Looking for tips on obtaining 6" accuracy with drone mapping

[Darcy]

We're a landscaping company considering using a drone to measure sites for estimating. Our main focus is to generate orthomaps accurate to within 6", with mapping topography being second priority. What will it take to obtain this level of accuracy? Do we need to use GCPs? If yes, what level/type of GPS sensor will we need to establish the positions of the GCPs? I'm assuming a smartphone's built-in GPS isn't accurate enough. Or will a drone's built-in GPS without RTK/PPK provide accurate imagery geotags without GCPs?

As you've maybe guessed already, I'm totally new to drone mapping so I'm looking for beginner-level advice here.

 

[David_Cambridge]

6” accuracy will be a real issue. You will need a specialized drone and associated equipment for that accuracy level. The normal gps systems used are specced for accuracies of +- 16 feet 95% of the time.

 

[Meta4]

Our main focus is to generate orthomaps accurate to within 6", with mapping topography being second priority. What will it take to obtain this level of accuracy? Do we need to use GCPs? If yes, what level/type of GPS sensor will we need to establish the positions of the GCPs?

Yes .. you can get good accuracy with a P4 pro but you will need GCPs for accuracy.
This article will give you some more info:

How Accurate Are Drone Aerial Maps? - Wilcox Environmental Engineering, Inc.

www.wilcoxenv.com

Here's a link to some popular terrestrial units suitable for locating GCP data: Emlid – RTK GNSS receivers and accessories

 

[Lou101]

We're a landscaping company considering using a drone to measure sites for estimating. Our main focus is to generate orthomaps accurate to within 6", with mapping topography being second priority. What will it take to obtain this level of accuracy? Do we need to use GCPs? If yes, what level/type of GPS sensor will we need to establish the positions of the GCPs? I'm assuming a smartphone's built-in GPS isn't accurate enough. Or will a drone's built-in GPS without RTK/PPK provide accurate imagery geotags without GCPs?

As you've maybe guessed already, I'm totally new to drone mapping so I'm looking for beginner-level advice here.

Darcy,
Per the article listed by Meta4 ("How Accurate Are..."), you probably only need "Relative" accuracy which can be obtained by placing a known length (ex. 2X4 Board) in your photo. Then you can take measurements within that photo based on the known length. If you want to dab in "Absolute" accuracy check out Jim Crume's "GIS Mapping: Step by Step Guide (Survey Mapping Made Simple)". Jim lays out a plan to use a handheld GPS equipment($600) versus the more accurate and expensive ($2000) equipment to record GPS points for accuracy within 1 to 3 feet.
Hope this helps.

 

[David_Cambridge]

Excellent article - thanks

 

[Aerial Imaging]

We're a landscaping company considering using a drone to measure sites for estimating. Our main focus is to generate orthomaps accurate to within 6", with mapping topography being second priority. What will it take to obtain this level of accuracy? Do we need to use GCPs? If yes, what level/type of GPS sensor will we need to establish the positions of the GCPs? I'm assuming a smartphone's built-in GPS isn't accurate enough. Or will a drone's built-in GPS without RTK/PPK provide accurate imagery geotags without GCPs?

As you've maybe guessed already, I'm totally new to drone mapping so I'm looking for beginner-level advice here.

for that kind of accuracy you need RTK and lesser then that you can use a P4 make sure its a The 1-inch high-resolution image sensor combined with the mechanical shutter then use drone deploy for software or a 3rd party 3D Software is what we sometime use for sand ,gravel rock piles this ables the customer to measure in metric tones for his monthly inventory and its also used in mapping we do top to side @240 Agl preferably but can be done at 200 save on flight time (Batteries)