Terrestrial Technology Research Articles

Discussion of “Evaluation of Terrestrial and Mobile Scanner Technologies for Part-Built Information Modeling” by Samad M. E. Sepasgozar, Perry Forsythe, and Sara Shirowzhan

Discussion of “Evaluation of Terrestrial and Mobile Scanner Technologies for Part-Built Information Modeling” by Samad M. E. Sepasgozar, Perry Forsythe, and Sara Shirowzhan

Microlensing and photon bunching: the impact of decoherence

ABSTRACT Gravitational microlensing within the Galaxy offers the prospect of probing the details of distant stellar sources, as well as revealing the distribution of compact (and potentially non-luminous) masses along the line of sight. Recently, it has been suggested that additional constraints on the lensing properties can be determined through the measurement of the time delay between images through the correlation of the bunching of photon arrival times; an application of the Hanbury–Brown Twiss effect. In this paper, we revisit this analysis, examining the impact of decoherence of the radiation from a spatially extended source along the multiple paths to an observer. The result is that, for physically reasonable situations, such decoherence completely erases any correlation that could otherwise be used to measure the gravitational lensing time delay. Indeed, the divergent light paths traverse extremely long effective baselines at the lens plane, corresponding to extremes of angular resolving power well beyond those attainable with any terrestrial technologies; the drawback being that few conceivable celestial objects would be sufficiently compact with high enough surface brightness to yield usable signals.

IDMS Solution for Hybrid Broadcast Broadband Delivery Within the Context of HbbTV Standard

Inter-destination media synchronization (IDMS) is a key requirement to enable successful networked shared media experiences between remote users. This paper presents an adaptive, accurate and standard-compliant IDMS solution for hybrid broadcast and broadband delivery. Apart from providing multi- and cross-technology support, the presented IDMS solution is able to accomplish synchronization when different formats/versions of the same, or even related, contents are being played out in a shared session. It is also able to independently manage the playout processes of different groups of users. The IDMS solution has been integrated within an end-to-end platform, which is compatible with the hybrid broadcast broadband TV standard. It has been applied to digital video broadcasting—terrestrial technology and tested for a Social TV scenario, by also including an ad-hoc chat tool as an interaction channel. The results of the conducted (objective and subjective) evaluations prove the statisfactory behavior and performance of the IDMS solution and platform as well as in terms of the perceived quality of experience.

Near Real-time S-AIS

The Automatic identification System (AIS) has been mainly designed to improve safety and efficiency of navigation, environmental protection, coastal traffic monitoring simplifying identification and communication. Additionally, historical AIS data have been used in many other areas of maritime safety, economic and environmental research. The probability of the detection of terrestrial AIS signals from space was presented in 2003, following the advancements in micro satellite technology. Through constant development, research and cooperation between governmental and private sectors, Satellite AIS (S-AIS) has been continuously evolving. Advancements in signal and data processing techniques have resulted in an improved detection over vast areas outside of terrestrial range. Some of the challenges of S-AIS technology include satellite revisit times, message collision and ship detection probability. Data processing latency and lacking the continuous real-time coverage made it less reliable for end user in certain aspects of monitoring and data analysis. Recent developments and improvements by leading S-AIS service providers have reduced latency issues. Complementing with terrestrial AIS and other technologies, near real-time S-AIS can further enhance all areas of the global maritime monitoring domain with emerging possibilities for maritime industry.

Context‐aware hybrid satellite‐terrestrial broadband access

SummaryOne of the key performance targets on the European Commission's Digital Agenda is to provide at least 30‐Mbit/s broadband coverage to all European households by 2020. The deployment of existing terrestrial technologies will not be able to satisfy the requirements in the most difficult‐to‐serve locations, either due to a lack of coverage in areas where the revenue potential for terrestrial service providers is too low or due to technological limitations that diminish the available throughput in rural environments. In this paper, we investigate a hybrid broadband system combining satellite and terrestrial access networks. The system design and the key building blocks of the intelligent routing entities (referred to as intelligent gateways) are presented. To justify the hybrid broadband system's performance subjectively, lab trials have been performed with an integrated multiple access network emulator and a variety of typical multimedia applications that have varying requirements. The results of the lab trials suggest that the quality of experience is consistently improved thanks to the utilisation of intelligent gateway devices, when compared with using a single access network at a time.

