CN103810358A - Technology for evaluating efficiency of constellation satellite communication system - Google Patents

Abstract

In order to directly and visually evaluate efficiency of a constellation satellite communication system, and select a constellation system scheme which can best meet actual requirements and long-term development requirements to provide powerful decision support, the invention discloses a technology for evaluating the efficiency of the constellation satellite communication system. The technology includes the steps that firstly, an efficiency evaluation index system of the constellation satellite communication system is determined through a Delphi expert consultation method; secondly, weights of efficiency evaluation indexes of the constellation satellite communication system are determined through an analytic hierarchy process; eventually, the efficiency of the constellation satellite communication system is evaluated through an ADC efficiency evaluation model.

Description

Constellation satellite communication system measures of effectiveness technology

Technical field

The present invention relates to constellation satellite communication system measures of effectiveness technology.

Background technology

In recent years, the development of terrestrial cellular wireless network is swift and violent, makes people's information interchange more convenient.But due to the impact of the factors such as geographical environment, China has the ground network in a lot of areas not yet to cover maybe and cannot cover, constellation satellite communication system can conveniently realize the seamless covering of earth surface, improve rapidly these regional communication conditions with its advantageous advantage, without the huge input of ground communication facilities.

Constellation satellite communication system is a complex structure, invests huge large scale system, and that its conceptual design comprises is interrelated, the many factors of restriction each other.From different angles, consider the impact of many factors on the practical usefulness of constellation satellite communication system, certainly will make scheme Design be full of diversity.Different design proposals makes to have systems technology feature separately, and effect is different, and How to choose can practical requirement, meets the constellation systems scheme of long term growth, avoids as far as possible great investment error, is the purpose of Effectiveness Evaluation.Under this background, the present invention proposes constellation satellite communication system measures of effectiveness technology.

ADC model is that American industry circle Weapons Systems Effectiveness advisory committee (WSEIAC) sets up, and obtains widespread use in a lot of fields.ADC model generalization taking into account system can be unavailable, can be unreliable while using and the three large key elements that can satisfy the demands, be a kind of comprehensively, objective synthetic effectiveness evaluation method.Therefore, the evaluation method of the present invention using ADC model as constellation satellite communication system measures of effectiveness.

Summary of the invention

The technical solution adopted in the present invention is: constellation satellite communication system measures of effectiveness technology, its step is as follows.

Step 1: set up constellation satellite communication system assessment indicator system.

By consulting pertinent literature, and sum up the influence factor that affects constellation satellite communication system, organize the authoritative expert of this respect, adopt Delphi expert consulting method to determine constellation satellite communication system assessment indicator system.

Step 2: the weight of determining constellation satellite communication system evaluation index.

Because the structure of constellation satellite communication system assessment indicator system is a multi-level structure, and analytical hierarchy process is processed the algorithms most in use of evaluation index weight in this class architecture just.Therefore, the present invention adopts analytical hierarchy process to determine the weight of constellation satellite communication system evaluation index.

Step 3: data acquisition.

In conjunction with constellation satellite communication system measures of effectiveness index, carry out data acquisition.

Step 4: adopt ADC model to carry out constellation satellite communication system measures of effectiveness.

ADC model formation is

E=ADC

Wherein, A is availability, the probability of expression system different conditions of living in the time starting to execute the task, and computing formula is as follows:

A=[a ₁1-a ₁], wherein a ₁=MTBF/ (MTBF+MTTR).

Here, MTBF is the average valuation of system interval time, and MTTR is mean repair time.

D is reliability matrix, represents known system residing state in the time starting working.If satellite mean failure rate probability is λ, spanning tree threshold value is T, and reliability matrix D can be expressed as:

$D=\left[\begin{array}{cc}1-{\mathrm{\λ}}^{\left(\frac{S-T}{L}\right)}& {\mathrm{\λ}}^{\left(\frac{S-T}{L}\right)}\\ 0& 1\end{array}\right]$

Here,

, L=S/N, N is system number.

C is ability matrix, represents that known system when residing state, completes measuring of assignment of mission in the process of executing the task, and computing formula is as follows:

C=[c ₁c ₂] ^t, c ₁, c ₂represent respectively the probability that under normal and malfunction, system is finished the work, generally task is nonserviceabled lower system cannot finish the work time, c ₂=0.While assessment due to constellation satellite communication system, relate to index many, easily cause the calculation of complex of C.Therefore, in the present invention, index is carried out to linear weighted function, using the index attribute value of the reflection entire system ability obtaining as ability Matrix C.

Here, the index attribute value of entire system ability is:

$c_i=\underset{j=1}{\overset{n}{\mathrm{\Σ}}}{w}_j{x}_{\mathrm{ij}}$

Wherein, w _jbe j (j=1,2 ..., the n) weight of individual constellation satellite communication system evaluation index, x _ijbe i constellation satellite communication system about j (j=1,2 ..., the n) desired value of individual evaluation index.

