CN115801093B - Path planning method for guaranteeing end-to-end deterministic time delay of satellite network - Google Patents

Abstract

A path planning method for ensuring end-to-end deterministic delay of a satellite network, firstly, constructing a satellite network space-time graph based on service characteristics, calculating the transmission time slot according to the mission service volume and the satellite link capacity, dividing the mission action time domain by the time slot, and then establishing the satellite network space-time graph according to the connectivity relationship and connectivity duration of the satellite network nodes in the time slot; then, aiming at the time-varying characteristics of the satellite link, a path planning calculation method is proposed with the mission service volume, the satellite node connectivity link capacity and the satellite node resource allocation as constraint conditions, and the service transmission start and end time and the link connectivity time as judgment conditions; finally, taking the mission access satellite node as the first hop starting point, searching for the next hop path node among all connected adjacent nodes according to the path planning calculation method until the destination node, thereby obtaining the deterministic transmission path of the satellite network, thereby forming a satellite network path planning method with deterministic delay guarantee.

Description

A path planning method to ensure end-to-end deterministic delay in satellite networks

Technical Field

The invention relates to a path planning method for ensuring end-to-end deterministic delay of a satellite network, and belongs to the technical field of communications.

Background technique

Space information networks need to build robust transmission paths for different types of services in the fields of emergency communications, emergency rescue, navigation and positioning, remote sensing and telemetry, national defense security, smart cities, etc., to ensure deterministic accessibility of key business data. However, due to the high-speed movement of satellites in different periods and the dynamic changes in network-borne business loads over time, the topology of space information networks and multi-dimensional network resources (such as link capacity, node storage, etc.) are time-varying, making it difficult to build end-to-end deterministic transmission paths and ensure service quality such as deterministic delay and delay jitter.

Existing satellite network routing algorithms (such as open shortest path routing, connected graph routing, etc.) are designed based on static graph theory and do not take into account the random characteristics of network services and resources themselves. This will cause inconsistent arrival times of service messages at satellite nodes. At the same time, unstable link status will also cause service messages to need to be stored and waited, which will lead to a long-tail effect in the end-to-end delay of the service, causing uncertainty in the delay, affecting the "on-time and accurate" transmission of deterministic services and the timeliness of service messages.

Summary of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and solve the path planning problem under the condition of ensuring end-to-end deterministic delay of the satellite network.

The purpose of the present invention is achieved through the following technical solutions:

A path planning method for ensuring end-to-end deterministic delay of a satellite network, comprising:

The transmission time slot is calculated according to the mission traffic and satellite link capacity, and the mission action time domain is divided by this time slot. Then, the satellite network time-space diagram is established according to the connectivity relationship and connectivity duration of the satellite network nodes in the time slot.

Taking the mission access satellite node as the first hop starting point, the next hop path node is found among all connected adjacent nodes according to the path planning method until the destination node, thereby obtaining the deterministic transmission path of the satellite network, thus forming a satellite network path planning method with deterministic delay guarantee;

The path planning method is as follows: the task business volume, satellite node connection link capacity, satellite node resource allocation are used as constraints, and the business transmission start and end time and link connection time are used as judgment conditions to perform path planning.

Preferably, the basic unit time τ is calculated based on the greatest common divisor _vφ of all traffic volumes included in the task and the intersatellite link capacity parameter C(t); and the task action time domain is divided using the basic unit time as time slots.

Preferably, according to the satellite network space-time graph, the continuous connection time Δt _uv (t _i ,t _i+m ) between any two satellite nodes (u,v) at any m times (t _i ,t _i+m ) can be obtained.

