Hybrid Satellite-Terrestrial Communication Networks for the Maritime Internet of Things: Key Technologies, Opportunities, and Challenges

With the rapid development of marine activities, there has been an increasing number of maritime mobile terminals, as well as a growing demand for high-speed and ultra-reliable maritime communications to keep them connected. Traditionally, the maritime Internet of Things (IoT) is enabled by maritime satellites. However, satellites are seriously restricted by their high latency and relatively low data rate. As an alternative, shore & island-based base stations (BSs) can be built to extend the coverage of terrestrial networks using fourth-generation (4G), fifth-generation (5G), and beyond 5G services. Unmanned aerial vehicles can also be exploited to serve as aerial maritime BSs. Despite of all these approaches, there are still open issues for an efficient maritime communication network (MCN). For example, due to the complicated electromagnetic propagation environment, the limited geometrically available BS sites, and rigorous service demands from mission-critical applications, conventional communication and networking theories and methods should be tailored for maritime scenarios. Towards this end, we provide a survey on the demand for maritime communications, the state-of-the-art MCNs, and key technologies for enhancing transmission efficiency, extending network coverage, and provisioning maritime-specific services. Future challenges in developing an environment-aware, service-driven, and integrated satellite-air-ground MCN to be smart enough to utilize external auxiliary information, e.g., sea state and atmosphere conditions, are also discussed

Selected Papers from the 2018 IEEE International Workshop on Metrology for the Sea

This Special Issue is devoted to recent developments in instrumentation and measurement techniques applied to the marine field. ¶The sea is the medium that has allowed people to travel from one continent to another using vessels, even today despite the use of aircraft. It has also been acting as a great reservoir and source of food for all living beings. However, for many generations, it served as a landfill for depositing conventional and nuclear wastes, especially in its deep seabeds, and we are assisting in a race to exploit minerals and resources, different from foods, encompassed in it. Its health is a great challenge for the survival of all humanity since it is one of the most important environmental components targeted by global warming. ¶ As everyone may know, measuring is a step that generates substantial knowledge about a phenomenon or an asset, which is the basis for proposing correct solutions and making proper decisions. However, measurements in the sea environment pose unique difficulties and opportunities, which is made clear from the research results presented in this Special Issue

Technical approaches, chapter 3, part E

Radar altimeters, scatterometers, and imaging radar are described in terms of their functions, future developments, constraints, and applications

Policy issues and data communications for NASA earth observation missions until 1985

The series of LANDSAT sensors with the highest potential data rates of the missions were examined. An examination of LANDSAT imagery uses shows that relatively few require transmission of the full resolution data on a repetitive quasi real time basis. Accuracy of global crop size forecasting can possibly be improved through information derived from LANDSAT imagery. A current forecasting experiment uses the imagery for crop area estimation only, yield being derived from other data sources

Testing the Accuracy of Large-Scale GNSS-R Applications

Global Navigation Satellite System Reflectometry (GNSS-R) is a promising technology with a huge potential. Naming just few most interesting applications, remote sensing of the sea surface roughness and salinity, snow structures, and sea-ice characterization, we can realize the importance of GNSS-R. Due to a variety of possible platforms (satellites, aircrafts, helicopters, etc.) different resolutions are available for the final users, which imply, also, different scopes of the accuracy. In this paper we are testing the resolution and accuracy of a water surface level obtained by GNSS-R. We utilizied a platform set to a pedestrian bridge, with two GNSS receivers. One of them is attached to the upper side of the platform, while the other is placed upside-down, directing to the water mirror. The upper GNSS will receive only the direct signals from the satellites, while the latter one will create its position only according to the „false“ measurements, meaning the signals reflected from the water. Knowing the mutual positional relation between the two receivers, we can calculate the height of the water mirror and, after longer measuring sessions, monitor the change of the river level

