The on-orbit alignment of the antenna beams of both the X-band and C-band radar systems during operations of the shuttle radar topography mission/X-band synthetic aperture radar (SRTM/X-SAR) was a key requirement for achieving best interferometric performance. In this paper, we consider the X-SAR antenna beam alignment in azimuth. For a single-pass cross-track SAR interferometer, we establish t...

the air transport industry is seeking to manage risks in air travels. its main objective is to detect abnormal behaviors in various flight conditions. the current methods have some limitations and are based on studying the risks and measuring the effective parameters. these parameters do not remove the dependency of a flight process on the time and human decisions. in this paper, we used an hmm...

Micro aerial vehicles (MAVs) pose specific constraints on onboard sensing, mainly limited payload and limited processing power. For accurate 3D mapping even in GPS denied environments, we have designed a light-weight 3D laser scanner specifically for the application on MAVs. Similar to other custom-built 3D laser scanners composed of a rotating 2D laser range finder, it exhibits different point...

Micro aerial vehicles (MAVs) pose specific constraints on onboard sensing, mainly limited payload and limited processing power. For accurate 3D mapping even in GPS-denied environments, we have designed a lightweight 3D laser scanner specifically for the application on MAVs. Similar to other custom-built 3D laser scanners composed of a rotating 2D laser range finder, it exhibits different point ...

Increased ocular positioning misalignments upon exposure to altered gravity levels (g-levels) have been strongly correlated with space motion sickness (SMS) severity, possibly due to underlying otolith asymmetries uncompensated in novel gravitational environments. We investigated vertical and torsional ocular positioning misalignments elicited by the 0 and 1.8 g g-levels of parabolic flight and...

conclusions: thus, identifying the hf patients before the flight and providing them proper education about the events that may occur during flight is necessary. results: hf patients are more prone to experience respiratory distress, anxiety, stress, cardiac decompensation, and venous thromboembolism (vte) during air travel. although stable hf patients can tolerate air travel, but those with acu...

Micro-Doppler (MD) caused by the motion of the ballistic missile can contribute to successful recognition of the ballistic missile. Considering the real observation scenario. This paper proposes a method to derive the MD image of the ballistic missile by applying the range-Doppler algorithm (RDA) based on the real flight scenario and analyzes the factor for the real-time MD imaging. Simulation ...

This paper presents a method for on-orbit calibration of photodiodes for sun sensing in an attitude determination system. The calibration estimates the scale factors and alignment angles of the photodiodes, resulting in higher attitude determination accuracy than achieved with the pre-flight calibration parameters. The calibration is implemented with an extended Kalman filter to simultaneously ...

Abstract CAS500-1 (Compact Advanced Satellite 500-1) launched in Mar. 2021 is the first Korean ground observation satellite localizing entire mirror development, especially primary M1. M1 a lightweight concave with diameter of 0.6 m, and it has 3 square bosses at rim for flexure mounting. We present whole development procedure flight model M1, including optomechanical design, fabrication, envir...