“Peers-based aiding GNSS” [1] refers to collaborative systems composed by GNSS receivers that exchange aiding data in order to improve their performance. One of the main issues related to this type of systems is the time synchronization between receivers. The required precision of the synchronization depends on the type of data the receivers exchange. This paper presents a new technique devoted to solve the synchronization problem in a network of collaborative users, equipped with low cost GNSS receivers. Such a technique is based on the joint processing of the same GNSS signal received at different nodes of the network and exploits some attributes of the GNSS signal to evaluate the synchronization offset. The paper describes the new technique with the appropriated theory and gathers the results of some measurements performed in a real scenario. Moreover, on the basis of the clock offset estimate, an acquisition algorithm for aided GPS systems has been developed and tested in a real indoor application.
[1]
F. Dovis,et al.
An assisted high-sensitivity acquisition technique for GPS indoor positioning
,
2008,
2008 IEEE/ION Position, Location and Navigation Symposium.
[2]
D. W. Allan,et al.
Accurate Time and Frequency Transfer During Common-View of a GPS Satellite
,
1980
.
[3]
Edoardo Detoma,et al.
Precise time and frequency distribution over a wireless network for A-GNSS users
,
2009,
2009 IEEE International Frequency Control Symposium Joint with the 22nd European Frequency and Time forum.
[4]
Elliott D. Kaplan.
Understanding GPS : principles and applications
,
1996
.
[5]
Gérard Lachapelle,et al.
GNSS Indoor Location Technologies
,
2004
.