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1.
为满足飞行试验中同场多架飞机训练实时监控的要求,设计一种基于网络电台的遥测传输系统。根据无 线Mesh 网络的结构与特点,采用网状拓扑结构,分析无线Mesh 网络应用于遥测传输的关键技术,对基于网络电台 的遥测传输系统进行设计,并通过飞行试验验证其有效性。试验结果表明:该系统可以实现多架飞机的位置、速度、 航迹等关键数据的实时传输与显示,可靠性高,能够满足飞行试验中对多架飞机近距实时监控与指挥的试飞需求。  相似文献   
2.
Reliability and effectiveness are essential features of satellite transceivers for telemetry and telecommand applications. Modem performance has a strong impact on the success of a satellite mission, in particular, during critical scenarios as the early operation phase, the disposal of a satellite at the end of its life, or the deep‐space missions. In these specific mission critical scenarios, fast and correct data reception is even more important than high channel capacity. An unknown and fast variable channel condition, which can be caused by uncertain spacecraft attitude and large Doppler shift with respect to the data rate, requires efficient and innovative receiver architecture. This paper introduces a complete digital implementation of a transceiver for TM/TC application in low Earth orbit mission that is perfectly compliant with aforementioned requirements. Particular attention is dedicated to the definition and selection of the most appropriate frequency recovery technique; 2 open‐loop techniques that are derived from ML optimal estimator are presented and compared. Additionally, the performance of the proposed receiver is extensively studied and compared with an incoherent technique that is based on the double differential PSK modulation and is known to be suitable for sat‐com in critical scenarios.  相似文献   
3.
CZ-2F运载火箭是中国唯一的载人运载火箭型号,在遥测系统领域具有特别的要求。随着日新月异的科技发展和技术进步,载人火箭对测量的精细化,飞行判定的准确性的需求不断提高。通过分析总结载人运载火箭在遥测系统领域需求特点,结合相关领域的技术发展变化,提出了适合中国载人运载火箭在有限遥测容量下,利用多种路径实现资源利用的最大化,并总结提炼关键技术和发展建议。  相似文献   
4.
The St. Clair-Detroit River System contains a world-class Great Lakes muskellunge (Esox masquinongy) fishery that has avoided the declines observed in many Great Lakes muskellunge populations. Muskellunge are an upper trophic level predator, and therefore a naturally low-density species. Limited fishery-independent data exist on which to base management decisions. To remedy this, we initiated an acoustic telemetry study in May of 2016, in collaboration with the Great Lakes Acoustic Telemetry Observation System. Our objective was to describe patterns of movement of muskellunge in this large and open system to better understand their spatial ecology. We acoustically tagged 133 muskellunge in the Detroit River and Lake St. Clair, and movements of 58 fish that passed our data quality control screens were analyzed. We utilized mixed modelling to assess the effects of sex, length, release location, and season on daily movement rates. We found that movement rates only differed among seasons, with highest movement rates occurring in the fall and lowest movement rates in the winter. Muskellunge tagged at different locations exhibited distinct residency patterns, and fish frequently crossed jurisdictional and waterbody boundaries. Ultimately our study highlights the scope and patterns of muskellunge movement in a large, unimpounded system and demonstrates that management of these fish would benefit from consideration of their full distribution covering multiple management jurisdictions.  相似文献   
5.
Infrequent captures of invasive, non-native grass carp (Ctenopharyngodon idella) have occurred in Lake Erie over the last 30+ years, with recent evidence suggesting wild reproduction in the lake’s western basin (WB) is occurring. Information on grass carp movements in the Laurentian Great Lakes is lacking, but an improved understanding of large-scale movements and potential areas of aggregation will help inform control strategies and risk assessment if grass carp spread to other parts of Lake Erie and other Great Lakes. Twenty-three grass carp captured in Lake Erie’s WB were implanted with acoustic transmitters and released. Movements were monitored with acoustic receivers deployed throughout Lake Erie and elsewhere in the Great Lakes. Grass carp dispersed up to 236 km, with approximately 25% of fish dispersing greater than 100 km from their release location. Mean daily movements ranged from <0.01 to 2.49 km/day, with the highest daily averages occurring in the spring and summer. The Sandusky, Detroit, and Maumee Rivers, and Plum Creek were the most heavily used WB tributaries. Seventeen percent of grass carp moved into Lake Erie’s central or eastern basins, although all fish eventually returned to the WB. One fish emigrated from Lake Erie through the Huron-Erie Corridor and into Lake Huron. Based on our results, past assessments may have underestimated the potential for grass carp to spread in the Great Lakes. We recommend focusing grass carp control efforts on Sandusky River and Plum Creek given their high use by tagged fish, and secondarily on Maumee and Detroit Rivers.  相似文献   
6.
