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<task id="GUID-3E7FBDE5-B580-4C2D-9815-83E04B7D71E1" xml:lang="en"><title>Switching

from Cell ID to Terminal-Assisted Positioning</title><shortdesc>How to get an assisted GPS terminal-assisted position when the

network positioning preference is SUPL.</shortdesc><prolog><metadata><keywords/></metadata></prolog><taskbody>

<context id="GUID-37503598-3E2C-4254-BE48-4806B0D5E2B5">   <p>SUPL

(Secure User Plane Location) enables a device to communicate with a SUPL server

over an IP connection. A client application requests a position from the network

using SUPL. To receive the position the client must be able to connect to

the Location subsystem. The client must then select the Network Proxy PSY

(NPP) module as its source. The NPP module must be configured to use the SUPL

PSY. </p>While the SUPL PSY module can use cell-based positioning, enhanced

cell-based positioning and AGPS terminal-assisted positioning, the SUPL Network

Server may optionally use AGPS terminal-assisted positioning, though this

is not usually advised.<p>With AGPS terminal-assisted positioning the client

application therefore requests a position from the network using an AGPS Terminal.

The steps below describe the process.</p>     </context>

<step id="GUID-B53B2F90-233B-42D8-A083-57DC29B6251C"><cmd>The client must

open a connection to the server by calling <xref href="GUID-0ADC4654-7F7B-3B53-A2F9-7035670F501B.dita#GUID-0ADC4654-7F7B-3B53-A2F9-7035670F501B/GUID-23285930-A1D5-3A97-AED4-E979BFA96FDD"><apiname>RPositionServer::Connect()</apiname></xref>.</cmd>

</step>

<step id="GUID-A66E2C33-E992-4832-93BC-58ACE995A734"><cmd>The client must

then open RPositioner by calling <xref href="GUID-1EAEB7EF-0AC7-37C7-B35F-C9B780FFC575.dita#GUID-1EAEB7EF-0AC7-37C7-B35F-C9B780FFC575/GUID-AF3D9B5F-8025-3AFF-A101-82025520EBD6"><apiname>RPositioner::Open()</apiname></xref> and

specify the UID of the Network Proxy PSY.</cmd>

</step>

sends a location request to the Location subsystem by calling <xref href="GUID-1EAEB7EF-0AC7-37C7-B35F-C9B780FFC575.dita#GUID-1EAEB7EF-0AC7-37C7-B35F-C9B780FFC575/GUID-321F6046-3551-3ACE-B0A3-26D51FAEB477"><apiname>RPositioner::NotifyPositionUpdate()</apiname></xref>.</cmd>

</step>

forwards the location request to the SUPL Protocol module by calling <xref href="GUID-479C43CF-8787-3596-93ED-F03A8E5CA2F5.dita#GUID-479C43CF-8787-3596-93ED-F03A8E5CA2F5/GUID-E52AC2F2-6E42-370B-93EB-48389E062E33"><apiname>CLbsNetworkProtocolBase::RequestNetworkLocation()</apiname></xref>.

(In the default configuration SUPL is used for cell-based positioning).</cmd>

</step>

module communicates with an external SUPL server, which decides to use terminal-assisted

GPS positioning instead of cell-based positioning. </cmd>

</step>

Module requests a measurement update from the Location subsystem by calling <xref href="GUID-A97ABAA7-46B0-3E26-97C6-123C92CCEEE4.dita#GUID-A97ABAA7-46B0-3E26-97C6-123C92CCEEE4/GUID-676C6200-0A3A-331D-9776-17CA53E8A1D7"><apiname>MLbsNetworkProtocolObserver::ProcessLocationRequest()</apiname></xref>.</cmd>

</step>

<step id="GUID-675B9902-D5B8-4292-8F61-6599E7E128FA"><cmd>The Location subsystem

requests a measurement update from the AGPS module by calling <xref href="GUID-A458AA58-8BD6-303B-89E5-C99000376615.dita#GUID-A458AA58-8BD6-303B-89E5-C99000376615/GUID-C5784C56-C6BA-3D11-AFEB-D08CA8E3E083"><apiname>CLbsLocationSourceGpsBase::RequestLocationUpdate()</apiname></xref>.</cmd>

</step>

<step id="GUID-1C189927-94B0-4EED-BA3B-318A6D7E2E34"><cmd>The AGPS module

produces a position update by calling <xref href="GUID-CE22C141-E1DC-38BB-AC11-76853A7B2590.dita#GUID-CE22C141-E1DC-38BB-AC11-76853A7B2590/GUID-170901F1-435D-3BC1-985B-49BA0876BD92"><apiname>MLbsLocationSourceGpsObserver::UpdateLocation()</apiname></xref>.</cmd>

</step>

<step id="GUID-ACF90C9D-DD31-4990-84E6-435AA802E564"><cmd>The Location subsystem

forwards the measurement update to the network by calling <xref href="GUID-479C43CF-8787-3596-93ED-F03A8E5CA2F5.dita#GUID-479C43CF-8787-3596-93ED-F03A8E5CA2F5/GUID-A4F669B3-52D7-32B7-A2B6-76F5C9B954E2"><apiname>CLbsNetworkProtocolBase::ProcessLocationUpdate()</apiname></xref>.</cmd>

</step>

<step id="GUID-5B71C7FE-FB91-4096-9DCD-3C8053862213"><cmd>The measurement

is sent to the SUPL server, which calculates and returns the position.</cmd>

</step>

module returns the cell-based position by calling <xref href="GUID-A97ABAA7-46B0-3E26-97C6-123C92CCEEE4.dita#GUID-A97ABAA7-46B0-3E26-97C6-123C92CCEEE4/GUID-CAB9645E-91AD-326B-8803-45F28505CCCC"><apiname>MLbsNetworkProtocolObserver::ProcessLocationUpdate()</apiname></xref>.</cmd>

</step>

<step id="GUID-A0638E54-9F51-468E-9DD3-B43A0C0AAAAA"><cmd>The Location subsystem

completes the client request.</cmd>

</step>

</steps>

<result id="GUID-9E3C75F6-B100-440A-B02A-C745374139E9">SUPL has enabled the

client application to receive the AGPS terminal-assisted position from the

network. </result>

</taskbody><related-links>

<link href="GUID-547161C2-BE55-4248-92EE-63612D64F480.dita"><linktext>SUPL Cell

Based Positioning Request</linktext></link>

<link href="GUID-299B6CAB-3D4C-4FA5-A00E-244D04F0B6AB.dita"><linktext>Control Plane

Cell Position Attempt Fallback to SUPL</linktext></link>

</related-links></task>