Real-time scheduling method and system for short-time track control resources overseas

Abstract

This invention belongs to the field of satellite telemetry, tracking, and command (TT&C) technology, and provides a method and system for real-time scheduling of short message resources during overseas orbit control. The method includes: satellite control software constructing a short message frame library and pre-configuring fixed-length normal frames and orbit control-specific frames; attitude and orbit control software monitoring orbit control status in real time, satellite control software identifying orbit control ignition commands and orbit control stage markers, and initiating a dual-queue parallel transmission mechanism; configuring the link for relay satellites according to the dual-queue parallel transmission mechanism and implementing frequency division multiplexing downlink; and entering a transition period after orbit control monitoring ends, performing periodic attenuation control on the orbit control-specific frames. This invention solves the problem of real-time status monitoring failure for geostationary orbit satellites during overseas orbit control, increasing the orbit control anomaly identification rate to over 99%, breaking through monitoring real-time limitations, and significantly improving the safety and controllability of overseas orbit control; optimizing resource utilization, enhancing adaptive capabilities, and achieving second-level on-demand downlink of key parameters and dynamic optimization of channel resources.

Description

Technical Field

[0001] This invention belongs to the field of satellite telemetry, tracking, and command (TT&C) technology. Specifically, it relates to a method and system for real-time scheduling of short message resources during overseas orbit control, and in particular, to a method for dynamic scheduling and real-time downlinking of short message resources via relay satellites when a satellite is conducting orbit control overseas. Background Technology

[0002] Satellite orbit control refers to the critical operation of adjusting satellite orbital parameters using onboard thrusters. Overseas orbit control specifically refers to the orbit control process performed when the satellite is outside the line of sight of a ground-based tracking and control station. This type of operation relies on relay satellites for status monitoring, requiring real-time transmission of critical data such as thruster operating conditions, attitude deviations, and orbital parameter increments to ensure control accuracy and safety.

[0003] Traditional satellite short message systems (such as BeiDou) use a fixed frame structure and static scheduling mechanism to achieve telemetry downlink. Their frame format is fixed, and their length is limited (BeiDou civilian frames are ≤78 bytes). Preset fields only include conventional parameters such as power supply and temperature, and cannot dynamically embed critical parameters specific to orbit control, such as thrust vector angle deviation and cathode current. The downlink cycle is rigidly set to minutes (typically 60 seconds / frame), and transmission can only proceed after channel allocation is complete, making it impossible to increase the frequency as needed. Resource allocation uses a single-queue serial mode, requiring orbit control data to queue and wait for the normal frame transmission to complete, lacking the ability to preempt service priority.

[0004] The above mechanism will expose serious flaws in overseas track control scenarios, including:

[0005] Rigid formatting leads to missing parameters: the fixed frame structure cannot accommodate track control-specific parameters. Abnormal operating conditions such as sudden cathode voltage drops lack dedicated fields for transmission, preventing the ground system from diagnosing faults in real time.

[0006] Cycle lag causes control blind spots: the minute-level downlink cycle is much slower than the second-level monitoring requirements of track control. Because downlink delays prevent timely fault handling, they lead to increased fuel consumption.

[0007] Resource preemption failures cause data backlog: The single-channel serial transmission mode results in a blockage rate of up to 73% in the orbit control data queue, which cannot meet the minimum frame interval required by the relay satellite system, creating a monitoring blind spot.

[0008] The root cause of these shortcomings lies in the fact that static frame libraries cannot adapt to dynamic service requirements, fixed periods cannot meet real-time requirements, and single-channel resources are insufficient to support concurrent multi-service operations. The patent document "Implementation Method and System of Spaceborne Integrated Electronic Short Message" (CN120301479A) discloses a method to optimize short message downlink by constructing a spaceborne integrated electronic short message framework and a ground station autonomous selection algorithm. This solves the problem of real-time communication difficulties for ground telemetry systems in short arc segments, improving satellite application efficiency and emergency response capabilities. However, this method lacks the ability to adapt to changes in different orbit control states and cannot meet dynamic service requirements.

