Radar images are often characterized by speckle, which appears as a salt and pepper pattern.

Speckle can be reduced by application of appropriate digital filtering or multi look processing procedures.

Differential interferometry also allows for the monitoring of volcanic eruptions and earthquakes.

A satellite for very long baseline interferometry from space, called MUSES B, will be launched by ISAS in 1996.

Radar interferometry can also contribute to the understanding of earthquakes, especially in poorly equipped areas because it does not require ground instrumentation.

The reduction of speckle is a necessary precursor to computer classification of radar imagery as well as to visual interpretation since it tends to mask fine details.

However, the built in design margins of ERS 1 permit its operational use in the field of interferometry, for which it was not initially designed.

Recently, a new technique using synthetic aperture radar (SAR) satellite data, called radar interferometry, has been introduced in the analysis of vertical displacement associated with fault movements.

23. The technique of interferometry, by which the quot phase quot difference associated with a given pixel from two SAR images is analysed, allows for precise determination of elevation.

The Norwegian Defence Research Establishment (FFI) is actively contributing to the International Earth Rotation Service through analysis of global positioning system (GPS) and very long baseline interferometry (VLBI) measurements.

The International Radioastronomical Centre of Ventspils University College is participating in two projects within the Sixth Framework Programme the European radio astronomy programme RadioNet and Express Production Real Time electronic Very Long Baseline Interferometry Service.

The dense spatial samplings (100 pixels sq km) provided by radar interferometry in the detection of displacements associated with its accuracy (in the range of 3 10 mm) make it an important tool for assessing most natural hazards.