Drones are playing an increasingly important role in modern society. In military applications, the functions of drones are becoming increasingly complex, and a single drone is no longer able to meet the needs of complex tasks. Multiple unmanned aircraft with different characteristics and functions collaborating to carry out daily tasks such as artillery, surveillance, and multi-target attacks will be a key military operation method for unmanned aircraft in informationized warfare. Moreover, its application in specific fields is also quite different from before. Compared to many manned aircraft, unmanned aircraft have many advantages such as simple structure, low engineering cost, and no need for traditional aviators. In areas with high-risk factors (such as microbial, organic chemistry, and even nuclear environments), they are even better than many manned aircraft.

With the development trend of unmanned aircraft in various application fields, in some complex environments, the use of single-machine versions alone is no longer appropriate. It is necessary to form groups and collaborate to carry out relatively complex daily tasks. This requires that the unmanned aircraft system change from the current single-flight single-control mode to multi-flight single-control or multi-flight multi-control mode, and form an unmanned aircraft self-organizing network [1-2]. This network must be a highly cross-linked network. The topology structure of the Internet is rapidly changing, and there will be continuous addition or removal of connection points from the Internet. The wireless network self-organizing Internet (commonly known as Ad Hoc Internet) is a technical solution suitable for creating an unmanned aircraft Internet.

1. The principle and characteristics of unmanned aerial vehicle ad hoc networks

The unmanned aircraft self-organizing network is also known as the unmanned aircraft internet. It is a dynamic self-organizing application system composed of unmanned aircraft as network nodes, featuring randomness, temporariness and autonomy in its network topology.

Wireless networks enable communication at any time and anywhere. One of the Internet technologies is "the short-term interconnection of mobile nodes without any infrastructure", and it allows for the continuous establishment of mobile connectivity.

In wireless networks, every mobile node can function as a router. In other words, the role of mobile connection points is not only to transmit and receive, but also to perform router selection and store-and-forward functions. Additionally, since wireless network Ad Hoc Internet does not require infrastructure construction, the cost of Internet construction is significantly reduced, and network deployment becomes faster and faster, which is very beneficial for responding to emergencies and alleviating communication workload in network hotspot areas.

The wireless network is a multi-hop network. A communication process may require several relays to be completed, and relay nodes can flexibly choose routes to avoid areas with severe interference. Additionally, the wireless network can more effectively utilize wireless resources. When two clients are relatively close, they can communicate immediately. Such communication uses a very small transmission power, and even in multi-hop situations, the total transmission power is smaller than the direct transmission power. This is because the attenuation coefficient of electromagnetic waves is a discrete system, and the coverage area of each client becomes increasingly limited, and the reuse of frequencies is doubled, thereby improving the volume.

Because the self-organizing wireless networked Internet has no fixed network infrastructure (such as communication base stations), it can be constructed and applied at any time and at any location. Its operation method is not limited by a fixed network topology, thus allowing all connection points to be mobile. The addition and removal of nodes will only occur through the interaction of other nodes.

The unmanned aerial vehicle (UAV) network is an autonomous system composed of mobile nodes. Its main characteristics [3-4] include:

（1）The autonomy of the network. Compared with the basic wireless communication network, the major difference of the wireless network internet is that it can maintain communication regardless of any circumstances and without relying on the current basic network infrastructure.

（2）There is no strict control center. The wireless network and the internet do not have strict monitoring centers. The influence of all connection points is equal, and each connection point has its own server and router functions.

（3）Dynamic topology. From the perspective of the transport layer, in wireless network environments, mobile connection points can move randomly within the network at any speed and method. Additionally, there are changes in the transmission output power of devices on the wireless network, interference between wireless channels, and the impact of geographical factors. As a result, the network topology structure generated between connection points due to wireless channels will change significantly at any time.

（4）Multi-hop communication. Due to the nature of wireless telephone data signal dissemination, multi-hop communication is stipulated in the wireless network internet regulations.

2. Routing Protocol Design

2.1　Design Overview

Developing a good routing protocol is the primary issue in establishing a drone network, and it is also a hot and difficult topic of research. Based on the characteristics of unmanned aircraft, designing a computing method for routers that is rapid, precise, highly efficient, scalable, and has strong adaptability becomes an especially important research topic for unmanned aircraft ad hoc networks.

The characteristics of wireless ad hoc networks include self-organization of the network, dynamic changing network topology, limited transmission bandwidth, limitations of mobile terminals, the existence of one-way channels, and distributed control, etc. Designing an efficient and dynamic routing protocol has become a challenge in the overall planning of wireless network ad hoc networks. The routing protocol must be able to keep up with the rapid changes in the network topology structure caused by the movement of connection points [5].

Currently, the conventional wireless ad hoc network routing protocols can be classified into active routing algorithms and on-demand routing algorithms based on the relationship between the timing of route establishment and data transmission. The active routing requires a large amount of overhead for establishing and maintaining the route and has high resource requirements. The main ones include distance vector routing with destination sorting (DSDV), cluster head gateway switching routing (CGSR), and wireless routing protocol (WRP); the on-demand routing needs to calculate the route before transmission, resulting in a large delay, and the main ones include dynamic source routing (DSR), distance vector routing with need (AODV), contact-based routing (ABR), and temporary sorting routing algorithm (TORA).

At present, various routing protocols for wireless ad hoc networks are not yet mature and no corresponding standards have been established. Especially, the network environment, topology structure and communication requirements of the network vary greatly. Simply adopting any of the aforementioned routing protocols cannot completely solve the routing problem [6]. Therefore, the routing algorithms in mobile Ad Hoc networks remain the current research hotspots and challenging issues.

The routing protocol designed in this paper is a table-driven unicast routing protocol (TDFP) (Table Drive FHR Protocol). Each node maintains a complete routing table locally. When there is a need to upload statistics, it immediately looks up the table based on the detailed address of the destination connection point to obtain the detailed address of the next-hop connection point that must be sent to, and searches multiple times at each intermediate connection point. Finally, it reaches the destination connection point with the shortest relative path.

When the routing protocol is running, the pre-set timers will prompt the process to send a broadcast "ribp" (route information broadcast packet) data packet every fixed period of time. The content of this packet includes all the main information of the neighbor node table and the local routing table. Other nodes will use this information to maintain their local routing tables and determine the status of neighboring nodes. After the timer expires, the ribp message assembly process will be initiated. The message is generated by filling in the header information, reading the neighbor node table and routing table information. The message format assembly timer request expiration triggers the ribp message format assembly function. The ribp message format header information content is first added, followed by the loading of the neighbor connection point table information stored in the system software, and then the loading of the routing table information stored in the system software. After obtaining all the above information, the ribp message is generated and forwarded.