Using a rotating quarter-wave phase plate in polarization-modulation methods for determining the roll and bearing angles of an aircraft

A polarization-modulation method for simultaneous determination of the navigation parameters of the bearing and roll of an aircraft from orthogonally linearly polarized beacon signals is studied. Signals are emitted simultaneously from two spatially separated points in the horizontal plane with known coordinates. On Board the aircraft, the resulting vector signals are received by the onboard receiving antenna, in the path of which a polarizing modulator is installed. A rotating section of a circular waveguide with a quarter-wave phase plate embedded inside is used as a polarizing modulator. The bearing and roll of the aircraft are estimated at the output of a single-channel receiver, respectively, by the amplitudes and phases of the second and fourth harmonics of the polarization modulation frequency contained in the envelope spectrum of the received resulting vector signals.

Vector signal analysis and synthesis solutions overview

Modern signals with a complex structure require technological equipment capable of evaluating many parameters that determine the signal quality. Therefore, in order to systematize the solutions existing on the market and their capabilities, a review was made of the solutions existing on the market for the synthesis and analysis of complex signals. The main parameters for assessing the quality of complex signals are considered, the characteristics of generators and analyzers of complex signals existing on the market are presented and their comparison is made according to the main consumer qualities. The article also describes the basic principles of generation and analysis of vector signals. The direction of increasing the significance of the software complex in systems for generating and analyzing signals and the advantages determined by this trend, such as an increase in the time of possible operation of equipment and an increase in versatility, which makes it possible to increase the economic efficiency of the used control and measuring equipment, are shown.

MODEL OF A MATRIX CROSSCORRELATION FUNCTION OF THE PROBING AND REFLECTED VECTOR SIGNALS FOR A CONCEPTUAL DESIGN OF A SYNTHETIC APERTURE RADAR ON AN AERIAL CARRIER

In order to simulate the process of design development in full on computer models, including virtual tests of the synthetic aperture radar on an air carrier in model media, the study develops a structural scheme of the conceptual design of the synthetic aperture radar on an air carrier. The scheme is invariant with respect to the type of an air carrier with a synthetic aperture radar: an aircraft, a helicopter, an unmanned aerial vehicle and similar ones: an air carrier "enters" it by only an automatic control system, a model of trajectory instabilities and a spectrum of frequencies of elastic oscillations of its design. To perform a computer simulation of radar systems with full polarization sensing, a model of a matrix cross-correlation function of probing and reflected vector signals is proposed. As a model of the scattering object, a set of independent point reflectors distributed over space and generally having different rates of motion is accepted. The reflected signal is a sum of elementary signals, their form completely repeats the shape of the emitted signal, and the amplitude, the phase and polarization are respectively determined by the coordinate, velocity and polarization parameters of elementary reflectors forming a spatially extended object. Taking into account the developed models for the formation of the vector sounding signal and the matrix response function of the distributed radar object, a block-diagram of the model of the matrix cross-correlation function of the emitted and reflected vector signals is proposed. A block-diagram is the basis for the development of an algorithm and a program for computer modeling of the primary signal processing in a radar station with full polarization sensing.

Vector reconstruction of multicomponent seismic data

A multicomponent seismic record was transformed to the frequency-wavenumber domain using the quaternion Fourier transform. This transform was integrated into the projection onto convex sets algorithm to allow for the reconstruction of vector signals. The method took advantage of the spectral overlap of components in the frequency-wavenumber domain. The results of the method were compared with standard component-by-component reconstruction. Results were found for synthetic and real data including an example of 5D reconstruction of a converted-wave data set acquired over a heavy oil reservoir. We found an improvement in reconstruction quality producing fully sampled radial and transverse offset-azimuth gathers with a preserved vector relationship.