On Small Satellites for Oceanography: A Survey

The recent explosive growth of small satellite operations driven primarily from an academic or pedagogical need, has demonstrated the viability of commercial-off-the-shelf technologies in space. They have also leveraged and shown the need for development of compatible sensors primarily aimed for Earth observation tasks including monitoring terrestrial domains, communications and engineering tests. However, one domain that these platforms have not yet made substantial inroads into, is in the ocean sciences. Remote sensing has long been within the repertoire of tools for oceanographers to study dynamic large scale physical phenomena, such as gyres and fronts, bio-geochemical process transport, primary productivity and process studies in the coastal ocean. We argue that the time has come for micro and nano satellites (with mass smaller than 100 kg and 2 to 3 year development times) designed, built, tested and flown by academic departments, for coordinated observations with robotic assets in situ. We do so primarily by surveying SmallSat missions oriented towards ocean observations in the recent past, and in doing so, we update the current knowledge about what is feasible in the rapidly evolving field of platforms and sensors for this domain. We conclude by proposing a set of candidate ocean observing missions with an emphasis on radar-based observations, with a focus on Synthetic Aperture Radar.Comment: 63 pages, 4 figures, 8 table

Space-based Global Maritime Surveillance. Part I: Satellite Technologies

Maritime surveillance (MS) is crucial for search and rescue operations, fishery monitoring, pollution control, law enforcement, migration monitoring, and national security policies. Since the early days of seafaring, MS has been a critical task for providing security in human coexistence. Several generations of sensors providing detailed maritime information have become available for large offshore areas in real time: maritime radar sensors in the 1950s and the automatic identification system (AIS) in the 1990s among them. However, ground-based maritime radars and AIS data do not always provide a comprehensive and seamless coverage of the entire maritime space. Therefore, the exploitation of space-based sensor technologies installed on satellites orbiting around the Earth, such as satellite AIS data, synthetic aperture radar, optical sensors, and global navigation satellite systems reflectometry, becomes crucial for MS and to complement the existing terrestrial technologies. In the first part of this work, we provide an overview of the main available space-based sensors technologies and present the advantages and limitations of each technology in the scope of MS. The second part, related to artificial intelligence, signal processing and data fusion techniques, is provided in a companion paper, titled: "Space-based Global Maritime Surveillance. Part II: Artificial Intelligence and Data Fusion Techniques" [1].Comment: This paper has been submitted to IEEE Aerospace and Electronic Systems Magazin

Space Remote Sensing and Detecting Systems of Oceangoing Ships

This paper introduces the implementation of space remote sensing and detecting systems of oceangoing ships as an alternative to the Radio – Automatic Identification System (R-AIS), Satellite – Automatic Identification System (S-AIS), Long Range Identification and Tracking (LRIT), and other current vessel tracking systems. In this paper will be not included  a new project known as a Global Ship Tracking (GST) as an autonomous and discrete satellite network designed by the Space Science Centre (SSC) for research and postgraduate studies in Satellite Communication, Navigation and Surveillance (CNS) at Durban University of Technology (DUT). The ship detection from satellite remote sensing imagery system is a crucial application for maritime safety and security, which includes among others ship tracking, detecting and traffic surveillance, oil spill detection service, and discharge control, sea pollution monitoring, sea ice monitoring service, and protection against illegal fisheries activities. The establishment of a modern sea surface and ships monitoring system needs enhancement of the Satellite Synthetic Aperture Radar (SSAR) that is here discussed as a modern observation infrastructure integrated with Ships Surveillance and Detecting via SSAR TerraSAR-X Spacecraft, Ships Surveillance and Detecting via SSAR Radarsat Spacecraft and Vessels Detecting System (VDS) via SSAR

Designing a constellation for AIS mission based on data acquisition of LAPAN-A2 and LAPAN-A3 satellites

Indonesia requires a maritime surveillance system that's capable to monitor its extensive waters territorial. One of the maritime standard navigation systems named AIS (Automatic Identification System), which is based on GPS and VHF digital communication, have enabled the ship monitoring in a real-time. By placing AIS receiver on the satellite, its coverage will be larger compared to the one usually placed on the seashore by maritime authority. Orbiting the AIS receiver prompted appearing the limitation of Time Division Multiple Access (TDMA) technology so the probability of ship detection would decrease drastically due to a huge number of heard ship signal simultaneously. This paper describes the design of satellite constellation for Indonesian maritime surveillance based on the result of the AIS data acquisition by LAPAN-A2 and LAPAN-A3 satellites that operate in both equatorial and polar orbit

Study and design of a Business Model that explore the complementarity of VLEO platforms for Vessel Tracking

