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    Mikrometer-präzise Entfernungsbestimmung mit mehrkanaligen FMCW-Radaren basierend auf kommerziellen Sendeempfängern
    (2026)
    Wenzel, Marvin
    ;
    Kölpin, Alexander
    The present dissertation „Mikrometer-präzise Entfernungsbestimmung mit mehrkanaligen FMCW-Radaren basierend auf kommerziellen Sendeempfängern“ highlights the mathematical and technical foundations of high-precision FMCW-radars and in particular addresses limiting factors of the hardware, algorithms and environment. The designed demonstrator shows that accuracies better than 50 µm in range estimation and smaller than 0,5 degree in angle estimation can be achieved even with low-cost commercial hardware.
    Publicationtype: Doctoral Thesis
      40  23
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    Sensorfusion für das robuste und kontaktlose Monitoring der Vitalparameter von Frühgeborenen auf der neonatologischen Intensivstation
    (2025)
    Gleichauf, Johanna
    ;
    Kölpin, Alexander
    The current monitoring of vital signs of preterm neonates bears the risk to injure the little patients. Therefor, the question arises if it is possible to determine the vital parameters of neonates and preterm neonates precisely and robustly via non-contact methods. A non-contact system was developed for monitoring the respiratory and heart rates as well as the core temperature of the neonates. Different sensors such as an RGB camera, a thermal camera, several time-of-flight cameras and a radar sensor are combined or their data are fused. The region of interest detected by each sensor is automatically determined by a neural network (YOLOv3) which was trained with fused images. The necessary algorithms to calculate the vital parameters were developed or existing algorithms improved. The best approach found during the validation phase is the evaluation of ToF camera data for determining the respiratory rate and the temperature detection via thermal camera with reference temperature sensor. The evaluation of the heart rate using an RGB camera does not deliver the clinical necessary precision. It was shown that under optimal conditions a non-contact detection of the respiratory rate and the body temperature is possible with good results.
    Publicationtype: Doctoral Thesis
      54  40
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    Item type:Publication, Access status: with files ,
    Identifikation, Auswirkung und Simulation von Wellenausbreitungseffekten in der Zug-Onboard-Kommunikation mithilfe realer Kanalcharakterisierung
    (2024)
    Lichtblau, Johann
    ;
    Kölpin, Alexander
    This thesis discusses the challenges of wireless train onboard communication in 5G frequencies below 6 GHz based on channel measurements in rail traffic. The typical wave propagation effects are identified, their impact is discussed and simulations are carried out on the basis of developed channel models. Theoretical considerations in combination with numerous empirical data reduce the significant research gap in train onboard communication and form the basis for the design of future communication systems in rail transport. Furthermore, the findings of the channel characterization are linked to the relevant standards in rail transport, from which the feasibility of safety-critical functions can be evaluated using wireless communication.
    Publicationtype: Doctoral Thesis
      87  107
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    Langzeit-Funklokalisierungsverfahren mit extrem energieeffizienten, miniaturisierten Mobilfunkloggern
    (2022)
    Erhardt, Stefan
    ;
    Kölpin, Alexander
    In the area of wildlife and species conservation and ecology, movement profiles are an important method for spatial and behavioral analyses. Research on the movement behavior of bats imposes high technical demands on appropriate tracking systems. The low weight and the photophobic behavior of European species implies a resource limitation and the necessity to have the energy required for the entire run time from the very beginning, since energy harvesting (e.g. with solar cells) is not feasible. In recent years, several radio localization systems specifically tailored to bats have been published, which can be used to record precise flight movements and the social and hunting behavior of the animals. However, due to their functional principle, only limited ranges and run times can be realized, which makes them unsuitable for long-range migration analyses. This thesis introduces a novel radio localization method for bat migration analysis that, for the first time, provides position records with consistently high temporal resolution over one migration periode. The method is based on the detection of cellular base stations, whose locations are known a priori and which are used for position estimation. A key point of this work is the system design of a miniaturized cellular logger, which was realized as a software defined radio consisting of an integrated sub-GHz transceiver and an ARM Cortex-M4 microcontroller. For this purpose, a GSM stack optimized for real-time capability was implemented to detect GSM cells in the 900 MHz band and decode their BCCH. In addition to supplementary acceleration and temperature sensing, the logger has a functionality for recovery and data download via an 868 MHz radio interface. Ruggedly constructed with a fiber composite, the logger has a weight of 2.0 g with the form factor of a 1 Eurocent coin and achieved a measurement lifetime of 11.2 months with four measurements per day. The system was successfully deployed on bats in several field tests. For a two-week short-term deployment with a measurement interval of 10 minutes, the loggers were glued to animals of the species greater mouse-eared bats (Myotis myotis). The recorded data could be downloaded daily by radio in the roost and the movement behavior of the nocturnal excursions could be analyzed. For long-term migration analysis, the loggers were sutured to the skin of common noctules (Nyctalus noctula) and took four measurements per day. This method of attachment, which has been rarely used before, turned out to be insufficient, so only one logger could be recovered. However, its migration behavior could be reconstructed in detail with a previously unreached resolution.
    Publicationtype: Doctoral Thesis
      233  1341
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    Development of a highly integrated and radiation-tolerant software-defined radio platform for multi-band radio applications in space systems
    (2021-08-31)
    Budroweit, Jan
    ;
    Kölpin, Alexander
    The present thesis deals with the design of a highly integrated and radiation tolerant software-defined radio (SDR) platform for multi-channel radio applications in space systems. The described design addresses the risk-minimized use of non-space qualified electronic components for critical space systems, which is ultimately used for the development and verification of the innovative SDR platform presented in this work.
    Publicationtype: Doctoral Thesis
      495  1271
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      106
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      74