This paper summarizes the design and setup of DLR's GNSS scintillation recording device which is installed aboard "Polarstern", the German research icebreaker. From September 2019 to September 2020 the icebreaker drifts with the ice shelf through the Arctic Sea. The paper is concluded by an overview of the data which was recorded until beginning of January 2020.

This work presents an overview of the radio interface of VHF Data Exchange System (VDES), which is currently on its way to become an ITU standard supported by International Association of Marine Aids to Navigation and Lighthouse Authorities. VDES includes the already existing collision avoidance tracking system Automatic Identification System and the messaging system Application Specific Messages. Additionally, a new third component for digital maritime communications of any kind, named VHF Data Exchange is included. On the one hand, there is a traditional terrestrial component, on the other hand, a satellite communication link is also envisioned partly by the same spectrum usage. In this article, focus is given towards the technical design aspects and challenges of this hybrid communications transmission scheme.

The possibility to detect Automatic Identification System (AIS) messages from low earth orbit (LEO) satellites paves the road for a plurality of new and unexplored services. Besides worldwide tracking of vessels, maritime traffic monitoring, analysis of vessel routes employing big data, and oceans monitoring are just few of the fields, where satellite-aided AIS is beneficial. Designed for ship-to-ship communication and collision avoidance, AIS satellite reception performs poorly in regions with a high density of vessels. This calls for the development of advanced satellite AIS receivers able to improve the decoding capabilities. In this context, our contribution focuses on the introduction of a new enhanced AIS receiver design and its performance evaluation. The enhanced receiver makes use of a coherent receiver for the low signal-to-noise ratio (SNR) region, while for medium to high SNRs, a differential Viterbi receiver is used. Additional novelty of our work is in the exploitation of previously decoded packets from one vessel that is still under the LEO reception range, to improve the vessel detection probability. The assessment of the performance against a common receiver is done making the use of a simple and tight model of the medium access (MAC) layer and the multi-packet reception (MPR) matrix for physical layer (PHY) representation. Performance results show the benefits of such enhanced receiver, especially when it is bundled with successive interference cancellation (SIC).

Communication Technologies for Vehicles : 10th International Workshop, Nets4Cars/Nets4Trains/Nets4Aircraft 2016, San Sebastian, Spain, June 6-7, 2016, Proceedings

Towards the overall concept of e-navigation by the International Maritime Organization (IMO), one key element is a new communication system, namely VHF Date Exchange System (VDES). VDES consists of the already existing Automatic Identification System (AIS), Application-Specific Messaging (ASM) and the new to be developed VHF Data Exchange (VDE) link. Currently, an international standard is being developed by the International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA) and the International Telecommunication Union (ITU). The maritime community recognizes the concept of VDES as an answer to the following problems: During the last decade the usage of AIS increased and the AIS capacities are highly stressed. Furthermore, new applications are planned to be introduced to the maritime world such as Maritime Safety Information (MSI) services, vessel shore reporting, real-time hydrographic and environmental information services and ice navigation services. These services also increase the appetite for bandwidth. Currently, the definition of Global Maritime Distress and Safety System (GMDSS) is more than 25 years old and is under way of being revised including new emerging needs. Additionally, communication capacities are not globally available. The Polar Regions are cut off from geostationary satellite data pipelines. There is only a minor terrestrial and satellite communications infrastructure existing, which is contrary to increasing activities (mining, cargo, tourism) due to climate change in these challenging areas. The VDE link is part of VDES. This link contains a terrestrial component (VDE-TER) and a satellite component (VDE-SAT). Therefore, VDE will have a global coverage including bidirectional communication capabilities. Within this paper, current results towards the design of the physical layer for VDE-TER and VDE-SAT will be investigated.

Recently, satellite-aided automatic identification system (AIS) has opened new possibilities to the maritime world. Techniques able to capture the AIS traffic behavior at the satellite are of upmost importance for guiding the design of future maritime communication system integrating AIS and new services that can enhance the safety and awareness during navigation. In this context, our contribution focuses on the medium access (MAC) and system levels performance investigation of a common satellite AIS receiver, compared to an advanced one. We present a generic method, capable of evaluating any AIS receiver, making the use of a simplified yet tight model of the MAC layer and the multi-packet reception (MPR) matrix for physical layer (PHY) representation. Performance in terms of both throughput and first pass ship detection probability, show the benefits of such advanced receiver, especially when it is bundled with advanced signal processing capabilities as successive interference cancellation (SIC).

