CN102680657B - Wireless sensor-based detecting and positioning method for pollution source close to impervious boundary - Google Patents

Abstract

The invention relates to a wireless sensor-based detecting and positioning method for a pollution source close to the impervious boundary. The method comprises the following steps: n sensor nodes are randomly distributed at areas close to the impervious boundary to be detected and are connected with a terminal node in an RF (Radio Frequency) manner; the terminal node is in wireless connection with a gateway which is connected with a PC through a serial port line; a management software is installed in the PC; the sensors detect whether the pollution source exists or not through a detection module in the management software; the nodes detecting out the pollution source are saved and compared with a steady-state concentration difference value Delta c in an analyzing module at a pollution source diffusion stage and then enter a positioning module 1 or 2, so as to obtain the position coordinates of the pollution source detected by the corresponding nodes; and finally, the position coordinates of the pollution source detected by all the nodes are averaged to serve as the position coordinate of the pollution source. The method provided by the invention has the characteristics of strong operability, high accuracy and low cost, and is tally with the practical pollution discharge situation.

Description

Close impervious boundary pollution source detecting and locating method based on wireless senser

Technical field

The present invention relates near impervious boundary pollution source detecting and locating technical field, specifically a kind of close impervious boundary pollution source detecting and locating method based on wireless senser.

Background technology

In recent years, water environment protection has been subject to various circles of society and has paid close attention to more widely, and in water environment, the critical role of the detecting and locating technology of pollution source in environmental protection highlights.Generally; water pollution is from the bank discharge of the waste water near bank factory, waste residue, and therefore, near the detecting and locating technology of the close impervious boundary of pollution source lakeside pollution source is for finding pollution source; protect and improve environment, ensureing human body safe drinking water important in inhibiting.

At present, the orientation problem of pollution source is mainly for gaseous contamination source, but the diffusion mechanism in Pollutant Source in Aquatic Environment and gaseous contamination source is not quite similar.In gas, the diffusion of pollution source is not subject to boundary constraint.Actual water body is subject to the impact on water-bed and bank, is not unlimited, therefore the diffusion of pollution source is subject to edge effect.Therefore for the method for gas-monitoring and location, be not suitable for the detecting and locating of pollution source of water body.In addition the detecting and locating method of existing pollution source of water body mainly contains remote sensing technology, underwater robot location technology, manual detection location technology, but said method exists a lot of shortcomings, and such as involving great expense, operability is not strong, the cycle is long etc.

Generally speaking, there is many drawbacks in current detecting and locating technology, lacks feasibility, and finding a kind of littoral detecting and locating method tallying with the actual situation is problem demanding prompt solution.

Summary of the invention

The present invention is intended to overcome prior art defect, and object is to provide a kind of realistic river blowdown situation, the close impervious boundary pollution source detecting and locating method based on wireless senser that workable, degree of accuracy is high and with low cost.

In order to realize foregoing invention object, the technical solution used in the present invention is following steps:

Step 1, in close impervious boundary to be measured, dispose wireless sensor node

(in the lake water within the scope of bank or dykes and dams 1m) stochastic distribution n sensor node in close impervious boundary to be measured, sensor node coordinate is (x _i, y _i) (i=1,2,3....n>=3), sensor node is connected with terminal node in the mode of radio frequency, terminal node and gateway wireless connections, and gateway is connected with PC by Serial Port Line; Software management system is housed in PC, and software management system comprises pollution source detecting module, pollution source diffusion phase analysis module, the first locating module and the second locating module.

The detection of step 2, close impervious boundary pollution entering the water

Set: water depth is f, and water body initial ion concentration is Cc, near impervious boundary, have one section of blow-off pipe that stretches into middle of a lake length l the unknown; Known: the rate of release of this blow-off pipe is Q, the concentration of pollution source is C ₀; Take impervious boundary as Y-axis, and it is X-axis that the blow-off pipe of take stretches into direction in lake, and the intersection point of blow-off pipe and Y-axis of take is set up rectangular coordinate system M as initial point.

Sensor node (x _i, y _i) to detect water body ion concentration be C _i(t), if C _i(t)-Cc>=10mg/l, sensor node (x _i, y _i) existence near impervious boundary pollution source detected.

The steady state (SS) judgement of step 3, pollution source diffusion

Sensor node (x _i, y _i) existence of pollution source at t, constantly being detected, water body ion concentration is C _i(t), sensor node (x _i, y _i) when time interval Δ t, to record ion concentration be C _i(t+ Δ t).

Suppose that be isotropic near impervious boundary pollution source when spreading, the coefficient of diffusion of pollution source on x axle and y axle is D _x=D _y=D, δ _cfor pollution source spread the concentration difference threshold values that reaches steady state (SS),

${\mathrm{\δ}}_c=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}(C(x_i,y_i,t_a+\mathrm{\ΔT})-C(x_i,y_i,t_a))/n---\left(1\right)$

In formula (1):

T _afor pollution source start to diffuse to time of steady state (SS), t _aconventionally get 100 days;

Δ T is the time interval that pollution source diffuse to detect ion concentration after steady state (SS), and Δ T gets 1 day conventionally.

$C(x_i,y_i,t_a)=\frac{{\mathrm{QC}}_0}{2\sqrt{\mathrm{\πD}}f}[\frac{1}{r_i}\mathrm{erfc}\left(\frac{r_i}{2\sqrt{{\mathrm{Dt}}_a}}\right)+\frac{1}{\stackrel{\‾}{r_i}}\mathrm{erfc}\left(\frac{\stackrel{\‾}{r_i}}{2\sqrt{{\mathrm{Dt}}_a}}\right)]---\left(2\right)$

$C(x_i,y_i,t_a+\mathrm{\ΔT})=\frac{{\mathrm{QC}}_0}{2\sqrt{\mathrm{\πD}}f}[\frac{1}{r_i}\mathrm{erfc}\left(\frac{r_i}{2\sqrt{D(t_a+\mathrm{\ΔT})}}\right)+\frac{1}{\stackrel{\‾}{r_i}}\mathrm{erfc}\left(\frac{\stackrel{\‾}{r_i}}{2\sqrt{D(t_a+\mathrm{\ΔT})}}\right)]---\left(3\right)$

In formula (2) and formula (3):

erfc(x)＝1-erf(x) （4）

$\stackrel{\‾}{r_i}=\sqrt{{(x_i-L)}^2+{y_i}^2}---\left(5\right)$

$r_i=\sqrt{{(x_i-L)}^2+{y_i}^2}---\left(6\right)$

In formula (5) and formula (6):

10m≤L≤40m。

If at time interval Δ t inner sensor node (x _i, y _i) the poor δ of being greater than of ion concentration that records _c, pollution source diffusion does not reach steady state (SS); If at time interval Δ t inner sensor node (x _i, y _i) the poor δ of being less than or equal to of ion concentration that records _c, pollution source diffusion reaches steady state (SS).

