GPS Altitude - Touch Pro, Fuze ROM Development

Did anybody of you recognized a problem with the altitude computation. My raphael discloses me 40-60 meters to high.
I tried different Radio Roms and GPS soft´s.
Well is just can assume it, because my alternative GPS-receiver discloses me much lower and of course, this can also be wrong.

apokryphus said:
Did anybody of you recognized a problem with the altitude computation. My raphael discloses me 40-60 meters to high.
I tried different Radio Roms and GPS soft´s.
Well is just can assume it, because my alternative GPS-receiver discloses me much lower and of course, this can also be wrong.
Click to expand...
Click to collapse
AFAIK height measurements with GPS are highly inaccurate. This due to most applications focussing on the 2d grid, and the fact that height would probably need more satellites as a 3th dimension would needed to be calculated.

EvilWhiteDragon said:
AFAIK height measurements with GPS are highly inaccurate. This due to most applications focussing on the 2d grid, and the fact that height would probably need more satellites as a 3th dimension would needed to be calculated.
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Click to collapse
Thats right and indeed it depends on at least 4 sats. The better the chipset, the better the accuracy is.
So on your side the altitude is okay?

all chipsets besides the sirf III has about that error but garmin mobile xt corrects that issue and gives the correct value.

Related

Wrong Reading in Temperature

All application show wrong reading in temp it show abot 3.5 degree Celciuss and it's just not real..
Why >? how to fix that ?
The phone does not have a thermometer (Would be cool though) so you just need to specify the correct location but turning on GPS and Wireless network locations. If the correct location is set, there is nothing to do except for obtaining the temperatures from the server you determine your temperatures.
He is talking about CPU and battery temperature sensors. Mine doesn't work neither. Seems that only works in Fahrenheit.
I don't know how to fix.
Senate from my LG-P500h using XDA App
The fault is with the phone. When using certain battery apps, you're supposed to multiply the degrees by 10 to get the actual figure. So 3.5C = 35C
you do the same with 'v' except use 1000 so it'l be 4.000
and why exactly do it do that?, from what i've expirienced i figured it's a hardware problem, cuz i tried a lot of software modifications and got the same temperature readings.

[Q] GPS resolution at higher speeds

Hi,
today i used my SGS2 for comparing my cars instrument with gps-speed. While driving with cruise control i got 122,4 km/h (this is around 75mi/h). This value was very stable, after a minute or so there was 118,x for some seconds and then 122,4 again. No values in between . That looks very strange to me, anyone experienced the same effect? (using Lightning ROM 1.3, with both "GPS Test" and "Maps (-)")
...Alex
Speeds as low-res steps
I'm having the same experience with mine and this behavior appeared suddenly. It doesn't matter what speed I'm going in or what app I'm using for measuring speed, they all show speeds in clearly divided steps with low granularity. In Locus Pro, the speed chart shows clear steps in recorded speed (I cannot post screenshot yet due to rookie status)
Both SpeedView and Ulysse Speedometer have the same behavior, though the jumps differ a bit. If I remember correctly some of the steps in Ulysse was (in km/h): 76, 80, 83, 86, 90, 94. Nothing between these.
Browsing through the recorded tracks in Locus I can point to the date this behavior started, but I have no idea what I did that day, unfortunately.
yesterday i've used runtastic, it works like expected, while the other two mentioned earlier still fail...
...Alex
Hi,
This is also something I've noticed. Using GPS Test I've found the "resolution" of the reported speed from the GPS to be 1 m/s, which is equal to 3.6 km/h. This explains why some applications seem to have steps of 3-4 km/h on the speed rating.
Fixed somewhere between ke2 and kf3
I upgraded my phone to from ke2 to kf3 today and this issue seems to be fixed now. Otherwise, see this thread for a similar discussion.

[Q] GPS max altitude?

So I have been using my phone to record my flights, and I have to say that I am impressed with the capabilities of the Galaxy S2 GPS receiver, it manages to keep tracking during the complete flight!
One problem though, the altitude reported by the GPS "saturates" around 6000m (20000 feet), it doesn't go any higher.
As anyone experienced the same behavior?
Wasca
I guess the altitude is set using setGpsAltitude function in Camera.Parameters Class used by our cam.
http://developer.android.com/reference/android/hardware/Camera.Parameters.html
I don't understand your answer, I am not trying to take a photo!
What I am saying is that, when tracking my position during a flight, the altitude reported by applications like GPS test and GPS status never exceeds 6000m!
Hope I made my myself understood.
Wasca
Ok. I don't know why i thought of camera
Afaik, GPS system has an altitude limit of 60,000 feet. Don't know why is it limited to 20,000 feet in your case.
Since GPS system uses a rough spherical model of earth to calculate our position, it works best when we are on the ground. But altitude calculation is a different story, since there is no surface as a base of calculation.
Altitude is calculated by measuring the distance from the centre of the earth and the radius of surface model (spherical model of earth). This way, it calculates distance/altitude from the surface of the earth. This calculation is affected by factors such as density of earth crust (relates to gravity), distance from GPS satellites, (~12,500 miles) etc.
For safety reasons, and to try and make calculation more accurate, GPS system uses an error bias towards the direction of earth. This way, on higher altitudes, GPS will tell you, you're lower than your actual position. That is why it says you are at 6000 m even when your altitude is higher than that.
If you notice the accuracy reading of your location at higher altitudes, error in altitude is roughly 3 times that figure.
Hope this helps.
Thanks for this information, it was also new for me.
I wouldn't say it is an accuracy problem. In this case, measured altitude seems to be ok until the plane reach 20,000 feet, then the altitude just stops increasing.
I think that google has flown the nexus up to 10km altitude, and the GPS kept measuring altitude.
It looks to me it's a bug of the GPS of our phone.
Wasca
Hello,
I have recently used my galaxy SII on several flights. Initially I had a Locus Pro tracking running, switched the Galaxy to flight mode but forgot to turn the power off during start. I noticed this during the cruise at an altitude of >10000m. At this time the GPS was still on, but the track had stopped at 5487m at a speed of 832 km/h.
During the cruise the GPS seemed to be still working, 10 sats were received (could also watch the varying signal strength). However, position and altitude didn't update.
Now turned off the unit completely and starting it up. After some time a plausible (current) position was shown, however, with a wrong altitude (<6000m) This position froze again. I used several other GPS Apps, all with the same result.
My conclusion from this is:
The Sirf GPS chip seems to works well at this altitude and speed.
Either the Android 4.0.3 and/or the Samsung SW must have a setting to limit the use above 6000m .
I have contacted Samsung several times to get information about the maximum Height and Speed spec. of the Galaxy SII. The answer was always that they will contact the specialists - but never came back.
What I would like to do is to find this limiting setting, modify it to be able to track the flight with my Galaxy.
Any similar experiences?
Same problem with other smartphones?
Any suggestion?
Thanks
Dietrich

