Heartman8 Posted October 25, 2009 Share Posted October 25, 2009 What is the most accurate GPS? Quote Link to comment
LinXG Posted October 25, 2009 Share Posted October 25, 2009 The most accurate handheld I'm aware of is the Trimble GeoXH. With the Tornado external antenna accuracy is rated at 10 centimeters. Quote Link to comment
Motorcycle_Mama Posted October 25, 2009 Share Posted October 25, 2009 How much money are you willing to spend? Quote Link to comment
geo blazer Posted October 25, 2009 Share Posted October 25, 2009 The most accurate handheld I'm aware of is the Trimble GeoXH. With the Tornado external antenna accuracy is rated at 10 centimeters. I'd love to see a price on one of these. I googled it and can't find a price anywhere. Must be pricey? Quote Link to comment
Heartman8 Posted October 25, 2009 Author Share Posted October 25, 2009 Is there a correlation between accuracy and the # of satelites the GPS uses? Quote Link to comment
LinXG Posted October 25, 2009 Share Posted October 25, 2009 (edited) Price is just over $4000.00US without the external antenna The Trimble unit is not typical of what a geocacher is likely to use or even needs. The accuracy isn't so much based on the number of satellites but rather their positions relative to your GPSR. The better the geometry the better the accuracy. Also keep in mind that the published accuracy for the GPS satellite system is about 10 meters. With WAAS you may see 5 meters. You also have to factor in signal degradation due to tree cover, tall buildings and so forth. Just about any modern GPSR will work equally well as far as satellite reception and accuracy are concerned. Manufacturers mostly promote ease of use and features over any technical merits their units may offer. Edited October 25, 2009 by LinXG Quote Link to comment
+Walts Hunting Posted October 25, 2009 Share Posted October 25, 2009 One of the rules of measuring is you can't measure something more accurately than the instrument used to make it. If you had that one you would be measuring 10cm accuracy to find something that the placer marked with 15' plus error radius. It is generally thought that the most accurate one for caching was the old 60CS with the SIRFIII chip. However this hobby is not about detailed accuracy. When you get close it is time to put the gps away and use your senses. I believe that the most accurate Garmin currently is the Colorado. It has the Oregon beat hands down because of the helix antenna. I have cached with a buddy who has one and me with my Oregon. We did one the other day under tree cover. He went right to the correct tree while mine took me over 20 feet away. He is consistently better plus his arrow actually turns when he does instead of pointing in the wrong direction for long periods of time. On the other hand the touch screen is awesome. Just wish they had allowed an external antenna. On the other hand I generally find them by expanding the search area Quote Link to comment
+naviguesser74 Posted October 25, 2009 Share Posted October 25, 2009 I was with a survey one day and his GPS was showing accuracy at 3/8". I believe the cost was $80,000. I am using a Magellan MMCX and with post-processing, we get <1'. These are hobby-type units that would be good for geocaching. Quote Link to comment
Suscrofa Posted October 25, 2009 Share Posted October 25, 2009 I was with a survey one day and his GPS was showing accuracy at 3/8". I believe the cost was $80,000. I am using a Magellan MMCX and with post-processing, we get <1'. These are hobby-type units that would be good for geocaching. ANd how many feet is 3/8" ? And we are in the twenty first century ! Quote Link to comment
+user13371 Posted October 26, 2009 Share Posted October 26, 2009 (edited) ...how many feet is 3/8" ? 3/8 of an inch is 1/32 of a foot. 3/8" = 9.525mm 1' = 304.8mm Edited October 26, 2009 by lee_rimar Quote Link to comment
NordicMan Posted October 26, 2009 Share Posted October 26, 2009 "Super high accuracy GPSr's" would indeed be very useful in lots of other usage areas, but it IMO isn't applicable to Geocaching.. Really guys, think about it. Would you enjoy this pastime as much as you do now if the hide/find accuracy was one foot or less? If EVERY cache hidden was found as easily as following the GPSr arrow until the distance counter read 0 and, voila, look down (or sometimes up lol) and THERE'S the cache! That sounds like a great way of making this fun pastime incredibly boring... Quote Link to comment
