Hi guys,
I have a question. I was just browsing around and trying to understand distance measurement sensors. I found what I think is a general overview over the different sensor types (http://zuff.info/RangeFindersComp_E.html). However, I was wondering if anybody has a little more knowledge in this area. I was wondering if there is a sensor type that can measure the distance of the sensor to a base station (or better yet three base stations). My objective is find the sensor's position eventually in a three-space, probably within 40ft radius (open space). Sonar works with sound waves, and the environment is rather noisy therefore I think it will influence the measurements a lot. The problem I see with IR/Laser measurement is that the sensor will constantly be moving and might have a small object blocking the direct line between base stations and the sensor.
So I was wondering - if you take SIM cards and triangulate their location using the cell towers, you will get a location using a network connection, correct? But these kind of positioning sensors are not listed. Would there be a way to use the same principle scaled down to the the smaller area of approx 5000ft^2? Maybe through some kind of Wifi? The important thing to me is to find that position in a three dimensional space.
Does anybody have any suggested where I should look further or read upon? It's like my little pet project that was spinning in my head for a little I appreciate any feedback!
All the best,
Phill
edit: If the sensors sent out a signal, and three different base stations measure the signal strength at any given time, would that be enough to pinpoint the sensors location?
Related
Hi. New here. I'm wondering if there is an application that will make my Touch Pro display the actual signal strength at the top rather than the bars.
I've done a fair amount of searching and haven't seen anything much but maybe I'm not looking in the right place.
Thanks!
nactownag said:
Hi. New here. I'm wondering if there is an application that will make my Touch Pro display the actual signal strength at the top rather than the bars.
I've done a fair amount of searching and haven't seen anything much but maybe I'm not looking in the right place.
Thanks!
Click to expand...
Click to collapse
Actually, it's not quite that simple. The display of 'bars' is actually the result of a fairly complicated algorithm, that takes into account signal strength, quality, and transmission diagnostics. And it isn't the same for all providers either. Each cell provider installs their own application/algorithm to determine and display bars. There was an article about this on the Wired site a few months (or so) ago. And here's one that's similar...
http://www.switched.com/2008/01/15/what-do-cell-phone-signal-bars-really-really-mean/
Hey! I'm new to SGS captivate and to the whole gps thing and do have a question about the basic concepts (how does it work, how does it track you, etc etc) of gps on SGS. Is there some kind of manual or faq I can refer to? Google'ing doesn't work for me in this case and xda search gives no clear results.
Try Wikipedia
Wikipedia and Garmin and other sites have a lot of detail. Your question is so broad I am not sure I can answer it.
Basically, the phone has a special chip inside that is dedicated to deciphering the radio signals broadcast by an array (it's called a "constellation") of satellites. By locking onto several of these signals it can make available a stream of data to installed applications on the phone to interpret. The data can represent your position in space (x, y, and z) as well as time. Your location can now be displayed on a map (Google Maps is a fine example), as well as your speed (usually restricted to on the ground).
Important things:
Hardware: The GPS chip, the antenna
Software: The Samsung driver that interfaces the chip to the Android environment, the special applications that interpret and display this data in a useful fashion.
Performance: How accurate is your location? How quickly does the GPS acquire a "lock"? How well does the software/GPS track your changing location?
It appears that there is a wide variation in performance and expectations among the owners of these Samsung Galaxy S phones. My personal expectations have been based on several prior phones, and I find the Captivate performance to vary widely and randomly, depending on software builds/settings and the physical environment.
I have used this same phone with a cheap external Bluetooth GPS and found the performance dramatically better. I am not sure if the phone native GPS performance will ever live up to my expectations.
mmarquis said:
Wikipedia and Garmin and other sites have a lot of detail. Your question is so broad I am not sure I can answer it.
Basically, the phone has a special chip inside that is dedicated to deciphering the radio signals broadcast by an array (it's called a "constellation") of satellites. By locking onto several of these signals it can make available a stream of data to installed applications on the phone to interpret. The data can represent your position in space (x, y, and z) as well as time. Your location can now be displayed on a map (Google Maps is a fine example), as well as your speed (usually restricted to on the ground).
