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CITRIS: The Cosmic Companion for LEO Radio Occultation. P.A. Bernhardt C.L. Siefring J.D. Huba C.A. Selcher Plasma Physics and Information Technology Divisions Naval Research Laboratory Washington, DC 20375 COSMIC Radio Occultation Workshop 21 August 2002 Boulder, Colorado.

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citris the cosmic companion for leo radio occultation

CITRIS: The Cosmic Companion for LEO Radio Occultation

P.A. Bernhardt

C.L. Siefring

J.D. Huba

C.A. Selcher

Plasma Physics and Information Technology Divisions

Naval Research Laboratory

Washington, DC 20375

COSMIC Radio Occultation Workshop

21 August 2002

Boulder, Colorado

computerized ionospheric tomography radio instrument in space citris
Computerized Ionospheric Tomography Radio Instrument in Space (CITRIS)
  • NRL Radio Plasma Sensors in Space
    • ARGOS, PICOSat, C/NOFS, NPSAT1, STPSAT1, COSMIC, ISE/SCITRIS II
    • Radio Beacon Systems
    • NRL Langmuir Probe
  • CITRIS Objectives
    • Global Ionospheric Monitoring
    • Medium Resolution Irregularity Imaging
    • Scintillation Detection and Prediction
    • Radio Science Experiments
  • Conclusions
nrl radio beacon sensors in space
CITRIS on

STPSAT1

(2006)

CERTO/LP

on NPSAT1

(2006)

SCITRIS I

(2006)

NRL Radio Beacon Sensors in Space

CERTO on C/NOFS (2003)

CERTO on ARGOS

CERTO on

PICOSat (2001)

(1999-2001)

CERTO on COSMIC (2005)

ISE/SCITRIS II (2005)

radio beacon sensor timelines
Radio Beacon Sensor Timelines

Satellite

ARGOS

DMSP/S15

PICOSat

STRV-1D

C/NOFS

COSMIC (6)

SCITRIS II

NPSAT1

STPSAT1

NPOESS

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

Calendar Year

beacon sensor instrumentation
Beacon Sensor Instrumentation
  • Space Hardware
    • CERTO Beacon on C/NOFS, COSMIC and NPSAT1
      • 150.012, 400.032, 1066.752 MHz
      • ~1 Watt with No Modulation
    • CITRIS Receiver on STPSAT1
      • Bands at 150, 400 or 401.25, 1067 or 2036 MHz
      • -140 dBm Sensitivity
      • DSP of 10 MHz IF I and Q
      • TEC, S4, sf, FFT and Raw Data Products
    • Langmuir Probe on STPSAT1
  • Ground Support Instruments
    • DORIS Beacon Transmitters (401.25, 2036.26 MHz)
    • TEC and Scintillation Receivers
      • Global Existing Networks at 150/400 MHz (SCINDA, CIDR, CITRIS)
      • New Systems Using 150/400/1067 MHz (South America, India, Pacific)
    • Ground Incoherent Scatter Radars
      • Electron Density Profiles/Field Aligned Irregularities
      • Jicamarca Radio Observatory
      • Arecibo Ionospheric Observatory
tbb certo beacon 3 x 5
TBB/CERTO Beacon (3” x 5”)
  • Tri-Band Beacon RF Outputs
    • 150.012 MHz 27 dBm
    • 400.032 MHz 30 dBm
    • 1066.752 MHz 32 dBmStability: 1 part in 1010 Over 1 Orbit
  • Stability: 1 part in 1010 Over 1 Orbit
  • Input Power: 28 VDC at 12.8 Watts
  • Output Control: 150/400 On/OF

1067 On/OFF

  • Used on C/NOFS, COSMIC, NPSAT1
  • Made by Syntech Microwave Inc.
  • Designed by NRL Codes 6794 and 8131
  • Radiation Resistant to 40 kRad
  • Internal Watch-Dog Timer for SEU
citris receiver for sptsat1
ADC

ADSP-

21060

RF

ADC

GC4014

ADC

Spacecraft

Interface

7.93 cm

[3.119”]

CITRIS Receiver for SPTSAT1

26.99 cm

[10.625”]

Inputs from

Antenna

20.96 cm

[8.25”]

Control

CERTO

12-bits

IF

150 MHz

400 MHz

IF

12-bits

Link

Port

1067 MHz

IF

12-bits

2036 MHz

DORIS

Clock

ACK

SYNC

Serial Out

Serial In

Power Supply

5V DSP

28 Volts

5V ADC

5V RF

slide8
CERTO/TBB Accommodations

on COSMIC

CERTO Beacon

Boom

Magnetometer

Nadir

Reflectors

Trapped Antenna Radiators

scitris i ionospheric instruments
Deployed Arrays

CITRIS Antenna

CITRIS Receiver

STPSAT1

SCITRIS I Ionospheric Instruments

CERTO Three Frequency Monopole Antenna

NPSAT1

Ram Velocity

NRL Langmuir Probe (NLP)

radio sources for ionospheric measurements
Radio Sources for Ionospheric Measurements

VHF/UHF Satellite Beacons in Low Earth Orbit

30 Total

(NIMS, CERTO, …)

L-Band GPS Beacons Globally Distributed

24 Total

UHF/S-Band Ground Beacons Globally Distributed

54 Total

(DORIS)

doris ground beacon contacts 35 o inclination 265 total contacts over 24 hours
(c)

(b)

Contact Duration (772 Seconds Maximum)

Site Contacts (8 Max.)