[0009] The patent document "Dynamic Scheduling Method for Space-Time-Frequency Domain Resources of Relay Satellites for Multi-Users" (CN106507366A) discloses a dynamic scheduling method for space-time-frequency domain resources of relay satellites for multi-users. By combining latency and packet loss rate, it optimizes resource allocation and solves the problems of low spectrum utilization and unmet service requirements in multi-user scenarios, achieving efficient resource utilization and improved economic benefits. However, its core issue lies in the resource scheduling method for relay satellites, which lacks adaptability to downlink telemetry under different orbit control states.

[0010] Therefore, it is necessary to overcome the technical bottlenecks of on-demand frame content adaptation and dynamic channel allocation, and provide a real-time scheduling method for short message resources of overseas track control that can optimize resource utilization and improve real-time performance. Summary of the Invention

[0011] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method and system for real-time scheduling of short message resources during overseas track control.

[0012] A real-time scheduling method for short message resources during overseas track control, provided by the present invention, includes:

[0013] Step S1: The satellite service software constructs a short message frame library and pre-configures fixed-length normal frames and orbit control-specific frames.

[0014] Step S2: The attitude and orbit control software monitors the orbit control status in real time, and the satellite control software identifies the orbit control ignition command and orbit control stage markers, and starts the dual-queue parallel transmission mechanism.

[0015] Step S3: Configure the link for the relay satellite according to the dual-queue parallel transmission mechanism and implement frequency division multiplexing downlink;

[0016] Step S4: After the attitude and track control software finishes monitoring the track control, it enters a transition period and performs periodic decay control on the dedicated track control frames.

[0017] Preferably, in step S1, the short message module of the space service software constructs a short message frame library in the non-volatile memory of the space service computer, and pre-sets two types of fixed-length short message frame structures, including routine monitoring frames and orbit control dedicated frames.

[0018] The normal monitoring frame has a fixed length of 128 bytes and includes conventional telemetry parameters such as power supply voltage, temperature sensor data, and / or star-sensor attitude angle, which are sent according to a preset cycle.

[0019] The length of the dedicated track control frame is fixed at 128 bytes, and the field combination is automatically switched according to the three stages of track control.

[0020] Preferably, the three stages include an ignition stage short message frame library, a steady-state stage short message frame library, and a transition stage short message frame library.

[0021] During the ignition phase, the short message frame library will switch the content of the rail control-specific frame to a combination of fields such as thrust vector angle deviation, cathode voltage, and tank pressure.

[0022] During the steady-state phase, the short message frame library will switch the content of the track control dedicated frame to a combination of track semi-major axis change rate and three-axis angular velocity fields.

[0023] During the transition phase, the short message frame library will switch the content of the track control-specific frames to a combination of pitch angle error and track tilt angle deviation fields.

[0024] Preferably, in step S2, the spacecraft software continuously monitors the orbit control trigger command code. When it detects that the command code data field sent by the attitude and orbit control software to the electric propulsion controller is 0xA5A5, it is determined to be an orbit control ignition command, the dynamic scheduling module is immediately activated, and the orbit control stage is marked as the ignition stage.

[0025] The scheduling module initiates a dual-queue parallel transmission mechanism, including a high-priority queue and a low-priority queue. The high-priority queue dynamically adjusts the transmission frequency and dynamically compresses the track control-specific frames to the shortest allowable value during track control, while extending the period of normal monitoring frames.

[0026] The satellite management software injects configurable parameters through the ground telemetry and control station to set the parameters of the relay satellite.

[0027] In step S3, dual-carrier frequency division multiplexing technology is used to allocate the dedicated track control frames to the carriers of the high-priority queue and the normal monitoring frames to the carriers of the low-priority queue. The center frequency and modulation mode are determined according to the carrier type, and the field combination is switched.

[0028] Preferably, the high-priority queue adopts a hardware interrupt preemption mechanism. When the track control dedicated frame is generated, the MCU interrupt is triggered immediately, the normal detection frame transmission process is forcibly suspended, and the track control dedicated frame transmission is started within 10 milliseconds after successful preemption.

[0029] The low-priority queue will have its cycle automatically extended to three times the original cycle during track control.

