DE10327675B4 - Method for determining the location xo, the intensity qo and the start of action to the emission of an emission source Eq - Google Patents

Abstract

Method for determining the location x ₀ , the intensity q ₀ and the start of action t _{0 of} the emission of an emission source E _Q by measuring the concentration C _{i of} the emitted substance at a plurality of spatially distributed measuring points i and computer-aided processing of the measured values C _i ,
consisting of the process steps:
Recording the concentration C _i (t) at the individual sensors i and deriving the concentration increase, the concentration constant or the concentration drop at the sensors / measuring points i,
Measuring the flow velocity v of the emission by amount and direction,
either
in the case of an increase in concentration at the sensors i shortly after a start of action:
Estimating the start of action t ₀ with an output error-based estimation on the basis of the measured value C _{i of} the / the highest-measuring sensor / measuring point i,
Estimating a scalable distance emission source sensor r _i for each sensor i based on output error based on the respective temporal concentration curve C _i (t);
or
at approximately stationary concentration at the sensors i: calculation of a scalable distance r _i emission source sensor for each sensor i ...

Description

The invention relates to a computer-aided method for determining the location x ₀ , the intensity q ₀ and the start of action t _{0 of} the emission of an emission source E _Q by measuring the concentration C _{i of} the emitted substance at a plurality of spatially distributed measuring points i and computer-aided processing of the measured values C _i .

• – Aufzeichnen der Konzentration an den einzelnen Sensoren A ... F, Messen der Strömungsgeschwindigkeit der die Emission tragenden Strömung (Wind) nach Betrag und Richtung, woraus eine Massenflussrichtungsverteilung an jedem Sensorort A ... F ermittelt wird, und
• – der wahrscheinlichste Ort der Emissionsquelle der Emission anhand aller Massenflussrichtungsverteilungen (an den Orten A ... F) mittels numerischer Verfahren berechnet wird und
• – das Ergebnis auf einem Datensichtgerät (computer display system) mit Angabe der Wahrscheinlichkeit des Ortes der Emissionsquelle zur Weiterverwendung ausgegeben wird.

In the US 5,604,299 A method for determining the location P (x, y) and also the intensity of the emission of an emission source is described by measuring the concentration of the emitted substance at a plurality of spatially distributed measuring points A ... F and computer-aided processing of the measured values with the method steps:

• - recording the concentration at the individual sensors A ... F, measuring the flow velocity of the emission-carrying flow (wind) by magnitude and direction, from which a mass flow direction distribution at each sensor location A ... F is determined, and
• - the most probable location of the emission source of the emission is calculated by means of numerical methods on the basis of all mass flow direction distributions (at the locations A ... F), and
• The result is output on a computer display system indicating the likelihood of the location of the emission source for further use.

In the US 5,185,529 A method for determining the location x of the emission of a (radioactive) emission source is described, by means of measuring the intensity of the emission at a plurality of spatially distributed measuring points (detectors) and computer-aided processing of the measured values with recording of the measured values by sensors, generating functions from measured values , wherein the type of the respective function depends on the order of the sensors with respect to the size of the respective measured value, and calculating the location x of the emission source by means of numerical methods.

Mehmet E. Alpay and Molly H in the article "Model based Solution Techniques for the Source Localization Problem "three methods:" Intelligent Brute Force Method "," Discretization Method "and" Dual System Approach. "The" Intelligent Brute Force method "classified between known a priori source locations based on reference patterns. The "Discretization method "generated on the basis of an analytic mathematical model, diffusion advection equation, a rough approximation in the form of a discrete state space model by time and place Discretization. The assumption is made that both the sources as well as the sensors are located on the grid points. This simplified model is used to determine the source location. When "dual system approach "can become the emission source is located anywhere in the room. On the basis of steady-state end values the solution the propagation equation, diffusion advection equation, becomes the source location determined.

"The intelligent brute force method " classify only between a priori known source locations, but do not find any source location. In addition, it can be with it unknown source intensities do not consider. Due to the gross discretization in the "Discretization method" and the assumption that both the sources and the sensors are on the grid points of the discretization grid is just a very rough localization possible. The Condition of inpatient solutions the propagation equation (diffusion advection equation) in the "dual system approach" is in many cases not Fulfills, e.g. pulsed Source intensity over the Time. There the procedure is not applicable.

In any point of the monitored Area (chemical storage or process plant) can at any one time an emission source with unknown intensity to start working.

from that gave the object of the invention is based, namely a new / improved computerized To provide a method by which the place, the intensity and the Inception of the emission by spatially distributed measurement of the concentration of the emitted substance can be determined at several measuring points.

The The object is achieved by the method steps indicated in claim 1 solved.

First, the concentration C _i (t) is recorded at the individual sensors i and the increase in concentration, the concentration constant or the concentration drop at the sensors / measuring points i are detected.

The flow rate v the emission by amount and direction is measured.

