Disclosure of Invention
The invention provides an on-orbit virtualization method of space-based resources based on available capacity calculation aiming at the requirements of a large-scale satellite network for providing global instant information service for users and unified management and cooperative application of various heterogeneous satellites, and provides uniformly-described, high-timeliness and credible space-based resources for the users. The method comprises the steps of carrying out attribute analysis facing a user service capability layer aiming at various observation loads, calculation loads and communication equipment, abstracting three space-based resource capabilities, carrying out on-orbit real-time calculation by integrating time, space, energy, storage, load attributes and existing task constraints, constructing a standardized space-based resource available capability list, realizing unified management of various heterogeneous satellites, and enabling users to put forward requirements without knowing specific satellite technologies and related attribute parameters. Meanwhile, the rapid response of the satellite to the user requirement is realized by fully using modes of pre-calculation, master-slave satellite calculation load balancing and the like, and the timeliness of multi-satellite cooperative application is ensured.
In order to achieve the above object, the present invention provides an on-orbit virtualization method for space-based resources based on available capacity calculation, which is used for calculating available capacity of space-based resources of a single-satellite or multi-satellite cooperative task, and the method includes:
the available capacity of the current satellite is divided into three categories: information observation capability, information processing capability and information transmission capability;
calculating a list of available observation space-time bands of all the observation loads;
calculating available data processing duration lists of all processing loads;
and calculating the available time period list of the transmission capability of all the transmission and distribution devices.
As an improvement of the above method, the step of calculating the list of available observation spatiotemporal stripes for all observation loads comprises:
before a task demand arrives, basic data are calculated, wherein the basic data comprise a solar altitude angle, a shadow area sun exposure area, observation coverage visibility, ground coverage, area coverage time, a satellite orbit and an attitude;
calculating task constraints based on basic data, wherein the task constraints comprise distributable storage capacity, distributable energy, an available observation time interval and a maximum observation time length;
calculating user requirements, matching the requirements and authorities of users in a specific space-time interval, and determining the observation coverage range, task observation time interval, load imaging resolution, breadth and spectral band attributes of each observation load, thereby forming an available observation space-time band list.
As an improvement of the above method, if the observed load is a non-visible light load, the step of calculating the area coverage time includes:
selecting all working time periods of the current observed load;
inquiring satellite ephemeris data for each working period;
calculating satellite transit coverage data for each working time period, and recording coverage point pairs at each moment;
forming a coverage area by two continuous coverage point pairs at a specific time, and calculating observation coverage visibility according to the intersection condition of the coverage area and a target area; if the coverage area and the target area are not intersected all the time, the observation coverage is invisible; otherwise, recording the intersection starting time as the transit starting time, and recording the intersection ending time as the transit ending time as a transit time interval, wherein the transit time interval is the area coverage time;
and forming a regional target transit time interval list by all the transit time intervals.
As an improvement of the above method, if the observed load is a visible light load, the step of calculating the area coverage time includes:
selecting all working time periods of the current observed load;
inquiring satellite ephemeris data for each working period;
calculating satellite transit coverage data for each working time period, and recording coverage point pairs at each moment;
calculating time intervals of shadow areas and sunshine areas of the satellites;
if the specific time is located in the sunshine area time interval, the solar altitude is continuously calculated; if the altitude angle meets the observation load constraint condition, forming a coverage area by two continuous coverage point pairs at a specific moment, and calculating observation coverage visibility according to the intersection condition of the coverage area and the target area; if the coverage area and the target area are not intersected all the time, the observation coverage is invisible; otherwise, recording the intersection starting time as the transit starting time, and recording the intersection ending time as the transit ending time as a transit time interval; the transit time interval is the area coverage time;
if the specific time is positioned in the shadow region time interval or the solar altitude angle does not meet the observation load constraint condition, the observation coverage is always invisible; and forming a regional target transit time interval list by all the transit time intervals.
