Hoverfly Hoverfly GPS saved my ship! I nearly had a Heart Attack! 2013 Demo Reel.

[mspencer1]

I was flying by line of sight last weekend at a local university (Yes we had permission). The front of the school is heavily wooded so lots of obstacles. Some trees are more than 100 feet. My cameraman asked me to slowly ascend up a 100 foot tree. So I would not hit the tree I did it by line of sight not FPV. However, line of sight is difficult to tell when your at the top of the tree. My FPV ground station was setup 50 feet from me. As I got to the top of the tree my cameraman's video signal cut out due to interference. He normally will let me know if i'm at or above the obstacle but not this time. The ship got high enough that I had line of sight control issues. It then began moving beyond the tree (other side) and out of visual contact. HOLY SH*T! I then activated position holding. I then heard a familiar WOOOSH (the sound of props fighting the air). Still out of sight I was convinced the ship was coming down. "This is it" I said. Then It inched its way back into view above the tree at 300 feet! I then used GPS slewing to move the ship back towards us and slowly lowered it down. I landed it and then I laid on the ground for a minute. I confirmed the altitudes later from the FPV recording and OSD. The point of my story is the GPS works very well for me with 4.8 and an external mag. I've been flying this particular octo for 100 hours now and it has been 100% reliable. I use the GPS to take the workload off me when my cameraman needs me to hold for a moment. If I'm flying by FPV and beyond sight distance I use the RTH to help me out. It always works for me. Its unfortunate it doesn't work for others. I have a identical sister ship with the same setup and GPS performs flawlessly.
http://vimeo.com/77811975

 

[trgbox]

I use the auto return to home, in those situations and sit down and watch it do it all by itself. I also find the intelligent orientation works a treat for 360deg panning around a target. Nice vid!

 

[jes1111]

Two "first posters" talking up Hoverfly GPS? Smells like...

 

[mspencer1]

GPS Performance

I use the auto return to home, in those situations and sit down and watch it do it all by itself. I also find the intelligent orientation works a treat for 360deg panning around a target. Nice vid!

Thanks! I should give that a try. I've never used the Orientation Lock because I was afraid I might get disoriented forgetting thats its ON. When I don't have the camera rig attached (fun flying) I do land the ship with PH or RTH ON. I even take off again with it ON. Earlier in the year I did try out a Zero UAV YS-X6. Lots of features but user friendliness was crap not too mention customer support. In 100+ hours of flying this one ship I've never had a GPS issue. I've had motor cook but the ship flew fine without it. It was intermittent at first causing the ship to dip quickly and recover several times until it fried. Firmware 4.8 (for me) put my trust back into it. Prior to 4.8 GPS worked for crap not too mention some bugs that developed around 4.3.
I'm just wondering why so many are complaining about the GPS performance. Mine holds in a 3 meter radius. Maybe this isn't good enough for many others. Some even still get the toilet bowl effect. That can be eliminated by twisting the mag left or right. I use the heading on the OSD to determine if there is any Magnetic Deviation (RF interference) playing with the Mag. Easy to find and easy to fix by raising it up. I'm guessing the ones that complain the most about GPS don't want to figure these things out. They want Plug-n-Play.

 

[Jareth_Atian]

Interesting. Is the magnetic compass located in the external GPS receiver or on the HF GPS board itself? I only ask since there is nothing at all in HoverflyGPS User Manual or knowledge-base about orienting the GPS unit (except stating that the antenna must be pointed upward), so I assumed that the compass was on the board itself (and thus, unable to be twisted).

There is a note in the knowledgebase about setting up an external compass/magnetometer by hacking together some parts from sparkfun. Is that what you've done?

 

[mspencer1]

Interesting. Is the magnetic compass located in the external GPS receiver or on the HF GPS board itself? I only ask since there is nothing at all in HoverflyGPS User Manual or knowledge-base about orienting the GPS unit (except stating that the antenna must be pointed upward), so I assumed that the compass was on the board itself (and thus, unable to be twisted).

There is a note in the knowledgebase about setting up an external compass/magnetometer by hacking together some parts from sparkfun. Is that what you've done?

