Executive Summary
Lithuania's defensive geometry has a hole. Ground-based radar misses low-flying drones because forests, hills, and the curvature of the earth block line-of-sight under about 1,000 metres. Russia and Belarus exploit this gap daily: FPV drones below 150 metres, Orlan reconnaissance drones at 200-1,000 metres, Geran-2 cruise drones at 60-500 metres, plus hybrid balloons and Gerbera decoys probing the radar picture. Lithuania's incoming kinetic stack — 48 Merops AS-3 interceptors (April 2026), €214M of AIM-9X missiles, additional NASAMS, and the Bundeswehr Panzerbrigade 45 with Skyranger 30 — needs upstream cueing; Ukrainian operational data shows kinetic effectors waste 30-50% of shots on decoys when fired without sensor fusion. A drone tethered to a vehicle by a power-and-data cable, hovering at 100-200 metres, sees what ground radar cannot, and runs for days at roughly €13-14 per flight-hour — a few hundred times cheaper than a manned helicopter. This is the low-altitude complement to Poland's Barbara aerostat ($960M, ~4,000 metres, 226 km horizon, fielding 2026); it does not replace Barbara and does not see Geran-3 jet variants cruising at 9,000 metres. Honest geometry: 25 vehicle-mounted nodes at 10-15 km sensor radius cover 12-27% of national territory — point defence of named sites plus mobile reinforcement of the 952 km eastern border, not blanket coverage. Architecture must be mobile-only: Russia produces around 75,000 guided bombs (KABs) a year and the UMPB-5R reaches 130-200 km from Belarusian airspace, so any fixed tower becomes a target. The recommended next step is a Phase 1 demonstrator of three vehicle-mounted systems at Klaipėda LNG, Vilnius, and Šiauliai, costed at €12-18M, as the operational test of the September 2025 Šakalienė amendments to the Law on Aviation. Final platform selection, network size, and integration choices are decisions for the Ministry of National Defence and the FY26 budget cycle.
The Problem
Russia and Belarus run continuous low-altitude pressure against Lithuanian and Baltic airspace. The threat bands are documented: Geran-2 baseline cruise at 60-500 metres and 185 km/h; Geran-3 jet variant at 550-600 km/h and 9,000 metres ceiling with up to 300 kg warhead (United24, 423grifony.com); Geran-5 deployed January 2026 (United24); Gerbera decoys probing radar signatures; Orlan-10, ZALA, and Supercam reconnaissance drones below 1,000 metres; hybrid balloons launched from Belarus. Tatarigami reporting confirms Geran-3 cruises at 50-150 metres terrain-following over Belarus before climbing — meaning low-altitude detection matters even for threats that finish at high altitude. Ukrainian operational data shows Russia launches 100-200 one-way attack drones daily with peaks above 800.
Lithuania's primary air surveillance is ground-based Giraffe AMB radar feeding NASAMS, supplemented by NATO AWACS tasking. Ground radar suffers documented line-of-sight masking in forested areas and against targets below 60 metres; AWACS coverage is non-persistent and shared across the Baltic theatre. There is no indigenous persistent low-altitude sensor. Poland is fielding the Barbara aerostat at roughly 4,000 metres under a $960M Foreign Military Sales package (Army Recognition 2026), giving a 226 km radio horizon for cruise-missile detection along the NATO eastern border; Lithuania has no equivalent and no announced plan for one. Tethered platforms address only the low-altitude band 50-500 metres — they do not replicate Barbara-class horizon, and they do not cover Geran-3 or Geran-5 jet variants which cruise 30-45 times above the tether ceiling.
Without action: Without upstream low-altitude cueing, Lithuania's 2026 kinetic stack engages ambiguous tracks and burns expensive interceptors on decoys — Ukrainian data suggests 30-50% of shots are wasted under those conditions, against a Lithuanian FY26 anti-drone budget of around €145M. The September 2025 Šakalienė amendments authorising immediate engagement of airspace violations remain operationally empty in the band where most of the actual threats fly.
Lithuanian Context
Lithuania has 679 km of border with Belarus and 273 km with Kaliningrad — 952 km of hostile axis — with Vilnius 35 km from Belarusian territory and 33% national forest cover creating exactly the low-altitude radar dead zones that tethered platforms are designed to fill. Honest geometry: 25 vehicle-mounted nodes at 10 km sensor radius cover about 12% of the country's 65,300 km² (7,854 km²); at 15 km radius about 27% (17,671 km²). Continuous border-wide coverage at hand-off geometry would require 32-48 nodes — beyond the 25-30 node envelope. Mission scope is therefore point defence of named critical sites (Klaipėda LNG, Vilnius, Šiauliai Air Base, LitPol Link, NordBalt landing, Kruonis pumped storage, Kaunas military district) plus intelligence-tasked mobile reinforcement of border sectors, not blanket national coverage. Phase 1 demonstrator at €12-18M for Klaipėda LNG, Vilnius, and Šiauliai is the operational test of the September 23 2025 Šakalienė amendments to the Law on Aviation — airspace authority only, distinct from broader use-of-force law — and a yes-or-no decision the Ministry of National Defence can champion in one budget cycle. France appears in this initiative as an industrial supplier (Elistair) only; Lithuania, Latvia, and Estonia are absent from the Macron Île Longue partner list announced 2 March 2026 and from the Treaty of Nancy follow-on at Gdansk 20 April 2026 (signed PL-FR 9 May 2025) — absent from the named list, not explicitly excluded — so the strategic frame here is Polish Barbara, not the French extended-deterrence umbrella.