AMF Phasing - A precise control of the ignition timing of AKM for reduction of the injection error
- Paper ID
IAF-82-322
- author
- company
NASDA
- country
Japan
- year
1982
- abstract
This paper deals with a new concept, named "AMF Phasing", which intends to minimize the effect of injection error that would result during apogee motor firing (AMF) of the spinning spacecraft. The characteristic of velocity increment error is derived analytically, based on the disturbed spinning motion during AMF. In order to precisely estimate the amount of fuel required for post-AMF orbital correction maneuvers, a probability model is proposed which estimates the total injection error probability combining the dominant error factor, i.e., pre-AMF attitude determination error and velocity increment error during AMF. It is shown that a substantial saving in fuel normally consumed, for post-AMF can be expected, when the resultant velocity increment error' contribution, which otherwise would be randomly directed in inertial space, is controlled so that it appears in the direction of local right ascen- tion by igniting AKM at the proper instant (AMF phasing). The procedure for AMF phasing, using sun pulse as a reference signal for the ignition timing is described in this paper. It was actually applied for GMS-2, Japan's second Geostationary Mèteorological Satellite (HIMAWARI-H ). The Himawari-H post-AMF orbit determination shows that AMF phasing worked successfully and it is concluded that a substantial fuel saving was achieved.