
Markku PoutanenFinnish Geospatial Research Institute · Geodesy and Geodynamics
Markku Poutanen
Prof., PhD
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Introduction
Skills and Expertise
Publications
Publications (240)
An ideal target for geodetic very long baseline interferometry (VLBI) is a strong and point-like radio source. In reality, most celestial sources used in geodetic VLBI have spatial structure. This is as a major source of error in VLBI Global Observing System (VGOS) and also affects legacy S/X observations. Source structure causes a systematic delay...
Metsähovi Geodetic Research Station (MGRS) of the National Land Survey of Finland, has undergone a major upgrade. The first observations at MGRS were started in 1978. A decade-long reform began in 2012, during which all major systems were renewed. This included Global Navigation Satellite System (GNSS) station, Satellite Laser Ranging (SLR) system,...
Context. The Carte du Ciel archive at the University of Helsinki enables us to see the sky as it was about 120 yr ago. The archive consists of single-exposure and triple-exposure plates between epochs 1896.8–1925.8.
Aims. Our main aim is to find binary and multiple stars by combining Carte du Ciel and Gaia data.
Methods. The plates were digitised w...
We provide a survey on the joint European research project “GeoMetre”, which explores novel technologies and their
inclusion to existing surveying strategies to improve the traceability of geodetic reference frames to the SI definition of the
metre. This work includes the development of novel distance meters with a range of up to 5 km, the realisat...
The datum problem is a fundamental issue in the network adjustment when connecting a local measurement network to an external reference frame. Datum elements in 3D networks are scale, translation, and orientation. We consider here the local tie network at geodetic core stations, where the external reference frame is the latest ITRF realization, ITR...
Coastal sea level is observed at tide gauge stations, which usually also serve as height reference stations for national networks. One of the main issues with using tide gauge data for sea level research is that only a few stations are connected to permanent GNSS stations needed to correct for vertical land motion. As a new observation technique, a...
VLBI telescope reference point, the closest point in the telescope primary axis from the secondary axis, is typically determined indirectly by observation of points co-rotating with the telescope. We have previously measured telescope reference point indirectly with two GPS-antennas attached on the edge of the dish of the Aalto University Metsähovi...
Tide gauge (TG) time series and GNSS measurements have become standard datasets for various scientific and practical applications. However, the TG and geodetic networks in the Baltic Sea region are deforming due to vertical land motion (VLM), the primary cause of which is the glacial isostatic adjustment. Consequently, a correction for VLM, either...
Traditionally, sea level is observed at tide gauge stations, which usually also serve as height reference stations for national levelling networks and therefore define a height system of a country. Thus, sea level research across countries is closely linked to height system unification and needs to be regarded jointly. The project aims to make use...
Traditionally, sea level is observed at tide gauge stations, which usually also serve as height reference stations for national leveling networks and therefore define a height system of a country. Thus, sea level research across countries is closely linked to height system unification and needs to be regarded jointly. One of the main deficiencies t...
The next‐generation, broadband geodetic very long baseline interferometry system, named VGOS, is being developed globally with an aim to achieve 1 mm accuracy for station positions. Currently, the systematic errors in VGOS broadband delays are still about 20 ps. In this study, we demonstrate that it is feasible to make images directly from VGOS obs...
Since realising the idea that a man-made object can be intentionally placed into the Earth’s orbit, almost 10,000 satellites have been launched for multiple scientific, commercial and military purposes. These activities produce a huge amount of junk comprised not only of defunct artificial objects that no longer serve a useful purpose, but various...
The tenth launch (L10) of the European Global Navigation Satellite System Galileo filled in all orbital slots in the constellation. The launch carried four Galileo satellites and took place in July 2018. The satellites were declared operational in February 2019. In this study, we report on the performance of the Galileo L10 satellites in terms of o...
On 12 February 2020, the latest four Galileo satellites had completed one full year of space operational service. The satellites were launched on 25 July 2018. The quartet increased the operational capacity of the Galileo constellation to 22 satellites. This study reports on three signal-in-space (SiS) performance indicators - status, availability,...
GIPSY-derived PPP daily Cartesian coordinates at Aboa GPS station station in Dronning Maud Land, East Antarctica and their associated standard deviations and correlations. Please consult the reference manuscript for details about the processing procedure.
Reference:
Andrei et. al (2018): GPS Time Series Analysis from Aboa the Finnish Antarctic Re...
