How to fly without using the compass

brett8883 · Oct 23, 2019

DanMan32 said:
VPS can't work at 120ft. 12ft maybe but not 120.

I mean it’s in the video above. Go to 4 minutes and I test it at different heights. I fly forward real fast and then release the sticks to see if it will brake or not. At about 120 feet it switches from Opti mode to Atti mode since it’s too far from the ground and starts to drift away. I was surprised too but the proof is in the pudding.

DanMan32 · Oct 23, 2019

That's surprising. Specs don't go nearly that high.

sar104 · Oct 24, 2019

brett8883 said:
I mean it’s in the video above. Go to 4 minutes and I test it at different heights. I fly forward real fast and then release the sticks to see if it will brake or not. At about 120 feet it switches from Opti mode to Atti mode since it’s too far from the ground and starts to drift away. I was surprised too but the proof is in the pudding.

VPS won't report height above 7 meters or so, and I've never seen an aircraft in OPTI mode at those heights. Log file?

DanMan32 · Oct 24, 2019

That's my thinking. However one possibility is that if in Opti mode below 7M it won't go any higher, but might pop into Opti at higher altitudes if it got there first in GPS.

I verified yesterday it stops showing VPS height at around 30ft.

brett8883 · Oct 24, 2019

sar104 said:
VPS won't report height above 7 meters or so, and I've never seen an aircraft in OPTI mode at those heights. Log file?

You know I wouldn’t deprive you of that. I made a new one for you and uploaded the uncut screen record so you can follow the log and the video.

This is a hack I did to make it so it doesn’t use GPS and it’s hard coded parameters so I’m sure nobody else has done this before. Required changing the max height without GPS parameter

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

Interesting observations:

I already knew this but some people will be surprised that OPTI mode is P-GPS mode without GPS. It is NOT ATTI mode + VPS.
You can have Sport mode in OPTI mode! Sport mode speeds but only uses VPS for positioning. I was surprised
Tapfly worked! I was surprised I thought it was GPS based but I guess it’s OA sensor and gyro driven
POI did not work. Expected
Waypoint did not work. Expecte
Course lock worked! Very surprised any intelligent flight modes worked but least surprised about this one since it still has a compass.
Positioning improved the closer I was to the ground. There is a shot where I’m looking straight down to show you how well it held position at different heights
I flew it one of the times I was using tapfly and it didn’t kick me to Atti mode till it was 140 feet above the home point meaning there isn’t just a hard height limit for OPTI mo

brett8883 · Oct 24, 2019

DanMan32 said:
That's my thinking. However one possibility is that if in Opti mode below 7M it won't go any higher, but might pop into Opti at higher altitudes if it got there first in GPS.

I verified yesterday it stops showing VPS height at around 30ft.

GPS was completely disabled. This is all hacked up so you can't use normal aircraft behavior logic for this

brett8883 · Oct 24, 2019

sar104 said:
VPS won't report height above 7 meters or so, and I've never seen an aircraft in OPTI mode at those heights. Log file?

Maybe it cant use VPS for height above 7 meters but it can use it for positioning. I always kinda thought the "VPS height" was the ultrasonic sensors anyway and was just poorly worded. Maybe it uses both idk but it can use vps for position for much further as you can see.

When I was in tap fly mode and then ascended over 130 some odd feet and it kicked me into atti mode it said the reason it couldn't stay in tap fly was because it it couldn't calculate velocity which I thought was interesting.

DanMan32 · Oct 24, 2019

Interesting. I've been trying to determine if VPS had any part in a seemingly benign toilet bowl effect I experienced last year. I finally analyzed the flight's TXT log with PhantomHelp where it had NA for VPS and in GPS mode. Height was 35ft. The flight was over water so I was figuring VPS was tracking water currents as a stationary pattern but then GPS telling it it was off course.

brett8883 · Oct 24, 2019

DanMan32 said:
Interesting. I've been trying to determine if VPS had any part in a seemingly benign toilet bowl effect I experienced last year. I finally analyzed the flight's TXT log with PhantomHelp where it had NA for VPS and in GPS mode. Height was 35ft. The flight was over water so I was figuring VPS was tracking water currents as a stationary pattern but then GPS telling it it was off course.

Could be the water just didn’t have enough contrast for VPS to work. I don’t think it can pick up on tides or anything that subtle.

sar104 · Oct 24, 2019

DanMan32 said:
Interesting. I've been trying to determine if VPS had any part in a seemingly benign toilet bowl effect I experienced last year. I finally analyzed the flight's TXT log with PhantomHelp where it had NA for VPS and in GPS mode. Height was 35ft. The flight was over water so I was figuring VPS was tracking water currents as a stationary pattern but then GPS telling it it was off course.

It's unlikely to produce TBE - that's caused by a steady ~ 90° heading error.

sar104 · Oct 24, 2019

brett8883 said:
You know I wouldn’t deprive you of that. I made a new one for you and uploaded the uncut screen record so you can follow the log and the video.

This is a hack I did to make it so it doesn’t use GPS and it’s hard coded parameters so I’m sure nobody else has done this before. Required changing the max height without GPS parameter

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

Interesting observations:

I already knew this but some people will be surprised that OPTI mode is P-GPS mode without GPS. It is NOT ATTI mode + VPS.

You can have Sport mode in OPTI mode! Sport mode speeds but only uses VPS for positioning. I was surprised

Tapfly worked! I was surprised I thought it was GPS based but I guess it’s OA sensor and gyro driven

POI did not work. Expected

Waypoint did not work. Expecte

Course lock worked! Very surprised any intelligent flight modes worked but least surprised about this one since it still has a compass.

Positioning improved the closer I was to the ground. There is a shot where I’m looking straight down to show you how well it held position at different heights

I flew it one of the times I was using tapfly and it didn’t kick me to Atti mode till it was 140 feet above the home point meaning there isn’t just a hard height limit for OPTI mo

VPS is certainly working at much higher altitudes than the vision height measurement:

Vision height is reporting up to 16 meters (higher than I've seen before), but VPS is not quitting until around 40 meters when climbing, and is restored around 20 meters on descent.

brett8883 · Oct 25, 2019

sar104 said:
VPS is certainly working at much higher altitudes than the vision height measurement:

View attachment 84110

Vision height is reporting up to 16 meters (higher than I've seen before), but VPS is not quitting until around 40 meters when climbing, and is restored around 20 meters on descent.

Thanks for doing that!