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Supposedly, this company provides circuit boards and equipment so that you can rather cheaply create your own RTK (Real Time Kinematics) system. RTK is used in $8K drones to do mapping. These "toys" apparently provide 1cm "accuracy" and 0.1mm "precision". It is the precision that is important to appraisers. If you had such a device, you could go around the house and get the exact GPS coordinates for all corners of the house and interior rooms - feed them into a calculator and get measurements with 0.2mm precision.
The SparkFun GPS-RTK-SMA raises the bar for high-precision GPS and is the latest in a line of powerful RTK boards featuring the ZED-F9P module from u-blox.
www.sparkfun.com
You will also need to create a base station.
If you want to buy a base station + RTK, it will likely cost you about $6K or so. But they are getting cheaper. This is where we are headed. The future is approaching very quickly.
With highly accurate GPS signals, we can program robots to move around in the house with high degrees of accuracy. We will soon have robots that can move from room to room doing chores like making beds, cleaning and so on. But do do this, we will also need highly accurate floor plans of homes that show all entrances and exists to and from each room, that names rooms, that indicates the location of stairs, - and so on.
Moasure is a revolutionary new measuring technology that measures by sensing its position and movement in three dimensions. It uses inertial motion sensors to measure distance, height, level, angle, area and volume in a single measurement, simply by moving from one point to another.
www.moasure.com
Moasure is not GPS enabled (yet, don't know if they plan that) but is gaining on getting their device useable. I use it on occasion and it has come a long way in the last couple of years. The biggest problem I have with it is that the sensitivity (no doubt intertwined with its accuracy) is so particular that if you bump it too hard or move too fast, etc, it tends to record an error. Early on, that meant starting over, but they have been tweaking the app to allow you to continue, and it just flags the suspected measurement. I used it on an oddball, southwest-style adobe home earlier this year and it was the only way I could come close to getting the unique angles close enough to close the sketch. I have also used it to map the steep terrain on a lot I own, rather than surveying a grid and taking individual elevations at each grid point. It actually does a good enough job in that application that I expect to rely on it for creating a building site on that steep slope.
Moasure is a revolutionary new measuring technology that measures by sensing its position and movement in three dimensions. It uses inertial motion sensors to measure distance, height, level, angle, area and volume in a single measurement, simply by moving from one point to another.
www.moasure.com
Moasure is not GPS enabled (yet, don't know if they plan that) but is gaining on getting their device useable. I use it on occasion and it has come a long way in the last couple of years. The biggest problem I have with it is that the sensitivity (no doubt intertwined with its accuracy) is so particular that if you bump it too hard or move too fast, etc, it tends to record an error. Early on, that meant starting over, but they have been tweaking the app to allow you to continue, and it just flags the suspected measurement. I used it on an oddball, southwest-style adobe home earlier this year and it was the only way I could come close to getting the unique angles close enough to close the sketch. I have also used it to map the steep terrain on a lot I own, rather than surveying a grid and taking individual elevations at each grid point. It actually does a good enough job in that application that I expect to rely on it for creating a building site on that steep slope.
Provides fast, reliable, and accurate GPS and GLONASS position information up to 5 devices including the iPad, Android, Windows and more.
tinyurl.com
It connects to the Dual app on the iPhone via bluetooth.
Actually, I went outside with it today to see how accurate it was. I measured the front two corners of my property - which should be 60' across (lot is 60'x100'). Then threw the coordinates into
to get the distance. It came out to 60.2'. It measured one corner at 37.653054 / -122.488412. Well one digit or 0.000001 is about 3.5 inches. So, that is the best precision you can get. And initially it will take up to 29 seconds to get the first reading then maybe 15-20 seconds on each subsequent reading. - So that is a somewhat slow process.
The way a typical base station/RTK rover works is that you give the base station time to set the coordinates from the satellites - which essentially gives you your GPS accuracy to, they say, up to 1 cm. This is with radio corrections overlaying the GPS signals. --- Then the rover communicates with the base station to get its coordinates with respect to the base station. Since it is so much closer to the base station than the satellites it will give you a relative accuracy that is VERY precise, i.e. apparently sub-millimeter. And so the differences in the RTK readings will give you very exact length measurements.
Discover Emlid’s high-precision GNSS / GPS receivers for RTK surveying. Emlid Reach receivers deliver the accuracy and reliability professionals need, even in challenging locations.
emlid.com
A drone like the RTK Phantom also communicates with a base station you set up. So, they can provide very very precise mapping information - and are used for example to calculate how much material is in piles of rock, grain, or other material - as well as create ortho maps of sites or 3D mappings of buildings.
As Moasure One is the first device of its kind, there are bound to be questions and things you need help with. That’s why, here at Moasure, we have created a whole list of help articles covering how to get the best out of your Moasure ONE. Choose from the list below or scroll down to read...
www.moasure.com
It is stating the accuracy as +/- 0.5% and the range of measurement as 3 in to 1000 ft. That is odd. The accuracy would be +/- so many inches per point. So, they should be saying the point accuracy is +/- so many inches or cm. Double that to get the accuracy for a given length regardless of the length. So, if that device they have is similar to the SkyPro, which I bet it is, then the accuracy goes out to six decimal places which is 3.5 inches. - Thus they have 3 in-1000ft. But then, it would really be 6in-1000f in length. 0.5% of 1000 ft is 5 ft accuracy on length. That is not very good, really. So, their specs don't really make sense and can't be trusted. I would bet the device they sell is just a SkyPro - which only guarantees +/-2.5 meters on GPS accuracy to the real GPS coordinates. Of course, if you are measuring length rather than exact location, it is the precision or relative accuracy you are interested in - and that is the 3.5 inches on each end or 7 inches total.
Also note that you have to stop up to 4 seconds at each point on your route. - That is not bad. But then again,
"Time: your measurement movement is taking too long. Each movement MUST be completed in 3-4 seconds. The longer this takes, the faster the error grows. For larger measurements, pause the measurement every 3-4 seconds, by placing your device very still against a solid object for a second, then continue the measurement."
Do you see what they are telling you? You are not allowed to walk too far. Given that, it then doesn't take so much time for the GPS to catch up with you. Walk 15 feet and stop, ..... So, it's a somewhat slow process.
Save some money and get a SkyPro. You can use it for driving in areas where iPhone GPS doesn't work. It is very good and reliable. To get greater precision than you get with SkyPro or Moasure - you need to get the surveyor type Emlid Base Station and RTK Rover poles ($2,600 x2=$5600 +/-). Note: Get two Emlid RS2+ rovers and use one rover as a base station and the other as the rover.
www.sparkfun.com
