Lets talk about the DUAL gps claim..

[The Editor]

When you have two compass sensors which do not agree, how do you know which is correct?

Hence my post above!
For a true redundant system you need three of everything.

 

[The Editor]

Yeah. But a stuck gyro accelerometer won't let you take off.

Yes it will because it will initialise and accept it's attitude as zero offset. Only when it was airborne would the flight controller know that erroneous data was being received that didn't correspond to aircraft change of attitude.
Or....the accelerometers can get stuck (usually on one axis) once airborne.

 

[The Editor]

It's a dual compass that's new and should prevent the flyaways, not the dual GPS (That's been around for a while)

Dual compass and IMU made its debut on the P4

 

[Mad_Angler1]

The duel compass offers sensor redundancy but it won't save you from TBE especially if around heavy mag interference at take off location.

Users should ensure the takeoff point is clear of metal as before.

This whole flight control system has been solid on the P4 tbh and it should also mean the Mavic will be as well.

 

[cybertech]

In 1000+ flights of DJI drones ranging from the Vision+ to the P4 I have never lost GPS signal during a mission. I've never experienced a fly away either.

Lucky you.....

 

[maikm]

When you have two compass sensors which do not agree, how do you know which is correct?

When the drone yaws, the yaw amount can be measured by the gyros, and that value can be used to validate the change in compass readings. I don't know if DJI is doing that, but that's how I would implement it.

 

[m0j0]

Lucky you.....

I guess I'm just lucky too.


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[bakerboy]

What they mean is dual GNSS receivers, but people don't know what that means so they just say dual GPS

 

[cybertech]

I guess I'm just lucky too.


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For now.... [emoji14]

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[m0j0]

For now.... [emoji14]

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No for always! I don't exceed my abilities OR the performance of the AC. Surprise surprise I have had very few incidents across several platforms. That's even factoring in the lemon TH I had.


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[dewster]

Dual GPS, compasses, and an error checking processor is the reason I waited to buy. I've watched enough videos of P3 flyaways. I can't imagine it happening to the Mavic. Fingers crossed.


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[Wombat55]

Although dual GPS is not really to do with preventing fly-aways, it is simply used for better positional accuracy.
Now for the price point DJI cannot give true redundancy which requires three of each module. That way a comparison can be made between each of the three and if one starts giving differing data to the other two it can be switched out the system by the flight controller and all is well. With only having two of each sensor, if one gives some strange data there is no real way of knowing which of the two is feeding the erroneous information to the flight controller. So, no, dual modules DOES NOT mean no more fly-aways. However, DJI would have written in algorithms to the flight controller that will look at the data coming from the accelerometers and gyros whilst comparing the attitude of the aircraft with correlation to stick input. If the two do not agree, the erroneous IMU would be ignored.

I think that even just two GPS units can give a good deal of redundancy. True, if both GPS units are reporting somewhat similar but different coordinates then it would be difficult to impossible to determine which GPS unit is the defective one. But in my experience when electronic devices fail they tend to fail completely, not softly. In other words, if one of the GPS units develops a fault it's likely to start reporting completely nonsensical coordinates or stop reporting completely. In that case, it's easy to determine which GPS is still working.

Granted, a "majority vote" algorithm involving three or more GPS units would be simpler and more straightforward to implement, but it shouldn't be too difficult to implement an algorithm which can identify certain kinds of GPS unit failures and act accordingly to disqualify that GPS unit and turn control of the aircraft over to the remaining GPS unit.