GPS World, August 2012
TIMING Infrastructure FIGURE 7 Oscilloscope and Synchrowave screen at about 870 seconds point 4 in Figure 3 FIGURE 8 Oscilloscope and Synchrowave screen at about 1370 seconds point 5 in Figure 3 D JHQHUDWRU WULS Q WKH WHVW GHVFULEHG LQ WKH SUHYLRXV VHFWLRQ D R RIIVHW WKH WKUHVKROG IRU WKH KLFRDVHQ QJRVWXUD OLQN ZDV LQGXFHG E WKH VSRRIHU DERXW V DIWHU FDSWXULQJ WKH WDUJHW UHFHLYHU DV VHHQ LQ LJXUHV DQG PDOHIDFWRU FRXOG HYHQ OHDG WKH SKDVH DQJOH RII LQ WKH RSSRVLWH GLUHFWLRQ VD R EHIRUH FXWWLQJ ERWK N9 WUDQVPLVVLRQ OLQHV QVWHDG RI FDXVLQJ D JHQHUDWRU WR XQQHFHVVDULO WULS WKLV ZRXOG SUHYHQW 308V IURP WULSSLQJ WKH JHQHUDWRU ZKHQ UHTXLUHG DQG SRWHQWLDOO FDXVH GDPDJH WR WKH JHQHUDWRU RU UHPDLQLQJ WUDQVPLVVLRQ OLQHV H RQG WULSSLQJ D VLQJOH JHQHUDWRU WKHUH LV SRWHQWLDO IRU WKH HIIHFWV RI WKH DWWDFN WR SURSDJDWH WKURXJK WKH JULG DQG FDXVH FDVFDGLQJ IDXOWV DFURVV WKH JULG 2QH H DPSOH RI WKLV W SH RI FDVFDGLQJ IDLOXUH LV WKH 1RUWKHDVW EODFNRXW OWKRXJK WKLV EODFNRXW GLG QRW LQYROYH 308V RU D VSRRILQJ DWWDFN LW GHPRQVWUDWHV KRZ DQ DSSURSULDWHO WDUJHWHG DWWDFN DJDLQVW 308V XVHG IRU FRQWURO RQ WKH SRZHU JULG FRXOG FDXVH ODUJH VFDOH EODFNRXWV WKDW RULJLQDWH ZLWK D VLQJOH JHQHUDWRU RU WUDQVPLVVLRQ OLQH WULS 2Q XJ DW S P D N9 WUDQVPLVVLRQ OLQH LQ 2KLR EHJDQ WR VDJ IURP LQFUHDVHG IORZ RI HOHFWULF SRZHU KHQ WKH OLQH VDJJHG WRR FORVH WR D WUHH LW FDXVHG D VKRUW WR JURXQG DQG WULSSHG RIIOLQH 7KLV LV VRPHWKLQJ WKDW KDSSHQV IDLUO IUHTXHQWO RQ WKH PDVVLYH 8 6 HOHFWULFDO JULG DQG LV XVXDOO HDVLO GHDOW ZLWK RZHYHU WKH WULSSLQJ RI WKDW OLQH LQ QRUWKHUQ 2KLR EHJDQ D FDVFDGH RI IDLOXUHV WKDW LQ D OLWWOH PRUH WKDQ DQ KRXU OHG WR D QHDU WRWDO SRZHU ORVV IRU PRUH WKDQ PLOOLRQ SHRSOH LQ WKH QRUWKHDVWHUQ 8 6 DQG SDUWV RI DQDGD 7KH EODFNRXW LV HVWLPDWHG WR KDYH FRVW DSSUR LPDWHO ELOOLRQ IRU RQO IRXU GD V RI SRZHU ORVV 7KLV OHG WKH HSDUWPHQW RI QHUJ DQG WKH 1RUWK PHULFDQ OHFWULF 5HOLDELOLW RUSRUDWLRQ 1 5 WR IXQG DQG SXVK IRU DQ LPSURYHG VPDUW JULG ZLWK V QFKURSKDVRU WHFKQRORJ DV D PDMRU FRPSRQHQW V SUHYLRXVO SRLQWHG RXW 308V DUH KLJK VSHHG UHDO WLPH V QFKURQL HG PHDVXUHPHQW GHYLFHV XVHG WR GLDJQRVH WKH KHDOWK RI WKH HOHFWULFLW JULG LWK V