OSGRS is an open source project to provide an open protocol for Assisted-GNSS (AGNSS) development. The protocol is known as GNSS Reference Interface Protocol (GRIP) and it is based on XML. A set of server and client software that support GRIP has also been developed to encourage GRIP usage. The server is called OSGRS and it currently supports a NovAtel OEM3 or OEM4 reference receiver.
AGNSS server provides "assistance" messages to user receivers able to make use of such messages to rapidly acquire weak GPS/GNSS signals. These receivers typically are found within mobile phones and similar devices.
The official webpage for GRIP and OSGRS is
located at:
http://www.gmat.unsw.edu.au/snap/work/osgrs.htm
Source codes and documentation can be downloaded
from the project's SourceForge page:
http://sourceforge.net/projects/osgrs/