Yes I used the axis external 3 magnetometer from Sparkfun. The internal magnetometer is soldered directly on the Hoverfly GPS board. Because of this it is subject to poor installation positioning and interference. DJI and Zero UAV have their Magnetometer and GPS antenna located high up and away from all the electronics to prevent this. I like Hoverfly's idea to have the magnetometer located on the GPS board but it was not a good one. When you install your Hoverfly boards there is going to be a slight inaccuracy in the installation. The whole unit must be facing perfectly forward so the Magnetometer knows where the front of the ship is. Even the installation of the magnetometer onto the GPS board may not be perfect. If the external mag is installed it can be repositioned if necessary. The circling problem is a simple fix. If the ship circles left, twist the magnetometer left (slightly) and vice versa. If your thinking the esc's and other electronics are interfering with the compass reading you must use the OSD so you can see the heading. With your ship flight ready. Start adding power. If you see a shift in the compass heading before it gets off the ground you have interference.

 

[DucktileMedia]

I found my HFP RTH to work very smoothly and reliably although the position accuracy was very LARGE. I'd say it would return within 30-40' of where it started. This was the same for the GPS hold. I also felt that the waiting time for the GPS to lock onto enough sats was over 2-3 minutes average while my Woochang would do it in 30 seconds or less. Ultimately I ended up taking off the gps just for that reason but just agreeing that the RTH was solid for me as well.

 

[Bartman]

you shouldn't have to move the magnetometer, declination values are preloaded in the GPS firmware. inaccuracy in installation isn't exactly correct either as CNC machined parts are accurate to a few thousandths.

it does work fairly well once interference is accounted for, it just isn't as good as some of the other units. 3M of wandering can be bad when you're inching up to a branch on a windy day to get the shot you have in mind.

 

[mspencer1]

you shouldn't have to move the magnetometer, declination values are preloaded in the GPS firmware. inaccuracy in installation isn't exactly correct either as CNC machined parts are accurate to a few thousandths.

it does work fairly well once interference is accounted for, it just isn't as good as some of the other units. 3M of wandering can be bad when you're inching up to a branch on a windy day to get the shot you have in mind.

You can get installation inaccuracy. I've had it before. If you drill your own holes to mount the FC this could happen. Nothing is perfect.

 

[mspencer1]

I found my HFP RTH to work very smoothly and reliably although the position accuracy was very LARGE. I'd say it would return within 30-40' of where it started. This was the same for the GPS hold. I also felt that the waiting time for the GPS to lock onto enough sats was over 2-3 minutes average while my Woochang would do it in 30 seconds or less. Ultimately I ended up taking off the gps just for that reason but just agreeing that the RTH was solid for me as well.

I agree. It sometimes returns to home in an arc if there is wind. Getting itself back to the home position is sometimes very slow once its within 30-40'. It inches its way back from there for me usually. The earlier versions of the firmware stopped to abruptly causing over shoot. Now its the opposite. As far as the GPS lock goes I get a lock in under a minute (Usually way less). Thats because i'm not using the standard mediatek GPS unit. I'm using the Mediatek 3DR unit. It has a battery onboard for Hot starts. Cold starting gps units (no battery for memory) take forever! Simple fix.

 

[Jareth_Atian]

Thank you very much for your suggestions. If all that it will take to make the Hoverfly GPS behave almost as well as their competition is hacking together a collection of aftermarket parts and using information that isn't present anywhere in Hoverfly's documentation, then I'm definitely willing to give it a try.

 

[mspencer1]

The error i'm speaking of is the Magnetometer not facing the front of the ship perfectly. For whatever that reason may be (chip installation or FC installation) the magnetometer tells the ship what direction to fly. If the front of the ship doesn't match (even by a couple degrees) it will arc what should be a straight flight path or circle when holding.

 

[mspencer1]

Thank you very much for your suggestions. If all that it will take to make the Hoverfly GPS behave almost as well as their competition is hacking together a collection of aftermarket parts and using information that isn't present anywhere in Hoverfly's documentation, then I'm definitely willing to give it a try.

All you need is the $15 magnetometer from Spark Fun and 2 10K resistors (Radio Shack). Then maybe a little soldering.

 

[Stacky]

Question regarding calibration of GPS board. A friend of mine has lent me his GPS board to try out. He has never actually used it so doesnt know for sure. Im a little confused with respect to doing the temperature calibration. I have happily got the hang of this on the HFP board but in the manual its a little vague. Do I do the temperature calibration on the GPS board while its plugged in to the HFP?. Or do I calibrate the GPS board seperately from calibrating the HFP board.