The location of step 4, close impervious boundary pollution source

(1) when pollution source diffusion does not reach steady state (SS), i.e. C _i(t+ Δ t)-C _i(t) > δ _ctime, by sensor node (x _i, y _i) length l of the blow-off pipe of constantly locating at t is the solution of formula (7):

$\left\{\begin{array}{c}{C}_i(t+\mathrm{\Δt})-C_i\left(t\right)=\frac{{\mathrm{QC}}_0}{2f\sqrt{\mathrm{\πD}}}(\frac{1}{2\sqrt{\mathrm{Dt}}}-\frac{1}{2\sqrt{D(t+\mathrm{\Δt})}})\\ C_i\left(t\right)=\frac{{\mathrm{QC}}_0}{2f\sqrt{\mathrm{\πD}}}(\frac{1}{r_i}-\frac{1}{2\sqrt{\mathrm{Dt}}})\end{array}\right.---\left(7\right)$

In formula (7):

$r_i=\sqrt{{(x_i-l)}^2+{y_i}^2}.$

(2) when pollution source diffusion reaches steady state (SS), i.e. C _i(t+ Δ t)-C _i(t)≤δ _ctime, by sensor node (x _i, y _i) length l of the blow-off pipe of constantly locating at t is the solution of formula (8):

$\left\{\begin{array}{c}{C}_i(t+\mathrm{\Δt})-C_i\left(t\right)=\frac{{\mathrm{QC}}_0}{2f\sqrt{\mathrm{\πD}}}(\frac{1}{\sqrt{\mathrm{Dt}}}-\frac{1}{\sqrt{D(t+\mathrm{\Δt})}})\\ C_i\left(t\right)=\frac{{\mathrm{QC}}_0}{2f\sqrt{\mathrm{\πD}}}(\frac{1}{r_i}+\frac{1}{\stackrel{\‾}{r_i}}-\frac{1}{\sqrt{\mathrm{Dt}}})\end{array}\right.---\left(8\right)$

In formula (8):

$\stackrel{\‾}{r_i}=\sqrt{{(x_i+l)}^2+{y_i}^2};$

$r_i=\sqrt{{(x_i-l)}^2+{y_i}^2}.$

(3) in actual measurement, with n the sensor node (x near impervious boundary stochastic distribution _i, y _i) in detect k the node (x that pollution source exist _j, y _j) (j=1,2,3....k, 3≤k≤n) position, and works as C _j(t+ Δ t)-C _j(t)>=δ _ctime, according to formula (7), solve l _jvalue; Work as C _j(t+ Δ t)-C _j(t) < δ _ctime, according to formula (8), solve l _jvalue, the l that t is located constantly _javerage length as blow-off pipe is the position coordinates of pollution source is

The main flow of described software management system is:

S-101, initialization;

S-102, reception data;

Do S-103, data finish receiving?

If S-104 has accepted, carry out S-105; If do not accepted, carry out S-102;

S-105, call pollution source detecting module;

S-106, the existence of pollution source detected?

S-107, be to carry out S-108; No, carry out S-102;

The related data that S-108, preservation detect the node of pollution source existence arrives database;

In S-109, database, whether the data recording of same node is greater than 2 times

S-110, be to carry out S-113; No, carry out S-111;

Does the time interval of the same node of first record equal Δ t in S-111, current time and database?

S-112, be to carry out S-102; No, carry out S-111;

S-113, call pollution source diffusion phase analysis module;

S-114、C _i(t+Δt)-C _i(t)＞δ _c？

S-115, be, data are saved to not steady state (SS) data group, call the first locating module; No, data are saved to steady state (SS) data group, call the second locating module;

S-116, the value in database is averaged, this mean value, as last positioning result, is preserved;

S-117, demonstration pollution source position coordinates

Described detecting module main flow is:

S-201, device initialize;

S-202, accept new data message?

S-203, be to carry out S-204; No, carry out S-202;

The data that S-204, extraction PC are accepted;

S-205, calculating also judge C _i(t)-Cc>=10mg/l?

S-206, be to preserve the position (x of this node _i, y _i) and C _i(t) to database; No, carry out S-202;

S-207, end.

Described analysis module main flow is:

S-301, device initialize;

The data message of same node in S-302, extraction database;

S-303, judgement C _i(t+ Δ t)-C _i(t) > δ _c?

S-304, be, data are saved to not steady state (SS) data group, call the first locating module; No, data are saved to steady state (SS) data group, call the second locating module.

The first described locating module main flow is:

S-401, device initialize;

S-402, extract the data message of same node in steady state (SS) data group not;

S-403, call the value that formula (7) is calculated l;

S-404, the value of positioning result l is saved in to database;

S-405, end.

The second described locating module main flow is:

S-501, device initialize;

The data message of same node in S-502, extraction steady state (SS) data group;

S-503, call the value that formula (8) is calculated l;

S-504, the value of positioning result l is saved in to database;

S-505, end.

Owing to adopting technique scheme, the water pollution of the realistic lake water of the present invention, from the factory's Drainage feature near bank or dykes and dams (being impervious boundary), therefore has actual using value.In actual mechanical process, only need to be by n sensor node stochastic distribution in the scope of offshore limit 1m, sensor node is connected with 1 terminal node with RF-wise, terminal node and 1 gateway wireless connections, gateway is connected with PC by Serial Port Line; In PC, according to setting up one dimension Time Continuous Stochastic Diffusion Model near the diffusion phase at pollution source place, impervious boundary, can determine pollution source position coordinates, therefore easy to operate, simple.

