Global Navigation Satellite Systems Report of a Joint Workshop of the National Academy of Engineering and the Chinese Academy of Engineering (2012) / Chapter Skim
Currently Skimming:
GNSS Open Signals Interference Issues and Countermeasures--Du Xiaodong, Wang Feixue, and Nie Junwei
GNSS Open Signals Interference Issues and Countermeasures--Du Xiaodong, Wang Feixue, and Nie Junwei
Pages 153-166
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 153... ...
Figure 1 shows the BD-2 system space components. CIVIL SIGNALS INTERFERENCE TYPES AND SOURCES Interference Types Civil signals will face two kinds of interference -- intentional interference and unintentional interference.
|
From page 154... ...
154 GLOBAL NAVIGATION SATELLITE SYSTEMS FIGURE 1 BD-2 system space components. Du-Wang_Fig1.eps bitmap FIGURE 2 Interference types.
|
From page 155... ...
Harmonics may interfere with a variety of civilian GPS band signals as shown in Table 1. Intentional Interference Sources The intentional interference usually comes from man-made jammers.
|
From page 156... ...
It took two months for investigators from the Federal Aviation Administration to track down the problem: a driver who passed by on the nearby New Jersey Turnpike each day had a cheap GPS jammer in his truck. In late 2009, researchers found that the B2 band of BD system Monitor Station reference receivers had been interfered with and was unable to obtain complete dual-frequency observations.
|
From page 157... ...
FIGURE 3 Detailed scheme of a 0.5 W GPS L1 suppressing jammer from the Internet, at http://servv89pn0aj.sn.sourcedns.com/~gbpprorg/mil/ gps/gps_jammer.png. Du-Wang_Fig3.eps bitmap, landscape 157
|
From page 158... ...
bitmap FIGURE 6 Low-power GPS mobile FIGURE 7 High-power GPS mobile Du-Wang_Fig7.eps Du-Wang_Fig6.eps integrated jammer. integrated jammer.
|
From page 159... ...
CIVIL SIGNAL INTERFERENCE COUNTERMEASURES Strengthen Navigation Frequency Spectrum Monitoring Within the Framework of Law In China, the usage and protection of radio spectrum resources and the investigation, production, distribution, and importation of the radio equipment have clear legal provisions. Relevant laws and regulations are: Real Right Law of the People's Republic of China, Criminal Law of the People's Republic of China, Radio Regulations of the People's Republic of China, and Radio Station License Regulations.
|
From page 160... ...
Its responsibilities are frequency spectrum monitoring, interference detection and investigation, matters of electromagnetic interference coordination, and transmission of radio waves in the air maintenance. Figures 10 and 11 show some radio monitoring equipment.
|
From page 161... ...
bitmap FIGURE 11 Radio monitoring vehicles. Source: Beijing Radio Administration Bureau, at Du-Wang_Fig12.eps http://www.bjrab.gov.cn/jcjc/jcs/twzs/20101221/364.shtml.
|
From page 162... ...
Modernized GNSS signals adopt new-style forward error correction coding schemes. High gain, soft-decision decoding can correct the navigation message error and improve the continuity of navigation in various kinds of interfer ence.
|
From page 163... ...
Spatial processing is mainly using the antenna array disposal techniques from the direction of signal to dis tinguish the interference. Adaptive space-frequency and space-time fil tering technology can effectively suppress various types of interference.
|
From page 164... ...
For the individual user equipment, because of its constraints on size and power, we propose to use time-domain to suppress narrowband interference. For the critical civilian infra structure equipment, we can appropriately increase the hardware scale and use the spatial-domain or polarization to enhance the anti-jamming capability and protect the safety of infrastructure.
|
From page 165... ...
1997. Analysis of Potential Interference Sources and Assessment of Present Solutions for GPS/GNSS Receivers[C]
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.