A receiver system for navigation signals was built, which demonstrates the concepts, technologies and evaluation methods for the realization of compact array antennas as well as the applicability of corresponding algorithms for digital beamforming and suppression of interferers. The work of the KN Institute included the development of a compact adaptive antenna array with small footprint and the further development and implementation of algorithms for direction-of-arrival estimation of wanted and interfering signals as well as for efficient suppression of interferers and multipath propagation.
The successfully completed system tests and demonstrations were planned and coordinated by KN.
Accurate and reliable positioning with existing and future satellite systems such as GPS and Galileo is crucial in many areas of passenger and freight transport on road, rail, air and sea. However, the high requirements, especially with regard to interference immunity, can no longer be met with commercially available receivers. One way out is the use of receiving systems that have proven to be particularly suitable for effectively suppressing interference signals and multipath reception by using array antennas in conjunction with suitable algorithms for adaptive beamforming and control (e.g. digital beamforming, DBF).
To achieve the desired characteristics of such an array antenna, a minimum number of elements is required, which are usually arranged at a distance of about half a wavelength. The dimensions of this array are therefore naturally much larger than those of navigation antennas consisting only of a single element. For example, a square 3x3 array optimized for the Galileo E1 band (1.575 GHz, free-space wavelength about 19 cm) already has an edge length of about 30 cm. A problem in reducing the distance between the elements is the increasing coupling. By using new concepts and suitable circuit networks, these difficulties can be solved and the dimensions of the array can be significantly reduced.
Until now, the size of the antenna was often an obstacle to its use. A small, compact array offers significantly improved possibilities for mounting on mobile platforms and makes it easier to meet both functional and aesthetic requirements. Antennas that are integrated into aerodynamically optimized supporting structures in a conformal manner, i.e. adapted to the respective surface, can be implemented with significantly reduced effort and less modification of the platform. In addition, optimal solutions can be offered for various platforms and different scenarios.
October 2010 - September 2013