CN103369670A - Improved DV-hop (distance vector-hop) location method based on hop count optimization - Google Patents

Abstract

The invention discloses an improved DV-hop (distance vector-hop) location method based on hop count optimization. The method comprises the following steps of firstly screening anchor nodes, and selecting an anchor node with unknown distance and less node hop count to participate in the location computation; and meanwhile, optimizing a location coordinate value obtained through the combinational computation of different anchor nodes, carrying out the selection according to the sum of the location coordinate values and an absolute difference value of the hop count between the unknown node and each anchor node, and adopting the coordinate value with the minimal sum of the absolute value as a final location coordinate of the unknown node. Due to the adoption of the location method, not only can the accuracy of average hop distance be improved, but also the combinational topological situation of the anchor nodes can be prevented from influencing the precision of the location coordinate.

Description

A kind ofly preferably improve the DV-Hop localization method based on jumping figure

Technical field

The present invention relates to a kind ofly preferably improve the DV-Hop localization method based on jumping figure, belong to the wireless sensor network technology field.

Background technology

Wireless sensor network is comprised of the cheap microsensor node that is deployed in a large number in the monitored area.The mutually collaboratively perception of each node, gather the information in the monitored area, and send to the user by wireless mode.Because do not know that in many practical applications the data of positional information are often meaningless, so in the numerous researchs of wireless sensor network, node locating is must obligato link.Because node energy is limited, the location algorithm of therefore design high position precision, need not the additional hardware condition, amount of calculation is moderate has realistic meaning.

Whether according to actual distance can be divided into location algorithm based on two kinds of the location of the location of range finding and non-range finding between the needs measured node.Location algorithm based on range finding need to be by distance or the angle information between extra hardware unit measured node, and then the position of the computing nodes such as use trilateration, triangulation.Typically the location algorithm based on range finding has: RSSI, TOA, TDOA, AOA etc.Only need to utilize between node based on the location algorithm of non-range finding the information such as jumping figure and in addition simple operation just can estimate internodal distance, main algorithm includes barycenter, convex programming, DV-Hop, MDS-MAP etc.Based on the algorithm positioning accuracy of range finding than high based on the algorithm of non-range finding, but the energy consumption of required cost, node also can be larger, based on the location algorithm of non-range finding by research with improve, much can satisfy the location requirement of wireless sensor network.

In the algorithm based on non-range finding, utilize DV-Hop (the Distance Vector Hop) algorithm of jumping figure between distance vector route and node to realize simple, the position fixing process of whole algorithm just can obtain the elements of a fix of unknown node by Average hop distance, jumping figure and the method for calculating and locating of node, the algorithm cost is low, calculating and communication overhead are moderate, lower to hardware requirement, be applicable to distributed network, favorable expandability.But the DV-Hop algorithm also still exists the some shortcomings part, only utilizes corrected value from its nearest anchor node as Average hop distance such as unknown node in the algorithm, can make internodal estimated distance and final location Calculation produce larger error.The anchor node combination of choosing at random when location Calculation also can cause larger impact to positioning accuracy.

The core of DV-Hop algorithm is to utilize internodal estimated distance to replace the actual measurement distance, estimated distance then is to multiply each other to obtain by jumping figure and Average hop distance between unknown node and the anchor node, afterwards the elements of a fix of the coordinate Calculation unknown node by internodal estimated distance and anchor node.The DV-Hop algorithm is comprised of three phases:

The first step: obtain internodal minimum hop count

Anchor node sends the self-position information tuple that comprises hop count field in the mode of broadcasting to neighbor node, the initial value of hop count field is made as 0, receiving node receives after this information tuple and jumping figure to be added 1 and record position and the jumping figure of this anchor node, this tuple is transmitted to its neighbor node.If node receives a plurality of tuples from same beaconing nodes, then node only keeps the tuple information of jumping figure minimum, and each node can both be recorded oneself to the minimum hop count of each anchor node in the network by this method, and obtains the positional information of anchor node.

Second step: the distance between estimation unknown node and the anchor node

Each anchor node is all the other anchor node coordinates and the minimum hop count between them in obtaining network, calculates the Average hop distance of oneself, is also referred to as the network calibration value:

$C_i=\frac{\underset{i,j=1,i\≠j}{\overset{m}{\mathrm{\Σ}}}\sqrt{{(x_i-x_j)}^2+{(y_i-y_j)}^2}}{\underset{i,j=1,i\≠j}{\overset{m}{\mathrm{\Σ}}}{h}_{\mathrm{ij}}}---\left(1\right)$

In the formula, (x _i, y _i), (x _j, y _j) be the coordinate of anchor node i and j; h _IjIt is anchor node i and the j (jumping figure between the i ≠ j).