can i calibrate gps speed metter

hello friends i am using malaysk rom my device is rk3066 800*480
i have an issue with my gps speed for example my car speed is 60 kmh and mtcscreenclock gps speed shows 55 kmh .
is there any chance to calibrate gps speed ?
Thank you
derici84 said:
hello friends i am using malaysk rom my device is rk3066 800*480
i have an issue with my gps speed for example my car speed is 60 kmh and mtcscreenclock gps speed shows 55 kmh .
is there any chance to calibrate gps speed ?
Thank you
Click to expand...
Click to collapse
Are you sure your speedometer is correct?
Sent from my XT1575 using Tapatalk
derici84 said:
hello friends i am using malaysk rom my device is rk3066 800*480
i have an issue with my gps speed for example my car speed is 60 kmh and mtcscreenclock gps speed shows 55 kmh .
is there any chance to calibrate gps speed ?
Thank you
Click to expand...
Click to collapse
GPS is correct, your vehicle speed has a manufacturer built in margin to display lower than actual.
marchnz said:
GPS is correct, your vehicle speed has a manufacturer built in margin to display lower than actual.
Click to expand...
Click to collapse
My vehicle speed display is higher than gps speed not lower
Sent from my SM-G900FQ using XDA-Developers mobile app
derici84 said:
My vehicle speed display is higher than gps speed not lower
Sent from my SM-G900FQ using XDA-Developers mobile app
Click to expand...
Click to collapse
You're welcome.
Your GPS is accurate - the vehicle is inaccurate. That is correct, manufacturer builds in error so that vehicle speed displays a higher than actual vehicle speed, my understanding is this is standard practice
Think about why that might be. Also, have you thought about validating GPS/speed with your smart phone? Also note that vehicle modifications such as diff, gearbox, rim and wheel size can impact final drive thus speedo.

Altitude error - stratos

I am using STRATOSfied rel 14 | 2.0.32.0 and I'm having the same problem as I had with the original ROM. In long distance races, a certain km altitude has an error. The marking is lost, that is, I am climbing and the marking is as if I had descended and with that even after re-marking right the difference between altitude gets very large.
GiovaniM said:
I am using STRATOSfied rel 14 | 2.0.32.0 and I'm having the same problem as I had with the original ROM. In long distance races, a certain km altitude has an error. The marking is lost, that is, I am climbing and the marking is as if I had descended and with that even after re-marking right the difference between altitude gets very large.
Click to expand...
Click to collapse
Stratos has bad reputation for resulting altitude reporting. Turning on 3D Data in activity setting and syncing to the phone to refresh AGPS might help but I personally don't bother with it anymore. In Strava you can correct altitude after upload or fix it with DEM data on your gpx file before upload (e.g. gpsvisualiser.com).
EDIT: You might try to check following things https://forum.xda-developers.com/showpost.php?p=77315879&postcount=6
I just came back from my holidays. Every morning, I was riding my bicycle and a large part of the course was at sea level. And, every day, I got constantly different altitude readings on my Stratos: from -60 to -10 meters, while at sea level. I also use a Garmin Edge 705 on my bike, which I noticed that it corrects to altitude reading. I suspect that Stratos is just calculating the altitude only using the barometric pressure sensor and not taking into account the GPS data.
keneva said:
I just came back from my holidays. Every morning, I was riding my bicycle and a large part of the course was at sea level. And, every day, I got constantly different altitude readings on my Stratos: from -60 to -10 meters, while at sea level. I also use a Garmin Edge 705 on my bike, which I noticed that it corrects to altitude reading. I suspect that Stratos is just calculating the altitude only using the barometric pressure sensor and not taking into account the GPS data.
Click to expand...
Click to collapse
Actually it depends on the activity: some will use GPS and some will use the barometer. And as you cannot calibrate barometer so far, don't expect a precision lower than -50m/+50m.

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