A radio navigation system is a navigation technique that reaches a destination at a specified time. The navigation parameters (azimuth, distance and speed) of the aircraft can be measured using the propagation characteristics of the radio waves, and the deviation from the specified route is calculated. Radio Guide System The operator or the autopilot manipulates the vehicle to eliminate the deviation to maintain the correct route.
The radionavigation system utilizes the basic principle of radio wave propagation: the radio signal is propagated in the free Radio Guide System space in a straight line at the speed of light. As long as the propagation time of the radio wave from the transmitter to the receiver is determined, it is possible to determine the distance between the transceivers The distance is the product of the speed of light and the time of propagation. Typically, the navigation should be done by the navigation system, including the navigation device mounted on the carrier and the navigation station used in conjunction with the navigation device. Where the navigation between the mobile station and the mobile carrier for the media to achieve navigation, known as radio navigation.
From the location of the navigation station to determine the nature of navigation, mainly land-based navigation systems and satellite-based navigation system.
Land-based navigation systems are located on land, and between navigational platforms and navigation devices, such as VHF Radio Guide System omnidirectional beacons (VOR), microwave landing systems, Roland, Omega navigation systems.
Star-based navigation system navigation set in the satellite, the coverage greatly expanded, such as the United States GPS (Global Positioning System) and Russia's GLONASS satellite navigation system.
Radio navigation systems or systems used are radio compass, Volt navigation systems, Tacon navigation systems, Roland C navigation systems, Omega navigation systems, Doppler navigation systems, satellite navigation systems and the development of the "navigation star" Global positioning system.
The radio signal contains four electrical parameters: amplitude, frequency, time and phase. During the propagation of a radio wave, Radio Guide System a parameter may have a change related to a navigation parameter. By measuring this electrical parameter, the corresponding navigation parameters can be obtained. According to the measured electrical parameters, the radio navigation system can be divided into amplitude, frequency, time (pulse) and phase 4. The radionavigation system can also be divided into angle (azimuth or high and low angle), ranging, ranging and speed 4 according to the navigation parameters to be measured. Modern is also based on the main installation base of radio navigation equipment is divided into the foundation (the equipment is mainly installed on the ground or sea), the space base (the equipment is mainly installed on the flight of the aircraft) and the satellite base (equipment is mainly installed on the navigation satellite) 3 kinds. According to the role of distance is divided into short-range, remote, ultra-long and global positioning 4. Most of this system is working with the Doppler effect. A Doppler navigation radar mounted on an airplane transmits a radio signal in a centimeter band with a narrow beam to the ground. Due to the existence of the Doppler effect, the aircraft receives a signal Radio Guide System frequency reflected from the ground and the transmitted signal frequency is different, there is a Doppler shift, measured Doppler frequency shift can be obtained relative to the ground speed of the aircraft (see Doppler navigation system). And then use the vertical reference and heading on the aircraft to give the pitch angle and heading angle, the radial velocity decomposition of the east to the speed and north speed, respectively, for the time to find the location of the aircraft at the time. The position line of the Doppler velocimetry system is also a hyperbolic curve, which is made by Radio Guide System the Doppler shift cone and the height of the plane where the plane is located. Doppler navigation speed system is frequency (see aircraft navigation system).
The radio navigation system uses a radio transmitter (beacon) to draw a radio wave in the sky to draw a route, the aircraft according to these radio signals can be accurately on the flight, the aircraft began the instrument flight era. Radio navigation equipment has evolved over the last few decades. China is currently using two main categories. A class called non-directional beacon, also known as the wave of navigation stations, the English abbreviation for the NDB; the other is the VHF omnidirectional beacon (abbreviated as VOR) and range finder (abbreviated as DME) system. In the mid-wave navigation system, the aircraft uses a ring antenna that can be rotated to receive the signal. When the strongest direction of the radio wave is measured, the antenna stops rotating, and the azimuth between the radio and the airplane is measured. The plane is flying in this direction and can fly to the position where the radio is located. The accuracy of the wave navigator is low and is susceptible to weather, but it is cheap and equipment is durable, so many of the world's small and medium-sized airports and most of the developing countries are still using it. China's vast western region of the airport is also using this system. |
