DE-link, an antenna pointing system for stratospheric balloons

G. Johansson, J. Selinder, K. Hyyppä EISLAB, Luleå University of Technology SE-971 87 Luleå Sweden

Abstract

The DE-Link attitude determination and pointing system onboard stratospheric balloons provides a low cost, low weight and high accuracy method to increase the efficiency of WLAN communication between balloon and ground station. By determination of the 6-dimensional pose of the balloon gondola in real-time, the WLAN antenna can be pointed toward a known position on the ground. This removes the need for power-consuming omni-directional antennas. It also gives an improvement in communication speed and reduction of overall weight by the removal of heavy RF power amplifiers. The design uses a combination of GPS receivers, accelerometers and magnetoresistive circuits to determine the absolute attitude and position of the gondola in real-time, and two DC motors to point the antenna in azimuth- and elevation directions to compensate for the movements of the gondola. Ground based tests have shown the system to function well with a pointing error of less than ±2◦ .