GPS system will greet new cycle on April 6 --
Global location system " clear " , can you speak new " Y2k " ?
After will passing on April 6, the whole world that the people often uses in daily life locates systematic GPS will greet new cycle. On the plenary meeting of safety of information of RSA United States that held in san Francisco recently, the expert is forecasted, old GPS system will produce the mistake of similar computer Y2k on April 6; More safe expert expresses, oneself won't enplane that day absolutely...
Why can GPS have " clear " phenomenon? What influence can this bring to us? Does the north of our country fight a system to whether also be put in this problem? How do scientists look, what solution is there? For this, reporter of daily of science and technology interviewed a the Chinese Academy of Sciences to concern an expert.
"Does GPS Zhou Shu retroflexion " be what?
According to the United States civil GPS serves interface committee (the announcement that CGSIC) issued recently, the whole Zhou Ji of GPS counts value general on April 6, 2019 at 24 o'clock by 1023 turn into 0, call GPS Zhou Shu to retroflexion. This means GPS week count to will greet new cycle.
Why can you appear such circumstance? "This must explain this phenomenon from the interface design of GPS system. " be engaged in north for a long time fighting the scientist that the job builds related navigation system, xu Ying of adviser of researcher of academy of news of empty day of Chinese Academy of Sciences, doctoral student says, GPS system regards a global navigation as system of fixed position time service, built system of oneself a time in the beginning of design, when calling GPS, and time of UTC of this start correspondence (between world universal time coordinated) on January 6, 1980 0 when. To achieve the goal of time service, criterion GPS system broadcasts to the user ceaselessly through navigation signal when the GPS of correspondence of current hour place, systematic design personnel is counted through Zhou Ji (the second inside WN) and week (TOW) will state current hour is apart from GPS jointly the time of initiative hour is wrong, combine bissextile second to get current UTC hour thereby, the time service that finish.
He Zhi force says engineer of academy of news of empty day of Chinese Academy of Sciences, because of many sided reason, at the beginning of GPS is being designed, design personnel used 10bit to come only token WN, bring about WN to be able to be in only 0, 1023 between circularly. When WN from 1023 turn into 0 when, can produce GPS Zhou Shu to retroflexion, appear the statement that meets new a week. 1024 weeks of correspondence arrive year going up is 19.7 years probably, the initiative hour from GPS system calculates case, appear last time GPS Zhou Shu retroflexions was on August 21, 1999, this solicit comments will be on April 6, 2019 very, will give at present on November 20, 2038 GPS Zhou Shu retroflexions.
"Make an example, because the child still exceeds several of 100 without study, his every frequency arrives 100 from 0 begin number, and press 10 into the computation regulation that make, 100 it is later 101, 200 it is later 201... with this analogize, and the child encounters 100 metropolises to return every time 0. This is similar to GPS Zhou Shu to retroflexion. " He Zhi force says.
What influence may bring?
"GPS receiver was not making the pretreatment case that GPS Zhou Shu retroflexions, before the output that brings about receiver time is returned. This may cause an effect to depending on any systems of GPS time service and application. " He Zhi force thinks, in civil aviaton domain, giving time base is to rely on satellitic navigation system to finish originally, the equipment of all automation is with this time serves as fiducial.
Accordingly, zhou Shu retroflexions the likelihood causes empty Guan Lei to amount to signal data disorder, can cause data to interrupt, target flight path and plan are not relevant wait for a problem.
At the same time the information exchange between weather equipment also can jump to change and cannot finish weather news automatically to be opposite because of time neat, cause atmosphere to forecast difficulty, affect a flight possibly to attemper thereby, bring needless loss.
In addition, use did not do GPS Zhou Shu to retroflexion the receiver of processing comes the infrastructure field that time service also can run to a few automation produces an effect, the BITS system that for instance electric power, communication and financial field place use. If BITS system consulted only signal of GPS time service, the time that can create BITS system jumps change, the likelihood can cause a system to break down, influence masses is used. In financial domain, cause possibly still cannot finish close an account, bring pecuniary loss to the user.
How to eliminate hidden danger?
He Zhi force expresses, retroflexion to answer GPS Zhou Shu problem, on one hand, each industries should contact GPS receiver to supply ahead of schedule square, seek advice to whether because GPS Zhou Shu retroflexions,exist bring issue of time service mistake, if exist, should ask GPS receiver supplies square newer firmware. On the other hand, use GPS will have the user of time service, should have done beforehand case and emulation test, eliminate hidden danger.
How to check receiver to whether you can be retroflexioned by GPS Zhou Shu influence? To average user, the GPS receiver that can contact oneself is supplied square, whether is the inquiry put in this hidden trouble, when can appear, update firmware in time. To professional user, can use GPS signal simulator to install signal hair to broadcast hour, set the aleatoric hour after April 6, 2019, check GPS receiver to whether can be retroflexioned by Zhou Shu repeatedly influence.
Does north fight a system to also have Bug?
Regard as eponymous as American GPS whole world as one of navigation system of 4 big satellites, the north of our country own research and development fights navigation system to already became a piece of credit of contemporary China of the eye " national calling card " . So does north fight navigation system to have similar Bug?
Xu Ying says, the north of our country fights navigation system to also be put in BD Zhou Shu to retroflexion problem, but the north of our country fights a system to design personnel to combine GPS Zhou Shu to retroflexion cycle weak point and circumstance of service life of general GNSS receiver, when the design, its week count expresses with 13bit, retroflexion cycle is 8192 weeks, it is 160 years probably, thereby effective avoid this problem. Actually, number of week of corresponding satellite navigation system retroflexions problem, inevitable conference appears, just retroflexion periodic accident problem, but reasonable algorithm can be designed in user receiver and avoid this problem, become the perpetual calendar that does not have Bug.
