1. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Fachhochschule Lausitz, Senftenberg Systems Engineering MASTER THESIS SAMPATH KUMAR UPPU (Matriculation Nr.212835) Supervisors: Prof. Dr.-Ing. E. Stein, FH Lausitz, Senftenberg Dr. H. Grüger Fraunhofer Institute for Photonic Microsystems, Dresden Prof. Dr.-Ing. B. K. Glück FH Lausitz, Senftenberg

2. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Contents  Introduction  Problem definition  Importance of this thesis work  Measurement of Earth’s field by using fluxgate sensor  Theoretical explanation  Advantages of fluxgate sensor  Experimental Set-up and measurement procedure  Measurement results  Comparison of vehicle signatures and equipotential lines  Interpretations of the results  Discussions  Conclusion  Future prospects

3. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Problem Definition:  With the increase of traffic on the roads the current traffic detection systems(Inductive loops) which are placed just below the earth‘s surface are not reliable.  Finding the appropriate vehicle recognition system. Aim of the Project:  The fluxgate sensor implementation in traffic detection system.  Finding the the appropriate sensor location and its direction of placement.

4. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Earth’s magnetic fieldThe earth’s magnetic field vector

5. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Vehicle disturbance in Earth‘s field: Ferrous object disturbance in uniform field:

6. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Comparison of different magnetic elements with their operational range:

7. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Comparison of low field magnetic sensors with the same resolution:

8. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Sensor Type Measurement Range ResolutionCurrent Consumption Hall sensor±50mT0.1mT20mA Magnetoresistive sensor ± 10mT/ ±1mT200µT/20µT10mA IMS fluxgate sensor±200µT1µT35mA Comparison of different magnetic sensors:

9. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Working Principle of Fluxgate Sensor:

10. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Layout Diagram of FGS1/COB07:

11. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Characteristics :  Two sensor axes are arranged in orthogonal directions.  The differential arrangement of fluxgate system filters out the even harmonics from the output signal.  With the differential arrangement the sensitivity will be twice as that of the single axis fluxgate sensor.  The output voltage is linear.  Low drift in sensitivity.  The excitation current required by ferromagnetic core to drive into saturationregion is 30-35mA.

12. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Advantages:  The sensor is not affected by weather conditions such as rain, fog, snow, wind etc., and dirt.  There is no problem to detect the vehicle even when the vehicle is projected into adjacent lane.  This sensor needs very low maintenance.  With this sensor both moving and standing vehicles can be detected.

13. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Experimental Set-up:

14. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE

15. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE 300 250 200 150 100 50 0 50 100 150 200 250 300 350 Measurement Procedure: 40 60 80 100 120

16. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Offset measurement:

17. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Measurement Results

18. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Measurement Results

19. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Measurement Results

20. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Comparison of magnitude field strength with respect to distance:

21. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Magnitude variation for different depths: Z-40cm depth Z-80cm depth

22. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Z-120cm depth  The sensors in the middle(16cm, -16cm) are showing more deviation and which are away from the center are showing less deviation of the field.  This effect is beneficial when a sensor has to detect vehicles in a single lane of traffic with other lanes present. Magnitude variation for different depths:

23. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Comparison of sensor signatures for different depths:

24. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Comparison of sensor signatures for different depths:

25. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Comparison of sensor signatures for different depths:

26. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Comparison of sensor signatures for different depths:

27. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Comparison of magnetic fields for a depth of 120cm:

28. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Comparison of magnetic fields for a depth of 120cm:

29. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Comparison of magnetic fields for a depth of 120cm:

30. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Comparison of magnetic fields for a depth of 120cm:

31. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Equipotential lines: Figure 21 Figure 22 Analysis of Equipotential lines: –Vehicle presence: Figure 24

32. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE  Signal distortion due to the 50Hz power line cycle  Magnetic noise(Barkhausen noise).  Resistance noise(long cable): Calculated by Nyquist.  The measurements are taken by passing the car in steps of 20cm over the sensors. The position accuracy is ±1cm.  The Passat may not be driven exactly in the middle of the ramp. The variation is ±2.5cm.  Forward and Backward measurements. Accuracy limitations in measurements:

33. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Interpretations of the results: Overlapping of Passat on the signature:

34. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Vehicle Direction:

35. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Vehicle Detection: Positioning the sensor:

36. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Figure28 Advantage of taking Bz for Vehicle Detection: B-Magnitude=√ (B 2 x +B 2 y +B 2 z ) –To get the third-axis field the sensor is to be rotated by 90°.

37. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE  Sensors are to be placed symmetrically.  The waveforms at the outputs of the sensors are identical.  Vehicle’s velocity: Vehicle length calculation:  Velocity and the magnitude variation Vehicle classification: Discussions: Velocity measurement :

38. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Some applications of vehicle presence in daily life:  Car Wash Entry/Exit  Drive-through System  Loading Dock  Gate closing  Traffic Detection  Intelligent parking Lots  Toll Ways

39. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Conclusion: Achieved results:  Analysis of Bx, By, Bz, B-magnitude.  Drawing Equipotential lines.  Sensor which is very close: Earth’s field+ Remanence.  Appropriate depth for the proper signature of the vehicle is 100cm or 120cm.  Analysis of equipotential lines:  z-axis field is suitable for the vehicle detection.

40. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Correlation to Demands of Detection System  Noise correlation technique:  Extract the actual signal from the embedding  Differential arrangement of fluxgate system:  Twice the sensitivity  Power line cycle filter:  Noise is reduced  Signal to noise ratio is improved  With this method of measurement:  Vehicle signature is much accurate

41. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE Future Prospects:  Finding length of the vehicle.  Classification of vehicles.  In this project the magnetic field in x, y, z directions are measured and from those B-magnitude is calculated.  Analyzing the Earth’s magnetic field vector (  ) : Bx, By and Bz  Comparing the results with different vehicles.

42. Sampath Kumar, Uppu Investigation of Magnetic Pattern of Vehicles and Correlation to Demands of Detection Systems 20.10.2004 FH Lausitz/ SE THANK YOU FOR YOUR ATTENTION