Though I am not an expert, I'd like to comment on this: > > Are you suggesting that SpaceCom somehow deliberately degrades the orbital > parameters of satellites such as NavStar and Transit to no better than 500 > metres? If so, it seems a rather pointless degradation as it is so easily > corrected by the user community. The IGEX programme for example, tracks > Glonass and NavStar (and occasionally a few other) satellites to an accuracy of > well under five metres and cumulatively to sub-metric precision, albeit in > relation to the rather wacky PZ-90 datum. > No, there are three different issues here. The NavStars "know" their position, and include that information in their broadcast. Standard elsets can be osculating, and very accurate for a short period; or average, and "doctored" to fit the SGP4 prediction model, which has large imperfections. > > I think it was Albert Einstein who once said that: > > The Truth ought to be expressed as simply as possible, but never more so. > Agreed! ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www2.satellite.eu.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Mon Aug 20 2001 - 21:50:34 PDT