1. a kind of UKF of Problem with Some Constrained Conditions WSN node positioning methods, UKF is Unscented kalman filtering, and WSN is wireless sensing
Device network, its job step is:
1) ranging model has two kinds of theoretical model and empirical model, and ranging model uses logarithm-normal distribution in theoretical model
The data that acquisition is tested in experimental situation are carried out processing using gaussian filtering technology and curve fitting technique and determine model by model
In unknown parameter, set up the signal intensity received and indicate RSSI and the relation between;
2) RSSI is converted into distance value using ranging model;Coordinate P is tried to achieve using Maximum-likelihood estimation MLE methodsMLE, coordinate value
For (xMLE,yMLE);If the coordinate of previous moment is P in unknown node adjacent two moment0, coordinate value is (x0,y0);Using R as half
Footpath, P0For the center of circle, make a restrained circle;Choose two beaconing nodes maximum in current time RSSI value and be set to A and B, its coordinate
Respectively (x1,y1) and (x2,y2);Make straight line AP0And BP0, the intersection point with restrained circle is respectively M and N, then sector MP0N constitutes one
Individual coordinates restriction region;The coordinate value for obtaining point M and N respectively using formula below is (xM,yM) and (xN,yN);
<mfenced open = "{" close = "">
<mtable>
<mtr>
<mtd>
<mrow>
<mo>(</mo>
<mi>x</mi>
<mo>-</mo>
<msub>
<mi>x</mi>
<mn>0</mn>
</msub>
<mo>)</mo>
<mo>=</mo>
<mi>k</mi>
<mo>(</mo>
<mi>y</mi>
<mo>-</mo>
<msub>
<mi>y</mi>
<mn>0</mn>
</msub>
<mo>)</mo>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<msup>
<mrow>
<mo>(</mo>
<mi>x</mi>
<mo>-</mo>
<msub>
<mi>x</mi>
<mn>0</mn>
</msub>
<mo>)</mo>
</mrow>
<mn>2</mn>
</msup>
<mo>+</mo>
<msup>
<mrow>
<mo>(</mo>
<mi>y</mi>
<mo>-</mo>
<msub>
<mi>y</mi>
<mn>0</mn>
</msub>
<mo>)</mo>
</mrow>
<mn>2</mn>
</msup>
<mo>=</mo>
<msup>
<mi>R</mi>
<mn>2</mn>
</msup>
</mrow>
</mtd>
</mtr>
</mtable>
</mfenced>
In formula:K is the slope value of straight line;
With M, PMLE、N、P04 points are that summit constitutes a quadrangle, and the center-of-mass coordinate for trying to achieve quadrangle is obtained by initial alignment
Coordinate (x', y');
<mrow>
<msup>
<mi>x</mi>
<mo>&prime;</mo>
</msup>
<mo>=</mo>
<mfrac>
<mn>1</mn>
<mn>4</mn>
</mfrac>
<mrow>
<mo>(</mo>
<msub>
<mi>x</mi>
<mn>0</mn>
</msub>
<mo>+</mo>
<msub>
<mi>x</mi>
<mi>M</mi>
</msub>
<mo>+</mo>
<msub>
<mi>x</mi>
<mrow>
<mi>M</mi>
<mi>L</mi>
<mi>E</mi>
</mrow>
</msub>
<mo>+</mo>
<msub>
<mi>x</mi>
<mi>N</mi>
</msub>
<mo>)</mo>
</mrow>
</mrow>
<mrow>
<msup>
<mi>y</mi>
<mo>&prime;</mo>
</msup>
<mo>=</mo>
<mfrac>
<mn>1</mn>
<mn>4</mn>
</mfrac>
<mrow>
<mo>(</mo>
<msub>
<mi>y</mi>
<mn>0</mn>
