The response of thermosphere density to geomagnetic storms is a complicated physical process.Multi-satellite joint observations at the same altitude but different local times(LTs)are important for understanding this p...The response of thermosphere density to geomagnetic storms is a complicated physical process.Multi-satellite joint observations at the same altitude but different local times(LTs)are important for understanding this process;however,until now such studies have hardly been done.In this report,we analyze in detail the thermosphere mass density response at 510 km during the April 23−24,2023 geomagnetic storm using data derived from the TM-1(TianMu-1)satellite constellation and Swarm-B satellites.The observations show that there were significant LT differences in the hemispheric asymmetry of the thermosphere mass density during the geomagnetic storm.Densities observed by satellite TM02 at nearly 11.3 and 23.3 LTs were larger in the northern hemisphere than in the southern.The TM04 dayside density observations appear to be almost symmetrical with respect to the equator,though southern hemisphere densities on the nightside were higher.Swarm-B data exhibit near-symmetry between the hemispheres.In addition,the mass density ratio results show that TM04 nightside observations,TM02 data,and Swarm-B data all clearly show stronger effects in the southern hemisphere,except for TM04 on the dayside,which suggest hemispheric near-symmetry.The South-North density enhancement differences in TM02 and TM04 on dayside can reach 130%,and Swarm-B data even achieve 180%difference.From the observations of all three satellites,large-scale traveling atmospheric disturbances(TADs)first appear at high latitudes and propagate to low latitudes,thereby disturbing the atmosphere above the equator and even into the opposite hemisphere.NRLMSISE00 model simulations were also performed on this geomagnetic storm.TADs are absent in the NRLMSISE00 simulations.The satellite data suggest that NRLMSISE00 significantly underestimates the magnitude of the density response of the thermosphere during geomagnetic storms,especially at high latitudes in both hemispheres.Therefore,use of the density simulation of NRLMSISE00 may lead to large errors in satellite drag calculations and orbit predictions.We suggest that the high temporal and spatial resolution of direct density observations by the TM-1 constellation satellites can provide an autonomous and reliable basis for correction and improvement of atmospheric models.展开更多
针对无人机在复杂环境下的三维路径规划问题,集成传统的粒子群优化(particle swarm optimization,PSO)算法和灰狼优化(grey wolf optimization,GWO)算法,提出了一种PSO-GWO复合算法。首先,采用了非线性控制参数和加权自适应的个体位置...针对无人机在复杂环境下的三维路径规划问题,集成传统的粒子群优化(particle swarm optimization,PSO)算法和灰狼优化(grey wolf optimization,GWO)算法,提出了一种PSO-GWO复合算法。首先,采用了非线性控制参数和加权自适应的个体位置更新策略来平衡算法的全局搜索能力和局部搜索能力;然后,使用随机指导策略来增加解的多样性;最后,使用B样条曲线平滑所生成的飞行路径,使路径更适用于无人机。实验结果表明,PSO-GWO复合算法可以生成一条安全可行的路径,其性能明显优于GWO算法和其他改进GWO算法。展开更多
基金funded by the China Manned Space Program (Grant Y59003AC40)TM-1 Constellation Atmospheric Density Detector (Grant E3C1162110)
文摘The response of thermosphere density to geomagnetic storms is a complicated physical process.Multi-satellite joint observations at the same altitude but different local times(LTs)are important for understanding this process;however,until now such studies have hardly been done.In this report,we analyze in detail the thermosphere mass density response at 510 km during the April 23−24,2023 geomagnetic storm using data derived from the TM-1(TianMu-1)satellite constellation and Swarm-B satellites.The observations show that there were significant LT differences in the hemispheric asymmetry of the thermosphere mass density during the geomagnetic storm.Densities observed by satellite TM02 at nearly 11.3 and 23.3 LTs were larger in the northern hemisphere than in the southern.The TM04 dayside density observations appear to be almost symmetrical with respect to the equator,though southern hemisphere densities on the nightside were higher.Swarm-B data exhibit near-symmetry between the hemispheres.In addition,the mass density ratio results show that TM04 nightside observations,TM02 data,and Swarm-B data all clearly show stronger effects in the southern hemisphere,except for TM04 on the dayside,which suggest hemispheric near-symmetry.The South-North density enhancement differences in TM02 and TM04 on dayside can reach 130%,and Swarm-B data even achieve 180%difference.From the observations of all three satellites,large-scale traveling atmospheric disturbances(TADs)first appear at high latitudes and propagate to low latitudes,thereby disturbing the atmosphere above the equator and even into the opposite hemisphere.NRLMSISE00 model simulations were also performed on this geomagnetic storm.TADs are absent in the NRLMSISE00 simulations.The satellite data suggest that NRLMSISE00 significantly underestimates the magnitude of the density response of the thermosphere during geomagnetic storms,especially at high latitudes in both hemispheres.Therefore,use of the density simulation of NRLMSISE00 may lead to large errors in satellite drag calculations and orbit predictions.We suggest that the high temporal and spatial resolution of direct density observations by the TM-1 constellation satellites can provide an autonomous and reliable basis for correction and improvement of atmospheric models.
文摘针对无人机在复杂环境下的三维路径规划问题,集成传统的粒子群优化(particle swarm optimization,PSO)算法和灰狼优化(grey wolf optimization,GWO)算法,提出了一种PSO-GWO复合算法。首先,采用了非线性控制参数和加权自适应的个体位置更新策略来平衡算法的全局搜索能力和局部搜索能力;然后,使用随机指导策略来增加解的多样性;最后,使用B样条曲线平滑所生成的飞行路径,使路径更适用于无人机。实验结果表明,PSO-GWO复合算法可以生成一条安全可行的路径,其性能明显优于GWO算法和其他改进GWO算法。
