CN102118820B - Continuous state routing algorithm of satellite link network - Google Patents

Abstract

The invention discloses a continuous state routing algorithm of a satellite link network, which comprises the following steps: (1) registering the time of switching between a link connected state and a link unconnected state within the entire simulation time, and establishing a link state switching table; (2) searching and recording paths within the entire simulation time; (3) filtering the paths and storing the optimal one; and (4) performing full-path integration by using the Dijkstra shortest path algorithm. The routing algorithm disclosed by the invention is different from the traditional satellite link network routing algorithm in that: the routing algorithm continuously records and uses the time-varying dynamic topology of the satellite link network within the entire simulation time without simplifying the topology into discrete static topology by dividing time intervals. The routing algorithm stores the most complete network dynamic information, thus the best routing design result can be provided; and moreover, the numerical form is simple, the paths are filtered in the path registration process, thus the workload of full-path integration is reduced.

Description

A kind of satellite link network continuous state routing algorithm

Technical field

The present invention relates to a kind of satellite link algorithm network routing, belong to satellite constellation communication route technology field.

Background technology

Routing algorithm is the method for carrying out path planning in network according to certain index, and routing Design namely is to utilize routing algorithm in the process of network acquisition optimal path, is also referred to as routing optimality.Satellite constellation has formed a link network after having realized inter-satellite link.This network is different from the time change attitude characteristics that usually deliver personally open network and computer network are its topological structure, shows as that link between the satellite and the link between satellite and the ground based terminal not only become during length but also the life-span is limited.Therefore the limited connection limited duration that refers to link of link life-span, link switch being communicated with to be communicated with between the two states with nothing.These change characteristics for the moment of satellite link network make its routing issue not solve with general routing algorithm.

Chinese scholars has proposed a large amount of routing algorithms at the satellite link network.These algorithms are all based on the discrete state emulation to the satellite link network.Discrete state emulation is upgraded the network configuration state information at each interval endpoint, thereby the continuous differentiation of network topology is separated into a series of static momentary status by the whole simulation time is divided into the minizone.Traditional satellite link algorithm network routing is namely used general routing algorithm in these discrete static topologys and carry out path planning in each time interval, obtains path segments.Finish the complete trails of whole simulation in the time by each interval path segments of connecting at last.

Noakes, M.D.; Cain, J.B.; Et al, An adaptive link assignment algorithm for dynamically changing topologies.IEEE Trans.Communications, vol.41, May 1993, Page (s): 694-706 one literary composition has proposed the thought with the continuous state evolution process discretization of satellite link network at first.

Chang, H.S.; Kim, B.W.; Lee, C.G.; Et al, FSA-based link assignment and routing in low-Earth orbit satellite networks.IEEE Trans.Vehicular Technology, vol.47, August 1998, Page (s): among the 1037-1048 finite state machine principle Finite State Automaton (FSA) is applied to satellite link network dynamic simulation, has proposed the routing algorithm based on this emulation.In the FSA emulation simulation time is divided into the interval by equal length, regularly upgrades the satellite network topology.But because the life-span is limited, some link is inner generation state conversion in a certain interval, and in this case, these links can't continue current whole interval, show as imperfect link.Because the FSA routing algorithm will be used as static structure in the network topology that interval endpoint upgrades and carry out path planning, so this imperfect link has a strong impact on the accuracy of path planning.Therefore, the FSA algorithm dictates of Chang proposition is given up all imperfect links.Some link informations have been ignored in this processing, can't guarantee routing Design result's optimality, and can cause some interval puppet that occurs not have the phenomenon of connection, namely cause certain interval not have the situation of any link because having given up all imperfect links.

Gounder, V.V.; Prakash, R.; Abu-Amara, H., Routing in LEO-based satellite networks.Proceeding of IEEE Emerging Technologies Symposium, Wireless Communications and Systems, Richardson, 1999, Page (s): another kind of discrete state emulation mode at the satellite link network has been proposed among the 91-96, after be called as snapshot.Snapshot is handled siding-to-siding block length flexibly at the deficiency of FSA method, allows interval endpoint and Link State switching instant be consistent.Namely any link generation state switches in network, then finishes current interval, between the beginning newly developed area, and upgrades network topological information.Therefore routing algorithm based on snapshot can preserve complete link information, but because the Link State switching is frequent, interval and path segments huge amount, efficiency of algorithm is low.

