1 / 57

User Constructed Sonar Equipment

User Constructed Sonar Equipment. Presented to PSUBS Convention 2004. Sonar Principles. Basic Concepts Transducers Ping generation Ping reception Post-ping processing Construction and testing. Sonar Principles. Basic Concepts Transducers Ping generation Ping reception

anne
Download Presentation

User Constructed Sonar Equipment

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. User Constructed Sonar Equipment Presented to PSUBS Convention 2004

  2. Sonar Principles • Basic Concepts • Transducers • Ping generation • Ping reception • Post-ping processing • Construction and testing

  3. Sonar Principles • Basic Concepts • Transducers • Ping generation • Ping reception • Post-ping processing • Construction and testing

  4. Basic Sonar Concepts • Generate a signal at some frequency f0 • Drive an transducer at f0 for a short duration of time generating a “ping” • Allow the sound waves generated to propagate outward at the speed of the medium Vm • Receive the return echo signal measuring the time of flight from transmission to reception Tf • Calculate the distance to target, D = ( Tf · Vm ) / 2

  5. Speeds of Sound vm0 Degrees Celsius [1] • Air 332 m/s 1,090 f/s • Fresh water 1,404 m/s 4,610 f/s • Sea water 1,440 m/s 4,730 f/s • Copper 3,560 m/s 11,680 f/s • Iron 5,130 m/s 16,830 f/s

  6. Sonar Considerations • Attenuation of signal by water • Spherical radiators • Sonar patterns • Choice of frequency • Sensitivity of receiver • Types of transducers

  7. Attenuation of Sound Through Water [2] • Absorption Roughly Related to frequency squared • Scattering Signal scatters use to foreign materials in the water

  8. Sonar Considerations • Attenuation of signal by water • Spherical radiators • Sonar patterns • Choice of frequency • Sensitivity of receiver • Types of transducers

  9. Spherical Sound Radiation • Sound intensity: I = Power / Area (W/m2) • Where area of a sphere = 4pr2 • Same power through any radius (r) we can imagine, with the source in the center • Let PT = Total power through any radius (r) • Therefore: I1 = PT / 4pr12 and I2 = PT / 4pr22 • Combining we have: I1 / r12 = I2 / r22 • We have: I2 = (r12 / r22) I1 or I2 = (r1/ r2) 2 I1 • Conclusion: Intensity of sound drops off with the square of the distance (r) from the source

  10. Sonar Considerations • Attenuation of signal by water • Spherical radiators • Sonar patterns • Choice of frequency • Sensitivity of receiver • Types of transducers

  11. Sonar Considerations • Attenuation of signal by water • Spherical radiators • Sonar patterns • Choice of frequency • Sensitivity of receiver • Types of transducers

  12. Sonar Considerations • Attenuation of signal by water • Spherical radiators • Sonar patterns • Choice of frequency • Sensitivity of receiver • Types of transducers

  13. Sonar Considerations • Attenuation of signal by water • Spherical radiators • Sonar patterns • Choice of frequency • Sensitivity of receiver • Types of transducers

  14. Sonar Principles • Basic Concepts • Transducers • Ping generation • Ping reception • Post-ping processing • Construction and testing

  15. Transducers • Sonar transducer facts • Beam Angle • Piezoelectric principles • Piezoelectric ceramics • Ring and disk transducers elements • Piezoelectric modes • Typical piezoelectric ceramics • Fish finder transducers • Available specialty transducers

  16. Sonar Transducer Facts • Transducers convert electrical signals to sound. • Transducers convert sound into electrical signals. • Most transducers send and receive best at one characteristic frequency f0. • Most small sonar transducers are of a piezoelectric form. • Most piezoelectric materials for sonar application are ceramics.

  17. Beam Angle

  18. Piezoelectric Principles [3] Voltage Creates DW DW Generates Voltage DW = Change in Thickness

  19. Piezoelectric CeramicsManufactured in a Variety of Shapes [4]

  20. Ring and Disk Transducer Elements Rings Helps Eliminate Lateral Resonance Modes Thin Discs Showing Conductive Coating

  21. Piezoelectric Modes [5]

  22. Piezoelectric Modes [5]

  23. Piezoelectric Modes [5]

  24. Piezoelectric Modes [5]

  25. Typical Piezoelectric Ceramics [6] Channel Industries, Inc.

  26. Relatively Inexpensive Encapsulated Wiring Attached Wide or Narrow Cone Locally Available Little Choice of Resonate Frequencies Unknown Piezoelectric Material Used Unknown Electrical Properties of Material Fish Finder Transducers Advantages Disadvantages

  27. Fish Finder Transducers(Eagle [7]) Transom Mount Cylinder Thru Hull

  28. Available Specialty Transducers [7] Thru Hull Bronze Thru Hull Plastic Trolling Motor Mount

  29. Sonar Principles • Basic Concepts • Transducers • Ping generation • Ping reception • Post-ping processing • Construction and testing

  30. Ping Generator System

  31. Ping Generator Module

  32. 192-KHz Frequency Generator Section

  33. Alternative Design

  34. Ping Driver Circuit • Amplifies 192-KHz Signal from Generator and Drives Transducer • Generates Drive Only when Ping Enable is Active • Multiplexes Sonar Transducers if System Requires

  35. Ping Driver Circuit

  36. Ping Driver Module

  37. Sonar Principles • Basic Concepts • Transducers • Ping generation • Ping reception • Post-ping processing • Construction and testing

  38. Ping Reception

  39. Ping Receiver Module

  40. Sonar Principles • Basic Concepts • Transducers • Ping generation • Ping reception • Post-ping processing • Construction and testing

  41. Post-ping Processing Options • Sample return analog for feed to computer or microcontroller. • Use analog means of measuring time between ping and the breaking of a return threshold level. • Be creative with your own methods of monitoring returned amplitude vs time!

  42. Sonar Principles • Basic Concepts • Transducers • Ping generation • Ping reception • Post-ping processing • Constructionand testing

  43. Construction and Testing • Pressure Housing • Electronic assembly • Modules • Transducer array • Testing

  44. Pressure Housing

  45. Electronics Assembly Microcontroller Board

More Related