Adaptive variable step size simulation method for aerospace system with very high time-frequency precision

Abstract

The invention discloses an adaptive variable step size simulation method for an aerospace system with very high time-frequency precision, and belongs to the field of aerospace system simulation. The problems that under the premise of being compatible with an existing spaceflight simulation framework, time precision has a bottleneck, and dynamic adaptation of simulation step length is difficult to achieve are solved. The method comprises the steps that a main clock and a sub clock are arranged, the main clock uses Julian day timing (time is expressed as T), and the sub clock uses second as a unit (time is expressed as t). And when the simulation time precision demand exceeds the precision of the main clock, the main clock and the sub-clock are synchronously timed, and the simulation time is formed by linear superposition of T and t. And when the time of the sub-clock exceeds the minimum step length delta T of the main clock, the time of the sub-clock is partially carried to the main clock, and the time of the main clock is updated. And calculating a time-varying simulation quantity by adopting first-order Taylor expansion and superposing a state quantity. And dynamically adjusting the sub-clocks. When delta t is greater than or equal to delta T, freezing the sub-clock, and only timing by the main clock; and when delta t is smaller than or equal to delta T, the sub-clock is reactivated. The method is mainly used for ultrahigh-frequency aerospace tasks.

Description

Technical Field

[0001] The present invention belongs to the field of aerospace system simulation, and particularly relates to an adaptive variable-step simulation method for aerospace systems with very high time-frequency accuracy. Background Art

[0002] In the field of aerospace system simulation, time accuracy is one of the core factors affecting the reliability of simulation results. Currently, mainstream aerospace system simulation software generally uses Julian Date as the time reference unit and combines double-precision floating-point (double) type for time calculation. Julian Date can effectively unify the description of different time periods by converting Gregorian time into continuous days (starting from noon on January 1, 4713 BC), which is convenient for long-time-span simulations in scenarios such as orbital dynamics and ephemeris calculation. Since the effective number of digits of the double-precision floating-point type is about 16 bits, after deducting the integer part of Julian Date (occupying about 7 significant digits), its time resolution is about 10 -9 days (i.e., 10 -4 seconds). Although this accuracy can meet the requirements of traditional scenarios such as orbital recursion and attitude control, in emerging applications such as high-frequency remote sensing satellite imaging, space-based precise time synchronization, and laser communication terminal alignment, the simulation step size needs to reach the microsecond (10 -6 seconds) or even nanosecond (10 -9 seconds) level, and the problem of insufficient accuracy of existing methods is becoming increasingly prominent.

[0003] Taking high-line-frequency remote sensing satellite imaging as an example, to verify the effectiveness of the image motion compensation algorithm, the simulation needs to accurately simulate the migration process of photons between pixels, requiring the time step to be strictly matched with the pixel exposure time (for example, at the 7-microsecond level). If traditional Julian Date timing is used, the time quantization error will cause the image motion compensation deviation to be amplified, and the simulation image will appear severely blurred and cannot be used for algorithm verification. Similarly, in the space-based spatio-temporal alignment scenario, nanosecond-level time synchronization errors will directly cause kilometer-level position deviations, seriously affecting the credibility of the simulation results. In addition, existing simulation tools usually adopt a fixed-step strategy and are difficult to adapt to the time accuracy requirements that change dynamically during the mission phase. For example, during the non-operating period of satellite payloads (such as when the camera is pointing to space), if a high-precision simulation step size is still maintained, it will lead to a sharp increase in the amount of ineffective calculations (such as the number of simulation steps increasing from dozens to millions), significantly reducing the simulation efficiency.

[0004] In view of the above problems, the existing technologies have tried to improve the simulation accuracy by optimizing numerical algorithms or enhancing hardware computing power, but have not fundamentally solved the inherent limitations of the time representation method. For example, directly adopting a higher-precision data type (such as 128-bit floating point) can improve the resolution, but will greatly increase the consumption of computing resources and has poor compatibility with existing simulation software. Another approach is to switch the time unit from "day" to "second", but such changes require reconstructing the time management system and may introduce compatibility issues between the orbital dynamics model and the time reference. Therefore, how to break through the time accuracy bottleneck and achieve dynamic adaptation of the simulation step size while being compatible with the existing aerospace simulation framework has become a technical problem to be solved urgently. Summary of the Invention

[0005] In view of this, the present invention aims to propose an adaptive variable-step simulation method for aerospace systems with very high time-frequency accuracy to solve the problem that there are bottlenecks in time accuracy and it is difficult to achieve dynamic adaptation of the simulation step size while being compatible with the existing aerospace simulation framework.

