This paper develops a distributed method, namely, allocation with time windows (DATW) for managing the multi-UAV task assignment problem (MTAP) complex window constraints. By aiming directly to minimize average completion time, pro-posed DATW intends achieve conflict-free result that allocates all tasks within validity windows. Based on decentralized PI (Performance Impact) framework, proposed algorithm addresses MTAP in three-phase strategy, which includes inclusion, conflict resolution,...

With the rapid development of satellite technology and need to satisfy increasing demand for location-based services, in challenging environments such as indoors, forests, canyons, there is an urgent improve position accuracy these environments. However, traditional algorithms obtain solution through time redundancy exchange spatial redundancy, they require continuous observations that cannot real-time location services. In addition, must also consider clock bias between receiver. Therefore,...

Abstract Objective The paper aims to present a generalized modulation scheme that can improve the anti-interference performance of global navigation satellite systems (GNSS) and mitigate ambiguity problem in BOC modulation. Summary background data With exponential growth location-based services, there is need positioning accuracy capability resist against external interference challenging environments, such as urban canyons, forested terrains, indoor areas, which signal attenuation,...

Challenging environments such as cities, canyons, and forests have become key factors affecting navigation stability. When users pass through intricate overpasses winding road sections, due to the fluctuation of geoid, there will be a large problem in elevation measurement error user’s receiver. In addition, even if low Earth orbit (LEO) constellation has thousands satellites, no technical problems regard destroying LEO satellites with existing technology extreme situations warfare...

Objective Glucose 6-phosphate dehydrogenase (G6PD) deficiency increases the risk of neonatal hyperbilirubinemia. The aim this study is to evaluate factors associated with hyperbilirubinemia in infants from western part Guangdong Province, and assess contribution G6PD jaundice. Methods term People's Hospital Yangjiang June 2018 July 2022 were recruited for retrospective analysis. All underwent quantitative detection enzyme. etiology was determined through laboratory tests clinical...

The global navigation satellite system (GNSS) is a critical infrastructure for positioning, navigation, and timing. Recently, vigorous implementation of low earth orbit (LEO) communication satellites has provided new opportunity developing GNSS. However, most the existing modulations are only applicable narrow bandwidths; hence, broadband modulation with good compatibility scalability needed. This paper presents multicarrier modulation, namely orthogonal frequency division multiplexing...

To improve the anti-interference performance and mitigate autocorrelation function (ACF) ambiguity of dual-frequency multiplexing modulation, we propose a new type modulation: frequency-hopping alternated binary offset carrier (FH-AltBOC) modulation based on technique. The is generalized includes AltBOC so it inherits advantages while also exhibiting properties, such as low ambiguity, probability intercept, better anti-narrowband interference multipath performance. We first establish...

To solve the problem of location service interruption that is easily caused by incomplete visual satellite environments such as occlusion, urban blocks and mountains, we propose an altimeter + inertial navigation system (INS) giant low earth orbit (LEO) dual-satellite (LEO2) switching integrated algorithm based on a similar ellipsoid model unscented Kalman filter (UKF). In addition to effectively improving INS error, for LEO without assistance, our can also significantly suppress excessive...

To solve the problem of location services in harsh environments, we propose an integrated navigation algorithm based on broadband low-earth-orbit (LEO) satellite communication and integration with 3-satellite alternate switch ranging. First, describe principle processing flow detail; next, analyze model ranging error source a combined multipath non-line-of-sight (NLOS) analysis model, which avoids discussing complex number paths its modeling process; addition, also multimodal Gaussian...

The prevalence of G6PD deficiency has not been reported in Yangjiang, a western city Guangdong province. This study aims to investigate the molecular characteristics this region.

Satellite edge computing (SEC) is an important component for future network deployments. This paper studies the task offloading in SEC system with limited buffers (SEC-LB) and data dependencies among tasks. Due to competition buffers, a resource circular-waiting pattern may be formed, leading deadlock. To well analyze deadlocks, Petri net model of SEC-LB constructed first time. Then, net-based modified Banker's algorithm (MBA) proposed determine safety state, deadlock avoidance policy (DAP)...

Satellite edge computing (SEC) plays an increasing role in earth observation, due to its global coverage and low-latency service. In SEC, it is pivotal offload diverse observation-data-processing tasks the appropriate satellites. Nevertheless, sparse intersatellite link (ISL) connections, hard gather complete information from all Moreover, dynamic arriving will also influence obtained offloading assignment. Therefore, one daunting challenge SEC achieving optimal assignments with...

This study focuses on a constrained consensus problem of heterogeneous linear multi-agent systems with nonconvex input constraints and switching graphs. A distributed control algorithm the time-varying gain is presented to ensure each agent stay in set make all agents reach common point. Through method nonnegative matrices, we obtain sufficient conditions for system. It shown that can as long union communication graphs contains spanning trees. Finally, simulations are provided show...

For satellite or aircraft networks, tracking, telemetry, and control (TT&C) data transmission between different nodes are necessary. Traditional measurement mostly adopts the frequency division duplex (FDD) mode uses a continuous system to achieve high-precision measurement. However, as number of network increases, suffers from complex domain allocation, high-cost equipment is required. This paper proposes integrated signal in time (TDD) improve utilization address these circumstances....

The objective of this study was to analyze the clinical characteristics pregnant women infected with COVID-19 omicron variant and their neonates during outbreak in Guangdong province, China.The data were retrospectively collected from two hospitals province. Information recorded included age mother, date birth, sex, weight at mode delivery, gestational age, feeding mode, Apgar score, signs, medical records, underlying comorbidities laboratory results. presence SARS-CoV-2 viral RNA tested...

The paper considers the ant colony optimization (ACO) methodology for designing an active debris removal mission. goal is to optimize a sequence of transfers using orbital transfer vehicle rendezvous with multiple pieces purpose removal. consists two phases: first phase obtains optimal sequence, and second related trajectory optimization. During planning process, refined approximation proposed estimate times necessary costs individual transfers. problem can then be mapped into variant...

In this article, a constrained consensus problem for heterogeneous multi-agent system with nonconvex input constraints and nonuniform time delays was considered. The is composed of hybrid agents including first-order to σth-order agents, where σ positive bounded integer. It assumed that each agent's control stay in set the communication topology switches among some digraphs. A new distributed algorithm proposed first. And then sufficient conditions are obtained ensure can be reached system....

In challenging environments such as forests, valleys and higher latitude areas, there are usually fewer than four visible satellites. For cases with only two satellites, we propose a dual-satellite alternate switching ranging integrated navigation algorithm based on the broadband low earth orbit (LEO) constellation, which integrates communication (ICN) technology. It is different from traditional algorithm: difference that it can complete precise real-time positioning without an altimeter...

In order to solve the collaborative navigation problems in challenging environments such as insufficient visible satellites, obstacle reflections and multipath errors, improve accuracy, usability, stability of positioning, we propose a dual-way asynchronous precision communication-timing-measurement system (DWAPC-TSM) LEO constellation multi-aircraft cooperative positioning algorithm which gives principle, structure, error analysis DWAPC-TSM system. addition, also analyze effect vehicle...

Frequency-hopping binary offset carrier modulation improves the anti-interference performance and mitigates autocorrelation function (ACF) ambiguity problem of modulation. To save payload resources make high-power amplifiers on satellites operate at nonlinear saturation region, there is further demand for finding an efficient constant-envelope frequency-hopping multiplexing technique to combine several signal components. Thus, we propose a dual-sideband modulation, named asymmetric...