RTKLIB-derived PPP daily Cartesian coordinates at Aboa GPS station in Dronning Maud Land, East Antarctica and their associated standard deviations and correlations. Please consult the reference manuscript for details about the processing procedure.
Reference: Andrei et al. (2018): GPS Time Series Analysis from Aboa the Finnish Antarctic Research S...
Continuous Global Positioning System (GPS) observations have been logged at the Finnish Antarctic research station (Aboa) since February 2003. The station is located in Dronning Maud Land, East Antarctica. Almost 5000 daily observation files have been archived based on yearly scientific expeditions. These files have not been fully analysed until no...
Context . Carte du Ciel was a global international project at the end of the nineteenth and beginning of the twentieth century to map the sky to about magnitude 14 on photographic plates. The full project was never observationally completed and a large fraction of the observations made remain unanalyzed.
Aims . We want to study whether the astromet...
GNSS antennas have no fixed electrical reference point. The variation of the phase centre is modelled and tabulated in antenna calibration tables, which include the offset vector (PCO) and phase centre variation (PCV) for each frequency according to the elevations and azimuths of the incoming signal. Used together, PCV and PCO reduce the phase obse...
We study observations of a fireball that occurred in Kylmälä, Finland with the aim of determining its Keplerian orbital elements. The fb_entry program is used to determine the fireball's trajectory based on the observations. The orbit is then determined using this trajectory as the input parameters with the Meteor Toolkit software. We successfully...
In the preceding chapter we have seen how one can compute the evolution of a star by starting from a homogeneous model representing a newly formed system. When the chemical composition of the star changes with time, a new model is computed each time. In this chapter we shall consider the theoretical evolutionary paths of systems with various masses...
Most astronomical observations utilise electromagnetic radiation in one way or another. We can obtain information on the physical nature of a radiation source by studying the energy distribution of its radiation. We shall now introduce some basic concepts that characterise electromagnetic radiation.
Spherical astronomy is a science studying astronomical coordinate frames, directions and apparent motions of celestial objects, determination of position from astronomical observations, observational errors, etc. We shall concentrate mainly on astronomical coordinates, apparent motions of stars and time reckoning. Also, some of the most important s...
Quite often, two stars may appear to be close together in the sky, although they are really at very different distances. Such chance pairs are called optical binary stars. However, many close pairs of stars really are at the same distance and form a physical system in which two stars are orbiting around each other. Less than half of all stars are s...
In astrophysics those stars in which the density of matter is much larger than in ordinary stars are known as compact objects. These include white dwarfs, neutron stars, and black holes. In addition to a very high density, the compact objects are characterised by the fact that nuclear reactions have completely ceased in their interiors. Consequentl...
The galaxies are the fundamental building blocks of the Universe. Some of them are very simple in structure, containing only normal stars and showing no particular individual features. There are also galaxies that are almost entirely made of neutral gas. On the other hand, others are complex systems, built up from many separate interacting componen...
Is there life elsewhere in the universe? And if there is, are there any intelligent beings? How did life emerge on the Earth, and, as a matter of fact, how do we define life and intelligence? These are probably the most interesting unsolved questions in science. During the last few decades a whole new field of astrobiology has evolved around these...
The Copernican principle means that the Earth has gradually lost its special status: it is just a planet orbiting a relatively common star in an ordinary galaxy. But how common planetary systems are? Nowadays we think that they belong to the normal life of a star. However, it is difficult to make ground based observations of exoplanets, i.e. planet...
Celestial mechanics, the study of motions of celestial bodies, together with spherical astronomy, was the main branch of astronomy until the end of the 19th century, when astrophysics began to evolve rapidly. The primary task of classical celestial mechanics was to explain and predict the motions of planets and their satellites. Several empirical m...
The Sun is our nearest star. It is important for astronomy because many phenomena which can only be studied indirectly in other stars can be directly observed in the Sun (e.g. stellar rotation, starspots, the structure of the stellar surface). Our present picture of the Sun is based both on observations and on theoretical calculations. Some observa...
Several collections of stars can be picked out in the sky, even with the naked eye. Closer study reveals that they really do form separate clusters in space. E.g. the Pleiades in Taurus and the Hyades around Aldebaran, the brightest star in Taurus, are such open star clusters. Almost the whole of the constellation Coma Berenices is also an open sta...
