High-Sensitivity GPS - an Availability, Reliability and Accuracy Test

High-Sensitivity GPS receivers shall deliver positions in shadowed areas as well as inside buildings due to their sensitivity with respect to GPS signals with a power ratio below -150 dBm, The paper shows a comparison for three high-sensitivity GPS receivers used in static mode regarding availability, reliability and accuracy in areas with free horizon, in shadowed areas as well as indoor, The investigations show that the availability rate indicates more than 90 % for shadowed areas, Inside buildings with low attenuation and in rooms with windows the availability ranges between more than 70 % and 18 % depending on the receicer type. For free horizon conditions the reproducability standard deviation shows values between 3.75 m and 7.33 m. Inside buildings the respective standard deviation is degraded to more than 80 m. More inside the building, e.g, in a windowless room or a cellar, no GPS signals are received. Additionally kinematic measurements were carried through too. Here the availability reaches values of around 97 `7o for the track including shadowed areas and even tunnels. The reproducability standard deviation indicates values between 4,92 m and 12.22 m. Obviously the kinematic results are more accurate than static results, due to a filter for the positions using a movement model.

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