SpacePositioning
Why IMU/GNSS matters in airborne mapping
Understanding the navigation component behind a georeferenced LiDAR point cloud.
Position alone is not enough
An aircraft moves and rotates while a laser scanner collects measurements. GNSS provides position information, and the inertial measurement unit helps describe motion and orientation. Together, their observations support the trajectory used to place laser measurements in the survey reference frame. A strong scanner cannot compensate for an unsuitable or poorly calibrated navigation installation.
Specify the exact navigation unit
Applanix AP20 and AP60 options are available through SpaceChamps, with the final selection depending on the complete survey configuration. Model names deserve care: AP60 and AP+60 should not be treated as interchangeable labels. RIEGL lists AP+60 and AP+50 among examples for its VQX-1 pod; that does not establish compatibility for every other unit or installation.
Integration needs measured geometry
The antenna, inertial sensor and laser have different physical locations. Their offsets and alignment must be measured, documented and handled consistently in processing. Timing errors or incorrect offsets can create systematic displacement even when individual devices appear to operate normally. A repeatable installation and a documented calibration procedure are therefore central to quality assurance.
Ask for evidence at delivery
The processing record should identify the navigation hardware, software version, correction method, reference frame and relevant quality indicators. Independent checkpoints provide a separate test of the resulting mapping. If a corridor includes difficult GNSS conditions, the survey plan should explain how those periods will be reviewed and what would trigger additional acquisition. SpaceChamps can scope the navigation and validation workflow alongside the required mapping products.