There are two ways:
either at an increase in concentration at the sensors i shortly after a start of action:
the start of action t _{0 is} estimated using an output-error-based estimation based on the measured value C _i of the strongest measuring sensor / measuring point i, then a scalable distance of the emission source sensor r _i for each sensor i with output error-based estimation based on the respective temporal concentration curve C _i (t) determined;
or at approximately stationary concentration at the sensors i:
a scalable distance r _i , emission source sensor, for each sensor i based on output error based estimation is calculated from the respective steady state end value of the concentrations C _i .

From this, one or the other way a scalable sensor-source distance r _{i is determined} for each sensor i.

In the further process:
either with pure diffusion, v = 0:
the location x _{0 of} the emission source and the intensity q _{0 of} the emission calculated on the basis of all distances r _i emission source sensor,
or in diffusion and advection, v> 0:
the location x _{0 of} the emission source and the intensity q _{0 of} the emission are calculated on the basis of all distances r _i emission source sensor by means of a numerical method with a defined computing time.

On a data display device, the result is one way or the other in the form of the information:
the location of the emission source x ₀ ,
the intensity q _{0 of} the emission and
the onset of action
spent / displayed for further use.

By This procedure will be solutions of Propagation equation which determines the variables to be determined: place, intensity and start of effect of the emission source, included as a parameter. Based on these solutions the method becomes a new multi-level parameter estimation problem set up and solved. By decomposing the parameter estimation problem, the method finds even with disturbed ones Measurement signals the clear solution. This is a key advantage of the process as it does not numerical methods in solution the output error parameter estimation problem in suboptimal solutions hang can stay. By using efficient calculation methods is the process is online-enabled.

By The method can be any point source of emission with unknown Intensity and unknown beginning of effect in a chemical storage or in a procedural system determined by means of distributed Messanordungen become. These are in contrast to the classification-based Methods and methods based on discretization methods, e.g. Finite difference methods are based, less measuring points / sensors required in the field. In extreme cases suffice for one-dimensional Spread 2 measuring points, for two-dimensional propagation 3 measuring points and for three-dimensional propagation 4 measuring points.

The Method works even if the diffusion coefficient the system is unknown.

to better manageability the procedure is in its course with the two consecutive ones Turnouts are reproduced in the flowchart shown in the drawing.

The method first determines a scalable sensor-source distance r _i for each sensor, which indicates the distance of the sensor i from the source location as a function of the unknown source intensity. In the case of advection, a measurement of the flow direction and velocity v is necessary for this purpose.

In the period shortly after the source starts to operate, the concentrations at the sensors increase, and the scalable sensor-to-source distances can be determined by iteratively solving an output-error-based optimization problem for each sensor / measuring point. For this, an estimate is necessary for the start of action t _{0 of} the source, which is determined in advance on the basis of the measured values of the highest-measuring sensor.

If the concentrations at the individual sensors have reached approximately stationary end values, the scalable sensor-source distances can be calculated in one step without knowledge of the start of action t ₀ .

Finally, the source location x ₀ and the source intensity q _{0 are} determined on the basis of all scalable sensor-source distances r _i . In the case of pure diffusion (no flow) this is possible by means of a quasi-closed solution.

For the advection diffusion case there is a numerical method for determining source location x ₀ and source intensity q ₀ , which requires a defined, maximum computing time.

Trials show the efficiency of the process. In a chemical storage facility, four sensors were set up to determine the source of a forced, trailing leak. There was a weak airflow in the camp, the direction and strength of which had been identified in advance. Within a period of time in which no costly preserving measures had to be taken, the source location x ₀ and source intensity q _{0 was} determined and the leak sealed.

Claims (1)

Method for determining the location x ₀ , the intensity q ₀ and the start of action t _{0 of} the emission of an emission source E _Q by measuring the concentration C _{i of} the emitted substance at a plurality of spatially distributed measuring points i and computer-aided processing of the measured values C _i , consisting of the Method steps: Recording the concentration C _i (t) at the individual sensors i and deriving the concentration increase, the concentration constant or the concentration drop at the sensors / measuring points i, measuring the flow velocity v of the emission by magnitude and direction, either with an increase in concentration at the sensors i shortly after a start of action: estimating the start of action t ₀ with an output error-based estimation based on the measured value C _i of the highest-measuring sensor / measuring point i, estimating a scalable distance emission source sensor r _i for each sensor i with output-error-based estimation based on the respective time concentration curve C _i (t); or at approximately stationary concentration at the sensors i: calculation of a scalable distance r _i emission source sensor for each sensor i with output error-based estimation based on the respective steady-state end value of the concentrations C _i ; from which one or the other way a scalable sensor-source distance r _{i is determined} for each sensor i, and either in pure diffusion, v = 0: the location x _{0 of} the emission source and the intensity q _{0 of} the emission on the basis of all distances r _i emission source sensor is calculated, or in diffusion and advection, v> 0: the location x _{0 of} the emission source and the intensity q _{0 of} the emission is calculated on the basis of all distances r _i emission source sensor by numerical method with a defined computing time, and on a Data display device, the result of one or the other way in the form of information: the location of the emission source x ₀ , the intensity q _{0 of} the emission and the start of effect is spent for further use.