Preferably, the path planning method is specifically as follows:

If the starting node of the pathfinding is the task access satellite source node S, the starting time is the task access time t _{s_start} . According to the link capacity C(s,k) between the starting node and the connected satellite node, the transmission end time t _{sk_end} of the task traffic on the satellite link is calculated. The calculation method is: Then the task traffic transmission time Δt _sk (M) = t _{sk _ end} - t _{s _ start} , select the satellite node connected to the start node in the set Q, if Δt _sk (M) is within the continuous interval of the satellite node (s, k) connection time, that is, Δt _sk (M) ≤ Δt _uv (t _i , t _i+m ), u = s, v = k, t _{s _ start} ≥ _{t i} , t _{sk_end} ≤ _{t i+m} , then the satellite node k is used as the current path-finding node and written into the deterministic path node set P, and the node is deleted from the set Q; if Δt _sk (M) > Δt _uv (t _i , t _i+m ), u = s, v = k, that is, the task traffic cannot be transmitted within the continuous interval of the satellite node (s, k) connection time, then the satellite node k does not meet the requirements;

If the starting node of the pathfinding is the intermediate node k of the satellite network, the starting time of the continuous connection time of the next-hop satellite node j connected to the node k in the set Q is t _{kj_start} , t _{s_start} <t _{kj_start} ≤t _{sk_end} ; according to the link capacity C(k,j) between the starting node and the connected satellite node, the transmission end time t _{kj_end} of the task traffic on the satellite link is calculated, and the calculation method is: At the same time, the cache constraints of node k are satisfied: Then the task traffic transmission time Δt _kj (M) = t _{kj_end} - t _{kj_start} . If Δt _kj (M) is within the continuous interval of the satellite node (k, j) connection time, that is, Δt _kj (M) ≤ Δt _uv (t _i , t _i+m ), u = k, v = j, t _{kj_start} ≥ _{t i} , t _{kj_end} ≤ _{t i+m} , then the satellite node j is used as the current path-finding node and written into the deterministic path node set P, and the node is deleted from the set Q; if Δt _kj (M) > Δt _uv (t _i , t _i+m ), u = k, v = j, it means that the task traffic cannot be transmitted within the continuous interval of the satellite node (k, j) connection time, and the satellite node j does not meet the requirements;

If j=D, that is, when the path is found to the destination satellite node, the path finding ends; if j≠D, that is, when the path is not found to the destination satellite node, the path finding is restarted.

A path planning method for ensuring end-to-end deterministic delay of a satellite network, comprising:

S1. Determine the mission requirements; determine the satellite network intersatellite link capacity parameter C(t) at different times;

S2. Calculate the basic unit time of all business transmissions included in the task as a time slot, calculate the basic unit time τ, and divide the task action time domain based on this basic unit time as the time slot;

S3, obtain the connectivity relationship diagram of all satellite nodes within the mission action time domain T;

S4. Set the deterministic path node set to P, take the task access satellite node as the source node S, and write the node into the deterministic path node set P;

S5. Set all satellite nodes in the satellite network except the source node S as set Q, and determine whether the set Q is empty. If it is empty, proceed to step S7; if not, proceed to step S6.

S6. Taking the task access time as the starting time _ts-start , determine the next-hop satellite node according to the relationship between the service transmission time Δt(M), the satellite node buffer capacity Buffer(u), and the satellite node connection time _Δtuv ( _ti , _ti+m );

S7. Determine whether the deterministic path node set P is the final deterministic path set; if the destination satellite node D is in the deterministic path node set P, that is, D∈P, then the path finding ends, the satellite nodes in the deterministic path node set P are combined into a path in order, and the transmission time of the task traffic between each node is recorded, which is the end-to-end transmission deterministic delay of the path; if This means that there is no path that meets the conditions and the path finding ends.

Preferably, the task requirements include task traffic volume M, task-included traffic types N, traffic volume of each traffic is V _i (i=1, 2, ..., N), task start access satellite node S, task destination satellite node D, and task action time domain T.

Preferably, according to the connectivity relationship graph of all satellite nodes in the task action time domain T, the continuous connectivity time Δt _uv (t _i ,t _i+m ) between any two satellite nodes (u,v) at any m times (t _i ,t _i+m ) can be obtained, m∈(1,2，…,n).

Preferably, the basic unit time τ is calculated based on the greatest common divisor _vφ of all traffic volumes contained in the task and the inter-satellite link capacity parameter C(t).

