New "Indoor GPS" advertised - Page 1
Forum section: electronics / projects

author: JimRemington
author_rank: Regular Contributor
timestamp: September 03, 2015, 12:55:22 am
content: A company called Marvelmind has recently begun to market a new "indoor GPS", which works with radio and ultrasound beacons.http://www.marvelmind.com/They claim +/- 2 cm accuracy. I've looked through the website and there doesn't seem to be any hard performance data, just what seem to me to be rather unrealistic performance videos in idealized situations.I've challenged the manufacturer regarding the susceptibility of the system to interference from wall and obstacle reflections (as confounds the GPS system), but a representative claims that this is not an issue. See the ongoing discussion here:http://forum.pololu.com/viewtopic.php?f=2&t=10190This is a long awaited development and I'm disappointed by the initial presentation.

author: German_EE
author_rank: Super Contributor
timestamp: September 03, 2015, 07:28:11 am
content: I am not sure of the exact details but I have seen something similar used in large civil engineering projects. For a system like this to work you need exact placement of the beacons and then the mobile receiver references itself to the beacons rather than the satellite GPS signal as it is a much stronger signal.2cm accuracy? Possible. but a unit to achieve this normally costs thousands of dollars so I would be suspicious.

author: Kjelt
author_rank: Super Contributor
timestamp: September 03, 2015, 07:36:02 am
content: Philips has done this with their led fixtures. The position in regard to a few fixtures gives a few cm accuracy, enough to show a customer where their desired product is exactly located.

author: Berni
author_rank: Super Contributor
timestamp: September 03, 2015, 07:45:42 am
content: Now that is a pretty clever ideas from Philips.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 03, 2015, 08:03:09 am
content: ISTR recently reading about a wireless chipset that implements time-of-flight position measurement - can't immediately find it but looks like quite a few companies are working on it.

author: marvelmind
author_rank: Newbie
timestamp: September 03, 2015, 10:57:29 am
content: Hello guys,Yes, we do have a very interesting discussion with Jim in that forum. I try not to repeat what was said there, because you can follow it on that site.To add here:- Surely, we are not using radio for measuring the coordinates. Radio is used for synchronization, data transfer, system control and monitoring, etc.- Ultrasonic is used for coordinates. With ultrasonic to reach even sub-centimeter precision is not an impossible task. It is more than possible. But we are not producing a measurement device. That was not the task and we refrain from engaging in holy wars on the precisionThere are so many elements to discuss: air temperature, pressure. Static precision vs. differential precision. etc. It is not about that. Our solution is about providing sufficiently precise data for the robot to make decisions in the real environment.For a system like this to work you need exact placement of the beacons and then the mobile receiver references itself to the beacons rather than the satellite GPS signal as it is a much stronger signal.- sure! that is what we do:- You place the stationary beacons somewhere on the ceiling- The beacons automatically measure their relative position against each other and build the map of beacons- Then you freeze the map. It does not change and stay- Then mobile beacon measures its relative coordinates with very high precision against the stationary beaconsThat is all.- We are shipping a ready-to-use block for those who need it to install on robots, carts, vehicles. It can either trace those objects with high precision indoor or provide the location data to them to make the decision based on location. Thus, we call it Indoor "GPS" - just to simplify the understanding of the scheme and system logic. But it has nothing to do with the real GPS, of course. Instead of satellites we have our own beacons spread every 10-50 meters inside the building to provide the optimal coverage for area where robots move. In order to do that we recommend to place the beacons on ceiling or high in the walls. It creates the least obstruction for the mobile beacon on the robot.About radio based time-of-flight and UWB solutions. They are good. It like them a lot. Eventually, they will rule the world. However, currently you cannot buy them for the reasonable price with the performance we show. It is simply much more difficult and costly to achieve based on radio time-of-flight. Phase noise. Expensive crystals. Etc. But the technology develops quickly. Sooner or later it will come. But not yet. Not yet on the shelves. Thus, we are solving the practical problem with the practical way. Now.LED-assisted and other combined solutions are good. I very much support the idea of combining all sources of data and making the decision on the correlated data - not on any single source. But we are not competing with Phillips. They do compete with Bluetooth and WiFi based location solutions for terminals. Use cases are very different (humans vs. robots) and the precision is incomparable (+-2cm vs. ~1m at best). For the shopping mall to bring a human to the shelf 1-2 meter precision is sufficient. However, in order the robot to reach the right place and not to hit anything, the precision closer to <10cm is required. Our classical example is the door. If the robot is 60 cm wide and the door is 90 cm - these are your margins and requirements.Kind regards,Maxim

