Does ADS-B not take into account height?  A few times I've got the Piloted Aircraft nearby warning, only to look around and see a commercial airliner 30,000 feet above.  If it constantly warns for airplanes that could never possibly be a concern it will lead to people ignoring it.  

No, for some reason it only looks at the horizontal position of an aircraft, not altitude. Odd, I know.

Hello there sbarton. Good day and thank you for reaching out. The DJI AirSense is an alert system that uses ADS-B technology to give drone pilots enhanced situational awareness and help them make responsible decisions while flying. This feature gathers flight data sent automatically from nearby aircraft with ADS-B transmitters, analyzing it to detect potential collision risks and alert users well in advance through the DJI mobile application. In addition I will post a DJI link where in you can read more about the DJI AirSense ( https://www.dji.com/flysafe/airsense ). Thank you.

If that have the position of the "nearby" aircraft, they have height as well. So it shouldn't be a problem to add that. This discussion was already going on with the Mavic Air 2. I don't know why they don't implement it sensibly.

DJI Stephen Posted at 4-27 20:51
Hello there sbarton. Good day and thank you for reaching out. The DJI AirSense is an alert system that uses ADS-B technology to give drone pilots enhanced situational awareness and help them make responsible decisions while flying. This feature gathers flight data sent automatically from nearby aircraft with ADS-B transmitters, analyzing it to detect potential collision risks and alert users well in advance through the DJI mobile application. In addition I will post a DJI link where in you can read more about the DJI AirSense ( https://www.dji.com/flysafe/airsense ). Thank you.

Thanks Stephen.  I understand what ADS-B is and how it works.  My concern is how it is currently implemented will lead to pilots ignoring it for giving tons of false alarms.  If you live in an area where there is a mix of small aircraft flying low and large aircraft flying high, constantly seeing warnings for high flying commercial airliners 30,000' above that have zero chance of an incident, I don't want that to show up on my screen.  I want to know about the low flying aircraft that has a chance of getting near me.  Can you raise this issue with DJI to use height information, not just radius info when determining the ADS-B warnings.  Thanks!  

sbarton Posted at 4-28 09:14
Thanks Stephen.  I understand what ADS-B is and how it works.  My concern is how it is currently implemented will lead to pilots ignoring it for giving tons of false alarms.  If you live in an area where there is a mix of small aircraft flying low and large aircraft flying high, constantly seeing warnings for high flying commercial airliners 30,000' above that have zero chance of an incident, I don't want that to show up on my screen.  I want to know about the low flying aircraft that has a chance of getting near me.  Can you raise this issue with DJI to use height information, not just radius info when determining the ADS-B warnings.  Thanks!

If I understood ADS-B correctly, it‘s just some sort of ping without information about the aircrafts height or position. Only the strength of the signal can be used to determine if an aircraft is far away or near. Maybe thats why it should be hard to implement some sort of height filter.
But correct me if I‘m wrong.

Vertigocal Posted at 4-28 10:07
If I understood ADS-B correctly, it‘s just some sort of ping without information about the aircrafts height or position. Only the strength of the signal can be used to determine if an aircraft is far away or near. Maybe thats why it should be hard to implement some sort of height filter.
But correct me if I‘m wrong.

From what I've read ADS-B has GPS info, height, velocity, heading, etc.  Not sure why DJI would implement it with only signal strength.  

Vertigocal Posted at 4-28 10:07
If I understood ADS-B correctly, it‘s just some sort of ping without information about the aircrafts height or position. Only the strength of the signal can be used to determine if an aircraft is far away or near. Maybe thats why it should be hard to implement some sort of height filter.
But correct me if I‘m wrong.

ADS-B contains, among other things, speed, heading and flight level (Height based on a standard pressure setting of 1013.2mb at sea level), current position & aircraft unique identification as a hex value.

This is the same data that is used by Plane Finder and the like. If the aircraft is not transponding with Mode-S selected then the drone won't have any data to work with.

It was mandated in the UK that all aircraft should be fitted with a Mode-S transponder if practicable, most light aircraft owners delayed for as long as they could to implement due to the lack of cost vs benefit to the pilot. It's not a legal requirement to carry a transponder as yet.

I would have expected that distance and height would have been resolved by the drones firmware as a minimum. Maybe it will improve with future firmware updates.

I think the drone would need a barometer in order to insure the height information was accurate. I'm guessing DJI would rather just report all aircraft than risk providing bad height information. That said, I'd still think GPS would get you in the ballpark of the correct altitude.

