172 Acre Drone Survey

[Malli35998]

I wanted to share my experience flying a relatively large survey.

Last week I completed a 172 acres drone survey over Fort McKavett about 20 miles west of Menard, TX. I used an Autel Evo II Enterprise Pro 6K RTK drone. Given the size of the survey, the way that Autel Explorer handles battery changes, and the windy conditions, I designed the survey into 5 overlapping sections with 3 different launch points (HPs). This also helped keep the maximum horizontal distance from the launch point to generally less than 1500 ft..

I planned on 10 GCPs but could only use 9 due to access limitations to one location. The GCPs were surveyed in using an EOS Arrow Gold GNSS RTK receiver. The closest TopNet Live (my NTRIP subscription service) base station was about 144KM away. I was able to connect to the base station and get RTK corrections. Even though I had the RTK module attached to the drone, I had the service turned off in the Explorer App.

Survey Specs:

• ~172-acres coverage area
• 5 overlapping sections
• 9 GCPs
• 250' AGL
• 80%/80% Overlap
• 13 MPG (I originally intended on flying at 15 mph but I confirmed I flew each section at 13 mph)
• GSD 0.5 in/px

The weather was clear but windy. On the day I flew the main (172 acre) survey the wind conditions were as follows (on-site weather station):

• Average Direction 161
• Max Direction 186
• Min Direction 133
• Average Wind 11
• Max Wind 17
• Min Wind 4
• Average Gust 16
• Max Gust 26
• Min Gust 8

I attached a screen capture summarizing some actual flight data. The longest flight time I was able to attain was ~29 min including take-off and landing. I generally set the Low Battery Warning to 18-20%. Wind likely played a factor as well.

Finally, the Smart Controller burns through it's charge relatively quickly under constant use. I plugged the Smart Controller into my Jackery Portable Power Station Explorer 240 to keep the Smart Controller charged. This seemed to work pretty well. I didn't notice the Smart Controller getting too hot (only slightly warm).

 

[Dave Pitman]

How did the processing go? Reported errors on Check points?

 

[Malli35998]

I use SimActive Correlator3D for processing. Overall, given the 144km distance to the closest base station, the processing results came out pretty well. I have attached the Processing Quality Report for your reference. Below is summary info.

Average XY error (m) 0.156
Average XYZ error (m) 0.192
RMS X error (m) 0.109
RMS Y error (m) 0.151
RMS Z error (m) 0.140
Average projection 0.83 pixels
error
Standard deviation 0.32 pixels
Number of GCPs 9

 

[Dave Pitman]

The reported errors for the GCPs seem high to me unless you are unsure of their accuracy.

Keep in mind that to be confident in a result, you need to use checkpoints. If relative accuracy is all you are going for then it's not necessary. For example. I've done topos where I target points placed by a surveyor where they don't share the coordinate with me. I refer to these as "blind check points". After processing, I tell them what the model is reporting for the point and they compare that with the actual coordinate that they measured and then they decide how accurate the model is.

 

[Malli35998]

I agree, the reported errors do seem a little high. I haven't normally used CPs but I likely will going forward. I am a one person company and self-taught. I checked the NGS for CORS, GPS stations to see if there were any in the immediate area. There are none. See attachment. Especially, in an isolated place like Fort McKavett, it is hard to get Surveyor support so I do the best I can with the tools and knowledge I have.

 

[Dave Pitman]

I was able to connect to the base station and get RTK corrections. Even though I had the RTK module attached to the drone, I had the service turned off in the Explorer App.

Can you elaborate on this statement? You had RTK toggled off probably because of the long baseline?

 

[Malli35998]

Yes, I had the drone RTK Module diabled in the Autel Explorer App. I did try and connect the RTK Module with my NTRIP network but it never would connect. I have read the base station must be less than 20KM away in order to work.

 

[Dave Pitman]

Gotcha. Are you able to connect and get a FIX without issue if you are closer to the station?

 

[Malli35998]

I am able to connect and get a FIX but sometimes it disconnects. I am new to RTK drones so still learning. I believe the Enterprise software is not as mature as the standard EVO II RTK.

 

[PhilC]

I wanted to share my experience flying a relatively large survey.

Last week I completed a 172 acres drone survey over Fort McKavett about 20 miles west of Menard, TX. I used an Autel Evo II Enterprise Pro 6K RTK drone. Given the size of the survey, the way that Autel Explorer handles battery changes, and the windy conditions, I designed the survey into 5 overlapping sections with 3 different launch points (HPs). This also helped keep the maximum horizontal distance from the launch point to generally less than 1500 ft..

I planned on 10 GCPs but could only use 9 due to access limitations to one location. The GCPs were surveyed in using an EOS Arrow Gold GNSS RTK receiver. The closest TopNet Live (my NTRIP subscription service) base station was about 144KM away. I was able to connect to the base station and get RTK corrections. Even though I had the RTK module attached to the drone, I had the service turned off in the Explorer App.