In addition, because the present invention adopts wireless senser, node is densely distributed, has increased the monitored area covering, and is easy to perception monitoring objective, with low cost; Sensor node distributes and is not subject to the restriction in geographic position, in some special applications, when detecting target and be motion state or the mankind and cannot directly monitor, the node of sensor can complete monitoring task well, overcome conventional art operability not strong, the shortcoming involve great expense, the cycle being long.Especially the localization method adopting is used Newton iteration method, is optimized, therefore possess very high precision.

Therefore, the present invention have workable, degree of accuracy is high, the feature of with low cost and realistic blowdown situation.

Accompanying drawing explanation

Fig. 1 is the main flow chart of management software in PC;

Fig. 2 is the main flow chart of detecting module in Fig. 1;

Fig. 3 is the main flow chart of phase analysis module in Fig. 1;

Fig. 4 is the main flow chart of locating module 1 in Fig. 1;

Fig. 5 is the main flow chart of locating module 2 in Fig. 1.

Embodiment

Below in conjunction with the drawings and specific embodiments, the present invention will be further described, not the restriction to its protection domain.

Embodiment 1

A close impervious boundary pollution source detecting and locating method based on wireless senser, the steps include:

Step 1, in close impervious boundary to be measured, dispose wireless sensor node

(in the lake water within the scope of bank or dykes and dams 1m) 10 sensor nodes of stochastic distribution in close impervious boundary to be measured, sensor node coordinate is (x _i, y _i) (i=1,2,3....10), sensor node (x _i, y _i) (i=1,2,3....10) mode with radio frequency is connected with terminal node, terminal node and gateway wireless connections, gateway is connected with PC by Serial Port Line; Software management system is housed in PC, and software management system comprises pollution source detecting module, pollution source diffusion phase analysis module, the first locating module and the second locating module.

The detection of step 2, close impervious boundary pollution entering the water

Set: water depth is f=5m, and water body initial ion concentration is Cc=0.1mg/L, near impervious boundary, have one section of blow-off pipe that stretches into middle of a lake length l the unknown; Known: the rate of release of these pollution source is Q=1.5m ³/ L, the concentration of pollution source is C ₀=5000mg/L; Take impervious boundary as Y-axis, and it is X-axis that the blow-off pipe of take stretches into direction in lake, and the intersection point of blow-off pipe and Y-axis of take is set up rectangular coordinate system M as initial point.

10 sensor node (x _i, y _i) (i=1,2, there are 5 sensor node (x in 3....10) _i, y _i) (i=1,3,6,8,10) to detect water body ion concentration be C _i(t) the water body ion concentration C, detecting _i(t) as shown in table 1.1, i.e. C _i(t)-0.1mg/l>=10mg/l, sensor node (x _i, y _i) (i=1,3,6,8,10) detect the existence near impervious boundary pollution source.

Table 1.1 sensor node (x _i, y _i) (i=1,3,6,8,10) detect water body ion concentration constantly at t

The steady state (SS) judgement of step 3, pollution source diffusion

As described in step 2, sensor node (x _i, y _i) (i=1,3,6,8,10) detect the existence of pollution source constantly at t, water body ion concentration is C _i(t), sensor node (x _i, y _i) (i=1,3,6,8,10) when time interval Δ t=540s, to record water body ion concentration be C _i(t+540) the water body ion concentration C, detecting _i(t+540) as shown in table 1.2:

Table 1.2 sensor node (x _i, y _i) (i=1,3,6,8,10) record water body ion concentration when time interval Δ t=540s

Suppose that be isotropic near impervious boundary pollution source when spreading, the coefficient of diffusion of pollution source on x axle and y axle is D _x=D _y=0.1m ²/ s, δ _cfor pollution source diffusion reaches stable concentration difference threshold values;

${\mathrm{\&delta;}}_c=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}(C(x_i,y_i,t_a+\mathrm{\&Delta;T})-C(x_i,y_i,t_a))/n---\left(1\right)$

In formula (1)

T _afor pollution source start to diffuse to time of steady state (SS), t _aconventionally get 100 days;

Δ T is the time interval that pollution source diffuse to detect ion concentration after steady state (SS), and Δ T gets 1 day conventionally;

$C(x_1,y_1,t_a)=\frac{{\mathrm{QC}}_0}{2\sqrt{\mathrm{\&pi;D}}f}[\frac{1}{r_1}\mathrm{erfc}\left(\frac{r_1}{2\sqrt{{\mathrm{Dt}}_a}}\right)+\frac{1}{\stackrel{\&OverBar;}{r_1}}\mathrm{erfc}\left(\frac{\stackrel{\&OverBar;}{r_1}}{2\sqrt{{\mathrm{Dt}}_a}}\right)]=248.8502\mathrm{mg}/l---\left(2\right)$

$C(x_1,y_1,t_a+\mathrm{\&Delta;T})=\frac{{\mathrm{QC}}_0}{2\sqrt{\mathrm{\&pi;D}}f}[\frac{1}{r_1}\mathrm{erfc}\left(\frac{r_1}{2\sqrt{D(t_a+\mathrm{\&Delta;T})}}\right)+\frac{1}{\stackrel{\&OverBar;}{r_1}}\mathrm{erfc}\left(\frac{\stackrel{\&OverBar;}{r_1}}{2\sqrt{D(t_a+\mathrm{\&Delta;T})}}\right)]=248.8903\mathrm{mg}/l---\left(3\right)$

δ _c1＝C(x ₁,y ₁,t _a+ΔT)-C(x ₁,y ₁,t _a)＝0.0401m

In formula (2) and formula (3):

erfc(x)＝1-erf(x) （4）

$\stackrel{\&OverBar;}{r_1}=\sqrt{{(x_1-L)}^2+{y_1}^2}=10.0209m---\left(5\right)$

$r_1=\sqrt{{(x_1-L)}^2+{y_1}^2}=9.9624m---\left(6\right)$

In formula (5) and formula (6):

10m?≤L≤40m

In the present embodiment:

L＝10m；

In like manner can obtain δ _ci(i=1,2,3....10), δ _cias shown in table 1.3:

Table 1.3 δ _ci(i=1,2, value 3....10)

By table 1.3, can be obtained:

${\mathrm{\&delta;}}_c=\underset{i=1}{\overset{10}{\mathrm{\&Sigma;}}}(C(x_i,y_i,t_a+\mathrm{\&Delta;T})-C(x_i,y_i,t_a))/10=\underset{i=1}{\overset{10}{\mathrm{\&Sigma;}}}{\mathrm{\&delta;}}_{c_i}=0.0401\mathrm{mg}/l$

When time interval Δ t=540s, sensor node (x _i, y _i) (i=1,3,6,8,10) poor C of ion concentration of recording _i(t+540)-C _i(t) as shown in table 1.4:

Table 1.4 sensor node (x _i, y _i) (i=1,3,6,8,10) ion concentration of recording is poor

From table 1.4, can find out, at time interval Δ t=540s inner sensor node (x _i, y _i) (i=1,3,6,8,10) poor δ of being greater than of ion concentration of recording _c=00401mg/l, pollution source diffusion does not reach steady state (SS).