I received my first aircraft warning notification in a flight yesterday. I thought the warning included the words "low flying" (I'm not sure about this). I immediately decreased the altitude to the lowest level where I could still maintain a video image and headed home. I didn't want the drone to use RTH since the RTH level was higher than where I could fly the drone myself.

honestly - this whole AIR sense nonsense is worth almost nothing on a FPV drone in my opinion. If you really fly fpv you should already catch the fact that flying hi is as boring as hell ...

It would make it too complicated to have it more narrowed.  Keeping it in radius mode makes it where it doesn't interfere too much w/ the other important stuff the drone has to do w/ super low latency.  The warning is indeed ignored but it has to be there.  Better than nothing of course.

It would be ideal to be able to have an arrow on the goggles to know where the aircraft is and how far it is from the drone but we can only have so much.

AntDX316 Posted at 4-29 04:48
It would make it too complicated to have it more narrowed.  Keeping it in radius mode makes it where it doesn't interfere too much w/ the other important stuff the drone has to do w/ super low latency.  The warning is indeed ignored but it has to be there.  Better than nothing of course.

It would be ideal to be able to have an arrow on the goggles to know where the aircraft is and how far it is from the drone but we can only have so much.

Complicated?  It's simple subtraction.  Plane height minus drone height.  If that difference is greater than some number, don't display.  

I think adding more clutter on the screen would offset any benefit of reporting the aircraft's height. A huge red warning with a bunch of numbers and arrows on it suddenly appearing  and blotting out half the screen while you're proximity flying is a safety hazard, IMO. FPV with goggles isn't like an aircraft cockpit, or FPV with a smart device where you can dismiss the popup with your finger, etc.; you're at the mercy of whatever little screen real estate you have and you can't dismiss the warnings. So to me the value of reporting altitude in the goggles is probably pretty low.

At the altitudes we fly, if the full-size powered aircraft is anywhere near becoming a hazard, you can hear it already, or your spotter can. That's good info you can use to give way to the aircraft too.

I like it the way it is, just a small, non-intrusive warning that an aircraft is approaching...

Duane Degn Posted at 4-28 11:39
I think the drone would need a barometer in order to insure the height information was accurate. I'm guessing DJI would rather just report all aircraft than risk providing bad height information. That said, I'd still think GPS would get you in the ballpark of the correct altitude.

I received my first aircraft warning notification in a flight yesterday. I thought the warning included the words "low flying" (I'm not sure about this). I immediately decreased the altitude to the lowest level where I could still maintain a video image and headed home. I didn't want the drone to use RTH since the RTH level was higher than where I could fly the drone myself.

The drone has a barometer.

bjr981s Posted at 4-29 08:53
The drone has a barometer.

"The drone has a barometer."

I wouldn't be surprised but I have yet to see it in any of the teardown videos. Do you have any idea where the barometer is located in the drone?

Are you sure it has a barometer or do you assume it does since it seems like it should? If you're sure it does, how do you know?

There are a couple places on the drone where a barometer could be hiding but it's generally pretty easy to identify barometers and I haven't seen one in this drone yet.

Duane Degn Posted at 4-29 09:44
"The drone has a barometer."

I wouldn't be surprised but I have yet to see it in any of the teardown videos. Do you have any idea where the barometer is located in the drone?

the way the height is being displayed suggest that this drone has een baro sensor indeed. The height changes with speed and is off by many meters sometimes, unless you fly very low to the ground and the hi precision sensor kicks in ... this one seems very reliable so far ...

tomekyo Posted at 4-29 12:12
the way the height is being displayed suggest that this drone has een baro sensor indeed. The height changes with speed and is off by many meters sometimes, unless you fly very low to the ground and the hi precision sensor kicks in ... this one seems very reliable so far ...

I think the drone uses the distance sensors at low altitude but I think the drone could be using GPS to measure altitude when it's not close to the ground. I haven't found any documentation stating the drone has a barometer. I'm not saying it doesn't, I just haven't seen proof it does.

I think many of us have seen barometers on other flight controllers and I'd think we'd be able to recognize a barometer on the new drone if we knew where to look.

I haven't found a source of photos showing both sides of all the PCBs in the FPV drone. So it is certainly possible a barometer is hiding somewhere in the drone.

I also haven't found anyway to access barometer data in the logs. This doesn't mean there isn't a barometer but I think there's sufficient reason not to be sure one exists in the drone.
Edit: The drone does indeed have a barometer. I'll post photos in a separate thread tomorrow.

luciens Posted at 4-29 07:59
I think adding more clutter on the screen would offset any benefit of reporting the aircraft's height. A huge red warning with a bunch of numbers and arrows on it suddenly appearing  and blotting out half the screen while you're proximity flying is a safety hazard, IMO. FPV with goggles isn't like an aircraft cockpit, or FPV with a smart device where you can dismiss the popup with your finger, etc.; you're at the mercy of whatever little screen real estate you have and you can't dismiss the warnings. So to me the value of reporting altitude in the goggles is probably pretty low.