author: marvelmind
author_rank: Newbie
timestamp: September 03, 2015, 11:35:54 am
content: Hopefully, the other guys won't kill me, because I am publishing this ad-hock shot video without their permissionhttps://youtu.be/js2aq293BfIhttp://youtu.be/RGziB6nmr1MThe story behind the video:This was an ad-hock demo. It is shown as shot without any editing of any sort.We just dropped at the shop to see how the robots in real life work. It turned out the robot's SW development team was in the same building. Thus, we proposed to have an ad-hock demo of our system.We deployed it in 1 min simply by putting stationary beacons on the shelves. Nothing was planned, or tested, or prepared, or optimized beforehand. We just dropped to the shop, put the beacons on the shelves and put the mobile beacon on the top of the robot and checked how it world work in the absolutely unprepared environment.

author: JimRemington
author_rank: Regular Contributor
timestamp: September 03, 2015, 03:56:27 pm
content: QuoteMost of us are professionals, and look for an honest discussion of the downsides as well as the upsides of a new product.If your colleagues don't agree, they can expect criticism, or even to be ignored by the professional market.

author: marvelmind
author_rank: Newbie
timestamp: September 03, 2015, 04:04:34 pm
content: I hope so :-)By other guys I meant the guys with the robot. They are the customers. Not our guys, who developed the system.

author: marvelmind
author_rank: Newbie
timestamp: July 05, 2016, 01:31:22 pm
content: Hello colleagues,We recently shot a video of very precise (+-2cm) tracking using our system:https://youtu.be/gcjeuZMKpd8Mobile beacon is in hands and moving in square path of 35cm by 35cm. It is traced with very high precision (+-2cm) with the help of stationary 4 beacons that are surrounding the area and placed in the square of 17m by 17m (on stools).This is a demo of very precise tracking by Indoor "GPS" from Marvelmind Robotics (http://www.marvelmind.com).The system doesn't use GPS at all. It relies on 4 ultrasonic beacons and is intended to be used indoor for precise positioning for virtual reality (VR), autonomous robots and autonomous copters/drones.We shot demo outside simply because we could not find large 17x17m space indoor.Best regards,Maxim

author: Fred27
author_rank: Unknown
timestamp: July 05, 2016, 01:57:58 pm
content: Isn't "inside" the big problem though? You've sidestepped the issues of reflections by being outside.

author: 1design
author_rank: Regular Contributor
timestamp: July 05, 2016, 02:01:37 pm
content: The environment you are testing in looks pretty ideal for your technology. Have you tied using this around SMPS, active ballasts for CFL lighting and places where people obstruct the line of sight to your beacons? I would be interested in seeing the results from more real life situations. cm level accuracy is pretty common, even mm level accuracy in ultrasonic systems since sound travels very slowly compared to radio waves. I would be more concerned with range, object penetration in crowded environments etc.

author: Kilrah
author_rank: Unknown
timestamp: July 05, 2016, 02:21:41 pm
content: +1, what's the point of a demo where none of the caveats that would apply to a real-world use are present?

