Enable GPS mid flight

[sdharris]

I have read a couple of threads about this but all date back to middle of last year prior to the November firmware so wondered if anyone has had the same experience.

I took my Typhoon H and Mavic to a place named Cheddar Gorge earlier this week, this featured on the Grand Tour recently and was described as the Grand Canyon of the UK, in jest obviously.

At its highest point its about 500 feet up from the road below and understandably GPS signal is not great on the floor at that point. However the Mavic got GPS lock quickly and was fine. The Typhoon however (bless it) got 9 satellites but not enough to get a fix and would not start motors. So I thought, OK will disable GPS to get it in the air, gain altitude get a GPS fix and then use that for more stable flight before returning to the take off location hopefully with GPS but if not will fly without.

I didn't realise this but it seems if you take off with GPS disabled you cannot switch it on mid flight, which came as a surprise. I have read threads about issues whereby regaining GPS has caused the Typhoon H to suddenly fly back to its last GPS point but surely Yuneec factor that in and ensure the transition from non GPS to GPS is smooth.

It was a shame and would have liked the stability of the Typhoon H for a location like this but the Mavic did OK - Instagram photo by Steve Harris • Jan 26, 2017 at 1:22pm UTC

Has anyone managed to enable GPS mid flight or get the motors to start without GPS lock but with it enabled?

 

[Steve Carr]

Actually, I was not aware that it couldn't be turned on if you launch with it off. However, one issue I can see in this situation is with the controller. If the H didn't have sat lock then it's unlikely the controller did either. The H needs to know the position of the controller to calculate distance and direction back to the controller which is the home point.

 

[PatR]

Something to consider, and something I don't have the answer to, is the ability of the H to capture an acceptable home fix while in flight if GPS had been disabled prior to launch. Lacking that ability I could understand where such a condition might generate a system conflict that would prevent enabling GPS with the aircraft in flight and motion.

If such was the case I would think a change in coding might permit positional acquisition in flight while at the same time denying the ability to use the RTH function. However, such a condition would be far beyond the comprehension of a great many users that fail to read instructions, warnings, or bother to learn anything about the system beyond how to push the sticks around. In effect Yuneec would be damned if they did and damned if they didn't.

 

[sdharris]

Actually, I was not aware that it couldn't be turned on if you launch with it off. However, one issue I can see in this situation is with the controller. If the H didn't have sat lock then it's unlikely the controller did either. The H needs to know the position of the controller to calculate distance and direction back to the controller which is the home point.

Oh yeah its fraught with danger especially on signal loss but I was surprised with the behaviour, perhaps I am used to DJI products and updating a home point.

In this situation I would have liked to have gained height and used GPS for stable hover accepting that a RTH would not be possible unless the home point could be set.

I am wondering whether GPS can be toggled off in flight, then back on. I used to do this with DJI products to let it 'drift' with the breeze.

I am going to have to find a big field and experiment more.

 

[Graham]

I think you may have been asking a lot from any GPS system. I don't remember much in the way of open sky from the centre of the gorge.
Yes, the Typhoon's GPS can be switched on and off in flight. Some say turning it off reduces twitchiness, but for me its all about the SPEED!

 

[gwhuntoon]

Uwe's video demonstrates this

 

[PatR]

Thinking about this a little more, I can see how someone wanting to take off in a NFZ might turn the GPS off prior to flight to get into the air and end up a little disappointed when it would not turn on once in the air if it was still inside the NFZ.

 

[ArnhemAnt]

In the testing I have done, I experienced exactly the same behaviours in flight as shown in the video above from Uwe as posted by gwhuntoon. In essence, you're not actually turning the GPS off, but merely disabling its assistance during flight. Regardless of whether the GPS is turned 'off' or 'on' it is still working and gathering/updating data.

 

[PatR]

That has to be else the speed display would not function. There's no pitot equipment on the H.


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[Jussaguy]

Actually, I was not aware that it couldn't be turned on if you launch with it off. However, one issue I can see in this situation is with the controller. If the H didn't have sat lock then it's unlikely the controller did either. The H needs to know the position of the controller to calculate distance and direction back to the controller which is the home point.

The sats that show on the tX are indeed the locks of GPS from bird to craft and shouldn't change unless the bird gets worse reception but when you take off it is showing you how many sats are locked from the bird and the tx together and you can never get better than this, only worse so you are correct.

If it's not getting good connection on the ground, it won't in the air. One thing I have not found flying with my H is a lack of ability to lock on to sats.

Great shot on that instagram photo btw!

 

[Steve Carr]

The GPS can only be disabled on the H. The GPS in the controller cannot be turned off. As @ArnhemAnt points out, when you turn it off on the H it is only telling the Flight Controller to disregard GPS. The GPS is still on and functioning. There are two readings on the ST16 for the number of Sats acquired. One for the H and one for the ST16. They work independently so if you move while flying, the H knows the ST16 has moved to a new location. That means the home point is dynamic. It is always the location of the ST16. You cannot set a home point.

 

[dxer]

Hey guys

As you are talking about GPS, can you answer me on this.
What does actually means when on ST16 -(on the left where telemetry is) under GPS is green Ready ? I mean, when I am inside and there are zero satellites, it is green Ready and I obviously can't use GPS inside ? I am asking this because I am not sure how can I actually fly inside . Do I need to disable GPS or ?
I don't want copter to became unpredictable inside because GPS is not working.

 

[ArnhemAnt]

^^ Not sure why you would want to fly a frame such as the H inside, unless you have a large open undercover area, or a very big house/shed.
Regardless, from my understanding, if the word 'Ready' is lit green, then you should be able to arm and take off.
Not having GPS or. more to the point, a 'fix' with the satellites will not necessarily mean that your H is going to be 'unpredictable', it just means that you are the one flying it, not the GPS/satellites holding you if you let go of the sticks.
Having the GPS enabled gives you access to features such as 'watch', 'follow', 'CCC' 'POI', 'journey' etc. Not really things I would want to be trying if I was indoors anyway.

 

[dxer]

But this green Ready is under GPS and in the same time showing zero satellites. This is confusing. How could GPS be Ready if no satellites.
For about flying inside, this is just theoretical question to understand what is happening in possible inside flying.

 

[Atomic08]

Asking just to clarify something else....
While watching the video I noticed that the H does not seam to change altitude when the GPS is turned off...
Is the Barometer still turned on and does it maintain altitude ?

 

[Rayray]

The sats that show on the tX are indeed the locks of GPS from bird to craft and shouldn't change unless the bird gets worse reception but when you take off it is showing you how many sats are locked from the bird and the tx together and you can never get better than this, only worse so you are correct.

I'm thinking you may want to study more about this.

 

[Peter Bosmans]

The H won't take off in a NFZ, not even with GPS turned off.

 

[Jussaguy]

I'm thinking you may want to study more about this.

It's wrong? I can take it. What?

 

[PatR]

Asking just to clarify something else....
While watching the video I noticed that the H does not seam to change altitude when the GPS is turned off...
Is the Barometer still turned on and does it maintain altitude ?

The barometer is the primary control function for altitude all the time. When functioning, GPS is secondary.


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[dxer]

Not sure how accurate exactly altitude measures should be on the H but for sure it is not accurate. In flight fails at least for several meters and on landing is couple of meters off too. So we have barometer, GPS and IPS.....I think we should expect more accuracy.