[0006] To achieve the above object, the present invention adopts the following technical solutions: An adaptive variable-step simulation method for aerospace systems with very high time-frequency accuracy, the method comprising:

[0007] Step S1: Set a master clock and a slave clock in the aerospace system simulation software. The master clock uses Julian Day as the time unit, and the time is represented as T. The slave clock uses seconds as the time reference, and the time is represented as t;

[0008] Step S2: When the simulation time accuracy requirement exceeds the accuracy range of the master clock, synchronize the timing of the master clock and the slave clock, and the system simulation time is composed of the linear superposition of the master clock time T and the slave clock time t;

[0009] Step S3: When the cumulative time of the slave clock exceeds the minimum simulation step size ΔT of the master clock, carry the part corresponding to ΔT in the slave clock time to the master clock, update the master clock time to T + ΔT, and adjust the slave clock time to t - ΔT;

[0010] Step S4: Calculate the time-varying simulation quantity by using the first-order Taylor expansion method, and superimpose the state quantity at the time T + t;

[0011] Step S5: Dynamically adjust the availability of the slave clock according to the real-time simulation step size requirement: when the simulation step size Δt increases to more than ΔT, freeze the slave clock and only use the master clock for timing; when Δt decreases to less than ΔT, re-enable the slave clock and use the process described in Step S3 for timing.

[0012] Further, a preferred method is also proposed. When the slave clock in Step S1 uses seconds as the time unit, it is implemented by the double type to achieve 10 -15Simulation step accuracy at the second level.

[0013] Furthermore, a preferred method is also proposed. In step S2, the master clock time T is obtained through the Julian day calculation formula, and the specific formula is:

[0014]

[0015] where INT() is the integer function, Year represents the year, Month represents the month, Day represents the day, Hour represents the hour, Minute represents the minute, and Second represents the second.

[0016] Furthermore, a preferred method is also proposed. The carry operation trigger condition in step S3 is t > ΔT. After the carry, the master clock time is updated to T + ΔT, and the slave clock time is updated to t - ΔT.

[0017] Furthermore, a preferred method is also proposed. In step S4, the calculation of the time-varying simulation quantity is calculated through the Taylor expansion of the spacecraft position vector:

[0018]

[0019] where R(T) is the position vector at time T, V(T) is the corresponding velocity vector, is the derivative of the position vector with respect to time.

[0020] Furthermore, a preferred method is also proposed. In step S5, the dynamic adjustment of the slave clock availability is triggered by a preset instruction. When it is detected that the simulation step Δt > ΔT, the slave clock timing function is frozen. When Δt < ΔT, the slave clock and the master clock are reactivated for coordinated timing.

[0021] Furthermore, a preferred method is also proposed. The method further includes: automatically enabling the slave clock when the simulation step requirement is at the microsecond level, and switching to the master clock independent timing mode when the simulation step requirement is amplified to the second level.

[0022] Furthermore, a preferred method is also proposed. The method further includes: real-time monitoring of the cumulative time of the slave clock during the simulation process, and automatically performing a carry operation when t reaches an integer multiple of ΔT.

[0023] Based on the same inventive concept, the present invention also proposes a computer device, including a memory and a processor. A computer program is stored in the memory. When the processor runs the computer program stored in the memory, the processor executes an adaptive variable-step simulation method for a space system with very high time-frequency accuracy according to any one of the above.

[0024] Based on the same inventive concept, the present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is run by a processor, it executes the steps of an adaptive variable-step simulation method for a space system with very high time-frequency accuracy as described in any one of the above.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. In the method proposed by the present invention, by introducing a cooperation mechanism between a sub-clock (timing in seconds or smaller units) and a master clock (Julian day timing), the simulation time resolution is improved from 10 -4 seconds of the traditional Julian day to 10 -15 seconds of the sub-clock (when using the double type), which can support the simulation requirements of step sizes at the microsecond, nanosecond, or even picosecond level. For example, in the simulation of high-line-frequency remote sensing satellite imaging, this method successfully achieved the verification of image motion compensation with a 7-microsecond step size and a 10-nanosecond accuracy. The clarity of the simulated images is significantly better than that of the traditional method, effectively avoiding the problem of image blurring caused by time quantization errors.