Kai Fa all kinds of routing algorithms are all bar none based on FSA or snapshot emulation subsequently.Because these two kinds of emulation modes have all used discrete state, namely in same interval, network topology is regarded as staticly, so these routing algorithms have all ignored the multidate information of linkage length, are being in the routing Design of index with the time delay, the result exists than mistake.

Summary of the invention

The objective of the invention is provides a kind of continuous state routing algorithm in order to overcome the shortcoming of above routing algorithm based on discrete state.Algorithm of the present invention does not carry out interval division to simulation time, and in whole simulation disposable operation in the time, the topology of record network develops information, searching route and carries out complete trails and optimizes and combines.

A kind of satellite link network continuous state routing algorithm of the present invention comprises following concrete steps:

Step 1, set up the Link State switching table.Record the Origin And Destination that all Link State switching instants are also used each bar link connecting section of " 1 " and " 1 " mark respectively in time in whole simulation:

L _ij＝Link _ij{S _i，S _j，t ₀，′1′，t ₁，′-1′，t ₃，′1′，…，t _n，′1′，t _n+1，′-1′}(1)

In the formula, S _iAnd S _jBe satellite or topocentric numbering, L _IjBe S _iWith S _jBetween link, Link _Ij... be link L _IjInformation set, t ₀..., t _N+1Be Link State switching instant point.Link L _IjCan be expressed as at the connecting section of whole simulation in the time:

L(S _i，S _j)＝[t ₀ t ₁]∪[t ₃ t ₄]∪…∪[t _n t _n+1](2)

Step 2, search and record path.Whole simulation in the time by given communication line starting point and terminal point searching route, the record path connecting section, i.e. initial moment in path life-span and stopping constantly, and by the numbering of the satellite that from circuit starting point journal path to terminal, comprises:

P _i＝Path _i{S _i1，…S _in，t _i0，′1′，t _i1，′-1′}(3)

In the formula, P _iBe the i paths that searches, t _I0And t _I1The initial sum that is respectively the path life-span stops constantly.This two moment can be determined by the common factor of the connecting section of the link that comprises in the path:

$\left[\begin{array}{cc}{t}_{i0}& t_{i1}\end{array}\right]\⊆L_{i1,i2}\∩L_{i2,i3}\∩...\∩L_{i(n-1),\mathrm{in}}---\left(4\right)$

The more than interval of right-hand member common factor possibility in the formula is with each interval connecting section storage as an independent pathway of occuring simultaneously, [t _I0t _I1] therefore only get one of them interval of occuring simultaneously, other interval saves as new route.Deposit all independent pathways in the path storehouse.

Step 3, carry out path filtering.From the second path, search a new route P at every turn _i, then in the storehouse, path, carry out two-way approach and filter.At first check and whether have a paths P in the storehouse, path _k, make following two conditions set up simultaneously:

(1） $\left[\begin{array}{cc}{t}_{k0}& t_{k1}\end{array}\right]\⊇\left[\begin{array}{cc}{t}_{i0}& t_{i1}\end{array}\right]$

(2) $\{S_{k1},...,S_{\mathrm{km}}\}\⋐\{S_{i1},...,S_{\mathrm{in}}\}$

If then abandon path P _i, otherwise with P _iDeposit the storehouse, path in, and check that conversely arbitrary in the storehouse, path is removed P _iOutside path P _kWhether satisfy simultaneously:

(1) $\left[\begin{array}{cc}{t}_{k0}& t_{k1}\end{array}\right]\⊇\left[\begin{array}{cc}{t}_{i0}& t_{i1}\end{array}\right]$

(2) $\{S_{k1},...,S_{\mathrm{km}}\}\⊃\{S_{i1},...,S_{\mathrm{in}}\}$

If, then with path P _kFrom the storehouse, path, delete.The path is bi-directional filtered to be based on the path principle of selecting the superior: if path P _iWith path P _jServe same time period and P _iService time covered P _jService time and P _iUsed satellite is P _jThe subclass of used satellite, then path P _iBe better than path P _j

Step 4, carry out complete trails and integrate.Each paths is used as a node, in the storehouse, path, uses the Dijkstra shortest path first and carry out the path series connection, finish the integration of complete trails.Wherein, the path value in the dijkstra's algorithm is with corresponding routing optimality index such as time delay or the replacement of link switching number.When calculation delay, use integration method according to the dynamic evolution information calculations of linkage length.

