What Makes A3 Accurate?
A3's wide field of view, high resolution and multi-directional imagery, in addition to robust block adjustment algorithms, generate highly accurate photogrammetric mapping products even without Ground Control Points.
The following table presents typical accuracy analysis carried out over a test field in three different flights:
| Flight Mission | Altitude (feet) | Area (sq. km) | GSD (m) | GCP/ChP | RMSx (m) | RMSy (m) | RMSz (m) |
|---|---|---|---|---|---|---|---|
| Case 1 | 8500 | 100 | 0.08 | 16/22 | 0.06 | 0.08 | 0.10 |
| Case 2 | 12000 | 195 | 0.11 | 0/22 | 0.26 | 0.19 | 0.26 |
| 12000 | 195 | 0.11 | 11/11 | 0.19 | 0.11 | 0.23 | |
| Case 3 | 28000 | 247 | 0.26 | 0/27 | 0.54 | 0.44 | 0.47 |
| 28000 | 247 | 0.26 | 11/14 | 0.21 | 0.35 | 0.44 |
GCP=0 - no GCPs were used
Super Large Format Enabling Accurate Arial Triangulation
The A3 camera's extremely wide field of view provides an optimal base ratio as well as multiple image overlapping - ensuring high accuracy results in aerial triangulation.
Block Adjustment Using Millions of Tie Points
A3’s processing system is unique in its ability to automatically extract and match millions of tie-points in any given block size, resulting in:
- Robust bundle adjustment
- Excellent photogrammetric accuracy for all frames (including oblique images)
- Direct geo-referencing without ground control and IMU's
Multi-Directional Images
The A3's rotating camera design captures each point numerous times from different angles allowing:
- Exceptionally redundant and computationally stable automatic processing
- Multi-ray photogrammetry enabling highly accurate bundles, DEM and DSM
High Resolution Imagery
The A3 system’s long focal length optics capture high-resolution imagery, contributing to accuracy by:
- Increasing the accuracy of the automatic matching process
- Enabling collection of tie points in areas that would look uniform in lower resolution