Preferably, step S6 specifically includes:

S61. If the starting node of the pathfinding is the task access satellite source node S, the starting time is the task access time _{ts_start} . According to the link capacity C(s,k) between the starting node and the connected satellite node, the transmission end time _{tsk_end} of the task traffic on the satellite link is calculated. The calculation method is: Then the task traffic transmission time Δt _sk (M) = t _{sk _ end} - t _{s _ start} , select the satellite node connected to the start node in the set Q, if Δt _sk (M) is within the continuous interval of the satellite node (s, k) connection time, that is, Δt _sk (M) ≤ Δt _uv (t _i , _{t i+m} ), u = s, v = k, t s _{_ start} ≥ _{t i} , t _{sk _ end} ≤ _{t i+m} , then the satellite node k is used as the current path-finding node, and is written into the deterministic path node set P, and the node is deleted from the set Q; if Δt _sk (M) > Δt _uv (t _i , t _i+m ), u = s, v = k, that is, the task traffic cannot be transmitted within the continuous interval of the satellite node (s, k) connection time, then the satellite node k does not meet the requirements, and return to step S5;

S62. If the starting node of the path search is an intermediate node k in the satellite network, the starting time of the continuous connection time of the next-hop satellite node j connected to the node k in the set Q is t _{kj_start} , t _{s_start} <t _{kj_start} ≤t _{sk_end} ; according to the link capacity C(k,j) between the starting node and the connected satellite node, the transmission end time t _{kj_end} of the task traffic on the satellite link is calculated, ^and the calculation method is: At the same time, the cache constraints of node k are satisfied: Then the task traffic transmission time Δt _kj (M) = t _{kj_end} - t _{kj_start} . If Δt _kj (M) is within the continuous interval of the satellite node (k, j) connection time, that is, Δt _kj (M) ≤ Δt _uv (t _i , t _i+m ), u = k, v = j, t _{kj_start} ≥ _{t i} , t _{kj_end} ≤ _{t i+m} , then the satellite node j is used as the current path-finding node and written into the deterministic path node set P, and the node is deleted from the set Q; if Δt _kj (M) > Δt _uv (t _i , t _i+m ), u = k, v = j, it means that the task traffic cannot be transmitted within the continuous interval of the satellite node (k, j) connection time, then the satellite node j does not meet the requirements, and the process returns to step S5;

If j=D in step S63, that is, the destination satellite node is found, the path finding is completed and step S7 is performed; if j≠D, that is, the destination satellite node is not found, the process returns to step S5.

A computer-readable storage medium stores computer program instructions, which, when loaded and executed by a processor, cause the processor to execute the path planning method for ensuring end-to-end deterministic delay of a satellite network.

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

(1) The present invention calculates the transmission time slot according to the business volume and the cumulative flow of the satellite link, and divides the task action time domain according to the time slot, and then establishes a satellite network time continuity diagram according to the connectivity relationship and connectivity duration of the satellite network nodes in the time slot; forms a path planning calculation method based on the task business volume, the start time and end time of the business transmission, and the satellite node connectivity link capacity and satellite node storage occupancy as constraints; and uses the task access satellite node as the first hop starting point, and searches for the next hop path node in all connected adjacent nodes according to the path calculation method until the destination node, thereby obtaining a deterministic transmission path of the satellite network, eliminating the waiting delay caused by business storage, and realizing deterministic transmission of multiple types of business.

(2) The method of the present invention proposes a method for constructing a satellite network spatiotemporal graph oriented to business characteristics, calculates the transmission time slot according to the business volume and the cumulative flow of satellite link transmission, divides the task action time domain based on this time slot, and establishes a satellite network spatiotemporal graph according to the connectivity relationship of satellite nodes within the divided time period, which can accurately adapt to the transmission requirements of different characteristic services.

(3) The method of the present invention calculates the transmission time slot according to the characteristics of different satellite network services, obtains the time slot occupancy of different services, ensures that the service data packet can be completely transmitted within the satellite node connection time, and eliminates the delay uncertainty caused by waiting for the link connection.

