In today’s FORT 130 lab we tested the consistency of GPS measurements. At five selected points the initial UTM coordinate was recorded. Then an averaged waypoint with at least 30 measurements was recorded. The location difference or error was calculated in Excel. Below is a map of the test site.
The measurement of waypoints with GPS should be improved by averaging. The differences between the initial reading and averaged waypoint ranged from 2 to 18 meters, with an average of 7.5 meters.
Points 2, 3 and 4 were taken under forest canopies, although leaves have already fallen. Points 1, 5 and 6 were taken in open conditions. The differences were greater in open versus forest canopy conditions, although not consistently. The consistency results and calculations can be seen here: GPS-Consistency-Worksheet-Linehan.pdf.
Yesterday a Russian rocket crashed near Hawaii with three satellites on board shortly after launch. The satellites were destined to be part of the GLONASS satellite navigation, which operates similarly to the American NAVSTAR GPS or the European Galileo.
Follow this link to a Yahoo News article quoting from an AFP article where Russian Prime Minister Putin stresses the importance of GLONASS to offset US influence. He wants all Russian cars to be equipped with GLONASS. In another article he said that he wanted cell phones sold in Russia to use GLONASS instead of NAVSTAR. He would also heavily tax units that use the American navigation system. See the Reuters article.
I was under the impression that the Russians wanted to sell their system to the world, which makes sense. I was surprised, but not that much, they would institute such a restrictive policy at home.
In this Russian article, the launch failure is attributed to a programming error, which reminds me of the mathematical units error that caused the loss of a NASA Mars explorer vessel. You have to check the programming!The article also has pictures of the launch.
The launch failure shouldn’t hurt the systems, which is already operational over all of Russia with 26 satellites in service.
Posted in FORT 130
The recent shelling of Yeonpyeong Island by North Korean forces during military maneuvers by the South Korean military has been top international news. In an area where tensions are running so high, any action may be the trigger for a new war.
I am amazed how close the island is to the North Korean mainland. No wonder there is controversy over who owns it. One of the interviews on TV showed a South Korean fisherman. He said that fishing is the only industry on the island and he needs to get back to work as soon as possible. I sincerely hope that he gets his wish.
This map shows wayponts, a track, and a route.
View GPS Data in FORT 130 in a larger map
While discussing lines of latitude (parallels) in my forest mapping class I started thinking about famous historic parallels. In order of latitude from south to north, here are the ones I could think of.
- Vietnamese Demilitarized Zone
- Korean Demilitarized Zone
- Mason Dixon Line
- 49th Parallel
Posted in FORT 130
Since 1884 the meridian through the Royal Observatory in Greenwich has been considered the prime meridian for measuring longitudes around the world. However, there have been many other alternatives. Currently the Royal Mecca Clock Tower is being constructed in Saudi Arabia. One of the tower’s giant clocks was started for testing at the beginning of this year’s month of Ramadan.
Islamic scholars are indeed arguing that moving the prime meridian to Mecca would be historically more accurate and be used by a greater number of people. It’s unlikely that such a move would occur any time soon. But it does point out that the prime meridian is not a geographic location, like the equator or the poles. It is a reference point agreed to by convention.
Click here for articles on this subject that I have found.
Talk about people who need a map. Two french tourists (Guillaume Combot and Enora Nedelec) are in the middle of a three-year hike from Cape Town, South Africa to Paris. They are now near Khartoum Sudan. Check out their web site here. (It is in French, but there is an english version, which looks like a machine translation.)
They must have access to computers as they are posting updates and photos. There are also some videos. There is a fascinating one showing how Guillaume cut pieces from a water bottle to reinforce his crumbling sneakers.
I hope they write a book or make a documentary film of this adventure. In addition to all the other adventures they are having, I am curious how they are navigating. Do they use a GPS? Are they using road maps? I know from experience that good road maps are hard to come by and are expensive in many African countries. This is an adventure I definitely want to keep an eye on.
This version of the map uses the Google Earth plug-in. If you don’t have the plug-in installed it will show up as a 2D map.
This hike took about an hour and a half. It’s great on a sunny afternoon as the hill has a westerly aspect.