中文摘要：

卫星通信以其独特的特点,在许多场合中具有重要的应用价值。在指挥调度、应急救灾等场合中一般使用地面集群通信,但是其信号覆盖范围有限,集群通信组网受频率资源限制比较大。将具有覆盖面积大、受地理条件限制小以及通信频带宽等特点的卫星通信系统与地面集群通信系统结合组网,形成天地一体化的通信网络。

英文摘要：

Satellite communication with its unqiue characteristics has a great practical application value in various fields.Ground trunking communication is often used in areas such as command,control and emergency services,etc.However,because of its limited signal scope,the trunking communication network is limited greatly by frequency resource.The satellite communication system,with its characteristics of large coverage area,few restriction by geography and wide communication frequency band,is integrated with ground trunking communication system to form an air-to-ground communication network.