The location of step 4, close impervious boundary pollution source

In the present embodiment, get 10 sensor node (x near impervious boundary stochastic distribution _i, y _i) (i=1,2, detect 5 node (x that pollution source exist in 3....10) _i, y _i) (i=1,3,6,8,10) position, other 5 node (x _i, y _i) (i=2,4,5,7,9) due to C _i(t)-01mg/l < 10mg/l does not detect pollution source, therefore do not participate in location.

Pollution source diffusion does not reach steady state (SS), works as C ₁(t+540)-C ₁(t) during > 00401mg/l, by sensor node (x ₁, y ₁) length l of the blow-off pipe of constantly locating at t is the solution of formula (7):

$\left\{\begin{array}{c}106.263-25.523=\frac{1.5*5000}{2*5\sqrt{\mathrm{\&pi;}*0.1}}(\frac{1}{2\sqrt{0.1*t}}-\frac{1}{2\sqrt{0.1*(t+540)}})\\ 25.523=\frac{1.5*5000}{2*5\sqrt{\mathrm{\&pi;}*0.1}}(\frac{1}{r1}-\frac{1}{2\sqrt{0.1*t}})\end{array}\right.---\left(7\right)$

In formula (7):

$r_1=\sqrt{{(x_1-l)}^2+{y_1}^2}=9.2195\mathrm{mg}/l;$

Solve: l ₁=7.9356m.

In like manner can obtain: l ₂=7.4059m;

l ₃＝7.522m；

l ₄＝7.2618m；

l ₅＝7.4902m。

The l that t is located constantly _javerage length as blow-off pipe:

$\stackrel{\&OverBar;}{l}=\underset{j=1}{\overset{5}{\mathrm{\&Sigma;}}}{l}_j/5=7.5231m;$

The position coordinates of pollution source is (7.5231,0).

Described in the present embodiment, the main flow of software management system is:

S-101, initialization;

S-102, reception data;

Do S-103, data finish receiving?

If S-104 has accepted, carry out S-105; If do not accepted, carry out S-102;

S-105, call pollution source detecting module;

S-106, the existence of pollution source detected?

S-107, be to carry out S-108; No, carry out S-102;

The related data that S-108, preservation detect the node of pollution source existence arrives database;

In S-109, database, whether the data recording of same node is greater than 2 times

S-110, be to carry out S-113; No, carry out S-111;

Does the time interval of the same node of first record equal Δ t in S-111, current time and database?

S-112, be to carry out S-102; No, carry out S-111;

S-113, call pollution source diffusion phase analysis module;

S-114、C _i(t+Δt)-C _i(t)＞δ _c？

S-115, be, data are saved to not steady state (SS) data group, call the first locating module; No, data are saved to steady state (SS) data group, call the second locating module;

S-116, the value in database is averaged, this mean value, as last positioning result, is preserved;

S-117, demonstration pollution source position coordinates

Detecting module main flow described in the present embodiment is:

S-201, device initialize;

S-202, accept new data message?

S-203, be to carry out S-204; No, carry out S-202;

The data that S-204, extraction PC are accepted;

S-205, calculating also judge C _i(t)-Cc>=10mg/l?

S-206, be to preserve the position (x of this node _i, y _i) and C _i(t) to database; No, carry out S-202;

S-207, end.

Analysis module main flow described in the present embodiment is:

S-301, device initialize;

The data message of same node in S-302, extraction database;

S-303, judgement C _i(t+ Δ t)-C _i(t) > δ _c?

S-304, be, data are saved to not steady state (SS) data group, call the first locating module; No, data are saved to steady state (SS) data group, call the second locating module;

The first locating module main flow described in the present embodiment is:

S-401, device initialize;

S-402, extract the data message of same node in steady state (SS) data group not;

S-403, call the value that formula (7) is calculated l;

S-404, the value of positioning result l is saved in to database;

S-405, end.

The second locating module main flow described in the present embodiment is:

S-501, device initialize;

The data message of same node in S-502, extraction steady state (SS) data group;

S-503, call the value that formula (8) is calculated l;

S-504, the value of positioning result l is saved in to database;

S-505, end.

Embodiment 2

A close impervious boundary pollution source detecting and locating method based on wireless senser, the steps include:

Wireless sensor node is disposed in step 1, close impervious boundary

With embodiment 1.

The detection of step 2, close impervious boundary pollution entering the water

Except following technical parameter, all the other are with embodiment 1.

10 sensor node (x _i, y _i) (i=1,2, there are 5 sensor node (x in 3....10) _i, y _i) (i=1,5,6,7,10) to detect water body ion concentration be C _i(t) the water body ion concentration C, detecting _i(t) as shown in table 2.1, i.e. C _i(t)-0.1mg/l>=10mg/l, sensor node (x _i, y _i) (i=1,2,3....10) existence near impervious boundary pollution source detected.