Although most of the mass of the Milky Way Galaxy is condensed into stars, interstellar space is not completely empty. It contains gas and dust in the form both of individual clouds and of a diffuse medium. Interstellar space typically contains about one gas atom per cubic centimetre and 100 dust particles per cubic kilometre.
Our solar system contains eights planets orbiting the Sun, dwarf planets, asteroids, comets and meteors, as well satellites orbiting planets and smaller ring particles. In this chapter the properties of these different object are discussed.
Stars with changing magnitudes are called variables (Fig. 14.1). Variations in the brightness of stars were first noted in Europe at the end of the 16th century, when Tycho Brahe’s supernova lit up (1572) and the regular light variation of the star \(o\) Ceti (Mira) was observed (1596). The number of known variables has grown steadily as observatio...
On clear, moonless nights a nebulous band of light can be seen stretching across the sky. This is the Milky Way (Fig. 18.1). The name is used both for the phenomenon in the sky and for the large stellar system causing it. The Milky Way system is also called the Galaxy—with a capital letter. The general term galaxy is used to refer to the countless...
All our information about the physical properties of stars comes more or less directly from studies of their spectra. In particular, by studying the strength of various absorption lines, stellar masses, temperatures and compositions can be deduced. The line shapes contain detailed information about atmospheric processes.
Cosmology is a science studying the structure and evolution of the whole Universe. Research in cosmology tries to answer questions such as: How large and how old is the Universe? How was it born? How is matter distributed? How were the elements formed? What will be the future of the Universe?
After the demise of the Aristotelian world picture, it t...
Up to the end of the Middle Ages, the most important means of observation in astronomy was the human eye. It was aided by various mechanical devices to measure the positions of celestial bodies in the sky. The telescope was invented in Holland at the beginning of the 17th century, and in 1609 Galileo Galilei made his first astronomical observations...
The solar system consists of a central star, called the Sun, planets orbiting the Sun and several smaller objects. By the solar system we mean here and in the next chapter the system around our own Sun. Also other stars have similar systems. They will be discussed later in Chap. 22. This chapter deals with general properties of the solar system. In...
The stars are huge gas spheres, hundreds of thousands or millions of times more massive than the Earth. A star such as the Sun can go on shining steadily for thousands of millions of years. This is shown by studies of the prehistory of the Earth, which indicate that the energy radiated by the Sun has not changed by much during the last four thousan...
In the previous chapters we have studied the physical properties and detection of electromagnetic radiation. Next we shall briefly discuss concepts related to emission and absorption of radiation. Since we can give here only a summary of some essential results without delving into quantum mechanical explanations, the reader interested in the detail...
On a dark, cloudless night, at a distant location far away from the city lights, the starry sky can be seen in all its splendour (Fig. 1.1). It is easy to understand how these thousands of lights in the sky have affected people throughout the ages. As long as human beings have existed, they have certainly wondered the sky. In the sky, ancient peopl...
The EUREF (Reference Frame Sub-Commission for Europe) Permanent GNSS Network (EPN) serves as the backbone for the realization of, and access to, the European Terrestrial Reference System (ETRS89). The cumulative site positions and velocities for the EPN stations are used for national ETRS89 densifications and geo-information applications. EUREF has...
The Finnish Geospatial Research Institute (FGI) maintains a time series of absolute gravity (AG) measurements in Western and Central Dronning Maud Land, Antarctica. The purpose is to detect the variation in gravity due to the Glacial Isostatic Adjustment (GIA) and to the contemporary changes in regional glacier mass balance. The comparison of gravi...
We provide an overview and present some spectacular examples of the recent meteor observations at the Metsähovi Geodetic Research Station. In conjunction with the Finnish Fireball Network the all-sky images are used to reconstruct atmospheric trajectories and to calculate the pre-impact meteor orbits in the Solar System. In addition, intensive coll...
Stellar occultations by asteroids observed at visual wavelengths have been an important tool for studying the size and shape of asteroids and for revising the orbital parameters of asteroids. At radio frequencies, a shadow of an asteroid on the Earth is dominated by diffraction effects. Here, we show, for the first time, that a single observation o...
After the regional Chinese Beidou Navigation Satellite System (BDS) reached its full configuration of 16 operational BDS navigation satellites in November 2012, China launched the new generation Beidou satellite in March 2015. The purpose is to test new navigation signals and inter-satellite communication links and define the necessary protocols fo...