The invention has the beneficial effects as follows: in conjunction with correlation theory research, proposed constellation satellite communication system assessment technology, through at practice test, shown that the method is reasonable in design, practical, for the assessment of constellation satellite communication system provides good method.Study constellation satellite communication system evaluation index system, analyzed, studied the method for constellation satellite communication system evaluation index weight, for constellation satellite communication planning provides theoretical reference.

Accompanying drawing explanation

Fig. 1 is process flow diagram of the present invention.

Embodiment

As described in Figure 1, constellation satellite communication system measures of effectiveness technology mainly comprises 6 steps: 1) tissue expert, adopts Delphi expert consulting method to determine constellation satellite communication system measures of effectiveness index system; 2) application level analytic approach is determined the weight of constellation satellite communication system measures of effectiveness index; 3) gather related data; 4) through ADC Effectiveness Evaluation Model, constellation satellite communication system usefulness is assessed.Idiographic flow is as follows:

Step 1: set up constellation satellite communication system assessment indicator system.

Organize the expert of constellation satellite communication system aspect, adopt Delphi expert consulting method to set up the assessment indicator system of constellation satellite communication system usefulness, in table 1.

Table 1 constellation satellite communication system index system

Step 2: the weight of determining constellation satellite communication system evaluation index.

Because the structure of constellation satellite communication system assessment indicator system is a multi-level structure, and analytical hierarchy process is processed the algorithm of evaluation index weight in this class architecture just.Therefore, the present invention adopts analytical hierarchy process to determine the weight of constellation satellite communication system evaluation index, and detailed process is as follows.

Step 2.1: expert seeks advice to multidigit, the data of obtaining are weighted on average, determine the judgment matrix of each layer, and result is as follows.

1) judgment matrix of rule layer

$U=\left[\begin{array}{cccc}1& 3& 4& 6\\ 1/3& 1& 1/3& 3\\ 1/4& 3& 1& 3\\ 1/6& 1/3& 1/3& 1\end{array}\right]$

2) judgment matrix of indicator layer, wherein covers, the judgment matrix of access, quality of service and system security is respectively matrix B, C, D, E.

$U_1=\left[\begin{array}{ccc}1& 3& 5\\ 1/3& 1& 1/2\\ 1/5& 2& 1\end{array}\right]$ ， $U_2=\left[\begin{array}{cccc}1& 2& 5& 1/3\\ 1/2& 1& 3& 1/5\\ 1/5& 1/3& 1& 1/7\\ 3& 5& 7& 1\end{array}\right]$ ， $U_3=\left[\begin{array}{cccc}1& 5& 1/3& 3\\ 1/5& 1& 1/7& 1/2\\ 3& 7& 1& 7\\ 1/3& 2& 1/7& 1\end{array}\right]$ ， $U_4=\left[\begin{array}{cccc}1& 1/3& 3& 2\\ 3& 1& 4& 3\\ 1/3& 1/4& 1& 1/2\\ 1/2& 1/3& 2& 1\end{array}\right]$

Step 2.2: calculate above-mentioned judgment matrix U, U ₁, U ₂, U ₃, U ₄maximum characteristic root and corresponding maximal eigenvector, they are normalized respectively, and carry out consistency check, determine the weight of constellation satellite communication system evaluation index, it the results are shown in Table 2.

Table 2 constellation satellite communication system index weights allocation result

Step 3: data acquisition

Because constellation satellite communication system measures of effectiveness index system comprises quantitative target and qualitative index, therefore adopt diverse ways image data for different indexs, concrete evaluation index acquisition mode is in table 3.

Table 3 achievement data acquisition mode

Data after gathering are normalized.

Step 4: adopt ADC model to carry out constellation satellite communication system measures of effectiveness.

ADC model formation is

E=ADC （1）

Wherein, A is availability, the probability of expression system different conditions of living in the time starting to execute the task, and computing formula is as follows:

A=[a ₁ 1-a ₁] （2）

Here a, ₁=MTBF/ (MTBF+MTTR).

Wherein, MTBF is the average valuation of system interval time, and MTTR is mean repair time.

D is reliability matrix, represents known system residing state in the time starting working.If satellite mean failure rate probability is λ, spanning tree threshold value is T, and reliability matrix D can be expressed as:

$D=\left[\begin{array}{cc}1-{\mathrm{\λ}}^{\left(\frac{S-T}{L}\right)}& {\mathrm{\λ}}^{\left(\frac{S-T}{L}\right)}\\ 0& 1\end{array}\right]---\left(3\right)$

Here,

, L=S/N, N is system number.

C is ability matrix, represents that known system when residing state, completes measuring of assignment of mission in the process of executing the task, and computing formula is as follows:

C=[c ₁c ₂] ^t, c ₁, c ₂represent respectively the probability that under normal and malfunction, system is finished the work, generally task is nonserviceabled lower system cannot finish the work time, c ₂=0.While assessment due to constellation satellite communication system, relate to index many, easily cause the calculation of complex of C.Therefore, in the present invention, index is carried out to linear weighted function, using the index attribute value of the reflection entire system ability obtaining as ability Matrix C.

