Aerospace Platforms Research Articles

Bistatic radar without transmitted signal-covert altimetry concept

A technique for performing altimetric functions (and possibly very-low-resolution imaging radar) without the transmission of a signal is suggested. The system could benefit an invasive aerospace platform that needs to remain totally electronically silent. The concept uses naturally occurring galactic noise as the illumination signal. A rapid and low-cost processor is also suggested. The results developed are also useful for the particular case of low probability of intercept (LPI) radar in which the transmitter emits a broadband Gaussian-like signal and the receivers cannot locally generate the transmitted reference. Another derivation of the arcsine law is provided along with a measure of its efficiency compared with an optimal receiver.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Remote sensing surveys design in regional agricultural inventories

In this paper, we consider the methodology problems of remote sensing surveys design in regional agricultural inventories. The strategy of samples, based on the combined use of multispectral aerospace data and ground truth data obtained on test sites in the region under supervision, is used. The strategy of samples includes: selection of areas, which are statistically homogenous with certain agricultural parameters under research, identification of representative test sites grid; remote sensing from aerospace platforms and ground truth data acquisition on test sites as well. The ground measurements of biometrical parameters of certain agricultural crops under research are taken at test sites, maps of anomalies are compiled, spectrometrical and other optico-physical characteristics of vegetation canopies and soils are defined. The derived data are used in automatic interactive imagery processing at the training stages of the procedures of classification and application of thematical remote sensing data processing results to the entire region.

Some features of radar monitoring of the oceanic surface from aerospace platforms

Abstract Specifics of oceanic surface remote sensing are studied when the wave pattern is inhomogeneous due to slicks caused by streams, oil films, etc. A model of radar signals scattered by inhomogeneous waves is suggested, based on observations carried out. Statistical characteristics of the response signal are studied. Effect of resolution on reflection contrasts is discussed.

Information processing of remotely sensed agricultural data

Systems utilizing sensors on aerospace platforms for the purpose of surveying earth resources have been under study recently. In this paper research on the information processing portion of such a system for agricultural resources is described. In particular the application of pattern recognition techniques to muItispectral data is proposed and example results are presented. Good classification accuracy on crop species identification of some 40 000 samples in a five square mile area was achieved in one example. Other examples show results in feature selection and nonparametric classifier algorithms.