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Radio Science Radio Science IssuesIssues

François Lefeuvre, François Lefeuvre, URSI President, LPCE/CNRS URSI President, LPCE/CNRS

45071 Orléans cedex 2, France45071 Orléans cedex 2, France

ESWW4 - Bruxelles – 6 November ESWW4 - Bruxelles – 6 November 20072007

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The radio spectrum The radio spectrum

An exploding use for a An exploding use for a unique limited resourceunique limited resource

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1. Radio spectrum1. Radio spectrum

2.Radio Science & 2.Radio Science & Telecommunication Telecommunication

3. URSI scientific activities3. URSI scientific activities

4. Present issues4. Present issues

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1. THE RADIO 1. THE RADIO SPECTRUMSPECTRUM

5The Electromagnetic spectrum

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geophysics, atmospherics,plasma instabilities

navigation & naval comm.Amateurs radio

emissions from astr. objectsfluct. thermal noise (radiometers)

satellite comm. and broadcasting, Wi-Fi (5 GHz),

radars for remote sensing

plasma instabilities from planetary & Sun envirt.

TV and radio broadcastingradars (incl. ionosph. and troposph.- stratosph. radars)

micro wave applications

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MICROWAVES

Mobile phone: 0.9, 1.8, 1.9 GHzGPS: 1.2, 1.5 GHzDECT: 1.8, 1.9 GHzWi-fi: 2.4, 5 GHzetc.

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2. RADIO SCIENCE AND 2. RADIO SCIENCE AND TELECOMMUNICATIONTELECOMMUNICATION

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The Birth of URSI

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Emission at 850 kHz from Poldhu (Cornwal)Reception at St John, Newfounland (Canada))

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Two models were investigated to explain the Marcony observations :

- surface diffraction

- atmospheric reflection

In parallel,

-The Belgian kings Leopold II and Albert 1er pushed Robert Goldschmidtto develop radio links between 2 towns of Belgium Congo and betweenBelgium and Congo

-The French government investigated the possibility of a radio link between France and Morocco

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■ October 1913, creation of the « Commission Internationale de TSF

■ July 1919 , creation of the « International Union of Scientific Radiotelegraphy »,

which very soon became URSI

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The ionosphere was discovered in the early twenties and the propagation laws of an EM wave in a plasma were established in the early thirties.

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URSIURSI Union Radio Scientifique Union Radio Scientifique InternationaleInternationale International Union of Radio International Union of Radio ScienceScience

has for objective to stimulate and to has for objective to stimulate and to coordinate, on an international basis, studies coordinate, on an international basis, studies in the fields of radio, telecommunication, and in the fields of radio, telecommunication, and electronic scienceselectronic sciences

- URSI Secretariat, c/o INTEC, University of Ghent- URSI Secretariat, c/o INTEC, University of Ghent http://http://www.ursi.orgwww.ursi.org- 42 National Committees- 42 National Committees- 10 Scientific Commissions- 10 Scientific Commissions- several standing committees- several standing committees

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URSI is an ICSU Scientific Union

ICSU (International Council for Science) is part of UNESCO. It is considered as the “voice” of Science. It is engaged in numerous actions concerning science and society .

It consists of :

- National Members (Academies)

- Scientific Unions (29) such as IAU (International Astronomical Union), IUGG/IAGA (International Union of Geodesy and Geophysics / International Association of Geomagnetism and Aeronomy)

- Scientific Associates (19)

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Interdisciplinary Bodies (IBs) have been created by ICSU Scientific Unions (including URSI)

URSI in involved in

- COSPAR (Committee on Space and Research)

- FAGS (Federation of Astronomical and Geophysical Data Analysis) and its ISES (International Space Environment Service) service

- IUCAF (Scientific Committee on frequency Allocations for Radio Astronomy and Space Science)

- SCAR (Scientific Committee on Antarctic Research)

- SCOSTEP (Scientific committee On Solar-Terrestrial Physics)

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Management of the radio spectrum

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The management of the radio spectrum is under the responsibility of

ITU (International Telecommunication Union)

leading United Nations agency for information and communications technologies, with 3 core sectors:

- Radio communication - Standardization- Development

ITU is an ICSU partner.