Table 2.1 sensor node (x _i, y _i) (i=1,5,6,7,10) water body ion concentration of constantly detecting at t

The steady state (SS) judgement of step 3, pollution source diffusion

As described in step 2, sensor node (x _i, y _i) (i=1,5,6,7,10) detect the existence of pollution source constantly at t, water body ion concentration is C _i(t), sensor node (x _i, y _i) (i=1,5,6,7,10) when time interval Δ t=3600s, to record water body ion concentration be C _i(t+3600) the water body ion concentration C, detecting _i(t+3600) as shown in table 2.2:

Table 2.2 sensor node (x _i, y _i) (i=1,5,6,7,10) record water body ion concentration when time interval Δ t=3600s

Suppose that be isotropic near impervious boundary pollution source when spreading, the coefficient of diffusion of pollution source on x axle and y axle is D _x=D _y=0.1m ²/ s, δ _cfor pollution source spread the concentration difference threshold values that reaches steady state (SS);

${\mathrm{\&delta;}}_c=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}(C(x_i,y_i,t_a+\mathrm{\&Delta;T})-C(x_i,y_i,t_a))/n---\left(1\right)$

In formula (1)

T _afor pollution source start to diffuse to stable time, t _aconventionally get 100 days;

Δ T is that pollution source diffuse to the time interval of getting ion concentration after stable, and Δ T gets 1 day conventionally;

$C(x_1,y_1,t_a)=\frac{{\mathrm{QC}}_0}{2\sqrt{\mathrm{\&pi;D}}f}[\frac{1}{r_1}\mathrm{erfc}\left(\frac{r_1}{2\sqrt{{\mathrm{Dt}}_a}}\right)+\frac{1}{\stackrel{\&OverBar;}{r_1}}\mathrm{erfc}\left(\frac{\stackrel{\&OverBar;}{r_1}}{2\sqrt{{\mathrm{Dt}}_a}}\right)]=248.8502\mathrm{mg}/l---\left(2\right)$

$C(x_1,y_1,t_a+\mathrm{\&Delta;T})=\frac{{\mathrm{QC}}_0}{2\sqrt{\mathrm{\&pi;D}}f}[\frac{1}{r_1}\mathrm{erfc}\left(\frac{r_1}{2\sqrt{D(t_a+\mathrm{\&Delta;T})}}\right)+\frac{1}{\stackrel{\&OverBar;}{r_1}}\mathrm{erfc}\left(\frac{\stackrel{\&OverBar;}{r_1}}{2\sqrt{D(t_a+\mathrm{\&Delta;T})}}\right)]=248.8903\mathrm{mg}/l---\left(3\right)$

δ _c1＝C(x ₁,y ₁,t _a+ΔT)-C(x ₁,y ₁,t _a)＝00401m

In formula (2) and formula (3):

erfc(x)＝1-erf(x) （4）

$\stackrel{\&OverBar;}{r_1}=\sqrt{{(x_1-L)}^2+{y_1}^2}=10.0209m---\left(5\right)$

$r_1=\sqrt{{(x_1-L)}^2+{y_1}^2}=9.9624m---\left(6\right)$

In formula (5) and formula (6):

In 10m≤L≤40m the present embodiment:

L＝40m；

In like manner can obtain δ _ci(i=1,2,3....10), δ _cias shown in table 2.3:

Table 2.3 δ _ci(i=1,2, value 3....10)

By table 2.3, can be obtained:

${\mathrm{\&delta;}}_c=\underset{i=1}{\overset{10}{\mathrm{\&Sigma;}}}(C(x_i,y_i,t_a+\mathrm{\&Delta;T})-C(x_i,y_i,t_a))/10=\underset{i=1}{\overset{10}{\mathrm{\&Sigma;}}}{\mathrm{\&delta;}}_{c_i}=0.0401\mathrm{mg}/l$

When time interval Δ t=3600s, sensor node (x _i, y _i) (i=1,5,6,7,10) poor C of ion concentration of recording _i(t+3600)-C _i(t) as shown in table 2.4:

Table 2.4 sensor node (x _i, y _i) (i=1,5,6,7,10) ion concentration of recording is poor

From table 2.4, can find out, at time interval Δ t=3600s inner sensor node (x _i, y _i) (i=1,5) poor δ of being greater than of ion concentration of recording _c=0.0401mg/l, pollution source diffusion does not reach steady state (SS); Sensor node (x _i, y _i) (i=6,7,10) poor δ of being less than or equal to of ion concentration of recording _c=0.0401mg/l, pollution source diffusion reaches steady state (SS).

The location of step 4, close impervious boundary pollution source

In the present embodiment, get 10 sensor node (x near impervious boundary stochastic distribution _i, y _i) (i=1,2, detect 5 node (x that pollution source exist in 3....10) _i, y _i) (i=1,5,6,7,10) position, other 5 node (x _i, y _i) (i=2,3,4,8,9) due to C _i(t)-0.1mg/l < 10mg/l does not detect pollution source, therefore do not participate in location.

Pollution source diffusion does not reach steady state (SS), works as C ₁(t+3600)-C ₁(t) during > 0.0401mg/l, by sensor node (x ₁, y ₁) length l of the blow-off pipe of constantly locating at t is the solution of formula (7):

$\left\{\begin{array}{c}188.919-25.523=\frac{1.5*5000}{2*5\sqrt{\mathrm{\&pi;}*0.1}}(\frac{1}{2\sqrt{0.1*t}}-\frac{1}{2\sqrt{0.1*(t+3600)}})\\ 25.523=\frac{1.5*5000}{2*5\sqrt{\mathrm{\&pi;}*0.1}}(\frac{1}{r1}-\frac{1}{2\sqrt{0.1*t}})\end{array}\right.---\left(7\right)$

In formula (7):

$r_1=\sqrt{{(x_1-l)}^2+{y_1}^2}=9.2195\mathrm{mg}/l.$

Solve: l ₁=6.638m

In like manner can obtain: l ₅=5.9294m;

Pollution source diffusion reaches steady state (SS), works as C ₃(t+3600)-C ₃(t)≤during 0.0401mg/l, by sensor node (x ₆, y ₆) length l of the blow-off pipe of constantly locating at t is that formula (8) is separated:

$\left\{\begin{array}{c}{C}_i(t+3600)-C_i\left(t\right)=\frac{1.5*5000}{2*5\sqrt{\mathrm{\&pi;}*0.1}}(\frac{1}{\sqrt{0.1*t}}-\frac{1}{\sqrt{0.1*(t+3600)}})\\ C_i\left(t\right)=\frac{1.5*5000}{2*5\sqrt{\mathrm{\&pi;}*0.1}}(\frac{1}{r_3}+\frac{1}{\stackrel{\&OverBar;}{r_3}}-\frac{1}{\sqrt{0.1*t}})\end{array}\right.---\left(8\right)$

In formula (8):

$\stackrel{\&OverBar;}{r_6}=\sqrt{{(x_6+l)}^2+{y_6}^2}=11.5169\mathrm{mg}/l;$

$r_6=\sqrt{{(x_6-l)}^2+{y_6}^2}=10.0319\mathrm{mg}/l.$

Solve: l ₆=10.0284m;

In like manner can obtain: l ₇=10.0319m;

l ₁₀＝10.0232m。

The l that t is located constantly _javerage length as blow-off pipe:

$\stackrel{\&OverBar;}{l}=\underset{j=1}{\overset{5}{\mathrm{\&Sigma;}}}{l}_j/5=8.5301m.$

The position coordinates of pollution source is (8.5301,0).