Restoration of a wild-produced lake trout Salvelinus namaycush population in Lake Ontario has not been successful despite the adult population often meeting or exceeding restoration targets. Lack of high-quality spawning habitat in Lake Ontario is suggested as one impediment to recruitment of wild lake trout, although the quantity and location of spawning habitat is poorly understood. If high-quality spawning habitat is limited in Lake Ontario, lake trout may be using uncommon spawning locations such as rivers. Anecdotal angler accounts point to the Niagara River as a lake trout spawning location. To better understand the potential of the Niagara River as a spawning location, egg and juvenile fish collections were conducted 12–14 river kilometers from the mouth of the Niagara River from 2010 to 2012; and mature female lake trout with surgically implanted acoustic tags were monitored from 2015 to 2019. Genetic analyses confirmed 60% of collected eggs and 93% of collected post-hatch juvenile fish in the Niagara River were lake trout. Tagged female lake trout returned to the Niagara River over consecutive years during the spawning season. The short duration of lake trout presence in the river (mean = 56 days/year) suggests female lake trout use the Niagara River primarily for spawning. Diversity in spawning locations may provide lake trout population’s resilience against environmental variability through a portfolio effect. Improved identification of riverine spawning locations, including their overall contribution to wild recruitment, may be a useful tool for managers to restore a wild-produced population of lake trout in Lake Ontario.  相似文献   
7.
Understanding relationships between freshwater fishes and habitat is critical for effective fisheries and habitat management. Habitat suitability indices (HSI) are commonly used to describe fish–habitat associations in rivers and other freshwater ecosystems. When applied to large lakes however, standard sampling procedures are inadequate because of larger sampling areas and an increased risk of fish collection bias through one-time observations. Here, we use lake bathymetry, substrate, and multiple fish telemetry detections collected from a systematically deployed receiver grid to develop HSI for four fish species (lake sturgeon, freshwater drum, common carp, and walleye) in Lake Winnipeg. Seasonal variations in habitat use based on water depth and substrate were observed in three of four species. Lake sturgeon remained in shallow locations with predominantly gravel substrate near the mouth of the Winnipeg River regardless of season. Freshwater drum persisted over fine substrate in both summer and winter but had a broader depth range in the summer compared to winter. Common carp shifted from mid-range depths and silt substrate in the summer to shallow depths and gravel substrate in the winter. Walleye showed an unchanging association to fine substrate but expanded from primarily mid-range depths in the summer to include shallower depths in the winter. These findings show how multiple telemetry detections per fish can be combined with hydroacoustic data to provide informative habitat associations for fishes in a large lacustrine ecosystem.  相似文献   
8.
三维仿真技术在试飞试验领域越来越得到重视与应用。本文介绍了基于三维仿真技术的飞行姿态与航迹监控软件的总体设计结构,并着重阐述了主要组成模块的功能、设计方法与应用效果。该软件的成功研制,使得能够从全局的角度对目标试验机的姿态、位置及系统状态进行掌控。同时,利用回放能够逼真再现飞行全过程,可作为飞行演示和事后分析的一种手段。该软件在提高试飞效率和保障试飞安全方面发挥着重要作用。  相似文献   
9.
本文针对目前无人机系统地面站生产阶段缺少检测设备的问题,提出了地面站综合检测台.在硬件方面,以成熟CPU模块为核心,通过扩展外围接口卡,来满足硬件接口测试需求.在软件方面,采用VC的MFC为基础框架,通过内嵌成熟的仿真模块、实现对地面站各监控软件的功能性检测.经过长期的测试,测试结果表明:本检测台能够对地面站软硬件进行综合性、系统性的检测,是地面站生产阶段不可缺少的设备.  相似文献   
10.
在飞行试验中光电经纬仪主要用于获取飞机及外挂物的运动参数,由于被测目标距离较远或被遮挡时难以快速捕获目标,通常需要利用外引导方式辅助光电经纬仪进行对目标的捕获。飞机上加装GPS接收机后,可实时获取其大地坐标数据,对该数据实时采集并通过 PCM 遥测通道进行编码传输,地面接收该信号能够解调出飞机的实时位置坐标。通过在光电经纬仪上集成遥测PCM接收通道,实时接收机载下传的PCM信息流,提取出飞机的大地坐标数据,经数据处理后转发给光电经纬仪控制系统,驱动光电经纬仪快速捕获目标,从而能够实现对光电经纬仪的外引导。通过对引导数据的分析表明,引导精度能够满足光电经纬仪对目标快速捕获的需求,利用该技术在实际应用中取得了良好效果。  相似文献   
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