Lost GPS signal

[Martyray]

This might be a silly question however, I thought I would just ask as I don't understand why this happened to me during my flight today......
I was flying about 45 meters altitude and had 17 satellite connections and a strong signal...
Then all of a sudden I lost all satellite connections and received a verbal warning that the return home function would not function with out satellite signal.....
I temporarily lost control of my drone ,all though I will admit i may have just lost the orientation of the craft and thus was not putting control correct inputs
I managed to get it to the ground and subsequent Flights I noted that the satellite signal was intermittent at best...
Drone also seemed to gain altitude slowly with no input from me. This continue to happen for about 15 minutes Before It regain altitude stability
After the flight , on the return home I noticed a mobile phone tower of a 1/2 a kilometre from my flight location would this have affected the GPS signal?
Unfortunately the flight data during this event is not very reliable as the tracking of the drone was obviously lost during the failure of GPS signal.

I would greatly appreciate anybody's advice

 

[Dakarenduro]

Perhaps a faulty drone? Which model and how many flights do you have on it?

But if you post the dat files I am sure one of the gurus on here would parse the file for you and point you in the right direction.

 

[Meta4]

After the flight , on the return home I noticed a mobile phone tower of a 1/2 a kilometre from my flight location would this have affected the GPS signal?

Not even a little bit.

 

[Johnmcl7]

Unfortunately the flight data during this event is not very reliable as the tracking of the drone was obviously lost during the failure of GPS signal.

As long as the controller remained connected to the drone it will have been logging data and this is by far the most useful way for anyone to give advice on what happened. This topic explains how to retrieve them:

Mavic Flight Log Retrieval and Analysis Guide

With the introduction of the Mavic Mini there has been a noticeable uptick in the number of posts requesting help with lost or crashed aircraft. While there is plenty of help and advice available on this forum, and detailed guidance and options on several other websites, I thought that perhaps a...

mavicpilots.com

 

[steve_lyt]

if it happens in an area you normally get good control and gps, it may be atmospheric interference, I had a similar problem , but I lost my drone. if your controller speaks to you make sure it has said home point recorded

 

[sar104]

if it happens in an area you normally get good control and gps, it may be atmospheric interference, I had a similar problem , but I lost my drone. if your controller speaks to you make sure it has said home point recorded

Atmospheric conditions have a negligible effect on GPS signals - it's not going to be that.

 

[Martyray]

I'll try to Retrieve the flight log information and post it.

 

[Martyray]

if it happens in an area you normally get good control and gps, it may be atmospheric interference, I had a similar problem , but I lost my drone. if your controller speaks to you make sure it has said home point recorded

At takeoff, I received a verbal " home point set" from contract...
When I lost GPS signal I received " GPS signal lost. Return home will not function while no GPS signal" or words to that effect

 

[Martyray]

ok.
i think this is correct.
please forgive me if its not as im only new at this.
once again , i greatly appreciate your time and expertise.
this should be the link to the flight data:

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

 

[Jonathonmp]

Atmospheric conditions due to the sun. Here in the states we should be well past the awful solar winds and solar storms but that could be farther than the truth. A few years ago it was sunspot 1158 I believe that was wrecking havoc on vhf and hf band conditions. I too have noticed a severely degraded gps signal than all of a sudden will climb back to almost normal.
This is to be expected given the solar activity. Our ham radio bands both vhf and hf have been the worst since even the old timers as they call themselves can remember.

 

[Meta4]

Atmospheric conditions due to the sun. Here in the states we should be well past the awful solar winds and solar storms but that could be farther than the truth. A few years ago it was sunspot 1158 I believe that was wrecking havoc on vhf and hf band conditions. I too have noticed a severely degraded gps signal than all of a sudden will climb back to almost normal.
This is to be expected given the solar activity. Our ham radio bands both vhf and hf have been the worst since even the old timers as they call themselves can remember.

There are millions of GPS users around the world so what you are suggesting would certainly be noticed ... if it happened.
But it just doesn't happen.

 

[Meta4]

Then all of a sudden I lost all satellite connections and received a verbal warning that the return home function would not function with out satellite signal.....
...
Unfortunately the flight data during this event is not very reliable as the tracking of the drone was obviously lost during the failure of GPS signal.