Survey Specs:

• ~172-acres coverage area
• 5 overlapping sections
• 9 GCPs
• 250' AGL
• 80%/80% Overlap
• 13 MPG (I originally intended on flying at 15 mph but I confirmed I flew each section at 13 mph)
• GSD 0.5 in/px

The weather was clear but windy. On the day I flew the main (172 acre) survey the wind conditions were as follows (on-site weather station):

• Average Direction 161
• Max Direction 186
• Min Direction 133
• Average Wind 11
• Max Wind 17
• Min Wind 4
• Average Gust 16
• Max Gust 26
• Min Gust 8

I attached a screen capture summarizing some actual flight data. The longest flight time I was able to attain was ~29 min including take-off and landing. I generally set the Low Battery Warning to 18-20%. Wind likely played a factor as well.

Finally, the Smart Controller burns through it's charge relatively quickly under constant use. I plugged the Smart Controller into my Jackery Portable Power Station Explorer 240 to keep the Smart Controller charged. This seemed to work pretty well. I didn't notice the Smart Controller getting too hot (only slightly warm).

I like the approach you'cve taken and appreciate you sharing the results as well as the process with us. Have you had any issues with the Jackery while charging batteries? The only time I've used one, it seemed to make my charger heat up a lot (while charging 1 battery), but I don't know for certain that the charger wasn't in the sun (on the front seat of the truck) some of the time), and now I'm reluctant to get one and use it for extending missions by keeping batteries charged....

 

[Pawel]

I wanted to share my experience flying a relatively large survey.

Last week I completed a 172 acres drone survey over Fort McKavett about 20 miles west of Menard, TX. I used an Autel Evo II Enterprise Pro 6K RTK drone. Given the size of the survey, the way that Autel Explorer handles battery changes, and the windy conditions, I designed the survey into 5 overlapping sections with 3 different launch points (HPs). This also helped keep the maximum horizontal distance from the launch point to generally less than 1500 ft..

I planned on 10 GCPs but could only use 9 due to access limitations to one location. The GCPs were surveyed in using an EOS Arrow Gold GNSS RTK receiver. The closest TopNet Live (my NTRIP subscription service) base station was about 144KM away. I was able to connect to the base station and get RTK corrections. Even though I had the RTK module attached to the drone, I had the service turned off in the Explorer App.

Survey Specs:

• ~172-acres coverage area
• 5 overlapping sections
• 9 GCPs
• 250' AGL
• 80%/80% Overlap
• 13 MPG (I originally intended on flying at 15 mph but I confirmed I flew each section at 13 mph)
• GSD 0.5 in/px

The weather was clear but windy. On the day I flew the main (172 acre) survey the wind conditions were as follows (on-site weather station):

• Average Direction 161
• Max Direction 186
• Min Direction 133
• Average Wind 11
• Max Wind 17
• Min Wind 4
• Average Gust 16
• Max Gust 26
• Min Gust 8

I attached a screen capture summarizing some actual flight data. The longest flight time I was able to attain was ~29 min including take-off and landing. I generally set the Low Battery Warning to 18-20%. Wind likely played a factor as well.

Finally, the Smart Controller burns through it's charge relatively quickly under constant use. I plugged the Smart Controller into my Jackery Portable Power Station Explorer 240 to keep the Smart Controller charged. This seemed to work pretty well. I didn't notice the Smart Controller getting too hot (only slightly warm).

Great job. Thanks for sharing your ideas and the way you approached the job. Which we must say was quite big as for a copter.
BTW - how long in total did it take to prepare while on site and fly?

 

[Malli35998]

To be honest this is the first time I have used the Jackery to charge a controller while in use. I was out in the sun but the weather was relatively cool and windy. I had no issues with the Jackery or the Smart Controller. I normally carry a portable umbrella and usb fans if it gets too hot outside. I didn’t need either for this survey.

 

[goldenu2]

Yes, I had the drone RTK Module diabled in the Autel Explorer App. I did try and connect the RTK Module with my NTRIP network but it never would connect. I have read the base station must be less than 20KM away in order to work.

I'm having similar issues: connects for a few seconds and disconnects. Autel is investigating, you might want to add your info.

 

[Dave Pitman]

I'm having similar issues: connects for a few seconds and disconnects. Autel is investigating, you might want to add your info.

I had the same issue. The fix for me was to upgrade the craft and Smart controller to the latest version ( Enterprise Firmware V2.1.67 and Smart Controller App V1.0.65 )

But before you go to the latest version, you need to factory reset the Smart Controller. For some reason, something in an earliar version of the app breaks the NTRIP module and it is not fixed by simply updating. It must be reset and then updated. Blade Strike and I worked on mine for a week before we found a resolution.

How I accomplished this was to install the latest firmware and app mentioned above. Then, I extracted the .apk for the app from the Smart Controller (because it's not available from Autel as a stand-alone .apk.). Then, I did a factory reset of the Smart Controller through Android Settings. Then, I side-loaded the app .apk directly. The problem was solved.

You may just be able to factory reset the Smart controller and then install the latest version mentioned above and have the same result, I don't know becuase that's not how I did it. If anyone wants to try using the steps I did but want to skip extracting the .apk from the SC, let me know by DM and I will share it. Or, just try reseting the SC and then install the latest firmware/app. Or, reinstall it if you already have installed it.