Radiation-hardening and testing approach for bringing a terrestrial RF transceiver to the space environment

Present-day space-qualified component performance and flexibility is limited when compared to the capabilities of electronic parts for terrestrial applications. While some component manufacturers provide ranges of products that are radiation-hardened and radiation-tolerant, their computational performances are sometimes limited. In other cases, it is even impossible to find high reliability parts that match the required functionality, such as, for instance, radio-frequency components for a highly-dynamic software-defined radio platform. In fact, when talking about communications, terrestrial technologies are far more advanced than those applied in space. Motivated by the global mobile communications market, permanently seeking new products and development areas, these technologies experience an unparalleled evolution. Then, how can Space benefit from these technological advances on Ground, without sacrificing reliability?Such challenge was faced in the development of an Inter-Satellite Link (ISL) for the ESA Proba-3 formation flying mission. The baseline technology was based on a terrestrial software-defined transceiver architecture, relying on state-of-the-art electronic parts. For this reason, and to avoid a major redesign of the ISL data link, the approach selected to handle radiation in the ISL units was threefold: (i) Develop a mechanical design that is able to provide considerable shielding to the electronic components inside, through an increase of thickness. The additional mass is compensated by the miniaturisation levels attained by not using bigger and heavier radiation-hardened components; (ii) Implement design techniques that help to mitigate the single-event effects caused by high-energised particles. Techniques include latch-up protection, voting systems on the processors or Triple Modular Redundancy (TMR); and (iii) Perform radiation testing on selected critical components or assemblies, against the Proba-3 radiation environment, and devise backup component replacement strategies.This paper describes the approach being followed for the radiation qualification of the Proba-3 ISL unit, based mostly on commercial parts, and the different challenges faced throughout the process. It covers the three levels described before: mechanical shielding, radiation-hardening design techniques and radiation verification testing, including analysis and test results. Additionally, the paper addresses the benefits and technical and economical viability of this integrated strategy to increase the variety of the space-approved parts, in order to enable better-performing satellite missions and bridge the existing gap between space and terrestrial technology.

ACHIEVING MAXIMUM SFN SIZE FOR A DVB-T2 TRANSMISSION SYSTEM

The GE-06 Agreement “On planning the terrestrial digital broadcasting services in parts of Region 1 and 3, in the frequency bands of 174-230 MHz and 470-862 MHz” has been based in the DVB-T system of transmission. Most of the signatory countries of this agreement use or are going to use the most advanced digital terrestrial technology such as DVB-T2. One of the main advantages of DVB-T2 comparing with DVB-T is an increased size of SFN networks, which is closely related with guard interval or inter-transmitters distances. To achieve the maximum size of DVB-T2 SFNs, it is important to find optimal parameters of DVB-T2 networks. But even though the GE-06 Plan gives opportunities to implement DVB-T2 there are some limitations on using all its benefits. One of these limitations is the availability to increase the distance between transmitters because changes in the location of any transmitter require long and intensive coordination with neighboring countries. The aim of this paper is to investigate the optimal DVB-T2 networks configuration for two existing SFN networks in Albania with the purpose to achieve maximum SFN size without adding transmitters or changing the location of existing transmitters.

Solar Power Concentrators for Space Applications

Space based solar power is an attractive solution to growing energy needs, overcoming the operational downtime and atmospheric losses inherent to terrestrial solar technologies. Ideal solar satellites include concentrator systems in order to produce a high specific power output, keeping mass low for economic launch. A meta analysis of photovoltaic concentrator research is presented to determine viability in space applications, considering contributions to cell heating, subcell current matching and efficiency of the InGaP/GaAs/Ge multi-junction cell. We find that the CaF2 Fresnel lens is an optimal choice with an efficiency increase of 4.9% at 17 suns. The large range of concentration ratio, low mass, compact design and minimal effect on spectral irradiance allow a wide space for optimisation in temperature control, whilst the current matching conditions under concentration can be regulated by appropriate tunnel junction width and bandgap.

Measurement, inventory and diagnostics of wooden vernacular architecture - selected issues the use of terrestrial scanning technology

The article aims is to discuss basic issues related to the use of scanning technology, especially laser scanning in the measurement, inventory and diagnostics of wooden vernacular architecture. The article focuses on the following issues: (1) scan of the historic wooden architecture as part of the process of digitization (3D microscopy, scanning arms, structural scan, terrestrial laser scanning ); (2) the challenges and problems; (3) recommendations and guidance in inventory operations using modern measurement technologies.

