Preface

Being a vital modern technology, satellite systems for navigation, telecommunication, and geosciences have developed rapidly in the last 25 years. In fact, we are on the verge of a massive explosion of new markets for GNSS and associated position determination applications. Plans for GNSS modernization are well advanced and will enable unprecedented positioning accuracy, signals availability, and greater system integrity over the globe. Currently, GNSS technologies have been accepted worldwide as an effective, accurate, and free tool for the geosciences. Numerous research projects have been realized in such vital areas and forms as GNSS-remote sensing (ionosphere and upper atmosphere), GNSS-Reflectometry (GNSS-R) and Satellite Altimetry (SA) (the soil moisture distribution, geodynamics and oceanic surface characteristics), and GNSS-Radio Occultation (GNSS-RO) for the atmospheric sciences.

Considering modern satellite technologies, we face the situation of "head and tail of the one medal". On the one hand the Earth ionosphere, multipath phenomena, and space weather impacts (such as solar radio flares and solar irradiation fluxes) have been the main challenge for all modern satellite-based technologies including GNSS and Low-Earth Orbit (LEO) constellations. It is well known that rapid fluctuations of a signal phase and amplitude fading (ionosphere scintillations), a signal envelope distortion due to multipath as well as powerful solar irradiation impacts, degrade the satellite systems performance. To achieve the highest quality of a satellite system we need to focus on the system robustness regarding the above-mentioned impacts. Modeling and theoretical analysis of scintillations appearance, multipath sources, and solar irradiation impact are the base of every solution to improve the performance of the satellite system for both practice and geosciences. On the other hand the satellite system reaction as a result of the scintillation, multipath, or solar irradiation impacts, may be considered to be very informative and promising way to obtain valuable information for research in geosciences.

And finally, we should bear in mind that all the GNSS-R, GNSS-RO, and SA research technologies are realized based on not only GNSS constellations but also on the variety of LEO satellites. The main value of these technologies is the great opportunities to obtain the characteristics of the Earth atmosphere, ionosphere, and Earth surface over the oceans and long-distant unpopulated territories with high accuracy and resolution. Modern advances in microelectronics, materials, combined with affordable and frequent launch opportunities, have led to a revolution which consists of small LEO satellite missions used for Earth observation and Space exploration. Small satellites are now being developed in large volumes for mega-constellations for Earth observation and low latency communications, thus democratizing space and making new space applications for both practice and geoscience a reality.

In summary, we can say that modern satellite technologies have become a base of our civilization and support our day-to-day activity in both practice and geosciences. This book is devoted to GNSS-remote sensing for ionosphere research, modeling and mitigation techniques to diminish the ionosphere and multipath

**II**

**Section 3**

Applications

*by Adriano Camps*

Satellites Missions and Technologies **105**

**Chapter 7 107**

**Chapter 8 123**

**Chapter 9 145**

Earth Observation Technologies: Low-End-Market Disruptive Innovation

*Steve Edmondson, Sarah Haigh, Nicholas H. Crisp, Vitor T.A. Oiko, Rachel E. Lyons, Stephen D. Worral, Sabrina Livadiotti, Claire Huyton,* 

*Francesco Romano, Yung-An Chan, Adam Boxberger, Stefanos Fasoulas, Constantin Traub, Victor Jungnell, Kristian Bay, Jonas Morsbøl,* 

A Survey on Small Satellite Technologies and Space Missions for Geodetic

Nanosatellites and Applications to Commercial and Scientific Missions

*Luciana A. Sinpetru, Rosa M. Domínguez, David González,* 

*by Silvia Rodriguez-Donaire, Miquel Sureda, Daniel Garcia-Almiñana, Eloi Sierra, Jose S. Perez, Peter C.E. Roberts, Jonathan Becedas, Georg H. Herdrich, Dhiren Kataria, Ronald Outlaw, Leonardo Ghizoni, Rachel Villain, Alexis Conte, Badia Belkouchi, Kate Smith,* 

*Ameli Schwalber and Barbara Heißerer*

*by Vaios Lappas and Vassilis Kostopoulos*

impacts on GNSS, and survey of the modern satellite missions and technologies. We hope that the experts' opinions presented in the book will be interesting for the research community and students in the area of satellites and space missions as well as in engineering and geoscience research.

> **Vladislav Demyanov** Irkutsk State Transport University, Russia

> > Section 1

GNSS-Remote Sensing

for Ionosphere Research

Section 1