The main flow of the software management system of the present embodiment 2 is with embodiment 1.

Embodiment 3

A close impervious boundary pollution source detecting and locating method based on wireless senser, the steps include:

Step 1, deployment wireless sensor node

Except sensor node (x _i, y _i) (i=1,2, be 3....15) beyond 15, all the other are with embodiment 1.

The detection of step 2, close impervious boundary pollution entering the water

Except following technical parameter, all the other are with embodiment 1.

15 sensor node (x _i, y _i) (i=1,2, there are 6 sensor node (x in 3....15) _i, y _i) (i=1,5,6,7,10,13) to detect water body ion concentration be C _i(t) the water body ion concentration C, detecting _i(t) as shown in table 3.1, i.e. C _i(t)-01mg/l>=10mg/l, sensor node (x _i, y _i) (i=1,5,6,7,10,13) detect the existence near impervious boundary pollution source.

Table 3.1 sensor node (x _i, y _i) (i=1,5,6,7,10,13) detect water body ion concentration constantly at t

The steady state (SS) judgement of step 3, pollution source diffusion

As described in step 2, sensor node (x _i, y _i) (i=1,5,6,7,10,13) detect the existence of pollution source constantly at t, water body ion concentration is C _i(t), sensor node (x _i, y _i) (i=1,5,6,7,10,13) when time interval Δ t=3600s, to record water body ion concentration be C _i(t+3600) the water body ion concentration C, detecting _i(t+3600) as shown in table 3.2:

Table 3.2 sensor node (x _i, y _i) (i=1,5,6,7,10,13) record water body ion concentration when time interval Δ t=3600s

Suppose that be isotropic near impervious boundary pollution source when spreading, the coefficient of diffusion of pollution source on x axle and y axle is D _x=D _y=0.1m ²/ s, δ _cfor pollution source spread the concentration difference threshold values that reaches steady state (SS);

${\mathrm{\&delta;}}_c=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}(C(x_i,y_i,t_a+\mathrm{\&Delta;T})-C(x_i,y_i,t_a))/n---\left(1\right)$

In formula (1)

T _afor pollution source start to diffuse to stable time, t _aconventionally get 100 days,

Δ T is that pollution source diffuse to the time interval of getting ion concentration after stable, and Δ T gets 1 day conventionally,

$C(x_1,y_1,t_a)=\frac{{\mathrm{QC}}_0}{2\sqrt{\mathrm{\&pi;D}}f}[\frac{1}{r_1}\mathrm{erfc}\left(\frac{r_1}{2\sqrt{{\mathrm{Dt}}_a}}\right)+\frac{1}{\stackrel{\&OverBar;}{r_1}}\mathrm{erfc}\left(\frac{\stackrel{\&OverBar;}{r_1}}{2\sqrt{{\mathrm{Dt}}_a}}\right)]=236.1102\mathrm{mg}/l---\left(2\right)$

$C(x_1,y_1,t_a+\mathrm{\&Delta;T})=\frac{{\mathrm{QC}}_0}{2\sqrt{\mathrm{\&pi;D}}f}[\frac{1}{r_1}\mathrm{erfc}\left(\frac{r_1}{2\sqrt{D(t_a+\mathrm{\&Delta;T})}}\right)+\frac{1}{\stackrel{\&OverBar;}{r_1}}\mathrm{erfc}\left(\frac{\stackrel{\&OverBar;}{r_1}}{2\sqrt{D(t_a+\mathrm{\&Delta;T})}}\right)]=236.1503\mathrm{mg}/l---\left(3\right)$

δ _c1＝C(x ₁,y ₁,t _a+ΔT)-C(x ₁,y ₁,t _a)＝0.0401m

In formula (2) and formula (3):

erfc(x)＝1-erf(x) （4）

$\stackrel{\&OverBar;}{r_1}=\sqrt{{(x_1-L)}^2+{y_1}^2}=11.1485m---\left(5\right)$

$r_1=\sqrt{{(x_1-L)}^2+{y_1}^2}=10.7838m---\left(6\right)$

In formula (5) and formula (6):

10m≤L≤40m

In the present embodiment:

L＝20m；

In like manner can obtain δ _ci(i=1,2,3....15) as shown in table 3.3:

Table 3.3 δ _ci(i=1,2, value 3....15)

By table 3.3, can be obtained:

${\mathrm{\&delta;}}_c=\underset{i=1}{\overset{15}{\mathrm{\&Sigma;}}}(C(x_i,y_i,t_a+\mathrm{\&Delta;T})-C(x_i,y_i,t_a))/15=\underset{i=1}{\overset{15}{\mathrm{\&Sigma;}}}{\mathrm{\&delta;}}_{c_i}=0.0401\mathrm{mg}/l$

When time interval Δ t=3600s, sensor node (x _i, y _i) (i=1,5,6,7,10,13) poor C of ion concentration of recording _i(t+3600)-C _i(t) as shown in table 3.4:

Table 3.4 sensor node (x _i, y _i) (i=1,5,6,7,10,13) ion concentration of recording is poor

From table 3.4, can find out, at time interval Δ t=3600s inner sensor node (x _i, y _i) (i=1,5,6,7,10,13) poor δ of being less than or equal to of ion concentration of recording _c=0.0401mg/l, pollution source diffusion reaches steady state (SS).

