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In astronomy and celestial navigation, an ephemeris (pl. ephemerides; ) is a book with tables that gives the trajectory of naturally occurring astronomical objects as well as artificial satellites in the sky, i.e., the position (and possibly velocity) over time. Historically, positions were given as printed tables of values, given at regular intervals of date and time. The calculation of these tables was one of the first applications of mechanical computers. Modern ephemerides are often provided in electronic form. However, printed ephemerides are still produced, as they are useful when computational devices are not available. The astronomical position calculated from an ephemeris is often given in the spherical polar coordinate system of right ascension and declination, together with the distance from the origin if applicable. Some of the astronomical phenomena of interest to astronomers are eclipses, apparent retrograde motion/planetary stations, planetary es, sidereal time, posit

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ENV-340: Fundamentals of satellite positioning

Bases des références géodésiques, principe de mesure utilisé en localisation par satellites et de l'estimation de la qualité de positions GNSS (Global Navigation Satellites Systems).

PHYS-101(en): General physics : mechanics (English)

Students will learn the principles of mechanics to enable a better understanding of physical phenomena, such as the kinematics and dyamics of point masses and solid bodies. Students will acquire the capacity to quantitatively analyze these effects with the appropriate theoretical tools.

EE-585: Space mission design and operations

This course is a "concepts" course. It introduces a variety of concepts in use in the design of a space mission, manned or unmanned, and in space operations. it is at least partly based on the practical space experience of the lecturer.

Demands of the Road An Assisted-GNSS Solution Uses the EGNOS Data Access Service

Cyril Botteron, Jérôme Leclère

For use in billing drivers in road-user charging schemes, onboard units employing GNSS must meet stringent reliability and availability requirements, and at the same time, be based on low-cost equipment systems. The SIGNATURE unit includes an assistance service which provides ephemeris data and corrections from EDAS, optimized for user location.

2011

An Assisted-GNSS Solution for Demanding Road Applications using the EGNOS Data Access System (EDAS)

Cyril Botteron, Jérôme Leclère

This paper describes a prototype solution which has been developed to provide both the positioning availability and integrity required for this application. The SIGNATURE (SImple GNSS Assisted & TrUsted REceiver) solution includes an assistance service which provides ephemeris data and corrections from the EGNOS Data Access Service (EDAS), optimized for the user location. Assistance messages are sent to OBUs which can either host an experimental receiver or a Commercial-Off-The-Shelf (COTS) receiver. Measurement data from the receiver is then processed with application-specific navigation algorithms on the OBU which aim to improve the integrity of the position solution relative to standard solutions. The paper describes the SIGNATURE solution and how it is being tested in the course of the project. It then presents initial results from field trials which are assessing its performance in a range of representative conditions. The tests assess the contribution that assistance can make to positioning performance, and illustrate options for enhancing standard assistance solutions. Enhancements to assistance encompass modifications to the message content and alternative means of communications, showing the benefits and feasibility of a broadcast service. The impact of including EGNOS corrections through a broadcast assistance service in urban areas is also under investigation.

2010

An Assisted-GNSS Solution for Demanding Road Applications using the EGNOS Data Access System (EDAS)

Cyril Botteron, Jérôme Leclère

Roads right across Europe are becoming more congested and governments and regional authorities are looking for ways to better manage the existing road network. One tool that is being increasingly promoted to tackle the congestion challenge is Road User Charging (RUC). Recording journey information using a GNSS receiver embedded in an OBU is a convenient and flexible solution to support the automated fee collection process. If GNSS positioning is to be used as the basis for billing drivers though it must meet stringent reliability and availability requirements, and at the same time, be based on low-cost equipment. This paper describes a prototype solution which has been developed to provide both the positioning availability and integrity required for this application. The SIGNATURE (SImple GNSS Assisted & TrUsted REceiver) solution includes an assistance service which provides ephemeris data and corrections from the EGNOS Data Access Service (EDAS), optimized for the user location. Assistance messages are sent to OBUs which can either host an experimental receiver or a Commercial-Off-The-Shelf (COTS) receiver. Measurement data from the receiver is then processed with application-specific navigation algorithms on the OBU which aim to improve the integrity of the position solution relative to standard solutions.

2010

Star

A star is an astronomical object comprising a luminous spheroid of plasma held together by self-gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night;

Orbit

In celestial mechanics, an orbit (also known as orbital revolution) is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet,

Heliocentrism

Heliocentrism (also known as the Heliocentric model) is the astronomical model in which the Earth and planets revolve around the Sun at the center of the universe. Historically, heliocentrism was op