Martti Hallikainen

Aalto University · Department of Electronics and Nanoengineering

The IEEE Geoscience and Remote Sensing Society’s (GRSS’s) 2018 publications, symposium, and special awards were presented at the IEEE International Geoscience and Remote Sensing Symposium (IGARSS) awards banquet on 26 July at the Hemisferic (Figure 1) in the City of Arts and Sciences, an entertainment-based cultural and architectural complex in Val...

Presents information on the IGARSS Conference held in Valencia, Spain.

Presents the recipients of various GRSS awards that were presented at the 2018 IGARSS Conference.

Several awards were presented on July 26, 2018 during the Banquet of IEEE IGARSS 2018 (International Geoscience and Remote Sensing Symposium) in Valencia, Spain.

The estimation of chlorophyll-a (chl-a) concentration remains a great challenge in turbid waters due to their complex optical conditions. To improve chl-a estimation, this study aims to determine whether combined use of polarimetric synthetic-aperture radar (SAR) data has potential for improving the chl-a estimation from hyperspectral sensing refle...

Remote sensing is a fairly new method for large-scale monitoring of the Earth’s surface; it improves the limited representativeness of traditional point-wise in situ measurements, allowing quantitative analysis of land surface parameters. Especially for snow parameters, its high temporal and spatial coverage make remote sensing the only practical m...

The IEEE Geoscience and Remote Sensing Society’s 2017 Publications Awards were presented at the IGARSS Awards Banquet held on July 27 at the AT&T Stadium in Arlington, Texas. The winning papers in each category and ˗ as a new feature ˗ four honorable mentions are listed.

Presents information on the IGARSS 2017 conference.

Presents the recipients of GRSS society awards presented at the IGARSS 2017 Conference.

Presents a call for nominations for select GRSS awards for 2018.

This letter proposes a novel way to assimilate synthetic aperture radar (SAR) data to L-band Microwave Emission of the Biosphere (L-MEB) model to enhance model performance over forested areas. L- and C-band satellite SAR data are used in order to characterize the forest transmissivity within the emission model, instead of the optical satellite imag...

The papers in this special section were presented at the 14th Specialist Meeting on Microwave Radiometry and Remote Sensing of the Environment (MicroRad 2016) that was held on April 11–14, 2016, on Aalto University Campus, Espoo, Finland. MicroRad is a unique gathering, where the microwave radiometry community has an opportunity to present new desi...

This paper presents a novel method to determine the phase shift of a phase retardation plate. Primarily, the method has been developed for fully polarimetric calibration standards, which consist of a linearly polarized (tripolarimetric) calibration reference and a retardation plate. However, the method can also be applied to phase retardation plate...

A concentric raised bog is a common mire type in the southern boreal zone. The mires play an important role in the hydrological cycle of the environment, as their moisture is usually significantly different from open agricultural land or forest. The hydrological parameters, such as soil moisture (SM), are increasingly assessed by means of remote se...

Coarse ground resolution limits the accuracy of current passive L-band satellite missions for soil moisture retrieval such as soil moisture and ocean salinity and soil moisture active and passive, as many of their pixels contain different land cover types. One of the significant uncertainty factors is introduced by dense vegetation, especially in a...

Presents information on the 2017 IGARSS conference.

Presents the recipients of GRSS awards that were awarded at the IGARSS 2016 conference.

Presents information on the MicroRad 2016 conference.

This paper presents a novel method to determine the phase shift of a phase retardation plate. Primarily, the method has been developed for fully polarimetric calibration standards, which consists of a linearly polarized (tri-polarimetric) calibration standard and a retardation plate. However, the method can also be applied for the phase retardation...

We have conducted a multiyear airborne multifrequency microwave radiometer data collection program over a test site comprising two lakes and adjacent land areas in southern Finland. A variety of snow and ice conditions were encountered, covering early winter, mid-winter, and late winter conditions, and the melting season. A semi-empirical radiative...

We have compared theoretical 37 GHz and 16.5 GHz vertically polarized brightness temperatures (incidence angle 50 degrees off nadir) with experimental time series data obtained over a 26-hr period in an extensive ground-based experiment in southern Finland. During the 26-hr monitoring effort, the snowpack included a variety of dry and wet snow laye...

