Time-to-collision between own ship and target based on relative-position vector. Used inside autonomous collision-avoidance algorithms.
Formula
$$ TTC = \frac{\text{Range}}{\text{Closing rate}} $$
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $Range$ | Current range | nm | radar |
| $Closing rate$ | Rate of approach | kn | ARPA |
| $TTC$ | Time to collision | min | result |
Sources
- COLREGS Rules 7–8.