The impacts of technology: a re-evaluation of the STIRPAT model

The STochastic Impacts by Regression on Population, Affluence and Technology (STIRPAT) model has become a widely employed methodological approach within social science research, largely used to understand the complex relationships between human social systems and the non-human environment. The general assumption of the model is that anthropogenic environmental impacts are a multiplicative function of population, affluence, and technology. While previous STIRPAT research has examined the impact of technology in terms of urbanization, estimating the specific effect of urban population, we argue that this measure is better understood as a proxy for modernization. As an alternative, we frame urbanization as a multidimensional driver of environmental change, and we operationalize the technology dimension through cross-national data on impervious surface area, or what we call ‘terrestrial technology’. To demonstrate the potential of this example for environmental sociology, we draw from political economy to show how operationalizing technology offers a stronger, more nuanced understanding of the socioeconomic drivers of environmental degradation. Analytically, we employ a spatial regression model that estimates the effect of terrestrial technology on total carbon emissions for 173 countries. Our results show that impervious surface area is positively related to total carbon output and thus should be considered an operational measure of technology in future STIRPAT analyses.

Signal processing techniques for anywhere, anytime positioning

In the wide and active research community dealing with positioning techniques, the idea of being able to seamlessly locate a device, regardless of its particular location (indoor, outdoor, in the air, at sea, etc.), has been around for decades. More recently, the value of location-based applications in diverse fields such as homeland security and disaster management, transport, logistics and advertising, and tourism, just to mention a few, has also been widely recognized. We are thus witnessing a blooming of different technologies to eventually help coming to the goal of anywhere, anytime positioning (AAP): the ability of having available at any time the indication of the location of a device anywhere in the world. We could compare and parallel the requirement of this AAP feature and the development of the necessary technology with what has already happened in the field of wireless communications: ubiquitous cellular networks have now successfully come to their fourth generation with LTE-A technologies that are spreading all over the world, and the fifth generation is now being studied in many R&D labs. A similar evolution can be seen in satellite-based positioning, where we may label GPS as the first generation and GALILEO and GPS II as the second, with the third generation being developed right now (in Europe, the GALILEO II Generation project). With respect to wireless communications, positioning is severely lagging behind in terms of standardization efforts: when it comes to terrestrial-based positioning, be it indoor or outdoor, an international agreement on a set of standard techniques to be developed and adopted still has to come. In addition to this, no universal procedure to perform a ‘seamless handover’ between satellite and terrestrial technologies (or in general between two different positioning techniques) has been defined yet, adding further friction against a smooth development of AAP. Curiously, the sole example of a truly universal location procedure that is going to become a de facto standard is

The Use of Statistical Risk Assessment by the FCC in Spectrum Regulation

This paper explores the FCC’s approach to spectrum regulation by examining its quantification of harmful interference, analysis of service rules in its rule-making process, and the content of its final service rules. The paper was developed to support the Interference Studies project of the FCC TAC 2013 Spectrum and Receivers working group. The FCC has traditionally used worst-case analysis to determine whether new service rules will cause interference, and the FCC’s final service rules have traditionally been single-value. However, a worst case-analysis and single-valued rules arguably creates unnecessarily conservative rules that may not result in the maximum benefit to society. Thus, a number of analysts and regulators have argued for statistical approaches to spectrum policy. This paper continues as follows: Section I identifies the FCC’s regulation of interference in the following three contexts: 1. The discussion and definition of harmful interference. 2. The technical analysis of service rules done during the rule-making process. 3. The content of final service rules. In order to better understand the status quo in the FCC’s spectrum policy, Section I examines the three contexts based on the following five distinctions. The first option in each distinction is the FCC’s traditional approach: 1. The definition of harmful interference can be qualitative or quantitative. 2. Analyses of service rules can be worst-case or multi-case. 3. Analyses of service rules can be qualitative or quantitative. 4. Final service rules can be single-value or statistical. 5. Final service rules can be quantitative or qualitative. Section II explains our four findings. In summary, the FCC’s: 1. Technical analysis and final rules fail to quantify harmful interference. 2. Customary analysis of service rules is worst-case. 3. Resulting service rules are almost always single-value. 4. Analysis of service rules is generally qualitative and resulting service rules are usually quantitative. Section III presents the Northpoint case to illustrate the application of the above criteria and findings. “Northpoint” was a controversy about the FCC’s approval of Multichannel Video Distribution and Data Service (MVDDS) — a terrestrial wireless broadband technology. Northpoint, a developer of MVDDS, tried to obtain approval to operate terrestrial transmitters in the face of objections from the incumbent operators of direct broadcast satellite receivers. In Northpoint, the FCC never quantified harmful interference in its technical analysis nor final rules, and it started with a multi-case analysis of service rules that ended in single-value service rules.