</msub>
<mo>+</mo>
<msub>
<mi>y</mi>
<mi>M</mi>
</msub>
<mo>+</mo>
<msub>
<mi>y</mi>
<mrow>
<mi>M</mi>
<mi>L</mi>
<mi>E</mi>
</mrow>
</msub>
<mo>+</mo>
<msub>
<mi>y</mi>
<mi>N</mi>
</msub>
<mo>)</mo>
</mrow>
</mrow>
3) using the coordinate of unknown node as the state variable of system, with RSSI value as observation, using ranging model as observation
Equation, sets up adaptive UKF filtering systems;
3.1) state equation:
Xk+1=f (Xk)+wk=AXk+wk
In formula:F () is nonlinear function,For state-transition matrix, Xk=[xk,yk]ΤRepresent that kth moment is
System state stochastic variable, wkFor systematic procedure noise, its average is zero, and covariance is Qk;
3.2) observational equation:
Yk,i=h (Xk)+vk=Pr(dk,i)
Pr(dk,i)=Pr(d0)-10·θ·log(dk,i)+vk
In formula:H () is nonlinear function,Represent unknown node and i-th beaconing nodes it
Between distance, Pr(dk,i) for the reception RSSI value of i-th beaconing nodes, Pr(d0) it is d0Reception RSSI value during=1m, Yk,iFor
Systematic perspective measurement is the reception RSSI value of beaconing nodes, vkFor observation noise, covariance is Rk, θ is path-loss factor;
4) standard UKF algorithms are realized:
4.1) initialize:
<mfenced open = "{" close = "">
<mtable>
<mtr>
<mtd>
<msub>
<mover>
<mi>X</mi>
<mo>^</mo>
</mover>
<mn>0</mn>
</msub>
<mo>=</mo>
<mi>E</mi>
<mo>&lsqb;</mo>
<msub>
<mi>X</mi>
<mn>0</mn>
</msub>
<mo>&rsqb;</mo>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<msub>
<mi>P</mi>
<mn>0</mn>
</msub>
<mo>=</mo>
<mi>E</mi>
<mo>&lsqb;</mo>
<mrow>
<mo>(</mo>
<msub>
<mi>X</mi>
<mn>0</mn>
</msub>
<mo>-</mo>
<msub>
<mover>
<mi>X</mi>
<mo>^</mo>
</mover>
<mn>0</mn>
</msub>
<mo>)</mo>
</mrow>
<msup>
<mrow>
<mo>(</mo>
<msub>
<mi>X</mi>
<mn>0</mn>
</msub>
<mo>-</mo>
<msub>
<mover>
<mi>X</mi>
<mo>^</mo>
</mover>
<mn>0</mn>
</msub>
<mo>)</mo>
</mrow>
<mi>T</mi>
</msup>
<mo>&rsqb;</mo>
</mrow>
</mtd>
</mtr>
</mtable>
</mfenced>
4.2) sampling point is calculated:
<mfenced open = "{" close = "">
<mtable>
<mtr>
<mtd>
<mrow>
<msubsup>
<mi>&chi;</mi>
<mrow>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
<mrow>
<mo>(</mo>
<mn>0</mn>
<mo>)</mo>
</mrow>
</msubsup>
<mo>=</mo>
<msub>
<mover>
<mi>X</mi>
<mo>^</mo>
</mover>
<mrow>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msub>
</mrow>
</mtd>
<mtd>
<mrow></mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<msubsup>
<mi>&chi;</mi>
<mrow>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
<mrow>
<mo>(</mo>
<mi>i</mi>
<mo>)</mo>
</mrow>
</msubsup>
<mo>=</mo>
<msub>
<mover>
<mi>X</mi>
<mo>^</mo>
</mover>
<mrow>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msub>
<mo>+</mo>
<msqrt>
<mrow>
<mo>(</mo>
<mi>L</mi>
<mo>+</mo>
<mi>&lambda;</mi>
<mo>)</mo>
</mrow>
</msqrt>
<msub>
<mrow>
<mo>(</mo>
<msqrt>
<msub>
<mi>P</mi>
