<p>The purpose of this master thesis, performed at FOI, was to evaluate a range gated underwater camera, for the application identification of bottom objects. The master thesis was supported by FMV within the framework of “arbetsorder Systemstöd minjakt (Jan Andersson, KC Vapen)”. The central part has been field trials, which have been performed in both turbid and clear water. Conclusions about the performance of the camera system have been done, based on resolution and contrast measurements during the field trials. Laboratory testing has also been done to measure system specific parameters, such as the effective gate profile and camera gate distances.</p><p>The field trials shows that images can be acquired at significantly longer distances with the tested gated camera, compared to a conventional video camera. The distance where the target can be detected is increased by a factor of 2. For images suitable for mine identification, the increase is about 1.3. However, studies of the performance of other range gated systems shows that the increase in range for mine identification can be about 1.6. Gated viewing has also been compared to other technical solutions for underwater imaging.</p>

The purpose of this master thesis, performed at FOI, was to evaluate a range gated underwater camera, for the application identification of bottom objects. The master thesis was supported by FMV within the framework of “arbetsorder Systemstöd minjakt (Jan Andersson, KC Vapen)”. The central part has been field trials, which have been performed in both turbid and clear water. Conclusions about the performance of the camera system have been done, based on resolution and contrast measurements during the field trials. Laboratory testing has also been done to measure system specific parameters, such as the effective gate profile and camera gate distances. The field trials shows that images can be acquired at significantly longer distances with the tested gated camera, compared to a conventional video camera. The distance where the target can be detected is increased by a factor of 2. For images suitable for mine identification, the increase is about 1.3. However, studies of the performance of other range gated systems shows that the increase in range for mine identification can be about 1.6. Gated viewing has also been compared to other technical solutions for underwater imaging.

Les politiques urbaines de « reconstruction » post-apartheid de ces dernières décennies n’ont pas permis de réduire les injustices spatiales du Gauteng et de Johannesburg en particulier. Sous l’impulsion des acteurs privés, les résidences fermées d’entrée de gamme, symbole de l’ascension sociale des classes moyennes, diffusent de nouvelles formes de relégation et de fragmentation qui questionnent fortement le lien social, l’étalement et la mobilité croissante. Le peu d’investigations menées sur cette ville « moyenne », qui se veut synonyme de progrès et de modernité, offre l’opportunité de mobiliser une réflexion nouvelle sur les interrelations qui existent entre production de la ville, pratiques et territoires. Loin d’être monolithique, le logement d’entrée de gamme s’est développé à travers maints arrangements institutionnels particuliers et géographiquement situés. Le rôle des acteurs privés impliqués dans la gouvernance urbaine, souvent méconnu et rarement étudié, est devenu la clé de voûte des transformations contemporaines de la ville. L’originalité de ce travail a été de révéler les principes de constitution de savoirs spécialisés et spatialisés, qui éclairent le processus de codification des pratiques et donc la naissance de l’urbanisme sécuritaire institutionnalisé au sein de la métropole.Le détour comparatif avec Delhi a été l’occasion de valider que ces résultats avaient une portée générale cumulable, tout en délocalisant le regard. / The post-apartheid urban policies of the last decades aiming at “rebuilding” the nation, have not led to reducing spatial injustice in Gauteng, and Johannesburg in particular. Spurred on by private actors, bottom-of-the-range closed residences, which symbolise the upward social mobility of the middle class, spread new forms of relegation and fragmentation, thereby challenging social links, urban sprawl and growing mobility. The little research carried out on this “average” city, which is meant to be synonymous with progress and modernity, is an opportunity to develop new thoughts on existing interrelations between urban production, practices and territories.Far from being monolithic, bottom-of-the-range housing is being developed through many specific and geographically located institutional arrangements. The role played by private actors involved in urban governance, which is often largely unknown and rarely being studied, has become the keystone of the city’s contemporary transformations. The novelty behind this research work is that it reveals the principles of what constitutes specialised and spatialized expertise, thereby shedding light on the codification process of practices and, as such, the birth of institutionalised security town planning within the metropolis.Comparing Johannesburg with Delhi was an opportunity to validate the fact that these results could be significantly drawn concurrently, while studying two different sites