P _i＝Path _i{S _i1，…，S _in，t _i0，′1′，t _i1，′-1′，l _i，j}(5)

In the formula, l _iBe the optimization desired value in this path, j is the numbering in its last path that is connected.

The invention has the advantages that:

(1) intactly preserves the multidate information of satellite link network topology in the time in whole simulation, guaranteed routing optimality result's validity and accuracy;

(2) by record chain line state switching instant point, followed the trail of the dynamic of network with simple data message, be convenient to use the connectedness of the method calculating path that the interval seeks common ground simultaneously;

(3) introduction of path filters link, screens the path in advance, integrates for complete trails to alleviate workload.

(4) the routing Design result is more excellent.

Description of drawings

Fig. 1 (a) is based on interval division and the path of the routing algorithm of FSA and handles;

Fig. 1 (b) is based on interval division and the path of the routing algorithm of snapshot and handles;

Fig. 2 is that routing algorithm of the present invention is in the path register of whole simulation in the cycle;

Fig. 3 is the flow chart of routing algorithm of the present invention;

Fig. 4 be this algorithm and FSA algorithm in the embodiment of the invention the routing optimality result relatively.

Embodiment

The present invention is described in further detail with embodiment with reference to the accompanying drawings below.

The present invention is a kind of continuous state routing algorithm that proposes at the deficiency of traditional satellite link algorithm network routing.Fig. 1 (a) and (b) have provided the interval division rule and path processing mode of two kinds of discrete state emulation modes that traditional routing algorithm adopts the satellite link dynamic network.Be different from these routing algorithms, routing algorithm of the present invention carries out routing Design in whole simulation the time, comprises the integration of route searching and complete trails, therefore, the information of every independent pathway all obtains complete registration, rather than becomes the fragment registration by interval division, as shown in Figure 2.

The present invention is a kind of satellite link network continuous state routing algorithm, and algorithm flow specifically may further comprise the steps as shown in Figure 3:

Step 1, set up the Link State switching table.Record the Origin And Destination that all Link State switching instants are also used each bar link connecting section of " 1 " and " 1 " mark respectively in time in whole simulation:

L _ij＝Link _ij{S _i，S _j，t ₀，′1′，t ₁，′-1′，t ₃，′1′，…，t _n，′1′，t _n+1，′-1′}(1)

In the formula, S _iAnd S _jBe satellite or topocentric numbering, L _IjBe S _iWith S _jBetween link, Link _Ij... be link L _IjInformation set, t ₀..., t _N+1Be Link State switching instant point.Link L _IjCan be expressed as at the connecting section of whole simulation in the time:

L(S _i，S _j)＝[t ₀ t ₁]∪[t ₃ t ₄]∪…∪[t _n t _n+1](2)

Under the unequal situation of rotation period of the orbital period of satellite and the earth, the position vector of the link between satellite and the terrestrial user (being called satellite-ground link) in geocentric inertial coordinate system changes in time.It is generally acknowledged to have only when satellite-ground link is namely communicated by letter the situation of the elevation angle greater than certain value with the angle between this ground horizontal plane under, link could be communicated with.This boundary value is called the minimal communications elevation angle.Minimal communications elevation angle requirement according to satellite communication system, can be at whole simulation communication elevation angle of calculating sampling moment point satellite-ground link at first in the time, between two neighbouring sample points, carry out interpolation then and obtain extreme point, last between two adjacent extreme points again interpolation find out the boundary point that the communication elevation angle equals the minimal communications elevation angle, namely satellite-ground link is being communicated with and the non-moment point of switching between the two states that is communicated with.The connecting section of inter-satellite link depends on that the sweep limits of antenna and the earth are earth occultation to stopping of satellite, the situation that also comprises the positive closing inter-satellite link is defined in the above area of 60 degree latitudes as " iridium " constellation and closes inter-satellite link for fear of subpolar region's link interference.Can obtain the state switching instant point of inter-satellite link with similar interpolation method noted earlier according to the regulation of antenna scanning scope, earth occultation condition and positive closing link.These moment point enter connected state with one token, finish connected state with " 1 " mark, thereby finish the registration of connecting section.Because the orbital motion of satellite and the rotation of the earth all are cycle movements, it also is periodically to repeat that the state of link switches.Therefore in whole simulation in the time, the connecting section of each bar link may more than one, but these intervals are not continuous.Article one, link the connection time of whole simulation in the time be these intervals also, as the formula (2).