Your flight data shows that loss of GPS signal was not your problem at all.
You had proper GPS signal the whole time.
Your issue was a yaw error situation which made the flight controller ignore GPS data.
That's usually caused by launching from a location with magnetic interference .
Do you remember what direction your Mavic was pointing at launch time?

btw .. The GPS tracking in the flight data is accurate.

There's something odd in the data that makes it look like the drone thought it was partly in RTH for much of the flight.
I've not seen that before and can't tell what caused that or if that had any effect.

 

[Jonathonmp]

There are millions of GPS users around the world so what you are suggesting would certainly be noticed ... if it happened.
But it just doesn't happen.

It does in fact happen. I'm chief RF engineer for many television stations around the country so my background with RF and things mostly in the HF portion is very extensive. Many stations ask that there be a message put out to all satellite subscribers at the uplink facility so people understand. I am not going to get into why it affects certain regions and hemispheres at a time but for you to say "It just doesn't happen" is highly inaccurate and quite frankly appalling. I'm a sense your mocking my profession and knowledge of this stuff.

 

[Jonathonmp]

Oh and one other item. You may not notice it in your area because it may not be the time of year or season when solar winds are as strong but also these sun outages and interruptions happen fairly quickly. We had a local channel to Directv and to dish network uplink facility this past Monday lose all locals for those customers for about 1 minute and 12 seconds. Sometimes they are longer around 5 minutes.
The only type of satellite systems or the only type of satellites affected by this at least for a few moments are geostationary satellites.

 

[Meta4]

It does in fact happen. I'm chief RF engineer for many television stations around the country so my background with RF and things mostly in the HF portion is very extensive. Many stations ask that there be a message put out to all satellite subscribers at the uplink facility so people understand. I am not going to get into why it affects certain regions and hemispheres at a time but for you to say "It just doesn't happen" is highly inaccurate and quite frankly appalling. I'm a sense your mocking my profession and knowledge of this stuff.

We had a local channel to Directv and to dish network uplink facility this past Monday lose all locals for those customers for about 1 minute and 12 seconds. Sometimes they are longer around 5 minutes.

That satellite TV transmissions may be affected is interesting but the topic of this thread is GPS.
Can you show where GPS has been affected the way you describe ?

 

[sar104]

This is a strange one. There was a large error in the IMU velocity solution at the end of the flight which caused the FC to switch to ATTI mode. The cause is not clear at all.



This will require the mobile device DAT file (or aircraft DAT if the mobile device file isn't available) - filename ending FLY054.DAT.

 

[sar104]

Oh and one other item. You may not notice it in your area because it may not be the time of year or season when solar winds are as strong but also these sun outages and interruptions happen fairly quickly. We had a local channel to Directv and to dish network uplink facility this past Monday lose all locals for those customers for about 1 minute and 12 seconds. Sometimes they are longer around 5 minutes.
The only type of satellite systems or the only type of satellites affected by this at least for a few moments are geostationary satellites.

Then we are fortunate that GPS satellites are not geostationary. In any case, geomagnetic conditions have a negligible effect on GNSS signal reception for consumer-grade receivers except, very occasionally, at very high latitudes and very strong solar ejections.

 

[Jonathonmp]

That satellite TV transmissions may be affected is interesting but the topic of this thread is GPS.
Can you show where GPS has been affected the way you describe ?

Probing Question: What do sunspots have to do with GPS reception? | Penn State University

I skimmed the article really quick and saw that they outline it very nicely.

 

[Martyray]

Your flight data shows that loss of GPS signal was not your problem at all.
You had proper GPS signal the whole time.
Your issue was a yaw error situation which made the flight controller ignore GPS data.
That's usually caused by launching from a location with magnetic interference .
Do you remember what direction your Mavic was pointing at launch time?

btw .. The GPS tracking in the flight data is accurate.

There's something odd in the data that makes it look like the drone thought it was partly in RTH for much of the flight.
I've not seen that before and can't tell what caused that or if that had any effect.

Thankyou for reviewing the data.
It's situation has really rocked my confidence in both my ability and the crafts.
There is a mobile phone tower about 400 mtrs north of the location. Would this have had an impact on the flight?
At time of launch, the craft was facing east

 

[Meta4]

There is a mobile phone tower about 400 mtrs north of the location. Would this have had an impact on the flight?

Again .. the mobile phone tower had zero impact on your flight
The source of the problem was probably closer than a metre away from your Mavic at launch time.