Abstract: The invention discloses a method for synthesizing 1,7-naphthyridine derivatives, which relates to the technical field of synthesizing pharmaceutical intermediates and organic chemical intermediates, wherein the method includes: (1) 2-chloro-3-amino-pyridine being used as Compound I as a starting material, and protecting an amino group to prepare Compound II; (2) the Compound II reacting with an aldehydation reagent under alkaline conditions to obtain Compound III; (3) cyclizing the Compound III with acrylate compounds under the action of Lewis acid to prepare compound IV.

Abstract: A method for constructing a structural semantic map under an underground weak-light and low-texture environment is provided. The method includes: fusing traditional methods with a parameter line detection and verification model of structural semantics of a Transformer; and establishing a geometric primitive half-plane search method guided by the direction of structural information. The method also includes establishing a neighborhood greedy expansion algorithm based on a geometric primitive model; and optimizing geometric primitive poses and boundaries one by one. The method further includes fusing a point cloud map with structural information, and establishing a semantic map with geometric structure primitives.

Abstract: The method includes: obtaining point cloud information collected by a depth camera, laser information collected by a lidar, and motion information of an unmanned aerial vehicle (UAV); generating a raster map based on the laser information, and obtaining pose information of the UAV based on the motion information; obtaining a map model through fusing the point cloud information, the raster map, and the pose information by a Bayesian fusion method; and correcting a latest map model by feature matching based on a previous map model.

Abstract: A ceramic electronic component includes a body including a dielectric layer and an internal electrode; and an external electrode disposed on the body and connected to the internal electrode. The dielectric layer has a perovskite structure represented by a general formula ABO3 as a main phase, and includes a region in which Dy is dissolved. In the region in which Dy is dissolved, an atomic ratio of a content of Dy dissolved in an A-site of the perovskite structure to a content of Dy dissolved in a B-site is 1.6 or more and 2.0 or less.

Abstract: Sized-bridging agents, wellbore fluid compositions including the agents, and methods utilizing said compositions control, reduce, or prevent fluid losses in wellbores and/or formation damages. One or more divalent organic salts disclosed herein are designed to help mitigate fluid loss by temporarily reducing the permeability of the formation around the wellbore. The sized-bridging agents include sized-divalent organic salts for forming one or more filter cakes to seal one or more portions of the wellbores thereby reducing rates of fluid loss and damages to formations.

Abstract: A ceramic electronic component includes a body including a dielectric layer and an internal electrode; and an external electrode disposed on the body and connected to the internal electrode. The dielectric layer has a perovskite structure represented by a general formula ABO3 as a main phase, and includes a region in which Dy is solid solubilized. In the region in which the Dy is solid solubilized, an X-ray count of Dy solid-solubilized in an A-site of the perovskite structure measured by using Scanning Transmission Electron Microscopy-Energy Dispersive X-ray Spectroscopy (STEM-EDS) is AD, an X-ray count of Dy solid-solubilized in a B-site of the perovskite structure is BD, and an average value of AD/BD is 1.6 or more and 2.0 or less.

Abstract: The present application discloses an airborne positioning method and system for an aviation navigation network, and relates to the technical field of satellite navigation. The airborne positioning method for an aviation navigation network is applied to an omnisource navigation system, and comprises the following steps: acquiring the original observation data of the omnisource navigation system; Filtering the original observation data based on dead reckoning to obtain filtered observation data; Unify that filtered observation data in time and space to obtain observation data to be fused; The adaptive fusion algorithm of omnisource navigation based on variance optimization is adopted to fuse the observation data to be fused to obtain the fused data; the fused data is used to characterize the position of the target aircraft at the current moment. The present application can improve the accuracy of the positioning result.

Abstract: The present disclosure provides a multi-view collaborative tracking method and apparatus for a fast moving target under a low luminance condition, including a multi-view target tracking algorithm based on radar-vision fusion data and an unmanned aerial vehicle (UAV) cluster collaborative tracking technology. This method takes the spatiotemporal normalized multi-source data as the learning objective of multi-agent reinforcement learning, to drive the cluster to collect data from multiple angles and directions. In this way, highly-efficient multi-angle collaborative observation can be performed on a high-speed moving object in an environment of weak texture and low luminance.

Abstract: Aspects of the disclosure provide for the use and training of a model configured to provide an estimated time of arrival (ETA) for transporting an object. Data may be received from a reader device. The data may identify a tracking tag and a first timestamp. Based on the received data, a location of the tracking tag at the first timestamp may be determined. A starting location and second timestamp for the tracking tag and a destination location and third timestamp for the tracking tag may be identified. A list including at least one dwell time and dwell location for the tracking tag may be identified. The model may be trained to output the ETA, a dwell time, and a dwell location based on the determined location, the starting location, the destination location, the first timestamp, the second timestamp, the third timestamp, and the list.