QFKURSKDVRU GDWD HOHFWULF XWLOLWLHV FDQ XVH H LVWLQJ SRZHU PRUH HIILFLHQWO DQG SXVK PRUH SRZHU WKURXJK WKH JULG ZKLOH UHGXFLQJ WKH OLNHOLKRRG RI SRZHU GLVUXSWLRQV OLNH EODFNRXWV 6 QFKURSKDVRU PHDVXUHPHQWV DUH EHLQJ ORRNHG DW WR UHGXFH WKH OLNHOLKRRG RI IDOVH DQG LQDSSURSULDWH WULJJHUV RI WUDQVPLVVLRQ V VWHP FLUFXLW EUHDNHUV WKDW SURWHFWLYHO VKXW GRZQ HOHFWULFDO IORZ DQG FRQWULEXWH WR FDVFDGLQJ EODFNRXWV RZHYHU 36 VSRRILQJ SRVHV D VLJQLILFDQW WKUHDW WR WKHVH REMHFWLYHV IRU 308V DQG FDQ PDNH V QFKURSKDVRU EDVHG FRQWURO WKH FDXVH IRU WKHVH HYHQWV LQVWHDG RI WKH FXUH Conclusions 6SRRILQJ SRVHV D WKUHDW WR WKH LQWHJULW RI V QFKURSKDVRU PHDVXUHPHQWV VSRRIHU FDQ LQWURGXFH D WLPH RIIVHW LQ WKH WLPH UHIHUHQFH UHFHLYHU WKDW SURYLGHV WKH WLPLQJ VLJQDO IRU D 308 ZLWKRXW KDYLQJ SK VLFDO DFFHVV WR WKH UHFHLYHU LWVHOI 7KLV SURGXFHV D FRUUHVSRQGLQJ SKDVH RIIVHW LQ WKH V QFKURSKDVRU GDWD FRPLQJ IURP WKDW 308 7HVWV GHPRQVWUDWHG WKDW D 308 FRXOG EH PDGH WR YLRODWH WKH 6WDQGDUG IRU V QFKURSKDVRUV LQ DERXW PLQXWHV IURP WKH VWDUW RI D VSRRILQJ DWWDFN V 308 XVDJH FRQWLQXHV WR JURZ WKURXJKRXW WKH ZRUOG 308V ZLOO LQFUHDVLQJO EH XVHG IRU DXWRPDWLF FRQWURO SXUSRVHV LQVWHDG RI MXVW JULG PRQLWRULQJ 7KH WHVWV GHVFULEHG KHUH GHPRQVWUDWH WKDW D VSRRIHU FRXOG FDXVH FRQWURO VFKHPHV WR IDOVHO WULS D JHQHUDWRU Q WKH SUHVHQFH RI RWKHU H DFHUEDWLQJ IDFWRUV WKLV FRXOG OHDG WR D FDVFDGH RI IDXOWV DQG D ODUJH VFDOH EODFNRXW DANIEL P SHEPARD is pursuing M S and Ph D degrees in aerospace engineering at the University of Texas at Austin He is a member of the Radionavigation Laboratory TODD E HUMPHREYS is an assistant professor of aerospace engineering and engineering mechanics at the University of Texas at Austin and director of the Radionavigation Laboratory He received a Ph D in aerospace engineering from Cornell University AARON A FANSLER serves as cyber critical infrastructure protection CCIP program manager for Northrop Grumman Information System He obtained a Masters degree from Capitol College in information assurance and is currently working on a Ph D in that field GPS World August 2012 www gpsworld com 38
You must have JavaScript enabled to view digital editions.