[0030] The configurable parameters include the bandwidth allocation ratio of the carriers in the high-priority queue, which are stored in non-volatile memory.

[0031] The minimum allowable value is dynamically calculated based on the timing characteristics of the relay satellite link, and is not less than the minimum frame interval of 10 seconds required by the relay satellite.

[0032] Preferably, the carrier of the high-priority queue is a high-priority carrier f1, with a center frequency range of 2200.0 MHz to 2299.9 MHz, a QPSK modulation scheme, a bandwidth allocation ratio of a preset parameter Q, and is stored in on-board non-volatile memory. The transmitted content is a dedicated orbit control frame, and the period is compressed to the shortest permissible value T. min .

[0033] The carrier of the low-priority queue is low-priority carrier f2, with a center frequency range of 2200.00 MHz to 2299.99 MHz, a modulation method of BPSK, and the remaining bandwidth is allocated. The transmitted content is a normal monitoring frame.

[0034] In step S3, the short message module determines whether the track control status is in the ignition stage based on the track control stage flag. If so, it calls the ignition stage short message frame library; otherwise, it calls the steady-state stage short message frame library to determine whether it is in the transition stage.

[0035] If not, then determine again whether it is in the ignition stage. If it is, then call the transition stage short message frame library and execute step S4.

[0036] Preferably, step S4 includes:

[0037] Step S4.1: Set the initial cycle to 10 seconds;

[0038] Step S4.2: The transmission period of the dedicated track control frame gradually decreases linearly over time, and the short message frame library for the transition phase is called.

[0039] Step S4.3: Determine whether the semi-major axis deviation of the track is ≤ the set value θ. If yes, stop sending the track control special frame. If no, proceed to step S4.2.

[0040] Step S4.4: Determine whether the transmission period of the dedicated track control frame has returned to the normal value. If yes, stop the attenuation. If no, proceed to step S4.2.

[0041] Preferably, it also includes an exception handling step:

[0042] The anomaly type is determined based on the anomaly handling mechanism. When the anomaly type is a relay link interruption, the system switches to store-and-forward mode, re-establishes the link, and then retransmits the data in batches.

[0043] When the anomaly type is track control timeout, the safety mode is triggered and the fault code is transmitted, and the ground command is used to reset;

[0044] When the exception type is data verification failure, the error frame is discarded and logged, and automatically resent in the next sending cycle.

[0045] A real-time scheduling system for short message resources during overseas orbit control, provided by the present invention, includes: an electric propulsion controller, a spacecraft computer, and a CAN bus;

[0046] The spaceborne computer includes non-volatile memory, attitude and orbit control software, and spaceborne software;

[0047] The satellite communication software includes a short message module and a dynamic scheduling module;

[0048] The electric propulsion controller communicates with the spacecraft computer via a CAN bus, and the short message module builds a short message frame library in non-volatile memory.

[0049] The spacecraft software continuously monitors the CAN bus, captures and identifies the orbit control ignition command and orbit control stage marker in real time, and initiates a dual-queue parallel transmission mechanism.

[0050] The dynamic scheduling module configures the link for the relay satellite according to the dual-queue parallel transmission mechanism and implements frequency division multiplexing downlink;

[0051] After the attitude and track control software finishes monitoring the track control process, it enters a transition period and performs periodic decay control on the dedicated track control frames.

[0052] Preferably, the spacecraft computer determines the anomaly type based on the anomaly handling mechanism, takes corresponding processing measures, and determines the recovery conditions:

[0053] When the exception type is a relay link interruption, switch to store-and-forward mode, re-establish the link, and then retransmit in batches.

[0054] When the anomaly type is track control timeout, the safety mode is triggered and the fault code is transmitted, and the ground command is used to reset;

[0055] When the exception type is data verification failure, the error frame is discarded and logged, and automatically resent in the next sending cycle.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] 1. This invention solves the problem of real-time status monitoring failure caused by fixed short message format and long downlink cycle during the orbit control of geostationary orbit satellites outside the country, and realizes the on-demand downlink of key parameters at the second level and dynamic optimization of channel resources.

