Fly-By-Wireless for Next Generation Aircraft: Challenges and Potential solutions

”Fly-By-Wireless” paradigm based on wireless connectivity in aircraft has the potential to improve efficiency and flexibility, while reducing weight, fuel consumption and maintenance costs. In this paper, first, the opportunities and challenges for wireless technologies in safety-critical avionics context are discussed. Then, the assessment of such technologies versus avionics requirements is provided in order to select the most appropriate one for a wireless aircraft application. As a result, the design of a Wireless Avionics Network based on Ultra WideBand technology is investigated, considering the issues of determinism, reliability and security

Real-Time Ethernet Solutions supporting Ring topology from an Avionics Perspective: a Short Survey

To cope with the increasing quantity of wires, thus the weight and integration costs in avionics, an implementation of a new avionics communication architecture with less cables will clearly improve the efficiency of aircraft, while reducing the deployment costs. Furthermore, such a communication ar- chitecture shall be efficient to meet the design requirements, in terms of predictability and availability, for the least amount of money. Therefore, the AFDX compatibility, a minimized (re)- configuration effort and costs are among the most important issues to guarantee. On the other hand, the recent research effort towards defining new communication solutions, to guarantee a high availability level with limited cabling complexity for real- time applications, has renewed the interest in ring topology. Therefore, the main objective of this paper is benchmarking the most relevant solutions, based on Ethernet technology and supporting ring topology, vs avionics requirements, and we particularly focus on the main Performance Indicators, specified in IEC 61784-2, of each one of them

MIoTy Overview: a Mathematical Description of the Physical layer

MIoTy is a relatively new Low Power Wide Area Network system. The aim of the thesis is to get an overall understanding of the system and an in-depth understanding of the Physical Layer. In particular, a mathematical description of the physical layer is the final aim, Telegram Splitting Multiple Access (TSMA) is the main invention in the MIoTy the technology uses an algorithm to parse the data packets to be transmitted into small sub-packets at the transmission source. MIoTy is based on the protocol family telegram splitting ultra narrowband (TS-UNB) of the ETSI TS 103 357 standards. These TSMA systems have a data rate of 512 bit/s. The UNB telegram is divided at the physical layer into multiple sub-packets, each equal in size. Each of which is randomly sent on a different carrier frequency and at a different time. The sub-packets are much smaller than the original telegram and only require an on-air time of 16 ms. The total air-time of all the sub-packets for a 10-byte telegram is about 390 ms. The risk of suffering data loss resulting from interference is substantially reduced due to a combination of the virtually random distribution of sub-packet transmissions through time and varying frequencies. And, as a result of the use of sophisticated forward error correction (FEC) techniques, the receiver needs only about 50% of the packets to reconstruct the original telegram completely.MIoTy is a relatively new Low Power Wide Area Network system. The aim of the thesis is to get an overall understanding of the system and an in-depth understanding of the Physical Layer. In particular, a mathematical description of the physical layer is the final aim, Telegram Splitting Multiple Access (TSMA) is the main invention in the MIoTy the technology uses an algorithm to parse the data packets to be transmitted into small sub-packets at the transmission source. MIoTy is based on the protocol family telegram splitting ultra narrowband (TS-UNB) of the ETSI TS 103 357 standards. These TSMA systems have a data rate of 512 bit/s. The UNB telegram is divided at the physical layer into multiple sub-packets, each equal in size. Each of which is randomly sent on a different carrier frequency and at a different time. The sub-packets are much smaller than the original telegram and only require an on-air time of 16 ms. The total air-time of all the sub-packets for a 10-byte telegram is about 390 ms. The risk of suffering data loss resulting from interference is substantially reduced due to a combination of the virtually random distribution of sub-packet transmissions through time and varying frequencies. And, as a result of the use of sophisticated forward error correction (FEC) techniques, the receiver needs only about 50% of the packets to reconstruct the original telegram completely

Halogenated organic species over the tropical South American rainforest

Airborne measurements of the halogenated trace gases methyl chloride, methyl bromide and chloroform were conducted over the Atlantic Ocean and about 1000 km of pristine tropical rainforest in Suriname and French Guyana (3–6° N, 51–59° W) in October 2005. In the boundary layer (0–1.4 km), maritime air masses, advected over the forest by southeasterly trade winds, were measured at various distances from the coast. Since the organohalogens presented here have relatively long atmospheric lifetimes (0.4–1.0 years) in comparison to the advection times from the coast (1–2 days), emissions will accumulate in air traversing the rainforest. The distributions of methyl chloride, methyl bromide and chloroform were analyzed as a function of time the air spent over land and the respective relationship used to determine net fluxes from the rainforest for one week within the long dry season. <br><br> Net fluxes from the rainforest ecosystem have been calculated for methyl chloride and chloroform as 9.5 (±3.8 2σ) and 0.35 (±0.15 2σ)μg m<sup>-2</sup> h<sup>−1</sup>, respectively. No significant flux was observed for methyl bromide within the limits of these measurements. <br><br> The global budget of methyl chloride contains large uncertainties, in particular with regard to a possible source from tropical vegetation. Our measurements are used in a large-scale approach to determine the net flux from a tropical ecosystem to the planetary boundary layer. The obtained global net flux of 1.5 (±0.6 2σ) Tg yr<sup>-1</sup> for methyl chloride is at the lower end of current estimates for tropical vegetation sources, which helps to constrain the range of tropical sources and sinks (0.82 to 8.2 Tg yr<sup>-1</sup> from tropical plants, 0.03 to 2.5 Tg yr<sup>-1</sup> from senescent/dead leaves and a sink of 0.1 to 1.6 Tg yr<sup>-1</sup> by soil uptake). Nevertheless, these results show that the contribution of the rainforest ecosystem is the major source in the global budget of methyl chloride. <br><br> For chloroform, the extrapolated global net flux from tropical ecosystems is 56 (±23 2σ) Gg yr<sup>−1</sup>, which is of minor importance compared to the total global sources and might be already contained in the soil emission term

