全球定位系統(tǒng)的介紹外文翻譯-通信工程-wenkub
2023-05-19 16:13:48 本頁(yè)面
【正文】 d to as multipath. Because it is difficult to pletely correct multipath error, even in high precision GPS units, multipath error is a serious concern to the GPS user. Chapter Seven: Measuring GPS Accuracy As discussed above, there are several external sources which introduce errors into a GPS position. While the errors discussed above always affect accuracy, another major factor in determining positional accuracy is the alignment, or geometry, of the group of satellites (constellation) from which signals are being received. The geometry of the constellation is evaluated for several factors, all of which fall into the category of Dilution Of Precision, or DOP. DOP is an indicator of the quality of the geometry of the satellite constellation. Your puted position can vary depending on which satellites you use for the measurement. Different satellite geometries can magnify or lessen the errors in the error budget described above. A greater angle between the satellites lowers the DOP, and provides a better measurement. A higher DOP indicates poor satellite geometry, and an inferior measurement configuration. Some GPS receivers can analyze the positions of the satellites available, based upon the almanac, and choose those satellites with the best geometry in order to make the DOP as low as possible. Another important GPS receiver feature is to be able to ignore or eliminate GPS readings with DOP values that exceed userdefined limits. Other GPS receivers may have the ability to use all of the satellites in view, thus minimizing the DOP as much as possible. 全球定位系統(tǒng)的介紹 摘自 Corvallis Microtechnology 公司， 1996 第一章 ：什么是 GPS？ 全球定位系統(tǒng)（ＧＰＳ）是一種基于２４顆高度大約１１０００英里的地球軌道衛(wèi)星的定位系統(tǒng)。s investment in GPS is immense. Billions and billions of dollars have been invested in creating this technology for military uses. However, over the past several years, GPS has proven to be a useful tool in nonmilitary mapping applications as well. GPS satellites are orbited high enough to avoid the problems associated with land based systems, yet can provide accurate positioning 24 hours a day, anywhere in the world. Uncorrected positions determined from GPS satellite signals produce accuracies in the range of 50 to 100 meters. When using a technique called differential correction, users can get positions accurate to within 5 meters or less. Today, many industries are leveraging off the DOD39。s massive undertaking. As GPS units are being smaller and less expensive, there are an expanding number of applications for GPS. In transportation applications, GPS assists pilots and drivers in pinpointing their locations and avoiding collisions. Farmers can use GPS to guide equipment and control accurate distribution of fertilizers and other chemicals. Also，GPS is used for providing accurate locations and as a navigation tool for hikers, hunters and boaters. Many would argue that GPS has found its greatest utility in the field of Geographic Information Systems (GIS). With some consideration for error, GPS can provide any point on earth with a unique address (its precise location). A GIS is basically a descriptive database of the earth (or a specific part of the earth). GPS tells you that you are at point X,Y,Z while GIS
畢業(yè)設(shè)計(jì)相關(guān)推薦
鄂ICP備17016276號(hào)-1