[0058] 2. This invention increases the transmission frequency of short message frames for track control status, and reduces the downlink delay of key track control parameters from hours (>60 minutes) to seconds (≤5 seconds), breaking through the real-time monitoring barrier and significantly improving the safety and controllability of overseas track control.

[0059] 3. This invention supports on-demand switching of track control fields throughout the entire lifecycle and dynamic bandwidth allocation, enhancing adaptive capabilities and enabling better anomaly localization. The track control anomaly identification rate is increased to over 99%, resulting in a significant improvement in safety.

[0060] 4. This invention implements frequency division multiplexing downlink through relay satellite multi-carrier channels, allocates configurable carriers with a high proportion of bandwidth to the orbit control frames, optimizes resource utilization, and achieves a relay satellite channel utilization rate of 91.7%. Attached Figure Description

[0061] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0062] Figure 1 A schematic diagram illustrating the real-time scheduling method for short message resources during overseas track control. Detailed Implementation

[0063] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0064] This invention provides a real-time scheduling method for short message resources during overseas orbit control. Addressing the blind spots in orbit control status monitoring caused by the fixed format and long transmission cycle of existing short message systems, this method solves the problem of real-time status monitoring failure during overseas orbit control of geostationary orbit satellites due to the fixed short message format and long transmission cycle. It achieves second-level on-demand transmission of key parameters and dynamic optimization of channel resources. Figure 1 For example, including:

[0065] Step S1, System Initialization Configuration: This is executed through the short message module of the satellite control software, which pre-configures fixed-length normal frames and orbit control-specific frames.

[0066] Specifically, a configurable short message frame library was constructed, and two types of fixed-length short message frame structures were pre-installed in the non-volatile memory of the spacecraft computer, including routine monitoring frames and orbit control-specific frames.

[0067] Routine monitoring frame: The length is fixed at 128 bytes, containing routine telemetry parameters such as power supply voltage, temperature sensor data, and star sensor attitude angle, and is sent according to a preset period (default 60 seconds).

[0068] Track control dedicated frame: Supports three-stage dynamic field configuration, all with a length of 128 bytes. Its field content automatically switches field combinations according to the track control stage, including key telemetry fields during track control.

[0069] During different phases of orbit control (ignition phase, steady-state phase, and transition phase), the telemetry in the short message frames is set for the key monitoring targets of different phases. During ignition, it includes thrust vector angle, cathode electrical parameters, etc.; during the transition phase, it switches to attitude and orbital parameters and automatically stops transmitting as the cycle decays. The key telemetry monitored during the ignition phase is the anode current to prevent short circuits caused by electrical sparking; the key monitoring during the steady-state phase is the thruster status; and the key monitoring during the transition phase is orbital information to determine whether orbit control is in place.

[0070] Specifically, the content of the dedicated frame field for track control includes, based on the track control stage:

[0071] Ignition stage: Thrust vector angle deviation (4 bytes), cathode voltage (2 bytes), tank pressure (2 bytes);

[0072] Steady-state phase: rate of change of the semi-major axis of the orbit (4 bytes), angular velocity of the three axes (6 bytes);

[0073] Transition phase: Attitude stability, i.e. pitch angle error (2 bytes) and orbital tilt angle deviation (4 bytes).

[0074] Based on the field combination settings for different track control stages, the system ensures the downlink of key track control status telemetry at different stages of track control, instead of transmitting some traditional, fixed platform health status telemetry at a fixed frequency.

[0075] Step S2: Real-time track control processing flow, monitoring track control status, and the spacecraft software identifies track control commands.

[0076] Specifically, the electric propulsion controller communicates with the spacecraft computer via a CAN (Controller Area Network) bus, and the attitude and orbit control software and spacecraft software run on the spacecraft computer processor.

[0077] The spacecraft software continuously monitors the orbit control trigger command codes on the CAN bus. When it detects that the data field of the command code sent to the electric propulsion controller is 0xA5A5, it determines that it is an orbit control ignition command, immediately activates the dynamic scheduling module, and marks the orbit control phase as the ignition period.

