原创 Rakon for Aerospace <一>

2010-11-13 07:50 1312 7 8 分类: 消费电子


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New  ‘State-of-the-Art’ Thermal

Sensitivity Achieved in Rakons Ultra Stable Quartz Crystal Oscillator for Space Applications.*

 

In 2009 further research went into  improving the  thermal sensitivity of RAKONs space quartz crystal Ultra  Stable Oscillator (USO). RAKON France (CEPE until  1998,  C-MAC from 1998 to 2007,  and RAKON since early 2007) has been

working with  CNES (the  French Space Agency) to continuously improve performances of the  Ultra-Stable OCXO (USO): OUS- NG[1-2]. Its frequency sensitivity has a strong influence on final performance of the  DORIS system (Doppler Orbitography

and Radio-positioning Integrated by Satellite, CNES system) which uses RAKONs OCXO. The DORIS system is used in satellites such as Jason, Spot5, Cryosat, Pleiades Topex- Poseidon and Altika. Significant effort has been put  into additional improvements, mostly with  regards to the  thermal performances and preparation of the  new generation of a miniature USO. The quartz crystal oscillator has to be studied by taking a multi-physics approach. A part of this work  has

been conducted in a PhD thesis with  the  Femto-ST Institute and with  support from CNES [3-4].


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OUS-NG  Thermal  per formances

To increase the  resolution under the  centimeter in the  DORIS system, the  main improvement required is to reduce the frequency thermal sensitivity of the  USO. On figure 2, we present the  statistical distribution of the  relative frequency thermal sensitivity for OUSNG USO production. We can  see a repartition with  mean value at 7.10-13C  and standard deviation of 5.10-13/°C.  But for the  new DORIS requirement, the  frequency thermal sensitivity mean value must be reduced to 2.10-13C

and with  a standard deviation of 3.10-14/°C,  which is state- of-the-art and leading in terms of space USO performance. At the beginning of the  study, the  usual tools used for the  simulation (mechanical simulation and thermal simulation) seemed to not be sufficient in estimating and explaining the  total frequency drift in temperature. So a full 3D thermo-mechanical simulation of the USO was  conducted, with introduction of the piezo-electric phenomena of the resonator [3-8].


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A Multi-physics Approach

The USO is a complex assembly of mechanical and electronic parts. Rakons USO is a Double Oven Controlled Crystal Oscillator (D-OCXO) and the  quartz crystal is very  sensitive

to temperature. So an important part of the  USO is dedicated to building very  stable thermal operating conditions for the quartz crystal. Figure 3 shows a possible approach to studying the  USO. Each  part has to be studied as an independent item at the  first step; then they have to be optimized with  mutual

interactions between 2 items at the  second step, then the  three

items studied together to reach the  ultimate performance.


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Jesse Wu(Jesse-wu@hotmail.com  MT:1303280675  QQ:81643653

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文章评论1条评论)

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用户1434349 2013-4-2 13:37

学习了,深有感触!

用户1612004 2012-3-12 00:18

感触很深,大部分人都停留在想象工作和计划工作阶段,把计划做的很完美,然而每次一丁点的小事都把整个计划打得稀巴烂,然后不停的重复着执行大同小异的计划,没有一点提升的空间,就这样怎么都感觉时间不够用,效率低下,日子看似过得很充实,其实心里很疲惫。前期的思考和快速的执行一定要深入脑子里,任何时候反应要快!非常赞同博主的几个观点,能够做到这几点你就是行业里的成功人士了。

用户1377758 2011-6-11 19:35

有道理!

jesse-wu_880567621 2011-5-20 02:33

怎么会变成这样了啊

用户1587310 2010-12-22 13:19

tongyi

用户1568173 2010-12-20 22:58

基本上同意!

用户1338771 2010-12-20 13:48

mark 一下

用户1585908 2010-12-16 12:30

有道理!

用户1277994 2010-12-15 14:30

找一份有趣的工作真的很难。但找到了觉得有趣就真能做下去吗?
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