Boreal coniferous forests are a large and diverse biome, which has not been widely studied in scope of space borne soil moisture (SM) observations. This paper presents a series of airborne measurements that were made to explore microwave emissivity of a boreal coniferous forest in different moisture conditions. Ground observations of SM and vegetat...

Satellite-based snow-cover monitoring is performed using optical, synthetic aperture radar (SAR), and passivemicrowave sensors. Effects of forest canopy on the observed signal need to be considered with all of these sensor types. Various models describing the interaction of electromagnetic radiation with forest canopy have been developed, but many...

Presents the recipients of GRSS Publications Awards and Special Awards that were presented at the IGARSS 2015 conference.

Presents a call for nominations for select 2016 GRSS awards.

Rapid development of Earth Observation technology and increasing awareness of global challenges has increased the need for lean and agile space missions and calls for a new generation of engineers to design them. Miniaturization of sensor technology and electronics has decreased the weight of a satellite, which has brought launch prices to the reac...

At northern latitudes, it is not uncommon for a melting layer of precipitation to touch or be close to the ground. For a low elevation angle, radio waves from a surveillance weather radar scan can travel a long distance through a melting layer. The resulting attenuation can be significant and must be taken into account when radar observations are i...

The Helsinki University of Technology (HUT) snow emission model forms the basis of the European Space Agency's GlobSnow snow water equivalent (SWE) product (Takala et al., 2011). The model applies a semi-empirical radiative transfer calculation to account for the interaction of the snow medium with microwaves; separate components are applied to acc...

Methods for retrieval of the water equivalent of snow on terrain are mostly based on using space-borne Ku and Ka band microwave radiometer data [1]. Retrieval is only possible when snow cover is dry. In northern lake-rich regions the effect of lakes and, additionally, other land-use categories to the brightness temperature leads to the mixed-pixel...

Methods for retrieval of the water equivalent of snow on terrain are mostly based on using space-borne Ku and Ka band microwave radiometer data [1]. Retrieval is only possible when snow cover is dry. In northern lake-rich regions the effect of lakes and, additionally, other land-use categories to the brightness temperature leads to the mixed-pixel...

European Space Agency's SMOS mission delivers global maps of soil moisture, an important parameter in research of the Earths hydrosphere. The relatively coarse surface resolution of SMOS causes the pixels to cover several different types of soil and vegetation, and in order to reliably retrieve soil moisture it is vital to know the properties of al...

We have conducted airborne microwave radiometer campaigns over a test site consisting of two lakes and their immediate surroundings in Southern Finland since 2004 in order to (1) determine the effect of snow cover to the brightness temperature of lake ice, and to (2) compare the brightness temperatures for snow-covered lake ice and snow-covered ter...

The launch of the SMOS mission 2-Nov-2009 marked a milestone in remote sensing for it was the first time a radiometer capable of acquiring wide field of view images at every single snapshot, a unique feature of the synthetic aperture technique, made it to space. The technology behind such an achievement was developed thanks to the effort of a commu...

Small-scale variability in land cover influences both the snow cover and the microwave response of a snow-covered surface. Since low microwave frequencies penetrate below the snowpack, the differing dielectric properties of soil and water have a significant effect on passive microwave observations and therefore cause errors in the interpretation of...

This paper presents an overview and the current status of hosting the electrostatic plasma brake (EPB) experiment on-board the Finnish Aalto-1 satellite. The goal of the experiment is to demonstrate the use of an electrostatically charged tether for satellite attitude and orbital maneuvers. The plasma brake device is based on electrostatic solar sa...

Permittivity characterizes the electrical properties of materials:The real part gives the contrast with respect to vacuum and the imaginary part gives the electromagnetic loss of the material. Loss tangent is defined as the imaginary part divided by the real part of permittivity. Total electromagnetic loss in a medium consists of absorption loss (e...

Lists the recipients of awards presented at theIGARSS 2013 Banquet.

