VLF InterferometerVLF 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 InterferometerPurpose 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 V2.0Interferometer V2.0

Validate Sampling method

Test Connection to CF media.

Fix any gotchas

Cleanup design Improve Stability Get ready for

Production

Version 1.0 Version 2.0

Arrangement of InterferometerArrangement of Interferometer

Interferometer CapabilitiesInterferometer 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 ReceiverBlock Diagram of Receiver

Antennas

Preamplifier

Line Receiver Clipper Anti-aliasing LPF Filter

16-Bit A/D (250 ksps)

Control Logic (FPGA)

CPU (i386)

UT+ Oncore GPS

1GB Storage Device

Modem?

Preamp

Line Receiver

Time SynchronizationTime Synchronization

1PPS GPS Clock

Temp. Controlled

Crystal Osc. ~10MHz

FPGA 16-Bit A/D

Control Signals

i386

Data BusControl Signals

Main EquipmentMain 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!

PreampPreamp

PreampPreamp

Preamp CardsPreamp Cards

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

Amplifies and filters signal.Output driver with a transformer.

Line ReceiverLine Receiver

MotherboardMotherboard

MotherboardMotherboard

Voltage regulation.Mounts for CPU and GPS cards.FPGA for glue logic.ISA type slots for adapter cards.

CPU CardCPU 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 CardGPS Card

Motorola Encore GPS card.Small form factor.For timing use, +/- 500ns timing accuracy.Serial I/O

Filter CardFilter Card

Instrumentation Amplifier – differential input to single ended output.

Selectable 8 pole or 16 pole Chebyshev filter.

Selectable output gain from unity to 40dB.

Sample FilterSample Filter

CF Storage CardCF 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 CardSampling 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.

LocationsLocations

HAARP– Near transmitter– Power lines nearby

Lake Louise & Paxton– ~45 Minutes away– In the middle of no-where– No power lines nearby– Low Noise

HAARP SetupHAARP Setup

HAARP SetupHAARP Setup

Lake LouiseLake Louise

Lake LouiseLake Louise

Lake LouiseLake Louise

Lake LouiseLake Louise

Lake LouiseLake Louise

HAARP SU DataHAARP SU Data

HAARP SU DataHAARP SU Data

HAARP SU DataHAARP SU Data

Lake Louise SU DataLake Louise SU Data

Lake Louise SU DataLake Louise SU Data

Lake Louise SU DataLake Louise SU Data

HAARP AU DataHAARP AU Data

Lake Louise AU DataLake Louise AU Data