The Average hop distance that each anchor node calculates oneself is broadcast in the network as corrected value.Each unknown node only receives first corrected value of acquisition, and with its Average hop distance as self, and the corrected value of receiving after abandoning.After the Average hop distance that obtains self, unknown node multiplies each other to calculate distance with each anchor node by Average hop distance and the jumping figure to each anchor node that obtains before.

The 3rd step: calculate the unknown node coordinate

Unknown node obtains utilizing trilateration to calculate the coordinate of unknown node after the estimated distance from three or above different anchor nodes.

The advantage of DV-Hop location algorithm is that computational process is simple, and hsrdware requirements are lower, but also exists the larger shortcoming of position error.By analysis and research, the source that error produces mainly is: anchor node combinatorial topology situation is uncontrollable.Anchor node is more in the network, and it is more reasonable to distribute, and then positioning accuracy is also just relatively high.But when being applied in the middle of the actual environment based on the characteristics of wireless sensor network, sensor node is sown in certain zone often at random, this anchor node wherein very possible extremely irrational situation that occurs that distributes.On the other hand, owing to be subject to cost impact, it also is infeasible disposing in a large number anchor node.So in this case, the topology of anchor node will have a huge impact for the positioning accuracy of finish node, and the unknown node that more has some to be distributed in network edge can be owing to receive the situation that anchor node information is fewer and may occur locating.

For more existing relevant the improving one's methods of head it off are suggested, mostly these methods are to select to participate in afterwards calculating by the triangle that forms according to the distribution situation of anchor node in the network.These improvement can both improve the positioning accuracy of DV-Hop algorithm unknown node to a certain extent, but also all still existing some shortcomings, mainly is because the anchor node topology situation of selecting to participate in location Calculation has larger impact to positioning result by researching and analysing.Position error has significant lifting when occurring when the anchor node combination conllinear of selected participation location Calculation or near situations such as conllinear.

The present invention analyzes the not high reason of DV-Hop algorithm positioning accuracy, finds source of error to improve accordingly, and proposes preferred DV-Hop (Selected DV-Hop, SDV-Hop) localization method based on jumping figure with this.

Summary of the invention

Goal of the invention: for problems of the prior art, the invention provides and a kind ofly preferably improve the DV-Hop localization method based on jumping figure.

Technical scheme: a kind ofly preferably improve the DV-Hop localization method based on jumping figure, at first carry out certain screening for anchor node, the less anchor node of chosen distance unknown node jumping figure participates in location Calculation; The elements of a fix value of calculating gained for different anchor node combinations is simultaneously carried out preferably, select to the size of the poor absolute value sum of each anchor node jumping figure according to these elements of a fix values and unknown node, the coordinate figure of the sum that takes absolute value minimum is as the final elements of a fix of unknown node.

Preferred anchor node: the anchor node after the described screening and the jumping figure between the unknown node are less than the mean value of all anchor nodes and this unknown node jumping figure; The reason of considering like this is when the nodes skewness, the jumping figure of anchor node and unknown node is more, the possibility of the jumping section path deviation straight line between them is larger, and consequent estimated distance error is also larger, so first anchor node is carried out certain screening.Select part anchor node participation afterwards the location Calculation less with the unknown node jumping figure, not only can avoid in advance the accumulation of error on the afterwards impact of location Calculation, also can reduce certain amount of calculation simultaneously.

The preferred orientation coordinate figure: with the measured value of different anchor nodes combination by the unknown node that calculates all as candidate's coordinate in the network, these candidate's coordinates are larger to the poor absolute value sum of an anchor node jumping figure to jumping figure and this unknown node self of each anchor node, this candidate's coordinate is more away from the real coordinate of unknown node so, and namely error is larger.Otherwise the jumping figure and this unknown node self that arrive each anchor node when candidate's coordinate are less to the poor absolute value sum of an anchor node jumping figure, and this candidate's coordinate is more near the true coordinate of unknown node so, and namely error is less, and positioning accuracy is higher.If n unknown node namely arranged in the network, m anchor node is for unknown node U _x, x=1,2 ..., n, it is with m anchor node three combination results at random

Kind of result all uses coordinate that trilateration calculates as U _xCandidate's elements of a fix, be designated as E _k,

And with E _kWith U _xTo the poor absolute value summation of each anchor node jumping figure, be designated as Diff _k, Hop (E in the formula _k, i), hop (U _x, i) be respectively E _kAnd U _xAnd the jumping figure between the anchor node i.With Diff _kMinimum candidate's coordinate figure E _kAs required U _xThe elements of a fix.