This article surveys the unsatisfying communication capabilities in the harsh Arctic regions. By melting of the ice caps, the undergoing change of the north polar area opens new opportunities and, therefore, increases the need for human and machine-to-machine communications. The emerging demands and challenges are reviewed. New satellite systems, architectures, and technologies being deemed as key enablers are highlighted. As also addressed in this article, satellite links could additionally backhaul terrestrial networks for local communications.

Demands on security, safety, and environmental protection in worldwide shipping are steadily increasing. Shipboard broadcast transponders based on the Automatic Identification System (AIS) can be easily detected close to coastal or waterway areas. Satellite-based AIS receivers detect globally but are limited in high-density traffic areas. This paper investigates the challenges and performance of AIS detection on aircraft at altitudes between 8 500 m and 10 000 m. During flight trials over sea and land, AIS signals were recorded. Post-processing of the recorded data allows the evaluation but also faces challenges due to the nature of overlapping AIS signals at the aircraft. A comparison of detected signals at the aircraft with received AIS signals on the ground is given, including the evaluation of the reception footprint of the aircraft. Finally, a concept for worldwide AIS detection via airliners is presented. The study shows the potential for global complementary surveillance coverage via airliner-based AIS detection.

Automatic Identification System (AIS) reception at flying platforms (satellites or airliners) has attracted an increasing level of attention over the last years. AIS allows vessels to communicate with each other and was originally designed as a vessel collision avoidance mechanism. Although AIS was not designed taking into account a satellite component, it is possible to receive AIS packets using satellites. However, satellite-aided AIS reception is challenging. Satellites receive AIS messages of all ships within a vast geographical area that usually tend to collide with each other. Consequently, the satellite receiver operates at lower SINR values compared to a conventional AIS receiver in a vessel or base station. In this paper we present an advanced receiver for AIS. This receiver exploits the a priori knowledge that the receiver has on some of the fields of the AIS position reports messages. In some cases this allows the receiver to double the number of training symbols that can be used for channel estimation. This receiver design is particularly suitable for receivers placed on flying platforms but it can also be used in other platforms such as vessels.

In the recent past, an increasing interest has been devoted to the possibility of receiving Automatic Identification System (AIS) messages via Low Earth Orbit (LEO) satellites. While the principle has been demonstrated to be a viable option for monitoring vessel traffic over oceans and vaste land areas, the achievable performance from a communications viewpoint is far from optimal. Recently, it was shown how AIS traffic seen at a satellite can be very accurately modeled resorting to simple random access schemes. Leveraging this result, in this work we propose a simple yet flexible analytical framework capable of predicting channel load and overall reception performance taking into account the spatial distribution of vessels as well as their traffic generation pattern. Feeding the model with ship speed and location data derived from experimental settings, we discuss the achievable efficiency for a typical LEO-satellite detecting AIS packets. Moreover, the impact of the receiver footprint on ground on the overall decoding performance is investigated, deriving some interesting insights on the benefits that could stem resorting to narrower-beam systems. In this direction, we discuss two cases: the usage of a LEO satellite with a directional antenna soon to be launched for AIS monitoring, and the possibility of using airliner for receiving vessel-generated traffic.

A method for providing data from the received AIS data packets (1, 2, 3, 4, 5, 6), wherein by means of at least one AIS receiving means (80) AIS data packets (1, 2, 3, 4, 5, 6) received and the data of the received AIS data packets (1, 2, 3, 4, 5, 6) are automatically evaluated, in which the values ​​of some bits of a received AIS data packet (1, 2, 3, 4, 5, 6) based befindlicher of the access of the AIS-receiving means (80) auxiliary data (126) that do not originate from AIS data packets are determined or estimated, and based on this determined or estimated values ​​of the data bits, such data of an AIS data packet (1, 2, 3, 4, 5, 6) that are in error can be reconstructed at least in part, characterized in that the AIS-receiving means (80) at least two operation states (110, 111) in which it is operated, alternatively, said operating states (110 , 111) comprise at least: a) a general knowledge of state (110), in which an evaluation of the received AIS data packets (1, 2, 3, 4, 5, 6) without taking into account stored data previously received AIS data packets (1, 2, 3, 4, 5, 6) takes place, and b) a Vorkenntniszustand (111), in which an evaluation of the received AIS data packets (1, 2, 3, 4, 5, 6), taking account of data stored as knowledge data previously received AIS data packets (1, 2, 3, 4 , 5, 6) is carried out to reconstruct erroneous data received AIS data packets on the basis of such knowledge (127) at least partially.