(4) The method of the present invention determines the start and end time of service transmission according to the cumulative traffic of the links between different satellite nodes, accurately describes the relationship between the service traffic transmission time and the satellite node connection time, and constructs a deterministic delay path with time attributes, thereby ensuring the end-to-end deterministic transmission of services under time-varying link conditions.

(5) The method of the present invention takes into account the time-varying characteristics of the link between satellite nodes, calculates the service transmission time based on the cumulative flow of the link, and realizes deterministic transmission of the service under the condition of dynamic link changes by accurately controlling the start transmission time of the upstream and downstream satellite nodes.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic diagram of the satellite network topology.

Figure 2 is a satellite node connectivity diagram.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

A path planning method for ensuring end-to-end deterministic delay of a satellite network is proposed. First, a satellite network spatiotemporal graph is constructed based on service characteristics. The transmission time slot is calculated according to the mission service volume and the satellite link capacity, and the mission action time domain is divided according to the time slot. Then, the satellite network spatiotemporal graph is established according to the connectivity relationship and connectivity duration of the satellite network nodes in the time slot. Then, a path planning calculation method is proposed based on the time-varying characteristics of the satellite link, which takes the mission service volume, the satellite node connectivity link capacity and the satellite node resource allocation (such as storage occupancy) as constraint conditions, and the service transmission start and end time and the link connectivity time as judgment conditions. Finally, the mission access satellite node is used as the first hop starting point, and the next hop path node is found in all connected adjacent nodes according to the path planning calculation method until the destination node, thereby obtaining the deterministic transmission path of the satellite network, thereby forming a satellite network path planning method with deterministic delay guarantee.

Embodiment 1:

A path planning method for ensuring end-to-end deterministic delay of a satellite network, comprising:

S1. When a task with a deterministic delay guarantee requirement starts, the user initiates the task requirement and notifies the satellite network management center. The task requirement includes the task traffic volume M, the types of services included in the task N, the traffic volume of each service is V _i (i=1,2,…,N), the task start access satellite node S, the task destination satellite node D, the task action time domain T and other parameter information. The satellite network management center can obtain the satellite network inter-satellite link capacity parameter C(t) at different times;

S2. The basic unit time of all business transmissions included in the calculation task is the time slot, and the basic unit time τ is calculated based on the greatest common divisor v _φ of all business volumes included in the task and the inter-satellite link capacity parameter C(t). The task action time domain is divided using this basic unit time as the time slot, and the number of moments obtained is n. That is, t ₁ , t ₂ , … t _n .

S3.According to the satellite network topology, the connectivity relationship diagram of all satellite nodes in the mission action time domain T is obtained, and the continuous connectivity time Δt _uv (t _i ,t _i+m ) between any two satellite nodes (u,v) at any m times (t _i ,t _i+m ) can be obtained, m∈(1,2，…,n);

S4. Set the deterministic path node set to P, take the task access satellite node as the source node S, and write the node into the deterministic path node set P;

S5. Set all satellite nodes in the satellite network except the source node S as a set Q, and determine whether the set Q is empty. If it is empty, proceed to step S7; if it is not empty, proceed to step S6.

S6. Taking the task access time as the starting time _ts-start , determine the next hop satellite node according to the relationship between the service transmission time Δt(M), the satellite node buffer capacity Buffer(u) and the satellite node connection time _Δtuv ( _ti , _ti+m ). Step S6 is specifically as follows:

S61 If the starting node of the path finding is the task access satellite source node S, the starting time is the task access time _{ts_start} . According to the link capacity C(s,k) between the starting node and the connected satellite node, the transmission end time _{tsk_end} of the task traffic on the satellite link is calculated. The calculation method is: Then the task traffic transmission time Δt _sk (M) = t _{sk _ end} - t _{s _ start} , select the satellite node connected to the start node in the set Q, if Δt _sk (M) is within the continuous interval of the satellite node (s, k) connection time, that is, Δt _sk (M) ≤ Δt _uv (t _i , _{t i+m} ), u = s, v = k, t s _{_ start} ≥ _{t i} , t _{sk _ end} ≤ _{t i+m} , then the satellite node k is used as the current path-finding node, and is written into the deterministic path node set P, and the node is deleted from the set Q. If Δt _sk (M) > Δt _uv (t _i , t _i+m ), u = s, v = k, that is, the task traffic cannot be transmitted within the continuous interval of the satellite node (s, k) connection time, the satellite node k does not meet the requirements, and the process returns to step S5.

