Satellite Technology

In recent years we have seen a growth in the revenues and investments of satellite industry. Originally, satellites, remote sensing (RS), and other navigations systems were only employed for government and military purposes. However, in the past two decades there has been an increase use of these tools for commercial purposes. In particular, satellites and RS can be used for space and earth observations, support military operations, precision agriculture, meteorological forecasting, communication and internet connectivity to lesser-known applications such as in transport tracking and monitoring of utility networks. In this paper, we analyse the current trends, benefits and limitations of the use of satellites and RS. In particular, we try to identify the main socio-economic benefits deriving from the use of RS in several sectors. We also seek to introduce economists to the science of RS data, and give a flavour of how this new fountain of data can be utilized so far and what might be done in the future.

Nigeria as a nation experienced flooding incidents that claims many lives render many homeless and also disrupts environmental and socioeconomic activities in recent times. With the 2012 flood, causing a devastating effect on the country especially states along the rivers Niger and Benue with huge destruction to the rural and urban infrastructure. In a way to mitigate the extent of damage and casualties during a flood disaster, the study is aimed at promoting the use of Nigerian Satellites in flood disaster preparedness, and response for emergency management. The study also identifies the stakeholders in disaster and emergency management to collaborate with the National Space Research and Development Agency (NASRDA) and National Emergency Management Agency (NEMA) towards attaining a sustainable disaster risk management in Nigeria, and adopt a conceptual framework for improving flood disaster preparedness and response in emergency management using Nigerian Satellite data and other ancillary data. The approach employed was a combination of satellite imagery, imagery intelligence and geospatial information with the help of Information Communication Technology to plan ahead for any flood event during the pre-disaster phase. The incorporation of geospatial techniques using the Nigerian earth observation and communication satellites in flood disaster and emergency management will help emergency relief distribution and budget planning for any flood disaster provided there is synergy, commitment and information sharing among stakeholders.

The aim of this report is to design and implement in Simulink the attitude determination and control system of a 6U CubeSat orbiting around the Earth in LEO environment and subjected to orbital perturbations of magnetic field, SRP, gravity gradient and atmospheric drag.
The mission is to detumble it and then point it towards the Sun.

This paper presents the system's architecture, the description of the adopted model, the
analysis of the control algorithms used and all the results obtained.

In an era of significant air traffic expansion characterised by a rising congestion of the radiofrequency spectrum and a widespread introduction of Unmanned Aircraft Systems (UAS), Global Navigation Satellite Systems (GNSS) are being exposed to a variety of threats including signal interferences, adverse propagation effects and challenging platform-satellite relative dynamics. Thus, there is a need to characterize GNSS signal degradations and assess the effects of interfering sources on the performance of avionics GNSS receivers and augmentation systems used for an increasing number of mission-essential and safety-critical aviation tasks (e.g., experimental flight testing, flight inspection/certification of ground-based radio navigation aids, wide area navigation and precision approach). GNSS signal deteriorations typically occur due to antenna obscuration caused by natural and man-made obstructions present in the environment (e.g., elevated terrain and tall buildings when flying at low altitude) or by the aircraft itself during manoeuvring (e.g., aircraft wings and empennage masking the on-board GNSS antenna), ionospheric scintillation, Doppler shift, multipath, jamming and spurious satellite transmissions. Anyone of these phenomena can result in partial to total loss of tracking and possible tracking errors, depending on the severity of the effect and the receiver characteristics. After describing GNSS performance threats, the various augmentation strategies adopted in the Communication, Navigation, Surveillance/Air Traffic Management and Avionics (CNS+A) context are addressed in detail. GNSS augmentation can take many forms but all strategies share the same fundamental principle of providing supplementary information whose objective is improving the performance and/or trustworthiness of the system. Hence it is of paramount importance to consider the synergies offered by different augmentation strategies including Space Based Augmentation System (SBAS), Ground Based Augmentation System (GBAS), Aircraft Based Augmentation System (ABAS) and Receiver Autonomous Integrity Monitoring (RAIM). Furthermore, by employing multi-GNSS constellations and multi-sensor data fusion techniques, improvements in availability and continuity can be obtained. SBAS is designed to improve GNSS system integrity and accuracy for aircraft navigation and landing, while an alternative approach to GNSS augmentation is to transmit integrity and differential correction messages from ground-based augmentation systems (GBAS). In addition to existing space and ground based augmentation systems, GNSS augmentation may take the form of additional information being provided by other on-board avionics systems, such as in ABAS. As these on-board systems normally operate via separate principles than GNSS, they are not subject to the same sources of error or interference. Using suitable data link and data processing technologies on the ground, a certified ABAS capability could be a core element of a future GNSS Space-Ground-Aircraft Augmentation Network (SGAAN). Although current augmentation systems can provide significant improvement of GNSS navigation performance, a properly designed and flight-certified SGAAN could play a key role in trusted autonomous system and cyber-physical system applications such as UAS Sense-and-Avoid (SAA).