****************************************************************************** DORISMail 17-Sep-2001 10:14:59 Message No 0140 ****************************************************************************** Author: Bonhoure Bernard Subject: DORIS mail pour Cycle 329 T/P non alterne Bonjour, Pourriez-vous faire passer l'info suivante en Anglais par DORIS mail? Merci. Bernard BONHOURE (CNES/DSO/ED/AL/MA) ------------ Subject : Chained Measurements for DORIS instrument on TOPEX/POSEIDON during Cycle 329 The DORIS instrument on the TOPEX/POSEIDON satellite, was set to Chained Measurement during Cycle 329 19-29 August 2001. This functioning mode has been used to have a Reference Cycle, for a future comparison with DORIS/JASON. When measurements are chained, the Doppler measurement is done over 10 seconds instead of 7 seconds, so that the noise of Doppler count every 10 seconds is lower (better). The drawback is that with chained measurements, only one beacon can be measured over a pass. With the nominal measurement mode, when they are two beacons in visibility, the instrument alternates between the two beacons every 10 seconds, which results in more measurements, typically 80-85% nominaly versus less than 70% with chained measurements. Best Regards, Bernard BONHOURE, CNES, T/P and DORIS Mission Operations Manager