OpenGCP: An open-source smart Ground Control Point (GCP) for drone mapping.

The OpenGCP is the perfect low-cost addition to your drone mapping workflow. Our GCP rivals the performance of the leading competitor at a fraction of the cost. We aim to make drone mapping with high accuracy accessible to the average drone pilot without the overhead costs of commercial smart GCP’s.

Compatible with all drones
Compatible with all photogrammetry engines
Dual-frequency, multi-constellation GNSS localization
PPK-enabled
USB-C interface -or- microSD card reader
No data signal required
No subscription required
Powered by AA-batteries (8+ hours battery life)

OpenGCP runs on Python and C++. Our software is open-source and available on our GitHub page [coming soon].

Feature	Commercial Smart GCP	OpenGCP

Global Accuracy¹	15-30mm	10 – 100mm
Post-flight Time to Corrections²	5 min – 24 hours	1 min – 24 hours
Unit Price (Per GCP)	$1000 USD	$589 USD
Annual Subscription Price	$999 USD / year	$0 USD / year
User-Modifiable Behavior	No	Yes

Notes:

Circular Error Probable (CEP) accuracy is highly dependent on duration of GNSS data collected, kinematic correction using RTK or PPK methods, and baseline distance between the smart GCP (“rover”) and base station. In most situations, the two products are approximately equivalent.
OpenGCP may be used immediately following the flight without correction; however, accuracy will be at top end of the range. The time required to obtain corrections depends on how frequently the chosen CORS station publishes its correction data. 24 hours is the worst-case scenario.

OpenGCP’s secret ingredient is the venerable ZED-F9P Precision GNSS Module from u-blox. The F9P receives position data from several constellations with high accuracy and allows further corrections from real time (RTK) or non-real time (PPK) sources. OpenGCP is capable of providing raw data to the photogrammetry engine, and its performance is improved tenfold with PPK correction from the many Government-funded CORS stations.

OpenGCP OpenGCP

How to use OpenGCP:

Arrive at the job site.
Put the OpenGCP on the ground and turn it on.
[Repeat step 2 for each OpenGCP.]
Fly the mission.
Pick up the OpenGCPs and turn them off.
[Repeat step 5 for each OpenGCP.]
Plug in each OpenGCP to a computer via USB-C and run the automated script.
[Optional] Run the automated CORS PPK correction algorithm on the OpenGCP data.
Run your normal mapping engine using the [corrected] OpenGCP data to correct the imagery.
1. OpenGCP data may be used as Control Points or Check Points at the user’s discretion.
Evaluate the results of your corrected map to determine suitability.
Deliver the corrected map to the customer.
Profit.

All units are made to order. Expect 2-4 weeks until delivery.

[COMING SOON] Visit our GitHub page.

FAQ

Q: How do I know if OpenGCP is right for me?

A: There are only two pre-requisites to be an OpenGCP user.

1. You must want to improve your drone map location accuracy inexpensively.

2. You should have, or be willing to get, some familiarity running Python scripts, either via command-line interface (CLI) or an IDE.

If you use WebODM, then OpenGCP will be no problem for you.

Q: What mapping software is this compatible with?

A: All of them! We built it with WebODM users in mind, but the GCP data file can be reformatted to any mapping engine’s format. We will slowly introduce more tools to automate this process as the need arises.

Q: Am I required to use PPK corrections?

A: Not at all; however, the location accuracy will either be far lower, or take far longer to survey-in, than if you use PPK. Our automated tools strive to make this process as painless as possible. The main drawback is waiting for CORS stations to publish their correction data.

Q: There are no CORS stations near me; what should I do?

A: Same here. Even if your CORS data does not provide tremendous improvements to location accuracy, every little bit counts. Even an un-corrected data log will eventually converge on centimeter-level accuracy; PPK corrections just reduce the time required. Our software suite helps you run tests to determine the best solution in your area.

Bonus: Stay tuned for our future product, OpenCORS.

Q: Is OpenGCP better than getting an RTK or PPK drone?
A: An RTK/PPK drone is great at improving your drone’s awareness of its location at each photo snap, but there are still small errors in the pan/tilt/roll/zoom of the camera that can translate to 20cm or more error in the images’ location accuracy–especially near the edges. For that reason, we suggest that the drone mapping workflow also include GCPs to georeference the pixels in the image. So, it is not a matter of better or worse; rather, the two GNSS correction approaches (RTK/PPK for the drone, and GCPs in the image) complement one another to give you the highest accuracy map available.

Q: Is OpenGCP compatible with RTK?

A: Not out-of-the-box. The GNSS receiver (ZED-F9P) is RTK-capable, but we did not make provisions for this in our base model. If you would like to take on the project of “upgrading” OpenGCP to include RTK compatibility, we would love to support you and share your instructions on our GitHub page. Depending how strong the demand is, we might include this as a product option in the future.

Q: Will OpenGCP eliminate my need to integrate with a survey team?

A: We will never claim to match the accuracy and reliability of a professional surveyor; however, we believe that OpenGCP will absolutely enhance the accuracy of your mapping, either as a complement to the GCP’s set by the surveyors, or as standalone corrections. More GCPs is (almost) always better, and OpenGCP offers you a fast, low-cost method to increase the number of GCPs without spending additional time on-site. If your drone is RTK or PPK equipped, then you have a winning combination that rivals a traditional surveyor.

Alternative to Propeller AeroPoints.

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