GPS World, June 2009
GPS Modernization INNOVATION PRN G01 2009 04 29 20 10 00 10 20 MP C5X meters PRN G01 2009 04 29 18h 21h 30 3h GPS Time MP C5Q meters 20 10 00 10 20 Å FIGURE 9 Pseudorange multipath and receiver noise of SVN49 PRN G01 L5 tracking for a selected pass over Oberpfaffenhofen Germany on April 29 30 2009 Top receiver type J with geodetic antenna Bottom receiver type N with a Galileo antenna The satellite exceeded an elevation angle of 50 between 20 30 and 23 30 with a peak elevation angle of 80 near 22 00 signal a valuable basis for experimentation in aviation applications or triple frequency processing To assess the quality of the raw GPS measurements we made use of the so called multipath combination of pseudorange and carrier phase measurements The combination is essentially the difference between the PRN E52 2009 04 17 20 10 00 10 20 MP C5X meters 3h 6h 9h GPS Time Å FIGURE 10 Pseudorange multipath and receiver noise of GIOVE B L5 tracking for a high pass over Oberpfaffenhofen Germany on April 17 2009 using receiver type J pseudorange and carrier phase measurement on the L5 frequency and therefore measures the sum of the pseudorange multipath M and noise Due to the opposite sign of ionospheric path delays on code and phase measurements an ionospheric correction is used in the multipath combination which requires phase measurements on a second frequency in this case L1 The individual carrier phase biases are furthermore aggregated into a common bias b Other than in a traditional zero baseline test the multipath combination neither requires a second receiver nor a second satellite transmitting the same signal in space It is therefore best suited for studying the tracking performance of the new GPS L5 test signal Results for receiver types N and J obtained at DLR Oberpfaffenhofen are shown in FIGURE 9 for a sample high elevation angle tracking pass Despite obvious differences that can be related to the specific multipath environment and code smoothing strategies for the two receivers a high quality is obtained in Starlink GPS Products By Raven Industries Inc Global Positioning Solutions since 1991 Product Lines Line Amplifiers Down Up Converters Fiber Optic Converters Bias Tees Splitters 800 460 2167 Visit our Web Site www starlinkdgps com www gpsworld com June 2009 GPS World 57
You must have JavaScript enabled to view digital editions.
