ImageVerifierCode 换一换
格式:PDF , 页数:5 ,大小:356.88KB ,
资源ID:793283      下载积分:10000 积分
快捷下载
登录下载
邮箱/手机:
温馨提示:
如需开发票,请勿充值!快捷下载时,用户名和密码都是您填写的邮箱或者手机号,方便查询和重复下载(系统自动生成)。
如填写123,账号就是123,密码也是123。
特别说明:
请自助下载,系统不会自动发送文件的哦; 如果您已付费,想二次下载,请登录后访问:我的下载记录
支付方式: 支付宝扫码支付 微信扫码支付   
注意:如需开发票,请勿充值!
验证码:   换一换

加入VIP,免费下载
 

温馨提示:由于个人手机设置不同,如果发现不能下载,请复制以下地址【http://www.mydoc123.com/d-793283.html】到电脑端继续下载(重复下载不扣费)。

已注册用户请登录:
账号:
密码:
验证码:   换一换
  忘记密码?
三方登录: 微信登录  

下载须知

1: 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。
2: 试题试卷类文档,如果标题没有明确说明有答案则都视为没有答案,请知晓。
3: 文件的所有权益归上传用户所有。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 本站仅提供交流平台,并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。

版权提示 | 免责声明

本文(ITU-R RS 1749-2006 Mitigation technique to facilitate the use of the 1 215-1 300 MHz band by the Earth exploration-satellite service (active) and the space research service (active.pdf)为本站会员(arrownail386)主动上传,麦多课文库仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对上载内容本身不做任何修改或编辑。 若此文所含内容侵犯了您的版权或隐私,请立即通知麦多课文库(发送邮件至master@mydoc123.com或直接QQ联系客服),我们立即给予删除!

ITU-R RS 1749-2006 Mitigation technique to facilitate the use of the 1 215-1 300 MHz band by the Earth exploration-satellite service (active) and the space research service (active.pdf

1、 Rec. ITU-R RS.1749 1 RECOMMENDATION ITU-R RS.1749 Mitigation technique to facilitate the use of the 1 215-1 300 MHz band by the Earth exploration-satellite service (active) and the space research service (active) (Question ITU-R 234/7) (2006) Scope This Recommendation describes the mitigation techn

2、ique of using filtering with Fourier transformation of the received signal. This technique applies to interference to synthetic aperture radars (SARs) in the 1 215-1 300 MHz band from other services with relatively small bandwidth. This Recommendation also provides typical parameters for spaceborne

3、active sensors to be used in the development of additional mitigation techniques. The ITU Radiocommunication Assembly, considering a) that the 1 215-1 300 MHz band is allocated on a primary basis to the Earth exploration-satellite service (active); b) that this band is used by spaceborne synthetic a

4、perture radars (SARs) which applications are to monitor, under all-weather and day and night conditions, deformation of the Earths surface in most land areas, natural disasters, the environment, forests, land use, and others; c) that the 1 215-1 300 MHz band is also allocated to the radiolocation se

5、rvice on a primary basis, and to the radionavigation service on a primary basis in a certain number of countries; d) that Recommendations ITU-R SA.516 and ITU-R SA.1282 show that the operation of SARs is possible without harmful interference in the same frequency band as systems operating in the rad

6、iolocation service, including wind profiler radars, with the possible exception of radio-location service systems using frequency-modulated pulsed radars; e) that performance and interference criteria of spaceborne active sensors are given in Recommendation ITU-R SA.1166; f) that air route surveilla

7、nce radars (ARSRs) with higher isotropically radiated powers than the main beam powers of wind profiler radars have been in operation in this band for many years and harmful interference to spaceborne active sensor operations is normally not observed, although degraded performance is sometimes obser

8、ved which may be attributed to ARSR transmissions, recommends 1 that a mitigation technique applicable to the spaceborne active sensors as shown in Annex 1 could be used to reduce interference from radiolocation and radionavigation radar systems operating in the 1 215-1 300 MHz band to these sensors

9、; 2 that typical parameters of spaceborne active sensors operating in the 1 215-1 300 MHz band given in Annex 2 should be used in the development of additional mitigation techniques. 2 Rec. ITU-R RS.1749 Annex 1 Mitigation technique for interference to spaceborne SARs 1 Introduction At some location

10、s on Earth, bright lines appear in the images of the L-band Synthetic Aperture Radar/Japanese Earth Resources Satellite-1 (L-SAR/JERS-1). These bright lines are due to harmful radio frequency interference (RFI) from terrestrial radars. It has been shown that it is possible to eliminate the interfere

11、nce that causes these bright lines by conducting frequency analysis of the input data. The use of this technique will make it possible to resolve the current problem of RFI to SARs operating in the 1 215-1 300 MHz band. 2 Method and results 2.1 Method The power level of the interfering signal is lar

12、ger than that of the desired signal of the SAR as the interfering signal is a direct emission from the transmitter of terrestrial radars. So, when a Fourier transformation on the received signal is performed, the interfering wave components appear as spikes on the frequency axis. Focusing on these c

13、haracteristics, as a pre-processing operation of range compression, we compare the power of each frequency “bin” with both the power spectra taken by Fourier transformation from the received signal and the original SAR signal (assuming that each components total power is equal to the desired compone

14、nt of the received signal) and 0 is adopted for the power of the specified frequency “bins” that have more power than expected (hereinafter referred to as “filtering”). Furthermore, considering that the interference components that are not correlated with the SAR signal are suppressed by about 30 dB

15、 through range compression, and to prevent original signal loss, a 3 dB or more difference is adopted as the criterion between the desired signal and the interference in this case. When processed using longer time units, there is a tendency for spiked frequencies to scatter widely among the frequenc

16、y spectrum and occasionally to result in the loss of the desired signal. For this reason, the received signal is divided into appropriate segments and then processed by methods such as Fourier transformation. (In this process, 1 024 azimuth lines are regarded as 1 segment.) 2.2 Interference suppress

17、ion process Specific procedures for the interference suppression process are as follows: Step 1 : Divide received signal, including interference, into small segments Signal of segment: Sr= received signal including interference, fr= SAR reference signal (power adjusted with Sr)Step 2 : Apply Fourier

18、 transformation to each segment Transformed spectrum: F(Sr), F(fr) Step 3 : Compare power in each frequency bin Compare |F(Sr)| to |F(fr)| Rec. ITU-R RS.1749 3 Step 4 : Identify frequency bins containing interference I = |F(Sr)| |F(fr)| 3 dB Step 5 : Generate filter Filter: A(): I 3 dB A() = 0, I 200 15/60

copyright@ 2008-2019 麦多课文库(www.mydoc123.com)网站版权所有
备案/许可证编号:苏ICP备17064731号-1