S62 If the starting node of the path search is the intermediate node k of the satellite network, the starting time of the continuous connection time of the next hop satellite node j connected to the node k in the set Q is t _{kj_start} , t _{s_start} <t _{kj_start} ≤t _{sk_end} . According to the link capacity C(k,j) between the starting node and the connected satellite node, the transmission end time t _{kj_end} of the task traffic on the satellite link is calculated, and the calculation method is: At the same time, the cache constraints of node k are satisfied: Then the task traffic transmission time Δt _kj (M) = t _{kj_end} - t _{kj_start} . If Δt _kj (M) is within the continuous interval of the satellite node (k, j) connection time, that is, Δt _kj (M) ≤ Δt _uv (t _i , t _i+m ), u = k, v = j, t _{kj_start} ≥ _{t i} , t _{kj_end} ≤ _{t i+m} , then the satellite node j is used as the current path-finding node and written into the deterministic path node set P, and the node is deleted from the set Q. If Δt _kj (M) > Δt _uv (t _i , t _i+m ), u = k, v = j, it means that the task traffic cannot be transmitted within the continuous interval of the satellite node (k, j) connection time, and the satellite node j does not meet the requirements, and the process returns to step S5.

If j=D in step S63, that is, the destination satellite node is found, the path finding is completed and step S7 is performed; if j≠D, that is, the destination satellite node is not found, the process returns to step S5.

S7. Determine whether the deterministic path node set P is the final deterministic path set. If the destination satellite node D is in the deterministic path node set P, that is, D∈P, then the path search ends, the satellite nodes in the deterministic path node set P are combined into a path in order, and the transmission time of the task traffic between each node is recorded, which is the end-to-end transmission deterministic delay of the path; if This means that there is no path that meets the conditions and the path finding ends.

Embodiment 2:

A path planning method for ensuring end-to-end deterministic delay of a satellite network, comprising:

S1. When a task with a deterministic delay guarantee requirement starts, the user initiates the task requirement to notify the satellite network management center. The task requirement includes the task traffic volume M of 2 units of data, the task contains 2 types of services N=2, the service rate V ₁ =V ₂ =1 unit of data, the task start access satellite node A, the task destination satellite node D, the task action time domain T is divided into 6 units of time and other parameter information. The satellite network intersatellite link capacity parameter C(t) obtained by the satellite network management center is 1 unit of data;

S2. Calculate the basic unit time of all business transmissions included in the task, and calculate the basic unit time τ based on the greatest common divisor v _φ = 1 of all business volumes included in the task and the inter-satellite link capacity parameter C(t). We get τ = 1. Using this basic unit time to divide the task action time domain, the number of moments obtained is n. That is (t ₀ , t ₁ , t ₂ , t ₃ , t ₄ , t ₅ ).

S3. Assuming that the satellite network topology contains 4 satellite nodes, as shown in Figure 1, obtain the connectivity relationship diagram of all satellite nodes in the task action time domain T, and obtain the continuous connectivity time Δt _uv (t _i ,t _i+m ) between any m moments (t _i ,t _i+m ), m∈(1,2，…,n), as shown in Figure 2;

S4. Set the deterministic path node set to P, take the task access satellite node as the source node A, and write the node into the deterministic path node set P, that is, P = {A};

S5. Set the set of all satellite nodes in the satellite network except the source node A to Q = {B, C, D}. If the set Q is determined to be non-empty, proceed to step S6.

