12 Radar Target Classification Technologies

Apart from object detection, plot extraction and tracking, automatical classification is becoming one of the challenges of modern sensor systems. In civil applications for example, different classification techniques are used for air traffic control (ATC) purposes. The primary purposes of air traffic control systems are collision prevention, the organization and control of the air traffic; furthermore it should provide information as well as other support for pilots. In most cases the general traffic situation is well known (aircraft, flight number, flight road, flight departure and destination, etc.), but the exact prediction of natural processes (weather, bird migration, wind mill rotation activities, insect migration, etc.) still remains rather difficult. For this reason the demanded expectations are stable feature extraction methods and classification technologies. In meteorological applications, weather radars use backscattered echo signals to locate precipitation, calculate its motion, estimate its type (rain, snow, wind, hail, etc.) and forecast its future position and intensity. For this purpose modern weather radars are mostly pulseDoppler radars. These are able to detect the motion of rain droplets as well as to estimate the intensity of precipitation. The structure of storms and severe weather can be derived from these data. In order to improve the efficiency of new weather radar product families, strong feature extraction and classification algorithms are required. In the automotive industry, due to higher safety measure requirements in road traffic, the adaptive cruise control (ACC) is becoming unavoidable. These systems often use a radar setup to slow the vehicle down when approaching another vehicle or other obstacles and accelerate again to the present speed as soon as traffic allows it. ACC technology is widely considered as a key component for future generation's smart cars, as a form of artificial intelligence that can be used as a driving aid. For that reason robust signal feature extraction and classification methods are required. For airborne applications, two kind of radars can be integrated in air platforms, in order to support the navigation and missions. The first category encompasses primary radars, the second category secondary radars. Civil airborne primary radar systems support the pilot by providing actual information like position or weather. Civil secondary surveillance radars (SSR) are radar systems supporting air traffic control (ATC). These systems do not only detect and measure the position of aircraft but also request additional information from the aircraft itself such as its identity or altitude. While primary radar systems measure only the range and bearing of targets based on reflected radio signals, SSRs rely on radar transponders aboard aircrafts. These transponders reply to interrogation signals by