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Centimeter-Resolution GPS For Smartphones, VR, Drones
agent elevator writes: UT Austin engineers have come up with a software fix that corrects for the errors GPS has when using the tiny antennas on smartphones. They demoed it using a VR setup and got 2-cm accuracy. For now it runs on a separate processor from the smartphone, but they say they'll fix that. The demo appears to have been done on a rooftop. VR. Outside. On a roof. Doesn't seem like a good idea, does it?
Put a question in the summary that only makes sense if you RTFA. Nice.
It is unwise to ascribe motive
> They were also able to precisely track a virtual reality headset with the same precision.
One does not "precisely track" a VR headset with two centimeter resolution. I'll guess that they continued to use the IMU tracking that is built into the Samsung Gear VR, and they used it to display the tracking of external objects that were measured with two centimeter resolution.
The cell phone GPS antennae are tiny they catch the signal from the satellite and also many reflections. These reflections confuse the processor trying to fix the distance between itself and the satellite. They seem to have developed some signal processing algorithm that would remove these reflections. The article is skimpy on details.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
One of the main error sources for GPS is the propagation delay of signals that go through the atmosphere. An antenna can be in the exact same location but report a different location from day to day. This error is usually eliminated using http://en.wikipedia.org/wiki/Differential_GPS">Differential GPS.
Differential Global Positioning System (DGPS) is an enhancement to Global Positioning System that provides improved location accuracy, from the 15-meter nominal GPS accuracy to about 10 cm in case of the best implementations.
DGPS uses a network of fixed, ground-based reference stations to broadcast the difference between the positions indicated by the GPS (satellite) systems and the known fixed positions. These stations broadcast the difference between the measured satellite pseudoranges and actual (internally computed) pseudoranges, and receiver stations may correct their pseudoranges by the same amount. The digital correction signal is typically broadcast locally over ground-based transmitters of shorter range.
I see no mention of using differential GPS in this system.
Well, as long as you don't get closer than 2 centimeters from the edge.
That would be a good test for a GPS product; have someone navigate a dangerous area blindfolded using it's directions.
Right now I'm marking POI in the woods with GPS. 6M accuracy means I'm either on the money or I've got to move my ass 6m~ in every direction to find that specific spot.
No point marking it out in pretty colors to make it apparent to everybody else.
Does anyone have real experience with cm vertical precision from these products?
there's no fudging the data if it's a fail this way.
if this is supposed to be a new economy, how come they still want my old fashioned money?
The other important thing to note here is how well this could perform in combination with the wide-area augmentation system (WAAS), which corrects for atmospheric variation of signal travel time by using information the is generated by ground stations and broadcast by the satellites. WAAS isn't included in standard cheap GPS receivers, but can be had for little money, starting from $100 GPS receivers (and mandatory for certain aviation applications, for example).
Or the 2cm figure already include the use of WAAS?
if you are on a rooftop.
I have made my diploma in geodesy and if it would be so easy to get 2 cm with smartphone everywhere then it would be rolled out already. What they are showing is known and realized for like 6 years already, so nothing new. The positions problems will still persist on street level where like 99% of all peoples move and cars drive? The problem is not the antenna its the signal interruptions and multi-path reflections you have on the streets that you cannot simply fix with software as the amount of unique signals is limited.
It will actually be fixed by more satellites integrated into one software equalization equation and different signal modulation.
The first is taken care of by the GPS race between all superpowers entangled in it. By 2018 we will have around ~100 GP(S) Satellites in stationary or modular orbits. The only limiting factor here is the software of vendors which has to align and process the public signals GLONASS (RU), GALILEO (EU), GPS (US), BEIDU (CHINA), Indian and Japan signals. Which no one does atm, it is done at university level (for instance german TU Dresden).
The second one could improve position but just if all countries involved in GPS development and evolution would work together but actually they are not. Instead they compete for the frequencies ...very retarded game but that's another story.
What people need to understand is that most position software out there barely manage to get a better position out of GPS + GLONASS. There is nearly non that handles the four major systems because even these systems have, based on different earth models, different results for the same position.
https://radionavlab.ae.utexas.edu/images/stories/files/papers/ion2014Pesyna.pdf
We can be tracked with decimeter precision. Yay. I'm sure it won't be used against us. Carry on.
Won't someone pleeeaaase think of the children? Terrorists will use this to precisely place their mobile bombs. Bank-robbers will use this to attack gold repositories (see 'Die hard with a vengeance' and 'Stolen'). Once the sex dolls are invented, horny children will use this for cyber-sex. This technology must be banned immediately.
That would bring immediate improvements to GPS accuracy, which was initially intended as a remote terrain guidance system for nuclear tipped cruise missiles and submarine launched ICBMs.
(Yes, I know that then-President Clinton issued a directive to abolish Selective Availability in 2000, but that doesn't go anywhere near explaining why the average handheld still can't get better than twelve feet horizontal accuracy when a cruise missile can use GPS - travelling at 500mph - to pilot itself in through a particular window on a particular building).
Political debates have me rolling my eyes so much I think I got optical whiplash. I should sue. - Foamy The Squirrel
They use RTK technology. It doesn't rely on the same data as GPS or dGPS. It isn't new techology. And it wouldn't matter if the DOD screwed with the dGPS signal.
What is new is just what the article talked about. They have found a way, through 6 years of developing the software, to use a cheap antennae to capture signals. Prior to the software development, cheap antennae couldn't be used because they allowed for too much signal degradation. Their solution is their software, which they have apparently perfected to the point where it can recognize and correct or mistakes caused by the antennae.
My understanding of RTK is that it isn't useful for navigation, but is very useful and accurate in obtaining your position(while not moving) This is because it relies on a base station in addition to the other receiver.
Centimeter-Resolution GPS For Smartphones, VR, Drones
and for tracking you!
UT Austin engineers have come up with a software fix that corrects for the errors GPS has when using the tiny antennas on smartphones. They demoed it using a VR setup and got 2-cm accuracy.
Confused multiple test results there, didn't ya? The 2-cm results were achieved when they used a separate GPS antenna (not a smartphone GPS) stuck on top of the Samsung Gear in all the photos. The quality of antenna in that little black box is at least an order of magnitude better than those in typical smartphones.
Part of the problem that isn't addressed in the summary is that to have a cm accurate position you also need to have an oscillator that is accurate in the tens of picoseconds range.
From the article:
> The clock attached to the external front-end was an oven-controlled crystal oscillator (OCXO), which has much greater stability than the low-cost oscillators used to drive GNSS signal sampling within smartphones.
An OCXO is far more expensive than a smartphone manufacturer will happily absorb (~$30). It is also constantly heating the crystal so your battery life gets thrown out the window too.
GPS manufacturers very carefully select their cheaper TCXO chips in order to get nanosecond accuracy. Special tricks are used to get sufficient DAC resolution on the voltage control in order to steer them to the correct level. I have been out of the industry for several years but I would be shocked if there has been a 100x improvement in quality without hearing anything about it.
GPS Assist in cellphones use cell towers not satellites. Cell towers are in known GPS locations. Cell towers don't move. The US government can turn onSA all they wan't, and it won't any difference to a cellphone based GPS device. Unless of course they have the cell towers constantly updating their locations, which would be dumb, as I said they don't move.