Motorcycle_Mama Posted October 26, 2009 Share Posted October 26, 2009 Yep, it's totally not applicable to Geocaching. But the question in the OP was "What is the most accurate GPS?" with no additional stipulation as to the use nor the price range. Quote Link to comment
Suscrofa Posted October 26, 2009 Share Posted October 26, 2009 ...how many feet is 3/8" ? 3/8 of an inch is 1/32 of a foot. 3/8" = 9.525mm 1' = 304.8mm And how accurate is this conversion ? Because for survey, are you still using the antique inch or the less antique one defined as 25.4mm exactly ? Quote Link to comment
+julianh Posted October 26, 2009 Share Posted October 26, 2009 ...how many feet is 3/8" ? 3/8 of an inch is 1/32 of a foot. 3/8" = 9.525mm 1' = 304.8mm And how accurate is this conversion ? Because for survey, are you still using the antique inch or the less antique one defined as 25.4mm exactly ? Yes, if we're going to get down to sub-inch accuracy, perhaps we need our GPSrs to display in base units smaller than the inch - how about distance to destination in "barleycorns"? After 1066, 1 inch was equal to 3 barleycorn, which continued to be its legal definition for several centuries, with the barleycorn being the base unit. http://en.wikipedia.org/wiki/Inch (Personally, I'll stick with the metric system - we already have millimetres, and we can go down to microns or nanometres when the precision of these things gets significantly better! ) Quote Link to comment
LinXG Posted October 27, 2009 Share Posted October 27, 2009 I think a super high accuracy gps would make for a very fun spectator sport. Imagine placing a cache with your typical Garmin/Magellan/Lowrance unit and then sitting on a nearby hillside watching the antics of a someone repeatedly coming to within an inch of the wrong place looking for a nano when you've left an ammo can. I agree with NordicMan, a lot of the fun of geocaching comes from discovering to new places, getting some exercise and solving a puzzle. Quote Link to comment
Suscrofa Posted October 27, 2009 Share Posted October 27, 2009 Yes, if we're going to get down to sub-inch accuracy, perhaps we need our GPSrs to display in base units smaller than the inch - how about distance to destination in "barleycorns"? After 1066, 1 inch was equal to 3 barleycorn, which continued to be its legal definition for several centuries, with the barleycorn being the base unit. http://en.wikipedia.org/wiki/Inch (Personally, I'll stick with the metric system - we already have millimetres, and we can go down to microns or nanometres when the precision of these things gets significantly better! ) Just a clarification, there is only one unit of length, the meter, kilo, mega, centi, micro ... are just a way to represent factor of 10 but do not define "new" units (we use a decimal based numbering system) ! This is not often understood. Lack of proper education in science and technology. Even Garmin eng. as they let you set the GPS to display in meter or kilometer ! This is a non sense, they should always try to display with the maximum number of significant digits and adjust the display accordingly to show km or m ! It is annoying for ex. for distance as you really loose accuracy if you set the display to km then come closer to your target. Of course one can't beat the screwing up of using imperial units ! Quote Link to comment
+GPSlug Posted October 27, 2009 Share Posted October 27, 2009 Just a clarification, there is only one unit of length, the meter, kilo, mega, centi, micro ... are just a way to represent factor of 10 but do not define "new" units (we use a decimal based numbering system) ! This is not often understood. Lack of proper education in science and technology. Even Garmin eng. as they let you set the GPS to display in meter or kilometer ! This is a non sense, they should always try to display with the maximum number of significant digits and adjust the display accordingly to show km or m ! It's a matter of semantics, but I would say that if there is any conversion necessary, no matter how trivial, the units have changed. If you are recording distances in a list, and they are all the same unit, you can specify that unit at the top of the column. You can't do that if some are in m and some in km. If you need to specify it, it's a different unit. It is annoying for ex. for distance as you really loose accuracy if you set the display to km then come closer to your target. But if you are driving and need to glance at the display to know how far the next turn is, you may not want to need to squint at the units identifier. Of course one can't beat the screwing up of using imperial units ! They can be annoying, but they keep you on your toes. You always need to be rigorous about your units. You can't just get lazy because it's all "metric". If you're told a vehicle is going "35", you'd better know whether that's in km/h or m/s. It's not that big of a leap from there to imperial units. Quote Link to comment