S6. Taking the task access time as the starting time _{ts_start} , determine the next hop satellite node according to the relationship between the service transmission time Δt(M), the satellite node buffer capacity Buffer(u) and the satellite node connection time _Δtuv ( _ti , _ti+m ). Step S6 is specifically as follows:

S61 According to step S4, the starting node of the path finding is the task access satellite source node A, and the starting time is the task access time t ₀ . For the convenience of calculation, it is assumed that the traffic is transmitted at full rate at the link capacity. Then the transmission time of the task traffic on the satellite link is Δt(M)=2 unit time, and the transmission end time on the satellite link is t ₂ . Among all satellite nodes (B, C) connected to the starting node A, among the two links L _AB and L _AC , the L _AC link does not have a connected time period starting from time t ₀ , while the connected time period of the L _AB link is [t ₀ -t ₂ ], then Δt _AB (t ₀ ,t ₂ ) = Δt(M), which satisfies the task traffic to complete transmission within the continuous interval of the connected time, t _{sk _ end} = t ₂ , then the satellite node B is used as the current pathfinding node and written into the deterministic path node set P, that is, P = {A, B}, and the satellite node B is deleted from the set Q, that is, Q = {C, D}.

S62 According to step S61, the current pathfinding node B is the satellite network intermediate node k=B, and the next hop satellite node j=C, D connected to the node. Among all satellite nodes (C, D) connected to satellite node B, the starting time t _{kj_start} of the continuous connection time should satisfy t _{s_start} <t _{kj_start} ≤t _{sk_end} , and the connection time should satisfy Δt _kj (M)≥Δt(M).

In the two links L _BC and L _BD , the connectivity time period of the L _BD link is [t ₃ -t ₅ ], t ₀ <t ₃ >t ₂ , which does not meet the transmission condition. The connectivity time period of the L _BC link is [t ₁ -t ₄ ], then Δt _BC (t ₁ ,t ₄ )＞Δt(M), and t ₀ <t ₁ ≤t ₂ , and the starting time of its continuous connectivity time is t _{kj_start} ＝t ₁ , t _{kj_end} ＝t ₃ , which meets the requirement that the task traffic is transmitted within the continuous interval of the connectivity time. Then the satellite node C is used as the current pathfinding node and written into the deterministic path node set P, that is, P＝{A,B,C}, and the satellite node C is deleted from the set Q, that is, Q＝{D}.

S63 According to step S62, the current pathfinding node C is the satellite network intermediate node k=C, and the next hop satellite node j=D connected to the node. Among all satellite nodes D connected to satellite node C, the starting time _{tkj_start} of the continuous connection time should satisfy _{ts_start} < _{tkj_start ≤tsk_end} , and the connection time should satisfy _Δtkj (M)≥Δt(M).

The connected time period of the L _CD link is [t ₀ -t ₁ ] and [t ₂ -t ₄ ], where Δt _CD (t ₀ ,t ₁ )＜Δt(M), which does not meet the transmission condition. However, Δt _CD (t ₂ ,t ₄ )＝Δt(M), and t ₁ <t ₂ ≤t ₃ , and the starting time of its continuous connected time is t _{kj_start} ＝t ₂ , t _{kj_end} ＝t ₄ , which satisfies the task traffic to complete the transmission within the continuous interval of the connected time. Then the satellite node D is used as the current path-finding node and written into the deterministic path node set P, that is, P＝{A,B,C,D}, and the satellite node D is deleted from the set Q, that is,

S64: According to the satellite node j=D obtained in step S63, the path is found to the destination satellite node, and the path finding is completed, and step S7 is performed.

S7. Determine whether the deterministic path node set P is the final deterministic path set. If D∈P, the path search ends, and the satellite nodes in the deterministic path node set P are sequentially combined into a path, i.e., A→B→C→D, and the transmission time of the task traffic between each node is recorded, i.e., the end-to-end deterministic transmission delay of the path, and the delay value is t ₄ -t ₀ = 4 unit time.

