Agilent Secondary Radar Transponder Testing Using the 8990B Peak Power Analyzer - Application Note 5991-1192 free download

File name Secondary Radar Transponder Testing Using the 8990B Peak Power Analyzer - Application Note 5991-1192

Secondary Radar Transponder Testing Using the 8990B Peak Power Analyzer Application Note Introduction After a brief review of radar systems and the role of transponders, this applica- tion note provides examples of how to effectively test transponders in order to validate their performance and function. Testing is performed using a transpon- der test set and an Agilent peak performance analyzer (PPA). The measurement examples provided cover interrogation and reply transmit power and pulse profiling, double pulse spacing, and reply delay timing measurement. Secondary Radar Secondary radar originated from the identification friend or foe (IFF) radar signal system used during World War II and complements the limitations of primary Background radar systems. Primary radar works by passively reflecting a radar signal off of the target's reflection or surfaces (called echoes). A limitation of primary radar is that it has difficulty detecting non-metal or composite-based aircraft parts. Another weak- ness is weather-related. In heavy rain, reflected signals are prone to attenuation, decreasing detection accuracy. Secondary radar works by transmitting and receiving high-frequency modulated pulses, also called interrogation and reply signals. Figure 1 illustrates the operat- ing principle of secondary radar systems. It begins when the ground station sends interrogation signals to the airborne aircraft. The plane's on board tran- sponder responds to the interrogation signals by transmitting back reply signals. Modern secondary radar systems are used in both civilian and military aviation operations. The civilian's secondary radar system is called secondary surveil- lance radar (SSR) and it is primarily used for air traffic control such as in the Air Traffic Control Radar Beacon System (ATCRBS) and the Traffic Collision Avoidance System (TCAS). SSR operates in different modes known by letter designators such as Modes A, B, C, D, and S. Rather th