The problem of detecting low-signal-level echoes is very important for the safety of navigation. The article presents methods for detecting such echoes. These methods are based on the processing and analysis of the raw video signal in a navigation radar.1. INTRODUCTION
The process of navigation based on onboard radar systems (radar navigation) is still characterized by relatively low accuracy. The reasons for this are not only radio wave interference (at the radar operating frequency) that is difficult to eliminate and technical limitations in the presentation of radar echoes on the screen, but also incorrect identification of radar echoes and random and deterministic interference of radar observation.
Navigation radars, although continuously improved, are not perfect. Their disadvantage is low resistance to interference, including passive interference, and insufficient sensitivity, which hinders or sometimes even makes it impossible to detect small objects. Introducing modern technologies as well as new software analyzing the radar video signal can significantly improve the echo detection process, and thus increase the probability of detecting useful echoes, including echoes located in areas of interference.
In maritime navigation, the radar is the primary device used by the navigator to avoid collisions with other objects present in the water area. Modern radar technology has now reached a level that allows for the construction of modern, high-sensitivity radars capable of detecting both large objects with a large reflective surface and, equally importantly, small objects generating weak radar echoes. A major problem with such devices, however, is distinguishing what constitutes a real radar echo from the noise present in the signal received from the antenna. The signal level for small objects generating weak echoes is simply very often at the same level as the aforementioned noise. In currently used navigation radars, weak echoes are eliminated from the radar image due to their difficulty in being distinguished from noise. (…)
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Source: Logistyka Magazine
Detection of low-amplitude radar echoes safety radar navigation detection – PDF file for download