RBN造句

Some 17 traffic-control systems have been established, 300 navigation aids set up or upgraded, and 20 RBN-DGPS stations in coastal ports and crucial waters established, basically achieving the target for completing the nation's navigation aid chains.

索引文件中最低一级的索引块,其内容包括相对块号(RBN)和几个数据块的高一级的关键字。