Receiver lock on a spurious carrier

# Description

The lock of the spacecraft receiver or of the ground station with a continuous wave or with the obtained DSSS sequence can be a threat. Increasing the power is the only way to unlock the receiver, or it unlocks when the spacecraft moves out of LOS with the attacker GS. The attack depends on the receiver and on the system dynamic, that causes the doppler effect and requires a major bandwidth. A possible mitigation is the cryptographic DSSS sequence.(Citation: European Space Agency)