A Scalable Distributed Control Algorithm for Bearing-Only Passive UAV Formation Maintenance.

Unmanned Aerial Vehicles (UAVs) can cooperate through formations to perform tasks. Wireless communication allows UAVs to exchange information, but for the situations requiring high security, electromagnetic silence is needed to avoid potential threats. The passive UAV formation maintenance strategies can fulfill the requirement of electromagnetic silence at the cost of heavy real-time computing and precise locations of UAVs. To pursue high real-time performance without the localization of UAVs, this paper proposes a scalable distributed control algorithm for bearing-only passive UAV formation maintenance. By minimizing necessary communication, pure angle information is applied to maintain UAV formations through distributed control, without the knowledge of the UAVs' precise locations. The convergency of the proposed algorithm is proven strictly and the converging radius is derived. Through simulation, the proposed algorithm is proven to be suitable for a general case and demonstrates fast convergence speed, strong anti-interference capability, and high scalability.

Dual concave grating anastigmatic spectrometer with high spectral resolution for remote sensing.

A dual concave grating imaging spectrometer with anastigmatic imaging has been presented for remote sensing. The optimal arrangements of the gratings and the addition of a cylindrical lens have been determined based on different aberrations and the major corresponding parameter analysis. The advanced Wadsworth mounting can eliminate coma and astigmatism and realize high spectral resolution with low ruling density gratings. The design presents excellent optical performance: the spectral resolution is 0.6 nm, and spatial resolution is 1 mrad/pixel over the waveband of 400 nm centered at 600 nm with NA 0.1. The manufacture and testing of the prototype prove the principle of design and the engineering practicality.

Stigmatic broadband imaging spectrometer with a high numerical aperture.

An advanced Dyson spectrometer has been presented for broadband stigmatic imaging. The spectrometer, with large enough axial spaces and lateral separation among the slit, the imaging plane, and the hemispherical lens, is composed of a thin hemispherical lens and two spherical lenses in the same material, and a reflection concave grating. The new spectrometer design maintains excellent optical performances and decreases inherent stray light of the concentric spectrometer with a high numerical aperture, which owns better engineering applicability.