the government has turned off it's disruptive signal to cause the inaccuracy in GPS without the differential. Anyone else heard the same thing. Supposedly this occured yesterday. Mark Johnson
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GPS Artical in the paper
I read the articial and it was suppose to be effective as of midnight last night. Artical said it should improve the accuracy of the unit by 10 folds with a variance of between 10 and 30 yards now. ...Larry...
I read the articial and it was suppose to be effective as of midnight last night. Artical said it should improve the accuracy of the unit by 10 folds with a variance of between 10 and 30 yards now. ...Larry...
Here's a clip on the deal.
President Clinton: Improving the Civilian Global Positioning System (GPS) THE WHITE HOUSE Office of the Press Secretary ___________________________________________________________________________ For Immediate Release May 1, 2000 President Clinton: Improving the Civilian Global Positioning System (GPS) May 1, 2000 "The decision to discontinue Selective Availability is the latest measure in an ongoing effort to make GPS more responsive to civil and commercial users worldwide. --This increase in accuracy will allow new GPS applications to emerge and continue to enhance the lives of people around the world." President Bill Clinton May 1, 2000 GPS IS A CRITICAL TECHNOLOGY FOR INDIVIDUALS AND BUSINESSES AROUND THE GLOBE. GPS is a dual-use system, providing highly accurate positioning and timing data for both military and civilian users. There are more than 4 million GPS users world wide, and the market for GPS applications is expected to double in the next three years, from $8 billion to over $16 billion. Some of these applications include: air, road, rail, and marine navigation, precision agriculture and mining, oil exploration, environmental research and management, telecommunications, electronic data transfer, construction, recreation and emergency response. GPS IS THE GLOBAL STANDARD. GPS has always been the dominant standard satellite navigation system thanks to the U.S. policy of making both the signal and the receiver design specification available to the public completely free of charge. NEW TECHNOLOGIES ENHANCE AMERICA'S NATIONAL SECURITY. The U.S. previously employed a technique called Selective Availability (SA) to globally degrade the civilian GPS signal. New technologies demonstrated by the military enable the U.S. to degrade the GPS signal on a regional basis. GPS users worldwide would not be affected by regional, security-motivated, GPS degradations, and businesses reliant on GPS could continue to operate at peak efficiency. GPS IMPROVED SIGNAL WILL BRING INSTANT BENEFITS TO MILLIONS OF GPS USERS. It?s rare that someone can press a button and make something you already own worth more, but that?s exactly what?s happening today. As of midnight tonight, all the people who?ve bought GPS receivers for boats, cars, or recreation will find that they are ten times more accurate. The technology that makes this extraordinary technology possible grows directly from our past research investments in basic physics, mathematics, and engineering supported from NSF, DARPA, NIST and other Federal agencies over a period of decades. GPS works because of super reliable atomic clocks -- no mechanical device could come close. These clocks resulted from Nobel-prize winning physics, and creative engineering that managed to package devices which once filled large physics laboratories into a compact, reliable, space-worthy device. The improved, non-degraded signal will increase civilian accuracy by an order of magnitude, and have immediate implications in areas such as: ? Car Navigation: Previously, a GPS-based car navigation could give the location of the vehicle to within a hundred meters. This was a problem, for example, in areas where multiple highways run in parallel, because the degraded signal made it difficult to determine which one the car was on. Terminating SA will eliminate such problems, leading to greater consumer confidence in the technology and higher adoption rates. It will also simplify the design of many systems (e.g., eliminate certain map matching software), thereby lowering their retail cost. ? Enhanced-911: The FCC will soon require that all new cellular phones be equipped with more accurate location determination technology to improve responses to emergency 911 calls. Removing SA will boost the accuracy of GPS to such a degree that it could become the method of choice for implementing the 911 requirement. A GPS-based solution might be simpler and more economical than alternative techniques such as radio tower triangulation, leading to lower consumer costs. ? Hiking, Camping, and Hunting: GPS is already popular among outdoor enthusiasts, but the degraded accuracy has not allowed them to precisely pin-point their location or the location of items (such as game) left behind for later recovery. With 20 meter accuracy or better, hikers, campers, and hunters should be able to navigate their way through unmarked wilderness terrain with increased confidence and safety. Moreover, users will find that the accuracy of GPS exceeds the resolution of U.S. Geological Survey (USGS) topographical quad maps. ? Boating and