A study on dual quaternion based cooperative relative navigation of multiple UAVs with monocular vision-inertial integration

This paper addresses a cooperative relative navigation problem for multiple aerial agents,relying on visual tracking information between vehicles.The research aims to investigate a sensor fusion architecture and algorithm that leverages partially available absolute navigation knowledge while exploiting collaborative visual interaction between vehicles in mission flight areas,where satellite navigation-denied regions are irregularly located.To achieve this,the paper introduces a new approach to defining the relative poses of cameras and develops a corresponding process to secure the relative pose information.This contrasts with previous research,which simply linearized the relative pose information of aircraft cameras into navigation states defined in an absolute coordinate system.Specifically,the target pose in relative navigation is defined,and the pose of the camera and feature points are directly derived using dual quaternion representation,which compactly represents both translation and rotation.Furthermore,a mathematical model for the relative pose of the camera is derived through the dual quaternion framework,enabling an explicit pose formulation of relative navigation.The study investigates navigation performance in typical mission flight scenarios using an in-house high-fidelity simulator and quantitatively highlights the contributions of the proposed scheme by comparing the navigation error performance.Consequently,the proposed method demonstrates to have navigation accuracy in decimeter level even in GNSS-denied environments and an improved 3D Root Mean Square(RMS)error by30%smaller than the conventional absolute navigation framework.

Utilizing 3,4-ethylenedioxythiophene(EDOT)-bridged non-fullerene acceptors for efficient organic solar cells

A rational design of efficient low-band-gap non-fullerene acceptors(NFAs)for high-performance organic solar cells(OSCs)remains challenging;the main constraint being the decrease in the energy level of the lowest unoccupied molecular orbitals(LUMOs)as the bandgap of A-D-A-type NFAs decrease.Therefore,the short current density(J_(sc))and open-circuit voltage(V_(oc))result in a trade-off relationship,making it difficult to obtain efficient OSCs.Herein,three NFAs(IFL-ED-4 F,IDT-ED-4 F,and IDTT-ED-2 F)were synthesized to address the above-mentioned issue by introducing 3,4-ethylenedioxythiophene(EDOT)as aπ-bridge.These NFAs exhibit relatively low bandgaps(1.67,1.42,and 1.49 eV,respectively)and upshifted LUMO levels(-3.88,-3.84,and-3.81 eV,respectively)compared with most reported low-band-gap NFAs.Consequently,the photovoltaic devices based on IDT-ED-4 F blended with a PBDB-T donor polymer showed the best power conversion efficiency(PCE)of 10.4%with a high J_(sc) of 22.1 mA cm^(-2) and Voc of 0.884 V among the examined NFAs.In contrast,IDTT-ED-4 F,which was designed with an asymmetric structure of the D-p-A type,showed the lowest efficiency of 1.5%owing to the poor morphology and charge transport properties of the binary blend.However,when this was introduced as the third component of the PM6:BTP-BO-4 Cl,complementary absorption and cascade energy-level alignment between the two substances could be achieved.Surprisingly,the IDTT-ED-4 F-based ternary blend device not only improved the Jscand Voc,but also achieved a PCE of 15.2%,which is approximately 5.3%higher than that of the reference device with a minimized energy loss of 0.488 eV.In addition,the universality of IDTT-ED-2 F as a third component was effectively demonstrated in other photoactive systems,specifically,PM6:BTPe C9 and PTB7-Th:IEICO-4 F.This work facilitates a better understanding of the structure–property relationship for utilizing efficient EDOT-bridged NFAs in high-performance OSC applications.