DORIS Ground Beacon Contacts (35o Inclination)265 Total Contacts Over 24 Hours
multi direction geometry for scintillation and tec measurements
CERTO Beacon

Transmitter

on COSMIC

Ionosphere

N

Ground

Receivers

DORIS

Transmitters

S

CITRIS Receiver

on STPSAT1 and

ISE/SCITRIS II

LEO Orbit

MULTI-DIRECTION GEOMETRYFOR SCINTILLATION AND TEC MEASUREMENTS
tec scintillation and tomography
TEC, Scintillation and Tomography

CERTO Beacon on COSMIC and NPSAT1

Orbit

Irregularity

140/400/1067 MHz Receiver

tec scintillation and tomography15
TEC, Scintillation and Tomography

CERTO Beacon on NPSAT1 and COSMIC

Orbit

Irregularity

CITRIS Receiver on STPSAT1

DORIS

140/400/1067 MHz Receiver

401.25/2036.25 MHz Transmitter

scintillation and ionospheric tomography radio instrument in space scitris i
CERTO/LP on NPSAT1

Tandem Operations

Scintillation and Ionospheric TomographyRadio Instrument in Space (SCITRIS I)

CITRIS on STPSAT1

RF Link

citris certo overview
Vertical TEC

(1016 m-3)

CITRIS/CERTO OVERVIEW

Program Goals

  • Detect when and where radiowave propagation through the ionosphere is adversely affected by scintillation and refraction
  • Provide a global map of ionospheric densities and irregularities

NRL SAMI3

TEC Predictions

SCINTMOD

Scintillation Predictions

radio beacon science experiments
Radio Frequency Interpolation Test (C/S/N)

Multiple Frequency Transmission

Measurements at Frequencies 150 and 1067 MHz

Predictions for Arbitrary Frequency

Validation Using Measurements at 400 MHz

In-Situ Probe for Propagation Estimation (N/S)

Langmuir Probe Detection of Electron Density Fluctuations

From Langmuir Probe Estimate Phase Screen Model

Compute Scintillation Amplitude at Selected Frequencies

Validate Phase Screen Model

Mode Coupling: Quasi-Transverse (QT) Propagation (C/S/N)

Radio Science Investigation Near Magnetic QT Points

O-Mode Transmission

X- or O-Mode Reception

Diagnostic of Ionosphere Near QT Point

Single Frequency Reciprocity Tests (C/S/N)

Multiple frequencies (150, 400, and 1067 MHz)

Common Paths for Uplinks and Downlinks

Implementation: T/R Pulsing at 10 ms With PN Sequence

Global Ionospheric Mapping (S/C)

Continuous Monitoring of the 6 COSMIC Space Beacons and 54 DORIS Ground Beacons

401.25 and 2036.25 MHz Reception

TEC and Scintillation Measurements in Space

Faraday Rotation and Differential Doppler Imaging (N/S/C)

High Resolution Local Mapping

Ground Measurement

Polarization Angle at Each Frequency

Differential Phase Between Frequency Pairs

Multiple Frequencies (150, and 400 MHz)

Tomography Using TEC and Faraday Content

Radio Beacon Science Experiments

Note: C = COSMIC S = SPTSAT1 N = NPSAT1

slide19
Space-to-Ground Propagation

Through an Ionospheric Irregularity

Downward

Ionospheric Propagation Distortion at 400 MHz

Amplitude (dB) Phase (Radians)

East-West Distance (km)

slide21
Electron Density (105 cm-3)

0 2 4 6 8

STPsat1 Position

15

0

Amplitude (dB)

-15

Plume

Altitude (km)

Ne Peak

Predictions of Scintillations from a CITRIS Receiver at 800 km Altitude

Zonal Distance (km)

irregularity measurements and radio scintillations
Irregularity Measurementsand Radio Scintillations

Sampled Density, ne

Electron Density (105 cm-3)

Sampled Fluctuations, dne/ne

Ne Peak

Plume

Zonal Distance (km)

VHF Ground Level:

Large Scintillations

Langmuir Probe at 550 km

Amplitude (dB)

-30 dB Signal Dropouts

Zonal Distance (km)

conclusions
Conclusions
  • The 6 COSMIC satellites launched in late 2005 will be supported for ionospheric studies by the NPSAT1 and STPSAT1 vehicles to be launched in tandem in January 2006
  • These satellites, which are sponsored by the Air Force Space Test Program and the Naval Post Graduate School in Monterey, contain radio and in situ diagnostic instruments to study the ionosphere.
  • The CITRIS receiver provides rare opportunities to perform two-way propagation experiments between space and ground and one way experiments from space-to-space.
  • Current Experiments Cover (1) Global Ionospheric Mapping, (2) Fundamental Radio Propagation Studies, and (3) Scintillation Observations and Prediction.
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