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Geoinformatics_06-2009
article four potential recommendations have been made to prevent brownouts : 1 reactivate retired gps satellites that are still operating 2 speed up gps iiia development 3 develop a simplified gps iiia design in parallel that can be built and launched quickly 4 extend the gps iif production line. specialists warn against this option as the iif design is rather old and not well suited to modern needs. an example is the lack of both the military (m) signal as well as the l1c signal on the block iif satellites compass on april 15 china launched a second beidou / compass g2 satellite to a geostationary orbit. the satellite became operational on april 20. the first second-generation satellite was launched into medium orbit in april 2007. china claims that it may add up to 10 more satellites by the end of 2010 and plans to put up the full 30-satellite constellation by the end of 2015. the open compass service is supposed to be able to provide positioning accuracy of up to 10 meters. the interoperability of compass with other gnss such as gps, galileo and glonass remains an open question although officials still offer assurance that interoperability is a key element of compass. in particular, the conflict with galileo is still at an impasse. furthermore, no compass interface control document has been published so far by the chinese authorities, making it difficult for hardware manufacturers to start chip design. qzss pattern (source: www.jaxa.jp) galileo not much new on the technical side for galileo, but more so on the organizational side. norway, which is not an eu member, has decided to participate in the galileo project at a cost of approximately 63 million euros over the next five years. norway was involved in the early design phase of galileo as well, resulting in the current orbits among other things. originally the design called for a combination with geostationary orbits, but after testing in norway this was found undesirable for higher latitudes. glonass the future for glonass seems bright, at least in russia. at the moment of writing, the glonass constellation consists of 18 active satellites (and 2 in maintenance). the deputy head of the glonass mission control center, sergey revnivykh, said that russia plans to launch three more glonass-m satellites in september and another three in december this year. the complete constellation of 24 is expected to be achieved by the end of 2010 allowing for the breakdown of a number of satellites over the coming period. for 2010 a test flight with the new glonass-k satellite is planned. this satellite will have the new l3 signal that is compatible with the gps and galileo signals, employing cdma rather than fdma modulation technique. the new signal would supposedly give glonass a performance that is comparable with gps and galileo by 2011. russia plans to speed up the use of glonass over gps in its own country by an alleged raising of gps end product import duties to russia to at least 25% while also submitting a proposal for reducing the import duties on glonass electronic components to zero. qzss the japanese qzss wide area augmentation system is now in the building phase with the first of the three satellites being assembled. the launch of the first satellite is projected for the summer of 2010 followed by a three-month test period. after the test period the japanese government will decide on the launch of the other two satellites. the qzss satellites are unique in that they do not orbit the earth as gps, galileo and glonass do. neither are they in a geostationary orbit. rather, they make figure of eight patterns around the equator over japan. in contrast to compass, there is an interface document for qzss making it possible for manufacturers to start building hardware and software upgrades so that users can begin using the augmentation signals when they become available. eloran the report from the us independent assesment team (iat) on eloran has unanimously recommended that the eloran upgrade be completed and that eloran should be the national backup to gps for 20 years. in the meanwhile it is proposed to keep on maintaining the current loran-c network. huibert-jan lekkerkerk hlekkerkerk@geoinformatics.com is project manager at idsw and a freelance writer and trainer. this article reflects his personal opinion. s latest news? visit www.geoinformatics.com 23 september 2009
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