T he IEEE Geoscience and Remote Sensing Society’s 2013 Publications Awards were presented at the IGARSS Awards Banquet on Thursday, July 25 at the Plaza Ballroom. Situated in the heart of Collins Street at Melbourne’s famous Regent Theatre, the prestigious Plaza Ballroom is reminiscent of the grand European ballrooms of the 19th Century. Built in 1...

The URSI Commission F Microwave Signatures 2013 Symposium is the 11th of a series of meetings held in Berne, Switzerland (1974), Lawrence, Kansas (1981 and 1994), Toulouse, France (1984), Göteborg, Sweden (1987), Hyannis, Massachusetts (1990), Igls, Austria (1992), Boulder, Colorado (2001), Ispra, Italy (2005), and Florence, Italy (2010). The meeti...

Presents the recipients of selected GRS society awards.

In this study we investigate pine forest backscattering in L-band by using a coherent field scattering model. We generate multilook data by a novel method for a realistic Scots Pine cylinder model and take a closer look at the probability density functions of the scattering. Multilook data are generated by rotating the tree model randomly around it...

This paper discusses the possibility to use spaceborne X-band radar interferometry for forest height mapping. In our previous works was shown that airborne X-band SAR interferometry combined with accurate ground elevation model can provide good estimates of boreal forest height. In order to apply this technique to spaceborne SAR images, temporal va...

This work presents the outline and so far completed design of the Aalto-1 science mission. Aalto-1 is a multi-payload remote-sensing nanosatellite, built almost entirely by students. The satellite aims for a 500–900 km sun-synchronous orbit and includes an accurate attitude dynamics and control unit, a UHF/VHF housekeeping and S-band data links, an...

GPS receivers are increasingly used in nanosatellite applications to provide the means for autonomous and accurate navigation in orbit. However, many of the available nanosatellite GPS receivers consume a large amount of power compared to the available power budget. This can be a problem when the main science instruments have high power requirement...

This paper evaluates performance of fully polarimetric SAR (PolSAR) data in several land cover mapping studies in the boreal forest environment, taking advantage of the high canopy penetration capability at L-band. The studies included multiclass land cover mapping, forest–nonforest delineation, and classification of soil type under vegetation. Pol...

This paper presents a morphological database, aimed to be applied as boundary data for atmospheric modeling. The database has been created from freely available sources and 13 ASAR images that were provided by European Space Agency (ESA) through Announcement of Opportunity (AO). Urban themes were extracted from optical data and digital maps by supe...

This work presents the outline and so far completed design of the Aalto-1 science mission. Aalto-1 is a multi-payload remote sensing nanosatellite, built almost entirely by students. The satellite aims for a 500–900 km sun-synchronous orbit, and includes an accurate attitude dynamics and control unit, a UHF/VHF housekeeping and S-band data links, a...

Scattering phase center (SPC) location in boreal forests was studied in order to assist forest inventory with single- and quad-pol synthetic aperture radar (SAR) interferometry. Airborne X- and L-band interferometric SAR data collected by the DLR E-SAR instrument in southern Finland during the FINSAR campaign was used in the study. A simple Random...

The paper describes evaluating the potential of peatland detection under forest canopy with L-band space borne quad-polarization data in the boreal forest zone. Particular emphasis was made on under what seasonal conditions this detection was possible using single SAR data-take. For this purpose multitemporal ALOS PALSAR imagery acquired over Kuort...

The paper describes algorithm development for tree height retrieval in the boreal forest zone from TanDEM-X interferometric imagery. A set of 8 TanDEM-X pairs was acquired during summer and autumn 2011 over southern Finland in order to evaluate the potential tree height retrieval performance for this space-borne instrument. Another focus of the stu...

The Soil Moisture and Ocean Salinity (SMOS) mission delivers global surface soil moisture measurements at high temporal resolution, utilizing microwave brightness temperature observations. Retrieval of the soil moisture from measurements over large areas with a vast array of different soils and land usages requires sophisticated algorithms and emis...

Airborne microwave radiometer measurements of lake ice have been performed in 2004, 2007, 2011, and 2012 over two lakes in southern Finland using radiometer systems that cover frequencies from 1.4 to 36.5 GHz. Airborne and surface data have been collected under circumstances ranging from early winter dry snow to late winter dry and wet snow conditi...

