# FOI publishes electromagnetic warfare primer for total defence

- Source: Nordic Defence Sector (https://nordicdefencesector.com)
- Canonical URL: https://nordicdefencesector.com/en/article/foi-publishes-electromagnetic-warfare-primer-for-total-defence
- Published: 2026-10-21
- Author: Daniel Trangeled
- Type: News · Section: Cyberspace · Country: sweden
- Language: en (original)
- Also available in: de (https://nordicdefencesector.com/de/article/foi-publishes-electromagnetic-warfare-primer-for-total-defence.md), dk (https://nordicdefencesector.com/dk/article/foi-publishes-electromagnetic-warfare-primer-for-total-defence.md), es (https://nordicdefencesector.com/es/article/foi-publishes-electromagnetic-warfare-primer-for-total-defence.md), fi (https://nordicdefencesector.com/fi/article/foi-publishes-electromagnetic-warfare-primer-for-total-defence.md), fr (https://nordicdefencesector.com/fr/article/foi-publishes-electromagnetic-warfare-primer-for-total-defence.md), it (https://nordicdefencesector.com/it/article/foi-publishes-electromagnetic-warfare-primer-for-total-defence.md), no (https://nordicdefencesector.com/no/article/foi-publishes-electromagnetic-warfare-primer-for-total-defence.md), pl (https://nordicdefencesector.com/pl/article/foi-publishes-electromagnetic-warfare-primer-for-total-defence.md), sv (https://nordicdefencesector.com/sv/article/foi-publishes-electromagnetic-warfare-primer-for-total-defence.md)
- Primary source: https://www.foi.se/rapporter/rapportsammanfattning.html?reportNo=FOI-R--5989--SE
- Tags: sweden, foi, electromagnetic warfare, foi informerar om, satellite, baltic sea, swedish defence research agency, total defence, nato, radar, satellite navigation, software-defined radio, jamming, hybrid warfare

> FOI has published a 132-page primer on electromagnetic warfare as training material for Sweden's total defence, covering jamming, spoofing and protective measures against radio, radar and satellite navigation threats. The report warns, among other things, that GPS jamming near Sweden and the Baltic Sea is an active form of hybrid warfare.

![Cover image of the 'FOI informerar om' publication about electromagnetic warfare](https://imagedelivery.net/XO8UY-c6-LfWgEjQsN8IQw/15a019e7-bf57-473d-d4af-7e76e0c74200/public)
*Cover image of the 'FOI informerar om' publication about electromagnetic warfare · FOI*

**The Swedish Defence Research Agency (FOI) [has published](https://www.foi.se/rapporter/rapportsammanfattning.html?reportNo=FOI-R--5989--SE) a 132-page introduction to electromagnetic warfare. It is intended as training material within Sweden’s total defence. The report, released in October, covers electromagnetic warfare against radio communications, radar, electro-optical and laser communication systems. It uses NATO’s division into support, attack and protective measures.**

The publication opens with an example from nature. A bat hunts using ultrasonic echolocation and can detect prey about five metres away. A moth can hear the bat’s calls from about 40 metres, which FOI compares to a radar warning receiver. Some moths also click to jam the bat’s sonar.

FOI states that jamming of satellite navigation signals is common far outside war zones. According to the report, jamming aimed at civilian activity occurs in Sweden and its neighbouring region. FOI calls this “an active example of hybrid warfare.” The interference has also been noted in the Baltic Sea, which FOI says can endanger civil shipping and aviation.

The report also highlights software-defined radio, which makes spoofing open satellite signals relatively easy. The same technology is cutting the cost of anti-jamming protection. Military systems of this kind can cost 50 times more than the receiver they protect. FOI notes that cheaper protection also makes precision weapons harder to counter with electromagnetic warfare.

The report is the latest in FOI’s “FOI informerar om” series. It follows a [guide](https://nordicdefencesector.com/en/article/swedish-defence-research-agency-publishes-nuclear-weapons-primer) on nuclear weapons published in September, previously reported by NDS.

## FAQ

**What does FOI's new electromagnetic warfare primer cover?**

FOI's 132-page report is training material for Sweden's total defence, covering electromagnetic warfare against radio communications, radar, electro-optical and laser communication systems. It applies NATO's division into support, attack and protective measures, and was released in October as part of the 'FOI informerar om' series. Last fact-checked: 2026-10-21.

**What example from nature does FOI use to introduce electromagnetic warfare concepts?**

The report opens with bats hunting via ultrasonic echolocation, detecting prey about five metres away, while moths can hear the bat's calls from roughly 40 metres. FOI compares this moth capability to a radar warning receiver, noting some moths also click to jam the bat's sonar. Last fact-checked: 2026-10-21.

**Why does FOI consider satellite navigation jamming a form of hybrid warfare?**

FOI states that jamming of civilian satellite navigation signals occurs in Sweden and its neighbouring region, including the Baltic Sea, which it calls 'an active example of hybrid warfare.' The agency warns this interference can endanger civil shipping and aviation far outside active war zones. Last fact-checked: 2026-10-21.

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