Throughout this study, the application of satellites in a Very Low Earth Orbit (VLEO) is analyzed to complement the already existing technologies used for vessels tracking. This study is part of the DISCOVERER project, which focuses on the research and development of VLEO technologies to apply them in Earth Observation (EO). Within the team, the UPC focuses on market analysis and the study of business opportunities for VLEO technologies. A value proposition is developed following the Canvas model, this being the strategy used to offer a service to a specific client. For the development of the value proposition, the study focuses on optimizing vessels tracking for maritime transport companies. A market study is carried out previously, to analyse how could the value proposition fit in it. The analysis determines that the optimal methodology and technologies to complement the platforms currently used for vessels tracking with an AIS system (Automatic Identification System) installed, is through Data Integration. This method refers to the combination of the data obtained by different platforms (satellites with different technologies and in different orbits complementing both, aerial and terrestrial platforms) once received in the ground station. For the tracking of those ships exempt from carrying an AIS transponder or those that do not want to be tracked, the optimal tracking method would be the combination of data between different platforms before being received on the ground station (System Integration)

Sea target detection using spaceborne GNSS-R delay-doppler maps: theory and experimental proof of concept using TDS-1 data

© 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This study addresses a novel application of global navigation satellite system-reflectometry (GNSS-R) delay-Doppler maps (DDMs), namely sea target detection. In contrast with other competing remote sensing technologies, such as synthetic aperture radar and optical systems, typically exploited in the field of sea target detection, GNSS-R systems could be employed as satellite constellations, so as to fulfill the temporal requirements for near real-time ships and sea ice sheets monitoring. In this study, the revisit time offered by GNSS-R systems is quantitatively evaluated by means of a simulation analysis, in which three different realistic GNSS-R missions are simulated and analyzed. Then, a sea target detection algorithm from spaceborne GNSS-R DDMs is described and assessed. The algorithm is based on a sea clutter compensation step and uses an adaptive threshold to take into account spatial variations in the sea background and/or noise statistics. Finally, the sea target detector algorithm is tested and validated for the first time ever using experimental GNSS-R data from the U.K. TechDemoSat-1 dataset. Performance is assessed by providing the receiver operating characteristic curves, and some preliminary experimental results are presented.Peer ReviewedPostprint (published version

Implementation of African Satellite Augmentation System (ASAS) for Maritime Applications

This paper introduces implementation of the new project known as African Satellite Augmentation System (ASAS) for Africa and Middle East, designed by the CNS Systems Company and its research group supported by partners. The ASAS project as Regional Satellite Augmentation Systems (RSAS) will provide service for maritime, land (road and rail), and aeronautical applications. Thus, with existing and other newly designed RSAS networks, it will be integrated in Global Satellite Augmentation System (GSAS) with new Satellite Communication, Navigation and Surveillance (CNS) for improved Ship Traffic Control (STC) and Ship Traffic Management (STM). This System also enhances safety and emergency systems, transport security and control of ocean shipping freight, logistics and the security of the crew and passengers onboard ships and fishing vessels as well. The current CNS infrastructures of the first generation of Global Navigation Satellite System (GNSS-1) applications are represented by old fundamental solutions for Position, Velocity, and Time (PVT) of the satellite navigation and determination systems, such as the US GPS and Russian (former USSR) GLONASS military requirements, respectively. The establishment of Space, Ground, and User segment, including Local Satellite Augmentation System (LSAS), are discussed as a new basic infrastructures for maritime and other mobile applications, which will be integrated with RSAS in the future GSAS network

Europe's Space capabilities for the benefit of the Arctic

In recent years, the Arctic region has acquired an increasing environmental, social, economic and strategic importance. The Arctic’s fragile environment is both a direct and key indicator of the climate change and requires specific mitigation and adaptation actions. The EU has a clear strategic interest in playing a key role and is actively responding to the impacts of climate change safeguarding the Arctic’s fragile ecosystem, ensuring a sustainable development, particularly in the European part of the Arctic. The European Commission’s Joint Research Centre has recently completed a study aimed at identifying the capabilities and relevant synergies across the four domains of the EU Space Programme: earth observation, satellite navigation, satellite communications, and space situational awareness (SSA). These synergies are expected to be key enablers of new services that will have a high societal impact in the region, which could be developed in a more cost-efficient and rapid manner. Similarly, synergies will also help exploit to its full extent operational services that are already deployed in the Arctic (e.g., the Copernicus emergency service or the Galileo Search and rescue service could greatly benefit from improved satellite communications connectivity in the region).JRC.E.2-Technology Innovation in Securit

Experimental demonstration of ship target detection in GNSS-based passive radar combining target motion compensation and track-before-detect strategies

This work discusses methods and experimental results on passive radar detection of moving ships using navigation satellites as transmitters of opportunity. The reported study highlights as the adoption of proper strategies combining target motion compensation and track-before-detect methods to achieve long time integration can be fruitfully exploited in GNSS-based passive radar for the detection of maritime targets. The proposed detection strategy reduces the sensitivity of long-time integration methods to the adopted motion models and can save the computational complexity, making it appealing for real-time implementations. Experimental results obtained in three different scenarios (port operations, navigation in open area, and river shipping) comprising maritime targets belonging to different classes show as this combined approach can be employed with success in several operative scenarios of practical interest for this technology