Altitude incorrect

[erikgraham]

I took SOLO out for a couple of batteries today. Didn't have much time to do detailed tests but the bottom line is that my auto altitude control is all over the page. Everything was done at or just above walking speed so there's no effect from AOA.

To begin with I hovered at about 5-6'. SOLO descended, uncommanded to about 18". The app still indicated 6'. The app seemed to initially register pretty accurate altitude but SOLO'S altitude would change, almost always it descended and the app reported altitude never changed.

The site WAS modestly unlevel but the odd thing seemed that if I flew toward rising terrain SOLO maintained it's altitude relative to home and appeared to be descending, as would be appropriate. As I flew away toward (definitely) descending terrain as checked by sighting down a level, it DID descend and at about 300' from home it was down to about 3' agl. I walked out to it then flew it back to home walking with it. The entire time the app indicated 10' altitude. By the time I got back to home SOLO was at 6', or head high, app showed 10'.

When I just took off and hovered at any altitude of 10' or below it's altitude would vary by as much as 5-6'.

Under normal flight conditions this wouldn't make any difference, and likely wouldn't be noticed, but I'm flying in some tight areas near trees and obstructions using fpv and I find this disconcerting. I think I'll call 3dr and see what they say.

Ok. To me this actually sounds like its operating at or close to within spec. I think 3DR will tell you that the drone will keep position within a 1 meter bubble - let's see. Post back when you get a reply.

 

[SPP]

Hi All,

Hello Hello....

I am new here and is trying to learn of the SOLO 101, before I fly it.
So altitude measurement is something very important for me to learn

I started with DJI Phantom 1 and stop there for like 2 years, so I am more into MANUAL mode for all controls and totally visual line of sight flying. With SOLO able to do all AUTO for Smart Shots, me must learn of its data gathering methods and its limitation. I am in Indonesia and we do not get the luxury of WAAS or any SBAS correction, so need to be extra careful when USA GPS civilan signal is the only positioning data I have.

Reading thru these posts, I manage to gather some data on barometric pressure for USA. Attached is one NOAA station in Providence, 15 minutes period.
ERDDAP - NOS CO-OPS Meteorological Data, Barometric Pressure, 6-Minute - Make A Graph

From 1016.5 to 1015.7 millibars in just 15 minutes. That is 21.8 feet or 6.7 meters difference. 0.8 millibars difference. Logged by NOAA on 23rd Jan 2016 10:10AM to 10:25AM
http://www.srh.noaa.gov/epz/?n=wxcalc_pressurealtitude
Calculator below. 1013.25 is 0 meter/feet, standard reference.
Pressure Altitude Calculator

Something unique I found when I did a search on the barometer pressure differences in USA cities. This one shows which cities has highest difference and what months they are.
Avoiding Migraines Resulting from Changes in Barometric Pressure

U.S. Cities Barometric Pressure Variation, Full List

I hope to learn more here and hope to contribute some too.
NOTE : Without this forum, I would have got stuck permanently trying to initialize the Solo to the Controller, as I done it out of the box brand new and with gimbal installed immediately...LOL. Done it without gimbal and then with gimbal, all good. Thanks guys.

SPP

 

[Maddog]

Hi All,

Hello Hello....

I am new here and is trying to learn of the SOLO 101, before I fly it.
So altitude measurement is something very important for me to learn

I started with DJI Phantom 1 and stop there for like 2 years, so I am more into MANUAL mode for all controls and totally visual line of sight flying. With SOLO able to do all AUTO for Smart Shots, me must learn of its data gathering methods and its limitation. I am in Indonesia and we do not get the luxury of WAAS or any SBAS correction, so need to be extra careful when USA GPS civilan signal is the only positioning data I have.

Reading thru these posts, I manage to gather some data on barometric pressure for USA. Attached is one NOAA station in Providence, 15 minutes period.
ERDDAP - NOS CO-OPS Meteorological Data, Barometric Pressure, 6-Minute - Make A Graph

From 1016.5 to 1015.7 millibars in just 15 minutes. That is 21.8 feet or 6.7 meters difference. 0.8 millibars difference. Logged by NOAA on 23rd Jan 2016 10:10AM to 10:25AM
Calculator below. 1013.25 is 0 meter/feet, standard reference.
Pressure Altitude Calculator

Something unique I found when I did a search on the barometer pressure differences in USA cities. This one shows which cities has highest difference and what months they are.
Avoiding Migraines Resulting from Changes in Barometric Pressure

U.S. Cities Barometric Pressure Variation, Full List

I hope to learn more here and hope to contribute some too.
NOTE : Without this forum, I would have got stuck permanently trying to initialize the Solo to the Controller, as I done it out of the box brand new and with gimbal installed immediately...LOL. Done it without gimbal and then with gimbal, all good. Thanks guys.

SPP

Welcome to the forum!

If you're keeping Solo in sight I don't think you need to worry to much about the altitude variance.

 

[SPP]

Welcome to the forum!

If you're keeping Solo in sight I don't think you need to worry to much about the altitude variance.

Agree....
I want to try the Follow Me, so me must know the do and don't when the ground itself varies in height.

Thanks MD.
.

 

[Jubalr]

Solo doesn't (can't) adjust altitude in Follow mode. There is no altitude reference from the device you are following. You will have to do that manually. Best advise is start at an altitude that is high enough to clear on your route.

 

[Stealth]

Have you noticed Solo's Altitude when it lands.
Mine varies a lot from 1-2 meters to 8-9 meters (always a positive number, meaning that when Solo lands it things that it is still in the air). It would be a problem if Solo hits RTH (today it almost happened to me as Controller's battery hit 5% warning) and could not calculate altitude correctly.
Another problem that I encountered is when making Orbit mode around my car - Solo could not maintain altitude and almost touched ground.
Plz post your Solo's landing altitudes.