Optimized handover and resource management: an 802.21‐based scheme to optimize handover and resource management in hybrid satellite‐terrestrial networks

SUMMARYSatellite communications can provide fourth generation (4G) networks with large‐scale coverage. However, their integration to 4G is challenging because satellite networks have not been designed with handover in mind. The setup of satellite links takes time, and so, handovers must be anticipated long before. This paper proposes a generic scheme based on the Institute of Electrical and Electronics Engineers 802.21 standard to optimize handover and resource management in hybrid satellite‐terrestrial networks. Our solution, namely optimized handover and resource management (OHRM), uses the terrestrial interface to prepare handover, which greatly speeds up the establishment of the satellite link. We propose two mechanisms to minimize the waste of bandwidth due to wrong handover predictions. First, we leverage the support of 802.21 in the terrestrial access network to shorten the path of the signaling messages towards the satellite resource manager. Second, we cancel the restoration of the satellite resources when the terrestrial link rolls back. We use OHRM to interconnect a digital video broadcasting and a wireless 4G terrestrial network. However for the simulation tool, we use a WiMAX as the terrestrial technology to illustrate the schemes. The simulation results show that OHRM minimizes the handover delay and the signaling overhead in the terrestrial and satellite networks. Copyright © 2013 John Wiley & Sons, Ltd.

Preliminary Application of Terrestrial 3D LiDar in Corridor Defects Detection of Overhead Transmission Lines

Based on a brief introduction of the operational principle of terrestrial 3D LiDar, this paper describes some typical defects detection methods of security distance in the overhead transmission line with living examples. These tests are realized by the Z+F Imager 5010 terrestrial 3D LiDar and Polyworks. The research results show that terrestrial LiDar technology can achieve the defect evaluation of defect detection of security distance in the overhead transmission lines. And this technology has many advantages, such as portable, security, intuitive and high precision.

Low Satellite Visibility Areas: Extension of the GPS Capabilities to Deploy Location-Based Services

In this article, the use of IEEE 802.11 technology is used for the problem of augmenting the coverage of satellite positioning systems when less than four satellites are visible, by using a low complexity and effective technique involving a terrestrial radio technology. The solution consists of processing the information received by the terrestrial infrastructure for introducing virtual satellites to obtain the minimum number of satellites needed for fixing the receiver position. The feasibility and the achievable performance is demonstrated experimentally by implementing real prototypes using either sophisticated or low-cost receivers in different experiments. The results obtained are comparable, in terms of error magnitude, with those of a plain GPS receiver when four satellites are visible.

Digital radio and market failure: a tale of two complementary platforms

PurposeIn sharp contrast to television, various sources of market failure currently prevent market forces fulfilling the promise of digital switchover in radio markets. The purpose of this paper is to review the strengths and weaknesses, business models and market deployment of the two main platforms, with a view to establishing the economic case for higher regulatory involvement in digital radio markets.Design/methodology/approachThe paper analyses the relevant broadcaster, engineering and regulatory literature, with particular emphasis on technical compatibilities among terrestrial radio broadcast technologies, and the technological and economic difficulties they face. The exercise is the first of its kind to scope and bring together these multidisciplinary contributions.FindingsThe highly uncoordinated development and deployment of terrestrial digital radio platforms is leading this new digital industry to an impasse. There is a legacy of uncertainty and scepticism amongst market players. Furthermore, prevailing technology and business models have marginalised community radio services and regional audiences.Research limitations/implicationsThe analysis does not cover the demand side (contents, culture) nor developments in non‐terrestrial digital platforms, nor in the US‐based IBOC standard.Practical implicationsThere is considerable scope, particularly in large, sparsely inhabited countries with sizeable rural audiences to remedy the failings of the current fragmented approach through regulatory intervention through platform integration.Originality/valueThere is a lack of coherent information published on the potential benefits that the new digital platforms are bringing to the audio broadcasting market, and on the current market difficulties they face. The article remedies this gap.

Proactive TCP Mechanism to Improve Handover Performance in Mobile Satellite and Terrestrial Networks

Emerging standardization of Geo Mobile Radio (GMR-1) for satellite system is having strong resemblance to terrestrial GSM (Global System for Mobile communications) at the upper protocol layers and TCP (Transmission Control Protocol) is one of them. This space segment technology as well as terrestrial technology, is characterized by periodic variations in communication properties and coverage causing the termination of ongoing call as connections of Mobile Nodes (MN) alter stochastically. Although provisions are made to provide efficient communication infrastructure this hybrid space and terrestrial networks must ensure the end-to-end network performance so that MN can move seamlessly among these networks. However from connectivity point of view current TCP performance has not been engineered for mobility events in multi-radio MN. Traditionally, TCP has applied a set of congestion control algorithms (slow-start, congestion avoidance, fast retransmit, fast recovery) to probe the currently available bandwidth on the connection path. These algorithms need several round-trip times to find the correct transmission rate (i.e. congestion window), and adapt to sudden changes connectivity due to handover. While there are protocols to maintain the connection continuity on mobility events, such as Mobile IP (MIP) and Host Identity Protocol (HIP), TCP performance engineering has had less attention. TCP is implemented as a separate component in an operating system, and is therefore often unaware of the mobility events or the nature of multi-radios' communication. This paper aims to improve TCP communication performance in Mobile satellite and terrestrial networks.