During flight trials over sea and land, AIS signals were recorded by an aircraft in flight level 280 up to 330, which represents the higher altitudes between 8500m and 10000m. These stored data were post-processed and analyzed. Within this paper, the approach of data's post-processing is described, the experienced characteristics to be handled, and challenges faced by the nature of overlapping AIS signals at the aircraft are highlighted. Finally, a comparison of detected signals at the aircraft with received AIS signals on-ground is given including the evaluation of the reception footprint of the aircraft in different altitudes. This gives insight in the detection probability by using aircraft in high altitudes for AIS signal detection.

This article presents the in-flight demonstration of a new integrated aircraft communications system combining legacy and future radio technologies. This system, developed and validated under real environmental conditions during flight trials, integrates all the aeronautical service domains within a common IPv6-based aeronautical network. The flight trials were held within the framework of the European SANDRA project at Oberpfaffenhofen, Germany, in June 2013. The presented outcomes emphasize the flexibility and scalability of the developed network and demonstrate the seamless service coverage of the given architecture across different airspace domains.(1)

Demands on security, safety, and environmental protection in worldwide shipping is steadily increasing. Shipboard broadcast transponders based on the automatic identification system (AIS) can be easily detected close to coast or waterway areas. Satellite-based AIS receivers detect globally but are limited in high density traffic areas. In this paper, a new possibility for worldwide AIS detection via airliners is presented. A first study is given towards the potential coverage of an airliner-based AIS detection. The usage of airliners as a complementary surveillance infrastructure for detecting AIS signals enables a comprehensive ship detection infrastructure for the future.

The Aeronautical Mobile Airport Communications System (AeroMACS) has been developed for future high-rate, secure, and safety enhancing airport communications in the C-band. Although initially designed for ground applications, the relatively large radio coverage area of AeroMACS suggests its potential extension to new operative scenarios wherein a data link is established between the control tower and the aircraft even when the latter is not in contact with the airport surface. An examination is needed for these new applications concerning channel properties, synchronization aspects, and general performance behaviors. In this paper, the possibility of using AeroMACS during the approach, landing, and takeoff phases of an aircraft flight is investigated. After deriving the channel parameters for the new application scenarios, the synchronization and channel estimation algorithms are presented and the overall error rate performance is assessed by means of computer simulations. Our results indicate that AeroMACS is able to cope with the new operational phases and its use can be extended beyond airport surface applications.

It is tricky to predict the future, especially in the maritime communications market – what are the future demands? Which technologies will be available? How will the regulatory bodies think in the future? Within this paper, the recent development towards future satellite requirements and technologies will be spotlighted. Four use case scenarios are in the focus here, namely: e-navigation, Arctic communications, autonomous ships, and evolution of GMDSS.

ABSTRACT Within this article, a new concept for machine‐to‐machine communications infrastructure via airliners is presented. The main principles and resulting challenges are described, together with a first study on possible coverage within Europe and North America using airliners that endorses the concept's feasibility. Accurate insights are drawn by taking into account all commercial flights during 24 h on the basis of real global flight data. We strengthen the proposed solution by investigating system dimension aspects in a proof‐of‐principle manner as well as by discussing medium access policies and coding strategies capable of achieving performance improvements over alternative architectures. The goal of the article is to stimulate further research activities and ideas in this area. Copyright © 2013 John Wiley & Sons, Ltd.

A new integrated aircraft communications system combining legacy and future technologies has been designed, developed and validated under real environment conditions within the framework of the EU FP7 SANDRA project. With IPv6 as unification point, this system integrates all the aeronautical service domains within a common IP-based aeronautical network as well as with legacy and non-legacy radio technologies. This paper presents the flight trial outcomes of the SANDRA system that occurred in the vicinity of the German Aerospace Center (DLR) in Oberpfaffenhofen, Germany in June 2013. The presented results will emphasize the flexibility and scalability of the SANDRA network and demonstrate the seamless service coverage of the SANDRA architecture across different airspace domains.