Altimetric system: Earth observing system. Volume 2h: Panel report

A rationale and recommendations for planning, implementing, and operating an altimetric system aboard the Earth observing system (Eos) spacecraft is provided. In keeping with the recommendations of the Eos Science and Mission Requirements Working Group, a complete altimetric system is defined that is capable of perpetuating the data set to be derived from TOPEX/Poseidon, enabling key scientific questions to be addressed. Since the scientific utility and technical maturity of spaceborne radar altimeters is well documented, the discussion is limited to highlighting those Eos-specific considerations that materially impact upon radar altimetric measurements

Satellite technology in the maritime world : applications and implications

This dissertation is a study of the widespread utilization of satellite technology in the maritime world, with particular reference to the applications and implications of communication, navigation and remote sensing satellites to shipping and other maritime related fields. A brief look is taken at the general background of satellite technology, including the growth and development and basic techniques as well as categorization of applications. This is followed by a more detailed view of the three different areas of the applications of satellite technology, namely maritime communications, marine navigation and maritime meteorology and oceanography. The two well-known satellite-based systems, the INMARSAT System and the Global Positioning System, are both widely used by the maritime community and thus emphasized in this study. Apart from a brief description of those two systems, their applications are examined, their impact on the marine industry is discussed and their future development is investigated in order to obtain an appreciation of their role in the present maritime world. The applications of remote sensing satellites in marine meteorology and oceanography are also discussed. In addition to the above, the impact of the increasing use of satellite technology on maritime education and training is investigated. The concluding chapter is a summary of the main points discussed in the core chapters, which reflect the author’s viewpoin

New methods and applications for interferometric GNSS reflectometry

The GNSS reflectometry technique has been proven to be usable for measuring several environmental properties, such as soil moisture, snow depth, vegetation, and sea level.\ua0As numerous GNSS installations are already installed around the world for geodetic purposes, the technique opens up a large data set for new analyses, complementing other environmental measurement campaigns.\ua0However, a main drawback of the technique is that its precision generally is worse than more specialised equipment, and while this is in part compensated for its low cost and maintenance requirements, improved precision is still a main goal of research in the field of GNSS reflectometry.The first topic of this thesis concerns the development of new methods for analysing GNSS-R data to retrieve precise measurements, especially in the case of sea level.As GNSS-R measurements are usually done over time spans of around half an hour, the dynamic sea surface has proven to be a challenge to measure.\ua0However, using inverse modelling with least squares adjustment, we prove that we can significantly improve the retrieval precision.\ua0Developing on the inverse modelling approach, we also prove that high-precision real-time GNSS reflectometry is also feasible using Kalman filtering.The other main topic of this thesis is finding new applications for the GNSS-R technique.\ua0Firstly, we show that when a GNSS-R installation is mounted close to a body of water, it is possible to determine whether the surface is frozen or not.\ua0Secondly, while GNSS reflectometry is traditionally performed with high-precision geodetic instruments, we show that everyday devices, such as a mobile phone, can be used instead.\ua0\ua0We find that the precision of the mobile devices is on a similar level as for geodetic equipment.Finally, this thesis explores and highlights one of the challenges that are still left in GNSS-R research: absolute referencing of sea level measurements.\ua0Past research has mostly focused on precision, leaving out accuracy, and we show that there are unknown effects that cause an offset between GNSS-R measurements and co-located tide gauges

Applications of a High-Altitude Powered Platform (HAPP)

A list of potential uses for the (HAPP) and conceptual system designs for a small subset of the most promising applications were investigated. The method was to postulate a scenario for each application specifying a user, a set of system requirements and the most likely competitor among conventional aircraft and satellite systems. As part of the study of remote sensing applications, a parametric cost comparison was done between aircraft and HAPPS. For most remote sensing applications, aircraft can supply the same data as HAPPs at substantially lower cost. The critical parameters in determining the relative costs of the two systems are the sensor field of view and the required frequency of the observations being made. The HAPP is only competitive with an airplane when sensors having a very wide field of view are appropriate and when the phenomenon being observed must be viewed at least once per day. This eliminates the majority of remote sensing applications from any further consideration