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Electrical Noise Location System. Drew Compston Richard Denney Josh Gordon. 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. Computer: - PowerPoint PPT Presentation
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Electrical Noise Location System
Drew Compston
Richard Denney
Josh Gordon
223 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
NoiseSource
Noise
Receiver
Computer:Displays GUI andCalculates AoA
323 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)
423 October 2007
Software Implementation
Connect Computer with QT-400 Handle QT-400 Output Design User-friendly GUI Calculate Angle of Arrival (AoA)
523 October 2007
Connecting With Computer
Communicate through 802.11b Wireless Network
Set QT-400 Frequency Remotely Listen for Broadcast UDP Packets
623 October 2007
Handling Information
Information in UDP Packets:Magnitude of Received Voltage on Each
Channel (RA, RB, RC)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
723 October 2007
Graphical User Interface
Written in C# Waterfall Plot Calculate AoA Set Parameters
823 October 2007
GUI Parameters
QT-400 Frequency
Graph Start, Stop, Step Frequencies
Sweep Time Graph Refresh
Rate
923 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)
1023 October 2007
Electrically Small Loop Antennas
1801
111
~ jeAA 2
22
~ jeAA
Complex Voltages on 2 Loops: Null
NullLobe Lobe
Radiation Pattern of Electrically Small Loop:
01 Antenna
1123 October 2007
Virtual Loop Antenna
sincos)(~
2121
jj eAeAA
Combine 2 Loops’ Response in Weighted Sum to Create Virtual Loop Oriented in any Direction θ:
sincoscoscos
sinsincossinarctan
~
2211
2211
AA
AAA
2sin)cos(sincos~
212122
222
1 AAAAAA
1223 October 2007
Angle of Arrival AlgorithmAssume Phase Difference between 2 Loops is either 0° or 180°. Result:
180,)sincos(
0,)sincos()(
~
2121
2121
2
1
j
j
eAA
eAAA
Minimize Magnitudes to Obtain Possible AoAs of:
180,2
arctan
0,2
arctan
212
1
212
1
A
A
A
A
Front-Back Ambiguity
1323 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
1423 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
1523 October 2007
1623 October 2007
1723 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
180,arctan
0,arctan
BCABA
C
BCABA
C
R
R
R
R
1823 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
Signal/Noise
Generator
Power Amplifier
Broadcast Antenna
1923 October 2007
Broadband Noise Generator
Different Capacitors for Different Frequencies
From: J. Williams. A Broadband Random Noise Generator. [Online]http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1154,C1009,C1026,P1476,D4262
2023 October 2007
Power Amplifier
1
3X1IRF510
RFC50u
2
C10.1u
RL250
R21k
R3200
5
C20.1u
4
SigGen
Rs50
12
VccVcc
2123 October 2007
CostLecture Attendance
Weekly Meetings
Writing Reports
Development Total
3 hours/week 2 hours/week 3 hours/week 6 hours/week 14 hours/week
x$24/hour $336/week
x16 weeks $5,376
x3 engineers $16,128
Subtotal $16,128
Parts $100
Total $16,228
2223 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
2323 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
2423 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