Design is because make discovery from observation in the network of a node random distribution like this, if node has identical communication radius, jumping figure and euclidean distance between node pair have following relationship characteristic between node so: if two unknown node wide aparts, these two unknown node are very large to the poor absolute value sum of each anchor node jumping figure so, and vice versa.If two unknown node close proximity, these two unknown node are very little to the poor absolute value sum of each anchor node jumping figure so, and vice versa.

Preferably improve the DV-Hop localization method based on jumping figure, concrete step is as follows:

(1) nodes obtains minimum hop count with other each node by distance vector routing protocol;

(2) anchor node calculate self corrected value and inundation to network, each unknown node receives only at first the corrected value that obtains and as oneself Average hop distance;

(3) mean value of jumping figure between unknown node calculating and all anchor nodes;

(4) each anchor node will be own and unknown node between jumping figure and step (3) in the mean value of trying to achieve compare, if jumping figure greater than mean value then cast out this anchor node, enters step (5) otherwise then preserve this anchor node;

(5) unknown node by Average hop distance and jumping figure multiply each other obtain and step (4) in estimated distance between the anchor node that preserves;

(6) per three random groups merging utilizes the estimated distance of step (5) gained to calculate candidate's elements of a fix value by trilateration for the anchor node that preserves in the step (4);

(7) candidate's elements of a fix value of the combination of different anchor nodes being calculated gained is by trying to achieve the jumping figure of this candidate's coordinate and each anchor node with the information of its nearest anchor node in position, afterwards these jumping figures and unknown node are asked poor absolute value sum to the jumping figure of each anchor node, and according to size select, choose the coordinate of absolute value sum minimum as the final elements of a fix of unknown node, the location of finishing all unknown node.

Beneficial effect: compared with prior art, provided by the inventionly preferably improve the DV-Hop localization method based on jumping figure, anchor node in the network is carried out certain screening, all anchor nodes are optimized from the participation location Calculation of unknown node close to according to the jumping figure size, when avoiding the accumulation of error, reduce amount of calculation.At last, these anchor nodes are calculated the coordinate of trying to achieve by various combination to carry out preferably, select to the size of the poor absolute value sum of each anchor node jumping figure according to these candidate's elements of a fix and unknown node, the coordinate of the sum that takes absolute value minimum reaches the purpose that the selected elements of a fix and required node actual coordinate approach the most as the final elements of a fix of unknown node.The present invention has not only improved the accuracy of Average hop distance, can avoid anchor node combinatorial topology situation for the impact of elements of a fix accuracy simultaneously.

Description of drawings

Fig. 1 is the method flow diagram of the embodiment of the invention;

Fig. 2 is node distribution map schematic diagram;

Fig. 3 is the far and near graph of a relation of measured value and anchor node;

Fig. 4 is the Signal Coverage Percentage comparison diagram;

Fig. 5 is average position error and unknown node Figure of the quantitative relationship;

Fig. 6 is average position error and anchor node Figure of the quantitative relationship;

Fig. 7 is average position error and communication radius graph of a relation.

Embodiment

Below in conjunction with specific embodiment, further illustrate the present invention, should understand these embodiment only is used for explanation the present invention and is not used in and limits the scope of the invention, after having read the present invention, those skilled in the art all fall within the application's claims limited range to the modification of the various equivalent form of values of the present invention.

