Alexander Steingass

Characterization of the aeronautical satellite navigation channel through high-resolution measurement and physical optics simulation

In this paper we discuss the results of a measurement campaign investigating the environment of satellite navigation receivers for aeronautical applications, where reflections on the plane as well as from the ground decrease the accuracy of the positioning. The focus is on the most critical flight phase—the final approach. For this scenario a wideband model is derived, which allows to investigate the performance of present and future global navigation satellite systems. The work was carried out under an European Space Agency contract (ESTEC Contract number 16059/02/NL/DS) entitled ‘Navigation signal measurement campaign for critical environments’, by Joanneum Research (Austria) with subcontracts to DLR (Germany) and the University of Vigo (Spain). Copyright

Signal simulations in urban environments

This publication explores the influence of a realistic multipath channel model to satellite navigation applications in urban environments. In this context we have discovered that there is a tradeoff between accuracy and robustness concerning the bandwidth. While narrow band signals such as GPS C/A, BOC (1,1) proved to be robust especially under shadowing situations the wideband signals lost lock very likely in the shadowing situation while being more accurate in LOS situations. In severe multipath situations we have been able to prove the performance of the particle filter receiver wich is clearly showing a better performance than the conventional receivers and even than a maximum likelihood estimation DLL. Furthermore we have identified critical situations where receivers tend to loose lock.

Land mobile multipath channel reduction effects on a real GNSS receiver

One of the current limitations to evaluate the impact of a realistic multipath environment over a GNSS receiver is the high number of multipath rays that are needed to model the channel in a HW RF constellation simulator. That makes necessary the application of reduction techniques to decrease the number of channels per satellite to be simulated. The initial evaluation of two reduction techniques based on the solution of optimization problems is presented for an urban vehicle scenario, focusing the study on the evaluation of the multipath effect over code pseudorange measurements.

GNSS receiver performance assessment with a realistic aeronautical channel model

A multipath model for the aeronautical channel, which was derived from a channel measurement campaign, has been implemented into hardware simulators. The way of implementation is described in detail and simulation results obtained with a GNSS receiver and showing the impact of multipath are presented.