Vlf interferometer
1 / 38

VLF Interferometer - PowerPoint PPT Presentation

  • Uploaded on

VLF Interferometer. Defense University Research Instrumentation Program (DURIP). Project Advisor: Umran Inan Project Team: Jeffrey Chang, Katie Braden, Timothy Chevalier, Andrew Park, Joseph Payne. What Is the Interferometer?.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about 'VLF Interferometer' - justina-pearson

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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Vlf interferometer

VLF Interferometer

Defense University Research Instrumentation Program (DURIP)

Project Advisor: Umran Inan

Project Team: Jeffrey Chang, Katie Braden, Timothy Chevalier, Andrew Park, Joseph Payne

What is the interferometer
What Is the Interferometer?

  • Nine element array of time synchronous receivers.

  • Capable of simultaneous recording in 3 channels, like an expensive VCR.

  • Low power, battery operated, standalone units.

  • Modular design for easy upgrade.

Purpose of interferometer
Purpose of Interferometer

  • Measure near field of HAARP modulated electrojet currents.

    • Determine spatial distribution of currents.

    • Help to maximize ELF/VLF wave production.

  • Standalone receiver that can truly be deployed anywhere anytime.

Interferometer v2 0

Validate Sampling method

Test Connection to CF media.

Fix any gotchas

Cleanup design

Improve Stability

Get ready for Production

Interferometer V2.0

Version 1.0

Version 2.0

Interferometer capabilities
Interferometer Capabilities

  • Capture from ~100 Hz to ~10 kHz.

    • Upper bound is largely variable by changing filter and sample rate.

  • Sensitivity of 1.5*10-6 v/m-Hz-1/2 at 1khz.

  • Low power consumption, ~6W.

  • Store 1 GB of data.

Block diagram of receiver
Block Diagram of Receiver


Line Receiver


Anti-aliasing LPF Filter


16-Bit A/D (250 ksps)


1GB Storage Device

CPU (i386)

Control Logic (FPGA)

UT+ Oncore GPS


Line Receiver

Time synchronization
Time Synchronization

1PPS GPS Clock

Control Signals


16-Bit A/D

Temp. Controlled Crystal Osc. ~10MHz

Control Signals

Data Bus


Main equipment
Main Equipment

  • Tern i386 controller.

  • IBM Microdrive.

  • Motorola Oncore UT+.

Equipment cont
Equipment Cont.

  • 1 x 6V, 189 A-Hr Batteries

    2 x 12V, 55 A-Hr Batteries

  • Laptop.

  • Wagon!

Preamp cards
Preamp Cards

  • Matches the impedence of the square loop antenna with a transformer.

  • Amplifies and filters signal.

  • Output driver with a transformer.


  • Voltage regulation.

  • Mounts for CPU and GPS cards.

  • FPGA for glue logic.

  • ISA type slots for adapter cards.

Cpu card
CPU Card

  • Manufactured by Tern.

  • I386 u-controller with lots of goodies…

  • Two serial lines, one for programming, one for LCD display and GPS.

  • 16 Bit data bus, 7 Bit Addressing (but word access only)

  • Port pins as CS for ADC or CF card.

Gps card
GPS Card

  • Motorola Encore GPS card.

  • Small form factor.

  • For timing use, +/- 500ns timing accuracy.

  • Serial I/O

Filter card
Filter Card

  • Instrumentation Amplifier – differential input to single ended output.

  • Selectable 8 pole or 16 pole Chebyshev filter.

  • Selectable output gain from unity to 40dB.

Cf storage card
CF Storage Card

  • CF connector, capable of docking with both Type I or Type II CF cards.

  • CF cards in IDE mode.

  • Otherwise, nothing special.

  • Future version might have two flash card slots on it.

Sampling card
Sampling Card

  • 3 LTC1606 ADC chips, simultaneous sampling (rated @ 250 ksps each).

  • Sampling controlled by FPGA, with CS from processor.

  • 16 bit tri-state buffers as hacked remedy to power problem

  • Temperature controlled oscillator…for accurate timing.



Near transmitter

Power lines nearby

Lake Louise & Paxton

~45 Minutes away

In the middle of no-where

No power lines nearby

Low Noise