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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <title>page_172</title> <link rel="stylesheet" href="reset.css" type="text/css" media="all"> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> </head> <body> <table summary="top nav" border="0" width="100%"> <tr> <td align="left" width="30%" style="background: #EEF3E2"><a style="color: blue; font-size: 120%; font-weight: bold; text-decoration: none; font-family: verdana;" href="page_171.html">< previous page</a></td> <td id="ebook_previous" align="center" width="40%" style="background: #EEF3E2"><strong style="color: #2F4F4F; font-size: 120%;">page_172</strong></td> <td align="right" width="30%" style="background: #EEF3E2"><a style="color: blue; font-size: 120%; font-weight: bold; text-decoration: none; font-family: verdana;" href="page_173.html">next page ></a></td> </tr> <tr> <td id="ebook_page" align="left" colspan="3" style="background: #ffffff; padding: 20px;"> <table border="0" width="100%" cellpadding="0"><tr><td align="center"> <table border="0" cellpadding="2" cellspacing="0" width="100%"><tr><td align="left"></td> <td align="right"></td> </tr></table></td></tr><tr><td align="left"><p></p><table border="0" cellspacing="0" cellpadding="0" width="100%"><tr><td align="right"><font face="Times New Roman, Times, Serif" size="2" color="#FF0000">Page 172</font></td></tr></table><table border="0" cellspacing="0" cellpadding="0" width="100%"><tr><td rowspan="5"></td> <td colspan="3" height="12"></td> <td rowspan="5"></td></tr><tr><td colspan="3"></td></tr><tr><td></td> <td align="center"><font face="Times New Roman, Times, Serif" size="3"><img src="a9212f54646ca9de5655804d8b0e7d04.gif" border="0" alt="0172-01.GIF" width="434" height="217" /></font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table><table border="0" cellspacing="0" cellpadding="0" width="100%"><tr><td rowspan="5"></td> <td colspan="3" height="12"></td> <td rowspan="5"></td></tr><tr><td colspan="3"></td></tr><tr><td></td> <td align="center"><font face="Times New Roman, Times, Serif" size="2">Figure聽5.6<br />GPS聽case<br />(source:聽Ref.聽60).</font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table><table border="0" cellspacing="0" cellpadding="0"><tr><td rowspan="5"></td> <td colspan="3" height="12"></td> <td rowspan="5"></td></tr><tr><td colspan="3"></td></tr><tr><td></td> <td><font face="Times New Roman, Times, Serif" size="3">The latter receiver will be referred to as the <i>rover</i>. A typical DGPS setup is illustrated in Fig. 5.6. Although the discussion is phrased in terms of one base and one rover, the number of roving receivers is not limited. If the position (<i>x</i></font><font face="Times New Roman, Times, Serif" size="1"><sub>0</sub></font><font face="Times New Roman, Times, Serif" size="3"><i>, y</i></font><font face="Times New Roman, Times, Serif" size="1"><sub>0</sub></font><font face="Times New Roman, Times, Serif" size="3"><i>, z</i></font><font face="Times New Roman, Times, Serif" size="1"><sub>0</sub></font><font face="Times New Roman, Times, Serif" size="3">) is not fixed and known, similar techniques can be used to determine the vector [(<i>x</i></font><i><font face="Times New Roman, Times, Serif" size="1"><sub>o</sub></font><font face="Times New Roman, Times, Serif" size="3">, y</font><font face="Times New Roman, Times, Serif" size="1"><sub>o</sub></font><font face="Times New Roman, Times, Serif" size="3">, z</font><font face="Times New Roman, Times, Serif" size="1"><sub>o</sub></font></i><font face="Times New Roman, Times, Serif" size="1"><sub></sub></font><font face="Times New Roman, Times, Serif" size="3">) - (<i>x</i></font><font face="Times New Roman, Times, Serif" size="1"><sub>sv</sub></font><font face="Times New Roman, Times, Serif" size="3">, <i>y</i></font><font face="Times New Roman, Times, Serif" size="1"><sub>sv</sub></font><font face="Times New Roman, Times, Serif" size="3">, <i>z</i></font><font face="Times New Roman, Times, Serif" size="1"><sub>sv</sub></font><font face="Times New Roman, Times, Serif" size="3">)] (and its derivatives) and are referred to as relative DGPS techniques.</font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table><table border="0" cellspacing="0" cellpadding="0"><tr><td rowspan="5"></td> <td colspan="3" height="12"></td> <td rowspan="5"></td></tr><tr><td colspan="3"></td></tr><tr><td></td> <td><font face="Times New Roman, Times, Serif" size="3"><i>5.8.1<br />Position-Space DGPS</i></font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table><table border="0" cellspacing="0" cellpadding="0"><tr><td rowspan="5"></td> <td colspan="3" height="12"></td> <td rowspan="5"></td></tr><tr><td colspan="3"></td></tr><tr><td></td> <td><font face="Times New Roman, Times, Serif" size="3">Consider the measurements</font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table><table border="0" cellspacing="0" cellpadding="0"><tr><td rowspan="5"></td> <td