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Angle flight mode incorporates GPS, barometric and other sensors to maintain stable position in flight .
Every aircraft that takes off from an airport sets it’s altimeter to the elevation of the airport it’s taking off from , then some fairly complicated math , including barometric pressure ,and tower to tower updates keep the pilot flying true.
Good luck flying without a GPS system in a rapidly changing weather environment . Before GPS satellites, pilots would just fly into the side of a mountain at night during foul weather because of an incorrect altimeter reading . Both GPS and barometer are critical to successful flight (.A squared plus B squared equals C squared ) if you fly in manual mode you are using the barometer.
 
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Steve Carr

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It is my understanding these aircraft do not use GPS to derive altitude but rather a combination of the barometer and the accelerometers. The barometer is reset to zero when you start the motors.
 
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It is my understanding these aircraft do not use GPS to derive altitude but rather a combination of the barometer and the accelerometers. The barometer is reset to zero when you start the motors.
That's true. Altitude is the least accurate of GPS positioning and can vary by 50-150' and would be of little use in consumer MRs.
 
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Every time a new flight controller is released, the barometer is for sure one of the pieces that has been updated, each time better. To the extent that the "professional" controllers incorporate redundancy of this device and have algorithms that compare and optimize the results of the values that come out of them.

In fact, the recommendations for the installation of these plates incorporate two things that many people do not pay attention to but that are very important, do not give them the wind or the sun directly, so that there are no fluctuations of the values by unnecessary changes in the pressure they measure.
 
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It is my understanding these aircraft do not use GPS to derive altitude but rather a combination of the barometer and the accelerometers. The barometer is reset to zero when you start the motors.
YUNEEC SUPPORT.com replied, angle mode uses GPS & manual mode uses the barometer.
 
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I think Yuneec Support must be wrong, both use barometer.
GPS receivers return altitude data, but this is inaccurate. The error margin depends on the satellite constellation geometry and whether or not you have both on.
A barometer is a much more accurate and fast device to extract altitude,
 
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That's true. Altitude is the least accurate of GPS positioning and can vary by 50-150' and would be of little use in consumer MRs.
Altitude is a relative measurement of AGL & where you are standing while you hold the ST 16 S controller hence the triangulation factor using GPS systems. If one is walking around on earth with a GPS navigation tool there is no AGL triangulation with your aircraft, because you do not have an aircraft , and therefore without the triangulation the GPS systems can be in Inaccurate .
 

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FWIW, I have flown my H+ from a starting point on the side of a large/steep slopes. Height of the slopes/cliffs range from 80 to 200 feet. Not sure if the 520 does it differently, but the H+ always shows height over starting point. I know this because when I take off and fly out over the lower elevations the altitude displayed does not change. Seems if GPS were involved it would "know" the ground was farther below than when I launched.
 
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GPS altitude is recorded but not used for any type of feed in to the control system. It is far too inaccurate to be of use in that way. Typically 50-150' in error variance from actual.
 
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Steve Carr

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YUNEEC SUPPORT.com replied, angle mode uses GPS & manual mode uses the barometer.
Only the people who wrote the code would know for certain how the number is derived. The people who wrote the code don't share much even with the support people. So, in this case, support is guessing and they missed the mark. There is zero evidence GPS has ever been used for altitude on any Yuneec product. There is plenty of evidence to demonstrate that the accelerometers and the barometer are used to calculate the number.
 

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Only the people who wrote the code would know for certain how the number is derived. The people who wrote the code don't share much even with the support people. So, in this case, support is guessing and they missed the mark. There is zero evidence GPS has ever been used for altitude on any Yuneec product. There is plenty of evidence to demonstrate that the accelerometers and the barometer are used to calculate the number.

I would go beyond that, in this case the one who answered that doesn't know the basics of how a drone works, or simply hasn't understood the question. For the altitude the GPS is only used to take an ASL reference and then the barometer that is set to 0 in the home indicates the altitude from the home.

Another thing is that you can change how you want to see the height, or ASL (initial GPS height + precise barometer height) or relative to the home which is the most common.

I think he is confused, so he says, with the flight modes, where in the angle mode drift and position corrections occur with the GPS and not in manual mode. That's why in Angle mode, despite a strong wind is very stable with wind (position corrections are made) and in manual mode as these corrections do not exist, the drone is dragged by the wind. This has nothing to do with height :rolleyes:
 
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FWIW, I have flown my H+ from a starting point on the side of a large/steep slopes. Height of the slopes/cliffs range from 80 to 200 feet. Not sure if the 520 does it differently, but the H+ always shows height over starting point. I know this because when I take off and fly out over the lower elevations the altitude displayed does not change. Seems if GPS were involved it would "know" the ground was farther below than when I launched.
Have you ever seen your telemetry read a negative elevation ?
 
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Have you ever seen your telemetry read a negative elevation ?
If you were standing on 1000 foot tall building and you take off and fly 100 feet above, your telemetry will read 100 feet of elevation if you’re a maned aircraft pilot and you take off from the top of the building you need to set your altimeter to 1000 feet before you take off so your barometer will read 1100 feet . In GPS mode it is a triangulation between satellite or satellites ,controller and aircraft . In manual mode the barometer is always set at zero @take off just like an aircraft pilot of a maned aircraft would do and then from there on in manual mode your barometer will reflect the difference of height from takeoff.
 