 

[Malli35998]

I just upgraded my drone and SC to V2.1.67 and APP to V1.0.65 . I plan to do some additional RTK testing early next week.

 

[Dave Pitman]

I just upgraded my drone and SC to V2.1.67 and APP to V1.0.65 . I plan to do some additional RTK testing early next week.

Hopefully you're good. But if you still have a problem, factory reset the Smart Controller and then update it back to .65 and you should be good.

 

[goldenu2]

I had the same issue. The fix for me was to upgrade the craft and Smart controller to the latest version ( Enterprise Firmware V2.1.67 and Smart Controller App V1.0.65 )

But before you go to the latest version, you need to factory reset the Smart Controller. For some reason, something in an earliar version of the app breaks the NTRIP module and it is not fixed by simply updating. It must be reset and then updated. Blade Strike and I worked on mine for a week before we found a resolution.

How I accomplished this was to install the latest firmware and app mentioned above. Then, I extracted the .apk for the app from the Smart Controller (because it's not available from Autel as a stand-alone .apk.). Then, I did a factory reset of the Smart Controller through Android Settings. Then, I side-loaded the app .apk directly. The problem was solved.

You may just be able to factory reset the Smart controller and then install the latest version mentioned above and have the same result, I don't know becuase that's not how I did it. If anyone wants to try using the steps I did but want to skip extracting the .apk from the SC, let me know by DM and I will share it. Or, just try reseting the SC and then install the latest firmware/app. Or, reinstall it if you already have installed it.

It would appear that the reset route worked! It has stayed connected for 3 solid minutes, which is far and away a record. I've got a number of flights to do tomorrow, will see if it actually functions. Thank you for being more responsive than the entire support team at Autel.

 

[FlyoverGreg]

I wanted to share my experience flying a relatively large survey.

Last week I completed a 172 acres drone survey over Fort McKavett about 20 miles west of Menard, TX. I used an Autel Evo II Enterprise Pro 6K RTK drone. Given the size of the survey, the way that Autel Explorer handles battery changes, and the windy conditions, I designed the survey into 5 overlapping sections with 3 different launch points (HPs). This also helped keep the maximum horizontal distance from the launch point to generally less than 1500 ft..

I planned on 10 GCPs but could only use 9 due to access limitations to one location. The GCPs were surveyed in using an EOS Arrow Gold GNSS RTK receiver. The closest TopNet Live (my NTRIP subscription service) base station was about 144KM away. I was able to connect to the base station and get RTK corrections. Even though I had the RTK module attached to the drone, I had the service turned off in the Explorer App.

Survey Specs:

• ~172-acres coverage area
• 5 overlapping sections
• 9 GCPs
• 250' AGL
• 80%/80% Overlap
• 13 MPG (I originally intended on flying at 15 mph but I confirmed I flew each section at 13 mph)
• GSD 0.5 in/px

The weather was clear but windy. On the day I flew the main (172 acre) survey the wind conditions were as follows (on-site weather station):

• Average Direction 161
• Max Direction 186
• Min Direction 133
• Average Wind 11
• Max Wind 17
• Min Wind 4
• Average Gust 16
• Max Gust 26
• Min Gust 8

I attached a screen capture summarizing some actual flight data. The longest flight time I was able to attain was ~29 min including take-off and landing. I generally set the Low Battery Warning to 18-20%. Wind likely played a factor as well.

Finally, the Smart Controller burns through it's charge relatively quickly under constant use. I plugged the Smart Controller into my Jackery Portable Power Station Explorer 240 to keep the Smart Controller charged. This seemed to work pretty well. I didn't notice the Smart Controller getting too hot (only slightly warm).

Thank you so much for the detailed experience you had. VERY helpful. A north Texan here and dying to buy the Evo 2 Enterprise RTK but I'm looking for anyone who has successfully connected their unit to an NTRIP service and then wanted to know what software they used to make the most of their data. Am currently using NTRIP with an Emlid Reach RS2 for high-accuracy GCPs, but wanting to see if I can get a more efficient workflow going with an RTK unit up in the air. Thanks for any insights . . .

 

[jmason702]

The reported errors for the GCPs seem high to me unless you are unsure of their accuracy.

Keep in mind that to be confident in a result, you need to use checkpoints. If relative accuracy is all you are going for then it's not necessary. For example. I've done topos where I target points placed by a surveyor where they don't share the coordinate with me. I refer to these as "blind check points". After processing, I tell them what the model is reporting for the point and they compare that with the actual coordinate that they measured and then they decide how accurate the model is.

So what are the surveyors saying about the accuracy of your Enterprize RTK unit?

 

[Dave Pitman]

So what are the surveyors saying about the accuracy of your Enterprize RTK unit?

I haven't done anything this winter that tied into a projected system. The majority of my calls are for construction progress orthos and stockpiles which don't require global accuracy and no engineers or surveyors involved. Hopefully the work for surveyors will start to pick up. Remember that the greater percentage of land being developed up here is heavily vegitated and non-Lidar drones aren't much help. I have nowhere near the interest needed to fund a Lidar rig.

How about you?