Here, the index attribute value of entire system ability is:

$c_i=\underset{j=1}{\overset{n}{\mathrm{\Σ}}}{w}_j{x}_{\mathrm{ij}}---\left(4\right)$

Wherein, w _jbe j (j=1,2 ..., the n) weight of individual constellation satellite communication system evaluation index, x _ijbe i constellation satellite communication system about j (j=1,2 ..., the n) desired value of individual evaluation index.

In order to verify the performance of algorithm of the present invention, IRIDIUM (Iridium) and GlobalStar (Globalstar) are assessed.Wherein, table 4 is the normalization evaluation index value of these two constellation satellite systems.

Table 4 evaluation index value

Index	Iridium	Globalstar
			Single star coverage rate	1.0	0.83
Link mean down time	0.63	0.72
			The minimum elevation angle that covers	0.85	0.8
Access capacity	0.81	0.76
			Access rate	0.7	0.8
Average turn-on time	0.7	0.85
			Access blocking rate	0.77	0.85
Transmission delay	0.7	0.75
			Cutting off rate	0.75	0.85
Packet loss	0.8	0.82
			The bit error rate	0.8	0.7
Maintainable	0.55	0.65
			Anti-interference	0.6	0.75
Information encryption	0.75	0.65
			Safety certification	0.8	0.7

On this basis, application ADC Effectiveness Evaluation Model is assessed Iridium system and Globalstar system effectiveness.As an example, the present invention provide Iridium system about in ADC Effectiveness Evaluation Model about parameter A, D, the analysis of C, specific as follows:

1) acquisition of parameter A

The mean time between failures (MTBF) of Iridium system is 10 years, and mean time between maintenance MTTR is 0.15, and application of formula (2) obtains the availability matrix of Iridium and is: [0.985,0.015].

2) acquisition of parameter D

By STK emulation, constantly reduce number of satellite, can obtain data shown in table 5:

Table 5 Iridium system coverage rate and satellite damage number relation table

Obviously, in the time that satellite damage reaches 12 stars, single star covers to reduce to 89.66%, approximately there is 10% possibility not have satellite to cover, system state now cannot meet the properties value measuring under normal operating conditions, thereby can, using this as thresholding, be about 9.6% according to rail satellite average year valuation rate.Computing system state transition probability, the result of calculation of Iridium system state transition probability is:

$\mathrm{\ρ}={\left(0.096\right)}^{12/6}=9.2\×{10}^{-3}$

According to the reliable matrix D of the known Iridium system of formula (3) be

$D=\left[\begin{array}{cc}0.9908& 0.0092\\ 0& 1\end{array}\right]$

3) acquisition of parameters C

In associative list 2, about the index evaluation value of Iridium and Globalstar in the weight of constellation satellite communication system measures of effectiveness index and table 4, should formula (4) obtain reflecting the index attribute value P of entire system ability, have:

$P_{\mathrm{Iridium}}=0.8011,P_{\mathrm{Globalstar}}=0.7756$

The ability Matrix C of Iridium system is:

$C=\left[\begin{array}{c}0.8011\\ 0.7756\end{array}\right]$

Application of formula (1), determines that the measures of effectiveness value of Iridium system is: 0.8005.

Equally, according to the desired value about Globalstar system in table 4, application ADC Effectiveness Evaluation Model can determine that the measures of effectiveness value of Globalstar system is 0.769.

Therefore, can find out that through the present invention IRIDIUM comprehensive effectiveness will be higher than GlobalStar comprehensive effectiveness, this result meets generally acknowledges the fact.

Claims (2)

1. constellation satellite communication system measures of effectiveness technology, its concrete steps are as follows: 1) application Delphi expert consulting method is set up constellation satellite communication system measures of effectiveness index system; 2) application level analytic approach is determined constellation satellite communication system measures of effectiveness index weights; 3) application ADC Effectiveness Evaluation Model assessment constellation satellite communication system usefulness.

2. constellation satellite communication system measures of effectiveness technology according to claim 1, its feature, in the feature in conjunction with constellation satellite communication system, has been set up ADC Effectiveness Evaluation Model, that is:

Wherein, 1) A is availability, the probability of expression system different conditions of living in the time starting to execute the task, and computing formula is as follows:

Here, MTBF is the average valuation of system interval time, and MTTR is mean repair time;

2) D is reliability matrix, represents known system residing state in the time starting working, and establishes satellite mean failure rate probability and is

, spanning tree threshold value is T, reliability matrix D can be expressed as:

Here,

, N is system number;

3) C is ability matrix, represents that known system when residing state, completes measuring of assignment of mission in the process of executing the task, and computing formula is as follows:

，

Wherein

represent respectively the probability that under normal and malfunction, system is finished the work, adopt the index attribute value of reflection entire system ability as ability Matrix C,

Here,

be the weight of j constellation satellite communication system evaluation index, be the desired value of i constellation satellite communication system about j evaluation index.

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