The location of step 4, close impervious boundary pollution source, gets 15 sensor node (x near impervious boundary stochastic distribution in the present embodiment _i, y _i) (i=1,2, detect 6 node (x that pollution source exist in 3....15) _i, y _i) (i=1,5,6,7,10,13) position, other 9 node (x _i, y _i) (i=2,3,4,8,9,11,12,14,15) due to C _i(t)-0.1mg/l < 10mg/l does not detect pollution source, therefore do not participate in location;

Pollution source diffusion reaches steady state (SS), works as C ₁(t+3600)-C ₁(t) during < 0.0401mg/l, by sensor node (x ₁, y ₁) length l of the blow-off pipe of constantly locating at t is the solution of formula (7);

$\left\{\begin{array}{c}236.1503-236.1102=\frac{1.5*5000}{2*5\sqrt{\mathrm{\&pi;}*0.1}}(\frac{1}{\sqrt{0.1*t}}-\frac{1}{\sqrt{0.1*(t+3600)}})\\ 236.1102=\frac{1.5*5000}{2*5\sqrt{\mathrm{\&pi;}*0.1}}(\frac{1}{r_1}+\frac{1}{\stackrel{\&OverBar;}{r_1}}-\frac{1}{\sqrt{0.1*t}})\end{array}\right.---\left(7\right)$

In formula (7):

$\stackrel{\&OverBar;}{r_1}=\sqrt{{(x_1+l)}^2+{y_1}^2}=11.1485\mathrm{mg}/l,$

$r_1=\sqrt{{(x_1-l)}^2+{y_1}^2}=10.7838\mathrm{mg}/l;$

Solve: l ₁=10.0304m.

In like manner can obtain: l ₅=10.025m;

l ₆＝10.0238m；

l ₇＝10.0364m；

l ₁₀＝10.026m；

l ₁₃＝10.0237m。

The l that t is located constantly _javerage length as blow-off pipe:

$\stackrel{\&OverBar;}{l}=\underset{j=1}{\overset{6}{\mathrm{\&Sigma;}}}{l}_j/6=10.0276m;$

The position coordinates of pollution source is (10.0276,0).

The main flow of the software management system of the present embodiment 3 is with embodiment 1.

The water pollution of the realistic lake water of this embodiment, from the factory's Drainage feature near bank or dykes and dams (being impervious boundary), therefore has actual using value.In actual mechanical process, only need to be by n sensor node stochastic distribution in the scope of offshore limit 1m, sensor node is connected with 1 terminal node with RF-wise, terminal node and 1 gateway wireless connections, gateway is connected with PC by Serial Port Line; In PC, according to the diffusion phase at pollution source place, set up one-dimensional random continuously close impervious boundary diffusion time pollution source diffusion model, can determine pollution source position coordinates, therefore easy to operate, simple.

In addition, because this embodiment adopts wireless senser, node is densely distributed, has increased the monitored area covering, and is easy to perception monitoring objective, with low cost; Sensor node distributes and is not subject to the restriction in geographic position, in some special applications, when detecting target and be motion state or the mankind and cannot directly monitor, the node of sensor can well complete monitoring task, overcome conventional art operability not strong, the shortcoming involve great expense, the cycle being long.Especially the localization method adopting is used Newton iteration method, is optimized, therefore possess very high precision.

Therefore, the present invention have workable, degree of accuracy is high, the feature of with low cost and realistic blowdown situation.

Claims (6)

1. the close impervious boundary pollution source detecting and locating method based on wireless senser, is characterized in that carrying out as follows:

Step 1, in close impervious boundary to be measured, dispose wireless sensor node

At a close impervious boundary stochastic distribution n sensor node to be measured, sensor node coordinate is (x _i, y _i) (i=1,2,3....n>=3), sensor node is connected with terminal node in the mode of radio frequency, terminal node and gateway wireless connections, and gateway is connected with PC by Serial Port Line; Software management system is housed in PC, and software management system comprises pollution source detecting module, pollution source diffusion phase analysis module, the first locating module and the second locating module;

The detection of step 2, close impervious boundary pollution entering the water

Set: water depth is f, and water body initial ion concentration is Cc, near impervious boundary, have one section of blow-off pipe that stretches into middle of a lake length l the unknown; Known: the rate of release of this blow-off pipe is Q, the concentration of pollution source is C ₀; Take impervious boundary as Y-axis, and it is X-axis that the blow-off pipe of take stretches into direction in lake, and the intersection point of blow-off pipe and Y-axis of take is set up rectangular coordinate system M as initial point;

Sensor node (x _i, y _i) to detect water body ion concentration be C _i(t), if C _i(t)-Cc>=10mg/l, sensor node (x _i, y _i) existence near impervious boundary pollution source detected;

The steady state (SS) judgement of step 3, pollution source diffusion

Sensor node (x _i, y _i) existence of pollution source at t, constantly being detected, water body ion concentration is C _i(t), sensor node (x _i, y _i) when time interval Δ t, to record ion concentration be C _i(t+ Δ t);

Suppose that be isotropic near impervious boundary pollution source when spreading, the coefficient of diffusion of pollution source on x axle and y axle is D _x=D _y=D, δ _cfor pollution source spread the concentration difference threshold values that reaches steady state (SS),

${\mathrm{\&delta;}}_c=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}(C(x_i,y_i,t_a+\mathrm{\&Delta;T})-C(x_i,y_i,t_a))/n---\left(1\right)$

In formula (1):

T _afor pollution source start to diffuse to time of steady state (SS), t _aconventionally get 100 days,

Δ T is the time interval that pollution source diffuse to detect ion concentration after steady state (SS), and Δ T gets 1 day conventionally,

$C(x_i,y_i,t_a)=\frac{Q{C}_0}{2\sqrt{\mathrm{\&pi;D}}f}[\frac{1}{r_i}\mathrm{erfc}\left(\frac{r_i}{2\sqrt{D{t}_a}}\right)+\frac{1}{\stackrel{\&OverBar;}{r_i}}\mathrm{erfc}\left(\frac{\stackrel{\&OverBar;}{r_i}}{2\sqrt{D{t}_a}}\right)]---\left(2\right)$

$C(x_i,y_i,t_a+\mathrm{\&Delta;T})=\frac{Q{C}_0}{2\sqrt{\mathrm{\&pi;D}}f}[\frac{1}{r_i}\mathrm{erfc}\left(\frac{r_i}{2\sqrt{D(t_a+\mathrm{\&Delta;T})}}\right)+\frac{1}{\stackrel{\&OverBar;}{r_i}}\mathrm{erfc}\left(\frac{\stackrel{\&OverBar;}{r_i}}{2\sqrt{D(t_a+\mathrm{\&Delta;T})}}\right)]---\left(3\right)$

