Unmanned Aerial Vehicle (UAV) for Urban Remote Sensing

Abstract

Unmanned aerial vehicles (UAVs) such as an octocopter are a mature technology applied in various fields including geography, biology, archaeology, forestry, agriculture, and photography. UAVs, for example, afford photographers an added dimension in their art. UAVs may be suitable platforms that meet cost-effective solutions for urban planning, however, applications of UAV in urban mapping and remote sensing are in their infancy. UAV platforms can be flown on demand, easy-to-operate, cost[1]effective, and can deliver high resolution images. An automated flight system on a 32-bit single-board computer is employed to minimize errors in flight control, although the craft can be manually controlled. The UAV is equipped with navigational sensors including GPS for position, altimeter for altitude, magnetometer for heading, and accelerometer for tilt and motion. Since the payload of the craft is variable, the craft has adequate lifting capacity of about 3 kilograms. Weight of the craft is reduced by using carbon fiber frame tubes and propellers. For the craft to capture a large field of view, it has to travel a large area to capture mosaic images with a flight time between 10 to 12 min with an imaging system such as a digital camera. To sustain these flight times, a high-capacity 4S lithium polymer battery pack (10,000 to 20,000 mAh) is used, which powers only the motor and the flight control system. Radio telemetry (433 MHz) is used to send and receive data to the flight computer to monitor the aircraft’s systems. A proportional, integral and differential (PID) controller is coded into the flight computer to control flight dynamics. The control system is automatically tuned for trim, roll, pitch, and yaw controls as well as auto pilot. The craft can be flown on fully automatic mode by uploading a flight plan but can be overridden manually and has fail[1]safe systems in case the craft veers from its flight envelope. The theoretical noise produced by the craft at 120m is about 55.22dB which is acceptable as daytime outdoor noise for urban environments.