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Radio-science experiments with the Enhanced Polar Outflow Probe satellite

payload using its RRI, GAP and CERTO instruments

H.G. James, CRC, Ottawa, CanadaP.A. Bernhardt, NRL, Washington, U.S.A.R.B. Langley, U. New Brunswick, Fredericton, CanadaC.L. Siefring, NRL, Washington, U.S.A.A.W. Yau, U. Calgary, Calgary, Canada

URSI GA2005New Delhi, 23-29 October 2005

Session G04, Paper COM7-01742-2005, file URSI2005_James2 .ppt

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Enhanced Polar Outflow Probe (e-POP) ScienceThe scientific objectives of e-POP

are to • quantify the micro-scale

characteristics of plasma outflow and related micro- and meso-scale plasma processes in the polar ionosphere,

• explore the occurrence morphology of neutral escape in the upper atmosphere, and

• study the effects of auroralcurrents on plasma outflow and those of plasma microstructures on radio propagation.

Hear also: Yau et al. paper, Session G05b, Friday 28 Oct

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e-POP on CASSIOPE

Comm. Research Centre, Ottawa

Radio Receiver InstrumentRRI

Naval Research Laboratory,USA

Coherent EM Radiation tomography experimentCERTO

U. New BrunswickGPS Attitude, Position, occultation experimentGAP

MagnametricsMaGnetic Field InstrumentMGF

U. CalgaryFast Auroral ImagerFAI

ISAS, JapanNeutral Mass and Velocity SpectrometerNMS

U. CalgarySuprathermal Electron ImagerSEI

U. CalgaryImaging Rapid-scanning Mass spectrometerIRM

InstituteePOP Instrument

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CASSIOPE Mission Parameters

• Inclination: 80 Degrees• Orbit: 325 x 1500 km• Lifetime: > 1 Year• Initially: Arg. of Perigee = 270°; Noon-midnight• Launch: Early 2008• Fast attitude slews • 100-MHz bandwidth data downlink

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ePOP radio-science instrumentsGAP - GPS Attitude, Position, occultation experiment

Richard Langley, U. New Brunswick.

CERTO - Coherent EM Radiation tomography experimentPaul Bernhardt, Naval Research Laboratory, USA.

RRI Radio Receiver InstrumentGordon James, Communications Res. Centre, Ottawa

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Total electron content (TEC)Phase path Φ = k.d ≈ kd = 2πfnd/c ≈ (1-fp

2/2f 2)2πfd/c.

Relation of plasma freq. to electr. density : fp2 = CNe .

Φ1 = (1-fp2/2f1)2πd/c = (1- CNe /2f1)2πd/c .

Measure Φ1 at f1 and Φ2 at f2 . Then (Φ1 – Φ2 )cf1f2 /[πC(f1-f2 )] - 2f1f2d/C= Ned ≡EC m-2

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Occultation for atmospheric tomography

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GAP-AttitudePosition, velocity, attitude, and time can be

determined in real time. Position to 100 m, velocity to 10 m/s, attitude to 5°and time to 8 µs.

High-rate (up to 20 Hz) measurements on setting (occulted) GPS satellites together with measurements from non-occulted satellites down linked to ground for analysis.

GAP-OccultationElectron density profiles in the ionosphere and

plasmasphere, antenna pointed in anti-ram direction.

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GAP Functions• Instrument consists of:

– An Interface card– Power Supply card– 5 Commercial GPS cards

(Includes one spare)– 5 GPS antennas and LNAs– Antenna RF and LNA DC

switches– A CERTO Filter

• GAP-O and GAP-A functions a single instrument

• COTS components used in design (i.e. no rad-hard parts)

LNA/SWITCH

BOX

LNA

GPS #0GAP-A

InterfaceCard

DHU

Async serial

SpacecraftController

1 PPS

Power

PPS

Error

GPS #1GAP-A

Async serial

Power

PPS

Error

LNA GPS #2GAP-A

Async serial

Power

PPS

Error

GPS #3(SPARE)

Async serial

Power

PPS

Error

LNA

GPS #4GAP-O

Async serial

Power

PPS

Error

Antenna Control

SycnhrounousS

erial

STATUS

COMMAND

SCIENCE_DATA

SCIENCE_CLOCK

PACKET_SYNC

Thermistor(s)

Analog Monitor(s)

PCU

Asycnhrounous

Serial

LNA

LNA

GAP PowerSupply Card +28V

+12V

-12V

+3.3

V

+2.5

V

Ret

urn

Mode Control 3

3CERTO

Filter

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ePOP radio-science instrumentsGAP - GPS Attitude, Position, occultation experiment

Richard Langley, U. New Brunswick.