<mrow>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msub>
</msqrt>
<mo>)</mo>
</mrow>
<mrow>
<mo>(</mo>
<mi>i</mi>
<mo>)</mo>
</mrow>
</msub>
</mrow>
</mtd>
<mtd>
<mrow>
<mi>i</mi>
<mo>=</mo>
<mn>1</mn>
<mo>,</mo>
<mn>2</mn>
<mo>,</mo>
<mn>...</mn>
<mo>,</mo>
<mi>L</mi>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<msubsup>
<mi>&chi;</mi>
<mrow>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
<mrow>
<mo>(</mo>
<mi>i</mi>
<mo>)</mo>
</mrow>
</msubsup>
<mo>=</mo>
<msub>
<mover>
<mi>X</mi>
<mo>^</mo>
</mover>
<mrow>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msub>
<mo>-</mo>
<msqrt>
<mrow>
<mo>(</mo>
<mi>L</mi>
<mo>+</mo>
<mi>&lambda;</mi>
<mo>)</mo>
</mrow>
</msqrt>
<msub>
<mrow>
<mo>(</mo>
<msqrt>
<msub>
<mi>P</mi>
<mrow>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msub>
</msqrt>
<mo>)</mo>
</mrow>
<mrow>
<mo>(</mo>
<mi>i</mi>
<mo>-</mo>
<mi>L</mi>
<mo>)</mo>
</mrow>
</msub>
</mrow>
</mtd>
<mtd>
<mrow>
<mi>i</mi>
<mo>=</mo>
<mi>L</mi>
<mo>+</mo>
<mn>1</mn>
<mo>,</mo>
<mi>L</mi>
<mo>+</mo>
<mn>2</mn>
<mo>,</mo>
<mn>...</mn>
<mo>,</mo>
<mn>2</mn>
<mi>L</mi>
</mrow>
</mtd>
</mtr>
</mtable>
</mfenced>
4.3) time updates:
<mrow>
<msubsup>
<mi>&chi;</mi>
<mrow>
<mi>k</mi>
<mo>|</mo>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
<mi>x</mi>
</msubsup>
<mo>=</mo>
<mi>f</mi>
<mrow>
<mo>(</mo>
<msubsup>
<mi>&chi;</mi>
<mrow>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
<mi>x</mi>
</msubsup>
<mo>)</mo>
</mrow>
</mrow>
<mrow>
<msub>
<mover>
<mi>X</mi>
<mo>^</mo>
</mover>
<mrow>
<mi>k</mi>
<mo>|</mo>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msub>
<mo>=</mo>
<munderover>
<mo>&Sigma;</mo>
<mrow>
<mi>i</mi>
<mo>=</mo>
<mn>0</mn>
</mrow>
<mrow>
<mn>2</mn>
<mi>L</mi>
</mrow>
</munderover>
<msubsup>
<mi>&omega;</mi>
<mi>i</mi>
<mrow>
<mo>(</mo>
<mi>m</mi>
<mo>)</mo>
</mrow>
</msubsup>
<msubsup>
<mi>&chi;</mi>
<mrow>
<mi>i</mi>
<mo>,</mo>
<mi>k</mi>
<mo>|</mo>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
<mi>x</mi>
</msubsup>
</mrow>
<mrow>
<msub>
<mover>
<mi>P</mi>
<mo>^</mo>
</mover>
<mrow>
<mi>k</mi>
<mo>|</mo>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msub>
<mo>=</mo>
<munderover>
<mo>&Sigma;</mo>
<mrow>
<mi>i</mi>
<mo>=</mo>
<mn>0</mn>
</mrow>
<mrow>
<mn>2</mn>
<mi>L</mi>
</mrow>
</munderover>
<msubsup>
<mi>&omega;</mi>
<mi>i</mi>
<mrow>
<mo>(</mo>
<mi>c</mi>
<mo>)</mo>
</mrow>
</msubsup>
<mo>&lsqb;</mo>
<msubsup>
<mi>&chi;</mi>
<mrow>
<mi>i</mi>
<mo>,</mo>
<mi>k</mi>
<mo>|</mo>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
<mi>x</mi>
</msubsup>
<mo>-</mo>
<msub>
<mover>
<mi>X</mi>
<mo>^</mo>
</mover>
<mrow>
<mi>k</mi>
<mo>|</mo>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msub>
<mo>&rsqb;</mo>
<msup>
<mrow>
<mo>&lsqb;</mo>
<msubsup>
<mi>&chi;</mi>
<mrow>
<mi>i</mi>
<mo>,</mo>
