Communication System Design

The Communication System for the Unmanned Aerial Vehicle was divided into two parts:

1. Wireless Network from Base station to the Primary UAV

2. Wireless Network from the Primary UAV to the Secondary UAV

Primary Vehicle

The primary vehicle is equipped with an 802.11b Wi-Fi LAN adapter. The on-board unit comprises a Senao Wi-Fi USB adaptor of 80mW output power with 23dbi gain and a sensitivity of -93dbm.

Secondary Vehicle

The secondary vehicle is equipped with a camera that relays the video automatically on an 802.11b network. This video is transmitted to the promary vehicle. The primary vehicle then processes the video and also relays it back to the base station.

Base Station

At the base station end the system comprises of a wireless access point, fed with a 1W signal booster, an omni directional antenna of gain 9dbi and an antenna mount for line-of-sight communication. The net transmitted power was checked to be within the total power dissipation allowed. This setup was tested for a range of approximately 3Kms with almost no loss of connectivity.

Data Flow

The management of flow of video was implemented as a web service in ASP.NET 2.0. The images are sampled are 7 frames per second and are transmitted over the wireless network. When the secondary vehicle is deployed form the primary vehicle, the web service relays the video transmission from the secondary vehicle, to application running at the base station.

The kill switch is implemented on an analog wireless link working at Channel 55.