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Monash Suominet Site

Investigators

Dr. Jason Beringer (School of Geography and Environmental Science, Monash University) in a cooperative agreement with UNAVCO (USA) and the Land Information Group of Land Victoria, Department of Natural Resources and Environment.

Project Overview

SuomiNet is an international network of GPS receivers, configured and managed to generate near real-time estimates of precipitable water vapor in the atmosphere, total electron content in the ionosphere, and other meteorological and geodetic information. Realtime readings from the weather station along with a weathercam are available.

The Monash site consists of a dual frequency GPS receiver and an array of meteorological instruments mounted together with a traditional trig beacon for use by land surveyors. The GPS signals will be analysed together with meteorological data to determine the precipitable water vapour content assisting in weather predication. The same GPS data will be used in Victoria's co-operative GPS base station network called GPSnet to assist spatial data scientists determine accurate positions on the earth's surface.

The Site

The Monash site is located at GDA Latitude: 37 54 45.2552 South, Longitude: 145 07 57.8833 East, 147.8 m Ellipsoidal Height and is the only site currently located in Australia.

Data

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Click here for current weeks data.

GPSnet GPS Base Station Network

GPSnet is a VICTORIAN network of co-operative GPS base stations located across the state. The network records, distributes and archives GPS satellite correction data for accurate position determination by post processing techniques, 24 hours a day statewide. The GPSnet is operated by Lands Victoria. The School of Geography and Environmental Science through the Suominet station now contributes to the GPSnet. High quality geodetic information can be obtained through the GPSnet. The base stations can support centimetre accurate positioning service over the entire state when the network is complete.

Each GPSnet site consists of a dual frequency GPS receiver, capable of receiving both code and carrier phase on L1 and L2. The sites are installed with a geodetic quality antenna, which commonly consists of a ground plane and choke ring to minimise the effects of multi path. All antenna locations are tied into the Australian National Network which in turn is a subsidiary of the Australian Fiducial Network to a high degree of accuracy.

How it works

The following information is taken from the Bulletin of the American Meteorological Society article Click here for a PDF copy

Summary

SuomiNet, a university-based, real-time, national Global Positioning System (GPS) network, is being developed for atmospheric research and education with funding from the National Science Foundation and with cost share from collaborating universities. The network, named to honor meteorological satellite pioneer Verner Suomi, will exploit the recently shown ability of ground-based GPS receivers to make thousands of accurate upper- and lower-atmospheric measurements per day. Phase delays induced in GPS signals by the ionosphere and neutral atmosphere can be measured with high precision simultaneously along a dozen or so GPS ray paths in the field of view. These delays can be converted into integrated water vapor (if surface pressure data or estimates are available) and total electron content (TEC), along each GPS ray path. The resulting continuous, accurate, all-weather, real-time GPS moisture data will help advance university research in mesoscale modeling and data assimilation, severe weather, precipitation, cloud dynamics, regional climate, and hydrology. Similarly, continuous, accurate, all-weather, real-time TEC data have applications in modeling and prediction of severe terrestrial and space weather, detection and forecasting of low-altitude ionospheric scintillation activity and geomagnetic storm effects at ionospheric midlatitudes, and detection of ionospheric effects induced by a variety of geophysical events. SuomiNet data also have potential applications in coastal meteorology, providing ground truth for satellite radiometry, and detection of scintillation associated with atmospheric turbulence in the lower troposphere. The goal of SuomiNet is to make large amounts of spatially and temporally dense GPS-sensed atmospheric data widely available in real time, for academic research and education.

Research applications

The atmosphere is illuminated with 1.6- and 1.2-GHz (L1 and L2) signals transmitted by the 24 Global Positioning System (GPS) satellites. Phases of signals from a dozen or so of these satellites can be simultaneously observed with millimeter precision during all weather conditions, using commercial GPS receivers. Observing from sea level, the lower and upper atmosphere induce GPS signal phase path delays of several meters or more. The key to SuomiNet-enabled research (and education) is to view these delays not as signal propagation errors but as atmospheric information. In the upper atmosphere, Total Electron Content (TEC) along each GPS ray path can be measured by combining L1 and L2 phase observations.

In the lower atmosphere, dry air, water vapor, and hydrometeors induce delays in GPS signals. However, effects generated by hydrometeors are relatively small. As a result, water vapor, integrated along each GPS signal path, can be inferred if observed or estimated surface pressure is available. Accurate geodetic coordinates also can be derived from these data, as has been amply demonstrated (Stein et al. 1998).

The Installation