SUPL Cell-Based Positioning Request

Using SUPL to request a cell-based position.

SUPL (Secure User Plane Location) enables a device to communicate with a SUPL server over an IP connection.

All the components responsible for SUPL positioning run on the Symbian platform. The architecture is based on two plug-ins: the SUPL Proxy Protocol module and the SUPL Positioning Message interface. The relationship between the Location subsystem and SUPL is illustrated below. The plug-ins enable information to pass from the network directly to the GPS hardware.

Figure 1. Location subsystem and SUPL extension

If a client application wants to obtain a position without waiting for a GPS service a mobile network can provide a cell-based position, using SUPL.

A cell-based positioning request using SUPL is shown in the following steps.

1. The client must open RPositionServer and open a connection to the server by calling RPositionServer::Connect().
2. The client must then open RPositioner by calling RPositioner::Open() and specify the UID of the Network Proxy PSY.
3. The client application sends a location request to the Location subsystem by calling RPositioner::NotifyPositionUpdate().
4. The Location subsystem forwards the location request to the SUPL Protocol module by calling CLbsNetworkProtocolBase::RequestNetworkLocation(). (In the default configuration SUPL is used for cell-based positioning).
5. The SUPL protocol module communicates with an external SUPL server and obtains a cell-based location.
6. The SUPL Protocol Module returns the cell-based position by calling MLbsNetworkProtocolObserver::ProcessLocationUpdate().
7. The Location subsystem completes the client request.