Spiegel, D.; Grasso Toro, F.; Schnieder, E.:
A New Methodology towards GNSS-Receiver Evaluation in Non-perfect Signal Reception Environments .
ENC-GNSS 2014 - European Navigation Conference, Rotterdam, Niederlande, April 2014.
Since more and more GNSS systems are available or will be build up in the near future, the determination of the receiver’s quality is currently part of the research at many research institutions. Especially for the end-user it is essential to be able to determine which receiver is the most suitable for their specific applications.
One key performance measure for the choice of the receiver is position deviation or accuracy. The receiver’s accuracy is often indicated as a certain amount of meters in an urban, rural or open environment. The definition of these environments and the time of measurement are generally not mentioned, not enabling to compare multiple receivers. Therefore, a new methodology to describe the environmental conditions during the receiver examination is needed.
For that reason, different environments such as urban, rural and open have been defined in terms of street width, height of surrounding buildings and driving speed; and measurements with an approved reference system have been performed. The driven test trajectories and the surrounding buildings are subsequently simulated to enable the theoretical conditions for the satellites. The results of the simulations show the number of satellites directly visible in the sky. Based on the theoretical visible number of satellites the theoretical dilution of precision (DOP) values can be calculated. Merging and weighting the DOP with the variation of the signal to noise ratio over the driven scenarios a final measure for the grade of difficulty for a certain scenario can be determined. This grade of difficulty can then be used to describe different environments for kinematic application and enable a first step towards the comparison of GNSS receivers.
Summing up a methodology has been developed to describe the measurement conditions for kinematic scenarios. Based on the methodology every driven test scenario can be provided with a level of difficulty, enabling to understand under which conditions the quality assessment was performed. Furthermore, the measurements are the first step towards the comparability of multiple receivers, which can be tested empirical at different times and in different environmental conditions, helping the end-user with the selection of the most suitable receiver for specific applications.