[0027] 2. In the method proposed by the present invention, through the instruction-driven sub-clock freezing and activation mechanism, the system can automatically switch the time accuracy mode according to the requirements of the simulation stage. For example, during the non-working period of the satellite payload (such as when the camera is pointing to space), the simulation step size is adjusted from 7 microseconds to 0.5 seconds (using only the master clock), the number of simulation steps is reduced from 2.02 million steps to 29 steps, and the calculation time consumption is reduced by about 99.9%, significantly saving computing resources while ensuring the high-precision simulation requirements during the working period.

[0028] 3. In the method proposed by the present invention, the Julian day timing method of the master clock is retained, which is completely compatible with the existing orbit dynamics model and ephemeris calculation module, and there is no need to modify the underlying time management system. The sub-clock is embedded as an independent module, and only the time synchronization interface needs to be extended, reducing the complexity of system upgrade. In addition, by calculating the time variable through the first-order Taylor expansion, the calculation burden introduced by high-complexity algorithms is avoided while ensuring the accuracy.

[0029] 4. In the method proposed by the present invention, when the cumulative time of the sub-clock exceeds the minimum step size of the master clock, a carry operation is automatically executed to ensure that the time superposition of the master clock and the sub-clock is strictly equivalent to that of a single high-precision clock, avoiding the accumulation of timing deviations caused by long-term simulation. This mechanism has verified that the time synchronization error is less than 10 -128 seconds in the microsecond-level continuous imaging simulation, meeting the high-precision space-time alignment requirements.

[0030] 5. The method proposed by the present invention supports the configurability of the sub-clock timing unit (such as seconds, nanoseconds, picoseconds), and can further adapt to the sub-picosecond-level simulation requirements by adjusting the data type (such as extended precision floating point). This method has been successfully applied to multiple scenarios such as high-frequency remote sensing imaging, space-based laser communication alignment, and deep space probe autonomous navigation. The simulation accuracy has been improved by 3 to 5 orders of magnitude compared with traditional methods, providing a general technical basis for future ultra-high-frequency space mission simulations. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0032] Figure 1 It is a dynamic adjustment flowchart of the adaptive variable step size simulation method for a space system with extremely high time-frequency accuracy described in Embodiment 1;

[0033] Figure 2 It is a schematic diagram of the simulation image of the rotating scan satellite urban area described in Embodiment 11, Figure 2 (a) The simulation image without enabling the sub-clock (simulation step size 10 -4 s), Figure 2 (b) The simulation image with the sub-clock enabled;

[0034] Figure 3 It is a schematic diagram of the simulation images of two consecutive strips of the rotating scan satellite described in Embodiment 11. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention can be combined with each other. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0036] Embodiment 1. Refer to Figure 1 This embodiment will be described. An adaptive variable step size simulation method for a space system with extremely high time-frequency accuracy described in this embodiment includes:

[0037] Step S1: Set the master clock and the sub-clock in the space system simulation software. The master clock uses the Julian day as the timing unit, and the time is represented as T. The sub-clock uses seconds as the timing reference, and the time is represented as t;

[0038] Step S2: When the simulation time accuracy requirement exceeds the accuracy range of the master clock, the master clock and the sub-clock are used for synchronous timing, and the system simulation time is composed of the linear superposition of the master clock time T and the sub-clock time t;

[0039] Step S3: When the cumulative time of the sub - clock exceeds the minimum simulation step size ΔT of the master clock, carry the part corresponding to ΔT in the sub - clock time to the master clock, update the master clock time to T + ΔT, and adjust the sub - clock time to t - ΔT;

[0040] Step S4: Calculate the time - varying simulation quantity using the first - order Taylor expansion method and superimpose the state quantity at time T + t;

[0041] Step S5: Dynamically adjust the availability of the sub - clock according to the real - time simulation step size requirement: When the simulation step size Δt increases above ΔT, freeze the sub - clock and only use the master clock for timing; when Δt decreases below ΔT, re - enable the sub - clock and use the process described in Step S3 for timing.

