Next: Kalman Filtering in Chandra Aspect Determination . ... The Science Instrument (SI) background monitoring is one such thread that is designed to compile a temporally and spatially ordered table of the observed flux and energy spectrum in detector coordinates. ... As part of the M&TA System (Wolk et al. 2000) the SI Background (SIB) monitoring thread is based on C++ tools designed with object oriented design methodologies that provide flexibility for generating SIB maps. ...