evidence: Ukraine's invisible battle to jam Russian weapons In the early days of the invasion of Ukraine, experts were surprised at how poorly the Russian army's electronic warfare units performed. But nearly 18 months later they are causing significant problems for Ukraine's counter-offensive. [...] Bryan Clark says Russia has managed to deploy hundreds of mobile electronic warfare units along the front line in an attempt to slow down Ukraine's counter-offensive. These range from GPS jammers to systems that suppress radar and prevent US aircraft identifying targets for Ukraine to attack.