Important things:
Hardware: The GPS chip, the antenna
Software: The Samsung driver that interfaces the chip to the Android environment, the special applications that interpret and display this data in a useful fashion.
Performance: How accurate is your location? How quickly does the GPS acquire a "lock"? How well does the software/GPS track your changing location?
It appears that there is a wide variation in performance and expectations among the owners of these Samsung Galaxy S phones. My personal expectations have been based on several prior phones, and I find the Captivate performance to vary widely and randomly, depending on software builds/settings and the physical environment.
I have used this same phone with a cheap external Bluetooth GPS and found the performance dramatically better. I am not sure if the phone native GPS performance will ever live up to my expectations.
Click to expand...
Click to collapse
Thank you for the detailed info. Well, wiki does have some common overall thoughts about the gps system but I was more interested in SGS realization of it. I guess your post made it a little more clear for me, thanks!
My wife and I are big into Geocaching now. Can anyone tell me what rom/kernel has been the most accurate them? It doesn't matter to me what version of android I use. I am finding that NFX 2.1 gets me to the relative position but acts a little crazy at times. As far as CM6, I am finding it to be even less accurate. I'd like to avoid buying a handheld gps if I can.
I have also tried downloading the GPS Status & Toolbox from the market and reset and downloaded GPS assist data. While this works sometimes, I find that it often freezes the GPS temporarily.
Any thoughts guys? Thanks in advance.
P.S. I have already searched the forum for answers and have not found anything specific to what I am looking for.
Any stable rom/kernel combination will be as accurate as any other, in any given situation. The algorithm used to determine GPS positioning is imbedded in the radio software, and is independent of the rom or kernel.
I've been using Google MyTracks for a long time, on many different roms, to record my mountain bike rides deep in the woods. I've not seen any accuracy differences between any of the roms/kernels I've used. I've observed that accuracy is highly dependent on the quality of signal I'm getting from the satellites ... deep in the woods, my position might be off 20 feet or more, but out in the open prairie I'll be accurate to 3 feet or less.
bernard_photography said:
My wife and I are big into Geocaching now. Can anyone tell me what rom/kernel has been the most accurate them? It doesn't matter to me what version of android I use. I am finding that NFX 2.1 gets me to the relative position but acts a little crazy at times. As far as CM6, I am finding it to be even less accurate. I'd like to avoid buying a handheld gps if I can.
I have also tried downloading the GPS Status & Toolbox from the market and reset and downloaded GPS assist data. While this works sometimes, I find that it often freezes the GPS temporarily.
Any thoughts guys? Thanks in advance.
P.S. I have already searched the forum for answers and have not found anything specific to what I am looking for.
Click to expand...
Click to collapse
The accuracy of the GPS is actually very dependent on hardware. Where you get assistance in accuracy is using the cell tower positions to help your location results in combination with the GPS receiver itself. That has a lot more to do with a radio than a kernel. I would try to make sure your using the most recent radio, if it doesnt work better, then flash an older one. There are several geocaching apps on the market that help you with your GPS coordinates. There is no perfect science to geocaching, and your phone GPS will never be as accurate as a dedicated mobile GPS unit. That being said, I use my phone for it, and the extra time it takes to find the cache is part of the enjoyment of doing it in the first place!! Good luck!
Hey all,
I'm using Zeus 6.22 and I've run into the same problem on every rom i've tried so far. GPS works, but the moment i get in the car/bus/whatever, GPS reception gets very, very poor and usually cuts out completely. Is there anything i can do to improve it or is this a hardware limitation? I've tried using google maps, copilot navigator, igo and sygic, all software seem to be having the same problem...
Use Zeus tweaker and CM7 config gps
Tap to Black Hell... 2
It's a hardware limitation which unfortunately happens on portable devices like our Optimus Black.