CERTO - Coherent EM Radiation Tomography experimentPaul Bernhardt, Naval Research Laboratory, USA.

RRI - Radio Receiver InstrumentGordon James, Communications Res. Centre, Ottawa.

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CERTO subjects of investigation

TEC and Scintillations• Tomographic Images

– Electron Density Maps– Phase Screen Reconstruction

• Scintillation Parameters– Irregularity Detection (~ 1 km scale sizes)– Amplitude and Phase Scintillation Indices

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Tomographic Reconstruction Geometry

Satellite

Receiver C

hains

Reconstruction

Plane

Satellite

Receiver C

hains

Reconstruction

Plane

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nij

TEC Derived from a Radio Beacon

Xi, i

Zj, j

k1 =0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

k2 =0 1 2 3 4 5 6 7 8 9 10Δx1

Δx2

Δx

Δz

Dij(k1,k2)

n11 n12

n21

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Tomographic images of TravellingIonospheric Disturbances

↑

06:00 09:00 12:00 15:00 UT

Tsykada transmissions toSodankylä Observatory tomography chain

See also Session G01: “Imaging of the ionosphere”, 27 & 29 Oct.

(www.sgo.fi/data/tomography)

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ePOP radio-science instrumentsGAP - GPS Attitude, Position, occultation experiment

Richard Langley, U. New Brunswick.

CERTO - Coherent EM Radiation tomography experimentPaul Bernhardt, Naval Research Laboratory, USA.

RRI - Radio Receiver InstrumentGordon James, Communications Res. Centre, Ottawa.

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E-POP Radio Receiver Instrument Science

• 10 Hz to 3 MHz: Measure the electric fields of spontaneous waves, for understanding spontaneous radio emissions created by auroralprocesses. These measurements will be made in concert with onboard particle detectors.

• 1 kHz to 18 MHz: Measure the electric fields of waves created by ground transmitters, such as ionosondes, HF radars and ionosphericheaters. These transionospheric propagation experiments will investigate

• a) the dynamics of density structure and the metrology of coherent scatter from it, and

• b) the nonlinear plasma physics of the HF-modified ionosphere.

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CASSIOPE/ePOP flies over transmitters

History during pass of waveparameters showsvariations in:

Amplitude, DOA,Doppler shiftand time delay

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Radio Receiver Instrument Parameters

• Frequency range: 10 Hz – 18 MHz• Signal threshold (LSB): 0.3 V• Thermal noise(10-1000Hz): 18 V• Maximum signal for linearity: 1.3 V• Sample size: 12 bits• Max. sample rate/channel: 60,000 s-1

• Number of channels: 4• Antennas: 4 tubular 3-m monopoles • Absolute time stamp (GPS): ± 8 s

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Antennas on CASSIOPE

GAP 2-FrequencyOccultation Antenna CERTO dipole mast

RRI monopoles

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Examples of coordinated experiments

Joint CERTO and GAPOperations with ePOP

From GPS Satellite

Ground Receivers

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Ground-satellite studies of latitudinally periodic TID structure

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Coordinated ePOP-SPEAR subjects

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ePOP Wave and particle diagnostics

>325 km

HAARP ELF-VLF Generation Experiments with ePOP

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Concluding rationale for space radio science

World emphasis is on regional/global scale, assimilation of data sets.All technologies and methodologies are not mature.

Need persists to understand microscale physics (bricks and mortar).Active and controlled wave experiments are still needed.Physics of unbounded low density plasmas.

fp << fc deserves attention, not feasible in lab plasmas.ePOP: exploits niche opportunities in Canada and elsewhere.

holds considerable potential for inter-instrument investigations works with gnd. facilities: imaging, scatter, nonlinearities. maintains and improves space-borne radio capability.