In this study we have examined the identification of polynyas in the Kara Sea region with AMSR-E radiometer data. We have utilized a threshold value of the spectral gradient of vertically polarized brightness temperatures between frequencies 89 GHz and 36 GHz. As a comparison, ice thickness defined from the surface temperature measured with MODIS,...

In this paper, we present an analysis of the radiometric performance of the three 1.4-GHz noise injection radiometers of the European Space Agency's Soil Moisture and Ocean Salinity (SMOS) satellite. The units measure the antenna temperature, which contributes to the average brightness temperature level of SMOS retrievals. We assess the radiometric...

L-band radiometry is widely considered the best technique for Earth observing satellites to measure sea surface salinity (SSS). Interferometric aperture synthesis is a new technology applicable in spaceborne remote sensing at low frequencies. The challenge of the technology comes with decreased radiometric resolution and complexity in calibration c...

A functional test to verify the proper and accurate measurement capability of an L-band fully polarimetric noise injection radiometer is presented. The test is designed specifically for the MDPP-2 (MIRAS Demonstrator Pilot Project 2) NIR (Noise Injection Radiometer), which has two functions: (1) to calibrate the MIRAS (Microwave Imaging Radiometer...

A modified approach to realise a cold reference for radiometer calibration is presented. A common problem with the cold references used in radiometer calibration is the temperature distribution of the connection cable between the load and the receiver. The introduced approach utilises the thermodynamical fact that the temperature distribution betwe...

The Electric Solar Wind Sail (E-sail) is a novel propulsion concept that enables faster space travel to many solar system targets. E-sail uses charged solar wind particles as the source of its propulsion. This is achieved by deploying long, conducting and charged tethers, which get pushed by the solar wind by Coulomb drag [1]. E-sail technology is...

This paper introduces the Aalto-1 remote sensing nanosatellite, which is being built under the coordination of The Department of Radio Science and Engineering of Aalto University School of Electrical Engineering. The satellite is a three unit CubeSat, and it will be mostly built by students. The satellite platform is designed to house several paylo...

The launch of the European Space Agency's (ESA) Soil Moisture and Ocean Salinity (SMOS) satellite in November 2009 opened a new era in monitoring globally and continuously these two environmental parameters. The importance of these measurements to provide information on Earth's climate and its changes has been pointed out by the scientific communit...

In this paper we describe the Finnish Earth Observation nanosatallite project Aalto-1. The Aalto-1 i sa4k g student satellite, based on CubeSat standards. The satellite is designed to carry the world’s smallest remote sensing imaging spectrometer for Earth Observation and several other payloads.

Annually large areas of northern hemisphere freeze and are covered with snow. This paper presents results from synthetic aperture radiometer measurements of soils in unfrozen and frozen state and examines changes in their L-band emissivity.

The melting layer attenuation is studied by fitting the modeled reflectivity factor and the reflectivity-weighted fall velocity to measured values at both Ku- and Kabands. In the fitting process the optimized snow density and velocity parameters are defined and the dependence of the modeled attenuation on these parameters is investigated. The study...

Airborne microwave radiometer measurements of lake ice have been performed in 2004, 2007, and 2011 in southern Finland. The HUTRAD radiometer system provided data in the 6.9 to 36.5 GHz range using an incidence angle of 50 degrees off nadir. In 2011 also the interferometric HUT-2D radiometer was used to provide 1.4 GHz imagery of lake ice. Index Te...

This paper discusses the development of the airborne synthetic aperture radiometer HUT-2D of Aalto University. We present the life cycle of the project starting from its initiation, highlighting the main milestones and achievements in hardware development, interferometric algorithm validation, and finally in airborne campaigns. We point out the mos...

This paper describes the analysis of L-band radiometric measurement data gathered with the synthetic aperture radiometer HUT-2D during several ground-based and airborne measurement campaigns. The radiometric data are analyzed from the instrument's performance point of view, aiming to verify the theoretical performance of an instrument of this kind...