ATMOZ-GPS Sounding the Earth's Atmosphere and Ionosphere

Orbit with the La Trobe Eagle
La Trobe University is a major facility in the plans for the Australian Cooperative Research Centre for Satellite Systems (CRCSS).
To establish the CRCSS, the Federal government has already pledged $20 million over seven years.
Plans call for the CRCSS to launch its first satellite, FedSat 1 in time for the centenary of Federation in 2001.
La Trobe is the only Victorian university that is in the CRCSS.
Once the CRCSS is formally established at the end of 1997, there will be new opportunities in Space Science and Technology for both undergraduate and research students. Subject to the final exchange of contracts formally establishing the CRC for Satellite Systems, top-up scholarships will be available for post-graduate students. Contact the listed researchers for details. CRC for Satellite Systems
Listed Researchers in ATMOZ-GPS
Probing the atmosphere and ionosphere using GPS Signals

Dr Elizabeth Essex
Space Physics Department
Faculty of Science, Technology and Engineering
La Trobe University
Melbourne, Australia 3083 Dr Essex is the research manager for GPS Signal Science within the CRC for Satellite Systems. She is directing a program that uses GPS signals, received a ground stations in Australia and Antarctica, to probe the geosphere. Experiments on-board FedSat 1 will study the occultation of GPS SV signals, probing all levels of the atmosphere.

Space based and Ground based Computerised Ionospheric Tomography
Mapping the Ionosphere in the Australian and Antarctic Region
See the text summary of her research projects.

Further info:

Ionosphere fact sheet.
Pix of Successful Challenger 1985 Mission Blast-off.

ATMOZ-GPS Project
Sounding the Atmosphere
using GPS Signals

The objective of the GPS/Occultation experiment is to use signals from GPS satellites almost occulted by the Earth. Such signals have a path an important component of which is through the lower atmosphere. GPS signals indicate to remarkable precision the instant of trasnmission, and we know with precision the location of the SV, and of the receiving satellite Using near-occultation data we will be able to take temperature, pressure, and other measurements at hundreds of points on the Earth every day, extending from near the surface up through the ionosphere. See Overview of GPS/MET University Corporation for Atmospheric Research.
FedSat is shown in low earth orbit about the earth, atmosphere and ionosphere indicated. In a larger orbit of 12 hours period are shown the 4 GPS SV's (Space Vehicles) that traverse the same orbit. The total GPS sysytem involves 24 SVs in 6 orbits inclined at 55 degrees to the equator. Just one of the 4 SVs is in (near) occultation, and the GPS signals received by FedSat have passed through the atmosphere and ionosphere.
Space Weather
Ionospheric Tomography
FedSat 1 will have a GPS antenna that can detect signals from (almost) vertically above. We know precisely when and where GPS signal packets started out from and where and when FedSat received them. By comparing GPS signals of different frequencies, we can infer, after a mammoth "tomographical reconstruction" just what is going on -- in real-time -- through the atmosphere.

Topex/Poseidon Experiments
The Topex/Poseidon satellite, a joint NASA/CNES Project uses radar to measure sea heights accurately, of special interest in global warming studies. The NASA altimeter on board Topex/Poseidon measures the difference in the delays of two radar pulses of different frequencies, (technically the Ku and C band pulses) Dr Essex and her research students use this difference in the time of the two pulses in the mapping of the ionosphere, especially over the expanses of the southern hemisphere oceans.

Black Hole Over Tasmania
Punching a hole in the Ionosphere
The fact that major rocket burns can punch a short-lived hole in the ionosphere was discovered by Michael Mendillo, of Boston University. Two holes in the ionosphere were deliberated punched in 1985 by firing the thrust rockets of the Space Shuttle Challenger over Tasmania and also over Boston. CRCSS key researcher Elizabeth Essex collaborated with Michael Mendillo in monitoring this historic experiment. Such a short-lived hole provides access on Earth to astronomical information normally hidden by the ionosphere.

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Post-graduate Projects in Satellite & Space
Science at La Trobe University CRC Satellite Systems Home Page

ATMOZ-GPS Project Sounding the Atmosphere using GPS Signals The objective of the GPS/Occultation experiment is to use signals from GPS satellites almost occulted by the Earth. Such signals have a path an important component of which is through the lower atmosphere. GPS signals indicate to remarkable precision the instant of trasnmission, and we know with precision the location of the SV, and of the receiving satellite Using near-occultation data we will be able to take temperature, pressure, and other measurements at hundreds of points on the Earth every day, extending from near the surface up through the ionosphere. See Overview of GPS/MET University Corporation for Atmospheric Research.	FedSat is shown in low earth orbit about the earth, atmosphere and ionosphere indicated. In a larger orbit of 12 hours period are shown the 4 GPS SV's (Space Vehicles) that traverse the same orbit. The total GPS sysytem involves 24 SVs in 6 orbits inclined at 55 degrees to the equator. Just one of the 4 SVs is in (near) occultation, and the GPS signals received by FedSat have passed through the atmosphere and ionosphere. Space Weather Ionospheric Tomography FedSat 1 will have a GPS antenna that can detect signals from (almost) vertically above. We know precisely when and where GPS signal packets started out from and where and when FedSat received them. By comparing GPS signals of different frequencies, we can infer, after a mammoth "tomographical reconstruction" just what is going on -- in real-time -- through the atmosphere.
	Topex/Poseidon Experiments The Topex/Poseidon satellite, a joint NASA/CNES Project uses radar to measure sea heights accurately, of special interest in global warming studies. The NASA altimeter on board Topex/Poseidon measures the difference in the delays of two radar pulses of different frequencies, (technically the Ku and C band pulses) Dr Essex and her research students use this difference in the time of the two pulses in the mapping of the ionosphere, especially over the expanses of the southern hemisphere oceans.
	Black Hole Over Tasmania Punching a hole in the Ionosphere The fact that major rocket burns can punch a short-lived hole in the ionosphere was discovered by Michael Mendillo, of Boston University. Two holes in the ionosphere were deliberated punched in 1985 by firing the thrust rockets of the Space Shuttle Challenger over Tasmania and also over Boston. CRCSS key researcher Elizabeth Essex collaborated with Michael Mendillo in monitoring this historic experiment. Such a short-lived hole provides access on Earth to astronomical information normally hidden by the ionosphere.