As an improvement of the above method, the step of calculating the issuable storage capacity specifically includes:
according to the planned task list, calculating the observation data volume and the transmission data volume of each task, and calculating the consumption storage capacity of each task; wherein, the storage occupation is increased by generating observation data, and the storage occupation is relieved by downloading the data;
storing the consumed storage capacity of all tasks according to the task starting time to generate a consumed storage capacity list;
calculating a remaining storage capacity list which is the difference value between the initial capacity of the satellite mass storage module and each item of consumed storage capacity;
and reading in a residual storage capacity list, traversing the list, and taking the minimum value as the distributable storage capacity.
As an improvement of the above method, the step of calculating the issuable energy source specifically includes:
predicting the energy consumption condition of the storage battery according to the scheduled tasks, reading the initial capacity of the storage battery and the scheduled task list, and calculating the energy consumption difference delta e (i) in the period i in each charging and discharging period:
Δe(i)=e(i)-e(i-1)
e (i), wherein e (i-1) is the charge and discharge amount of the satellite in the ith and i-1 operating periods respectively;
the issuable energy source E (i) of the period i is:
E0,E1respectively the initial electric quantity and the maximum discharge depth of the storage battery.
As an improvement of the above method, the step of calculating the available observation time interval specifically includes:
calculating a satellite transit time interval;
and inquiring the idle time list in the transit time interval, and calculating the satellite idle time interval as an available observation time interval.
As an improvement of the above method, the step of calculating the maximum observation time specifically includes:
calculate the maximum observable length constrained by issuable storage capacity:
T1=K1·S
wherein, T1For maximum observable time constrained by issuable storage capacity, S is issuable storage capacity, K1The weight is related to the type of the observed load and the working mode thereof;
calculating the maximum maneuvering energy consumption of the satellite observation task;
calculating energy consumption which can be used for observing tasks, wherein the calculation method comprises the following steps:
Eo=E(i)-2*fa
wherein E is0To observe the energy consumption of a task, E (i) is the issuable energy in a time interval i, faMaximum maneuvering consumption for satellite observation tasks;
calculating the maximum observable time length constrained by the issuable energy, wherein the calculation method comprises the following steps:
T2=E0/e0
wherein, T2For the maximum observable time constrained by the issuable energy, e0Energy consumption per unit time for observing the load;
the maximum observable time duration is the minimum of the maximum observable time duration constrained by the issuable storage capacity and the maximum observable time duration constrained by the issuable energy.
As an improvement of the above method, the calculation step of the observation coverage is:
calculating satellite ephemeris data of all the area coverage time; then calculating satellite transit coverage data and recording coverage point pairs at each moment; and combining the coverage point pairs into a coverage area to form an observation coverage range.
As an improvement of the above method, the step of calculating the task observation time interval includes:
calculating the intersection of all available observation time intervals and the time intervals of the area coverage time to form a time interval list; and calculating the maximum observation time length in each time interval of the list types to form a task observation time interval.
As an improvement of the foregoing method, the calculating the available data processing duration list of all processing loads specifically includes:
calculating task constraints, wherein the task constraints comprise distributable storage capacity, distributable energy, an available processing time interval and a maximum processing time;
and matching according to the requirements and the authority of the user in a specific time-space interval, wherein the matching comprises the steps of determining the processing task time of each processing load, reading the data type to be processed and the load CPU type attribute, calculating the processing data volume, and forming an available data processing time length list by the processing task time, the processing data volume, the data processing type and the load CPU type of each processing load.
As an improvement of the above method, the step of calculating the available processing time interval comprises:
determining user priority;
for a specific satellite, determining that the priority of a task list of the specific satellite is lower than the priority of a current user, and the task type is an occupied time interval for processing a task;
calculating a processing task space time interval according to the occupied time interval to form a processing task free time interval list;
for each idle time interval in the idle time interval list of the processing task, calculating the starting time of the available processing time interval, wherein the calculating method comprises the following steps:
L1=Ls+Lp
wherein L is1Is the start time of the available processing time interval, LsIs the start time of the idle time interval, LpPreparing time for processing load starting;
the end time of the available processing time interval is the end time of the idle time interval, and the start time of the available processing time interval constitutes the available processing time interval.
