Network Corrections

ON THIS PAGE

1. Overview
2. What you'll achieve
3. How it works
4. Before you begin
5. The workflow
6. Achievable accuracy
7. Limitations
8. FAQ
   
   

Overview

Getting high-accuracy geotags from a flight normally means using a base station in the field or downloading CORS data and processing it. Both add hardware dependencies and limitations, and both fail when a base is left behind, a battery dies, or no reference station is within range.

Network Corrections removes that dependency: our software corrects the geotags from your  flight automatically, using a worldwide Global Navigation Satellite System (GNSS) correction network, with no base station or CORS data required.

What this means:

1. Never re-fly a site because of a base station failure
2. Get 100% coverage to unlock remote and fast-deploy projects
3. Skip the base-station setup, run faster and simpler surveys

What you'll achieve

Corrected geotags for every image in your flight, with a per-image accuracy estimate — ready to use as input for map processing. 

You upload only your flight data; Wingtra's software applies the GNSS corrections and returns a corrected CSVor EXIF  geotags, plus a correction report on the files page.

How it works?

Your WingtraRAY records raw GNSS data throughout the flight, exactly as it does for any mission. When you upload the flight and select Network Corrections, WingtraCLOUD sends the flight's GNSS observations to a global correction network, retrieves the correction data, and computes a corrected position for each image geotag — you do not upload any base station or CORS files.

The Workflow

TL;DR

Fly your project as usual, no need for GNSS data retrieval and select Network Corrections at the geotagging Corrections step for "Data Source"

Full Workflow

Step 0) - Update your software and firmware to the latest versions

Step 1) - Flight planning -> Same as before

Step 2) - Flying -> Same as before (just without a base)

Step 3) - Geotagging -> Drag your project folder in and simply select Network Corrections

 Geotag Processing Screen

Step 4) - Download / save Geotags -> Same as before

Step 5) - Photogrammetric Processing -> Same as before

All that's changed is the necessity to collect GNSS RINEX/.t0X files from a base receiver or CORS network.

For more information on the geotagging workflows and steps, see here:
Wingtra Geotagging

Achievable Map Accuracy

The following is based on testing performed in the US and Switzerland:

< 0.1 USft (3cm) Hz + V -> With GCPs

PRELIMINARY*
< 0.15 USft (4.5cm) Hz and <0.3 USft (9cm) -> Without GCPs

*Accuracy without GCPs depends greatly on coordinate system transformation accuracy, GNSS corrections, IMU data and other factors which would be mitigated largely in the map processing with good GCPs. Further testing and work is ongoing to improve and validate the achievable accuracy. This preliminary value is to serve as indicative.

FAQ

Q: Do I need to record from a base station or pull data from a CORS to use?
A: No -> Network Corrections just the needs the navigation

Q: Do I need internet to geotag with Network Corrections?
A: Yes -> Navigation data is sent to Trimble's PP-RTX service for GNSS correction

Q: Is my sensitive image data sent to another online server / web service to process?
A: For pure geotagging, no. 

Q: What is the minimum flight time required?
A: Recommended flight duration is around 10-15 minutes (FAST regions defined by Trimble's PP-RTX as USA, Brazil and Europe use regional modelling and faster convergence times - this leads to reduced flight time)

Q: Is there any usage costs or limitations?
A: No - Network Corrections is included in all PRO and UNLIMITED plans without usage limitations 

Q: What errors am I likely to see if I don't use GCPs?
A: Based on  initial testing, the error mostly results in a vertical offset. Horizontal errors on geotag locations and orientations are largely mitigated due to high overlap. The relative geometry of the model (with RAY + SURVEY61) has been shown to be good that an alignment to a previous 3D map may be possible (e.g. C2C registration).