It is a great advantage of gaining knowledge about the environment for navigation. The environment should be measured during the employment as exactly as possible, in order to be able to react correctly. Robots are being used for different tasks at contaminated environments, places in danger or completely safe places. For robotic use, scanning capabilities of the environment are limited at the present. Adhering to the limitations of the scanning systems, the environment is scanned at a particular level and charted with appropriate software. In some cases, this scanning capability is not enough to react correctly. Taking these needs into consideration, this thesis successfully demonstrates the design and implementation of a scanning platform for mobile robotics. A scanning platform with a laser rangefinder scanner will be addressed in a compact design with maximum field of view for quickly mapping and high resolution. With this design, the scanning system will be provided by rotating laser rangefinder at z-axis in one dimension. Laser rangefinder will also measure the distance as the second dimension of the system. Also it rotates the laser beam at another axis which is different from the measuring distance axis and rotary z-axis. In this way, the scanning system will have the three-dimensional scanning ability. This design allows the scanning platform, continuous scanning capability at three dimensional.

In this study, it is aimed to improve the previously developed data acquisition program which was run under DOS and 2D surface reconstruction program under Windows. A new system is set up and both data acquisition and processing software are developed to collect and process data within just one application, running under Windows. The main goal of the thesis is to acquire and process the range data taken from the laser rangefinder in order to construct the 3D image map of simple objects in different positions for indoor environments. The data acquisition program collects data in helical way. To do this, appropriate parameters for the data acquisition interface are determined. In the data processing step, it is aimed to use basic triangulation algorithms and threshold conditions to calculate resolutions, detect noisy points and segment objects from the environment for line fitting. The developed and implemented data acquisition and processing interfaces in the thesis are capable of creating 3D image map and obtaining the view of scanned environment in a short time with high accuracy.

Micro-unmanned aerial rotorcraft are quickly gaining acceptance as indoor platforms for performing stealth, surveillance, and rescue and reconnaissance missions. These rotorcraft are generally required to operate in cluttered, unknown, and dynamic GPS-denied environments, which present threats to the safe operation of the vehicle. To overcome these environmental challenges, we describe a system that is capable of localizing itself by producing accurate odometry estimates that can detect and track moving objects and avoid collisions with obstacles while following a moving target using a laser range finder. Our system has been implemented in the Simulink environment in MATLAB. Various simulations have shown our methods to work well, even in the presence of sensor noise and out-of-plane motion. Our system is capable of localizing itself within ±20 mm in North and East and ±0.5 degrees in ψ while detecting and tracking