As shown in Figure 1, preferably improve the DV-Hop localization method based on jumping figure, concrete step is as follows:

(1) nodes obtains minimum hop count with other each node by distance vector routing protocol;

(2) anchor node calculate self corrected value and inundation to network, each unknown node receives only at first the corrected value that obtains and as oneself Average hop distance;

(3) mean value of jumping figure between unknown node calculating and all anchor nodes;

(4) each anchor node will be own and unknown node between jumping figure and step (3) in the mean value of trying to achieve compare, if jumping figure greater than mean value then cast out this anchor node, enters step (5) otherwise then preserve this anchor node;

(5) unknown node by Average hop distance and jumping figure multiply each other obtain and step (4) in estimated distance between the anchor node that preserves;

(6) per three random groups merging utilizes the estimated distance of step (5) gained to calculate candidate's elements of a fix value by trilateration for the anchor node that preserves in the step (4);

(7) candidate's elements of a fix value of the combination of different anchor nodes being calculated gained is by trying to achieve the jumping figure of this candidate's coordinate and each anchor node with the information of its nearest anchor node in position, afterwards these jumping figures and unknown node are asked poor absolute value sum to the jumping figure of each anchor node, and according to size select, choose the coordinate of absolute value sum minimum as the final elements of a fix of unknown node, the location of finishing all unknown node.If n unknown node namely arranged in the network, m anchor node is for unknown node U _x, x=1,2 ..., n, it is with m anchor node three combination results at random

Kind of result all uses coordinate that trilateration calculates as U _xCandidate's elements of a fix, be designated as E _k,

And with E _kWith U _xTo the poor absolute value summation of each anchor node jumping figure, be designated as Diff _k,

Hop (E in the formula _k, i), hop (U _x, i) be respectively E _kAnd U _xAnd the jumping figure between the anchor node i.With Diff _kMinimum candidate's coordinate figure E _kAs required U _xThe elements of a fix.

Design is because make discovery from observation in the network of a node random distribution like this, if node has identical communication radius, jumping figure and euclidean distance between node pair have following relationship characteristic between node so: if two unknown node wide aparts, these two unknown node are very large to the poor absolute value sum of each anchor node jumping figure so, and vice versa.If two unknown node close proximity, these two unknown node are very little to the poor absolute value sum of each anchor node jumping figure so, and vice versa.Prove by reduction to absurdity with the unknown node among Fig. 2 and anchor node.In Fig. 2, node is randomly dispersed in the zone of 50m * 50m, wherein A ₁, A ₂, A ₃, A ₄Anchor node, U ₁, U ₂..., U ₆Be unknown node, the node communication radius all is 15m.

Prove by reduction to absurdity:

(a) suppose U ₁And U ₆Between these two unknown node apart from apart from each other, but the poor absolute value sum of these two nodes and each anchor node jumping figure is less.

According to the distance vector exchange agreement, node in the network sends the packet that comprises jumping figure information to the mode of neighbor node by controlled inundation, the jumping figure value is set to 0 when beginning, neighbor node receives the jumping figure of recording this node behind this packet and the jumping figure value is added 1 and this bag is sent to its neighbor node again, if node receives a plurality of packets from same node, then only keep of jumping figure minimum, so continuous forwarding until in the network each node can both obtain minimum hop count between own and other node, in this way, each node in the network is the path of determining to arrive all the other nodes with minimum hop count.Node U ₁Obtain in this way to A ₁, A ₂, A ₃, A ₄Minimum hop count be respectively 1,1,3,4, and node U ₆Obtain to A ₁, A ₂, A ₃, A ₄Minimum hop count be respectively 5,5,4,1, U ₁With U ₆To A ₁, A ₂, A ₃, A ₄The poor absolute value sum of jumping figure is | 1-5|+|1-5|+|3-4|+|4-1|=12, as seen they are larger to the poor absolute value sum of each anchor node jumping figure, so hypothesis is false.Therefore when two unknown node apart from each others, the poor absolute value sum of these two unknown node and each anchor node jumping figure is also larger so.

(b) suppose U ₁And U ₅The poor absolute value sum of these two unknown node and each anchor node jumping figure is larger, but the close together between these two nodes.

U ₁Jumping figure to each anchor node is respectively 1,1,3,4, U ₅Jumping figure to each anchor node is 4,4,3,1, U ₁And U ₅The absolute value sum poor to each anchor node jumping figure be | 1-4|+|1-4|+|3-3|+|4-1|=9 is relatively large.Because in the identical situation of node communication radius, the neighbor node communication of close together between each node is merely able to it, so when two nodes are larger to the poor absolute value sum of each anchor node jumping figure, illustrate that the jumping figure between these two nodes is also relatively many, also can be larger thereby jump segment distance.From figure, also can find out U ₁And U ₅Between also apart from each other of distance, supposing is false.Therefore, the absolute value sum poor when two unknown node and each anchor node jumping figure is larger, and these two nodes are far away.

