From b4bbac8d5c3835a0c6516e40b2fdcdc42848e17a Mon Sep 17 00:00:00 2001 From: Refik Hadzialic Date: Wed, 6 Jun 2012 18:47:38 +0200 Subject: GPS Picture --- vorlagen/thesis/src/kapitel_A.tex | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'vorlagen/thesis/src/kapitel_A.tex') diff --git a/vorlagen/thesis/src/kapitel_A.tex b/vorlagen/thesis/src/kapitel_A.tex index 35a0367..444bb77 100644 --- a/vorlagen/thesis/src/kapitel_A.tex +++ b/vorlagen/thesis/src/kapitel_A.tex @@ -430,6 +430,22 @@ To increase the speed of measurement report, reference time can be used to provi information for the A-GPS in the MS of target entity. This field is of boolean type, if set to true, reference time is included in the sent packets. +Since the sent packets are not transmitted in real time but put on a stack and +then sent to the MS, a time delay exists. A solution to this problem is to +add extra seconds to the reference time being sent. In order to assess +the amount of extra seconds to add, the GSM operator is required experimentally +to verify his/her findings. \todo{see how much the reference time can deviate from current time}. + +The reference time being sent to the MS is Coordinated Universal Time (UTC). The GPS device +receives UTC time from the satellites and adjusts the computer time. To set the correct +time, time zone offset of the BTS ought to be set correctly. + +Finally, the refresh time of downloading new almanac and ephemeris data has to be set. +The variable uses the hour unit, how often the data are being downloaded. If the data are +used from a local GNSS station, refresh time of the ephemeris data should be set to +every 30 minutes or 0.5 hours. The almanac data are valid for up to 180 days \citep{GPS-Guide} but are updated +usually every day\footnote{Almanac update times can be found here: +\url{http://www.navcen.uscg.gov/?pageName=currentNanus&format=txt}} \citep{GPS-Pentagon} \newpage \section{Sourcecode} -- cgit v1.2.3-55-g7522