Method for detecting curvilinear trajectories of air targets using parametric transformations

For effective detection of maneuvering targets in conditions of low values of the signal-to-noise ratio, block methods of trajectory processing based on parametric transformations are used. The use of parametric transformations increases the resistance of the trajectory detection algorithm to an increase in the number of false marks and the omission of true ones in the analyzed sample, but is limited by the choice of a certain type of target movement model. The purpose of the article is to expand the possibilities for detecting target trajectories using parametric transformations by developing a new technique that solves the problem of detecting trajectories of air targets moving with lateral accelerations or maneuvering simultaneously in two planes. The paper proposes a method for restoring curvilinear trajectories of air objects (in the form of an ellipse) using the parametric Radon transform. The structure of the methodology is presented in the form of successive stages: formation of a sample of true and false marks for n surveys, parametric conversion of marks, clustering of selected groups, inter-survey identification of marks and making a decision on target detection and its trajectory. A variant of the parametric transformation for the selection of ellipses with various parameters and criteria for choosing the optimal values of the parameters that affect the operation of the technique are proposed. Estimates of the quality of the method are obtained based on the results of a statistical experiment, confirming the high capabilities of detecting target trajectories.

Green-Yellow-Orange-Red Spectral Range with Sum-Frequency Generation Using BIBO Crystal Pumped with an Optical Parametric Amplifier

In this letter, we show the broadband sum-frequency generation (SFG) in the Green-Yellow-Orange-Red spectral range using bismuth triborate, BiB3O6 crystal (BIBO) as a nonlinear material. We perform a noncollinear phase-matching configuration within the BIBO crystal using the remaining light behind the second harmonic generation stage and the infrared idler of an optical parametric amplifier (OPA). The obtained mixing radiation of ultrafast light sources to generate femtosecond pulses across the 520.5 to 742.5 nm region is observed. The SFG spectrum from a single-pass cross-correlation intensity over such visible range is shown. The SFG wavelengths as a function of the tunable wavelength idler OPA agree with the expectations of the parametric conversion condition and open the door to practical multi-beam or multi-color sum-frequency generators.

Green-Yellow-Orange-Red Spectral Range with Sum-frequency Generation Using BIBO Crystal Pumped with an Optical Parametric Amplifier

We show broadband sum-frequency generation (SFG) in the Green-Yellow-Orange-Red spectral range using bismuth triborate, BiB3O6 crystal (BIBO) as nonlinear material. We perform a noncollinear phase-matching configuration within BIBO crystal using the remaining light behind the second harmonic generation stage and the infrared idler of an optical parametric amplifier (OPA). The obtained mixing radiation of ultrafast light sources to generate femtosecond pulses across 520.5 to 742.5 nm region is observed. SFG spectrum from single-pass cross-correlation intensity over such visible range is showed. The SFG wavelengths as a function of tunable wavelength idler OPA agrees with the expectations of parametric conversion condition and open the door to practical multi-beam or multi-color sum-frequency generators.