At the altitudes we fly, if the full-size powered aircraft is anywhere near becoming a hazard, you can hear it already, or your spotter can. That's good info you can use to give way to the aircraft too.

No one is suggesting adding airplanes height info to the on screen display.  I agree it would be clutter and too much info to process.  What I'm saying is that the DJI Drone should have the capability of determining distance using height easily and using logic as to when to show the warning based on whether the plane has a possibility of being a threat.   This would reduce unnecessary clutter on the screen as it would reduce the amount of times the Aircraft Warning message shows up.  It would also make it so that you know that if you see the Aircraft Warning message, you know that it could be an issue.  You don't have to 2nd guess the message or use your eyes and ears to find the airplane for yourself before taking action.  

bjr981s Posted at 4-29 08:53
The drone has a barometer.

Pretty sure it has a barameter as well.  Most of their older ones did.  Can't see them "cheaping out" on this unit.  Don't they use barometer and compass when they don't have a GPS fix?  

Duane Degn Posted at 4-29 13:57
I think the drone uses the distance sensors at low altitude but I think the drone could be using GPS to measure altitude when it's not close to the ground. I haven't found any documentation stating the drone has a barometer. I'm not saying it doesn't, I just haven't seen proof it does.

I think many of us have seen barometers on other flight controllers and I'd think we'd be able to recognize a barometer on the new drone if we knew where to look.

The IMU has a barometer. You cant use GPS for height the HDOP is not accurate enough.

Its OK for aircraft etc good for +- a few hundred feet. Useless fo a drone.

sbarton Posted at 4-30 05:13
No one is suggesting adding airplanes height info to the on screen display.  I agree it would be clutter and too much info to process.  What I'm saying is that the DJI Drone should have the capability of determining distance using height easily and using logic as to when to show the warning based on whether the plane has a possibility of being a threat.   This would reduce unnecessary clutter on the screen as it would reduce the amount of times the Aircraft Warning message shows up.  It would also make it so that you know that if you see the Aircraft Warning message, you know that it could be an issue.  You don't have to 2nd guess the message or use your eyes and ears to find the airplane for yourself before taking action.

I really can't agree. Determining that isn't something we want DJI doing for us - we're responsible for threat assessment in our flights, not DJI. They already take away enough control from the pilot with the NFZs, altitude limits and geofencing, I don't think it's a good idea to encourage them to do more of that, because they probably will. Which will just make the drone even harder to use than it already is.

Its our job as pilots to "see and avoid", and determine threat levels of other aircraft in our area, not DJI or ADS-B. ADS-B is just a tool for us. I think the initial warning is sufficient right now to alert the pilot and spotter, so we can begin assessing the situation ourselves.

So I don't really know a good solution to the altitude reporting that's not overly intrusive on the real estate in the goggles.  I think for now the warning as-is is acceptable, until a good user interface that shows altitude is come up with.

bjr981s Posted at 4-30 06:13
The IMU has a barometer. You cant use GPS for height the HDOP is not accurate enough.

Its OK for aircraft etc good for +- a few hundred feet. Useless fo a drone.

Is your reply "The IMU has a barometer" in response to my question about where the barometer is located?

If you're referring to the shock mounted IMU above the camera, I can assure you, a barometer is not hiding in that location. The small shock mounted PCB has a metal heatsink sandwiched against it. The entire PCB is smothered in blue thermal paste. I think I can safely say there is not a barometer on the IMU PCB.

Again, I'm not positive the drone does not have a barometer but I'm starting to doubt it does. I can't find it anywhere.

I think the GPS supplemented with the IMU may be enough data for the drone to hold altitude well.

If the drone does have a barometer, I would have thought it would be mentioned in the manual. I also think we should be able to find it on the drone.
Edit: The drone does have a barometer. It is pretty well hidden. I'll post photos showing the barometer tomorrow in a separate thread.

luciens Posted at 4-30 06:21
I really can't agree. Determining that isn't something we want DJI doing for us - we're responsible for threat assessment in our flights, not DJI. They already take away enough control from the pilot with the NFZs, altitude limits and geofencing, I don't think it's a good idea to encourage them to do more of that, because they probably will. Which will just make the drone even harder to use than it already is.

Its our job as pilots to "see and avoid", and determine threat levels of other aircraft in our area, not DJI or ADS-B. ADS-B is just a tool for us. I think the initial warning is sufficient right now to alert the pilot and spotter, so we can begin assessing the situation ourselves.