[0078] After capturing the orbit control engine ignition command (spacecraft bus command code) and orbit control stage flag in real time, the scheduling module starts a dual-queue parallel management strategy. The high-priority queue uses hardware interrupts to preempt high priority, dynamically compresses the orbit control dedicated frame to the shortest allowable period (i.e., the predetermined shortest period), and extends the period of the normal monitoring frame.

[0079] The satellite control software sets relay satellite parameters and injects configurable parameters through ground telemetry and control stations, reducing the downlink latency of key orbit control parameters from hours to seconds, significantly improving the safety and controllability of overseas orbit control.

[0080] In more preferred embodiments, a dynamic scheduling algorithm is activated. When a track control command is detected, the scheduling module initiates a dynamic scheduling mechanism that involves parallel transmission of data through dual queues. The track control dedicated frame queue has a higher priority than the normal monitoring frame queue, and the transmission frequency is dynamically adjusted. During track control operations, the period of the track control dedicated frame is compressed to a predetermined minimum period, while the period of the normal monitoring frame is extended. Specifically, this includes:

[0081] For high-priority queues: dedicated to track control frames, a hardware interrupt preemption mechanism is used. When a track control frame is generated, an MCU (microcontroller unit) interrupt (priority 7) is triggered immediately, forcibly suspending the normal frame transmission process. After successful preemption, track control frame transmission is initiated within 10 milliseconds. Because the transmission frequency of short track control status messages is increased, the real-time performance of ground-based track control status acquisition is further improved.

[0082] For low-priority queues: During routine monitoring frames, the cycle is automatically extended to three times the original cycle (i.e., 180 seconds) during track control.

[0083] Step S3: Channel resource allocation to achieve frequency division multiplexing downlink and link configuration for relay satellites.

[0084] By employing dual-carrier frequency division multiplexing (FDM) technology, FDM downlink is implemented through the multi-carrier channel of the relay satellite, allocating configurable carriers with a high proportion of bandwidth to the orbit control frames, optimizing resource utilization, and achieving a relay satellite channel utilization rate of 91.7%.

[0085] Specifically, dedicated track control frames are allocated to high-priority carrier frequencies, while normal frames are allocated to low-priority carrier frequencies. The center frequency and modulation scheme are determined based on the carrier type. This supports on-demand switching of track control fields throughout the entire lifecycle and dynamic bandwidth allocation, enhancing adaptive capabilities, including:

[0086] High-priority carrier f1: Center frequency range is 2200.0 MHz to 2299.9 MHz, modulation mode is QPSK (Quadrature Phase Shift Keying), bandwidth allocation ratio is preset parameter Q (configurable parameter that can be modified), stored in on-board non-volatile memory;

[0087] The transmitted content consists of dedicated track control frames (10 seconds / frame), with the period compressed to the shortest permissible value T. min (e.g., ≥10 seconds);

[0088] High-priority carrier bandwidth percentage: Default value 75%, adjustable within the range of 65% to 80%.

[0089] The minimum allowable value is dynamically calculated based on the timing characteristics of the relay satellite link, and is not less than the minimum frame interval required by the relay satellite. The minimum frame interval is fixed at 10 seconds, which complies with international relay satellite system specifications.

[0090] Low-priority carrier f2: Center frequency range of 2200.00 MHz to 2299.99 MHz, modulation method of BPSK (Binary Phase Shift Keying), bandwidth allocation of the remaining bandwidth, transmission content of normal monitoring frames (180 seconds / frame). The specific center frequency is extravagant.

[0091] Based on the current track control stage, select the field combination from the preset short message frame library:

[0092] Ignition stage: Read thrust vector angle, cathode voltage and tank pressure data from sensors in real time and fill them into predefined fields.

[0093] Steady-state phase: Replace the cathode voltage field with the orbital semi-major axis change rate, and retain the triaxial angular velocity field.

[0094] Transition phase: Delete all propulsion parameters and add attitude stability and trajectory deviation parameters.

[0095] Step S4, the transition period control strategy, requires periodic decay control.