As an improvement of the above method, the step of calculating the maximum processing time period includes:
calculating distributable energy Ef;
Calculating the maximum processing time constrained by the issuable energy, wherein the calculation method comprises the following steps:
L2=Ef/e0-Lp
wherein L is2Maximum processing duration constrained by issuable energy, e0Energy consumption per unit time to handle the load, LpIs prepared byLoad boot time is handled.
As an improvement of the above method, the step of calculating the processing task time includes:
acquiring issuable energy of a starting time in each available processing time interval;
for each available processing time interval, calculating the maximum processing time length in the interval according to the issuable energy;
calculating the processing task time taking the available processing time interval as the maximum time range and taking the maximum processing time interval as the selectable interval;
reading the attributes of the data type to be processed and the load CPU type to calculate the processing data amount, specifically:
D=K2·L
wherein D is the amount of data to be processed, L is the processing task time of the load, K2The weight value is related to the type of data to be processed and the CPU property of the processing load.
As an improvement of the above method, the step of calculating the transmission capability available period list of all the transmission and distribution devices includes:
calculating basic data before a task demand arrives, wherein the basic data comprises an inter-satellite link connection list and a satellite attitude;
calculating task constraints, wherein the task constraints comprise distributable storage capacity, distributable energy, an available transmission time interval and a maximum transmission time;
calculating user requirements, matching the requirements and authorities of users in a specific time-space interval, determining transmission task time and data volume of each transmission and distribution device, and forming a transmission capacity available time period list.
As an improvement of the above method, the step of calculating the inter-satellite link connection list includes:
calculating the position information of the satellite at the corresponding moment;
calculating the inter-satellite distance between two satellites at each moment, and when the inter-satellite distance is within a communicable distance range related to inter-satellite link adoption equipment, the inter-satellite links are communicated;
calculating the trend of the inter-satellite link connectivity changing along with time when each satellite establishes links with other satellites, and recording the trend as a connection interval;
and all the connected intervals form an inter-satellite link connected list.
As an improvement of the above method, the step of calculating the available transmission time interval comprises:
calculating an inter-satellite link communication interval, and acquiring a transmittable time interval of the laser load;
determining user priority;
for a specific satellite, determining the task list of the specific satellite, wherein the task list is lower than the priority of a current user, and the task type is a transmission task or an occupied time interval of tasks related to the satellite attitude;
calculating a transmission task space time interval according to the occupied time interval to form a processing task idle time interval list;
calculating an available time interval list of laser transmission, wherein the available time interval list is an intersection of a laser transmittable time interval and an idle time interval;
for each time interval in the list of available time intervals for laser transmission, the method for calculating the starting time of the laser-transmittable time interval comprises the following steps:
Tlt=Ls+Tm+TT
wherein, TltIs the start time of the laser transmissible time interval, LsIs the start time of the idle time interval, TmFor maximum satellite maneuver time, TtThe laser tracking time;
the end time of the laser transmittable time interval is the end time of the idle time interval, and the start time of the laser transmittable time interval constitutes an available transmission time interval.
As an improvement of the above method, the step of calculating the maximum transmission time period includes:
for transmitting a transmitting satellite and a receiving satellite, calculating the consumption of available energy for laser transmission, wherein the calculation method comprises the following steps:
El=Ef-Ect-Esp
wherein E islEnergy consumption available for laser transmission, EfFor releasing energy, EctFor coarse adjustment of the maximum energy consumption by laser, EspThe maximum energy consumption is oriented to the day;
calculating the maximum transmission time length of the transmission sending satellite constrained by the available energy consumption of laser transmission, wherein the calculation method comprises the following steps:
TLm=El/Ek
wherein, TLmFor maximum transmission duration, ElFor laser transmission energy consumption, EkIs the energy consumption per unit time of the laser load.
