Methods and limitations
Understand the geometric visibility model and specification provenance.
Each terrain triangle is sampled at its centroid. A mesh bounding-volume hierarchy accelerates exact ray/triangle obstruction tests from the antenna. A small scale-dependent contact tolerance excludes numerical origin and target contacts. Minimum/maximum slant ranges and horizontal/vertical scan angles define the envelope.
Vector loss is 100 × (1 − abs(dot(unitLOS, unitMovement))). Zero means the assumed displacement lies along the line of sight; 100% means it is perpendicular. Surface-normal mode uses the full normalized triangle normal. Surface-azimuth mode uses its normalized horizontal projection (normal.x, normal.y, 0) while retaining the full 3D line-of-sight direction in the dot product. Both are insensitive to the normal's sign. A flat face has no horizontal normal component, so surface-azimuth vector loss is unavailable rather than zero or 100%. User-defined azimuth uses (sin(azimuth) cos(plunge), cos(azimuth) cos(plunge), -sin(plunge)) in east/north/up coordinates.
Nominal pixel width is slant distance × pixel size in degrees × π / 180. A 4.3 mrad angular specification gives 4.3 m at 1 km. Manufacturer milliradian values are converted without rounding the stored angle. Pixel spacing and independent spatial resolution are different specification types; oversampling does not establish finer resolving power.
This small-angle calculation does not project the pixel footprint onto the slope or model off-axis aperture response. Individual terrain triangles are not radar pixels. Visibility does not model atmosphere, reflectivity, coherence, displacement accuracy or actual detectable feature size. Coarse triangles may cross visible and obstructed areas; refine source geometry where small obstacles matter.
Source basis
The configuration catalogue records source URLs, revisions, verification dates and qualifications. Read these in Radar specifications… → Specification basis before using a preset. Unknown parameters remain blank instead of inheriting values from a different configuration.
Sources include IDS ArcSAR specifications, IDS FM EVO brochure, and GroundProbe's radar catalogue. The source basis describes the imported catalogue; it is not a promise that every manufacturer's current offering has been verified anew.