author: marvelmind
author_rank: Newbie
timestamp: July 06, 2016, 08:29:39 am
content: Hello colleagues,None of the technologies can serve in all possible environments. We are showing the capabilities of our system in the particular setup. Those, who need the capabilities, can check against their requirements and use it or not use it depending on the match :-)In this video we showed only very high precision tracking (+-2cm) in the commercially available system that you can buy right now and it will be delivered to you the next day. We didn't address the issue of reflections, range, shadows. In real life you can separate them with different techniques.Other comments about caveats:- Obviously, for any GPS-like system, the crucially important requirement is visibility of satellites or beacons, like in our system- If less than two beacons are visible, system won't work at all- If two beacons are available, you will get precise X,Y coordinates with fixed Z. It works well for rovers/forklifts, but won't work for VR headsets or copters- If three beacons are available, the system is fully functioning and X,Y,Z coordinates are awailable- Thus, solution for shadows is rather simple - (1) install enough beacons to avoid shadows - 4-6 beacons. If some beacons are obstructed, the system will take the info from the remaining beacons (2) place stationary and mobile beacons high enough to minimize probability of shadows- Regarding reflections. Absolutely correct. When the update rate is very high - ~25-50Hz and the room is very small - a few meters across and resonating - the reflections are hard to beat. Not impossible - we are finalizing testing of the new SW - but it is a hard technical task. We will show the video in those rooms too, when we are ready :-)But the reflections is an issue in special environment only:(1) very high update rate (25-50Hz). In 16Hz and the room of 5x5m - not a problem!(2) room has to be small(3) room has to be echoic - well reflecting walls.There are plenty of places that work very well even with small rooms and high update rate simply because the objects inside the room scatter the ultrasonic signal well enough and the walls are not so reflecting- Range is a completely different requirement. In this video we showed the range of 17x17m. We worked pretty well on up to 30x30m (up to 50m of direct distance between beacons) and soon we are going to publish new video about the range. One can't have very high update rate and very high range at the same time. However, it is possible to install many beacons and cover very high range with very high speed. But then it will be a matter of handling multiple mobile beacons in the same area at the same time with high speed. There is also a solution for that :-)So, in short, depending on your task, you can always find a reasonable solution.BR,Maxim

author: EEVblog
author_rank: Unknown
timestamp: July 06, 2016, 08:52:20 am
content: Quote from: marvelmind on July 06, 2016, 08:29:39 amTranslation: It's not going to work well in the real world, but we can't admit that.

author: marvelmind
author_rank: Newbie
timestamp: July 06, 2016, 08:53:36 am
content: BTW, I forgot other video for other caveats and solutions for them:https://youtu.be/TBTw1njQ7QY- demo of the small robot moving fully autonomously in the real room environment - with shadows, under the table, etc.Solution is simple: when ultrasonic signal is not available, the robot relies on other sensors - IMU+odometer. IMU+odometer is good enough for a couple of meters and then the coordinates are again adjusted with the help of our Indoor "GPS" system

author: marvelmind
author_rank: Newbie
timestamp: July 06, 2016, 08:55:59 am
content: Quote from: EEVblog on July 06, 2016, 08:52:20 am:-))Well, we are happy to work with all words: real and virtual :-)https://youtu.be/7EH7l02vE64

author: mubes
author_rank: Regular Contributor
timestamp: July 06, 2016, 08:01:11 pm
content: This indoor location thing is a problem that really interests me. We did something last year using rotating IR beacons around the edge of an 'arena' and a set of IR receivers on the vehicle that we were locating. As the beacon rotated it transmitted an angle plus an ID. The vehicle picked up that transmission from each of the beacons and, based on prior knowledge of where each turret was, could then triangulate its position.The system worked well, and let us try out a few new technologies like 3D printing. It gave around +/- 2 degree resolution and an effective positioning accuracy of 10mm in the arena we were working with. Having said that, it's not something I would be comfortable to take into production - far too many moving parts that would need maintenance....ultrasonic Delta Time of Flight is one approach that can avoid these limitations and will work in larger environments (especially if the temperature is reasonably constant). Olivetti had an optical system with emitters in the ceiling back in the early 2000s.Theres a paper downloadable fromhttps://drive.google.com/open?id=0B1bGB60-3LA8MTRYbkkwR1Q0U0Eif anyone’s interested. I'm currently playing with an idea to remove the need for the moving parts and improve the resolution...but it's hobby stuff, not paid work.DAVE