For the receiving satellite, the maximum transmission duration constrained by the issuable storage capacity is calculated:
T2=K2·S
wherein, T2For maximum transmission duration constrained by issuable storage capacity, S is issuable storage capacity, K2The weight value is related to the type of the transmission load and the working mode thereof;
the maximum transmission duration of the transmitting and receiving satellite is the minimum of the maximum transmission duration constrained by the issuable storage capacity and the maximum transmission duration constrained by the issuable energy.
As an improvement of the above method, the step of calculating the transmission task time of the load comprises:
according to the inter-satellite link connection list, calculating the available transmission time interval of each pair of connectable satellites;
calculating the intersection of the connected time interval of each pair of connectable satellites and the available transmission time intervals of the two satellites;
and respectively calculating the maximum transmission time length of the two satellites in the intersection time interval to form a transmission task time taking the time interval as the maximum time range and taking the maximum transmission time interval as an optional interval.
As an improvement of the above method, the step of calculating the distribution task time includes:
calculating the available transmission time interval of each connectable satellite according to the satellite-ground link connection list;
calculating the intersection of the connected time interval of each connectable satellite and the available transmission time interval of the satellite;
and calculating the maximum transmission time length of the satellite in the intersection time interval to form a distribution task time taking the time interval as the maximum time range and taking the maximum transmission time interval as an optional interval.
The invention has the advantages that:
1. the invention provides an on-orbit virtualization method of space-based resources based on available capacity calculation, which is characterized in that abstract attribute analysis facing to the user service capacity level is carried out aiming at various observed loads, calculated loads and communication equipment, multiple types of heterogeneous space-based resources are abstracted into three space-based resource capacities, the strong coupling constraint characteristic of the resources is considered, and decoupling between functions and hardware is carried out; the high space-time dynamic characteristics of space-based resources are fully considered through an on-orbit real-time calculation algorithm, and the timeliness and the availability of space-based resource virtualization are guaranteed;
2. by using the virtualization method, various observation loads, calculation loads and communication equipment can be unified and virtualized into three space-based resource capacities, a standardized space-based resource available capacity list description method is provided, and the unified management and collaborative application requirements of various heterogeneous satellites are met; in addition, because the space-based resource abstract analysis and description facing to the user service capability level are used, the understanding and the use of the user are facilitated, and the open use of the space-based resource to the common public can be supported; meanwhile, the on-orbit real-time computing algorithm can support the instant message service response of the user by fully using modes of pre-computing, master-slave satellite computing load balancing and the like, and basically meets the requirement of an emergency task with high instantaneity.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings.
As shown in fig. 1, the present invention provides an on-orbit virtualization method for space-based resources based on available capacity calculation, which is used for calculating available capacity of space-based resources of a single-satellite or multi-satellite cooperative task, and the method includes:
step 1) the available capacity of the current satellite is divided into three categories: information observation capability, information processing capability and information transmission capability;
step 2) calculating available observation space-time stripe lists of all observation loads; the method specifically comprises the following steps:
step 2-1) calculating basic data before a task requirement is reached, wherein the basic data comprises a solar altitude angle, a shadow area sun-exposed area, observation coverage visibility, ground coverage, area coverage time, a satellite orbit and an attitude;
if the observed load is a non-visible light load, the step of calculating the area coverage time comprises:
selecting all working time periods of the current observed load;
inquiring satellite ephemeris data for each working period;
calculating satellite transit coverage data for each working time period, and recording coverage point pairs at each moment;
and forming a coverage area by two continuous coverage point pairs at a specific time, and calculating the observation coverage visibility according to the intersection condition of the coverage area and the target area. If the coverage area and the target area are not intersected all the time, the observation coverage is invisible; if the two are intersected, the intersection starting time is recorded as the transit starting time, the intersection ending time is recorded as the transit ending time, and the transit time interval is the area coverage time;
and forming a regional target transit time interval list by all the transit time intervals.