The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims (6)

1. A path planning method for ensuring end-to-end deterministic delay in a satellite network, comprising: The transmission time slot is calculated according to the mission traffic and satellite link capacity, and the mission action time domain is divided by this time slot. Then, the satellite network time-space diagram is established according to the connectivity relationship and connectivity duration of the satellite network nodes in the time slot. Taking the mission access satellite node as the first hop starting point, the next hop path node is found among all connected adjacent nodes according to the path planning method until the destination node, thereby obtaining the deterministic transmission path of the satellite network, thus forming a satellite network path planning method with deterministic delay guarantee; Among them, the task business volume, satellite node connection link capacity, satellite node resource allocation are used as constraint conditions, and the business transmission start and end time and link connection time are used as judgment conditions to carry out path planning; The path planning method is as follows: According to the satellite network spatiotemporal graph, the continuous connectivity time Δt _uv (t _i ,t _i+m ) between any two satellite nodes (u,v) at any m times (t _i ,t _i+m ) can be obtained; If the starting node of the pathfinding is the task access satellite source node S, the starting time is the task access time t _{s_start} . According to the link capacity C(s,k) between the starting node and the connected satellite node, the transmission end time t _{sk_end} of the task traffic on the satellite link is calculated. The calculation method is: M is the task traffic; the transmission time of the task traffic Δt _sk (M) = t _{sk _ end} - t _{s _ start} , select the satellite node connected to the start node in the set Q, if Δt _sk (M) is within the continuous interval of the satellite node (s, k) connection time, that is, Δt _sk (M) ≤ Δt _uv (t _i , t _i+m ), u = s, v = k, t s _{_ start} ≥ _{t i} , t _{sk _ end} ≤ _{t i+m} , then the satellite node k is used as the current path-finding node and written into the deterministic path node set P, and the node is deleted from the set Q; if Δt _sk (M) > Δt _uv (t _i , t _i+m ), u = s, v = k, that is, the task traffic cannot be transmitted within the continuous interval of the satellite node (s, k) connection time, then the satellite node k does not meet the requirements; If the starting node of the pathfinding is the intermediate node k of the satellite network, the starting time of the continuous connection time of the next-hop satellite node j connected to the node k in the set Q is t _{kj_start} , t _{s_start} <t _{kj_start} ≤t _{sk_end} ; according to the link capacity C(k,j) between the starting node and the connected satellite node, the transmission end time t _{kj_end} of the task traffic on the satellite link is calculated, and the calculation method is: At the same time, the cache constraints of node k are satisfied: Buffer(k) is the buffer capacity of the satellite node; the task traffic transmission time Δt _kj (M) = t _{kj_end} - t _{kj_start} . If Δt _kj (M) is within the continuous interval of the satellite node (k, j) connection time, that is, Δt _kj (M) ≤ Δt _uv (t _i , t _i+m ), u = k, v = j, t _{kj_start} ≥ _{t i} , t _{kj_end} ≤ _{t i+m} , then the satellite node j is used as the current path-finding node and written into the deterministic path node set P, and the node is deleted from the set Q; if Δt _kj (M) > Δt _uv (t _i , t _i+m ), u = k, v = j, it means that the task traffic cannot be transmitted within the continuous interval of the satellite node (k, j) connection time, and the satellite node j does not meet the requirements; If j=D, D is the mission destination satellite node, that is, when the path is found to the destination satellite node, the path finding ends; if j≠D, that is, when the path is not found to the destination satellite node, the path finding is repeated. 2. The path planning method according to claim 1 is characterized in that the basic unit time τ is calculated based on the greatest common divisor _vφ of all traffic volumes contained in the task and the inter-satellite link capacity parameter C(t); and the task action time domain is divided into time slots based on the basic unit time. 3. A path planning method for ensuring end-to-end deterministic delay in a satellite network, characterized by comprising: S1. Determine the mission requirements; determine the satellite network intersatellite link capacity parameter C(t) at different times; S2. Calculate the basic unit time of all business transmissions included in the task as a time slot, divide the task action time domain by this time slot, and obtain the number of time moments as n; S3, obtain the connectivity relationship diagram of all satellite nodes within the mission action time domain T; S4. Set the