GPS World, January 2011
Personal Navigation WIRELESS LBS FIGURE 6 IEGLO KBD module architecture FIGURE 7 Modules of Test User Terminal FIGURE 8 GPS EGNAS EDAS Number of satellites FIGURE 9 GPS EGNOS EDAS Height plot a key piece to properly perform qualitative state estimation The IEGLO approach is implemented architecturally to allow to input and removal of data about a specifi c individuals motion habits FIGURE 6 depicts the architecture of the kinesic behavior detection KBD module the software platform where these qualitative navigation concepts have been implemented Position Augmentation Test To test the augmentation service a test user terminal TUT has been specifi ed and assembled The TUT uses two identical GPS EGNOS receivers interfaces directly with the augmentation server and processes the position response One receiver has been confi gured to output GPSonly position information the other to use EGNOS corrections for the position computation The position of the GPS only receiver was forwarded to the augmentation server The EDAS SiSNeT corrected position information was routed to the EDAS fi le database In this manner three different calculated positions of one point per epoch are available GPS only GPS EGNOS and GPS EDAS SiSNeT see FIGURE 7 A low cost patch antenna providing single frequency L1 output was used for the tests connected to an antenna splitter A notebook computer provided an interface to a GSM GPRS module and to the receivers An April 2010 test was conducted in the area surrounding an assisted living home FIGURE 8 shows the number of satellites used for positioning during the measurement campaign The area around the building was very hilly so satellite signals were exposed to shadowing effects at the beginning and at the end of the measurements The middle of the campaign had good satellite visibility FIGURES 9 13 show the user trajectory during the dynamic measurement For better readability longitude latitude and height values were reduced by the mean value of the corresponding coordinate Therefore the zero line in the yaxis of each plot symbolizes the mean value of the whole measurement The same confi guration is used for the fi ve plots Figure 9 demonstrates the good performance of the augmentation server concept regarding the height solution The ionospheric delay which can be corrected with the EGNOS signal particularly infl uences the height component of the position Thus the potential of the EDAS SiSNeT based correction is seen in the height plot Figures 10 to 13 show the longitude and the latitude of the different solutions Two plots of each coordinate were used the fi rst one shows the coordinates during the whole measurement and the second one emphasizes the time interval between second 51820 and second 51890 www gpsworld com January 2011 GPS World 69
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