If the observed load is a visible light load, the step of calculating the area coverage time comprises:
selecting all working time periods of the current observed load;
inquiring satellite ephemeris data for each working period;
calculating satellite transit coverage data for each working time period, and recording coverage point pairs at each moment;
calculating time intervals of shadow areas and sunshine areas of the satellites;
if the specific time is located in the sunshine area time interval, the solar altitude is continuously calculated; and if the altitude angle meets the observation load constraint condition, combining two continuous coverage point pairs at a specific moment into a coverage area, and calculating the observation coverage visibility according to the intersection condition of the coverage area and the target area. If the coverage area and the target area are not intersected all the time, the observation coverage is invisible; if the two are intersected, recording the intersection starting time as the transit starting time, and recording the intersection ending time as the transit ending time as a transit time interval; the transit time interval is the area coverage time;
if the specific time is positioned in the shadow region time interval or the solar altitude angle does not meet the observation load constraint condition, the observation coverage is always invisible; and forming a regional target transit time interval list by all the transit time intervals.
Step 2-2) calculating task constraints based on basic data, wherein the task constraints comprise distributable storage capacity, distributable energy, an available observation time interval and maximum observation duration;
step 2-2-1) calculating the distributable storage capacity, which specifically comprises the following steps:
according to the planned task list, calculating the observation data volume and the transmission data volume of each task, and calculating the consumption storage capacity of each task; wherein, the storage occupation is increased by generating observation data, and the storage occupation is relieved by downloading the data;
storing the consumed storage capacity of all tasks according to the task starting time to generate a consumed storage capacity list;
calculating a remaining storage capacity list which is the difference value between the initial capacity of the satellite mass storage module and each item of consumed storage capacity;
and reading in a residual storage capacity list, traversing the list, and taking the minimum value as the distributable storage capacity.
Step 2-2-2) calculating the distributable energy, which specifically comprises the following steps:
predicting the energy consumption condition of the storage battery according to the scheduled tasks, reading the initial capacity of the storage battery and the scheduled task list, and calculating the energy consumption difference delta e (i) in the period i in each charging and discharging period:
Δe(i)=e(i)-e(i-1)
e (i), wherein e (i-1) is the charge and discharge amount of the satellite in the ith and i-1 operating periods respectively;
the issuable energy source E (i) of the period i is:
E0,E1respectively the initial electric quantity and the maximum discharge depth of the storage battery.
Step 2-2-3) calculating an available observation time interval, which specifically comprises the following steps:
calculating a satellite transit time interval;
and inquiring the idle time list in the transit time interval, and calculating the satellite idle time interval as an available observation time interval.
Step 2-2-4) calculating the maximum observation time, which specifically comprises the following steps:
calculate the maximum observable length constrained by issuable storage capacity:
T1=K1·S
wherein, T1For maximum observable time constrained by issuable storage capacity, S is issuable storage capacity, K1The weight is related to the type of the observed load and the working mode thereof;
calculating the maximum maneuvering energy consumption of the satellite observation task;
calculating energy consumption which can be used for observing tasks, wherein the calculation method comprises the following steps:
Eo=E(i)-2*fa
wherein E is0To observe the energy consumption of a task, E (i) is the issuable energy in a time interval i, faMaximum maneuvering consumption for satellite observation tasks;
calculating the maximum observable time length constrained by the issuable energy, wherein the calculation method comprises the following steps:
T2=E0/e0
wherein, T2For the maximum observable time constrained by the issuable energy, e0Energy consumption per unit time for observing the load;
the maximum observable time duration is the minimum of the maximum observable time duration constrained by the issuable storage capacity and the maximum observable time duration constrained by the issuable energy.
And 2-3) calculating user requirements, matching the requirements and the authorities of the users in a specific space-time interval, and determining the observation coverage range, the observation task time, the load imaging resolution, the breadth and the spectrum attribute of each observation load so as to form an available observation space-time strip list.
The calculation steps of the observation coverage range are as follows:
calculating satellite ephemeris data of all the area coverage time; then calculating satellite transit coverage data and recording coverage point pairs at each moment; combining the coverage point pairs into a coverage area to form an observation coverage range;
the task observation time interval calculation method comprises the following steps:
calculating the intersection of all available observation time intervals and the time intervals of the area coverage time to form a time interval list; and calculating the maximum observation time length in each time interval of the list types to form a task observation time interval.
