Cell phones pinpoint locations
<p><span word="Download">Download</span></p><p><span word="In">In</span> <span word="November">November</span> 1993, <span word="student">student</span> <span word="Jennifer">Jennifer</span> <span word="Koon">Koon</span> <span word="was">was</span> <span word="kidnapped">kidnapped</span> <span word="and">and</span> <span word="killed">killed</span> <span word="in">in</span> <span word="New">New</span> <span word="York">York</span> <span word="state">state</span> <span word="in">in</span> <span word="the">the</span> <span word="United">United</span> <span word="States">States</span>.</p><p><span word="Before">Before</span> <span word="her">her</span> <span word="death">death</span>, <span word="the">the</span> 18-<span word="year">year</span>-<span word="old">old</span> <span word="college">college</span> <span word="sophomore">sophomore</span> <span word="and">and</span> <span word="daughter">daughter</span> <span word="of">of</span> <span word="a">a</span> <span word="New">New</span> <span word="York">York</span> <span word="state">state</span> <span word="assemblyman">assemblyman</span> <span word="managed">managed</span> <span word="to">to</span> <span word="call">call</span> 911, <span word="but">but</span> <span word="police">police</span> <span word="could">could</span> <span word="not">not</span> <span word="determine">determine</span> <span word="her">her</span> <span word="position">position</span> <span word="from">from</span> <span word="the">the</span> <span word="cellphone">cellphone</span> <span word="signal">signal</span>.</p><p><span word="Three">Three</span> <span word="years">years</span> <span word="later">later</span>, <span word="the">the</span> <span word="public">public</span> <span word="safety">safety</span> <span word="network">network</span> <span word="Location">Location</span>-<span word="based">based</span> <span word="Services">Services</span> <span word="was">was</span> <span word="established">established</span>, <span word="allowing">allowing</span> <span word="authorities">authorities</span> <span word="to">to</span> <span word="locate">locate</span> <span word="users">users</span> <span word="through">through</span> <span word="radio">radio</span> <span word="signals">signals</span>.</p><p><span word="Now">Now</span>, <span word="in">in</span> <span word="China">China</span>, <span word="nearly">nearly</span> <span word="two">two</span> <span word="decades">decades</span> <span word="later">later</span>, <span word="such">such</span> <span word="services">services</span> <span word="are">are</span> <span word="not">not</span> <span word="far">far</span> <span word="away">away</span>.</p><p>"<span word="LBS">LBS</span> <span word="is">is</span> <span word="nothing">nothing</span> <span word="new">new</span>. <span word="The">The</span> <span word="reason">reason</span> <span word="we">we</span> <span word="could">could</span> <span word="not">not</span> <span word="develop">develop</span> <span word="an">an</span> <span word="LBS">LBS</span> <span word="in">in</span> <span word="China">China</span> <span word="until">until</span> <span word="now">now</span> <span word="is">is</span> <span word="that">that</span> <span word="the">the</span> <span word="Internet">Internet</span> <span word="on">on</span> <span word="mobiles">mobiles</span> <span word="only">only</span> <span word="became">became</span> <span word="popular">popular</span> <span word="in">in</span> <span word="the">the</span> <span word="past">past</span> <span word="few">few</span> <span word="years">years</span>," <span word="said">said</span> <span word="Shi">Shi</span> <span word="Chuang">Chuang</span>, <span word="a">a</span> <span word="professor">professor</span> <span word="at">at</span> <span word="Wuhan">Wuhan</span> <span word="University">University</span> <span word="and">and</span> <span word="director">director</span> <span word="of">of</span> <span word="the">the</span> <span word="National">National</span> <span word="Engineering">Engineering</span> <span word="Research">Research</span> <span word="Center">Center</span> <span word="for">for</span> <span word="Satellite">Satellite</span> <span word="Positioning">Positioning</span> <span word="System">System</span>.</p><p>"<span word="With">With</span> <span word="LBS">LBS</span>, <span word="we">we</span> <span word="can">can</span> <span word="integrate">integrate</span> <span word="information">information</span> <span word="on">on</span> <span word="people">people</span> ... <span word="and">and</span> <span word="things">things</span>, <span word="so">so</span> <span word="that">that</span> <span word="we">we</span> <span word="can">can</span> <span word="dig">dig</span> <span word="out">out</span> <span word="business">business</span> <span word="value">value</span>," <span word="he">he</span> <span word="said">said</span>.</p><p><span word="As">As</span> <span word="a">a</span> <span word="result">result</span>, <span word="life">life</span> <span word="can">can</span> <span word="be">be</span> <span word="made">made</span> <span word="more">more</span> <span word="convenient">convenient</span>, <span word="such">such</span> <span word="as">as</span> <span word="through">through</span> <span word="live">live</span> <span word="monitoring">monitoring</span> <span word="of">of</span> <span word="traffic">traffic</span> <span word="congestion">congestion</span> <span word="or">or</span> <span word="monitoring">monitoring</span> <span word="dangerous">dangerous</span> <span word="and">and</span> <span word="poisonous">poisonous</span> <span word="goods">goods</span>.</p><p><span word="However">However</span>, <span word="nothing">nothing</span> <span word="can">can</span> <span word="be">be</span> <span word="accomplished">accomplished</span> <span word="without">without</span> <span word="a">a</span> <span word="highly">highly</span> <span word="accurate">accurate</span> <span word="positioning">positioning</span> <span word="system">system</span>.</p><p><span word="Paul">Paul</span> <span word="Zandbergen">Zandbergen</span>, <span word="an">an</span> <span word="associate">associate</span> <span word="professor">professor</span> <span word="at">at</span> <span word="the">the</span> <span word="University">University</span> <span word="of">of</span> <span word="New">New</span> <span word="Mexico">Mexico</span>'<span word="s">s</span> <span word="geography">geography</span> <span word="department">department</span>, <span word="did">did</span> <span word="an">an</span> <span word="accuracy">accuracy</span> <span word="survey">survey</span> <span word="on">on</span> <span word="positioning">positioning</span> <span word="systems">systems</span> <span word="on">on</span> <span word="the">the</span> 3<span word="G">G</span> <span word="iPhone">iPhone</span> <span word="in">in</span> 2009.</p><p><span word="Results">Results</span> <span word="showed">showed</span> <span word="Wi">Wi</span>-<span word="Fi">Fi</span> <span word="locations">locations</span> <span word="using">using</span> <span word="this">this</span> <span word="phone">phone</span> <span word="had">had</span> <span word="an">an</span> <span word="average">average</span> <span word="error">error</span> <span word="of">of</span> 74 <span word="meters">meters</span> <span word="for">for</span> 58 <span word="observations">observations</span>, <span word="failing">failing</span> <span word="to">to</span> <span word="meet">meet</span> <span word="the">the</span> <span word="published">published</span> <span word="accuracy">accuracy</span> <span word="specifications">specifications</span>, <span word="while">while</span> <span word="cellular">cellular</span> <span word="positioning">positioning</span> <span word="using">using</span> <span word="this">this</span> <span word="phone">phone</span> <span word="had">had</span> <span word="a">a</span> <span word="median">median</span> <span word="error">error</span> <span word="of">of</span> 600 <span word="meters">meters</span> <span word="for">for</span> 64 <span word="observations">observations</span>.</p>
页:
[1]