Fishing: Recreational boaters will enjoy safer, more accurate navigation around sandbars, rocks, and other obstacles. Anglers will be able to more precisely locate their favorite spot on a lake or river. Lobsterers will be able to find and recover their traps more quickly and efficiently. ? Increased Adoption of GPS Time: In addition to more accurate position information, the accuracy of the time data broadcast by GPS will improve to within 40 billionths of a second. Such precision may encourage adoption of GPS as a preferred means of acquiring Universal Coordinated Time (UTC) and for synchronizing everything from electrical power grids and cellular phone towers to telecommunications networks and the Internet. For example, with higher precision timing, a company can stream more data through a fiber optic cable by tightening the space between data packets. Using GPS to accomplish this is far less costly than maintaining private atomic clock equipment. Additional information about GPS and the Selective Availability decision is available online at the Interagency GPS Executive Board web site: http://www.igeb.gov
President Clinton: Improving the Civilian Global Positioning System (GPS) THE WHITE HOUSE Office of the Press Secretary ___________________________________________________________________________ For Immediate Release May 1, 2000 President Clinton: Improving the Civilian Global Positioning System (GPS) May 1, 2000 "The decision to discontinue Selective Availability is the latest measure in an ongoing effort to make GPS more responsive to civil and commercial users worldwide. --This increase in accuracy will allow new GPS applications to emerge and continue to enhance the lives of people around the world." President Bill Clinton May 1, 2000 GPS IS A CRITICAL TECHNOLOGY FOR INDIVIDUALS AND BUSINESSES AROUND THE GLOBE. GPS is a dual-use system, providing highly accurate positioning and timing data for both military and civilian users. There are more than 4 million GPS users world wide, and the market for GPS applications is expected to double in the next three years, from $8 billion to over $16 billion. Some of these applications include: air, road, rail, and marine navigation, precision agriculture and mining, oil exploration, environmental research and management, telecommunications, electronic data transfer, construction, recreation and emergency response. GPS IS THE GLOBAL STANDARD. GPS has always been the dominant standard satellite navigation system thanks to the U.S. policy of making both the signal and the receiver design specification available to the public completely free of charge. NEW TECHNOLOGIES ENHANCE AMERICA'S NATIONAL SECURITY. The U.S. previously employed a technique called Selective Availability (SA) to globally degrade the civilian GPS signal. New technologies demonstrated by the military enable the U.S. to degrade the GPS signal on a regional basis. GPS users worldwide would not be affected by regional, security-motivated, GPS degradations, and businesses reliant on GPS could continue to operate at peak efficiency. GPS IMPROVED SIGNAL WILL BRING INSTANT BENEFITS TO MILLIONS OF GPS USERS. It?s rare that someone can press a button and make something you already own worth more, but that?s exactly what?s happening today. As of midnight tonight, all the people who?ve bought GPS receivers for boats, cars, or recreation will find that they are ten times more accurate. The technology that makes this extraordinary technology possible grows directly from our past research investments in basic physics, mathematics, and engineering supported from NSF, DARPA, NIST and other Federal agencies over a period of decades. GPS works because of super reliable atomic clocks -- no mechanical device could come close. These clocks resulted from Nobel-prize winning physics, and creative engineering that managed to package devices which once filled large physics laboratories into a compact, reliable, space-worthy device. The improved, non-degraded signal will increase civilian accuracy by an order of magnitude, and have immediate implications in areas such as: ? Car Navigation: Previously, a GPS-based car navigation could give the location of the vehicle to within a hundred meters. This was a problem, for example, in areas where multiple highways run in parallel, because the degraded signal made it difficult to determine which one the car was on. Terminating SA will eliminate such problems, leading to greater consumer confidence in the technology and higher adoption rates. It will also simplify the design of many systems (e.g., eliminate certain map matching software), thereby lowering their retail cost. ? Enhanced-911: The FCC will soon require that all new cellular phones be equipped with more accurate location determination technology to improve responses to emergency 911 calls. Removing SA will boost the accuracy of GPS to such a degree that it could become the method of choice for implementing the 911 requirement. A GPS-based solution might be simpler and more economical than alternative techniques such as radio tower triangulation, leading to lower consumer costs. ? Hiking, Camping, and Hunting: GPS is already popular among outdoor enthusiasts, but the degraded accuracy has not allowed them to precisely