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URSI, which is a sector member of ITU, pursue radio sciences activities upstream of

ITU

Professional Societies like IEEE, IEE, SEE, etc pursue R&D activities upstream of ITU

Radioscientists belong both to ITU, URSI and professional societies

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3. URSI SCIENTIFIC 3. URSI SCIENTIFIC ACTIVITIESACTIVITIES

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A. Electromagnetic Metrology

Development and refinement of new measurement techniques

- based on EM principles (e.g. precise time and wavelength measurements)

- or used for the characterization of EM properties of materials and electromagnetic dosimetry with applications in industry, environment ad security, health and safety, communications, etc.

Primary standards, including those based on quantum phenomena: realization and diffusion of time and frequency standards

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LNE &LNE-SYRTE/OP

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B. Fields and waves, EM theory and applications

Analytical, numerical and measurement techniques to understand electromagnetic phenomena- development of antennas and antenna arrays- propagation including waves in specialized media like Metamaterials (MTMs) where n, ε and μ can be made <0- application of EM fields as a non-destructive tool

Inverse scattering and imaging

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-10

0

10

20

30

40

50

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

theta (°)

SE

R V

V

PO MoM

Simulation of surface currents (F Molinet)

Equivalent radar surface of the plane - From a Physical Optic (PO) approximationand from a numerical simulation (F. Molinet)

MTMs may lead to new physics and engineering concepts MT

(R. W. Ziolkowski)

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C. Radio-Communication systems and signal

processing Research and development in:

- Radio-Communication and Telecommunication Systems- spectrum and medium utilization- information theory, coding, modulation and

detection- signal and image processing

In order to communicate with anyone, anywhere, any time require new concepts like « reconfigurable radio and cognitive radio ».

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Cognitive Radio and other Cognitive Radio and other RadiosRadios

RADIOSDRSOFTWARE DEFINED RADIO

POLICY-BASED

ADAPTIVE RADIO

COGNITIVE RADIO

RECONFIGURABLE RADIO

Software defined radio (SDR): A radio in which RF operating parameters including but not limited to frequency range, modulation type, or output power can be set or altered by software, and/or the technique by which this is achieved

Cognitive radio (CR): A radio or system that senses, and is aware of, its operational environment and employs knowledge representation, automated reasoning and machine learning mechanisms in establishing, conducting, or terminating communication or networking functions with other radios. Cognitive radios can be trained to dynamically and autonomously adjust their radio operating parameters accordingly.

Policy-based adaptive radio (PBAR): A radio that is governed by a predetermined sets of rules for behaviour that are independent of the radio implementation regardless of whether the implementation is in hardware or software and both senses and adapts to its environment.

Reconfigurable radio (CR): A reconfigurable radio is a radio whose hardware functionality can be changed under software control

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D. Electronics and photonics

Research of the new electronic and photonic devices and systems permitting the development of digital computers, Television and mobile communications, etc.- semiconductor lasers- optical fibers,- microwave integrated circuits- nano-optics and nano-electronics

Device for generation, detection, storage and processing of EM signals together with their applications from the low frequencies to the optical domain

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On the announcement of the 2007Conference of the French URSI Committee :

- nano device for fast (20-100 µs)commutation

- light distribution in an hexagonal photonic crystal cavity

- scale for molecular electronic

-carbon nano-tube (diameter : ~ 10 nanometers), with specificproperties (conductivity) to be used for electronic components (e.g. transistors).

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E. Electromagnetic Noise and Interference

Investigation of the level and of the effects of natural and man-made noises on the performances of radio, TV, phones, navigation instrument, etc.

