Performance Analysis of Navigation Signal Based on FH-BOC Modulation System

Based on the traditional BOC modulation system, a new navigation signal system based on FH-BOC is proposed in this paper. The simulation and verification of FH-BOC signal are carried out, and the modulation characteristics, code tracking performance and anti-interference performance of FH-BOC signal are analyzed, and the advantages and disadvantages of the modified system are verified. The results show that FH-BOC signal has good ranging and anti-interference ability, which is suitable for navigation system and can reduce the ambiguity of BOC signal’s secondary peak to a certain extent. At the same time, the T has important scientific significance and application value to improve the countermeasure capability of other satellite navigation systems.

SIMULATION OF EGNOS SATELLITE NAVIGATION SIGNAL USAGE FOR AIRCRAFT LPV PRECISION INSTRUMENT APPROACH

Satellite navigation has become a very important topic in the air transport industry along with its application in instrument approach procedures. Recently, extracted statistical characteristics of the European Geostationary Navigation Overlay Service (EGNOS) satellite signal have been made available from real measurements in the Czech Republic. The numerical modeling approach is taken for a feasibility study of automatic aircraft control during the Localizer Performance with Vertical Guidance (LPV) precision approach based on such navigation data. The model incorporates Kalman filtering of the stochastic navigation signal, feed-back control of L-410 aircraft dynamics and the calculation of approach progress along the predefined procedure. Evaluation of the performance of the system prototype is performed using the scenarios developed with a strong interest in altitude control. The specific scenario is focused on a curved approach which offers a huge advantage of the approaches based on the Satellite-based Augmentation System (SBAS) compared to ones with the Instrument Landing System (ILS). Outputs of simulation executions are statistically analyzed and assessed against predefined navigation performance goals equivalent to ILS categories with a positive outcome.

DETERMINATION OF CHARACTERISTICS OF UNDERWATER AUTONOMOUS APPARATUS TRANSITORY TO THE DOCKING MODULE FOR HNS WITH ULTRASHORT BASE

The expediency of creation of the apparatus of the high-frequency hydroacoustic system of transformation in the form of the jointed information and navigation system combined on base of antennas of system in which hydroacoustic navigation systems with ultrashort base can be used is reasonable; it is offered to use signals of data which the docking module and autonomous underwater apparatus exchange by results of measurement of mutual navigation characteristics as navigation. In a point of reception signals are observed reflected from a bottom and surface in the presence of reflecting surfaces which can be with a small depth of water area compared to horizontal distance to SA. The sizes of the reflected signals will depend on effective areas ground and superficial scatterings, which depend on a mutual positioning of DM and SA at the depth of the water area. The spatial correlation of scattered signals renders the greatest influence in the mutual correlation processing of signals from the elements of antenna of HNS. The coefficient of correlation scattered component will be so small that it will give practically no displacement of the bearing estimate at the wave size of the antenna of HNS about 10l. At the small wave sizes of the antenna (commensurable with l) the coefficient of spatial correlation of hindrance can render noticeable influence on the estimate of a difference of phases of a navigation signal from exits of elements of the antenna of HNS. This influence affects especially strongly at estimate of corner of place. The size of the displacement of the estimate will be proportional to the size of the signal reflected from the surface of the water area and coefficient of its spatial correlation. When approaching the SA to the DM, there can be re-reflections of a navigation signal from elements of their constructions. At the radius of a nasal part of SA 0,2 meters the relation of levels will make about 30 dB. Displacement of estimate of difference of phases of signals will be only when there is an angular displacement at reflections (there is not symmetry at a reflection). However, even then influence of the re-reflected signal is small. Considering that the header of the information signal has the same volume of uncorrelated selection as an information signal we receive the relation a signal/hindrance at the input of the decisive scheme, equal 240, that exceeds necessary value for the set accuracy of definition of navigation characteristics.