<mi>k</mi>
<mo>|</mo>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
<mi>x</mi>
</msubsup>
<mo>-</mo>
<msub>
<mover>
<mi>X</mi>
<mo>^</mo>
</mover>
<mrow>
<mi>k</mi>
<mo>|</mo>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msub>
<mo>&rsqb;</mo>
</mrow>
<mi>T</mi>
</msup>
<mo>+</mo>
<msub>
<mi>Q</mi>
<mrow>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msub>
</mrow>
<mrow>
<msub>
<mi>Y</mi>
<mrow>
<mi>i</mi>
<mo>,</mo>
<mi>k</mi>
<mo>|</mo>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msub>
<mo>=</mo>
<mi>h</mi>
<mrow>
<mo>(</mo>
<msubsup>
<mi>&chi;</mi>
<mrow>
<mi>i</mi>
<mo>,</mo>
<mi>k</mi>
<mo>|</mo>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
<mi>x</mi>
</msubsup>
<mo>)</mo>
</mrow>
</mrow>
<mrow>
<msub>
<mover>
<mi>Y</mi>
<mo>^</mo>
</mover>
<mrow>
<mi>k</mi>
<mo>|</mo>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msub>
<mo>=</mo>
<munderover>
<mo>&Sigma;</mo>
<mrow>
<mi>i</mi>
<mo>=</mo>
<mn>0</mn>
</mrow>
<mrow>
<mn>2</mn>
<mi>L</mi>
</mrow>
</munderover>
<msubsup>
<mi>&omega;</mi>
<mi>i</mi>
<mrow>
<mo>(</mo>
<mi>m</mi>
<mo>)</mo>
</mrow>
</msubsup>
<msub>
<mi>Y</mi>
<mrow>
<mi>i</mi>
<mo>,</mo>
<mi>k</mi>
<mo>|</mo>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msub>
</mrow>
4.4) measure and update:
<mrow>
<msub>
<mi>P</mi>
<mrow>
<msub>
<mi>y</mi>
<mi>k</mi>
</msub>
<msub>
<mi>y</mi>
<mi>k</mi>
</msub>
</mrow>
</msub>
<mo>=</mo>
<munderover>
<mo>&Sigma;</mo>
<mrow>
<mi>i</mi>
<mo>=</mo>
<mn>0</mn>
</mrow>
<mrow>
<mn>2</mn>
<mi>L</mi>
</mrow>
</munderover>
<msubsup>
<mi>&omega;</mi>
<mi>i</mi>
<mrow>
<mo>(</mo>
<mi>c</mi>
<mo>)</mo>
</mrow>
</msubsup>
<mo>&lsqb;</mo>
<msub>
<mi>Y</mi>
<mrow>
<mi>i</mi>
<mo>,</mo>
<mi>k</mi>
<mo>|</mo>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msub>
<mo>-</mo>
<msub>
<mover>
<mi>Y</mi>
<mo>^</mo>
</mover>
<mrow>
<mi>k</mi>
<mo>|</mo>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msub>
<mo>&rsqb;</mo>
<msup>
<mrow>
<mo>&lsqb;</mo>
<msub>
<mi>Y</mi>
<mrow>
<mi>i</mi>
<mo>,</mo>
<mi>k</mi>
<mo>|</mo>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msub>
<mo>-</mo>
<msub>
<mover>
<mi>Y</mi>
<mo>^</mo>
</mover>
<mrow>
<mi>k</mi>
<mo>|</mo>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msub>
<mo>&rsqb;</mo>
</mrow>
<mi>T</mi>
</msup>
<mo>+</mo>
<msub>
<mi>R</mi>
<mi>k</mi>
</msub>
</mrow>
<mrow>
<msub>
<mi>P</mi>
<mrow>
<msub>
<mi>x</mi>
<mi>k</mi>
</msub>
<msub>
<mi>y</mi>
<mi>k</mi>
</msub>
</mrow>
</msub>
<mo>=</mo>
<munderover>
<mo>&Sigma;</mo>
<mrow>
<mi>i</mi>
<mo>=</mo>
<mn>0</mn>
</mrow>
<mrow>
<mn>2</mn>
<mi>L</mi>
</mrow>
</munderover>
<msubsup>
<mi>&omega;</mi>
<mi>i</mi>
<mrow>
<mo>(</mo>
<mi>c</mi>
<mo>)</mo>
</mrow>
</msubsup>
<mo>&lsqb;</mo>
<msubsup>
<mi>&chi;</mi>
<mrow>
<mi>i</mi>
<mo>,</mo>
<mi>k</mi>