Step 3) calculating available data processing duration lists of all processing loads; the method specifically comprises the following steps:
step 3-1), calculating task constraints, wherein the task constraints comprise distributable storage capacity, distributable energy, an available processing time interval and maximum processing time;
step 3-1-1) calculating an available processing time interval, which specifically comprises the following steps:
determining user priority;
for a specific satellite, determining that the task list of the specific satellite meets the priority of a current user, and the task type is an occupied time interval for processing a task;
calculating a processing task space time interval according to the occupied time interval to form a processing task free time interval list;
for each idle time interval in the idle time interval list of the processing task, calculating the starting time of the available processing time interval, wherein the calculating method comprises the following steps:
L1=Ls+Lp
wherein L is1Is the start time of the available processing time interval, LsIs the start time of the idle time interval, LpPreparing time for processing load starting;
the end time of the available processing time interval is the end time of the idle time interval, and the start time of the available processing time interval constitutes the available processing time interval.
Step 3-1-2) calculating the maximum processing time, which specifically comprises the following steps:
calculating distributable energy Ef;
Calculating the maximum processing time constrained by the issuable energy, wherein the calculation method comprises the following steps:
L2=Ef/e0-Lp
wherein L is2Maximum processing duration constrained by issuable energy, e0Energy consumption per unit time to handle the load, LpLoad boot time for processing.
Step 3-2) matching according to the requirements and the authorities of the users in a specific time-space interval, including determining the processing task time of each processing load, reading the data type to be processed, calculating the processing data amount according to the data type, and forming an available data processing time length list by the processing task time, the processing data amount and the data processing type of each processing load;
the step of calculating the processing task time comprises the following steps:
acquiring issuable energy of a starting time in each available processing time interval;
for each available processing time interval, calculating the maximum processing time length in the interval according to the issuable energy;
calculating the processing task time taking the available processing time interval as the maximum time range and taking the maximum processing time interval as the selectable interval;
reading the attributes of the data type to be processed and the load CPU type to calculate the processing data amount, specifically:
D=K2·L
wherein D is the amount of data to be processed, L is the processing task time of the load, K2The weight value is related to the type of data to be processed and the CPU property of the processing load.
Step 4) the step of calculating the transmission capability available period list of all the transmission and distribution devices comprises the following steps:
step 4-1) calculating basic data before the task requirement arrives, wherein the basic data comprises an inter-satellite link communication list and a satellite attitude;
the calculation step of the inter-satellite link connection list comprises the following steps:
calculating the position information of the satellite at the corresponding moment;
calculating the inter-satellite distance between two satellites at each moment, and when the inter-satellite distance is less than 1500 kilometers, connecting inter-satellite links;
calculating the trend of the inter-satellite link connectivity changing along with time when each satellite establishes links with other satellites, and recording the trend as a connection interval;
and all the connected intervals form an inter-satellite link connected list.
Step 4-2), calculating task constraints, wherein the task constraints comprise distributable storage capacity, distributable energy, an available transmission time interval and maximum transmission time;
step 4-2-1) of calculating an available transmission time interval specifically comprises the following steps:
calculating an inter-satellite link communication interval, and acquiring a transmittable time interval of the laser load;
determining user priority;
for a specific satellite, determining that the task list of the specific satellite meets the priority of a current user, and the task type is an occupied time interval for transmitting a task;
calculating a transmission task space time interval according to the occupied time interval to form a processing task idle time interval list;
calculating an available time interval list of laser transmission, wherein the available time interval list is an intersection of a laser transmittable time interval and an idle time interval;
for each time interval in the list of available time intervals for laser transmission, the method for calculating the starting time of the laser-transmittable time interval comprises the following steps:
Tlt=Ls+Tm+TT
wherein, TltIs the start time of the laser transmissible time interval, LsIs the start time of the idle time interval, TmFor maximum satellite maneuver time, TtThe laser tracking time;
the end time of the laser transmittable time interval is the end time of the idle time interval, and the start time of the laser transmittable time interval constitutes an available transmission time interval.