[0042] The method proposed in this embodiment, by introducing a cooperation mechanism between the sub - clock (timing in seconds or smaller units) and the master clock (Julian day timing), the simulation time resolution is improved from 10 -4 seconds of the traditional Julian day to 10 -15 seconds magnitude of the sub - clock (when using double type), which can support the simulation requirements of microsecond, nanosecond or even picosecond - level step sizes. For example, in the simulation of high - line - frequency remote - sensing satellite imaging, this method successfully realizes the verification of image motion compensation with a 7 - microsecond step size and 10 - nanosecond accuracy. The clarity of the simulated image is significantly better than the traditional method, effectively avoiding the image blurring problem caused by time quantization error.

[0043] The method proposed in this embodiment, through the instruction - driven sub - clock freezing and activation mechanism, the system can automatically switch the time - accuracy mode according to the simulation stage requirements. For example, during the non - working period of the satellite payload (such as when the camera points to space), adjust the simulation step size from 7 microseconds to 0.5 seconds (only use the master clock), the number of simulation steps is reduced from 2.02 million steps to 29 steps, and the calculation time consumption is reduced by about 99.9%, significantly saving computing resources while ensuring the high - accuracy simulation requirements during the working period.

[0044] The method proposed in this embodiment retains the Julian day timing method of the master clock, is fully compatible with the existing orbit dynamics model and ephemeris calculation module, and does not require modification of the underlying time management system. The sub - clock is embedded as an independent module, and only the time synchronization interface needs to be extended, reducing the system upgrade complexity. In addition, calculating time - varying quantities through the first - order Taylor expansion avoids the computational burden introduced by high - complexity algorithms while ensuring accuracy.

[0045] The method proposed in this embodiment supports the configurability of the sub-clock timing unit (such as seconds, nanoseconds, picoseconds), and can further adapt to the sub-picosecond-level simulation requirements by adjusting the data type (such as extended precision floating point). This method has been successfully applied to multiple scenarios such as high-frequency remote sensing imaging, space-based laser communication alignment, and deep-space probe autonomous navigation. The simulation accuracy has been improved by 3 to 5 orders of magnitude compared with traditional methods, providing a general technical basis for future ultra-high-frequency space mission simulations.

[0046] Embodiment 2: This embodiment further limits a self-adaptive variable-step simulation method for a space system with extremely high time-frequency accuracy described in Embodiment 1. When the sub-clock in step S1 uses seconds as the timing unit, the simulation step accuracy of the order of 10 -15 seconds is achieved through the double type.

[0047] In a space system, extremely high-precision time-frequency analysis is often involved, especially when precise control and prediction of the orbit, position, or speed of a spacecraft are required. The accuracy of 10 -15 seconds enables this simulation method to adapt to scenarios with extremely high-precision requirements such as high-speed spacecraft and deep-space exploration. By using the double type and setting the high precision of the sub-clock, the simulation system can provide a more flexible and accurate simulation step, thus better simulating the actual situation.

[0048] Embodiment 3: This embodiment further limits a self-adaptive variable-step simulation method for a space system with extremely high time-frequency accuracy described in Embodiment 1. In step S2, the main clock time T is obtained through the Julian day calculation formula, and the specific formula is:

[0049]

[0050] where INT() is the integer function, Year represents the year, Month represents the month, Day represents the day, Hour represents the hour, Minute represents the minute, and Second represents the second.

[0051] Embodiment 4: This embodiment further limits a self-adaptive variable-step simulation method for a space system with extremely high time-frequency accuracy described in Embodiment 1. The carry operation trigger condition in step S3 is t > ΔT. After the carry, the main clock time is updated to T + ΔT, and the sub-clock time is updated to t - ΔT.

[0052] In this embodiment, through the self-adaptive variable-step simulation method, the step size can be adjusted according to real-time needs instead of using a fixed step size. This method can better adapt to the complex and changeable space environment. As time goes by, the accuracy requirements of the system will change. The use of the dynamic adjustment carry trigger condition t > ΔT enables the system to perform more precise control according to the current state.

[0053] By controlling the carry operation under such conditions, the time accuracy can be guaranteed without the need for frequent time updates. Compared with the traditional simulation method with fixed accuracy, this adaptive variable-step method reduces unnecessary calculations, thereby improving the simulation efficiency. Especially in applications such as aerospace systems that have high requirements for computing resources, it can significantly reduce the computational load.

