<br><br><div class="gmail_quote">No dia 28 de Setembro de 2011 13:02, João Gonçalves Costa <span dir="ltr"><<a href="mailto:joao.a.costa@ctt.pt">joao.a.costa@ctt.pt</a>></span> escreveu:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div lang="PT" link="blue" vlink="purple"><div><p class="MsoNormal"><span lang="EN-US">New satellite could revolutionize battlefield communications<u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">The National Journal reports that the Naval Research Laboratory plans to launch an experimental $75 million satellite this week that U.S. ground forces can use for on-the-move communications with standard military handheld or backpack radios.<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p><p class="MsoNormal"><span lang="EN-US">The Tactical Satellite-4 (or TacSat-4) will zoom around Earth in an elliptical orbit at altitudes ranging from 435 miles to 7,470 miles, keeping the spacecraft far closer to the ground than the 22,000-mile orbit of geostationary communications satellites, according to the Operationally Responsive Space Office at Kirtland Air Force Base, N.M., which funded the launch and first six months of use.<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p><p class="MsoNormal"><span lang="EN-US">Michael Hurley, head of spacecraft development for the Naval Research Lab, said in an e-mail from the TacSat-4 launch site in Kodiak, Alaska, that the low orbits will allow ground forces for the first time to communicate with a military satellite using omnidirectional antennas on their radios while on the move, rather than stopping to set up a satellite antenna.<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p><p class="MsoNormal"><span lang="EN-US">TacSat-4, Hurley said, will support troops in Afghanistan equipped with An/PRC-148 and AN-PRC-152 handheld radios, manufactured by Thales and Harris respectively, and the Harris AN/PRC-117 backpack radio, as well as the AN/PSC-5 portable satellite terminal from Raytheon used by special-forces units. <u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p><p class="MsoNormal"><span lang="EN-US">Hurley said that all these radios communicate with TacSat-4 in one of 10 channels in the 240-318 MHz band, which is also used by the Defense Department's geostationary ultra-high frequency satellite constellation.<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p><p class="MsoNormal"><span lang="EN-US">Read the full National Journal article New Satellite Could Revolutionize Battlefield Communications <u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><a href="http://www.nationaljournal.com/nationalsecurity/new-satellite-could-revolutionize-battlefield-communications-20110927" target="_blank">http://www.nationaljournal.com/nationalsecurity/new-satellite-could-revolutionize-battlefield-communications-20110927</a> <u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p></div></div><br>_______________________________________________<br>
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