(c) suppose U ₁And U ₂Distance between these two unknown node is at a distance of nearer, but the poor absolute value sum of these two nodes and each anchor node jumping figure is larger.

According to the distance vector exchange agreement, node U ₁Obtain to A ₁, A ₂, A ₃, A ₄Minimum hop count be respectively 1,1,3,4, and node U ₂Obtain to A ₁, A ₂, A ₃, A ₄Minimum hop count be respectively 1,1,2,3, U ₁With U ₂To A ₁, A ₂, A ₃, A ₄The poor absolute value sum of jumping figure is | 1-1|+|1-1|+|3-2|+|4-3|=2, as seen they are less to the poor absolute value sum of each anchor node jumping figure, so hypothesis is false.Therefore when two unknown node are nearer apart, the poor absolute value sum of these two unknown node and each anchor node jumping figure is also less so.

(d) suppose U ₄And U ₅The poor absolute value sum of these two unknown node and each anchor node jumping figure is less, but distant between these two nodes.

U ₄Jumping figure to each anchor node is respectively 3,3,2,1, U ₅Jumping figure to each anchor node is 4,4,3,1, U ₄And U ₅The absolute value sum poor to each anchor node jumping figure be | the 3-4|+|3-4|+|2-3|+|1-1|=3 less.In the identical situation of node communication radius, each node is merely able to directly and node communication within its communication radius, so when two nodes to the poor absolute value sum of each anchor node jumping figure hour, illustrate that the jumping figure between these two nodes is also relatively less, therefore distance also can be nearer.From figure, also can find out U ₄And U ₅Between distance also at a distance of nearer, supposing is false.Therefore, the absolute value sum poor when two unknown node and each anchor node jumping figure is less, and these two nodes are nearer.

Card is finished.

For above-mentioned feature is described better, in table 1, listed the jumping figure of each unknown node to all anchor nodes, table 2 has then provided U ₁With jumping figure poor absolute value sum and the U of all unknown node to anchor node ₁And the actual range between other unknown node.From these two tables, can find out when internodal distance larger, two nodes are also larger to the poor absolute value sum of each anchor node jumping figure.

The jumping figure of the different unknown node of table 1. and anchor node

Unknown node	And jumping figure [A between the anchor node 1、A 2、A 3、A 4]
		U 1	[1,1,3,4]
U 2	[1,1,2,3]
		U 3	[2,2,1,2]
U 4	[3,3,2,1]
		U 5	[4,4,3,1]
U 6	[5,5,4,1]

The relation of the actual range of the poor absolute value sum of jumping figure between them between table 2. node

The fixed value that relies on the such network of internodal jumping figure initially to obtain is selected the elements of a fix of unknown node, can well improve the positioning accuracy of node.In the DV-Hop algorithm, used anchor node preferred and the method for elements of a fix value is called the SDV-Hop algorithm with this.

The below introduces respectively the specific implementation process in preferred anchor node and two steps of preferred orientation coordinate figure:

The first step: preferred anchor node.

Unknown node U _x(x=1,2 ..., n) to the mean value of m anchor node jumping figure can in the hope of:

$\stackrel{\‾}{{\mathrm{hop}}_x}=\frac{\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\mathrm{hop}(x,i)}{m}---\left(2\right)$

Hop (x, i) dactylus point U wherein _xAnd the jumping figure between the anchor node i.

When the jumping figure of anchor node and unknown node during greater than average number of hops, cast out this anchor node, remaining anchor node is participated in the location Calculation of back, this moment, remaining anchor node quantity was designated as m'.

Second step: preferred orientation coordinate figure.

Unknown node U _xUtilize the jumping figure of Average hop distance that the first step obtains and m' anchor node to multiply each other and acquire the estimated distance of m' anchor node.Then per three random combines of these anchor nodes are total

Plant various combination, then these anchor nodes are used in combination trilateration and calculate unknown node U _xEstimation elements of a fix value also total

Kind, be designated as Wherein $k=\mathrm{1,2},...,C_{m^{\′}}^3.$

Obtaining the estimated coordinates value

Afterwards, itself and each anchor node A _r(r=1,2 ..., distance m) just can be tried to achieve by formula (3), is designated as

$D_{x,r}^k=\sqrt{{(x^k-x_r)}^2+{(y^k-y_r)}^2}---\left(3\right)$

In the formula, (x ^k, y ^k) expression

Coordinate figure, (x _r, y _r) expression anchor node A _rCoordinate figure.

