Date: Mon, 28 Jun 2004 19:11:19 +0000 (GMT) From: flemoine@bowie.gsfc.nasa.gov Reply-To: Frank.Lemoine@gsfc.nasa.gov To: Jean-Jacques Valette , feissel@ensg.ign.fr Cc: flemoine@bowie.gsfc.nasa.gov, ramesh.govind@ga.gov.au, john.dawson@ga.gov.au Subject: Re: attitude for SPOT-2 and Envisat Dear Jean-Jacques and Martine, Greetings from the Northern Hemisphere. WOuld it be possible to obtain a clarification as to what attitude algorithm is used on SPOT-2 and ENVISAT? The documentation for SPOT-2 which is online says geocentric. Now Topex follows a *geodetic* profile (ie +Z, nadir, is geodetic). My guess is that ERS/ENVISAT must as well. If so what ellipsoid and what flattening do they use in flying the spacecraft? Same question for SPOT-2. The rationale behind my question is the verify that we have the correct pointing for these spacecraft in GEODYN. This would affect the measurement offset correction that we compute and might have a bearing on the problems which we see on Envisat that I mentioned last week while still in Canberra. SPOT-2 modelling in GEODYN is definitely geocentric. I'm still deciphering the ERS/ENvisat routine in GEODYN. Thanks A+, Frank