The research area is located in the Ina Valley of the West Pomeranian Voivods hip, along the border between two counties Choszczno and Stargard. The majority of this area is covered by the largest wetland in Western Pomerania, which is under legal protection. The aim of the study was to identify chemical properties and typological variability of organic soils of the Ina Valley. On the basis of field studies, four sites that were characterised by the main soil types occurring on the study area were designated. By the river bed, a narrow strip of alluvial, clay-organic sediments was found, from which muddy-gley soils developed. The largest part of the central valley was composed of organic low moor peat deposits, from which organic fibric-muck soils, in the third degree of decomposition, evolved. The edge of the valley, on shallow organic sediments, was covered by highly decomposed organic sapricmuck and mucky soils. The richest resources of organic matter were recorded in fibric-muck soils and the poorest in muddy-gley soils. The reaction of soils derived from peat was slightly acid or neutral and alkaline for alluvial deposits. All examined soils were characterised by a very low content of available phosphorus and potassium whereas the amount of available magnesium varied, depending on the soil subtype. Very low concentrations of available magnesium were obtained in sapric-muck and mucky soils, medium in muddy gley soils and high or very high in fibric-muck soils. Total forms of microelements were present in considerable quantities and a very high share of available potassium, magnesium, calcium and sodium in relation to total forms, in fibric-muck soil, attracts attention. In the case of other soil subtypes, only a high share of available calcium is observed.
Precise Point Positioning (PPP) is a technique used to determine the position of receiver antenna without communication with the reference station. It may be an alternative solution to differential measurements, where maintaining a connection with a single RTK station or a regional network of reference stations RTN is necessary. This situation is especially common in areas with poorly developed infrastructure of ground stations. A lot of research conducted so far on the use of the PPP technique has been concerned about the development of entire day observation sessions. However, this paper presents the results of a comparative analysis of accuracy of absolute determination of position from observations which last between 1 to 7 hours with the use of four permanent services which execute calculations with PPP technique such as: Automatic Precise Positioning Service (APPS), Canadian Spatial Reference System Precise Point Positioning (CSRS-PPP), GNSS Analysis and Positioning Software (GAPS) and magicPPP - Precise Point Positioning Solution (magicGNSS). On the basis of acquired results of measurements, it can be concluded that at least two-hour long measurements allow acquiring an absolute position with an accuracy of 2-4 cm. An evaluation of the impact on the accuracy of simultaneous positioning of three points test network on the change of the horizontal distance and the relative height difference between measured triangle vertices was also conducted. Distances and relative height differences between points of the triangular test network measured with a laser station Leica TDRA6000 were adopted as references. The analyses of results show that at least two hours long measurement sessions can be used to determine the horizontal distance or the difference in height with an accuracy of 1-2 cm. Rapid products employed in calculations conducted with PPP technique reached the accuracy of determining coordinates on a close level as in elaborations which employ Final products.
In navigation practice, there are various navigational architecture and integration strategies of measuring instruments that affect the choice of the Kalman filtering algorithm. The analysis of different methods of Kalman filtration and associated smoothers applied in object tracing was made on the grounds of simulation tests of algorithms designed and presented in this paper. EKF (Extended Kalman Filter) filter based on approximation with (jacobians) partial derivations and derivative-free filters like UKF (Unscented Kalman Filter) and CDKF (Central Difference Kalman Filter) were implemented in comparison. For each method of filtration, appropriate smoothers EKS (Extended Kalman Smoother), UKS (Unscented Kalman Smoother) and CDKS (Central Difference Kalman Smoother) were presented as well. Algorithms performance is discussed on the theoretical base and simulation results of two cases are presented.