 

[mspencer1]

Question regarding calibration of GPS board. A friend of mine has lent me his GPS board to try out. He has never actually used it so doesnt know for sure. Im a little confused with respect to doing the temperature calibration. I have happily got the hang of this on the HFP board but in the manual its a little vague. Do I do the temperature calibration on the GPS board while its plugged in to the HFP?. Or do I calibrate the GPS board seperately from calibrating the HFP board.

The GPS board doesn't need to be temperature calibrated. The temperature calibration is for the Gyros on the main board. As the gyros heat up they begin to drift. The temperature calibration records this change and makes the necessary corrections. It doesn't matter if the GPS board is attached or not during the temperature calibration procedure. I do mine with the GPS board removed so the hot air coming from the blow dryer has no obstacles on its way to the main board. Just make sure your at least 3 feet away with the blow dryer during calibration.

 

[Stacky]

Thanks for that, I worked it out so thats all done.
The next problem I have is that right now I cant do the compass calibration however my understanding is that the HFP should still be able to fly even if the GPS board is in place but the functions not being used.
Is that correct?
What is happening right now is that the GPS board has the purple led flashing which wont go away so I am unable to arm the HFP board. Do you know if I have to have done the compass calibration to get past this problem?
I have to wait for a friend to drop by with his laptop so i can do the compass calibration outside.
Cheers

oops just read the guide again and see I dont need the computer connected .... ha! But should I still be able to fly without using the GPS functions?, should that purple led go away?

 

[mspencer1]

Thanks for that, I worked it out so thats all done.
The next problem I have is that right now I cant do the compass calibration however my understanding is that the HFP should still be able to fly even if the GPS board is in place but the functions not being used.
Is that correct?
What is happening right now is that the GPS board has the purple led flashing which wont go away so I am unable to arm the HFP board. Do you know if I have to have done the compass calibration to get past this problem?
I have to wait for a friend to drop by with his laptop so i can do the compass calibration outside.
Cheers

oops just read the guide again and see I dont need the computer connected .... ha! But should I still be able to fly without using the GPS functions?, should that purple led go away?

Yes you should be able to fly even if you haven't done any calibrations but not recommended. The purple LED will be flashing for a number of reasons. 1. The ship type isn't selected (it doesn't know what configuration your flying). 2 The Receiver isn't connected to the HFP properly. 3. The USB is plugged in. 4. There is a Gyro or Accelerometer failure. Usually its 1 and 2. When you try to arm the board are you hearing beeping? How many beeps?

 

[Stacky]

Yes you should be able to fly even if you haven't done any calibrations but not recommended. The purple LED will be flashing for a number of reasons. 1. The ship type isn't selected (it doesn't know what configuration your flying). 2 The Receiver isn't connected to the HFP properly. 3. The USB is plugged in. 4. There is a Gyro or Accelerometer failure. Usually its 1 and 2. When you try to arm the board are you hearing beeping? How many beeps?

Thanks for that. I was able to get it to start up so thats good. Just sorting out a proper way to mount the gps antenna and hopefully give it a test this evening or tomorrow.
Cheers

 

[mspencer1]

Thanks for that. I was able to get it to start up so thats good. Just sorting out a proper way to mount the gps antenna and hopefully give it a test this evening or tomorrow.
Cheers

Good to know. Let me know if you have any problems.

 

[Stacky]

Ok, next silly question...

I have the same firmware running on the GPS and the HFP board. I have been able to do the temperature, accelerometer and temperature calibrations successfully.
I have been able to do the compass calibration successfully outside and the correct checkboxes work at the right time in the main tab, eg: AH, AL, PH, RTH. On the GPS tab the map comes up successfully and the satelittes show a number of satillites connected. The compass calibration box is checked as is the GPS connection.
When outside I get a blue led on the GPS board and can take off an fly.

However when I took the X8 to the flying field I couldnt see any reaction to the PH being enabled and when I flew the X8 away and tried RTH nothing happened.
My AL and AH were working well.

I will be doing something daft but at this point all the indicators are telling me the GPS board is calibrated and set up correctly and responding on the setup software to the switch inputs but out in the field there appears to be no GPS functions when flying.