In formula (2) and formula (3):

erfc(x)＝1-erf(x) (4)

$\stackrel{\&OverBar;}{r_i}=\sqrt{{(x_i+l)}^2+{y_i}^2}---\left(5\right)$

$r_i=\sqrt{{(x_i-l)}^2+{y_i}^2}---\left(6\right)$

In formula (5) and formula (6):

10m≤l≤40m；

If at time interval Δ t inner sensor node (x _i, y _i) the poor δ of being greater than of ion concentration that records _c, pollution source diffusion does not reach steady state (SS); If at time interval Δ t inner sensor node (x _i, y _i) the poor δ of being less than or equal to of ion concentration that records _c, pollution source diffusion reaches steady state (SS);

The location of step 4, close impervious boundary pollution source

(1) when pollution source diffusion does not reach steady state (SS), i.e. C _i(t+ Δ t)-C _i(t) > δ _ctime, by sensor node (x _i, y _i) length l of the blow-off pipe of constantly locating at t is the solution of formula (7):

$\left\{\begin{array}{c}{C}_i(t+\mathrm{\&Delta;t})-C_i\left(t\right)=\frac{Q{C}_0}{2f\sqrt{\mathrm{\&pi;D}}}(\frac{1}{2\sqrt{\mathrm{Dt}}}-\frac{1}{2\sqrt{D(t+\mathrm{\&Delta;t})}})\\ C_i\left(t\right)=\frac{Q{C}_0}{2f\sqrt{\mathrm{\&pi;D}}}(\frac{1}{r_i}-\frac{1}{2\sqrt{\mathrm{Dt}}})\end{array}\right.---\left(7\right)$

In formula (7):

$r_i=\sqrt{{(x_i-l)}^2+{y_i}^2};$

(2) when pollution source diffusion reaches steady state (SS), i.e. C _i(t+ Δ t)-C _i(t)≤δ _ctime, by sensor node (x _i, y _i) length l of the blow-off pipe of constantly locating at t is the solution of formula (8):

$\left\{\begin{array}{c}{C}_i(t+\mathrm{\&Delta;t})-C_i\left(t\right)=\frac{Q{C}_0}{2f\sqrt{\mathrm{\&pi;D}}}(\frac{1}{2\sqrt{\mathrm{Dt}}}-\frac{1}{2\sqrt{D(t+\mathrm{\&Delta;t})}})\\ C_i\left(t\right)=\frac{Q{C}_0}{2f\sqrt{\mathrm{\&pi;D}}}(\frac{1}{r_i}+\frac{1}{\stackrel{\&OverBar;}{r_i}}-\frac{1}{2\sqrt{\mathrm{Dt}}})\end{array}\right.---\left(8\right)$

In formula (8):

$\stackrel{\&OverBar;}{r_i}=\sqrt{{(x_i+l)}^2+{y_i}^2},$

$r_i=\sqrt{{(x_i-l)}^2+{y_i}^2};$

(3) in actual measurement, with n the sensor node (x near impervious boundary stochastic distribution _i, y _i) in detect k the node (x that pollution source exist _j, y _j) (j=1,2,3....k, 3≤k≤n) position, and works as C _j(t+ Δ t)-C _j(t) > δ _ctime, according to formula (7), solve l _jvalue; Work as C _j(t+ Δ t)-C _j(t)≤δ _ctime, according to formula (8), solve l _jvalue, the l that t is located constantly _javerage length as blow-off pipe is the position coordinates of pollution source is

2. the close impervious boundary pollution source detecting and locating method based on wireless senser according to claim 1, is characterized in that the main flow of described software management system is:

S-101, initialization;

S-102, reception data;

Do S-103, data finish receiving?

If S-104 has accepted, carry out S-105; If do not accepted, carry out S-102;

S-105, call pollution source detecting module;

S-106, the existence of pollution source detected?

S-107, be to carry out S-108; No, carry out S-102;

The related data that S-108, preservation detect the node of pollution source existence arrives database;

Does is the data recording of same node greater than 2 times in S-109, database?

S-110, be to carry out S-113; No, carry out S-111;

Does the time interval of the same node of first record equal Δ t in S-111, current time and database?

S-112, be to carry out S-102; No, carry out S-111;

S-113, call pollution source diffusion phase analysis module;

S-114、C _i(t+Δt)-C _i(t)＞δ _c？

S-115, be, data are saved to not steady state (SS) data group, call the first locating module; No, data are saved to steady state (SS) data group, call the second locating module;

S-116, the value in database is averaged, this mean value, as last positioning result, is preserved;

S-117, demonstration pollution source position coordinates

3. the close impervious boundary pollution source detecting and locating method based on wireless senser according to claim 2, is characterized in that described detecting module main flow is:

S-201, device initialize;

S-202, accept new data message?

S-203, be to carry out S-204; No, carry out S-202;

The data that S-204, extraction PC are accepted;

S-205, calculating also judge C _i(t)-Cc>=10mg/l?

S-206, be to preserve the position (x of this node _i, y _i) and C _i(t) to database; No, carry out S-202;

S-207, end.

4. the close impervious boundary pollution source detecting and locating method based on wireless senser according to claim 2, is characterized in that described analysis module main flow is:

S-301, device initialize;

The data message of same node in S-302, extraction database;

S-303, judgement C _i(t+ Δ t)-C _i(t) > δ _c?

S-304, be, data are saved to not steady state (SS) data group, call the first locating module; No, data are saved to steady state (SS) data group, call the second locating module.

5. the close impervious boundary pollution source detecting and locating method based on wireless senser according to claim 2, is characterized in that the first described locating module main flow is:

S-401, device initialize;

S-402, extract the data message of same node in steady state (SS) data group not;

S-403, call the value that formula (7) is calculated l;

S-404, the value of positioning result l is saved in to database;

S-405, end.

6. the close impervious boundary pollution source detecting and locating method based on wireless senser according to claim 2, is characterized in that the second described locating module main flow is:

S-501, device initialize;

The data message of same node in S-502, extraction steady state (SS) data group;

S-503, call the value that formula (8) is calculated l;

S-504, the value of positioning result l is saved in to database;

S-505, end.