The warning as is right now is not acceptable though.  I should not see a warning for a commercial airliner cruising at 30,000 feet above me when I'm at 150 feet.  I also live in an area where small aircraft fly at lower altitudes.  I do not want a warning for every commercial airliner that is thousands of feet above but I do want a warning for planes  that are at an altitude and/or vicinity that I do need to worry about.  Otherwise how do I know if it is a commercial airliner that I don't need to worry about or a plane flying lower that I do need to worry about?  If the false alarm warnings become too many then they may be ignored or not taken seriously.  Instead there needs to be a way to filter out warnings that are definitely false alarms.  This should be easy to do.  

sbarton Posted at 4-30 08:13
The warning as is right now is not acceptable though.  I should not see a warning for a commercial airliner cruising at 30,000 feet above me when I'm at 150 feet.  I also live in an area where small aircraft fly at lower altitudes.  I do not want a warning for every commercial airliner that is thousands of feet above but I do want a warning for planes  that are at an altitude and/or vicinity that I do need to worry about.  Otherwise how do I know if it is a commercial airliner that I don't need to worry about or a plane flying lower that I do need to worry about?  If the false alarm warnings become too many then they may be ignored or not taken seriously.  Instead there needs to be a way to filter out warnings that are definitely false alarms.  This should be easy to do.

Well maybe DJI can come up with an unobtrusive way of displaying the altitude in the warning itself. If it's sufficiently small, maybe it can be done without additional distraction.

Keep in mind too, though, that not all aircraft have ADS-B transponders in them. Many smaller light aircraft of the type we need to be concerned about don't have ADS-B and many never will have a transponder of any type in them.

So it's not something you want to depend on. Even if it's enhanced, it can still fail you for aircraft that aren't transponder-equipped. You still need to see & avoid as part of just general situational awareness anyway.

Duane Degn Posted at 4-29 09:44
"The drone has a barometer."

I wouldn't be surprised but I have yet to see it in any of the teardown videos. Do you have any idea where the barometer is located in the drone?

The barometer is about 4 mm by 4 mm and looks like a SMT resister.

tomekyo Posted at 4-28 12:46
honestly - this whole AIR sense nonsense is worth almost nothing on a FPV drone in my opinion. If you really fly fpv you should already catch the fact that flying hi is as boring as hell ...

Indeed, flying is boring.  Still though, it's a lot quicker in the DJI FPV drone when flying high than it is w/ the M2P/M2Z.  Those feel incredibly slow when it gets into wind speed warning mode in Sports mode.

bjr981s Posted at 5-1 02:16
The barometer is about 4 mm by 4 mm and looks like a SMT resister.

"The barometer is about 4 mm by 4 mm and looks like a SMT resister."

I think you're right about the drone having a barometer but I don't think the part you are describing is the barometer.

As I mentioned in edits to earlier posts, the barometer is pretty well hidden inside the drone. Here's a photo of what I believe is the barometer.


The chip which I believe is the barometer is about 2mm by 2mm. In order to photograph the sensor, I've pulled back the open cell foam which protects the chip. If you think this isn't a barometer, I'm hoping you'll let me know why.

Here's a photo of the inside of the IMU enclosure.

The IMU enlosure was pretty much full of the blue thermal paste. I'm confident a barometer wouldn't be covered in thermal paste which is why I continued disassembling my drone.

I'll post a new thread to share some of the photos I've recently taken of my disassembled drone. I'm hoping for help in identifying the various parts.

This is a drone barometer. I use them to repair Walkera Flight Controllers.



FYI the IMU is not a single can of electronics. It is distributed.

Cheers

bjr981s Posted at 5-2 06:22
This is a drone barometer. I use them to repair Walkera Flight Controllers.

[view_image]

"This is a drone barometer."
I initially expected to find a barometer which looks like the one you pictured. This was one reason I started to incorrectly think the done might not have a barometer.

"FYI the IMU is not a single can of electronics. It is distributed."

Which is why I wrote:
"If you're referring to the shock mounted IMU above the camera, I can assure you, a barometer is not hiding in that location."

I was hoping to find the location of the barometer.

The chip which I believe is the barometer doesn't look like one of the half dozen barometer chips I've used in the past but I still think it's the barometer since it was under open cell foam and I can't think of what else it could be. I also don't see any other parts which look like they could be barometers. I think it's safe to assume the barometer would not be inside one of the many RF sheilding cans.

Duane Degn Posted at 5-2 08:04
"This is a drone barometer."
I initially expected to find a barometer which looks like the one you pictured. This was one reason I started to incorrectly think the done might not have a barometer.

You are correct, it would be shielded fm any rapid moving air.

Most likely cell foam.