Radio-science experiments with the Enhanced Polar Outflow Probe satellite payload using its RRI, GAP and CERTO instruments H.G. James, CRC, Ottawa, Canada P.A. Bernhardt, NRL, Washington, U.S.A. R.B. Langley, U. New Brunswick, Fredericton, Canada C.L. Siefring, NRL, Washington, U.S.A. A.W. Yau, U. Calgary, Calgary, Canada URSI GA2005 New Delhi, 23-29 October 2005 Session G04, Paper COM7-01742-2005, file URSI2005_James2.ppt 1
Enhanced Polar Outflow Probe (e-pop) Science The 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 auroral currents on plasma outflow and those of plasma microstructures on radio propagation. Hear also: Yau et al. paper, Session G05b, Friday 28 Oct 2
epop Instrument Institute e-pop on IRM Imaging Rapid-scanning Mass spectrometer U. Calgary CASSIOPE SEI Suprathermal Electron Imager U. Calgary NMS Neutral Mass and Velocity Spectrometer ISAS, Japan FAI Fast Auroral Imager U. Calgary MGF MaGnetic Field Instrument Magnametrics GAP GPS Attitude, Position, occultation experiment U. New Brunswick CERTO Coherent EM Radiation tomography experiment Naval Research Laboratory,USA RRI Radio Receiver Instrument Comm. Research Centre, Ottawa 3
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 4
epop radio-science instruments GAP - GPS Attitude, Position, occultation experiment Richard Langley, U. New Brunswick. CERTO - Coherent EM Radiation tomography experiment Paul Bernhardt, Naval Research Laboratory, USA. RRI Radio Receiver Instrument Gordon James, Communications Res. Centre, Ottawa 5
Total electron content (TEC) Phase path Φ = k.d kd = 2πfnd/c (1-f p2 /2f 2 )2πfd/c. Relation of plasma freq. to electr. density : f p2 = CN e. Φ 1 = (1-f p2 /2f 1 )2πd/c = (1- CN e /2f 1 )2πd/c. Measure Φ 1 at f 1 and Φ 2 at f 2. Then (Φ 1 Φ 2 )cf 1 f 2 /[πc(f 1 -f 2 )] - 2f 1 f 2 d/c= N e d EC m -2 6
Occultation for atmospheric tomography 7
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-Occultation Electron density profiles in the ionosphere and plasmasphere, antenna pointed in anti-ram direction. GAP-Attitude Position, 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. 8
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 LNA LNA LNA LNA LNA/ SWITCH BOX GPS #0 GAP-A GPS #1 GAP-A GPS #2 GAP-A GPS #3 (SPARE) Async serial Power PPS Error Async serial Power PPS Error Async serial Power PPS Error Async serial Power PPS Error Interface Card STATUS COMMAND SCIENCE_DATA SCIENCE_CLOCK PACKET_SYNC 1 PPS Asycnhrounous Serial Sycnhrounous Serial DHU Thermistor(s) GAP-O and GAP-A functions a single instrument CERTO Filter LNA GPS #4 GAP-O Async serial Power PPS Error 3 Analog Monitor(s) Mode Control 3 Antenna Control COTS components used in design (i.e. no rad-hard parts) +12V -12V +3.3V +2.5V Return GAP Power Supply Card +28V PCU Spacecraft Controller 9
epop radio-science instruments GAP - GPS Attitude, Position, occultation experiment Richard Langley, U. New Brunswick. CERTO - Coherent EM Radiation Tomography experiment Paul Bernhardt, Naval Research Laboratory, USA. RRI - Radio Receiver Instrument Gordon James, Communications Res. Centre, Ottawa. 10
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 11
Tomographic Reconstruction Geometry Satellite 12 Reconstruction Plane Receiver Chains
TEC Derived from a Radio Beacon Z j, j k 2 =0 1 2 3 4 5 6 7 8 9 10 Δx 1 n ij Δz D ij (k 1,k 2 ) Δx n 21 n Δx 11 n 12 2 k 1 =0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 13 X i, i
Tomographic images of Travelling Ionospheric Disturbances Tsykada transmissions to Sodankylä Observatory tomography chain (www.sgo.fi/data/tomography) 06:00 09:00 12:00 15:00 UT See also Session G01: Imaging of the ionosphere, 27 & 29 Oct. 14
epop radio-science instruments GAP - GPS Attitude, Position, occultation experiment Richard Langley, U. New Brunswick. CERTO - Coherent EM Radiation tomography experiment Paul Bernhardt, Naval Research Laboratory, USA. RRI - Radio Receiver Instrument Gordon James, Communications Res. Centre, Ottawa. 15
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 auroral processes. 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 ionospheric heaters. 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. 16
CASSIOPE/ePOP flies over transmitters History during pass of wave parameters shows variations in: Amplitude, DOA, Doppler shift and time delay 17
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 18
Antennas on CASSIOPE RRI monopoles GAP 2-Frequency Occultation Antenna CERTO dipole mast 19
Examples of coordinated experiments 20
Joint CERTO and GAP Operations with epop From GPS Satellite Ground Receivers
Ground-satellite studies of latitudinally periodic TID structure 22
Coordinated epop-spear subjects 23
HAARP ELF-VLF Generation Experiments with epop epop Wave and particle diagnostics >325 km 24
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. f p << f c 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. 25