[0054] Embodiment 5: This embodiment further limits a method for adaptive variable-step simulation of an aerospace system with very high time-frequency accuracy described in Embodiment 1. In step S4, the calculation of the time-varying simulation quantity is performed by the Taylor expansion of the spacecraft position vector:

[0055]

[0056] where R(T) is the position vector at time T, and V(T) is the corresponding velocity vector, is the derivative of the position vector with respect to time.

[0057] Embodiment 6: This embodiment further limits a method for adaptive variable-step simulation of an aerospace system with very high time-frequency accuracy described in Embodiment 1. In step S5, the availability of the sub-clock is dynamically adjusted by a preset instruction. When it is detected that the simulation step size Δt > ΔT, the timing function of the sub-clock is frozen. When Δt < ΔT, the cooperative timing of the sub-clock and the master clock is reactivated.

[0058] In this embodiment, by dynamically adjusting the availability of the sub-clock and freezing the timing function of the sub-clock when the simulation step size Δt is greater than the preset threshold ΔT, the influence of the step size change on the accuracy can be effectively controlled. When the step size is small, reactivating the cooperative timing of the sub-clock and the master clock can ensure the precise synchronization of the clocks during the simulation, avoiding accuracy loss. Especially in an aerospace system with high-precision time-frequency requirements, the high time-frequency accuracy of the simulation is ensured.

[0059] Freezing the timing function of the sub-clock when Δt is greater than ΔT can avoid performing operations on the sub-clock under unnecessary circumstances, thereby saving computing resources and processing time. Only when Δt is less than ΔT can the cooperative timing of the sub-clock and the master clock be activated, which improves the operating efficiency of the system and reduces unnecessary computational overhead.

[0060] Embodiment 7: This embodiment further limits a method for adaptive variable-step simulation of an aerospace system with very high time-frequency accuracy described in Embodiment 1. The method further includes: automatically enabling the sub-clock when the simulation step size requirement is in the microsecond level, and switching to the independent timing mode of the master clock when the simulation step size requirement is magnified to the second level.

[0061] Embodiment VIII. This embodiment further defines a simulation method with extremely high time-frequency accuracy for an aerospace system with adaptive variable step length described in Embodiment I. The method further includes: during the simulation process, the cumulative time of the sub-clock is monitored in real time, and when t reaches an integer multiple of ΔT, a carry operation is automatically performed.

[0062] Embodiment IX. A computer device described in this embodiment includes a memory and a processor. A computer program is stored in the memory. When the processor runs the computer program stored in the memory, the processor executes a simulation method with extremely high time-frequency accuracy for an aerospace system with adaptive variable step length described in any one of Embodiments I to VIII.

[0063] Embodiment X. A computer-readable storage medium described in this embodiment has a computer program stored thereon. When the computer program is run by a processor, it executes the steps of a simulation method with extremely high time-frequency accuracy for an aerospace system with adaptive variable step length described in any one of Embodiments I to VIII.

[0064] Embodiment XI. Refer to Figure 2 and Figure 3 to describe this embodiment. This embodiment provides a specific example for a simulation method with extremely high time-frequency accuracy for an aerospace system with adaptive variable step length described in Embodiment I, and is also used to explain Embodiments II to VIII. Specifically:

[0065] (1) Master clock and sub-clock settings

[0066] Current common aerospace system simulation software all uses Julian Day for timing, and the data type is double type, which is used to calculate information such as spacecraft orbits, Earth rotation, and solar system ephemeris. The Julian Day is the number of days starting from 12:00 on January 1, 4573 BC. By converting the Gregorian calendar date into Julian Day, the difference between two Gregorian calendar moments can be obtained under a unified specification, which is convenient for formulating the simulation step length.

[0067] The formula for calculating Julian Day from the Gregorian calendar is:

[0068]

[0069] where INT() is the integer function. It can be seen from this that if the Julian Day is represented by the double type, the number of significant digits it can provide is about 16 bits. After removing the integer part (7 significant digits), the time accuracy that can be characterized is within 10 -9 days (that is, 10 -4s) Magnitude. This precision can well meet the requirements of scenarios such as high-precision orbit recurrence, but it is difficult to apply to simulation scenarios at the microsecond or even nanosecond level, such as high line frequency remote sensing satellite imaging simulation and high-precision space-time alignment.

