lim .

[0069] In summary, this embodiment provides an intelligent pulse width correction method for satellite orbital altitude fine-tuning. By introducing angular velocity feedback during orbital altitude fine-tuning, the method corrects the thruster pulse width based on the changes in satellite angular velocity before and after thruster injection, and introduces a pulse width correction coefficient to enhance the correction effect. The intelligent pulse width correction method of this invention can better cope with on-orbit uncertainties and errors, adjusting the thruster pulse width in real time to minimize thruster torque cancellation, thereby improving the pointing accuracy and attitude stability of the satellite during orbital altitude fine-tuning.

[0070] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0071] It should be noted that the apparatus and methods disclosed in the embodiments herein can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings show the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments herein. In this regard, each block in a flowchart or block diagram may represent a module, program, or part of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system to perform the specified function or action, or can be implemented using a combination of dedicated hardware and computer instructions.

[0072] In addition, the functional modules in the various embodiments of this article can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0073] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A method for intelligent pulse width correction during satellite orbital altitude fine-tuning, characterized in that, include: Step S1: Calculate the change in the angular velocity of the star before and after the orbital height fine-tuning thruster is injected based on the gyroscope information; Step S2: Based on the results of the two most recent orbital height fine-tuning adjustments, measure the effect of the pulse width correction and update the pulse width adjustment coefficient; Step S2 includes: calculating the reference pulse width adjustment coefficient based on the change in angular velocity before and after pulse width correction, and determining the pulse width adjustment coefficient for the next point spray by fusion. Due to the effect of the minimum adjustment pulse width correction amount in the previous loop step S3, if If the pulse width adjustment coefficient is not corrected, then no adjustment is made to the pulse width adjustment coefficient; otherwise, the reference pulse width adjustment coefficient is calculated. for Reference pulse width adjustment coefficient Compared with existing pulse width adjustment coefficients Fusion yields a new pulse width modulation coefficient. ; This represents the minimum pulse width correction amount. This indicates the calculation of the pulse width correction, and its subscript last indicates the previous calculated value of the corresponding variable; The absolute value of the nominal torque of the selected thruster; I represents the moment of inertia of the satellite; This indicates the change in the angular velocity of the celestial body before and after the point spray; Step S3: Based on the change in angular velocity of the star calculated in step S1 and the pulse width adjustment coefficient calculated in step S2, calculate the pulse width correction amount, determine the command pulse width for the next orbital altitude fine-tuning thruster injection, and return to step S1. Step S3 further includes: Each group of track height fine-tuning only corrects one of the positive and negative pulse widths; The direction of pulse width correction is determined by ground commands; or, it is determined based on the amount of the first pulse width correction required. When correcting the positive pulse width, , ; When correcting negative pulse width, , ; In the formula, This represents the pulse width correction amount. The initial pulse widths of the two thrusters given on the ground are respectively... W P and W N .

2. The intelligent pulse width correction method for satellite orbital altitude fine-tuning as described in claim 1, characterized in that, Step S1 includes: collecting the angular velocities of the planet before the thruster's injection and the first injection after the injection, and calculating the change in the planet's angular velocity before and after the thruster's injection. Let the angular velocity of the thruster one beat before the puncture be . The angular velocity of the first beat after the spot spray is The change in the angular velocity of the celestial body before and after the point spray is: 。 3. The intelligent pulse width correction method for satellite orbital altitude fine-tuning as described in claim 1, characterized in that, When initially injecting the thruster, skip step S2 and use the existing initial value of the pulse width adjustment coefficient; typically, the initial value of the pulse width adjustment coefficient is used. .

4. The intelligent pulse width correction method for satellite orbital altitude fine-tuning as described in claim 1, characterized in that, Step S3 includes: the formula for calculating the pulse width correction is as follows: in, For the satellite's moment of inertia, The absolute value of the nominal torque of the selected thruster. This is the pulse width adjustment coefficient.

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