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81.
针对长航时、高精度移动测量系统中加速度计组件标定周期长、参数重复性不好等问题,该文提出一种基于速度误差的加速度计组件闭环标定方法。通过推导加速度计标度因数误差和安装误差的标定误差与系统速度误差之间的关系,以惯性导航系统解算的速度误差作为观测量,设计加速度计组件闭环标定路径,不断对标度因数和安装误差进行修正,并根据加速度计器件精度和标定参数分辨率设定闭环标定结束阈值。标定及导航实验结果表明:加速度计组件闭环标定方法可以完成标度因数和安装误差等9个标定参数的计算,惯导系统定位精度提高20%以上。 相似文献
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全光网(AON，all—optical network)能在光域上实现高速信息流的传输、交换、路由和故障恢复等功能。实现全光网络的关键技术之一是用光交换代替电交换。光交换技术是真正实现全光网关键性功能的必要前提．也是目前国内外光通讯器件厂商研究和开发的热点。这里结合全光网的发展，介绍了一些常用光交换技术的基本原理、性能指标，并对这些常用技术进行了比较，最后对光交换的发展前景做了展望。 相似文献
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基于智能手机的室内定位技术的发展现状和挑战 总被引：2，自引：1，他引：1
室内定位是未来人工智能的核心技术之一,对即将到来的人工智能时代起着举足轻重的作用。开发有效的室内定位新技术是工业界和学术界的研究热点,如谷歌研发的室内视觉定位服务技术、苹果致力推动的基于低功耗蓝牙的iBeacon室内定位技术以及百度携手芬兰IndoorAtlas公司推出的基于磁场匹配的室内定位方案等。然而,受室内复杂环境以及空间布局、拓扑易变等影响,实现准确、可靠、实时的室内定位,满足各类定位需求仍有很大的挑战性。目前,随着智能手机的普及和微机电系统技术的发展,智能手机内置多种传感器和支持丰富的射频信号,可提供不同的定位源。本文从智能手机的内置传感器和射频信号两个方面,综述了现有基于智能手机的室内定位技术,指出各种定位技术的优缺点和应用场景,分析室内定位的发展现状和存在难点,对室内定位技术未来的发展方向进行了展望。 相似文献
84.
《国际泥沙研究》2022,37(6):833-846
Sediment transport has been extensively studied. There is still a need to learn more about the mechanisms that make bed particles move, which is caused by turbulent flow in the low transport stages (above the motion threshold and below continuous transport). This work is focused on the use of an advanced tool to obtain a better perception of sediment transport dynamical methods: an instrumented particle equipped with a micro-electromechanical systems (MEMS) sensor. Particle transport experiments were carried out in a laboratory flume under a variety of well-controlled above-the-threshold-of-motion flow conditions. By using sensor data, the kinetic energies were calculated with different flow rates and particle densities (mimicking different types of sediments sizes) to generate the probability distribution functions (PDFs) of particle transport features, like the total kinetic energy of particles, which provided information about particle interaction with the bed surface during its motion. The energy transfer efficiency was also studied, which can link the rate of energy transferred from the flow to the particle transport, so it can determine how efficiently a flow can transfer energy to the particle and how it affects the magnitude of sediment transport. In general, the instrumented particle response by a series of experiments showed consistent and satisfactory results and demonstrated its capability to record inertial dynamics because of flow turbulence at low cost. These experiments used different particle sizes and densities than those found in real-world sediments because of sensor size and lab limitations. They do, however, provide a framework and trends that others can use to do more research into bed load transport rates in built canals and natural rivers. 相似文献
85.
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86.
The landslide can destroy all kinds of constructions, and seriously hinder people's production and life as well as the development of national economy. Bolt is one of the main methods for slope treatment, but it is difficult to monitor its construction quality and anchoring effect directly. With the rise and development of MEMS (Micro-electro mechanical system) technology, MEMS sensors, with the advantages of small size, low cost and high precision, quickly come out from the conventional monitoring methods and provide new possibilities for the monitoring field in geological engineering. In this paper, based on MEMS sensors, a model test was designed to explore the stability of the slope after treatment by bolts. Natural river sands were used to prepare slopes with angle of 45° through the air-plluviation method. In addition, the tests were divided into two groups (with or without bolts). MEMS sensors were set up in the slope to wirelessly and continually capture the acceleration, angular velocity and angle of slope sliding triggered by simulated rainfall in real-time. It was found that: with no treatment, the acceleration and angle in the interior and the bottom of the slope gradually changed during rainfall, while those parameters in the rear and the surface of the slope had no significant change, which indicated that the slope creep mainly occurred in the interior and the bottom of the slope before failure. When landslides occurred, the movement monitoring indexes in the interior and the bottom of the slope suddenly changed, followed by those in the rear and the surface of the slope, which means that when the sandy slope slides, the interior and the bottom of the slope slides first, and then the rear and the surface of the slope surface fail. This is a typical retrogressive landslide. After the slope was treated by bolts, only creep could be observed during long-term rainfall, and the acceleration and angle in the bottom, interior and surface of the slope gradually changed, while almost no change was found in the rear of the slope, which shows that under rainfall conditions, overall creep occurs for the slope after reinforcement, the slope angle decreases, and there is no landside. The experimental results prove that MEMS sensors can realize low-cost, high-precision, continuous real-time monitoring of slope, and can capture gradual changes of movements before failure and the sudden change when landslide occurs. It should play a certain role in the study of landslide mechanism and landslide warning, and has a broad application in the field of geological engineering monitoring. 相似文献
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