Step 2, search and record path.Whole simulation in the time by given communication line starting point and terminal point searching route, the record path connecting section, i.e. initial moment in path life-span and stopping constantly, and by the numbering of the satellite that from circuit starting point journal path to terminal, comprises:

P _i＝Path _i{S _i1，…S _in，t _i0，′1′，t _i1，′-1′}(3)

In the formula, P _iBe the i paths that searches, t _I0And t _I1The initial sum that is respectively the path life-span stops constantly.This two moment can be determined by the common factor of the connecting section of the link that comprises in the path:

$\left[\begin{array}{cc}{t}_{i0}& t_{i1}\end{array}\right]\⊆L_{i1,i2}\∩L_{i2,i3}\∩...\∩L_{i(n-1),\mathrm{in}}---\left(4\right)$

The more than interval of right-hand member common factor possibility in the formula is with each interval connecting section storage as an independent pathway of occuring simultaneously, [t _I0t _I1] therefore only get one of them interval of occuring simultaneously, other interval saves as new route.Deposit all independent pathways in the path storehouse.

According to the link information table, at first can set up an adjacent star collection for each satellite or each ground point, has deposited at whole simulation this star or this ground can be linked in the time satellite information and corresponding connecting section the inside.According to these adjacent star relations, the search method of utility tree formula can search the path that connects two terrestrial users.All links all are in connected state in one paths can be communicated with that and if only if the path, and therefore, the connecting section in path is the common factor of the connecting section of its all link of comprising.This common factor may comprise plural discontinuity interval.Integrate complete trails for convenience, each interval in occuring simultaneously is registered as an independent paths.Path starting point moment sequencing by its life-span in the storehouse, path is deposited.

Step 3, carry out path filtering.From the second path, search a new route P at every turn _i, then in the storehouse, path, carry out two-way approach and filter.At first check and whether have a paths P in the storehouse, path _k, make following two conditions satisfy simultaneously:

(1) $\left[\begin{array}{cc}{t}_{k0}& t_{k1}\end{array}\right]\⊇\left[\begin{array}{cc}{t}_{i0}& t_{i1}\end{array}\right]$

(2) $\{S_{k1},...,S_{\mathrm{km}}\}\⋐\{S_{i1},...,S_{\mathrm{in}}\}$

If then abandon path P _i, otherwise with P _iDeposit the storehouse, path in, and check that conversely arbitrary in the storehouse, path is removed P _iOutside path P _kWhether satisfy simultaneously:

(1) $\left[\begin{array}{cc}{t}_{k0}& t_{k1}\end{array}\right]\⊆\left[\begin{array}{cc}{t}_{i0}& t_{i1}\end{array}\right]$

(2) $\{S_{k1},...,S_{\mathrm{km}}\}\⊃\{S_{i1},...,S_{\mathrm{in}}\}$

If, then with path P _kFrom the storehouse, path, delete.The path is bi-directional filtered to be based on the path principle of selecting the superior: if path P _iWith path P _jServe same time period and P _iService time covered P _jService time and P _iUsed satellite is P _jThe subclass of used satellite, then path P _iBe better than path P _j

Step 4, close the path and integrate.Each paths is used as a node, in the storehouse, path, uses the Dijkstra shortest path first and carry out the path series connection, finish the integration of complete trails.Wherein, the path value in the dijkstra's algorithm is with corresponding routing optimality index such as time delay or the replacement of link switching number.When calculation delay, use calculus methods according to the dynamic evolution information calculations of linkage length.

