An Efficient Acquisition Scheme for a High Sensitivity Assisted GPS Receiver

Zhixing LIU  Chunming FAN  Shoichiro ASANO  Nobuhiro KISHIMOTO  Harumasa HOJO  Akio YASUDA 

Publication
IEICE TRANSACTIONS on Communications  Vol.E92-B  No.5  pp.1875-1883
Publication Date: 2009/05/01
Online ISSN: 1745-1345
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Navigation, Guidance and Control Systems
Keyword: 
AGPS,  timing-synchronized 3G cellular network,  acquisition,  TTFF, 

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Summary: 
Automatic location identification is required for emergency calls in Japan and many other countries. However, promptly providing a reliable position is a problem in places where the global positioning system (GPS) signal is extremely weak. We propose an acquisition scheme for the assisted GPS (AGPS) architecture based on a timing-synchronized mobile network. System errors as well as code uncertainty range and frequency uncertainty range are discussed. With this method, the acquisition search range is significantly reduced, and a long-time coherent correlation is made possible. Simulations and experiments prove that the method is fast, efficient and power-saving for the user handset. Furthermore, the AGPS receiver can perform a short TTFF (Time To First Fix) start even with no ephemeris kept in the handset.