- adaptation of test techniques to impulsive and higher frequency noises

- questions raised by new concepts like Power Line Communications (PLC)

- definition of new standards and norms

Terrestrial and planetary noise of natural origin, seismic associated electromagnetic fields

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Application of Power Line Communication (PLC) to the transmission of commands withina car

Spectrum of theEM noise in theEarth environt

P. Degauque

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F. Wave propagation and remote sensing

Study of wave propagation and of wave interactions in non ionized media- neutral atmosphere- planetary surfaces and subsurfaces (including land, ocean and ice)

Applications in the areas of remote sensing and communications

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Soil moisture from brightness obtained with the ESTAR L-bandRadiometer (Camp and Swift)

Use of radio-interferometryto identify ground movements(e.g. after earthquakes), accurate topography, etc.

Here, use of ESR1 data at18 months difference to Point out displacements after The 1992 Landers quake.Comparisons with a modelTo remove uncertainties(D. Massonnet)

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Tsunami ocean wave from altimeter overpass

Winds in hurricanes

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G. Ionospheric Radio and Propagation

Study of the ionosphere in order to provide the broad understanding necessary to support space and ground-based radio systems. Global morphology and modeling of Global morphology and modeling of

the ionosphere;the ionosphere; Ionospheric space-time variations; Ionospheric space-time variations; Development of tools and networks Development of tools and networks

needed to measure ionospheric needed to measure ionospheric properties and trends; properties and trends;

Theory and practice of radio Theory and practice of radio propagation via the ionosphere; propagation via the ionosphere;

Application of ionospheric Application of ionospheric information to radio systems.information to radio systems.

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Ionospheric space-time Ionospheric space-time variationsvariations

Assimilative mapping Assimilative mapping techniques (borrowed techniques (borrowed from the Met from the Met Community)Community) Examples are GAIM in Examples are GAIM in

the USAthe USA EDAM in EuropeEDAM in Europe

Assimilative models Assimilative models take data from various take data from various sources and add them sources and add them to a background model to a background model in a controlled way to in a controlled way to generate a current and generate a current and forecast map of the forecast map of the ionosphereionosphere

EDAM mapping of the October 2003 Storm. Copyright QinetiQ

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H. Waves in Plasmas

Study of the generation, propagation and interactions of EM (and ES) waves with space and laboratory plasmas and with other waves

Applications - in the study of the variations of the

environment of the Earth and of the planets,and of other astrophysical objects- in Space Weather (spacecraft-plasma

interactions, modeling of the radiation belts)

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Waves and turbulences play afundamental role in the dynamics of particles in the sun corona, thesolar wind, the planetary and Earth environment, etc.

Electromagnetic waves in plasma may be the signature of man-made noise (in red, effects of ground based transmitters in the frequency range : 18 – 22 kHz)

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J. Radio Astronomy

Observation and interpretation of all radio emissions and reflections from celestial objects

Emphasis is placed on:- the promotion of technical means for making radio-astronomical observations and data analysis- support of activities to protect radio-astronomical observations from harmful interference

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Our beautiful radio Our beautiful radio universeuniverse

Cygnus Aa radio galaxy

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New designs for dishes + New designs for dishes + single pixel feedssingle pixel feeds

15 m fibreglass+foam dish (<2mm rms)USA

6m hydroformed dish

South Africa

Canada 10 m composite dish

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K. Electromagnetics in biology and medicine

effects of and mechanisms involved with exposure of biological systems (in general) and of humans (in particular) to EM waves

Applications to - studies on effects of radars, power

lines, cell phones- medical use of exposures to EM

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EM Pulses from 0.1 to a few 100 Hz are non-ionizing but are able to induce significant biological currents in tissues.

Time (msec)0 500 1000 3000 3500

Exp

osu

re (

mic

roT

esla

)

-300

-200

-100

0

100

200

300Refractory PeriodFast Rise

Pulse Segment

(Thomas et al.)

Some treatments: Bone formation / fractures, Cancer , (tumour growth), congenitalpseudarthrosis, depression, joint disorders, nerve regeneration, osteoarthritis, Pain

Portable Magnetic Field Exposure Unit

Dedicated devices and modelsare used to simulate phenomenaproduced by the interaction ofEM fields with surroundingobjects, human tissues, …

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4. PRESENT ISSUES4. PRESENT ISSUES

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Reduce the gap between Telecommunication and Radio

Science

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Demands for a more operational use of the radio spectrum exists.