Abstract: A method for evaluating quality of a point cloud map based on matching includes the following steps: S1, acquiring the to-be-evaluated point cloud map as a point cloud matching algorithm input; S2, acquiring a point cloud sample set for matching; S3, matching by using a point cloud matching algorithm, and iterating to obtain estimated three-dimensional coordinate system transforms; S4, calculating point cloud matching errors; and S5, taking an obtained quality evaluation score of the to-be-evaluated point cloud map as a point cloud matching algorithm output. The method for evaluating the quality of the point cloud map based on matching can evaluate the quality of the point cloud map in a full-automatic manner without the dependence on truth values and artificial calibration, so as to improve the quality evaluation efficiency of the point cloud map.

Abstract: An ARAIM availability prediction method under a complex terrain environment is provided. The method includes: 1) selecting positioning points according to an air line; 2) calculating terrain shielding angles; 3) predicting visible satellites; 4) determining a fault mode that needs to be monitored; 5) calculating a positioning error variance, an influence coefficient of a nominal deviation, and a variance of a solution separation test statistic; and 6) calculating a threshold of a solution separation test, calculating a protection level, and determining availability. According to the method, the terrain shielding angles are calculated based on terrain model data, and the visible satellites are predicted based on ephemeris data or almanac data to further calculate a protection level, while determining the availability; and the accuracy of availability prediction can, by considering the effect of terrain barriers on the prediction of the visible satellites, be improved to ensure the safety of aircrafts.

Abstract: The present disclosure relates to a technical field for airborne navigation and discloses a data acquisition system and method for airborne navigation devices based on unmanned aerial vehicle. The system includes an unmanned aerial vehicle flight control system, a navigation devices test antenna array, a multi-channel signal processing module, a signal acquisition module, an ADS-B transmitting module, a GNSS receiver, a UHF data link receiver, a power module and a ground station. The unmanned aerial vehicle is equipped with corresponding modules to receive signals from ground navigation devices, perform corresponding processing and storage, and transmit data to the ground, at the same time, receive control instructions sent by the ground to complete corresponding monitoring, analysis and inspection.

Abstract: A system and a method are provided for feasibility evaluation of UAV Digital Twin based on Vicon motion capture system is disclosed, which establishes a mission feasibility evaluation model according to flight history data of a target UAV acquired by the UAV Digital Twin system. The mission feasibility evaluation model includes a UAV trajectory prediction module and a mission feasibility determination module. The UAV trajectory prediction module acquires real-time position and attitude information of the target UAV according to the Vicon motion capture system, and predicts target flight trajectory of the target UAV according to the real-time position and attitude information. The mission feasibility determination module compares the position difference between an end point of the target flight trajectory and preset designated mission point to evaluate feasibility of target mission of the target UAV.

Abstract: A beamforming method, a network device, a terminal, and a storage medium are disclosed. The beamforming method may include: acquiring Direction of Arrival (DOA) information; obtaining a first beamforming weight in a first polarized antenna direction according to the DOA information; acquiring precoding matrix indicator information; acquiring a phase difference between the first polarized antenna direction and a second polarized antenna direction according to the precoding matrix indicator information; obtaining a second beamforming weight in the second polarized antenna direction according to the first beamforming weight and the phase difference; and producing a formed beam according to the first beamforming weight and the second beamforming weight.

Abstract: The present invention discloses a APNT service positioning and integrity monitoring method and system. The method includes the following steps: determining a positioning accuracy requirement in a target scene; when the positioning accuracy requirement is high-accuracy positioning, determining a position of an aircraft by adopting a combined positioning algorithm, and monitoring the integrity of a combined positioning by adopting a multi-solution separation mode; when the positioning accuracy requirement is low-accuracy positioning, judging whether the aircraft is a high-altitude user; if not, adopting an air-to-air positioning algorithm for a high-altitude user and a low-altitude user based on LDACS to determine the position of the aircraft, and adopting a least square residual method to monitor the integrity of the air-to-air positioning.

Abstract: A constellation configuration optimization method of a low earth orbit (LEO) satellite augmentation system for an ARAIM application includes: 1, traversing vertical protection levels after all subset solutions and fault modes under the condition that integrity risk and continuity risk are equally distributed, and determining the constraint conditions of LEO satellite constellation configuration parameters; 2, determining objective functions of LEO satellite constellation configuration parameters x1, x2, x3, x4, eliminating calculated values of abnormal vertical protection levels, and screening initial populations of the parameters x1, x2, x3, x4; 3, calculating fitness of the objective functions; 4, starting from a second generation population, merging a parent population with an offspring population to form a new offspring population; 5, performing local optimal selection on the new offspring population, screening out a maximum value of the objective functions as an optimal offspring, and repeating step 4 un

Abstract: Complicated system fault diagnosis method and system based on a multi-stage model are provided. The method includes: establishing an integer-order mathematical model, a 0.1-level fractional order mathematical model, and a 0.01-level fractional order mathematical model of a permanent magnet synchronous motor system; designing an integer-order status observer based on the integer-order mathematical model, designing a 0.1-level fractional order status observer based on the 0.1-level fractional order mathematical model, and designing a 0.01-level fractional order status observer based on the 0.01-level fractional mathematical model; corresponding residual values can be obtained by the observers and compared with corresponding threshold values to judge whether there is a fault. The system includes first through third modules. Observers with different accuracy degrees are set up and the permanent magnet synchronous motor system is diagnosed through the observers.