Step 4-2-2) calculating the maximum transmission time, which specifically comprises the following steps:
calculating the consumption of available energy for laser transmission, wherein the calculation method comprises the following steps:
El=Ef-Ect-Esp
wherein E islEnergy consumption available for laser transmission, EfFor releasing energy, EctFor coarse adjustment of the maximum energy consumption by laser, EspThe maximum energy consumption is oriented to the day;
calculating the maximum transmission time length constrained by the available energy consumption of laser transmission, wherein the calculation method comprises the following steps:
TLm=El/Ek
wherein, TLmFor maximum transmission duration, ElFor laser transmission energy consumption, EkEnergy consumption per unit time for laser loading。
And 4-3) calculating user requirements, matching the requirements and the authorities of the users in a specific time-space interval, determining the transmission task time and the data volume of each transmission and distribution device, and forming a transmission capacity available time period list.
The step of calculating the transmission task time of the load comprises the following steps:
according to the inter-satellite link connection list, calculating the available transmission time interval of each pair of connectable satellites;
calculating the intersection of the connected time interval of each pair of connectable satellites and the available transmission time intervals of the two satellites;
respectively calculating the maximum transmission time length of two satellites in the intersection time interval to form a transmission task time taking the time interval as the maximum time range and taking the maximum transmission time interval as an optional interval;
the step of calculating the distribution task time comprises the following steps:
calculating the available transmission time interval of each connectable satellite according to the satellite-ground link connection list;
calculating the intersection of the connected time interval of each connectable satellite and the available transmission time interval of the satellite;
and calculating the maximum transmission time length of the satellite in the intersection time interval to form a distribution task time taking the time interval as the maximum time range and taking the maximum transmission time interval as an optional interval.
Step 5) in the available capacity calculation process, load balancing needs to be performed on the calculation flows in the step 2), the step 3) and the step 4) so as to achieve the purpose of on-orbit virtualization of space-based resources into services, and the space-based resources are divided into two parts from the space dimension and the time dimension:
step 5-1), considering the calculation and storage constraints of the on-orbit load, and planning an on-orbit virtualization mode of a space dimension as follows:
1) the method comprises the following steps that a main satellite independent computing mode is suitable for the situation that the main satellite has strong computing capability and the data size of a task list is small;
2) the method comprises the following steps that a master satellite calculation mode and a slave satellite sharing calculation mode are adopted, wherein the mode is suitable for the situation that the slave satellite has certain calculation capacity and the data volume of a task list is large;
3) a satellite-ground cooperative computing mode which is suitable for the condition that the data volume of a task list is extremely large;
step 5-2) considering the calculation and storage constraints of the on-orbit load, the on-orbit virtualization flow strategy of the time dimension is as follows:
1) the single satellite advanced computing strategy is used for reducing the computing load of the satellite in the process of processing the task immediately by pre-computing the satellite basic characteristic data irrelevant to the current task requirement;
2) a primary satellite election strategy, namely selecting a primary satellite with the strongest computing power and calculating the main task planning part;
3) and the satellite demand allocation strategy allocates different types of virtual computing tasks according to the difference of observation, processing and transmission capabilities of different satellites.
The invention provides an on-orbit virtualization method of space-based resources based on available capacity calculation, which has the following three innovation points:
1. user demand driven: according to the method, from the perspective that a user acquires required information by using the space-based resources, the space-based resources are hierarchically, abstractly and virtualizedly formed into the service capability facing the user according to space-time logic, so that the attribute parameters of the space-based resources are transparent to the user, the user can be helped to quickly match the appropriate space-based resources, the dynamic concurrent user requirements are met, and the dynamic allocation of the space-based resources is realized;
2. on-orbit timeliness: all algorithms provided by the invention can be realized on orbit, namely, the computing resources on the current satellite can quickly complete the virtualization of satellite resources, and based on the modes of single-satellite pre-computing and master-slave satellite load balancing, the timeliness of the algorithms is improved, and the timeliness of service application and the timeliness of response to user demands are ensured;
3. available capacity calculation: through calculation of layering and multiple models, constraints such as time, space, energy, storage, load attributes and tasks are fully considered, user permission and specific requirements in a specific space-time environment are matched, occupied conditions of existing tasks on resources are considered, a standardized space-based resource available capacity list is dynamically constructed, multiple complex characteristics of space-based resources relative to static resources on the ground are overcome, and the method is closer to engineering application practice. As shown in fig. 2.