Since the hardware on the OB is pretty weak (in comparison to larger devices), the GPS on our phone MUST have line of sight with the sky, ultimatly meaning it has line of sight with the orbiting satellite.
That would be why it cuts out on the bus or whatever.
I'm not sure that there is a work around for this like there is with 3G data speeds but if you or somebody has an answer, I too would greatly appreciate the feedback as i suffer from the same problems as well.
EDIT: I don't think GPS config settings will change the strength of the signal between the phone or alter the interference as a result of dynamic environments.
With the December 2019 update for the Pixel 4 and Pixel 4 XL, users now have access to the L5 (US) and E5a (EU) satellite signals. Let's see what you're getting for accuracy.
It seems, to me, that Android has imposed a hard-coded minimum limit on the horizontal accuracy. I initially blamed an app, but it seems like it's Android which has gone from 6ft accuracy to 9.9ft (2012-2013, if I recall correctly) to now 12.4ft (2017-2018) horizontal accuracy. That doesn't make sense to me, unless it's really just v2 of Selective Availability, now client-side. I remember reading, somewhere, about another dual frequency gnss phone receiving l5/e5a signals, but the article stated that those weren't actually being used in measurements. GPSTest shows "U" for them, so I'm not sure why accuracy is no better than before, unless the software is limiting it.
Here's the gold-standard everyone has used for a few years (it's "GPSTest", not to be confused with the countless "GPS Test" apps):
https://play.google.com/store/apps/details?id=com.android.gpstest
It's not consistent in receiving L5/E5a, and that may be because it's heavily overcast in my area of Texas today. My screenshots are from indoors, on this overcast day. "Force full GNSS measurements" is enabled in developer options, although I've not noticed any subjective difference it makes, through all of the months I've used it.
Two screenshots:
https://imgur.com/a/6W6PeKC
Do you mind uploading your gps.conf file? And what carrier do you have?
Jon8RFC said:
With the December 2019 update for the Pixel 4 and Pixel 4 XL, users now have access to the L5 (US) and E5a (EU) satellite signals. Let's see what you're getting for accuracy.
It seems, to me, that Android has imposed a hard-coded minimum limit on the horizontal accuracy. I initially blamed an app, but it seems like it's Android which has gone from 6ft accuracy to 9.9ft (2012-2013, if I recall correctly) to now 12.4ft (2017-2018) horizontal accuracy. That doesn't make sense to me, unless it's really just v2 of Selective Availability, now client-side. I remember reading, somewhere, about another dual frequency gnss phone receiving l5/e5a signals, but the article stated that those weren't actually being used in measurements. GPSTest shows "U" for them, so I'm not sure why accuracy is no better than before, unless the software is limiting it.
Here's the gold-standard everyone has used for a few years (it's "GPSTest", not to be confused with the countless "GPS Test" apps):
https://play.google.com/store/apps/details?id=com.android.gpstest
It's not consistent in receiving L5/E5a, and that may be because it's heavily overcast in my area of Texas today. My screenshots are from indoors, on this overcast day. "Force full GNSS measurements" is enabled in developer options, although I've not noticed any subjective difference it makes, through all of the months I've used it.
Two screenshots:
https://imgur.com/a/6W6PeKC
Click to expand...
Click to collapse
slyyke said:
Do you mind uploading your gps.conf file? And what carrier do you have?
Click to expand...
Click to collapse
Attached with appended .txt extension so that it would upload without having to be zipped.
Google store edition Pixel 4 on Visible (Verizon Wireless's in-house MVNO).
The GPS accuracy here post December update seems to have degraded as well. I had hoped that dual frequency performance would improve both the reliability of reception and overall accuracy but that has not been the case, while it is currently acceptable the position "walks" quite a bit so lane-level positioning seems as distant as ever.
Kalman filters seem to reduce this error but I haven't had the time to thoroughly test. I have always suspected that the inclusion of additional sensor input(barometer, gyroscope and accelerometer) for a IMU approach would assist.
Let's hope additional updates will address this including use of the Galileo GNSS constellation.