Because

Can only obtain each anchor node A _rCorrected value C _rAnd anchor node A _rTo other arbitrary anchor node A _t(t=1,2 ..., every hop distance m) is designated as dhop _{R, t}, therefore

Every hop distance to anchor node Value need to be by considering C _rAnd dhop _{R, t}Obtain.By considering distance

The anchor node A that the position is nearest _Near, according to A _NearWith

The distance of distance is considered two kinds of situations.

As shown in Figure 3, U among the figure _xBe the unknown node physical location,

For the estimated position, A _NearFor with

The anchor node that approaches the most.

In Fig. 3 (a), A _NearWith

Distance within the network node communication radius, A _NearWith

Distance at a distance of very near, in this case, A _NearWith A _rEvery hop distance dhop _{Near, r}Just can be used as

To anchor node A _rEvery hop distance

In Fig. 3 (b), A _NearWith

Apart from apart from each other, outside the network node communication radius, this moment A _NearWith A _rEvery hop distance dhop _{Near, r}Just can not conduct

To anchor node A _rEvery hop distance

Can only use A _rCorrected value C _rReplace.

Sum up two kinds of node distribution situations among the figure, To anchor node A _rEvery hop distance

Can obtain:

${\mathrm{dhop}}_{x,r}^k=\left\{\begin{array}{cc}{\mathrm{dhop}}_{\mathrm{near},r}& d_{\mathrm{near}}<\mathrm{Range}\\ C_r& d_{\mathrm{near}}>\mathrm{Range}\end{array}\right.---\left(4\right)$

In the formula, d _NearE _xTo anchor node A _NearDistance, Range is the communication radius of nodes.

Obtaining

With each anchor node A _rDistance

And the every hop distance between them

Afterwards, just can calculate

To the jumping figure between each anchor node.

$h_{x,r}^k=\frac{D_{x,r}^k}{{\mathrm{dhop}}_{x,r}^k}---\left(5\right)$

At last will

And U _xJumping figure hop with each anchor node _{X, r}Ask poor absolute value sum by formula (6).

${\mathrm{Diff}}_x^k=\underset{r=1}{\overset{m^{\&prime;}}{\mathrm{\&Sigma;}}}|h_{x,r}^k-{\mathrm{hop}}_{x,r}|---\left(6\right)$

When

Value less, this just is described

With U _xDistance more approaching.For The combination of kind anchor node obtains

Get wherein minimum value: $\min \left\{{\mathrm{Diff}}_x^k\right\},k=\mathrm{1,2},...,C_{m^{\&prime;}}^3,$ And this value is corresponding

As U _xThe elements of a fix.

Analysis of simulation result

In order to verify validity of the present invention, carry out experiment simulation for SDV-Hop algorithm and DV-Hop algorithm, node is randomly dispersed in the zone of 100m * 100m.From node localization coverage, the quality between the average position error explanation algorithm under different anchor node numbers, unknown node number, the communication radius.

1 Signal Coverage Percentage

The unknown node sum is set to 100 in the network, and the node communication radius is made as 20m, and the anchor node number is increased to 40 from 10, and algorithm simulating is asked the mean value of node localization coverage for 100 times.

As can be seen from Figure 4 two kinds of algorithm Signal Coverage Percentages all can increase along with the increase of anchor node quantity.All unknown node can all be finished the location when SDV-Hop algorithm was increased to 40 in anchor node quantity, and the DV-Hop algorithm still has unknown node can not finish the location.This is because the situation that the node that SDV-Hop can avoid the combination of bad anchor node topology to cause by choose reasonable anchor node and the elements of a fix well can't be located.

The relation of 2 average position errors and unknown node quantity

Fig. 5 has compared the quantity of unknown node in the certain situation of anchor node quantity to the impact of average position error.Anchor node quantity is fixed as 20 in the emulation, and the quantity of unknown node is incremented to 400 from 100.As seen from Figure 5 along with the increase of unknown node sum, average position error all increases to some extent, but the SDV-Hop algorithm is considered the distribution situation of anchor node, and elements of a fix value is selected, and therefore average position error has had certain reduction than DV-Hop algorithm.

The relation of 3 average position errors and anchor node quantity

The unknown node number is fixed as 100 in the emulation, and beaconing nodes quantity is incremented to 40 from 10, and the node communication radius is 20m, relatively uses the average position error of four kinds of algorithm gained, and experimental result as shown in Figure 7.