The user obtains the space-based resource capability list through the terminal system, and the required space-based resource capability can be interacted, selected and combined on line. In the future use scene, the satellite cluster needs to be supported by the basic virtualization function and the inter-satellite interaction capability. Therefore, the space-based resource virtualization method of the chapter is designed and realizes the corresponding virtualization function, and simulation tests are carried out. The simulation test of the space-based resource capacity virtualization method comprises the steps of constructing a satellite-ground deployment, developing and constructing an on-satellite on-orbit virtualization system on a development board, using a flat board as a user terminal, using a virtual network to carry out interaction between a user and a satellite, simulating a user use scene and a space-based information service mode of a simulation user, testing functions and processes of the system to obtain various time indexes, and comparing test results.
The simulation test mainly aims at three kinds of observation loads, namely SAR, high-beam optical load and wide-amplitude optical load; two types of inter-satellite links are laser communication and microwave communication respectively; and three on-satellite processing algorithms, namely a water body, a vehicle, a bridge, a dam and other identification algorithms, an image slice cutting algorithm and a sea area target detection identification algorithm. The satellite cluster takes three stars as an example, and the orbit of the three stars adopts a low-orbit (500km) walker constellation (the inclination angle is 84.7 degrees), and runs on the adjacent orbital planes. The observation loads of the three stars are respectively set as SAR loads, high-beam optical loads and wide-width optical loads. The microwave load and the laser load are used for inter-satellite communication, and the small antenna is used for direct connection with the user terminal for inter-satellite communication. As shown in fig. 2.
Simulation tests are carried out on the space-based resource capacity virtualization method, simulation environments are respectively set up on three basic hardware such as a development board (ZedBoard Zynq-7000) with a PetaLinux system and a tablet personal computer with an Android 5.1.1 system, and the configuration of the software environment and the hardware environment is shown in tables 1 and 2:
TABLE 1 simulation test hardware Environment configuration
TABLE 2 simulation test software Environment configuration
The development board is used for simulating the satellite, the tablet personal computer is used for simulating the operation required by a user, and the router is used for simulating the link between the microwave satellites. The simulation environment architecture is shown in fig. 3. The three stars respectively calculate the capability list aiming at the specific parameters thereof through a space-based resource virtualization method, the capability list is synchronized to the main star through an inter-satellite link, the main star downloads the capability list to the user terminal through the small satellite when passing by, and the user obtains the space-based resource capability list through the terminal, so that the interactive selection and combination of the space-based resource capability can be carried out on line. And then submitting the required capacity to the master satellite through the small antenna, and the master satellite distributes the required capacity condition to the two slave satellites to complete the required application of the space-based resource capacity and realize the real-time query and the requirement submission of the user to the space-based resource.
For typical user requirements, the observation area is tested. The observation request includes an observation region scope, an observation time scope, a load constraint, and the like. The satellite system calls an available observation time interval calculation model, an available data processing time calculation model and an available laser transmission time interval calculation model after receiving an observation request of a user, calculates a capability list, and then downloads the generated capability list to the user terminal for selection by the user.
The time and index design requirements of each stage in the simulation test are shown in table 3, and the resource occupation conditions are shown in table 4:
table 3: simulation test result
Table 4: resource occupancy
According to the test result, on the premise of not considering faults such as load, link and the like, the instant message service response of the user can be supported, and the requirement of an emergency task with high instantaneity is basically met.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and are not limited. Although the present invention has been described in detail with reference to the embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the invention as defined in the appended claims.