The International Telecommunications Union (ITU), International Maritime Organization (IMO) and International Civil Aviation Organization (ICAO) recently issued a joint statement urging “Protection of the Radio Navigation Satellite Service from Harmful Interference.”

All three organizations are United Nations agencies and have previously issued similar statements independently. This is the first time they have spoken on this in one voice.

In 2020, ICAO issued a letter to all member states urging them to “strengthen CNS systems resilience and mitigate interference to GNSS.” It contained 13 recommendations resulting from three different work streams within the organization. The last of the recommendations was “… to support the multi-disciplinary development of alternative positioning, navigation and timing (APNT) strategy and solutions to complement the use of GNSS in aviation in coordination with ICAO and airspace users.”

In 2021, IMO issued a circular on deliberate GNSS interference.. It called on nations to prevent interfering transmissions coming from their territories, issue warnings about known interference, and consider taking actions to prevent unauthorized interfering transmissions.

ITU issued a circular on “Prevention of harmful interference to Radio Navigation Satellite Service Receivers in the 1559 – 1610 MHz frequency band” in 2022. It emphasized that, according to ITU Radio Regulations, “All stations are forbidden to carry out unnecessary transmissions, or the transmission of superfluous signals, or the transmission of false or misleading signals…”

This ITU circular urged nations to “address the critical issue” by:

• Reinforcing navigation systems’ resilience to interference.
• Increasing collaboration between radio regulatory and enforcement authorities.
• Reinforcing civil-military coordination to address interference risks associated with RNSS testing and conflict zones.
•  Increase coordination between aviation, military and radio-regulatory authorities.
• Retain essential conventional navigation infrastructure for contingency support in case of RNSS outages and develop mitigation techniques for service loss.

A resolution by ITU’s 2023 World Radiocommunications Conference echoed similar themes. Still, it was criticized because its cautions and prohibitions came with the caveat, stating “…without prejudice to the right of administrations to deny access to the RNSS, for security or defense purposes.”

Many observers opined that there are few reasons for nations to interfere with GNSS other than security or defense concerns, which allowed malicious actors to have carte blanche. Furthermore, it was suggested that the resolution might have included language to ensure that security and defense-related disruptions do not extend beyond a nation’s borders or similar provisions.

While no specific events are cited in the statement as motivating its publication, the death on Christmas Day of thirty-nine people aboard an Azerbaijan Airlines flight could have been the reason. The aircraft was approaching a Russian airport during an intentional interference event and was apparently misidentified by Russian forces. It was subsequently damaged by ground fire and crash-landed in Kazakhstan.

The recent joint statement cites, among other international agreements and actions, the ITU Constitution, which says, “All stations, whatever their purpose, must be established and operated in such a manner as not to cause harmful interference to the radio services or communications of other Member States.”

The joint statement concludes with:

Therefore, ITU, ICAO and IMO jointly and urgently call on their respective Member States to:

• Protect the RNSS from transmissions that can adversely cause harmful interference, degrading, interrupting, or misleading signals used for civilian and humanitarian purposes.
• Reinforce the resilience of the systems that rely on RNSS for navigation, positioning, and timing in relation to this type of interference.
• Retain sufficient conventional navigation infrastructure for contingency support in case of RNSS outages and misleading signals, and develop mitigation techniques for loss of services.
• Increase collaboration between radio regulatory, civil aviation, maritime, defense and enforcement authorities.
• Report cases of harmful interference affecting RNSS to the appropriate telecommunication, aeronautical, and maritime authorities and the ITU Radiocommunications Bureau to enable the monitoring of the situation.

The United Nations and its agencies are collaborative bodies that operate by consensus and through the cooperation of members. As such, they have no ability to enforce standards or compel compliance with recommendations.

Read the joint statement here.

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