<mo>|</mo>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
<mi>x</mi>
</msubsup>
<mo>-</mo>
<msub>
<mover>
<mi>X</mi>
<mo>^</mo>
</mover>
<mrow>
<mi>k</mi>
<mo>|</mo>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msub>
<mo>&rsqb;</mo>
<msup>
<mrow>
<mo>&lsqb;</mo>
<msub>
<mi>Y</mi>
<mrow>
<mi>i</mi>
<mo>,</mo>
<mi>k</mi>
<mo>|</mo>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msub>
<mo>-</mo>
<msub>
<mover>
<mi>Y</mi>
<mo>^</mo>
</mover>
<mrow>
<mi>k</mi>
<mo>|</mo>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msub>
<mo>&rsqb;</mo>
</mrow>
<mi>T</mi>
</msup>
</mrow>
<mrow>
<msub>
<mi>K</mi>
<mi>k</mi>
</msub>
<mo>=</mo>
<msub>
<mi>P</mi>
<mrow>
<msub>
<mi>x</mi>
<mi>k</mi>
</msub>
<msub>
<mi>y</mi>
<mi>k</mi>
</msub>
</mrow>
</msub>
<msubsup>
<mi>P</mi>
<mrow>
<msub>
<mi>y</mi>
<mi>k</mi>
</msub>
<msub>
<mi>y</mi>
<mi>k</mi>
</msub>
</mrow>
<mrow>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msubsup>
</mrow>
<mrow>
<msub>
<mover>
<mi>X</mi>
<mo>^</mo>
</mover>
<mi>k</mi>
</msub>
<mo>=</mo>
<msub>
<mover>
<mi>X</mi>
<mo>^</mo>
</mover>
<mrow>
<mi>k</mi>
<mo>|</mo>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msub>
<mo>+</mo>
<msub>
<mi>K</mi>
<mi>k</mi>
</msub>
<mrow>
<mo>(</mo>
<msub>
<mi>Y</mi>
<mi>k</mi>
</msub>
<mo>-</mo>
<msub>
<mover>
<mi>Y</mi>
<mo>^</mo>
</mover>
<mrow>
<mi>k</mi>
<mo>|</mo>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msub>
<mo>)</mo>
</mrow>
</mrow>
<mrow>
<msub>
<mi>P</mi>
<mi>k</mi>
</msub>
<mo>=</mo>
<msub>
<mover>
<mi>P</mi>
<mo>^</mo>
</mover>
<mrow>
<mi>k</mi>
<mo>|</mo>
<mi>k</mi>
<mo>-</mo>
<mn>1</mn>
</mrow>
</msub>
<mo>-</mo>
<msub>
<mi>K</mi>
<mi>k</mi>
</msub>
<msub>
<mi>P</mi>
<mrow>
<msub>
<mi>y</mi>
<mi>k</mi>
</msub>
<msub>
<mi>y</mi>
<mi>k</mi>
</msub>
</mrow>
</msub>
<msubsup>
<mi>K</mi>
<mi>k</mi>
<mi>T</mi>
</msubsup>
</mrow>
In formula:λ=α2(L-
κ)-L, i=1,2 ..., 2L, α are normal number, and β represents the distributed intelligence of sample point, and κ is the parameter that weight is distributed, and L is
Stochastic variable X dimension,The weight coefficient of average and variance statistic characteristic corresponding to respectively i-th sample point;
X0For the initial value of system stochastic variable, i.e. step 2) obtained by result, P0For covariance initial value,For the k-1 moment
Sample point set, Yi,k|k-1To convert point set,For a step look-ahead value of stochastic variable,Carried for a step of observed quantity
Preceding predicted value, YkMeasured for the systematic perspective at k moment,For a step look-ahead covariance matrix,WithFor covariance
Matrix, PkFor the covariance matrix value at k moment, KkFor the filtering gain value at k moment,Stochastic variable for the k moment is estimated
Evaluation, i.e., required node coordinate value.