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: 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 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 disclosure provides a method and a system for modelling a poor texture tunnel based on a vision-lidar coupling. 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: A method of forming solder paste on an object is provided. The method includes providing a multilayered stencil, each stencil layer having an aperture formed therethrough from a top surface of the respective stencil layer to a bottom surface of the stencil layer. The method also includes applying the stencil to a surface of the object. The method also includes filling a void space formed by a combination of the apertures in the stencil layers with solder paste. The method also includes removing the stencil layers in a sequential manner to leave the solder paste.

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.

Abstract: Tunnel defect detecting method and system using unmanned aerial vehicle (UAV) are provided, and the UAV is equipped with a light-emitting diode (LED) module, a camera, a laser radar, an ultrasonic distance meter and an inertial measurement unit (IMU). The method includes: collecting images in a tunnel based on the LED module and the camera to obtain a training image set; training by using the training image set to obtain a defect detecting model, collecting real-time tunnel images, detecting suspected defects to the real-time tunnel images by the defect detecting model, obtaining pose information of the UAV based on the camera, the laser radar, the ultrasonic distance meter and the IMU to control the UAV to hover. The method can realize accurate pose estimation and defect detection in the tunnel with no GPS signals and highly symmetrical inside.

Abstract: The embodiment of this present disclosure provides a control method of unmanned aerial vehicle (UAV) hovering in tunnel, which comprises the following steps: acquiring hovering information of hovering position of UAV; acquiring the position information of the current position of the UAV; determining flight parameters based on hovering information and position information. The flight parameters are used to control the UAV to move from the current position to the hovering position.

Abstract: An air-cooled diesel generator is provided, and relates to the technical field of diesel generator sets. The air-cooled diesel generator comprises a box body and multiple components provided in the box body, and each component is provided with a separate housing outside; a main air inlet and a main air outlet are formed in the box body, a sub-air inlet and a sub-air outlet are formed in each housing, each sub-air outlet communicates with the main air outlet through an air duct, and each sub-air inlet is provided with an air guide device. Therefore, the air-cooled diesel generator is provided which has better heat dissipation performance.

Abstract: The present disclosure relates to a 2-substituted imidazolidine derivative containing an aryl bipyridyloxy structure, and a preparation method and use thereof, which is obtained by the reaction of 2-substituted imidazolidine and aryl bipyridyloxy compound. The 2-substituted imidazolidine derivative containing an aryl bipyridyloxy structure has a good insecticidal effect on harmful insects, and the compound can be used to prepare insecticides in the fields of agriculture, horticulture, etc.

Abstract: A computer-implemented method includes assigning an auditor weight to each user of a plurality of users. A plurality of audit data is received from the plurality of users, where each audit data is associated with a respective user and includes a set of user ratings for an audit. Final ratings are generated for the audit, with a respective final rating for each item in the audit. Generating the final rating of a first item in the audit includes identifying, in the audit data, user ratings for the first item. The user ratings for the first item include a respective user rating of the first item from each user. Generating the final rating of a first item further includes calculating the final rating of the first item based on a weighted combination of the plurality of user ratings for the first item, according to the respective auditor weight of each user.

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 bidirectional channel control system, method, device, and non-transitory computer-readable storage medium based on Digital Enhanced Cordless Telecommunications is provided. The system comprises a transmitter, at least one receiver, an audio channel, and a text message control channel. The transmitter is configured to send an audio data stream to the at least one receiver through the audio channel. The transmitter is configured to send a control command to the one receiver through the text message control channel in a one-to-one single-point text message mode, and to receive a feedback result from the one receiver in response to the control command.

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 method of forming solder paste on an object is provided. The method includes providing a multilayered stencil, each stencil layer having an aperture formed therethrough from a top surface of the respective stencil layer to a bottom surface of the stencil layer. The method also includes applying the stencil to a surface of the object. The method also includes filling a void space formed by a combination of the apertures in the stencil layers with solder paste. The method also includes removing the stencil layers in a sequential manner to leave the solder paste.

Abstract: A GBAS integrity risk allocation system based on key satellites is used to perform a GBAS integrity risk allocation method, including: reading data from an ephemeris at a certain time, and determining numbers of key satellites, key satellite pairs and key satellite groups at a certain time; under H2 hypothesis, allocating the integrity risks by using the fault probability of satellites in key satellite pairs or key satellite groups, where the integrity risks allocated by using the fault probability of satellites in key satellite pairs or key satellite groups include integrity risks caused by dual-receiver fault and integrity risks caused by ranging source fault; under H0 and H1 hypotheses, allocating the integrity risks by using the fault probability of non-key satellites; making an integrity allocation table according to the integrity risk allocation under the H0, H1 and H2 hypotheses.

Abstract: The present invention provides a BeiDou-based grid augmentation autonomous driving multi-level warning system comprising a Beidou Satellite Ground-based Augmentation system, user terminals and a Vehicles internet system, wherein the Beidou Satellite Ground-based Augmentation system comprises Beidou grid reference stations, a data processing system and a data broadcast system; the user terminal comprises an in-vehicle receiver and a calculating chips. The present invention can reduce the occurrence of traffic accidents and reduce the loss of life and property.

Abstract: A dynamic baseline position domain monitoring system based on satellite navigation and inertial navigation is used to perform a method, including: a) determining a coordinate system and a transformation matrix; b) calculating a theoretical coordinate value of an antenna baseline vector in a earth-centered earth-fixed coordinate system during the movement of a base station carrier; c) determining the number of antenna baseline vectors to be monitored; d) solving the measurement values of the antenna baseline vectors; e) calculating the position domain error of an antenna baseline vector change rate in three directions of x, y and z at epoch k, and normalizing the position domain errors to obtain a normalized value of the position domain errors; f) obtaining the a cumulative sum; g) comparing the cumulative sum with an error monitoring threshold value, and issuing an integrity risk alarm.