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罗兰是英文远距离导航的缩写,是一种双曲线无线电定位系统。1940年由美国提出的叫罗兰-A,它包括一个主控站和多个从属站,工作频率在1800到2000kHz的范围内。罗兰-A在海面上用地面波可传播600到800nmile。在夜间用空间波可使传播距离增大到1500nmile。地面波的定位精度在1到2nmile之间,而空间波的定位精度依据条件而不同,在7到40nmile之间。到七十年代,罗兰-A的应用达到了顶峰,只是由于两个原因,未被推广到地面车辆上应用。一是它到八十年代将被淘汰,另一是罗兰-C比罗兰-A更优越。尽管如此,由于某些问
Roland is an abbreviation for English long-distance navigation, is a hyperbolic radio positioning system. Proposed by the United States in 1940 called Roland-A, which includes a master station and multiple slave stations, operating frequency range of 1800 to 2000kHz. Roland-A on the ground with ground waves can spread 600 to 800nmile. In the night space wave can increase the propagation distance to 1500nmile. The accuracy of the ground wave positioning between 1nm2nmile, and the spatial wave positioning accuracy based on different conditions, between 7nm to 40nmile. By the 1970s, the Roland-A had reached its peak of application, only for two reasons, not being applied to ground vehicles. First, it will be eliminated in the eighties, the other is Roland-C better than Roland-A. However, due to some questions