[0096] After track control is completed, a transition period begins, during which the transmission cycle of track control-specific frames is gradually reduced to a normal cycle, and the frame content is dynamically replaced with attitude and track monitoring parameters. When the track parameters converge to a threshold range, the transmission of track control-specific frames is stopped.

[0097] The field combination is achieved through an on-board mapping table, which can contain a variety of predefined field configuration templates.

[0098] Specifically, after track control is completed, a linear decay algorithm is initiated, including:

[0099] Step S4.1: Maintain the initial cycle for 10 seconds.

[0100] Step S4.2: The orbit control frame period increases linearly with time to a normal value, and the frame content is dynamically migrated to the attitude / orbit monitoring parameters;

[0101] In a preferred embodiment, the cycle time is increased by 5 seconds per minute (the slope is configurable).

[0102] Step S4.3: Stop decaying when the period returns to the normal value of 60 seconds.

[0103] The rules for frame content migration follow the presets of the short message frame library: field replacement is performed during the transition phase; thruster condition-related fields are deleted; attitude stability (roll / pitch angle standard deviation) is added; and orbital semi-major axis deviation is added.

[0104] The termination condition is that when the deviation of the semi-major axis of the track is less than or equal to the set value θ, the transmission of track control special frames is stopped, and θ is preferably 10m.

[0105] In many preferred embodiments, exception handling steps are also included.

[0106] The abnormal handling steps involve determining the abnormal type based on the abnormal handling mechanism, taking corresponding handling measures, and determining the recovery conditions, thereby increasing the track control abnormality identification rate to over 99%.

[0107] Because traditional short messages have limited length and fixed content, they cannot pinpoint the cause of possible anomalies during track control. However, by building a short message frame library, anomalies can be located more effectively.

[0108] When the exception type is a relay link interruption and no ACK (acknowledgment message) is received for 3 consecutive frames, the system switches to store-and-forward mode, re-establishes the link, and retransmits the data in batches.

[0109] When the anomaly type is track control timeout, if the track control strategy fails to end within 300 seconds after the set end time, the safety mode is triggered and a fault code is transmitted, and the ground command is used to reset;

[0110] When the exception type is data verification failure, the error frame is discarded and logged, and automatically resent in the next cycle.

[0111] This invention also provides a real-time scheduling system for short message resources during overseas orbit control, comprising: an electric propulsion controller, a spacecraft computer, and CAN bus communication;

[0112] The spaceborne computer includes non-volatile memory, attitude and orbit control software, and spaceborne software;

[0113] The satellite communication software includes a short message module and a dynamic scheduling module.

[0114] The electric propulsion controller communicates with the spacecraft computer via a CAN bus, and the short message module builds a short message frame library in non-volatile memory.

[0115] The spacecraft software continuously monitors the CAN bus, captures and identifies the orbit control ignition command and orbit control stage marker in real time, and initiates a dual-queue parallel transmission mechanism.

[0116] The dynamic scheduling module configures the link for the relay satellite according to the dual-queue parallel transmission mechanism and implements frequency division multiplexing downlink;

[0117] After the attitude and track control software finishes monitoring the track control process, it enters a transition period and performs periodic decay control on the dedicated track control frames.

[0118] In more preferred examples, the spaceborne computer determines the anomaly type based on the anomaly handling mechanism, takes corresponding processing measures, and determines the recovery conditions:

[0119] When the exception type is a relay link interruption, switch to store-and-forward mode, re-establish the link, and then retransmit in batches.

[0120] When the anomaly type is track control timeout, the safety mode is triggered and the fault code is transmitted, and the ground command is used to reset;

[0121] When the exception type is data verification failure, the error frame is discarded and logged, and automatically resent in the next sending cycle.

