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1-30 Q31. What transmission method uses a stable cw reference oscillator, which is locked in phase with the transmitter frequency? RADAR CLASSIFICATION AND USE Radar systems, like cars, come in a variety of sizes and have different performance specifications. Some radar systems are used for air-traffic control at airports and others are used for long-range surveillance and early-warning systems. A radar system is the heart of a missile guidance system. Small portable radar systems that can be maintained and operated by one person are available as well as systems that occupy several large rooms. MILITARY CLASSIFICATION OF RADAR SYSTEMS The large number of radar systems used by the military has forced the development of a joint- services classification system for accurate identification. The Federal Aviation Agency (FAA) also makes extensive use of radar systems for commercial aircraft in-flight and landing control, but does not use the military classification system. Radar systems are usually classified according to specific function and installation vehicle. Some common examples are listed below: FUNCTION INSTALLATION VEHICLE Search Ground or land based Track Airborne Height-finder Shipboard The joint-service standardized classification system further divides these broad categories for more precise identification. Table 1-1 is a listing of equipment identification indicators. Use of the table to identify a particular radar system is illustrated in figure 1-23. Note that for simplicity, only a portion of the table has been used in the illustration.