SARHA – Development of a Sensor-Augmented GPS/EGNOS/Galileo Receiver for Urban and Indoor Environments
The main objective of the project ‘SARHA - Sensor-Augmented EGNOS/Galileo Receiver for Handheld Applications in Urban and Indoor Environments’ is the development of a modern satellite navigation receiver with autonomous sensor augmentation. Additionally, the hybrid navigation system will be enhanced by a transponder capable of receiving absolute position updates from transmitters installed inside buildings. The transponder will allow the SARHA system to significantly increase reliability and accuracy of the positioning solutions indoors. The hybrid navigation software is split up into two parts. The first one will be implemented directly on the GPS receiver, whereas the second part will run on a microcontroller. Thus, a small, low-performance microcontroller can be used, representing the first step towards the reduction of size, weight and power consumption of the mobile system. This paper provides an overview on personal mobility and typical applications related to the system, describes the system architecture and the hybrid navigation software in detail. Furthermore, emphasis is laid on a comparison of different step detection algorithms, showing their advantages and disadvantages. Based on the Galileo signal definition, additional analysis set up to explore the signal characteristics in comparison to the GPS signals, are provided. Improvements due to the Galileo signal availability in urban and indoor environments are assessed and will later ensure seamless integration of enhanced technologies into the continuous developments.