Projectiles as large as space vehicle and as small as cannon projectile have some way to communicate with their ground station or launcher. Presented is a simple way to generate a modified polar coordinate in space. A projectile can sense its position in the spatial coordinate very easily.
Ming-Wen Chang, Ming-Wen Chang,
"Reticule Scanned And Pulse Modulated Laser Beam Spatial Coordinate System Design", Proc. SPIE 0813, Optics and the Information Age, (1 January 1987); doi: 10.1117/12.967171; https://doi.org/10.1117/12.967171