Systems study for an Integrated Digital-Electric Aircraft (IDEA)

The results of the Integrated Digital/Electric Aircraft (IDEA) Study are presented. Airplanes with advanced systems were, defined and evaluated, as a means of identifying potential high payoff research tasks. A baseline airplane was defined for comparison, typical of a 1990's airplane with advanced active controls, propulsion, aerodynamics, and structures technology. Trade studies led to definition of an IDEA airplane, with extensive digital systems and electric secondary power distribution. This airplane showed an improvement of 3% in fuel use and 1.8% in DOC relative to the baseline configuration. An alternate configuration, an advanced technology turboprop, was also evaluated, with greater improvement supported by digital electric systems. Recommended research programs were defined for high risk, high payoff areas appropriate for implementation under NASA leadership

Distributed Control System for Turbine Engines

A distributed control system (DCS) for a turbine engine has been demonstrated an

Application of a global positioning system in Saudi Arabia

Navigation constitutes the major part of safety at sea; the more accurate position fixing, the more safety exists. Nowadays Global Positioning System (GPS) is the most accurate system but it exists only in a few countries. However, to promote standard navigation, GPS should exist all around the world. It is not only used for position fixing at sea, but also in the air and on land. GPS is more accurate position fixing system than any other existing system with world coverage. The plan is for an absolute accuracy of within 100m to be available to the general user such as the merchant marines of all countries. An accuracy of about 16m will be obtained by the US and NATO military and other authorized users. Besides position fixing in three dimensions (longitude, latitude and altitude above sea level) GPS will provide the user with velocity information and with Universal Time Coordinated (UTC). Because of the high accuracy in three dimensions, GPS could also be used for geodetic and other purposes. Since Saudi Arabia has an important role to play in International Trade and Economy, the application of GPS would enable the country to embrace the future in the correct manner. Moreover, Saudi Arabia has a very long coast with many coral reefs along the Red Sea and a heavy trafficated coast on the Arabian Gulf. GPS is, therefore, necessary for the coast guard to maintain its duty properly and safely

Halogenated organic species over the tropical rainforest

International audienceAirborne measurements of the halogenated trace gases methyl chloride, methyl bromide and chloroform were conducted over the Atlantic Ocean and 1000 km of pristine tropical rainforest in Suriname and French Guyana (3–6° N, 51–59° W) in October 2005. In the boundary layer (0–1.4 km), maritime air masses initially low in forest hydrocarbons, advected over the forest by southeasterly trade winds, were measured at various distances from the coast. Since the organohalogens presented here have relatively long atmospheric lifetimes (0.4–1.0 years) in comparison to the transport times (1–2 days), emissions will accumulate in air traversing the rainforest. The distributions of methyl chloride, methyl bromide and chloroform were analyzed as a function of forest contact time and the respective relationship used to determine fluxes from the rainforest during the long dry season. Emission fluxes have been calculated for methyl chloride and chloroform as 9.4 (±4.0 2s) and 0.34 (0.14± 2s) µg m-2 h-1, respectively. No significant flux from the rainforest was observed for methyl bromide within the limits of these measurements. The flux of methyl chloride was in general agreement with the flux measured over the same region in March 1998 during the LBA Claire project using a different analytical system. This confirms that the rainforest is a strong source for methyl chloride and suggests that this emission is relatively uniform throughout the year. In contrast the chloroform flux derived here is a factor of three less than previous measurements made in March 1998 suggesting a pronounced ecosystem variation. The differences in chloroform fluxes could not be attributed to either temperature or rainfall changes. The global extrapolation of the derived fluxes led to 1.5 (±0.6 2s) Tg yr-1 for methyl chloride, which is in the range of the missing source postulated by previous model studies and 55 (±22 2s) Gg yr-1 for chloroform

Radio Altimeter Tolerance of Wireless Avionics Intra-Communications Systems

Avionics in modern aircraft have multiple redundant wiring paths in case of failure. The aerospace industry acquired spectrum for wireless avionics which would reduce the amount of necessary wiring, but must prove compatibility with the radio altimeters incumbent to the band for certification. This work covers the development of a reference test bed validated by radio altimeter and aircraft manufacturers. This test bed was automated in a modular framework which allowed the rapid modification of software to suit a wide variety of test conditions. This work also covers the three altimeter testing regimens which used this test bed, and the development of reporting formats which supported the creation of international standards based on these results