Convener:
Frank D. Lind, MIT Haystack Observatory, (flind@haystack.mit.edu)
2004 Tuesday 29 June 0100-0300 PM
This workshop focused on current and future efforts to deploy and use radio and radar instrumentation networks for CEDAR related science. The purpose of the workshop was to provide a forum for discussing current efforts and insights in this regard. The workshop was attended by approximately 50 people. The first hour of the workshop was taken up by a series of four invited talks. The remaining hour was dedicated to more open discussions.
The first speaker was John Foster of MIT who discussed DASI : Distributed Arrays of Small Instruments. DASI is currently a project under development to enable the deployment of a wide range of instrumentation to provide wide spatial coverage of geospace using ground based sensor networks. This would happen through a Major Research Equipment (MRE) proposal to NSF at some point in the future. John reported on the intent of DASI as well as a recent (June 2004) NRC workshop in Wood's Hole, MA where the science rationale of DASI was discussed. DASI will need from the start to be a community effort but there is great enthusiasm for the science potential particularly when these types of instruments are combined with assimilative modeling. John gave examples of the power of distributed arrays of small instruments using GPS TEC mapping examples for observations of Storm Enhanced Density regions of the American sector.
The second speaker was Ray Greenwald of JHU/APL who discussed the SuperDARN network. Ray provided an overview of the the current SuperDARN deployment and planned expansions both in the north and southern hemispheres. Of particular note were efforts to provide new SuperDARN radar systems at mid-latitudes which will provide coverage during geomagnetic events. Ray provided an extensive discussion of logistical issues associated with SuperDARN as well as the role of international collaborations in fielding a distributed radar system. Ray placed emphasis on the need to have uniform data standards and a formalized means of gathering and distributing data.
The third speaker was Brent Ledvina of Cornell University who discussed software radio GPS receivers. Brent described the efforts at Cornell to develop implementations of GPS receivers where the primary signal processing is all performed on general purpose computers. This enables easy reconfiguration of the receivers as new navigation signals become available (e.g. GPS L5, Galileo, etc.) and allows customization of the receiver to observation tasks such as high rate scintillation monitoring. Brent discussed the advantages of software radios the primary of which are their performance, flexibility, and lower cost. He also showed examples from his current software radio implementation for L1 GPS signals and discussed performance constraints.
The fourth speaker was Frank Lind of MIT who discussed the Intercepted Signals for Ionospheric Science (ISIS) array. The ISIS Array is a distributed instrument project which has received $500k USD in hardware funding from the DoD Defense University Instrumentation (DURIP) program. The ISIS project is a prototype coherent software radio network capable of operating as a flexible multi-role distributed radio science instrument. In particular operational modes involving active and passive multistatic radar imaging, satellite beacon observation of TEC and scintillation, and radio intercept and TDOA applications will be supported over a wide range of operating frequencies (0.5 to 2000 MHz). The system will be constructed of a series of MIDAS-Mobile nodes (Millstone Data Acquisition System) which can coherently capture wide bandwidths of RF signals from a variety of antennas. The array will be capable of applying high performance supercomputing to the real time and batch processing requirements of a variety of experiments. Initial Deployment of the ISIS Array is expected to happen in summer 2005 with five nodes in the Northeast U.S. and two nodes in the Northwest.
Additional questions and discussions followed the main presentations and there was considerable enthusiasm for the above topics. After the main presentations the open discussion section of the workshop allowed short presentations by other interested parties. Bill Wright of NOAA discussed progress on the development of a new Dynasonde design using digital receivers and software radio approaches. Some discussion also occurred on the role of distributed instruments in supporting AMISR. In particular the logistical challenges were discussed along with the potential utility of orienting AMISR to take advantage of the expanded observational capabilities currently being deployed in Canada. At the end of the workshop the audience and participants were asked if this type of workshop should be organized again next year. It was clearly indicated that additional workshops on this topic should be organized in the future at CEDAR and other meetings.