[0070] To overcome the above problems and improve the time precision of the simulation system, in this embodiment, a master clock and a slave clock are designed in the aerospace system simulation software. The master clock still uses the Julian day as the time unit, the time is represented as T, and the minimum simulation step size is represented as ΔT; the slave clock uses seconds or a smaller step size as the time unit, the time is represented as t, and the system simulation step size is represented as Δt. When the slave clock uses seconds as the time unit, when using the double type, the simulation step size of the slave clock can reach 10 -15 s magnitude, so as to support very high time-frequency and high-precision aerospace system simulations with nanosecond or even picosecond step sizes.

[0071] (2) Timing rules

[0072] For scenarios where the simulation time precision exceeds the precision range of the master clock (that is, the simulation time step is less than ΔT), the master clock and the slave clock are used for synchronous timing. At this time, the system simulation time is the sum of the two clock times (T + t). When the total time of the slave clock exceeds the minimum value of the master clock timing step (that is, t > ΔT), the corresponding time of the slave clock is carried over to the master clock. At this time, the master clock time changes to (T + ΔT), and the slave clock time changes to (t - ΔT), and then the next step of timing continues.

[0073] (3) Solution of time-varying simulation quantities

[0074] For the time-varying simulation quantities in the simulation system, the first-order Taylor expansion method can be used for calculation. For example, if the position vector of the spacecraft at time T is R(T), then the position vector at time (T + t) is

[0075] &

[0076] R(T + t) = R(T) + R(T)t = R(T) + V(T)t

[0077] where V(T) is the velocity vector of the spacecraft.

[0078] (4) Dynamic adjustment of time precision

[0079] According to the simulation time precision requirements, instruction information can be set in the simulation system to change the system simulation step size, so as to dynamically adjust the availability of the slave clock at any time. The general process is as Figure 1As shown. When the simulation step size Δt is suddenly enlarged to within the master clock accuracy range (i.e., Δt > ΔT), the system will freeze the slave clock and directly use the master clock for timing; when the simulation step size is reduced to outside the master clock accuracy range (i.e., Δt < ΔT), the system will re-enable the slave clock and still use the process described in step (2) for timing.

[0080] A specific embodiment is given below. Patent CN107152926A proposes a method for a satellite to achieve ultra-wide swath earth imaging by rotating and scanning. The payload of this satellite is an optical camera that rotates at high speed around the satellite velocity direction and uses the TDI linear array scanning method for imaging. It is necessary to verify the correctness of the payload image motion compensation method through image simulation. This simulation scenario requires that the ground object just moves one pixel within the image plane in one time step. After calculation, this time step is about 7 microseconds, and the step accuracy must be better than 10 nanoseconds, which far exceeds the time simulation accuracy ability of the Julian day. And if a 10 -4 s simulation step size is used for simulation, the image motion compensation error caused by insufficient time accuracy will be magnified by more than 10 times.

[0081] Use the simulation method described in the present invention to perform image simulation on a certain urban area, as Figure 2 shown. Among them, Figure 2 (a) is the simulation image without enabling the slave clock (simulation step size 10 -4 s). At this time, the image motion blur is serious, and the detail features cannot be distinguished at all, and it cannot be used for subsequent applications; while Figure 2 (b) is the simulation image with the slave clock enabled. It can be seen that the image quality of the satellite is very clear, thus effectively verifying the accuracy of the image motion compensation algorithm and proving that the very high time-frequency simulation method proposed by the present invention will not cause errors in the system due to insufficient time accuracy at ultra-short simulation step sizes.

[0082] Subsequently, since the camera will have a period of time when the optical axis points to space and is not in the working state in the rotating and scanning mode, two sets of commands with an interval of 14.5 s are set. When the optical axis of the camera leaves the earth, the system simulation step size is adjusted to 0.5 s to quickly skip the non-working period, and then the simulation step size is adjusted back to about 7 microseconds, so that complete images of two consecutive strips can be obtained, as Figure 3 shown. By dynamically adjusting the simulation step size and the availability of the slave clock, only 29 steps need to be simulated during the non-working period, while if the slave clock is always used, more than 2.02 million steps need to be simulated, resulting in a large amount of time waste, further illustrating the effectiveness of the time accuracy dynamic adjustment method described in the present invention.