In southern Tibet, ongoing vertical and horizontal motions due to the collision between India and Eurasia are monitored by large numbers of global positioning system (GPS) continuous and campaign sites installed in the past decade. Displacements measured by GPS usually include tectonic deformation as well as non-tectonic, time-dependent signals. To...
Precise levelling is known for its accuracy and reliability in height determination, but the process itself is slow, laborious and expensive. We have started a project to study methods for height determination that could decrease the creation time of national height systems without losing the accuracy and reliability that is needed for them. In the...
In 2014, Metsähovi Radio Observatory, together with the Finnish Geodetic Institute, have observed six IVS sessions: three T2 and three EUROPE sessions.
Based on the current state of technology, distance measurements over a few hundred metres in air with relative uncertainties significantly better than 10−6 are still an almost impossible challenge. In the European Joint Research Project (JRP) “Metrology for long distance surveying” measurement uncertainties in GNSS-based and optical distance metrol...
The Finnish Geodetic Institute built a modern 5.5m long Michelson-Gale-type water level tilt
meter for the Geodetic and Geophysical Institute of the MTA CSFK. The instrument was installed in
August 2014 in Conrad Geophysical Observatory of the Zentralanstalt für Meteorologie und
Geodynamik, in Thal, Austria. We present the installation of it and...
The land uplift is a well-known process at the coastal areas of the Gulf of Bothnia in Finland and Sweden. Today, about 700 hectares of new land is rising from the sea every year. This is changing the landscape rapidly, especially at the shallow coastlines and archipelago of Kvarken in Finland where during the last century the uplift rate relative...
Very Long Baseline Interferometry (VLBI) is a primary space-geodetic technique for determining precise coordinates on the Earth, for monitoring the variable Earth rotation and orientation with highest precision, and for deriving many other parameters of the Earth system. The International VLBI Service for Geodesy and Astrometry (IVS, http://ivscc.g...
The EUREF (Reference Frame Sub-Commission for Europe) Permanent GNSS Network (EPN) serves as the backbone for the realization of, and access to, the European Terrestrial Reference System (ETRS89). The cumulative site positions and velocities for the EPN stations are used for national ETRS89 densifications and geo-information applications. EUREF has...
In this paper we discuss future, need and structure of the European Combined Geodetic Network ECGN. It aims the integration of time series of spatial/geometric observations obtained from GNSS, physical quantities obtained from gravity field related observations and other parameters including precise levelling, tide gauge records, and earth and ocea...
The EUREF key infrastructures are the EUREF Permanent GNSS Network (EPN) and the Unified European Levelling Network (UELN). The EPN runs almost 250 Global Navigation Satellite System (GNSS) stations in a well organized environment and serves as the backbone of the realization of and access to the European Terrestrial Reference System (ETRS89) and a...
Geodetic observing systems have been planned and developed during the last
decade. An ideal observing system consists of a network of geodetic
observing stations with several techniques at the same site, publicly
accessible databases, and as a product delivers data time series,
combination of techniques or some other results obtained from the data...
In 2013, Metsähovi Radio Observatory, together with Finnish Geodetic Institute, observed seven IVS sessions, five T2 sessions, and two EUROPE sessions. Old analog BBCs and Mark 5A were retired
during the year, and were replaced by a DBBC and a Mark 5B+. In September, Metsähovi participated in
a 4 Gbps e-VLBI demo with a FlexBuff recorder and vlbi s...
In this article we discuss and give an example of three different methods to measure the local tie between the IGS GPS antenna reference point (ARP) and the VLBI antenna reference point at the Metsähovi fundamental station. First we introduce traditional survey approach combined with a space intersection technique and then local tie based on kinema...
In 2012, Metsähovi Radio Observatory together with Finnish Geodetic Institute officially became an IVS Network Station. Eight IVS sessions were observed during the year. Two spacecraft tracking and one EVN X-band experiment were also performed. In 2012, the Metsähovi VLBI equipment was upgraded with a Digital Base Band Converter, a Mark 5B+, a FILA...
Absolute-gravity stations are an important part of the geodetic infrastructure of the Antarctic. They provide accurate starting values for gravity surveys performed e.g. for the determination of the geoid, for geological studies and for geophysical investigations. The time variation in gravity determined from repeated absolute-gravity measurements...
