BME/CENG/ELEC/SENG 499
Design Project

 

BME/CENG/ELEC/SENG 499 Projects

Supervisor: Paul Kraeutner, pkraeutner@shaw.ca (March 24, 2014)

PK1 Depth Sounder with NMEA Output and using Dynamic Binary Coding (Hardware)

This project is in conjunction with Ping DSP Inc. and is intended to fulfill a need for a small 2 channel depth sounder that runs from 5 volts only and continuously outputs a simple NEMA ASCII string with depth (i.e. range) information. The cost of the finished device should be less than $50.

In order to run from 5 volts and to keep the device simple, it is proposed that a binary coded transmit waveform be employed and the acoustic transducer driven directly from 5 volts. On receive; the acoustic echo will be amplified to produce a 5 volt square wave output that can be clocked into the receiver processor.

The receive processor correlates the binary receive waveform with the binary transmit code and the time of arrival of the correlation peak is used to determine the range to the seafloor. The computed depth is output serially in a NMEA format.

In order to compensate for signal attenuation with increasing range to the seafloor, it is proposed that the binary code used for transmit is dynamically increased in length. For example, on power up the device begins by transmitting it's shortest binary code. If the correlator does not produce the expected peak value the code is lengthened and the process repeated. Once the bottom is detected, the code length is increased or decreased according to increasing or decreasing depth values.

The project should allow for 2 channel operation but only one channel need be implemented and tested. The project should also allow for operation over the frequency range of 200kHz to 2MHz but only one frequency need be implemented and tested. The exact frequency of operation will be specified at the start of the project.

The project is ideally suited to a group of 2 or possibly 3 students interested in sonar systems and signal processing. The project will likely require a microcontroller such as an Arduino and possibly a small FPGA. Firmware requirements for the project can be divided into two parts:

  1. Controller firmware for overall sounder control and data output streaming
  2. FPGA firmware for binary receive and correlation processing

For demonstration purposes, the NMEA strings can be parsed and displayed on a PC.

PK2 Sound Velocimeter with NMEA Output (Hardware)

This project is in conjunction with Ping DSP Inc. and is intended to fulfill a need for a small sound velocimeter to measure underwater sound speed and provide a continuous NMEA ASCI output of the result in m/s. The cost of the finished device should be less than $100.

The operating frequency for the project will be approximately 2MHz and it is up to the students to propose the exact sound velocity measurement method and design for the device.

The project is ideally suited to a group of 3 or possibly 4 students interested in sonar systems and signal processing. The project will likely require a microcontroller such as an Arduino and possibly a small FPGA. Design requirements for the project can be divided into two parts:

  1. System design and estimation of acoustic sound speed range requirements
  2. Hardware design (proto board, or dev kit, or pcb - to be proposed)
  3. Firmware design (microcontroller and/or FPGA)
  4. Mechanical Design (materials, transducer, etc)

For demonstration purposes, the NMEA strings can be parsed and displayed on a PC. The velocimeter can be submerged in fresh water versus salt water or cold (iced) water versus warm water. A demonstration of precision could be accomplished with water a lightly different temperatures (a digital thermometer and PC based sound velocity calculation could be used to help here).