P _i＝Path _i{S _i1，…，S _in，t _i0，′1′，t _i1，′-1′，l _i，j}(5)

In the formula, l _iBe the optimization desired value in this path, j is the numbering in its last path that is connected.Routing algorithm must have certain index, and continuous state routing algorithm of the present invention goes for various indexs, only calculates corresponding desired value as " path " of Dijkstra shortest path first in the process that in the end path is integrated.Route index commonly used has the number of switching and time delay.The integration of complete trails namely selects the path to make up in the storehouse, path according to certain index, thereby makes the complete trails optimum, and is minimum or switch number as time delay.Be example with time delay as index, the process that the path is integrated is as follows.At first, use all path overall delays its connecting section in consistent with the emulation starting point of the initial moment in integral and calculating life-span.Overall delay is the integration of instantaneous time delay in connecting section.Secondly, be that each paths in storehouse, path is sought optimum last path by life-span zero-time sequencing, namely select time delay accumulative total reckling in all paths on it can be connected, the numbering in this last path of optimum of record in current path then, and the time delay bulk registration that the overall delay of current path is added this last path of optimum is the time delay aggregate-value in path at that time.Similar successively, the path in the storehouse, path all obtains the corresponding index value, and has recorded the numbering in optimum last path.At last, in all end of life path consistent with emulation finish time, seek time delay accumulative total reckling, and the numbering in the optimum last path of recording according to it finds last path, reads the numbering in its last path more successively, finally can obtain all paths that optimum complete trails comprises.Be the route index to switch number, then will calculate and be transferred to the link switching times that current path need carry out from last path.For example from path P _i(S ₁, S ₃, S ₅) be transferred to path P _i(S ₁, S ₄, S ₅), need switch through twice link and realize.The minimum number that switches that is similarly that records in the path adds up.

Embodiment: be example with a small-sized LEO rose constellation.This constellation configuration parameters is 42 °: 32/4/1, and orbit altitude is 7728 kms; The minimal communications elevation angle is 10 °, and every star has inter-satellite link in two rails, two rail border inter-satellite links, no positive closing regulation.Long 2 hours of simulation time.The geographical position of circuit two ground terminals is A (0 ° of E, 20 ° of N) and B (120 ° of E, 50 ° of N).To switch number as the routing optimality index.

Step 1, set up the Link State switching table.In 2 hours simulation time, calculate the connecting section of link.

……

L _A，28＝Link _A，28{S _A，S ₂₈，0.0，′1′，174.235，′-1′，6480.908，′1′，7127.136，′-1′}

……

L _B，10＝Link _B，10{S _B，S ₁₀，0.0，′1′，385.135，′-1′，6572.708，′1′，7200.0，′-1′}

……

L _3，10＝Link _3，10{S ₃，S ₁₀，0，′1′，3600，′-1′}

……

L _3，27＝Link _3，27{S ₃，S ₂₇，0，′1′，3600，′-1′}

……

L _10，11＝Link _10，11{S ₁₀，S ₁₁，0，′1′，3600，′-1′}

……

L _27，28＝Link _27，28{S ₂₇，S ₂₈，0，′1′，3600，′-1′}

……

Step 2, search and record path.In whole simulation searching route in the time, each connecting section deposited make an independent paths.Deposit by initial moment sequencing of its life-span in the storehouse, path in the path.Two paths by top listed five links constitute save as respectively No. 3 and No. 321 in the storehouse, path.Because all paths all are the paths from terminal A to terminal B, millet cake numbering in old place can be ignored.

P ₁＝Path ₁{S ₂₈，S ₄，S ₁₁，0.0，′1′，174.236，′-1′}

P ₂＝Path ₂{S ₂₈，S ₂₇，S ₃，S ₄，S ₁₁，0.0，′1′，174.236，′-1′}

P ₃＝Path ₃{S ₂₈，S ₂₇，S ₃，S ₁₀，S ₁₁，0.0，′1′，174.236，′-1′}

……

P ₃₂₁＝Path ₃₂₁{S ₂₈，S ₂₇，S ₃，S ₁₀，S ₁₁，6572.708，′1′，7127.136，′-1′}

……

Step 3, carry out path filtering.The new route that searches and the path of depositing in the storehouse, path are compared, preserve according to qualifications.

Search new route: P _New=Path _New{ S ₈, S ₁, S ₁₆, S ₂₃, 2106.931, ' 1 ', 2256.954, '-1 '

But the path exists in the storehouse: P ₃₄=Path ₃₄{ S ₈, S ₁, S ₁₆, 2097.485, ' 1 ', 2633.823, '-1 '

Because

And

So give up P _New, it is not deposited in the storehouse, path.