pin-point their location or the location of items (such as game) left behind for later recovery. With 20 meter accuracy or better, hikers, campers, and hunters should be able to navigate their way through unmarked wilderness terrain with increased confidence and safety. Moreover, users will find that the accuracy of GPS exceeds the resolution of U.S. Geological Survey (USGS) topographical quad maps. ? Boating and Fishing: Recreational boaters will enjoy safer, more accurate navigation around sandbars, rocks, and other obstacles. Anglers will be able to more precisely locate their favorite spot on a lake or river. Lobsterers will be able to find and recover their traps more quickly and efficiently. ? Increased Adoption of GPS Time: In addition to more accurate position information, the accuracy of the time data broadcast by GPS will improve to within 40 billionths of a second. Such precision may encourage adoption of GPS as a preferred means of acquiring Universal Coordinated Time (UTC) and for synchronizing everything from electrical power grids and cellular phone towers to telecommunications networks and the Internet. For example, with higher precision timing, a company can stream more data through a fiber optic cable by tightening the space between data packets. Using GPS to accomplish this is far less costly than maintaining private atomic clock equipment. Additional information about GPS and the Selective Availability decision is available online at the Interagency GPS Executive Board web site: http://www.igeb.gov
new GPS accuracy
I read about this last night. SA was supposed to be turned off at 12:00 AM GMT. The first thing I did this morning was take my handheld (Magellan 2000XL) outside and turn it on. It promptly acquired 10 satellites, and the "estimated position error" was 3 feet! This value was previously (with SA on) around 150-200 feet. So, it seems they really have discontinued SA. Good news.
I read about this last night. SA was supposed to be turned off at 12:00 AM GMT. The first thing I did this morning was take my handheld (Magellan 2000XL) outside and turn it on. It promptly acquired 10 satellites, and the "estimated position error" was 3 feet! This value was previously (with SA on) around 150-200 feet. So, it seems they really have discontinued SA. Good news.
DGPS
DGPS = Differential GPS This is used to compensate for the timing differences that are in the system when SA (selective availablity) was turned on. Check out the article at www.igeb.gov for an excellent overview and all the terminology that you may or may not want to know.
DGPS = Differential GPS This is used to compensate for the timing differences that are in the system when SA (selective availablity) was turned on. Check out the article at www.igeb.gov for an excellent overview and all the terminology that you may or may not want to know.
What's Your EPE ?
A day of sailing yesterday gave me an EPE of 10-12' where it had been 50-70' most of the time. The government release said a ten-fold improvement was possible. Is anyone ready to throw away their DGPS receiver? Ken S/V Wouff Hong
A day of sailing yesterday gave me an EPE of 10-12' where it had been 50-70' most of the time. The government release said a ten-fold improvement was possible. Is anyone ready to throw away their DGPS receiver? Ken S/V Wouff Hong
Attabuoy!!
One snag of the discontinuance of SA is that now we are 100 times more likely to hit the buoys used as waypoints. Should we campaign fo its re-instatement.
One snag of the discontinuance of SA is that now we are 100 times more likely to hit the buoys used as waypoints. Should we campaign fo its re-instatement.
Not to mention...
... all the other boats heading for that exact same buoy, Now we'll all need radar if the fog rolls in!
... all the other boats heading for that exact same buoy, Now we'll all need radar if the fog rolls in!
Differential-Forget It
Did some tests today. Differential actual degraded the accuracy of the GPS Signal. We checked on 4 different Receivers. Now I ask! I was able to tell the GPS's that had outboard differentials that there no longer was a differential input. Great. But my Garmin 215 has no way to shut it off. I changed it to No Input and NMEA183 output like the others. No help. It automatically got the correct frequency and bit rate. I disconnected the antenna. But when you turn the receiver on, you have to hit ENTER when prompted to acknowledge that your (*&*( differential ain't sending a signal. What a bitch? Anyone got an answer? I'm contacting Garmin monday. chuckwolfe@mail.com
Did some tests today. Differential actual degraded the accuracy of the GPS Signal. We checked on 4 different Receivers. Now I ask! I was able to tell the GPS's that had outboard differentials that there no longer was a differential input. Great. But my Garmin 215 has no way to shut it off. I changed it to No Input and NMEA183 output like the others. No help. It automatically got the correct frequency and bit rate. I disconnected the antenna. But when you turn the receiver on, you have to hit ENTER when prompted to acknowledge that your (*&*( differential ain't sending a signal. What a bitch? Anyone got an answer? I'm contacting Garmin monday. chuckwolfe@mail.com
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