colspan="3" height="12"></td> <td rowspan="5"></td></tr><tr><td colspan="3"></td></tr><tr><td></td> <td><font face="Times New Roman, Times, Serif" size="3"><img src="722d81cf115bcc122ed0c764a4d6cce9.gif" border="0" alt="0172-02.GIF" width="307" height="19" /></font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table><table border="0" cellspacing="0" cellpadding="0"><tr><td rowspan="5"></td> <td colspan="3" height="12"></td> <td rowspan="5"></td></tr><tr><td colspan="3"></td></tr><tr><td></td> <td><font face="Times New Roman, Times, Serif" size="3"><img src="e48e4a1870c9fc0cd92eb8caf1d1b433.gif" border="0" alt="0172-03.GIF" width="306" height="17" /></font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table><table border="0" cellspacing="0" cellpadding="0"><tr><td rowspan="5"></td> <td colspan="3" height="12"></td> <td rowspan="5"></td></tr><tr><td colspan="3"></td></tr><tr><td></td> <td><font face="Times New Roman, Times, Serif" size="3">at the base and the rover, respectively. If the pseudoranges for the same set of satellites are measured at both locations, then a position correction can be determined at the known location x</font><font face="Times New Roman, Times, Serif" size="1"><sub>0</sub></font><font face="Times New Roman, Times, Serif" size="3"> for use by receivers at other locations.</font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table><table border="0" cellspacing="0" cellpadding="0"><tr><td rowspan="5"></td> <td colspan="3" height="12"></td> <td rowspan="5"></td></tr><tr><td colspan="3"></td></tr><tr><td></td> <td><font face="Times New Roman, Times, Serif" size="3">The base calculations, where x</font><font face="Times New Roman, Times, Serif" size="1"><sub>0</sub></font><font face="Times New Roman, Times, Serif" size="3"> is known, are described as</font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table><table border="0" cellspacing="0" cellpadding="0"><tr><td rowspan="5"></td> <td colspan="3" height="12"></td> <td rowspan="5"></td></tr><tr><td colspan="3"></td></tr><tr><td></td> <td><font face="Times New Roman, Times, Serif" size="3"><img src="34c3282aec167a239fa2aedbe032cb96.gif" border="0" alt="0172-04.GIF" width="348" height="22" /></font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table><table border="0" cellspacing="0" cellpadding="0"><tr><td rowspan="5"></td> <td colspan="3" height="12"></td> <td rowspan="5"></td></tr><tr><td colspan="3"></td></tr><tr><td></td> <td><font face="Times New Roman, Times, Serif" size="3"><img src="e6beec4f0d0e9986e929043f3d527f7c.gif" border="0" alt="0172-05.GIF" width="347" height="22" /></font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table><table border="0" cellspacing="0" cellpadding="0"><tr><td rowspan="5"></td> <td colspan="3" height="12"></td> <td rowspan="5"></td></tr><tr><td colspan="3"></td></tr><tr><td></td> <td><font face="Times New Roman, Times, Serif" size="3"><img src="0cd68d41b8923bb78e2a992fa790d45b.gif" border="0" alt="0172-06.GIF" width="346" height="22" /></font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table><table border="0" cellspacing="0" cellpadding="0"><tr><td rowspan="5"></td> <td colspan="3" height="12"></td> <td rowspan="5"></td></tr><tr><td colspan="3"></td></tr><tr><td></td> <td><font face="Times New Roman, Times, Serif" size="3">where </font><font face="Symbol" size="3"><i>d</i></font><font face="Times New Roman, Times, Serif" size="3">x</font><font face="Times New Roman, Times, Serif" size="1"><sub>0</sub></font><font face="Times New Roman, Times, Serif" size="3"> is identically zero since the linearization point x</font><font face="Times New Roman, Times, Serif" size="1"><sub>0</sub></font><font face="Times New Roman, Times, Serif" size="3"> is known. The term <img src="6cc3339c5bd01f51289017f76380fa3e.gif" border="0" alt="C0172-01.GIF" width="33" height="15" /> of Eq. (5.93) is the position-space DGPS correction that is broadcast by the base to all roving receivers. The minus sign in the previous sentence is necessary, as differential GPS corrections are typically defined to be added by</font><font face="Times New Roman, Times, Serif" size="3" color="#FFFF00"></font></td><td></td></tr><tr><td colspan="3"></td></tr><tr><td colspan="3" height="1"></td></tr></table></td></tr></table><p><font size="0"></font></p>聽 </td> </tr> <tr> <td align="left" width="30%" style="background: #EEF3E2"><a style="color: blue; font-size: 120%; font-weight: bold; text-decoration: none; font-family: verdana;" href="page_171.html">< previous page</a></td> <td id="ebook_next" align="center" width="40%" style="background: #EEF3E2"><strong style="color: #2F4F4F; font-size: 120%;">page_172</strong></td> <td align="right" width="30%" style="background: #EEF3E2"><a style="color: blue; font-size: 120%; font-weight: bold; text-decoration: none; font-family: verdana;" href="page_173.html">next page ></a></td> </tr> </table> </body> </html>⌨️ 快捷键说明
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