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Algorytmika wyznaczania względnej pozycji łazików marsjańskich

Kotlarz J., Zalewska N.

Pomiary Automatyka Robotyka

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2015

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R. 19, nr 4

43--53

PL

W artykule przedstawiono rozwój metod nawigacyjnych w kolejnych misjach marsjańskich ZSRR, UE i USA oraz opisano najważniejsze algorytmy wyznaczania względnej pozycji na podstawie analizy zdjęć panchromatycznych rejestrowanych przez współczesne łaziki i zdjęć wykonanych przez satelity znajdujące się na orbicie Czerwonej Planety. Zaprezentowane wnioski mogą służyć jako wskazówki do wypracowania założeń i warunków przeprowadzenia eksperymentu użycia wybranych algorytmów na łaziku lub komputerze dowolnej platformy wielosensorowej.

EN

The current European Space Agency space programs assume the use of autonomous, mobile, equipped with advanced scientific instruments rovers on the Moon and Mars surfaces. Precise determination of position and orientation is one of the most important skills in such programs. During succesive missions a number of image-processing algorithms for determining rover position were developed. The results showed that the algorithm able to determine precisely position in any type of a terrain and for any kind of conditions does not exist. Scientists and engineers from ESA’s ESTEC are have been carrying out works on two different directions of algorithms development. First: algorithm that will be applicable to most of conditions on Mars, second: development of previous algorithms results validation methods (cross-validation, perhaps). In this paper we present navigation techniques in past Russian, European and US missions to the Mars and the most important image-processing algorithms for determining rover position. Our conclusions can be used as a guide for assumptions and conditions of the autonomous navigation experiment design.

2

Spectra of light absorption by phytoplankton pigments in the Baltic; conclusions to be drawn from a Gaussian analysis of empirical data

Ficek D., Kaczmarek S., Stoń-Egiert J., Woźniak B., Majchrowski R., Dera J.

Oceanologia

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2004

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No. 46 (4)

533-555

EN

Analysed by differential spectroscopy, 1208 empirical spectra of light absorption apl(?) by Baltic phytoplankton were spectrally decomposed into 26 elementary Gaussian component bands. At the same time the composition and concentrations of each of the 5 main groups of pigments (chlorophylls a, chlorophylls b, chlorophylls c, photosynthetic carotenoids and photoprotecting carotenoids) were analysed in 782 samples by HPLC. Inspection of the correlations between the intensities of the 26 elementary absorption bands and the concentrations of the pigment groups resulted in given elementary bands being attributed to particular pigment groups and the spectra of the mass-specific absorption coefficients established for these pigment groups. Moreover, balancing the absorption effects due to these 5 pigment groups against the overall absorption spectra of phytoplankton suggested the presence of a sixth group of pigments, as yet unidentified (UP), undetected by HPLC. A preliminary mathematical description of the spectral absorption properties of these UP was established. Like some forms of phycobilins, these pigments are strong absorbers in the 450-650 nm spectral region. The packaging effect of pigments in Baltic phytoplankton was analysed statistically, then correlated with the concentration of chlorophyll a in Baltic water. As a result, a Baltic version of the algorithm of light absorption by phytoplankton could be developed. This algorithm can be applied to estimate overall phytoplankton absorption spectra and their components due to the various groups of pigments from a knowledge of their concentrations in Baltic water.

3

Modelling light and photosynthesis in the marine environment

Woźniak B., Dera J., Ficek D., Majchrowski R., Ostrowska M., Kaczmarek S.

Oceanologia

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2003

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No. 45 (2)

171-245

EN

The overriding and far-reaching aim of our work has been to achieve a good understanding of the processes of light interaction with phytoplankton in the sea and to develop an innovative physical model of photosynthesis in the marine environment, suitable for the remote sensing of marine primary production. Unlike previous models, the present one takes greater account of the complexity of the physiological processes in phytoplankton. We have focused in particular on photophysiological processes, which are governed directly or indirectly by light energy, or in which light, besides the nutrient content in and the temperature of seawater, is one of the principal limiting factors. To achieve this aim we have carried out comprehensive statistical analyses of the natural variability of the main photophysiological properties of phytoplankton and their links with the principal abiotic factors in the sea. These analyses have made use of extensive empirical data gathered in a wide diversity of seas and oceans by Polish and Russian teams as well as by joint Polish-Russian expeditions. Data sets available on the Internet have also been applied. As a result, a set of more or less complex, semi-empirical models of light-stimulated processes occurring in marine phytoplankton cells has been developed. The trophic type of sea, photo-acclimation and the production of photoprotecting carotenoids, chromatic acclimation and the production of various forms of chlorophyll-antennas and photosynthetic carotenoids, cell adaptation by the package effect, light absorption, photosynthesis, photoinhibition, the fluorescence effect, and the activation of PS2 centres are all considered in the models. These take into account not only the influence of light, but also, indirectly, that of the vertical mixing of water; in the case of photosynthesis, the quantum yield has been also formulated as being dependent on the nutrient concentrations and the temperature of seawater. The bio-optical spectral models of irradiance transmittance in case 1 oceanic waters and case 2 Baltic waters, developed earlier, also are described in this paper. The development of the models presented here is not yet complete and they all need continual improvement. Nevertheless, we have used them on a preliminary basis for calculating various photosynthetic characteristics at different depths in the sea, such as the concentration of chlorophyll and other pigments, and primary production. The practical algorithm we have constructed allows the vertical distribution of these characteristics to be determined from three input data: chlorophyll a concentration, irradiance, and temperature at the sea surface. Since all three data can be measured remotely, our algorithm can be applied as the "marine part" of the remote sensing algorithms used for detecting marine photosynthesis.