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Radio-science experiments with the Enhanced Polar … · 1 Radio-science experiments with the...
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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.