Waypoint

Long before GPS, sailors crossing an ocean would aim for a series of known islands — not because they needed to stop at each one, but because each island was a checkable landmark that confirmed they were still on course. The islands were waypoints: intermediate goals that made an overwhelming journey tractable.

The concept transferred directly into robotics. A waypoint is a specific pose — position, and sometimes orientation — that a robot must pass through on the way to its destination.

Why waypoints instead of just a goal?

A single destination might be reachable by many routes, some of which pass through dangerous or restricted areas. Waypoints let an operator or planner constrain the path — not just where to end up, but roughly how to get there. A hospital delivery robot might be told: go to waypoint A (lift lobby), then waypoint B (corridor junction), then deliver to Room 412. The waypoints encode implicit knowledge about the building — which corridors are normally clear, which routes avoid ICU disturbance — that a pure end-point planner couldn't deduce from the map alone.

Waypoints also make progress observable. Instead of "the robot is somewhere between start and end," an operator can see "the robot has passed waypoints 1 through 4 and is heading to waypoint 5." For fault detection, this is enormously useful.

Waypoints in autonomous vehicles and drones

DJI drone mission planning apps (Waypoints missions) let you place a sequence of GPS coordinates on a satellite map, specify the altitude and action at each point (photograph, hover, circle), and launch the drone to execute autonomously. The waypoints encode the full mission intent. The drone's onboard planner handles low-level obstacle avoidance between waypoints.

Self-driving vehicle research platforms like Apollo (Baidu) and Autoware use GPS waypoint sequences pre-recorded by a human driver to define a nominal route, then add real-time perception and local planning on top.

Waypoints are not trajectories

A waypoint says "be here." It doesn't say when, how fast, or by what exact path. Converting a list of waypoints into a time-stamped, physically executable trajectory is a separate planning step. The two are often confused, but the waypoint is just a checkpoint — a spatial constraint. Everything else has to be filled in by the planner.

The word "waypoint" comes from maritime and aviation navigation, where it described fixed coordinates used to mark a route across featureless ocean or sky — and its meaning transferred to robotics almost unchanged.