  Hardware and software architecture of a novel spacecraft Attitude
Determination and Control System (ADCS) based on smartphones using Variable
Speed Control Moment Gyroscope (VSCMG) as actuator is proposed here. A
spacecraft ground simulator testbed for Hardware-in-the-loop (HIL) attitude
estimation and control with VSCMG is also described. The sensor breakouts with
independent micro-controller units are used in the conventional ADCS units,
which are replaced by a single integrated off-the-shelf smartphone. On-board
sensing, data acquisition, data uplink/downlink, state estimation and real-time
feedback control objectives can be performed using this novel spacecraft ADCS.
The attitude control and attitude determination (estimation) schemes have
appeared in prior publications, but are presented in brief here. Experimental
results from running the attitude estimation (filtering) scheme with the
"onboard" sensors of the smartphone in the HIL simulator are given. These
results, obtained in the Spacecraft Guidance, Navigation and Control Laboratory
at NMSU, demonstrate the excellent performance of this estimation scheme with
the noisy raw data from the smartphone sensors.
