The EU-funded 'Signature' project has achieved a major milestone, delivering a new, open-source, EGNOS-based application for GPS-equipped smartphones, including the Google Android.
EGNOS in your smartphone. © Signature.According to the first GSA GNSS Market Report, issued on 1 October 2010, some 20% of today's European mobile phones include a GNSS chipset, with market penetration expected to exceed 50% in the next five years. However, the majority of these chipsets are not EGNOS-ready.
The Signature project's uses EGNOS correction data via the internet – using free services such as EDAS or SiSNeT – and then applies them to the GPS position calculated by your mobile phone’s internal GNSS chipset.
Overcoming GNSS chipset limitations online
Applying the corrections is not an easy task, say project partners. The system relies on some innovative techniques for position calculation, requiring the development of novel software. With Signature's new 'library of functions' for the Google Android mobile operating system, location-based service (LBS) application developers have a powerful set of tools for creating fresh EGNOS-based applications.
More accuracy for 'Location-Based Services'
Improved accuracy can bring benefits in environments where applications are more demanding and map-matching is not possible, e.g. pedestrian guidance, social LBS and outdoor applications.
Although GPS positioning errors in urban areas are mainly due to multipath and GPS satellite availability, EGNOS corrections on GPS satellite clocks and orbits and the ionospheric correction model can still add value in such cases.
Moreover, GPS stand-alone accuracy is expected to degrade in the next couple of years as solar activity increases. The availability of free EGNOS corrections delivered via the mobile communication network will help in maintaining accuracy during these high solar activity periods (see F. Froment and E. Tapias, 'Assessment of EGNOS performance under worst ionospheric conditions observed in October 2003').
Algorithm replicates conventional EGNOS
The new Signature algorithms have been shown to closely replicate conventional EGNOS performance. Tests have been successfully conducted using several Android phones such as HTC Wildfire, Desire and Legend.
Certain assumptions regarding the phone chipset positioning algorithm are essential to ensure good performance, something that needs to be considered for future application development. In some cases, direct co-operation with chipset manufacturers may be necessary in order to understand the positioning techniques being used. Developers would then need to judge the significance of any potential positioning improvement for their intended user application.
More information:
- EGNOS test application for Android
- Test application’s user installation and operations manual
- Technical report on the EGNOS library development
For access to the EGNOS library source code, send your name, the name of your organisation and your e-mail address, along with a brief description of the proposed application and target platform to: research@gsa.europa.eu.