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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_258</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_257.html">< previous page</a></td> <td id="ebook_previous" align="center" width="40%" style="background: #EEF3E2"><strong style="color: #2F4F4F; font-size: 120%;">page_258</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_259.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 258</font></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">In this section, the pseudorange and phase measurements are modeled 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="28222c0918775246ffee99ad2c3a9334.gif" border="0" alt="0258-01.GIF" width="425" height="16" /></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="dcbf0cf68f3d506c0930a89479443bca.gif" border="0" alt="0258-02.GIF" width="426" height="32" /></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 <i>E</i></font><i><font face="Times New Roman, Times, Serif" size="1"><sub>i</sub></font></i><font face="Times New Roman, Times, Serif" size="1"><sub></sub></font><font face="Times New Roman, Times, Serif" size="3"> represents the ionospheric errors, <i>E</i></font><font face="Times New Roman, Times, Serif" size="1"><sub>cm</sub></font><font face="Times New Roman, Times, Serif" size="3"> denotes the cumulative effect of ephemeris, satellite clock, tropospheric, and selective availability errors, and </font><font face="Symbol" size="3">h</font><font face="Times New Roman, Times, Serif" size="3">, MP, mp, <i>N</i>, and </font><font face="Symbol" size="3">z</font><font face="Times New Roman, Times, Serif" size="3"> are used as defined as in Chap. 6. Ionospheric errors are represented separately from the other common-mode errors since these errors affect the pseudorange and phase measurements differently.</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">In single-differencing techniques, <i>E</i></font><font face="Times New Roman, Times, Serif" size="1"><sub>cm</sub></font><font face="Times New Roman, Times, Serif" size="3"> and <i>E</i></font><i><font face="Times New Roman, Times, Serif" size="1"><sub>i</sub></font></i><font face="Times New Roman, Times, Serif" size="1"><sub></sub></font><font face="Times New Roman, Times, Serif" size="3"> will be small, but dependent on the baseline distance. In addition, receiver clock error is contained in </font><font face="Symbol" size="3">r</font><font face="Times New Roman, Times, Serif" size="3">(<i>t</i>). In double-differencing techniques, <i>E</i></font><font face="Times New Roman, Times, Serif" size="1"><sub>cm</sub></font><font face="Times New Roman, Times, Serif" size="3"> and <i>E</i></font><i><font face="Times New Roman, Times, Serif" size="1"><sub>i</sub></font></i><font face="Times New Roman, Times, Serif" size="1"><sub></sub></font><font face="Times New Roman, Times, Serif" size="3"> are also small and dependent on the baseline distance. In this case, </font><font face="Symbol" size="3">r</font><font face="Times New Roman, Times, Serif" size="3">(<i>t</i>) represents the base station-to-user position vector.</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>7.4.1<br />Full Error Model</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">To construct a full error model for a carrier-smoothed-code GPS-aided-INS application, let x</font><font face="Times New Roman, Times, Serif" size="1"><sub><i>n</i></sub></font><font face="Times New Roman, Times, Serif" size="3"> denote the INS error state, x</font><font face="Times New Roman, Times, Serif" size="1"><sub>cm</sub></font><font face="Times New Roman, Times, Serif" size="3"> denote the common-mode error states, x</font><font face="Times New Roman, Times, Serif" size="1"><sub><i>i</i></sub></font><font face="Times New Roman, Times, Serif" size="3"> denote the ionospheric error state, x</font><font face="Times New Roman, Times, Serif" size="1"><sub>MP</sub></font><font face="Times New Roman, Times, Serif" size="3"> denote the code multipath error state, x</font><font face="Times New Roman, Times, Serif" size="1"><sub><i>N</i></sub></font><font face="Times New Roman, Times, Serif" size="3"> denote the integer ambiguity error state, and let mp, </font><font face="Symbol" size="3">h</font><font face="Times New Roman, Times, Serif" size="3">, and </font><font face="Symbol" size="3">z</font><font face="Times New Roman, Times, Serif" size="3"> be modeled as white-noise processes. The full system error model is then</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="b3da51fb134191bd9e94eb9d1ae90a8c.gif" border="0" alt="0258-03.GIF" width="447" height="84" /></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="ed0f02961a95ea549c8aa080e59ed158.gif" border="0" alt="0258-04.GIF" width="451" height="86" /></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 advantage of such a full implementation is that the applied Kalman filter would be able to take advantage of the full range measurement provided by the pseudorange and the high-accuracy dynamic information provided by the phase. In practical terms, the phase gives very accurate information about the change in user-to-satellite range, but is not by itself useful in determining absolute position (unless <i>N</i> is determined). Noisy estimates of absolute position can</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_257.html">< previous page</a></td> <td id="ebook_next" align="center" width="40%" style="background: #EEF3E2"><strong style="color: #2F4F4F; font-size: 120%;">page_258</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_259.html">next page ></a></td> </tr> </table> </body> </html>⌨️ 快捷键说明
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