deterministic path node set to P, take the task access satellite node as the source node S, and write the node into the deterministic path node set P; S5, set all satellite nodes of the satellite network except the source node S as a set Q, and determine whether the set Q is empty, if it is empty, proceed to step S7; if not, proceed to step S6; S6. Taking the task access time as the starting time _ts-start , determine the next-hop satellite node according to the relationship between the service transmission time Δt(M), the satellite node buffer capacity Buffer(k), and the satellite node connection time _Δtuv ( _ti , _ti+m ); According to the connectivity relationship diagram of all satellite nodes in the task action time domain T, the continuous connectivity time Δt _uv (t _i ,t _i+m ) between any two satellite nodes (u,v) at any m times (t _i ,t _i+m ) can be obtained, m∈(1,2，…,n); Step S6 is specifically as follows: S61. If the starting node of the pathfinding is the task access satellite source node S, the starting time is the task access time _{ts_start} . According to the link capacity C(s,k) between the starting node and the connected satellite node, the transmission end time _{tsk_end} of the task traffic on the satellite link is calculated. The calculation method is: M is the task traffic; the transmission time of the task traffic Δt _sk (M) = t _{sk _ end} - t _{s _ start} , select the satellite node connected to the start node in the set Q, if Δt _sk (M) is within the continuous interval of the satellite node (s, k) connection time, that is, Δt _sk (M) ≤ Δt _uv (t _i , t _i+m ), u = s, v = k, t s _{_ start} ≥ t _i , t _{sk _ end} ≤ _{t i+m} , then the satellite node k is used as the current path-finding node, and is written into the deterministic path node set P, and the node is deleted from the set Q; if Δt _sk (M) > Δt _uv (t _i , t _i+m ), u = s, v = k, that is, the task traffic cannot be transmitted within the continuous interval of the satellite node (s, k) connection time, then the satellite node k does not meet the requirements, and return to step S5; S62. If the starting node of the path search is an intermediate node k in the satellite network, the starting time of the continuous connection time of the next-hop satellite node j connected to the node k in the set Q is t _{kj_start} , t _{s_start} <t _{kj_start} ≤t _{sk_end} ; according to the link capacity C(k,j) between the starting node and the connected satellite node, the transmission end time t _{kj_end} of the task traffic on the satellite link is calculated, and the calculation method is: At the same time, the cache constraints of node k are satisfied: Then the task traffic transmission time Δt _kj (M) = t _{kj_end} - t _{kj_start} . If Δt _kj (M) is within the continuous interval of the satellite node (k, j) connection time, that is, Δt _kj (M) ≤ Δt _uv (t _i , t _i+m ), u = k, v = j, t _{kj_start} ≥ _{t i} , t _{kj_end} ≤ _{t i+m} , then the satellite node j is used as the current path-finding node and written into the deterministic path node set P, and the node is deleted from the set Q; if Δt _kj (M) > Δt _uv (t _i , t _i+m ), u = k, v = j, it means that the task traffic cannot be transmitted within the continuous interval of the satellite node (k, j) connection time, then the satellite node j does not meet the requirements, and the process returns to step S5; S63: If j=D, D is the mission destination satellite node, that is, when the path is found to the destination satellite node, the path finding is completed and step S7 is performed; if j≠D, that is, when the path is not found to the destination satellite node, the process returns to step S5; S7. Determine whether the deterministic path node set P is the final deterministic path set; if the destination satellite node D is in the deterministic path node set P, that is, D∈P, then the path finding ends, the satellite nodes in the deterministic path node set P are combined into a path in order, and the transmission time of the task traffic between each node is recorded, which is the end-to-end transmission deterministic delay of the path; if This means that there is no path that meets the conditions and the path finding ends. 4. The path planning method according to claim 3 is characterized in that the task requirements include task business volume M, task types N, the business volume of each business is V _i (i=1, 2, ..., N), task start access satellite node S, task destination satellite node D, and task action time domain T. 5. The path planning method according to claim 3 is characterized in that the basic unit time τ is calculated based on the greatest common divisor _vφ of all traffic volumes contained in the task and the inter-satellite link capacity parameter C(t). 6. A computer-readable storage medium having computer program instructions stored thereon, wherein when the computer program instructions are loaded and executed by a processor, the processor is caused to execute the method according to claim 1 or 2.