1, Automatic Directional Machine (ADF), also known as radio compass, realizes the navigation and guidance of aircraft by receiving signals from civil medium-wave radio stations or NDB special ground navigation stations.
2. VHF omni-directional beacon system
VOR, like the integrated ADF, belongs to other standby navigation and radio angle measurement systems. They are all composed of airborne receivers and ground stations. Because the working frequency of VOR system is in VHF band, its measurement accuracy and stability are better than those of medium-wave and long-wave ADF.
3. Instrument landing system
It can provide guidance information to pilots in bad weather conditions and poor visibility to ensure the safe approach and landing of aircraft, so it is also called blind landing system.
4. Traffic Advisory and Collision Avoidance System (TACS)
By transmitting radio frequency signals, it interrogates aircraft flying in the same airspace with TCAS or ATC transponder, and continuously monitors and evaluates whether these aircraft pose a threat to aircraft. If there is a potential collision threat, it will issue different levels of suggestions and warnings according to the situation, and the pilot can take necessary actions according to these suggestions and warning information to avoid air collision.
Extended data:
Radar is an electronic device that uses electromagnetic waves to detect targets, that is, by radio to find targets and determine their spatial positions. Therefore, radar is also called "radio positioning". Radar is an electronic device that uses electromagnetic waves to detect targets.
The radar emits electromagnetic waves to illuminate the target and receives its echoes, thus obtaining information such as the distance from the target to the electromagnetic wave emission point, the rate of change of distance (radial speed), azimuth, altitude and so on.
The function of radar is similar to eyes and ears, and its information carrier is radio waves. In fact, visible light and radio waves are essentially the same thing, both electromagnetic waves, and the propagation speed in vacuum is the speed of light C, the difference lies in their respective frequencies and wavelengths.
References:
Baidu encyclopedia-airplane