> Brooke, > > The traditional GPS has C/A and P(Y) on L1 and P(Y) on L2. > Most Civilian GPSes only uses C/A. > Advanced receivers can also use P(Y) code, since the P-code is known, > the hand-off to P code is known and the way that P-code is encrypted > into Y-code is known (XOR with another code, called A-code or W-code in > different sources). Modern receivers is able to do both code and carrier > phase observations on the P(Y) code signals.
Read up on semi-codeless tracking, I dont think (pure) codeless is used anymore. http://www.colorado.edu/ASEN/asen6090/ztracking.html https://books.google.se/books?id=-sPXPuOW7ggC&pg=PA240&lpg=PA240 > The military goal of this "break-in" is not lost, as those receivers > still rely on the C/A code and that is easy to jam. Also, the "break-in" > comes at a signal quality loss and the advancement of methods have > reduced this loss. > > The benefit of dual frequency observation is that ionspheric shift can > be almost completely taken out of the error budget, adjusting both code > and carrier phase observations. Then working on the integer ambiguity > you can get carrier phase observations with accurate pseudo-ranges. > Carrier-phase observations has a much higher precision to them, so that > gives a very high precision and using a good reference network > corrections can be adjusted to give good absolute position. > > If civilian receivers where to implement L2C and L5 which now is > becoming common, they would gain quite a bit of precision in a similar > fashion. For car navigation, the GPS would know which lane you are in. There ARE civilian receivers doing this, and has been for quite some years. And its not from only a few vendors - all the big ones have it - Trimble, Novatel, Topcon, Javad, Leica, Septentrio and a few more. There are now receivers tracking "GPS L1/L2/L2C/L5, Galileo E1/E5A/E5B/AltBoc/E6, GLONASS L1/L2/L3, BeiDou B1/B2/B3, QZSS L1/L2/L5" The price exceeds my home hobby budget, but so does a replacement CS-tube a factory new OCXO based GPSDO and many other things you can sometime find at reasonable cost used/recycled. -- Björn _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