Search new route: P _New=Path _New{ S ₁₀, S ₁₁, S ₁₂, 5676.253, ' 1 ', 6500.990, '-1 ', through comparing, not having in the storehouse, path can be with P _NewSo the path of getting rid of is with P _NewBe inserted in the storehouse, path No. 120 position by its zero-time, namely

P ₁₂₀＝Path ₁₂₀{S ₁₀，S ₁₁，S ₁₂，5676.253，′1′，6500.990，′-1′}

So since No. 121, with each paths and P ₁₂₀Compare, find

P ₁₂₅＝Path ₁₂₅{S ₄，S ₃，S ₁₀，S ₁₁，S ₁₂，5728.929，′1′，6299.616，′-1′}

Because And

So with P ₁₂₅From the storehouse, path, delete.When in the storehouse, path, inserting the path that new route or deletion deposited, the path respective sequence after this position move down or on move.

Step 4, carry out complete trails and integrate.For each paths in the storehouse, path calculates its desired value, add up for switching number in the present embodiment, and choose its optimum last path.When optimum last path referred to after being engaged on this path, the switching number accumulative total of current path was minimum, i.e. " path " minimum.The initial moment in life-span, the path identical with the emulation starting point was first path, and they are equivalent to first node in the Dijkstra shortest path first, and therefore switching number accumulative total is 0, and optimum last path number is designated as 0.

……

P ₃＝Path ₃{S ₂₈，S ₂₇，S ₃，S ₁₀，S ₁₁，0.0，′1′，174.236，′-1′，0，0}

……

P ₁₀＝Path ₁₀{S ₂₇，S ₃，S ₁₀，S ₁₁，51.490，′1′，385.135，′-1′，1，3}

……

P ₂₆＝Path ₂₆{S ₂₇，S ₃，S ₁₀，311.832，′1′，1065.382，′-1′，2，10}

……

P ₃₇＝Path ₃₇{S ₂₆，S ₂₇，S ₃，S ₁₀，952.917，′1′，1274.001，′-1′，4，26}

……

P ₆₃＝Path ₆₃{S ₂₆，S ₂₇，S ₃，S ₁₀，S ₉，1204.185，′1′，1951.160，′-1′，6，37}

……

P ₇₉＝Path ₇₉{S ₂₅，S ₃₂，S ₁₇，S ₁₀，S ₉，1859.186，′1′，2159.755，′-1′，10，63}

……

P ₄₀₆＝Path ₄₀₆{S ₉，S ₁₀，S ₁₁，S ₁₈，6454.173，′1′，6951.581，′-1′，36，405}

……

P ₄₂₈＝Path ₄₂₈{S ₉，S ₁₀，S ₁₁，6572.708，′1′，7200.0，′-1′，37，406}

……

P ₄₃₅＝Path ₄₃₅{S ₉，S ₂₄，S ₁₇，S ₁₈，S ₁₁，6572.708，′1′，7200.0，′-1′，39，408}

……

P ₄₄₂＝Path ₄₄₂{S ₃，S ₄，S ₁₁，6637.013，′1′，7200.0，′-1′，40，429}

……

After cumulative calculation is counted in the switching in all paths in finishing the storehouse, path, in constantly consistent with the emulation terminal point path of all end-of-lifes, find out and switch the minimum path of accumulative total, in the present embodiment, P ₄₂₈, P ₄₃₅, P ₄₄₂End of life in the path all is 7200 seconds, and is consistent with the emulation terminal point, wherein P ₄₂₈Switching number accumulative total minimum, be 37 times.From P ₄₂₈Optimum last path register in can to find out its last path be P ₄₀₆, and the like, can obtain complete trails and be

P ₃→P ₁₀→P ₂₆→P ₃₇→P ₆₃→P ₇₉→P ₁₀₁→P ₁₂₉→P ₁₅₉→P ₁₉₆→P ₂₁₉→P ₂₆₅

→P ₂₇₇→P ₂₈₆→P ₃₅₁→P ₃₆₀→P ₄₀₅→P ₄₀₆→P ₄₂₈

The superiority of routing algorithm of the present invention is embodied in it can provide more excellent routing plan.Provided among Fig. 4 at present embodiment, simulation time under 2 hours to 24 hours various situations, the ratio of the switching number of the optimum complete trails that routing algorithm of the present invention and FSA routing algorithm provide.Be in the routing Design of index to switch number, it is less that the complete trails that algorithm of the present invention provides switches number, more excellent than the path that FSA algorithm provides.Therefore the advantage root of routing algorithm of the present invention, can provide more excellent route equally in the continuous state emulation to the satellite link network dynamic topology under other index, do not repeat them here.

