Re: Letter designations for sources of elements

Jim Varney (
Thu, 10 Jun 1999 21:20:54 -0700

On 9 Jun 99, Philip Chien wrote:

> Jim Varney <>
> >Since you are with ARINC I now see how this might be problem for you.
> >Future releases of the GPS elsets will have the "U".
> Hold on a second!  "U "has a very specific meaning - e.g. unclassified
> objects generated by USSPACECOM.
> How about "D" for derived for elsets generated through state vectors and
> other analysis of refined orbital information (like GPS element sets
> reverse engineered from the ephemeris data and even space shuttle elements
> derived from the shuttle's state vector)?

A good suggestion, along with other good suggestions for alternatives to 
"U" for unofficial TLEs.  If consensus is reached on a new code and it is 
put into practice, I'll be happy to adhere.  In the interim I'll be using 
the "U" in the unofficial GPS elsets as they are updated weekly.

 -- Jim

Jim Varney        -121.398 W, 38.457 N, 10m
Member, Sacramento Valley Astronomical Society
GPS Elsets