What Is GPS Spoofing and How It Disrupted Flights in Delhi?

Delhi’s Indira Gandhi International Airport (IGIA) has faced unprecedented GPS spoofing incidents, leading to diversions and congestion during critical operating windows. The disruption coincides with an Instrument Landing System (ILS) upgrade on the primary runway, forcing greater reliance on satellite-derived navigation.

What Is GPS Spoofing?

GPS spoofing is the transmission of counterfeit satellite signals that mislead receivers about position, velocity, or time. Unlike jamming, which blocks signals, spoofing feeds plausible but false coordinates. Flight management systems and avionics that trust these inputs can drift from the real flight path, triggering alerts or forcing crews to abandon satellite-based approaches.

Why Were Delhi Flights Hit?

Operational complexity at IGIA increases when easterly winds require landings from the Dwarka side and departures toward Vasant Kunj. During such configurations, traffic density grows and spacing margins tighten. Spoofed signals reportedly appeared as far as 60 nautical miles from the airport, degrading the reliability of arrival procedures and prompting go-arounds or diversions to secondary airports such as Jaipur. With the hub handling up to 1,550 daily movements, even short-lived navigation anomalies ripple into system-wide delays.

ILS Upgrade and RNP Reliance

IGIA’s main runway 10/28 is temporarily without ILS during a Category III upgrade that will ultimately enable low-visibility landings from both ends. In the interim, aircraft depend more on Required Navigation Performance (RNP) procedures, which are GPS-dependent. When spoofing corrupts satellite inputs, RNP approaches become unstable or invalid, leaving pilots to revert to conventional navaids, visual cues, or hold/alternate strategies until integrity is restored.

Exam Oriented Facts

• Spoofing injects false GPS data; jamming only blocks signals.
• RNP approaches require verified satellite accuracy and integrity.
• ILS Cat III supports operations in dense fog with very low minima.
• Spoofing has been documented near conflict zones; Delhi reports are a first for IGIA.

Safety Measures and Next Steps

Pilots are being briefed via ATIS to cross-check raw data, monitor RAIM/GBAS integrity, and switch to conventional procedures when anomalies arise. Airlines are flagging spoofing hotspots and tightening diversion triggers. Airport and regulators are expediting ILS reinstatement on 10/28 to reduce GPS dependency during poor visibility. Once the Cat III system is operational, Delhi’s resilience to both winter fog and satellite signal threats will significantly improve.