Cognititive radios and other radios allow that evolution.

The point is the full implementation of predetermined sets of rules

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Forum on Radio Science and

Telecommunications

URSI – General Assembly – Chicago (11-16 August 2008)

- General Lecture (Friday 15, 11.00 – 12.00)Wireless Communications in 2020

- Forum (Friday 15, 13.40 – 17.20)- Cognitive radio- Ultra wide band- Interference management- health aspects- open discussion

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Develop Radio Science in developing countries

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The radio spectrum is a unique common limited The radio spectrum is a unique common limited resource (developing countries included)resource (developing countries included)

Its management require agreements between Its management require agreements between all users (radioscientists included)all users (radioscientists included)

Except in specific cases (e.g. the existence of Except in specific cases (e.g. the existence of international equipments) developing countries international equipments) developing countries generally don’t invest on radio sciencegenerally don’t invest on radio science

The point is to identify priorities for The point is to identify priorities for development in radio sciencedevelopment in radio science

The three ICSU Regional offices (Africa, Asia, The three ICSU Regional offices (Africa, Asia, Latin America and Caribbean) have defined Latin America and Caribbean) have defined priorities. The common one : “Natural and priorities. The common one : “Natural and Human induced hazards and disasters”Human induced hazards and disasters”

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ICSU list of hazards and disasters

- hazards related to hydrometeorological and geophysical trigger events, i.e. earthquakes, volcanoes, flooding storms (hurricanes, typhoons, etc.)

- heat waves

- droughts and fires

- tsunamis

- coastal erosion

- landslipes

- aspects of climate change (for example, increases of extreme events)

- space weather and impacts by near-Earth objects

- and related events such as wild fires and locust outbreaks

- The effects of human activities on creating or enhancing hazards, including land-use practices should be included

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Possible involvement of URSI in Possible involvement of URSI in disaster managementdisaster management

WG to study and develop guidelines related:WG to study and develop guidelines related:

(a) to communication systems to set up at (a) to communication systems to set up at the time the time and after disaster,and after disaster,

(b) to the use of remote sensing data for: (b) to the use of remote sensing data for: - monitoring and alert,- monitoring and alert,- description of the disturbed - description of the disturbed

environment at environment at the time of disasterthe time of disaster- description of the environment after - description of the environment after

the time the time of disasterof disaster

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Answer societal demands for « objective » information

(without expressing position or/and support)

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White paper on SPS White paper on SPS (June 2007 Radio Science Bulletin issue)

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The SPS concept

Solar energy is collected in space by a satellite in a Solar energy is collected in space by a satellite in a geostationary orbitgeostationary orbit

The solar energy is converted to direct current by The solar energy is converted to direct current by solar cellssolar cells

The direct current is in turned used to power The direct current is in turned used to power microwave generators in the GHz frequency microwave generators in the GHz frequency (microwave) range(microwave) range

The generators feed a highly directive satellite-The generators feed a highly directive satellite-borne antenna, which beams the energy to the borne antenna, which beams the energy to the EarthEarth

On the ground, a rectifying antenna (rectenna) On the ground, a rectifying antenna (rectenna) converts the microwave converts the microwave energyenergy from the satellite from the satellite into direct currentinto direct current

After suitable processing, the current is fed to the After suitable processing, the current is fed to the power gridpower grid

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Typical SPS unit :- solar panel area of ~10 km2- transmitting antenna of ~ 2 km diameter- rectenna ~4 km in diameter- electric power output ~ 1 GW

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Among the points addressed in the URSI WP:

- comparison of the output power from a space-based and a terrestrial-based solar power unit

-required technology

- required pointing accuracy

- effects of solar-wind particles and solar radiation on solar cells

- lifetime and maintenance

- linear and non-linear interactions of the microwave beam with the atmosphere, the ionosphere and the space plasmas

- safety measures

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Actions in progress about a White Actions in progress about a White Paper on:Paper on:

Wireless communication and Wireless communication and healthhealth