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If you were standing on 1000 foot tall building and you take off and fly 100 feet above, your telemetry will read 100 feet of elevation if you’re a maned aircraft pilot and you take off from the top of the building you need to set your altimeter to 1000 feet before you take off so your barometer will read 1100 feet . In GPS mode it is a triangulation between satellite or satellites ,controller and aircraft . In manual mode the barometer is always set at zero @take off just like an aircraft pilot of a maned aircraft would do and then from there on in manual mode your barometer will reflect the difference of height from takeoff.

Comrade, we're talking about drones, helicopters or manned planes or what we're talking about. You don't have to establish any height, in manned vehicles it is because the height measurement is precise, depending on where in the world you are and at what height you add that value. But in drones you don't do anything like that. Simply, the good height is the one that determines the barometer starting from the home. In a manned vehicle you can travel a lot of distance and there is the difference.

Of course you can see negative height, following your example, take off from the roof of a skyscraper and descend into the street. The home, relative height 0 is on the roof, in negative the height of the building.

Something simpler and more common with drones, you take off anywhere and make a descent into a valley from the top. It is always relative to where you have taken off so in this case it will also show you negative values. In case you do an RTL you will ascend to the height you have determined as RTL. In other words, you don't determine that it goes up 40m, you determine that it goes up the drone up to 40m from the home. It would raise all the negative plus the 40 meters that you have determined as RTL height.

I'm sorry if I haven't understood you well, me and the English :rolleyes:
 
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Why GPS is NOT used in any modern drone manufacturer's FC for any type of positioning. It is only recorded as a matter of reference:

Generally, GPS Altitude error is specified to be 1.5 x Horizontal error specification. This means that the user of standard consumer GPS receivers should consider +/-23meters (75ft) with a DOP of 1 for 95% confidence. Altitude error is always considerably worse than the horizontal (position error). Much of this is a matter of geometry. If we (simplistically) consider just four satellites, the "optimum" configuration for best overall accuracy is having the four SVs at 40 to 55 degrees above the horizon and one (for instance) in each general direction N, E, W, and S. (Note: You will get a very BAD DOP if the SVs are at the exact same elevation. Luckily, this is a rare occurrence.) The similar "best" arrangement for vertical position is with one SV overhead and the others at the horizon and 120 degrees in azimuth apart. Obviously, this arrangement is very poor from a signal standpoint. As a result, of this geometry the calculated solution for altitude is not as accurate as it is for horizontal position. Almost any calibrated altimeter will be more stable at reading altitude than a GPS.

GPS altitude measures the users' distance from the center of the SVs orbits. These measurements are referenced to geodetic altitude or ellipsoidal altitude in some GPS equipment. Garmin and most equipment manufacturers utilize a mathematical model in the GPS software which roughly approximates the geodetic model of the earth and reference altitude to this model. As with any model, there will be errors as the earth is not a simple mathematical shape to represent. What this means is that if you are walking on the seashore, and see your altitude as -15 meters, you should not be concerned. First, the geodetic model of the earth can have much more than this amount of error at any specific point and Second, you have the GPS error itself to add in. As a result of this combined error, I am not surprised to be at the seashore and see -40 meter errors in some spots.


Given that the average drone spends most of it flight time at 100m or less, would it make since to use altitude with an error rate of 40m or more?
 
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Comrade, we're talking about drones, helicopters or manned planes or what we're talking about. You don't have to establish any height, in manned vehicles it is because the height measurement is precise, depending on where in the world you are and at what height you add that value. But in drones you don't do anything like that. Simply, the good height is the one that determines the barometer starting from the home. In a manned vehicle you can travel a lot of distance and there is the difference.

Of course you can see negative height, following your example, take off from the roof of a skyscraper and descend into the street. The home, relative height 0 is on the roof, in negative the height of the building.

Something simpler and more common with drones, you take off anywhere and make a descent into a valley from the top. It is always relative to where you have taken off so in this case it will also show you negative values. In case you do an RTL you will ascend to the height you have determined as RTL. In other words, you don't determine that it goes up 40m, you determine that it goes up the drone up to 40m from the home. It would raise all the negative plus the 40 meters that you have determined as RTL height.

I'm sorry if I haven't understood you well, me and the English :rolleyes:
Thank you for the clarification ,I was just repeating what I was told by YUNEEC support, and that in angle mode GPS was used to determine altitude.
 

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Thank you for the clarification ,I was just repeating what I was told by YUNEEC support, and that in angle mode GPS was used to determine altitude.
Exactly. No one is critical of you but rather the support people who appear to have bad information.
 
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Exactly. No one is critical of you but rather the support people who appear to have bad information.
Right on brother ! However ,I did just get off the phone with the YUNEEC phone support agent and his response was in angle mode the barometer and GPS is used to verify altitude ,in manual mode obviously the barometer is used so ,take it for what it’s worth. Check out my thread on {E90 1.0.56 update possibly something wrong }
 

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