Ground Control Point
نقطة التحكم الأرضي
Also known as: GCP
A ground control point (GCP) is a surveyed marker visible from the air whose exact coordinates are measured with survey-grade GNSS. Photogrammetry software uses GCPs to anchor the photo block to the real-world coordinate system, eliminating drift accumulated by IMU integration. Without RTK, you typically need 5-9 GCPs distributed across…
Definition
A ground control point (GCP) is a surveyed marker visible from the air whose exact coordinates are measured with survey-grade GNSS. Photogrammetry software uses GCPs to anchor the photo block to the real-world coordinate system, eliminating drift accumulated by IMU integration. Without RTK, you typically need 5-9 GCPs distributed across the site; with RTK, 2-3 check points suffice for accuracy verification. FI Tech standardizes on 60 cm checkerboard panels for GCPs on Saudi sites — the contrast survives full midday sun without saturating sensors. Each GCP is geo-tagged in our project database for repeat flights to maintain ±2 cm vertical reproducibility week over week.
