Proceedings of the Workshop - United Nations Office for Outer ...

EXPANDING GLOBAL NAVIGATION SERVICES 171InterferenceIn spite o f the right o f a State to adopt thecourse which it considers best suited to theexigencies o f its security and to themaintenance o f its integrity, the deliberateand unannounced denial o f service over aselected area could be a breach o f theprinciple o f non-discrimination, a violation o fthe Trail Smelter principle and o f the doctrineo f reliance.88Interference is an issue closely linked to availability andcontinuity of the GNSS signal. Indeed the service to beprovided must to the extent possible be free of anyharmful interference. Interference from the perspectiveof GNSS is also closely linked to accuracy of theprimary signals.Interference may be categorised as intentional andunintentional interference. Deliberate interference is themost essential issue. To the extent possible thediscussion will be limited to intentional interference,also known as jamming.The enormous accuracy of GPS, GLONASS, andas augmented by secondary systems as EGNOS,WAAS and MSAS has been of serious concern to themilitary. National security and the integrity of the statecould be seriously affected through the use of theaccurate systems as a weapon against any other states.The Gulf War and the Kosovo Crisis have shown whatpowerful tools satellite navigation systems are.Thus, one does not expect providers of the signalsto remain unconcerned about their security and remainsitting ducks. On the other hand, the provider or anyother state for that matter is legally not left unrestrainedto interfere deliberately with reception of GPS,GLONASS or any other satellite navigation signal.Moreover, international law limits the freedom ofstates to act when their acts could potentially causedamage to other states. This may be seen as preventiveworking of the doctrine of liability, something concededas being one of the main objectives of the tort law indomestic law89.The Trail Smelter Principle: sic utere tuout alienum non laedas90International law recognises the freedom of the state to,within its territory, act as it wishes, subject obviouslyto the law. The sovereign right of states to operatewithin the territories to protect the territory and thecitizens of the state is a jealously guarded right.Sovereignty, as reiterated in a number of arbitralawards and court judgements, signifies independence toexercise, to the exclusion of others, the functions of astate91. Furthermore, "[t]he right of a State to adopt thecourse which it considers best suited to the exigenciesof its security and to the maintenance of its integrity, isso essential a right that, in case of doubt, treatystipulations cannot be interpreted as limiting it ..."92.At the same time, however, international lawrecognises the right of states not to be injured by theacts of other states. The right of the one state to protectitself from danger coexists with the right of the otherstate not only to prevent danger but also not to besubjected to any harm by the other state in its action toprevent danger to its territory.Thus, to that initial right is a correlative duty: aduty resting on states not to cause harm or injury toanother state or its citizens. In other words, inasmuchas one has the right to enjoy and protect his property as84 See L Englard, The Philosophy o f Tort Law, 11 e t se q (l993).90 Henaku, op cit. note 3,19391 Island o f Palmas (1928).88 Henaku, op.cit note 3, pp. 190 - 198.92 The Wimbledon Case (1923). PCIJ Rep. Ser. A. No. 1Dissenting opinion by Anzilotti and Huber at 37.