UCAR-STARS: an altenative method for measuring characteristics of scatterers by spaced receiver remote sensors

The UCAR-STARS method is based on the calculation and analysis of auto- and cross-structure functions of different order for the received signals from spaced receivers. The mean speed components, turbulent parameters, shape, material, and other characteristics of scatterers can be estimated through application of UCAR-STARS to single-polarization spaced-receiver signals. The abbreviation UCAR-STARS stands for "University Corporation for Atmospheric Research - STructure function Analysis of Received Signals".

In the context of this work, the term "spaced receivers" means receivers providing signals from overlapping sample volumes. The results are not constrained to any one practical way for obtaining these signals. In particular, UCAR-STARS does not necessarily imply the use of several spaced antennas. In some cases a single antenna can be used to produce several signals from overlapping sample volumes.

Although the theoretical basis for the UCAR-STARS is universal, its application to practical measurements depends on the configuration and parameters of a remote sensor. There are theoretical limitations to the practical application of the UCAR-STARS that restrict its application to some types and configurations of remote sensors. These limitations follow from the three conditions necessary for UCAR-STARS application. These conditions are: at least three sequential samples for each one of received signals must be correlated; any pair of spaced received signals must be correlated for at least two sequential samples; temporal or spatial/temporal averaging must be accomplished in such a way as to ensure statistical convergence of estimates for the structure functions. Specific formulation of these conditions is presented and discussed.

It is demostrated that UCAR-STARS: does not induce radial velocity folding like Doppler velocity technique; is able to provide measurements at high temporal and spatial resolution; has low sensitivity to ground clutter and hard targets; effectively increases the signal-to-noise ratio for spaced antenna remote sensors by using significantly overlapping antennas; can lead to simplification of existing hardware by eliminating the need for the quadrature-phase synchronous detector, although it is completely applicable to standard complex output signals.

An application of the UCAR-STARS to the NCAR Multiple Antenna Profiler (MAPR) for measuring the mean horizontal wind speed components and turbulence intensity with high temporal and spatial resolution is demonstrated, and comparison of the MAPR results with those from a sonic anemometer is presented.

It is shown that UCAR-STARS supplements existing methods for measuring characteristics of scatterers by remote sensors without contradiction to existing methods.