Suscrofa Posted October 28, 2009 Share Posted October 28, 2009 Just a clarification, there is only one unit of length, the meter, kilo, mega, centi, micro ... are just a way to represent factor of 10 but do not define "new" units (we use a decimal based numbering system) ! This is not often understood. Lack of proper education in science and technology. Even Garmin eng. as they let you set the GPS to display in meter or kilometer ! This is a non sense, they should always try to display with the maximum number of significant digits and adjust the display accordingly to show km or m ! It's a matter of semantics, but I would say that if there is any conversion necessary, no matter how trivial, the units have changed. If you are recording distances in a list, and they are all the same unit, you can specify that unit at the top of the column. You can't do that if some are in m and some in km. If you need to specify it, it's a different unit. It is annoying for ex. for distance as you really loose accuracy if you set the display to km then come closer to your target. But if you are driving and need to glance at the display to know how far the next turn is, you may not want to need to squint at the units identifier. Of course one can't beat the screwing up of using imperial units ! They can be annoying, but they keep you on your toes. You always need to be rigorous about your units. You can't just get lazy because it's all "metric". If you're told a vehicle is going "35", you'd better know whether that's in km/h or m/s. It's not that big of a leap from there to imperial units. It is NOT a matter of semantics ! If your earn 1K dollars, the unit is still the dollars !!! Please read the definitions related to these prefix. Google gives tons of URL plus the NIST site. Even ebay knows that: http://reviews.ebay.com/Mega-kilo-milli-an...000000008751267 No big deal to mix km and m !!!! Are you familiar with them ? On a car display, if you see distance 1.02 km you know it is one km twenty m ! Anyone knows that, at least outside of the US ! Common usage for car is km/h so 35 implies 35km/h. It is why most speed limit panels don't show the unit. True, in Europe some guy tried to contest a police ticket based on the fact that the legal units being the m, kilogramm, s, A, 50 would mean 50m/s !!! He lost because of what I just said above. Oh by the way, metric is now mandatory in medecine as too many errors screwing up conversion from pound to kg and therefore prescritpion errors as they are computed in mg per kg of body mass. We are in the 21° century ! Quote Link to comment
+julianh Posted October 28, 2009 Share Posted October 28, 2009 We are in the 21° century ! When did the degree become a unit of measuring time? (And is that Celsius or kelvin?) Quote Link to comment
Motorcycle_Mama Posted October 28, 2009 Share Posted October 28, 2009 It's Julian time. Quote Link to comment
+sinbad58 Posted November 13, 2009 Share Posted November 13, 2009 The most accurate handheld I'm aware of is the Trimble GeoXH. With the Tornado external antenna accuracy is rated at 10 centimeters. Ifr You read the Specs for The Trimble GeoXH it states that Accuracy within that range is accuired only with optional Antenna, that also needs External Correction Data from Fixed Radio Transmitter. A sort of Local " Differiental Correction System " A very Expensive piece of equipment to use in Geocaching "Following Clipped from Trimble Leaflet " Real-time positioning H-Star8 with internal antenna (within a VRS network, or <80 km). . Subfoot (<30 cm) H-Star8 with optional Tornado antenna Short baseline (within a VRS network, or <30 km). 10 cm Long baseline (30–80 km). Subfoot (<30 cm) Code corrections (SBAS1 or external correction source). Submeter Postprocessed positioning H-Star8 with internal antenna (<80 km, or 3 bases within 200 km). Subfoot (<30 cm) H-Star8 with optional Tornado antenna Short baseline (<30 km). 10 cm Long baseline (30–80 km, or 3 bases within 200 km). 20 cm Code postprocessed. Submeter "End of Clipped text" Regards "Sinbad58" Quote Link to comment
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.