As can be seen from Figure 6, when anchor node quantity is increased to 25 these processes from 10, average position error descends clearly, and along with further increasing of anchor node quantity, average position error tends towards stability.This is because when anchor node quantity increases, unknown node can select the scope of anchor node to increase, after anchor node is increased to some in the network, the estimated distance error of unknown node and anchor node also tends towards stability, so each unknown node position error tends towards stability, the average position error of network only has small size decline.The SDV-Hop algorithm is owing to consider the situation that anchor node in the network distributes and that the result that different anchor nodes combinations are drawn carried out is preferred, so along with the increase of anchor node quantity, this advantage of improving one's methods is also more for obviously.

The relation of 4 average position errors and node communication radius

In the certain situation of number of nodes, the communication radius of comparison node is on the impact of average position error.In the test, the unknown node number is 100, and the quantity of anchor node is 20, and the communication radius of node is incremented to 40m from 10m.

As can be seen from Figure 7, when the communication radius of nodes became large, the neighbor node number of each node can increase, and that is to say that the chance of the intercommunication of node increases.Like this in the algorithm unknown node and anchor node between jumping figure also can reduce, the possibility of the jumping section path deviation straight line between them because jumping figure reduce also can reduce, so the error of estimated distance will descend to some extent between unknown node and the anchor node, thereby reduced the average position error of all nodes in the final network.The anchor node topology situation drops to minimum for the impact of positioning accuracy among the present invention, so better effects if.

Claims (5)

1. one kind is preferably improved the DV-Hop localization method based on jumping figure, it is characterized in that: at first screen for anchor node, the less anchor node of chosen distance unknown node jumping figure participates in location Calculation; The elements of a fix value of calculating gained for different anchor node combinations is simultaneously carried out preferably, select to the size of the poor absolute value sum of each anchor node jumping figure according to these elements of a fix values and unknown node, the coordinate figure of the sum that takes absolute value minimum is as the final elements of a fix of unknown node.

2. as claimed in claim 1ly preferably improve the DV-Hop localization method based on jumping figure, it is characterized in that: the anchor node after the described screening and the jumping figure between the unknown node are less than the mean value of all anchor nodes and this unknown node jumping figure.

3. as claimed in claim 1ly preferably improve the DV-Hop localization method based on jumping figure, it is characterized in that:

Screen for anchor node and to comprise the steps:

(1) nodes obtains minimum hop count with other each node by distance vector routing protocol;

(2) anchor node calculate self corrected value and inundation to network, each unknown node receives only at first the corrected value that obtains and as oneself Average hop distance;

(3) mean value of jumping figure between unknown node calculating and all anchor nodes;

(4) each anchor node will be own and unknown node between jumping figure and step (3) in the mean value of trying to achieve compare, if jumping figure greater than mean value then cast out this anchor node, otherwise then preserve this anchor node.

4. as claimed in claim 3ly preferably improve the DV-Hop localization method based on jumping figure, it is characterized in that:

Elements of a fix value is preferably included following steps:

Unknown node by Average hop distance and jumping figure multiply each other obtain and step (4) in estimated distance between the anchor node that preserves;

Per three random groups merging utilizes the estimated distance between the anchor node to calculate candidate's elements of a fix value by trilateration for the anchor node that preserves in the step (4);

Candidate's elements of a fix value of the combination of different anchor nodes being calculated gained is by trying to achieve the jumping figure of this candidate's coordinate and each anchor node with the information of its nearest anchor node in position, afterwards these jumping figures and unknown node are asked poor absolute value sum to the jumping figure of each anchor node, and according to size select, choose the coordinate of absolute value sum minimum as the final elements of a fix of unknown node, the location of finishing all unknown node.

5. as claimed in claim 4ly preferably improve the DV-Hop localization method based on jumping figure, it is characterized in that: if n unknown node arranged in the network, m anchor node is for unknown node U _x, x=1,2 ..., n, it is with m anchor node three combination results at random

Kind of result all uses coordinate that trilateration calculates as U _xCandidate's elements of a fix, be designated as E _k, k=1,2 ..., And with E _kWith U _xTo the poor absolute value summation of each anchor node jumping figure, be designated as Diff _k,

Hop (E in the formula _k, i), hop (U _x, i) be respectively E _kAnd U _xAnd the jumping figure between the anchor node i is with Diff _kMinimum candidate's coordinate figure E _kAs required U _xThe elements of a fix.

Images