[0122] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method for real-time scheduling of short message resources for overseas track control, characterized in that, include: Step S1: The satellite service software constructs a short message frame library and pre-configures fixed-length normal frames and orbit control-specific frames. Step S2: The attitude and orbit control software monitors the orbit control status in real time, and the satellite control software identifies the orbit control ignition command and orbit control stage markers, and starts the dual-queue parallel transmission mechanism. Step S3: Configure the link for the relay satellite according to the dual-queue parallel transmission mechanism and implement frequency division multiplexing downlink; Step S4: After the attitude and track control software finishes monitoring the track control, it enters a transition period and performs periodic decay control on the dedicated track control frames. The length of the dedicated track control frame is fixed at 128 bytes, and the field combination is automatically switched according to the three stages of track control. The three phases include the short message frame library for the ignition phase, the short message frame library for the steady-state phase, and the short message frame library for the transition phase. During the ignition phase, the short message frame library will switch the content of the rail control-specific frame to a combination of fields such as thrust vector angle deviation, cathode voltage, and tank pressure. During the steady-state phase, the short message frame library will switch the content of the track control dedicated frame to a combination of track semi-major axis change rate and three-axis angular velocity fields. During the transition phase, the short message frame library will switch the content of the track control dedicated frame to a combination of pitch angle error and track tilt angle deviation fields. In step S2, the spacecraft software continuously monitors the orbit control trigger command code. When it detects that the command code data field sent by the attitude and orbit control software to the electric propulsion controller is 0xA5A5, it determines that it is an orbit control ignition command, immediately activates the dynamic scheduling module, and marks the orbit control stage as the ignition stage. The scheduling module initiates a dual-queue parallel transmission mechanism, including a high-priority queue and a low-priority queue. The high-priority queue dynamically adjusts the transmission frequency and dynamically compresses the track control-specific frames to the shortest allowable value during track control, while extending the period of normal monitoring frames. The satellite control software injects configurable parameters through the ground telemetry and control station to set the parameters of the relay satellite; In step S3, dual-carrier frequency division multiplexing technology is used to allocate the dedicated track control frames to the carriers of the high-priority queue and the normal monitoring frames to the carriers of the low-priority queue. The center frequency and modulation mode are determined according to the carrier type, and the field combination is switched.

2. The method for real-time scheduling of short message resources for overseas track control as described in claim 1, characterized in that, In step S1, the short message module of the space service software builds a short message frame library in the non-volatile memory of the space service computer and pre-sets two types of fixed-length short message frame structures, including normal monitoring frames and orbit control dedicated frames. The normal monitoring frame has a fixed length of 128 bytes and includes conventional telemetry parameters such as power supply voltage, temperature sensor data, and / or star-sensor attitude angle, which are sent according to a preset cycle.

3. The method for real-time scheduling of short message resources for overseas track control as described in claim 1, characterized in that, The high-priority queue adopts a hardware interrupt preemption mechanism for sending rights. When the track control special frame is generated, the MCU interrupt is triggered immediately to forcibly suspend the normal detection frame sending process. After successful preemption, the track control special frame sending is started within 10 milliseconds. The low-priority queue will have its cycle automatically extended to three times the original cycle during track control. The configurable parameters include the bandwidth allocation ratio of the carriers in the high-priority queue, which is stored in non-volatile memory; The minimum allowable value is dynamically calculated based on the timing characteristics of the relay satellite link, and is not less than the minimum frame interval of 10 seconds required by the relay satellite.

4. The method for real-time scheduling of short message resources for overseas track control as described in claim 1, characterized in that, The carrier of the high-priority queue is a high-priority carrier f1, with a center frequency range of 2200.0 MHz to 2299.9 MHz, a QPSK modulation scheme, and a bandwidth allocation ratio of a preset parameter Q. It is stored in on-board non-volatile memory, and the transmitted content is a dedicated orbit control frame with its period compressed to the shortest permissible value T. min ; The carrier of the low-priority queue is low-priority carrier f2, with a center frequency range of 2200.00 MHz to 2299.99 MHz, a modulation method of BPSK, and the remaining bandwidth is allocated. The transmitted content is a normal monitoring frame. In step S3, the short message module determines whether the track control status is in the ignition stage based on the track control stage flag. If so, it calls the ignition stage short message frame library; otherwise, it calls the steady-state stage short message frame library to determine whether it is in the transition stage. If not, then determine again whether it is in the ignition stage. If it is, then call the transition stage short message frame library and execute step S4.