Advances in digital signal processing (DSP) and computing technology have resulted in the emergence of increasingly adaptive radar systems. It is clear that the Electronic Attack (EA), or jamming, of such radar systems is expected to become a more difficult task. The reason for this research was to address the issue of jamming adaptive radar systems. This required consideration of adaptive jamming systems and the development of a methodology for outlining the features of such a system is proposed as the key contribution of this thesis. For the first time, game-based optimization methods have been applied to a maritime counter-surveillance/counter-targeting scenario involving conventional, as well as so-called ‘smart’ noise jamming.Conventional noise jamming methods feature prominently in the origins of radar electronic warfare, and are still widely implemented. They have been well studied, and are important for comparisons with coherent jamming techniques.Moreover, noise jamming is more readily applied with limited information support and is therefore germane to the problem of jamming adaptive radars; during theearly stages when the jammer tries to learn about the radar’s parameters and its own optimal actions.A radar and a jammer were considered as informed opponents ‘playing’ in a non-cooperative two-player, zero-sum game. The effects of jamming on the target detection performance of a radar using Constant False Alarm Rate (CFAR)processing were analyzed using a game theoretic approach for three cases: (1) Ungated Range Noise (URN), (2) Range-Gated Noise (RGN) and (3) False-Target (FT) jamming.Assuming a Swerling type II target in the presence of Rayleigh-distributed clutter, utility functions were described for Cell-Averaging (CA) and Order Statistic (OS) CFAR processors and the three cases of jamming. The analyses included optimizations of these utility functions, subject to certain constraints, with respectto control variables (strategies) in the jammer, such as jammer power and spatial extent of jamming, and control variables in the radar, such as threshold parameter and reference window size. The utility functions were evaluated over the players’ strategy sets and the resulting matrix-form games were solved for the optimal or ‘best response’ strategies of both the jammer and the radar.

Advances in digital signal processing (DSP) and computing technology have resulted in the emergence of increasingly adaptive radar systems. It is clear that the Electronic Attack (EA), or jamming, of such radar systems is expected to become a more difficult task. The reason for this research was to address the issue of jamming adaptive radar systems. This required consideration of adaptive jamming systems and the development of a methodology for outlining the features of such a system is proposed as the key contribution of this thesis. For the first time, game-based optimization methods have been applied to a maritime counter-surveillance/counter-targeting scenario involving conventional, as well as so-called ‘smart’ noise jamming.Conventional noise jamming methods feature prominently in the origins of radar electronic warfare, and are still widely implemented. They have been well studied, and are important for comparisons with coherent jamming techniques.Moreover, noise jamming is more readily applied with limited information support and is therefore germane to the problem of jamming adaptive radars; during theearly stages when the jammer tries to learn about the radar’s parameters and its own optimal actions.A radar and a jammer were considered as informed opponents ‘playing’ in a non-cooperative two-player, zero-sum game. The effects of jamming on the target detection performance of a radar using Constant False Alarm Rate (CFAR)processing were analyzed using a game theoretic approach for three cases: (1) Ungated Range Noise (URN), (2) Range-Gated Noise (RGN) and (3) False-Target (FT) jamming.Assuming a Swerling type II target in the presence of Rayleigh-distributed clutter, utility functions were described for Cell-Averaging (CA) and Order Statistic (OS) CFAR processors and the three cases of jamming. The analyses included optimizations of these utility functions, subject to certain constraints, with respectto control variables (strategies) in the jammer, such as jammer power and spatial extent of jamming, and control variables in the radar, such as threshold parameter and reference window size. The utility functions were evaluated over the players’ strategy sets and the resulting matrix-form games were solved for the optimal or ‘best response’ strategies of both the jammer and the radar.