A new system stops a drone when it tries to leave a protected area. It first checks the drone’s GPS position against a GoolRC S116 quadrotor’s keep‑inside zone. A lightweight Haversine formula calculates the great‑circle distance to that boundary in real time. Inside a 1 km warning zone the platform decelerates and lowers itself by following a piecewise‑linear speed and altitude law. When the drone reaches the boundary it comes to a full stop. If the drone moves past the boundary, a HackRF One SDR launches band‑limited noise on the 2.4 GHz control link. The whole process takes about 1 s from detecting the violation to stopping or jamming.

The algorithm uses two thresholds: a warning distance (1 km) and a shutdown distance (0 km). Between these distances the command speed drops linearly from the cruising speed to zero, and the same linear descent is applied to altitude. Mathematical analysis shows that for any initial speed and altitude the vehicle will reach zero speed and zero altitude exactly when it reaches the boundary. Simulation and field tests confirm this overshoot‑free, guaranteed shutdown.

In the field, 48 out of 50 trials successfully cut off the drone’s link within a 50 m radius of the border. The only failure occurred when the SDR was turned off, thereby proving the jamming only activates inside the intended zone. The controller also works for cruising speeds from 5 to 50 m/s and altitudes up to 100 ft.

Compared with a standard PID controller, the new linear law has three advantages. It guarantees convergence without any parameter tuning, it runs with constant‑time complexity, and it avoids the mild oscillations that PID shows near the warning threshold.

Limitations remain. The system relies on a Wi‑Fi telemetry link that limits the operational range to about 1 km when the line of sight is clear. The GPS module updates only once per second, which accounts for most of the 1 s total enforcement latency. Other constraints include regulatory limits on radio jamming and the need for future work on multi‑UAV detection, long‑range telemetry, higher‑rate GNSS, and in‑flight validation of the speed/altitude control on hardware.