tar is intended to operate in conjunction with existing terrestrial networks through gateways. These consist of equipment which interface signals from a Globalstar user to a local cellular network.. Globalstar will be offering a single world-wide communications solution for voice and data. Digital data can be transmitted up to 2,400 bit/s and position location services with better than 300 metre accuracy should be available nearly everywhere. Other services will include global paging, messaging, and international roaming.Unlike Iridium , Globastar satellites are trapezoidal in shape , which also allows many of them to fit on one launch vehicle . They are lighter than their Iridium counter parts , and weigh only 450 Kg . However , they have a relatively high orbit of 1414 Km . This allows each satellite to cover a greater distance on earth .Hence less satellites are needed . The total cost of the Globastar project is US $ 2,600 million .Table : summary of the major satellite systems .System nameIridiumGlobastarEllipsatOdyssey AriesInmarsatStart of service199819992000200020012001system cost US $ 4.4 billion$2.6 billion$1.1 billion$1.8 billion$2.0billion$ 1.2billionmobile terminal cost$2500$750-$2500N.A.$400N.A.N.A.Air time chargeper minute$3.oo$0.55$0.50.65N.A.N.A.orbit , Km78014008040910014503600satellite lifetime,years5-87.55-71066-7Number of satellites66 +6 spare48 +8 spare14 +2 spare12 +3 spare48 +6 spare24 + 2 sparePrimary servicesVoice, data , faxVoice, data , faxVoice, data , faxVoice, data , faxVoice, data , faxVoice, data , faxInvestorsMotorolaQualcomL3communicationTRWTeleglobeNokiaconsortium of 45 nations ConclusionDespite impediments and problems , LEOS still have many advantages over GEOS . Most important of which they are not confined by ground coverage of cellular phone relays , allowing people to communicate anywhere at any time . In the near future most human communication will be made through low earth orbiting s...