Geodetic observing systems have been planned and developed during the last decade. An ideal observing system consists of a network of geodetic observing stations with several techniques at the same site, publicly accessible databases, and as a product delivers data time series, combination of techniques or some other results obtained from the data...
The IAG Sub-commission 1.3a EUREF is a joint effort of research agencies and National Mapping and Cartographic Agencies with the goal to define, realize and maintain the European Reference Frame. The EUREF key infrastructures are the EPN (EUREF Permanent Network) and the UELN (United European Leveling Network). The EPN runs almost 250 GNSS stations...
The Finnish Geodetic Institute (FGI) is building a new multi-satellite GNSS network in Finland. The renewal of the old GPS-only network FinnRef is funded by the Ministry of Agriculture and Forestry. The new network will consist of 19 stations collecting data from GPS, Glonass, Galileo and later also from Compass satellites. The network stations wil...
The Finnish Geodetic Institute maintains time series of absolute gravity
(AG) and GPS positions in Dronning Maud Land, Antarctica. The AG time
series at the Finnish station Aboa was started in 1994; shorter AG
series were collected by us at Novolazarevskaya and Sanae IV. Aboa has
continuous GPS since 2003; at Sanae IV we rely on the IGS station VES...
We describe the plans for renewal of Metsähovi Fundamental Station
and the GNSS reference network of Finland. During next five years a
total of 8 M Euros are invested to the renewal by the Finnish Geodetic
Institute. This include a new SLR and VLBI2010 compatible radio
telescope, a super conducting gravimeter, and renewal of the reference
GNSS netw...
Space geodesy and space geodetic applications are already so common in our everyday life that we even do not recognise them. Navigation satellites orbiting Earth allow us to measure our position everywhere within metres and applications using this precise positioning information are continuously increasing. Price of a simple navigator is already so...
Traceability is a feature that is required more frequently in local geodetic high-precision measurements. This basic term of metrology, a measurement science, describes the property of a measurement result whereby the result can be related to a reference through a documented unbroken chain of calibrations, each contributing to the measurement uncer...
For the next-generation geodetic VLBI network a 1 mm positioning accuracy is anticipated. The accuracy should be site-independent consistent, reliably controlled, and traceable over long time periods. There are a number of remaining limitations. These include random and systematic components of the delay observable itself, various antenna-related e...
A substantial material flow, deep within the solid Earth, is caused by the periodic ocean-continent water transport of the Quaternary ice ages. That lateral transport is enormous, causing 120–135 m of equivalent global sea-level rise and fall, or about 45–50 Peta tonnes (1 Peta tonne = 1018 kg) of surface mass transfer. The global manifestation of...
The north-west region of the Europe (the Baltic shield) has the well-known phenomena of the postglacial uplift. Parameters of this uplift were evaluated many times in various projects (e.g. Baltic Sea Level, BIFROST), from permanent GPS station data, and by tide gauge recordings and repeated precise levelling. In addition to the general uplift patt...
We introduce a new mathematical model to compute the centering parameters of a VLBI antenna. These include the coordinates of the reference point, axis offset, orientation, and non-perpendicularity of the axes. Using the model we simulated how precisely parameters can be computed in different cases. Based on the simulation we can give some recommen...
A geodetic boundary value problem (GBVP) approach has been formulated which can be used for solving the problem of height datum unification. The developed technique is applied to a test area in Southwest Finland with approximate size of 1.5° × 3° and the bias of the corresponding local height datum (local geoid) with respect to the geoid is compute...
Development of distance measurement instruments based on new technology is advancing.
This increases interest in the best possible testing and validation services in metrology
institutes and among manufacturers of surveying instruments. A recent project to improve the
facilities in Europe, calibration of the new BEV geodetic baseline in Innsbruck,...
The GeoSatakunta GPS network was established in 2003 to obtain information on contemporary crustal deformations in the Satakunta region. The network consists of 13 concrete pillars for episodic GPS campaigns and the Olkiluoto permanent GPS station. The baseline lengths range from five to 65 km. In this study we processed the GPS data of three annua...
The Finnish Geodetic Institute (FGI) has performed GPS measurements in the Satakunta region since the mid-1990s. Crustal deformation studies at Olkiluoto nuclear power station have been conducted since 1995 based on a contract with Posiva Oy. In an area covering a few square kilometres, the accuracy achieved in ten years with semi-annually repeated...