 

[David Boulanger]

Stealth, Are you allowing the Solo to acclimate to the temperature outside when you fly it. This will effect the barometer. Also the landing detector in the firmware can handle landing even if it thinks its still a few meters up in the air.
Regards,
David R. Boulanger

 

[Stealth]

Stealth, Are you allowing the Solo to acclimate to the temperature outside when you fly it. This will effect the barometer. Also the landing detector in the firmware can handle landing even if it thinks its still a few meters up in the air.
Regards,
David R. Boulanger

Thanks, David!
I take out Solo of the box and put GoPro and then Fly. So Solo has around 5 min. to acclimate to the temperature. Though when I fly a second pack of batteries Solo has been in the open for more than 30 min. (2 packs x 13 min. + time to change the battery + time to load GoPro and prepare for takeoff). Usually after the second flight the inaccuracy is lower than after the first flight.
How long does it take for Solo to acclimatize?
I have some previous experience in fixed wing FPV. I fly a Bixler 2 with ArkBird AP. Never got more than 1 m. altitude inaccuracy. Never let my Bixler 2 acclimatize before each flight.

 

[Jubalr]

Have you noticed Solo's Altitude when it lands.
Mine varies a lot from 1-2 meters to 8-9 meters (always a positive number, meaning that when Solo lands it things that it is still in the air). It would be a problem if Solo hits RTH (today it almost happened to me as Controller's battery hit 5% warning) and could not calculate altitude correctly.

The barometer variance will not effect RTH other than clearing an obstacle in it's path, which hopefully you have set your RTH more than 10m over the highest obstacle in the area you are flying. When Solo is landing it only uses the Barometer to slow the descent some. Even if the landing was off horizontally and somehow descended down a 100' hole, it would continue to descend at the same rate until it determined it had landed by no longer descending.

 

[David Boulanger]

The barometer variance will not effect RTH other than clearing an obstacle in it's path, which hopefully you have set your RTH more than 10m over the highest obstacle in the area you are flying. When Solo is landing it only uses the Barometer to slow the descent some. Even if the landing was off horizontally and somehow descended down a 100' hole, it would continue to descend at the same rate until it determined it had landed by no longer descending.

Yup, that's about right
Regards,
David R. Boulanger

 

[Stealth]

The barometer variance will not effect RTH other than clearing an obstacle in it's path, which hopefully you have set your RTH more than 10m over the highest obstacle in the area you are flying. When Solo is landing it only uses the Barometer to slow the descent some. Even if the landing was off horizontally and somehow descended down a 100' hole, it would continue to descend at the same rate until it determined it had landed by no longer descending.

Thanks!
But it still an issue for me.
Talked to Gio (3DR Tech Support) and filed a ticket.
Will let you know the outcome next week.

 

[Stealth]

I flew my Solo today. At the end of the second flight, the battery got 15% and Solo hit RTH just when I was approaching for landing at no more than 10 m. altitude. It accented a little and just as I was thinking that Solo will not have enough battery to climb to 60 m. As I have set it (I forgot the cone thing) and land back, Solo began do decend and when it reached around 2 m. lowered its decending speed and landed softly at 5% battery. After landing it showed 5 m. altitude. May the altitude reading not to be shown correctly, but Solo to know the right altitude?

 

[Jubalr]

I flew my Solo today. At the end of the second flight, the battery got 15% and Solo hit RTH just when I was approaching for landing at no more than 10 m. altitude. It accented a little and just as I was thinking that Solo will not have enough battery to climb to 60 m. As I have set it (I forgot the cone thing) and land back, Solo began do decend and when it reached around 2 m. lowered its decending speed and landed softly at 5% battery. After landing it showed 5 m. altitude. May the altitude reading not to be shown correctly, but Solo to know the right altitude?

As stated above, the barometer does not effect the auto landing the way you are thinking. It will continue to descend slowly until it has landed and stopped descending, regardless of what the barometer is saying. It doesn't just look for '0' then quit flying. when it no longer detects it is descending, it considers itself 'landed'.

 

[Stealth]

As stated above, the barometer does not effect the auto landing the way you are thinking. It will continue to descend slowly until it has landed and stopped descending, regardless of what the barometer is saying. It doesn't just look for '0' then quit flying. when it no longer detects it is descending, it considers itself 'landed'.

Thanks for the feedback!
I wonder what is the altitude on which Solo slows the descend rate? Sometimes My Solo shows 10 m. Altitude when it has already landed. Having said that next time Solo may not lower descend rate if it is set at 8 m. e.g.!
What is the altitude that your Solo shows when it has landed?

 

[Jubalr]

Thanks for the feedback!
I wonder what is the altitude on which Solo slows the descend rate? Sometimes My Solo shows 10 m. Altitude when it has already landed. Having said that next time Solo may not lower descend rate if it is set at 8 m. e.g.!
What is the altitude that your Solo shows when it has landed?

Never paid any attention to it, to be honest. About the only time I will glance at is is for a general reference at higher altitudes over 100'. Unless I am doing a smart shot, survey, etc. or needing to hover in one spot for adjustments, I am in manual mode. I also fly VLOS, so as long as I see it, I'm not worried about the altitude Solo thinks it is. And if I can't see it briefly, I'm looking at the live view. And I land and take off in manual as well. And that's one of the reasons in a year and a half of flying Solo I have never busted a prop or had any kind of hard landing. I reduce the reliance on accuracy/reliability of electronics when practical. Just my opinion, YMMV..