Spacecraft in low-Earth orbit are exposed to environmental threats which can lead material degradation and component failures. The presence of atomic oxygen collisions from orbital debris have detrimental effects on the structures, thus affecting their performance. Cranfield University has developed a family drag augmentation systems (DAS), for end-of-life de-orbit satellites, addressing space ...

Limiting factors for the precise orbit determination POD of low-earth orbit LEO satellite using dual-frequency GPS are nowadays mainly encountered with the in-flight phase error modeling. The phase error is modeled as a systematic and a random component each depending on the direction of GPS signal reception. The systematic part and standard deviation of random part in phase error model are, re...

A control system is proposed for a low Earth orbit gravity gradient stabilised microsatellite using Z wheel. The microsatellite is 3-axis stabilized using a yaw reaction wheel, with dual redundant 3-axis magnetorquers. Two vector magnetometers and four dual sun sensors are carried in order to determine the full attitude. The attitude was estimated using an Euler angles (small libration version)...

We present an analytical model for computing call-blocking probabilities in a low earth orbit (LEO) satellite network that carries voice calls. Both satelliteand earth-fixed constellations with interorbit links and handoffs are considered. In this model, we assume a single beam per satellite. Also, we assume that call arrivals are Poisson with a fixed arrival rate that is independent of the geo...

In this paper, we use differential evolution (DE), with best-evolved results refined using a Nelder–Mead optimization, to solve boundary-value complex problems in orbital mechanics relevant to low Earth orbits (LEO). A class of Lambert-type problems is examined to evaluate the performance of this evolutionary method in its application to solving nonlinear boundary value problems (BVP) arising i...

This paper provides an updated efficiency analysis of the LightForce space debris collision avoidance scheme. LightForce aims to prevent collisions on warning by utilizing photon pressure from ground based, commercial off the shelf lasers. Past research has shown that a few ground-based systems consisting of 10 kW class lasers directed by 1.5 m telescopes with adaptive optics could lower the ex...

Along with the deployment of low earth orbit (LEO) satellite constellations for global Internet services, Ku, Ka or V band microwave signals will be available from space anywhere on Earth. Utilizing signals, a new approach to positioning flying objects passively is proposed, and diffraction model characterize impact object intensity received presented. A linear Minimum Mean Squared Error (MMSE)...

Several analytical and numerical methods exist to solve the orbit propagation of the two-body problem. Analytic solutions are mainly implemented for the unperturbed/classical two-body problem. Numerical methods can handle both the unperturbed and the perturbed two-body problem. The literature is rich with numerical methods addressing orbit propagation problems such as, Gauss-Jackson, Higher ord...

Low Earth orbit (LEO) satellite plays an indispensable role in the equal access network because of its low latency, large capacity, and seamless global coverage. For such unprecedented extensive irregular system, stochastic geometry (SG) is a suitable research method. The SG model can not only cope with increasing scale, but also accurately analyze estimate network's performance. Several standa...

Mobility management is an important aspect in LEO (low earth orbit) systems. In terrestrial wireless networks, the movement of the user triggers location updating and determines the paging scheme, while in LEO satellite systems, the location updating and paging is mainly based on the movement of satellite. Terrestrial location management techniques must be altered to fit the LEO systems. This p...