Evaluation And Test Plan Optimizing Of Wireless Communication Terminal A-GPS OTA Performance And Research Of Measurement Uncertainty

A-GPS(Assisted Global Positioning System)is a positioning technology for mobile terminals,which combines network base station information and GPS information.The receiving performance of A-GPS function on wireless communication terminals has directly influence on the using effects,and determines whether the terminal could position fast with high accuracy.The purpose of this paper is to researching OTA(Over The Air)testing technology of A-GPS function on wireless communication terminals,and building a stable and reliable testing system.Based on the detailed measurement uncertainty evaluation of the system,the ultimate goal of this paper is to provide enterprises with comprehensive and efficient testing services.In this paper,technical theory,relevant standards for OTA testing of A-GPS,the existing laboratory test system hardware and test procedure have been analyzed and researched.Based on test standards requirements and investigation of test equipments from different equipment manufacturers,an upgrading plan based on conditions on A-GPS OTA automation test system has been proposed,in hardware aspect,a network simulator SR3420 is used to instead of wireless tester,to simulate cellular mobile communication network and assisted location signaling,and a GPS simulator GSS6700 is used to output GPS signal configuration that standard requires,and the physical connection is also required;In system integration aspect,according to the test standard steps required to set up the test process,and the integration of GPS simulator controlling,network simulation and link controlling,data collection and analysis are done to realize accurate and efficient test.For the purpose of increasing efficiency and automatic reporting,the A-GPS OTA automation test system utilizing modularization design and integration method that meeting CTIA test standards has been built,at the same time uncertainty of the testing system based on RSS method has been evaluated according to testing standards,the total extended uncertainty is 1.64 dB,which comply with the standard.By repeat testing on different samples and comparing with the authority laboratory experiment results,combining the uncertainty of the testing system,inter laboratory comparison results are satisfactory and show that the system has good reliability.