Global Navigation Satellite Systems (GNSS) are widely employed in safety-critical applications such as intelligent transportation systems, autonomous vehicles, and unmanned platforms. Despite their extensive adoption, civilian GNSS receivers remain highly vulnerable to spoofing attacks, in which counterfeit signals are transmitted to manipulate the position, velocity, and timing estimates of a victim receiver. Depending on the level of temporal alignment between genuine and counterfeit signals, GNSS spoofing attacks can be broadly classified into asynchronous spoofing, synchronous spoofing, and meaconing. From an adversarial perspective, the complexity of execution varies significantly across these categories. Asynchronous attacks and simple meaconing are becoming increasingly accessible due to the proliferation of low-cost Commercial Off-The-Shelf (COTS) Software-Defined Radios (SDRs), allowing even non-expert actors to disrupt navigation services.