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1 Antenna, 3 Dimensions
February 15, 2010

1 Antenna, 3 Dimensions

SNUGL team members: From left to right, Byungjoon Park (BJ Hobby Craft), Jihoon Kim, Prof. Changdon Kee, Am Cho, Bosung Kim, Dongkeon Kim, Noha Park, Sanghoon Jeon, and Donghwan Bae

GPS has been widely used as a navigation sensor for numerous applications including unmanned aerial vehicles (UAVs). Many researchers have devoted considerable efforts to expand the role of GPS in guidance, navigation and control to determining an aircraft’s attitude. That would enable us to use a GPS receiver as a sensor for an automatic control system as well as a navigation sensor.

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Wide-Area RTK

Wide-Area RTK

A common assumption in real-time kinematic (RTK) techniques is that the differential ionospheric delay between a GNSS transmitter and each of the roving or reference receivers is negligible. However, increased position uncertainty — spatial decorrelation — is usually allocated to the baseline receivers as baseline distances increase.

A refinement of this assumption comes with the network RTK (NRTK) using a set of permanent receivers to mitigate atmospheric dependent effects, such as the ionospheric delay, over distance.

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Taking Positioning Indoors

Taking Positioning Indoors

Wireless local area networks (WLANs), popularly known as Wi-Fi, were originally designed for data applications. Over the past decade or so, WLAN infrastructure has been implemented for high-speed wireless Internet access in homes, “hot-spots,” university campuses, and corporate buildings. Hundreds of millions of Wi-Fi access points (APs) are deployed in major urban areas worldwide.

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GNSS Hotspots | January 2010
January 19, 2010

GNSS Hotspots | January 2010

One of 12 magnetograms recorded at Greenwich Observatory during the Great Geomagnetic Storm of 1859
1996 soccer game in the Midwest, (Rick Dikeman image)
Nouméa ground station after the flood
A pencil and a coffee cup show the size of NASA’s teeny tiny PhoneSat
Bonus Hotspot: Naro Tartaruga AUV
Pacific lamprey spawning (photo by Jeremy Monroe, Fresh Waters Illustrated)
“Return of the Bucentaurn to the Molo on Ascension Day”, by (Giovanni Antonio Canal) Canaletto
The U.S. Naval Observatory Alternate Master Clock at 2nd Space Operations Squadron, Schriever AFB in Colorado. This photo was taken in January, 2006 during the addition of a leap second. The USNO master clocks control GPS timing. They are accurate to within one second every 20 million years (Satellites are so picky! Humans, on the other hand, just want to know if we’re too late for lunch) USAF photo by A1C Jason Ridder.
Detail of Compass/ BeiDou2 system diagram
Hotspot 6: Beluga A300 600ST

1. FOLLOW THAT TRASH!  
Seattle, Washington and Cambridge, Massachusetts
√ Trash/Track, a Seattle project created by MIT’s SENSEable City Lab, tracked a representative sample of city throwaways using GPS and CDMA cell-tower trilateration. Tagged items phoned home to an MIT server which mapped their progress in real time. Hint: Stuff doesn’t go away. http://senseable.mit.edu/trashtrack/

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By Alan Cameron
Three GLONASS-M Satellites Launched in December, All Operational as of February 1
January 18, 2010

Three GLONASS-M Satellites Launched in December, All Operational as of February 1

(UPDATED FEB. 1, 2010) Russia got its GNSS program back on track with the December 14 launch of three modernized GLONASS-M satellites — resuming a schedule interrupted by problems with a navigation payload on an in-orbit spacecraft. A Proton launcher took the trio of satellites into orbit at 1038 GMT (5:38 a.m. EST) from the Baikonur Cosmodrome in central Kazakhstan.The first of the new spacecraft began transmitting signals on January 10. Another went live on January 24 and the third was declared operational in a February 1 ITAR-TASS press release. 

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More of the Same

More of the Same

A favorite movie scene: Yul Brynner as Rameses II in The Ten Commandments sternly asserting, “So let it be written; so let it be done.”

With a similar peremptory gesture, the U.S. Coast Guard (USCG) published its notice in the January 7 Federal Register certifying that abolition of the Loran-C system would not adversely affect the safety of maritime navigation and ordering its decommissioning beginning February 8.

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