Claims (1)

1. satellite link network continuous state route designing method, thereby it is characterized in that by register the complete dynamic topology differentiation information of moment preservation network that link switches in the time between connection and non-connected state in whole simulation, provide more excellent route, may further comprise the steps:

Step 1, set up the Link State switching table; Record the Origin And Destination that each bar link connecting section of " 1 " and " 1 " mark is also used in all Link State conversions constantly respectively in time in whole simulation:

L _ij＝Link _ij{S _i,S _j,t ₀,'1',t ₁,'-1',t ₃,'1',…,t _n,'1',t _n+1,'-1'} (1)

In the formula, S _iAnd S _jBe satellite or topocentric numbering, L _IjBe S _iWith S _jBetween link, Link _Ij... be link L _IjInformation set, t ₀..., t _N+1Be Link State switching instant point, link L _IjCan be expressed as at the connecting section of whole simulation in the time:

L(S _i,S _j)＝[t ₀ t ₁]∪[t ₃ t ₄]∪…∪[t _n t _n+1] (2)

Step 2, search and record path; Whole simulation in the time by given communication line starting point and terminal point searching route, the record path connecting section, i.e. initial moment in path life-span and stopping constantly, and by the numbering of the satellite that from circuit starting point journal path to terminal, comprises:

P _i＝Path _i{S _i1,…S _in,t _i0,'1',t _i1,'-1'} (3)

In the formula, P _iBe the i paths that searches, t _I0And t _I1The initial sum that is respectively the path life-span stops constantly, and this two moment can be determined by the common factor of the connecting section of the link that comprises in the path:

$\left[\begin{array}{cc}{t}_{i0}& t_{i1}\end{array}\right]\⊆L_{i1,i2}\∩L_{i2,i3}\∩\·\·\·\∩L_{i(n-1),\mathrm{in}}---\left(4\right)$

The more than interval of right-hand member common factor possibility in the formula is with each interval connecting section storage as an independent pathway of occuring simultaneously, [t _I0t _I1] therefore only get one of them interval of occuring simultaneously, other interval saves as new route, deposits all independent pathways in the path storehouse;

Step 3, carry out path filtering; From the second path, search a new route P at every turn _i, then in the storehouse, path, carry out two-way approach and filter, at first check whether there is a paths P in the storehouse, path _k, make following two conditions set up simultaneously:

（1） $\left[\begin{array}{cc}{t}_{k0}& t_{k1}\end{array}\right]\⊇\left[\begin{array}{cc}{t}_{i0}& t_{i1}\end{array}\right]$

（2） ${\{S}_{k1},\·\·\·,S_{\mathrm{km}}\}\⋐\{S_{i1},\·\·\·,S_{\mathrm{in}}\}$

If then abandon path P _i, otherwise with P _iDeposit the storehouse, path in, and check that conversely arbitrary in the storehouse, path is removed P _iOutside path P _kWhether satisfy simultaneously:

（1） $\left[\begin{array}{cc}{t}_{k0}& t_{k1}\end{array}\right]\⊆\left[\begin{array}{cc}{t}_{i0}& t_{i1}\end{array}\right]$

（2） $\{S_{k1},\·\·\·,S_{\mathrm{km}}\}\⊃\{S_{i1},\·\·\·,S_{\mathrm{in}}\}$

If, then with path P _kFrom the storehouse, path, delete;

Step 4, carry out complete trails and integrate; Each paths is used as a node, in the storehouse, path, use the Dijkstra shortest path first and carry out the path series connection, finish the integration of complete trails, wherein, path value in the dijkstra's algorithm replaces with corresponding routing optimality index, when the calculation optimization index, use integration method according to the dynamic evolution information calculations of linkage length

P _i＝Path _i{S _i1,…,S _in,t _i0,'1',t _i1,'-1',l _i,j} (5)

In the formula, l _iBe the optimization desired value in this path, j is the numbering in its last path that is connected.

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