Implementation of DTT in Spain: Technological barriers to entry and consolidation of terrestrial technology

This paper analyzes the process of television digitalization in Spain and its regulatory framework, concluding that the promotion of already established terrestrial technology has resulted in the development of entry barriers to alternative technologies, such as satellite. The Spanish regulation and its implementation are analyzed in this paper, especially with regard to public funding to support the development of terrestrial networks. The conclusion suggests that the Spanish regulatory bodies should define an interconnection framework to allow different operators to compete in distribution. Additionally, the separation of the various satellite markets, in particular transport to feed terrestrial networks and direct to home distribution (DTH), would be advisable. Key words: Transition to digital TV, regulation, barriers to entry, broadcasting services, satellite, Spain.

Hybrid Wireless Networks for E-Learning and Digital Literacy

Today, satellite communication networks are being integrated into the infrastructure of modern Terrestrial communication networks and becoming popular for the delivery of educational content and data, as well as education-centric services, including information, tele-conferencing, entertainment, or ‘edutainment’ services. With fresh demand for new services and applications, it is becoming essential that wireless network architecture seamlessly interoperate with new and existing technologies, protocols and standards. This paper presents recent work on the use of hybrid wireless network infrastructures for delivering tele-education and e-learning applications to remote communities by combining a variety of satellite, terrestrial and wireless technologies, and provides the results from live scenarios carried out employing various methods of interoperability testing. The analysis of the results examines a number of different issues such as delay, jitter, packet loss, latency, throughput measurement, and bandwidth. By combining satellite and terrestrial (wireless) technologies, full coverage and high capacity can be achieved for true broadband services for delivering educational content. The interoperability among such diverse networks imposes a number of challenges regarding service provision and management.

Contribution of GNSS CORS Infrastructure to the Mission of Modern Geodesy and Status of GNSS CORS in Thailand

Geodesy is the science of measuring and mapping the geometry, orientation and gravity field of the Earth including the associated variations with time. Geodesy has also provided the foundation for high accuracy surveying and mapping. Modern Geodesy involves a range of space and terrestrial technologies that contribute to our knowledge of the solid earth, atmosphere and oceans. These technologies include: Global Positioning System/Global Navigation Satellite Systems (GPS/GNSS), Satellite Laser Ranging (SLR), Very Long Baseline Interferometry (VLBI), Satellite Altimetry, Gravity Mapping Missions such as GRACE, CHAMP and GOCE, satelliteborne Differential Interferometric Synthetic Aperture Radar (DInSAR), Absolute and Relative Gravimetry, and Precise Terrestrial Surveying (Levelling and Traversing). A variety of services have been established in recent years to ensure high accuracy and reliable geodetic products to support geoscientific research. The reference frame defined by Modern Geodesy is now the basis for most national and regional datums. Furthermore, the GPS/GNSS technology is a crucial geopositioning tool for both Geodesy and Surveying. There is therefore a blurring of the distinction between geodetic and surveying GPS/GNSS techniques, and increasingly the ground infrastructure of continuously operating reference stations (CORS) receivers attempts to address the needs of both geodesists and other positioning professionals. Yet Geodesy is also striving to increase the level of accuracy by a factor of ten over the next decade in order to address the demands of “global change” studies. The Global Geodetic Observing System (GGOS) is an important component of the International Association of Geodesy. GGOS aims to integrate all geodetic observations in order to generate a consistent high quality set of geodetic parameters for monitoring the phenomena and processes within the “System Earth”. Integration implies the inclusion of all relevant information for parameter estimation, implying the combination of geometric and gravimetric data, and the common estimation of all the necessary parameters representing the solid Earth, the hydrosphere (including oceans, ice-caps, continental water), and the atmosphere. This paper will describe the background to the establishment of GGOS, discuss the important role to be played by GPS/GNSS infrastructure in realising the GGOS mission and provide an update status of GNSS CORS in Thailand.