Au-delà de son utilisation en géophysique ou en métrologie à grande échelle, la télémétrie laser des longues distances devrait trouver de nombreuses applications pour les missions spatiales. Les instruments d'observation par synthèse ouverture en vols en formation demandent que la géométrie de la constellation soit connue et contrôlée à bien mieux que la longueur d’onde de la fenêtre d’observation. Pour répondre à ces besoins, nous avons étudié un nouveau schéma de mesure qui combine une mesure interférométrique, réalisée sur un faisceau à deux modes et une mesure de temps de vols. Mon travail de thèse a porté sur la conception, mise en œuvre et la caractérisation de la mesure interférométrique. Pour qu'elles ne soient pas affectées par les dérives lentes de l'instrumentation microonde, les deux mesures de phase de longueur d’onde optique (1.55 µm) et de longueur d’onde synthétique (15 mm) sont extraites d'un même signal d’interférence à deux modes en utilisant une procédure de mesure dédiée : on réalise des mesures du signal d’interférence à trois valeurs de la fréquence optique de la source, calculées d'après le résultat de la mesure de temps de vol. Le télémètre met à profit les propriétés du signal d'interférence à deux modes et exploite la phase et l'amplitude du signal à 20 GHz de façon à éliminer les dérives de phase à long terme du signal microonde dans les chaînes de mesure. On peut en attendre, en moins de 0.1 s, une mesure de résolution et d'exactitude inférieures au nanomètre. Le montage expérimental a permis de montrer que le principe de mesure est correct. Sur la mesure d’un chemin optique dans l'air, nous avons obtenu une résolution de 100 pm à 100 µs, qui nous permet d'observer le bruit acoustique. Le bruit sur la mesure des signaux permet d'espérer une résolution de à 10 pm à 43 ms. Les imperfections optiques du montage ont été mises en évidence: elles ont été décrites par une expression analytique, puis à l’aide d’optiques dédiées réduites au niveau nécessaire pour le fonctionnement de l'instrument. La phase des signaux de battement à 20 GHz est affectée d'erreurs de plusieurs 10-3 cycles qui, si elles ne sont pas corrigées, provoquent des erreurs de la mesure de longueur par une ou plusieurs fois la longueur d'onde optique. Nous avons réalisé une étude spécifique du couplage amplitude-phase à l'origine de cette déformation, et montré qu'il est en partie d'origine thermique, lié à la puissance de plusieurs kW/cm² dissipée dans les photodiodes à 20 GHz. Cet effet, voisin de ce qui est connu depuis quelques années en instrumentation microonde sous le nom d' "effet mémoire", est difficile à prendre en compte et la correction qui est faite sur les données ne parvient pas totalement à éviter que le télémètre délivre des valeurs erronées de la distance. En conclusion de ce mémoire deux options sont présentées afin de remédier à cette déformation du signal et d'aboutir à un instrument de haute exactitude. / Beyond its use in geophysics or in large scale metrology, laser-based measurement of long distances is expected to find numerous applications in space missions. Synthetic aperture instruments in formation flight require that the constellation geometry be known and controlled to much better than the wavelength of the observation window. To meet these needs, we have been studying a novel laser ranging scheme that combine an interferometric measurement, performed on a two-mode laser beam, and a time of flight measurement. My thesis focused on the design, implementation, and characterization of the interferometric measurement. To prevent systematic errors due to slow drifts in the microwave components, the two phase measurements of optical wavelength (1.55 microns) and the synthetic wavelength (15 mm) are extracted from the same two-mode interference signal by using a dedicated measurement procedure: we perform interference signal measurements at three optical frequency values of the laser source, calculated based on the time of flight measurement result. The rangefinder utilizes the two-mode interference signal properties and exploits phase and amplitude of the 20 GHz signal in a manner to eliminate long-term phase drifts of the microwave signal in the measurement chain. We can expect in less than 0.1 s, a measurement with sub-nanometer accuracy and resolution. The experimental setup showed that the principle is correct. On an optical path measurement in air, we obtained a 100 pm resolution in 100 us, which allows us to observe the acoustic noise. The measurement signal noise allows expecting a 10 pm resolution in 43 ms. Optical imperfections in the setup have been observed. They were described by an analytical expression, then, using dedicated optics, they were reduced to the level required for the instrument operation. The phase of two-mode signal is affected to several 10-3 cycle errors which, if not corrected, result in errors in the measurement length by multiples of the optical wavelength. We performed a specific study of amplitude-to-phase coupling causing this deformation, and showed that it is part of thermal origin, related to the power of several kW/cm² dissipated in the 20 GHz photodiodes. This effect, close to what has been known for some years in microwave instrumentation under the name of "memory effects", is difficult to take into account and the correction made on the data can not completely prevent the rangefinder from delivering incorrect values of the distance. In concluding this thesis two options are presented to remedy this signal distortion and result in a high accuracy instrument.

This thesis focuses on the development of a distributed mobile robot localization and communication system for special interventions like those carried out by fire-fighters in fire ground search and rescue. The use case scenario is related to the one described for the GUARDIANS EU project, where a swarm formation of mobile robots accompany a fire fighter during a rescue intervention in a warehouse. In this line, localizing the robots and the fire fighter during an indoor intervention with the presence of smoke is one of the more interesting challenges in this scenario. Several localization techniques have been developed using ultrasonic sensors, radio frequency signals and visual information. It has also been studied several communication protocols that can help to improve the efficiency of the system in such scenario and a proposal for designing a cross-layer communication platform that improves the connectivity of the mobile nodes during an intervention and reduces the number of lost data packets.