5. The method for real-time scheduling of short message resources for overseas track control as described in claim 1, characterized in that, Step S4 includes: Step S4.1: Set the initial cycle to 10 seconds; Step S4.2: The transmission period of the dedicated track control frame gradually decreases linearly over time, and the short message frame library for the transition phase is called. Step S4.3: Determine whether the semi-major axis deviation of the track is ≤ the set value θ. If yes, stop sending the track control special frame. If no, proceed to step S4.

2. Step S4.4: Determine whether the transmission period of the dedicated track control frame has returned to the normal value. If yes, stop the attenuation. If no, proceed to step S4.

2.

6. The method for real-time scheduling of short message resources for overseas track control as described in claim 1, characterized in that, It also includes exception handling steps: The anomaly type is determined based on the anomaly handling mechanism. When the anomaly type is a relay link interruption, the system switches to store-and-forward mode, re-establishes the link, and then retransmits the data in batches. When the anomaly type is track control timeout, the safety mode is triggered and the fault code is transmitted, and the ground command is used to reset; When the exception type is data verification failure, the error frame is discarded and logged, and automatically resent in the next sending cycle.

7. A real-time scheduling system for short-message resources in overseas track control systems, characterized in that, include: Electric propulsion controller, spacecraft computer, and CAN bus; The spaceborne computer includes non-volatile memory, attitude and orbit control software, and spaceborne software; The satellite communication software includes a short message module and a dynamic scheduling module; The electric propulsion controller communicates with the spacecraft computer via a CAN bus, and the short message module builds a short message frame library in non-volatile memory. The spacecraft software continuously monitors the CAN bus, captures and identifies the orbit control ignition command and orbit control stage marker in real time, and initiates a dual-queue parallel transmission mechanism. The dynamic scheduling module configures the link for the relay satellite according to the dual-queue parallel transmission mechanism and implements frequency division multiplexing downlink; After the attitude and track control software finishes monitoring the track control process, it enters a transition period and performs periodic decay control on the dedicated track control frames. The length of the dedicated track control frame is fixed at 128 bytes, and the field combination is automatically switched according to the three stages of track control. The three phases include the short message frame library for the ignition phase, the short message frame library for the steady-state phase, and the short message frame library for the transition phase. During the ignition phase, the short message frame library will switch the content of the rail control-specific frame to a combination of fields such as thrust vector angle deviation, cathode voltage, and tank pressure. During the steady-state phase, the short message frame library will switch the content of the track control dedicated frame to a combination of track semi-major axis change rate and three-axis angular velocity fields. During the transition phase, the short message frame library will switch the content of the track control dedicated frame to a combination of pitch angle error and track tilt angle deviation fields. The spacecraft software continuously monitors the orbit control trigger command code. When it detects that the command code data field sent by the attitude and orbit control software to the electric propulsion controller is 0xA5A5, it determines that it is an orbit control ignition command, immediately activates the dynamic scheduling module, and marks the orbit control stage as the ignition stage. The scheduling module initiates a dual-queue parallel transmission mechanism, including a high-priority queue and a low-priority queue. The high-priority queue dynamically adjusts the transmission frequency and dynamically compresses the track control-specific frames to the shortest allowable value during track control, while extending the period of normal monitoring frames. The satellite control software injects configurable parameters through the ground telemetry and control station to set the parameters of the relay satellite; The dual-carrier frequency division multiplexing technology is adopted to allocate the dedicated track control frames to the carriers of the high-priority queue and the routine monitoring frames to the carriers of the low-priority queue. The center frequency and modulation mode are determined according to the carrier type, and the field combination is switched.

8. The real-time scheduling system for short message resources for overseas track control as described in claim 7, characterized in that, The spaceborne computer determines the anomaly type based on the anomaly handling mechanism, takes corresponding processing measures, and determines the recovery conditions: When the exception type is a relay link interruption, switch to store-and-forward mode, re-establish the link, and then retransmit in batches. When the anomaly type is track control timeout, the safety mode is triggered and the fault code is transmitted, and the ground command is used to reset; When the exception type is data verification failure, the error frame is discarded and logged, and automatically resent in the next sending cycle.

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