Non-myopic Sensor Path Planning for Emitter Localization with a UAV

This paper addresses the problem of localizing a stationary RF emitter with a mobile UAV, equipped with a single directional antenna. By rotating around its vertical axis, it determines a bearing towards the emitter. Our interest is in optimally selecting the measurement positions to achieve a fast localization. The majority of such systems described in the literature use greedy planning to select the next measurement position. This work experimentally tests an algorithm that performs a non-myopic planning until the final localization step. The algorithm is based on the policy rollout principle and showed good performance in previous simulative studies. It is adapted to match the needs of a real world setup and evaluated in flight trials. Adaptions include the avoidance of close range measurements to prevent inaccurate measurements at high elevation, and the filtering of poor measurements

Raízes de Musa spp. hospedam fungos endofíticos com potencial de controle de Fusarium oxysporum f. sp. cubense.

Aiming to understand the role of root-associated endophytic fungi against Fusarium oxysporum f. sp. cubense (Foc) we screened 25 non-commercial genotypes of Musa spp. from field collections in Brazil and Costa Rica. Analyses of Tefa-1? and/or ITS genome regions of the 150 isolates obtained revealed that most frequent genera were Trichoderma spp. and F. oxysporum. Fungi such as Gloeotinia temulenta and others isolates with no significant similarities to the database analysed are potentially new descriptions. Some genera were more frequent or uniquely found on certain genotypes, but endophyte-host specificity needs to be verified. Antagonism tests against Foc revealed that most Trichoderma isolates are better competitors than Foc in vitro. T. asperellum isolates showed the highest inhibition (> 80%) and parasitism (100%) levels. Some T. asperellum isolates were also able to parasite non-pathogenic F. oxysporum isolates even coming from the same host. Our results revealed that Musa spp. roots are hosts of a high diversity of culturable fungi including potential biocontrol agents against Foc, but also indicate complex in planta interactions among endophytes

A Rollout Based Path Planner for Emitter Localization

This paper explores the problem of localizing an emitter with a mobile sensor platform using noisy bearing measurements. It is assumed, that the measuring procedure requires the platform to be stationary for a certain amount of time. Therefore, there exists a trade-off between using time to take one or more measurements and moving to a more advantageous position for observing a target. Using a rollout based algorithm we optimize the time necessary until a given localization accuracy is reached and compare the performance of this algorithm with several algorithms found in literature