GPS World, February 2018

UNX200AUS J03 S1C S1X S2X S5X JAVAD TRE_ G3TH DELTA 65 60 55 50 45 40 35 30 25 20 15 10 65 60 55 50 45 40 35 30 25 20 15 10 with range corrections and integrity information for aviation applications in particular The SLAS and SBAS signals are transmitted via dedicated antennas but they are phase coherent with the GPS compatible navigation signals transmitted via the main L band antenna The L6 signal provides the Centimeter Level Augmentation Service or CLAS formerly the L band Experiment or LEX on all QZSS satellites but employs a different signal structure for Block I L61 and Block II L62 An overview of the various L band signals and corresponding PRN assignments is given in TABLE 3 QZS 3 also provides the QZSS Safety Confirmation Service Q ANPI to support rescue operations with S band communication in case of a disaster The total transmit power is 500 watts for the Block II IGSO satellites and 550 watts for the GEO satellite QZS 3 4 SIGNAL TRANSMISSION Tracking of the QZS 3 L1 C A and L5 signals by receivers in the German Aerospace Center Deutsches Zentrum für Luft und Raumfahrt or DLR and International GNSS Service networks started on Sept 10 2017 at 09 04 UTC followed by the L1C and L2C signals at 09 27 UTC L5 tracking started with a very low carrierto 46 GPS WORLD WWW GPSWORLD COM FEBRUARY 2018 noise density ratio C N 0 of 10 20 dB Hz that increased to 50 55 dB Hz shortly after the activation of the L1C and L2C signals QZS 3 broadcast ephemerides were first transmitted on Oct 4 2017 at 16 00 UTC However tracking of the L1 L2 and L5 navigation signals with common geodetic receivers is currently limited to receivers with experimental firmware versions developed by three different manufacturers Signal transmissions from QZS 4 started on Nov 1 2017 The first L1 C A signals of PRN J03 were received at 02 50 UTC At the same time L5 signal transmission started but this signal was only tracked by a very limited number of receivers due to its low signal strength resulting in a C N 0 of only about 15 dBHz At 03 14 UTC an increase of the C N 0 by about 40 dB occurred and many additional receivers started 5 C N 0 dB Hz 2017 11 02 2 Nov 6h 12h 18h UNX200AUS J06 S1C S1X S2X S5X JAVAD TRE_ G3TH DELTA 5 C N 0 dB Hz 2017 11 02 2 Nov 6h 12h 18h FIGURE 3 QZS 4 signals tracked by DLRs Javad Delta 3TH receiver in Sydney Australia The top plot shows the standard code PRN J03 and the bottom plot the non standard code J06 The measured C N 0 is shown for L1 C A black L1C blue L2C red and L5 green