A 20-day-old girl was referred to our clinic for systolic murmur, cyanosis, and dyspnoea with feeding. Echocardiography revealed an atretic aortic valve. CT angiography scan revealed that the left common carotid artery originated from the distal main pulmonary artery. The plan was patent ductus artriosus stenting and bilateral pulmonary artery banding and then follow-up for any possible future intervention.

Reliability of a satellite attitude control system depends on accurate detection of failures in its sensors. This paper presents an observer for robust detection and isolation of a class of failures in satellite attitude sensors. The proposed observer uses measurement of a three-axis gyro together with only one attitude sensor, and generates a residual signal which is sensitive to faults and is simultaneously robust against disturbance and noise. A nonlinear model of satellite kinematics is considered for design of the observer. The structure of the observer is in the form of a delayed continuous-time differential equation ensuring its robustness properties. A realistic simulation is provided to illustrate the performance of the proposed observer in the face of the faults occurring in a magnetometer, as the attitude sensor, and also the faults occurring in the gyro.