This report describes the design and implementation of a prototype for an amplitude modulated laser rangefinder, which is made on a PCB consisting of a laser module emitting light, a photodiode receiving the light reflected from the target, and other components. The design is made for the different power levels, generation of the modulation output and the reception of the signal. The sinusoidal wave is generated with an oscillator circuit and filtered out to produce a pure sine signal. The system requires different voltage levels and current values, which is done with DC-DC converters. Finally, a receiver circuit is implemented to detect the modulation, which needs a device that transfers light energy into voltage. Many tests have been made to optimize the analog circuit for a stable output. The prototype was created as a PCB design with a laser module and a photodiode mounted on it. In the end, satisfactory results were obtained up to the receiving part, however, the prototype was tested with an external circuit for light detection. There is considerable room for improvement, e.g., signal sampling, working receiver and use of standard voltage levels, but this thesis intends to provide a basis for future work.

This work proposes an appearance-based SLAM method whose main contribution is the Feature Stability Histogram (FSH). The FSH is built using a voting schema, if the feature is re-observed, it will be promoted; otherwise it progressively decreases its corresponding FSH value. The FSH is based on the human memory model to deal with changing environments and long-term SLAM. This model introduces concepts of Short-Term memory (STM), which retains information long enough to use it, and Long-Term memory (LTM), which retains information for longer periods of time. If the entries in the STM are rehearsed, they become part of the LTM (i.e. they become more stable). However, this work proposes a different memory model, allowing to any input be part of the STM or LTM considering the input strength. The most stable features are only used for SLAM. This innovative feature management approach is able to cope with changing environments, and long-term SLAM. / Este trabajo propone un método de SLAM basado en apariencia cuya principal contribución es el Histograma de Estabilidad de Características (FSH). El FSH es construido por votación, si una característica es re-observada, ésta será promovida; de lo contrario su valor FSH progresivamente es reducido. El FSH es basado en el modelo de memoria humana para ocuparse de ambientes cambiantes y SLAM a largo término. Este modelo introduce conceptos como memoria a corto plazo (STM) y largo plazo (LTM), las cuales retienen información por cortos y largos periodos de tiempo. Si una entrada a la STM es reforzada, ésta hará parte de la LTM (i.e. es más estable). Sin embargo, este trabajo propone un modelo de memoria diferente, permitiendo a cualquier entrada ser parte de la STM o LTM considerando su intensidad. Las características más estables son solamente usadas en SLAM. Esta innovadora estrategia de manejo de características es capaz de hacer frente a ambientes cambiantes y SLAM de largo término.

Die Kartierung und Lokalisierung eines mobilen Roboters in seiner Umgebung ist eine wichtige Voraussetzung für dessen Autonomie. In dieser Arbeit wird der Einsatz eines 3D-Laserscanners zur Erfüllung dieser Aufgaben untersucht. Durch die optimierte Anordnung eines rotierenden 2D-Laserscanners werden hochauflösende Bereiche vorgegeben. Zudem wird mit Hilfe von ICP die Kartierung und Lokalisierung im Stillstand durchgeführt. Bei der Betrachtung zur Verbesserung der Bewegungsschätzung wird auch eine Möglichkeit zur Lokalisierung während der Bewegung mit 3D-Scans vorgestellt. Die vorgestellten Algorithmen werden durch Experimente mit realer Hardware evaluiert.

Die Kartierung und Lokalisierung eines mobilen Roboters in seiner Umgebung ist eine wichtige Voraussetzung für dessen Autonomie. In dieser Arbeit wird der Einsatz eines 3D-Laserscanners zur Erfüllung dieser Aufgaben untersucht. Durch die optimierte Anordnung eines rotierenden 2D-Laserscanners werden hochauflösende Bereiche vorgegeben. Zudem wird mit Hilfe von ICP die Kartierung und Lokalisierung im Stillstand durchgeführt. Bei der Betrachtung zur Verbesserung der Bewegungsschätzung wird auch eine Möglichkeit zur Lokalisierung während der Bewegung mit 3D-Scans vorgestellt. Die vorgestellten Algorithmen werden durch Experimente mit realer Hardware evaluiert.