Electrical Noise Location System Drew Compston Richard Denney Josh Gordon

2 23 October 2007 Background of Project Identify Angle of Arrival of AM RF Display Information about Incident RF in GUI Build Noise Sources to Test System Expect Total Cost to be $16,228 Noise Source Noise Receiver Computer: Displays GUI and Calculates AoA

3 23 October 2007 Motivation Q-Track Desires System for its QT-400 QT-400 is an RTLS using NFER Operates in AM Frequencies (Pictures from Q-Track User’s Guide Pamphlet, used with permission)

4 23 October 2007 Software Implementation Connect Computer with QT-400 Handle QT-400 Output Design User-friendly GUI Calculate Angle of Arrival (AoA)

5 23 October 2007 Connecting With Computer Communicate through b Wireless Network Set QT-400 Frequency Remotely Listen for Broadcast UDP Packets

6 23 October 2007 Handling Information Information in UDP Packets:  Magnitude of Received Voltage on Each Channel ( R A, R B, R C )  Relative Phase Difference Between Channels A & B and Channels B & C Save QT-400 Output Data in.dat File Graph Using Open-source Software from the Code Project

7 23 October 2007 Graphical User Interface Written in C# Waterfall Plot Calculate AoA Set Parameters

8 23 October 2007 GUI Parameters QT-400 Frequency Graph Start, Stop, Step Frequencies Sweep Time Graph Refresh Rate

9 23 October 2007 Calculating Angle of Arrival QT-400 Has 3 Antennas:  2 Electrically Small Orthogonal Magnetic Loop Antennas (Channels A & C)  1 Electrically Small Electric Whip Antenna (Channel B)

10 23 October 2007 Electrically Small Loop Antennas Complex Voltages on 2 Loops: Null Lobe Radiation Pattern of Electrically Small Loop: Antenna

11 23 October 2007 Virtual Loop Antenna Combine 2 Loops’ Response in Weighted Sum to Create Virtual Loop Oriented in any Direction θ :

12 23 October 2007 Angle of Arrival Algorithm Assume Phase Difference between 2 Loops is either 0° or 180°. Result: Minimize Magnitudes to Obtain Possible AoAs of: Front-Back Ambiguity

13 23 October 2007 Resolving Front-Back Ambiguity In General: Loop Antenna Has 180° Phase Flip Across Each Lobe Result: Combining Loop Response with Whip Response Results in Cardiod Pattern Not Possible with QT-400 Because of Arbitrary, Unknown Phase Offset in Measurements Test to Determine which Phase Measurements Result in Correct AoA to Use

14 23 October 2007 Computer Simulations 3 Antennas Modeled in NEC:  2 Square Loop Antennas (side lengths = 0.01λ)  1 Dipole (whip, length = 0.04λ) Data Exported to MATLAB and Plotted

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17 23 October 2007 Steps in Computing AoA 1. Find Principle Angle ψ ’ (below) Based on Phase Comparison: 2. Add or Subtract 90° to ψ ’ Based on Absolute Phases

18 23 October 2007 Design Testing Create Sinusoids at 1MHz, 1.54MHz, and 1.84MHz with Signal Generator Create Noise Signal with Broadband Random Noise Generator Step Up Signal Strength with Power Amplifier Broadcast Signals with Simple Antenna

19 23 October 2007 Broadband Noise Generator Different Capacitors for Different Frequencies From: J. Williams. A Broadband Random Noise Generator. [Online]

20 23 October 2007 Power Amplifier

21 23 October 2007 Cost Lecture Attendance Weekly Meetings Writing Reports DevelopmentTotal 3 hours/week2 hours/week3 hours/week6 hours/week14 hours/week x$24/hour$336/week x16 weeks$5,376 x3 engineers$16,128 Subtotal$16,128 Parts$100 Total$16,228

22 23 October 2007 Current Status Unable to Connect to QT-400 Software  Program Retrieving Data from QT-400 Completed but Untested  Plotting Software Obtained AoA Algorithm Defined, not yet Implemented in Software Noise Source Circuit Schematics Finalized, Parts yet to be Ordered

23 23 October 2007 Timeline/Future Work 11/2 – Test Noise Source in Lab 11/12 – Fully Functioning GUI and AoA Algorithm 11/19 – Portable Noise Source Completed 11/26 – Test Entire System with Noise Sources 12/7 – Final Design Prototype Completed

24 23 October 2007 Pending Questions Will Algorithm Work on Broadband Noise Source? Can We Account for Multiple Noise Sources at the Same Frequency? Any Others? THANKS FOR YOUR TIME