A real-time 3-D relative position estimator is presented for fixed-wing UAV swarm system in formation flight, using measurements from IMU, compass, GPS, and a set of UWB ranging radios. Instead of using stationary UWB anchors to provide 3-D coordinate and fusing it with IMU, the estimator uses UWB measurements for the construction of a non-convex function, and calculates the global optimum of the non-convex function to get position estimation, while the GPS positions are used to provide bearing information. Actual flight experiments with seven fixed-wing UAVs are conducted outdoors, and the experimental results indicate that the proposed scheme achieves lower distance estimation error between neighbor UAVs compared to traditional GPS/IMU/UWB fusing algorithm using EKF.

The intermolecular 1,3-diamination reaction of readily available alkenes with N-fluorobis(benzenesulfonamides) catalyzed by rhodium(II) is reported herein. The isomers of the terminal and internal alkenes, even mixtures, all provided the same allylic 1,3-diamine products under mild reaction conditions. The resulting diaminated products can be derived to functionalized diamines and can further generate allylic triamines. Mechanistic studies revealed that the rhodium(II) compounds catalyzed a variety of chemical transformations during the reactions based on their single-electron redox catalytic cycle, specifically radical polarity crossover in terminal alkenes and the direct activation of allylic C−H bonds followed by radical cross-coupling in the internal alkenes. These results show the potential of rhodium(II) in C−H amination reactions in addition to the well-known transformations of rhodium nitrenoids.

Using the single-electron oxidation cycle of a dirhodium catalyst, amination can form two primary C–N bonds in a one-step process.

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