[0083] The specific embodiments of the present invention disclosed above are only used to help illustrate the present invention. The specific embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. According to the content of this specification, many modifications and variations can be made. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and utilize the present invention.

Claims

1. An adaptive variable step-size simulation method for aerospace systems with very high time-frequency accuracy, characterized in that: The method comprises: Step S1: setting a master clock and a sub-clock in the aerospace system simulation software, wherein the master clock uses the Julian day as a timing unit, and the time is expressed as T, and the sub-clock uses seconds as a timing reference, and the time is expressed as t; Step S2: When the simulation time accuracy requirement exceeds the master clock accuracy range, the master clock and the slave clock are used for synchronous timing, and the system simulation time is composed of the linear superposition of the master clock time T and the slave clock time t; Step S3: When the accumulated time of the sub-clock exceeds the minimum simulation step length ΔT of the main clock, the part of the sub-clock time corresponding to ΔT is carried to the main clock, and the main clock time is updated to T+ΔT, and the sub-clock time is adjusted to t-ΔT; Step S4: Calculate the time-varying simulation quantity using the first-order Taylor expansion method, and superimpose the state quantity at time T+t; Step S5: Dynamically adjust the sub-clock availability according to the real-time simulation step requirements: when the simulation step Δt increases to above ΔT, freeze the sub-clock and only use the main clock for timing; when Δt decreases to below ΔT, re-enable the sub-clock and use the process described in step S3 for timing.

2. The method for adaptive variable step-size simulation of aerospace system with very high time-frequency accuracy according to claim 1, characterized in that: In step S1, when the sub-clock uses seconds as the timing unit, 10 is implemented by double type. -15 Simulation step accuracy in seconds.

3. The method for adaptive variable step-size simulation of aerospace system with very high time-frequency accuracy according to claim 1, characterized in that: In step S2, the master clock time T is obtained by the Julian day calculation formula, and the specific formula is: Among them, INT() is a rounding function, Year represents year, Month represents month, Day represents day, Hour represents hour, Minute represents minute, and Second represents second.

4. The method for adaptive variable step-size simulation of aerospace system with very high time-frequency accuracy according to claim 1, characterized in that: The trigger condition of the carry operation in step S3 is t>ΔT. After the carry, the main clock time is updated to T+ΔT, and the sub-clock time is updated to t-ΔT.

5. The method for adaptive variable step-size simulation of aerospace system with very high time-frequency accuracy according to claim 1, characterized in that: The calculation of the time-varying simulation quantity in step S4 is performed by Taylor expansion of the spacecraft position vector: Among them, R(T) is the position vector at time T, V(T) is the corresponding velocity vector, is the time derivative of the position vector.

6. The method for adaptive variable step-size simulation of aerospace system with very high time-frequency accuracy according to claim 1, characterized in that: The dynamic adjustment of the sub-clock availability in step S5 is triggered by a preset instruction, and when it is detected that the simulation step length Δt>ΔT, the sub-clock timing function is frozen, and when Δt<ΔT, the coordinated timing of the sub-clock and the main clock is reactivated.

7. The method for adaptive variable step-size simulation of aerospace system with very high time-frequency accuracy according to claim 1, characterized in that: The method further comprises: automatically enabling the sub-clock when the simulation step length requirement is at the microsecond level, and switching to the main clock independent timing mode when the simulation step length requirement is enlarged to the second level.

8. The method for adaptive variable step-size simulation of aerospace system with very high time-frequency accuracy according to claim 1, characterized in that: The method further comprises: monitoring the sub-clock accumulated time in real time during the simulation process, and automatically performing a carry operation when t reaches an integer multiple of ΔT.

9. A computer device, characterized in that: It comprises a memory and a processor, wherein the memory stores a computer program, and when the processor runs the computer program stored in the memory, the processor executes an adaptive variable-step-size simulation method for aerospace systems with very high time-frequency accuracy as described in any one of claims 1-8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, which, when executed by a processor, executes the steps of an adaptive variable-step-size simulation method for aerospace systems with very high time-frequency accuracy as described in any one of claims 1-8.

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