I thought I had seen something regarding this before, and sure enough here it is:
<http://www.freqelec.com/gps_gnss/waas_for_telecom_wp_5-06.pdf> <http://hugofruehauf.com/pdf/24-WAAS_for_Telecom_2003-upd_2011.pdf> <http://www.dtic.mil/dtic/tr/fulltext/u2/a485380.pdf> All variations on the same idea - essentially point a DBS dish at a WAAS satellite. Indications are that WAAS alone can be used for timing and the articles specifically touch on GPS backup and jamming resistance. Each article is a bit different so suggest reviewing all of them. I guess it's an open question if your receiver can use WAAS alone for timing. I don't have one to test with, but does anyone know if the LEA-6T supports this mode? It would seem so. Paul - K9MR On Jan 8, 2014, at 5:14 AM, Brian, WA1ZMS <wa1...@att.net> wrote: Hal- Maybe *I* don't understand the WAAS data stream then. In the case of a common-view single satellite timing "transfer" or calibration like is done every day by NIST, et al., could not a WAAS SVN be used for such an application? I short, my idea was to use just such a fixed common-view single WAAS SVN as the common source of 1PPS. Now if the WAAS data format does not fully replicate a classic GPS satellite, then yes my idea is all hog-wash. As I said before, usual hold over during jamming events is working fine. But an idealy placed GPS antenna with full 360 degs of azimuth view only helps to hear more RF jamming sources in heavy urban environments. The result is our customers see log files that show sometimes frequent (say once every 10 days) events where BOTH the active and hot standy by GPS timing receivers go into hold-over from jamming. My desire is to try and mitigate the appearence that our critical RF comm systems are of poor quality since there are these hold-over events taking place more often today than say 5 years ago. We do not build the timing receivers, but we buy brand X. Switching to brand Y as a new vendor and getting them qualified is painfull. Thus my original thought of trying a narrow beam width fixed antenna aimed at a WAAS satellite to reduce the effective antenna apperature and not "hear" the cars and trucks on the highways with their personal GPS jammers as they drive by a classic GPS antenna. Does that help explain it? Or does WAAS not offer a classic 1PPS signal in it's data stream? I thought it had to in order to offer compatability. -Brian, WA1ZMS/4 iPhone _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
