|
Monitoring and Analysis of Manufacturing Processes in Automotive |
ABSTRACT
The field of Frequency Modulated Continuous Wave (FMCW) radar represents a significant area of modern intelligent transportation systems. Owing to their ability to simultaneously determine the distance and relative velocity of objects through the exploitation of the Doppler effect, FMCW radars have found widespread application, particularly in automotive Advanced Driver Assistance Systems (ADAS) and autonomous driving technologies. Building upon these technological advances, the presented monograph extends their application to aviation by investigating the use of onboard FMCW radio altimeters as cost-effective terrain collision avoidance systems for small aircraft and helicopters. The monograph provides a comprehensive theoretical and experimental analysis of the Doppler component contained in the beat signal for predicting the time to terrain collision, experimentally validates the proposed concepts under real flight conditions, and introduces novel methods for improving measurement accuracy. The proposed solutions extend the functionality of existing radio altimeters by incorporating active Controlled Flight Into Terrain (CFIT) warning capabilities without the need for expensive onboard terrain awareness systems, thereby contributing significantly to the enhancement of flight safety.
KEYWORDS:
FMCW radio altimeter, Doppler effect, Terrain collision avoidance, Controlled Flight into Terrain (CFIT), Helicopter flight safety, Radio altimeter signal processing, Mathe-matical modelling, Terrain awareness, Low-altitude helicopter operations.
PREFACE:
The presented monograph aims to address the need for cost-effective terrain collision avoidance systems for small aircraft and helicopters. The rapid advancement of aviation technology and the increasing volume of air traffic have highlighted the necessity for affordable anti-collision systems for these aircraft, which are not required by current regulations to be equipped with complex systems such as TCAS/ACAS or EGPWS. Building upon the monograph Applied Technologies for the Use of FMCW Radio Altimeter, this work explores the possibilities of extending the functionality of onboard low-range frequency-modulated continuous wave (FMCW) radio altimeters to create simple terrain collision avoidance and warning systems. The monograph provides a comprehensive theoretical and experimental analysis of FMCW altimeter operation, with a special focus on utilizing the Doppler component in the difference frequency signal. Through mathematical modeling, error analysis, and stabilization of the altimeter constant, the authors demonstrate that the existing altimeter hardware can be effectively used not only for precise altitude measurement but also for predicting the time to potential collision with rising terrain. The monograph experimentally verifies the Doppler effect during flights over ascending terrain, presents dual-channel altimeter configurations, and introduces a patented measurement method using a depolarization plate, which significantly improves the resolution of methodological errors. It proposes supplementary solutions based on the research, which generate timely warnings of approaching terrain based on the ratio of altitude to vertical velocity, and integrates altimeter outputs with aircraft dynamic models to enhance the crew’s situational awareness. The proposed solutions offer a practical and economically accessible way to improve flight safety for small aircraft and helicopters, particularly in operations where expensive advanced systems are not available. They may also help reduce the risk of controlled flight into terrain (CFIT).