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Accutenna™

Tallysman的Accutenna™技术已证明其能够提供卓越的多路径信号抑制,能提供超越其尺寸和价格的精度。 Accutenna™技术:
•采用Tallysman独特的双馈电平板天线技术

•在整个天线带宽上提供真正的圆形响应

•提供卓越的多路径和交叉极化信号抑制

•预滤波可选,对近带信号额外保护

•适用于仅GPS L1或多星系(GPS,GLONASS,BeiDou和Galileo)
GNSS正在改变。越来越多的接收机能够访问多星系(GPS / GLONASS / BeiDou / Galileo)。从前单馈天线对于单星座/单频率接入完全没有问题,但在今日世界,Tallysman的Accutenna™技术是必要的,以提供您所需的精度。
 
什么是双馈天线?
双馈陶瓷贴片架构  
双馈天线是两个正交取向的偶极。当每个偶极子接收到的信号相加时,两个信号是90度相移时,能完美地在天线的全带宽上复制圆极化响应。这极大地改善了对交叉极化(多路径)信号的抑制,并因此提供比单馈电天线高得多的精度。

单馈电贴片天线仅在其单谐振频率是圆形的。当载波离开单个谐振频率时,它们越来越呈现椭圆形。因此,当使用单个馈电天线接入两个星座,例如GPS(1575.42MHz)和GLONASS(1602MHz)时,它被调谐到两个频率的中点;通常为1590MHz。结果是GPS和GLONASS信号对于这个天线看起来是椭圆的。因此,当单馈电天线接收GPS和GLONASS信号时,其还接收也是椭圆的交叉极化(多路径)信号。最终结果是统计学上非常差的精度。

图2(左边)说明了这一点。在1590MHz的调谐频率下,单馈电天线具有约25dB的交叉极化信号抑制,但在中心频率1575.42MHz和1602MHz处仅有约5dB的抑制。

GNSS接收机有赖天线呈现的信号质量。没有接收机可以完全减轻弱天线的影响。

图2(右边)很好地使用说明了Accutenna™技术的效果,在整个带宽上提供了圆形响应。在两个中心频率处的交叉极化抑制明显更好:在1575.42MHz大约25dB,在1602MHz大约20dB。
Tallysman的Accutenna™技术被应用于许多天线。该技术证明了其对于多径抑制的优越性,其为接收机提供了最佳机会,可靠精确地报告位置坐标,如在Accutenna ™技术的独立并行测试中贴片天线同时访问GPS L1和GLONASS G1,而不是单个反馈。

 

Accutenna Technology™

Tallysman’s Accutenna™ technology has proven its ability to provide superior multi-path signal rejection thereby providing un-matched precision for its size and price.  Accutenna™ technology:

  • Employs Tallysman’s unique dual feed patch technology
  • Provides truly circular response over the entire antenna bandwidth
  • Provides superior rejection of multi-path and cross polarized signals
  • Offers pre-filtering option to provide additional protection from near band signals
  • Is available for only GPS L1 coverage or multi-constellational coverage (GPS, GLONASS, BeiDou, and Galileo)

GNSS is changing.  An increasing number of receivers are capable of accessing multiple constellations (GPS / GLONASS / BeiDou /Galileo).  Yesterday’s single feed antennas were perfectly fine for single constellation / single frequency access, but in today’s world, Tallysman’s Accutenna™technology is necessary to provide the precision you demand.

What is a Dual-feed Antenna? 双馈天线

Dual Feed Patch Architecture

Dual Feed Patch Architecture 双馈平板架构

Dual feed antennas are two orthogonally oriented dipoles.  When the received signals of each dipole are summed, after a 90 degree phase shift of one of the signals, it perfectly replicates the circular response over the full bandwidth of the antenna.  This greatly improves rejection of cross polarized (multi-path) signals and thus provides much higher precision than single feed antennas.

A single feed patch antenna is circular only at its single frequency of resonance.  As carriers depart from this single frequency of resonance, they will appear increasingly more elliptical to this antenna.  So when a single feed antenna is used to access two constellations, such as GPS (at 1575.42 MHz) and GLONASS (at 1602 MHz), it is tuned to the mid-point of the two frequencies; typically 1590 MHz.  The result is the GPS and the GLONASS signals appear elliptical to this antenna.  So when the single feed antenna receives the GPS and the GLONASS signals, it also receives cross-polarized (multi-path) signals which are also elliptical.  The end result is statistically very poor precision.

Figure 2 illustrates this point well.  At the tuned frequency of 1590 MHz, the single feed antenna has a cross polarized signal rejection of about 25 dB but only about 5 dB of rejection at the frequencies of interest;  1575.42 MHz and 1602 MHz.

GNSS receivers are at the mercy of the quality of the signal presented by the antenna.  No receiver can fully mitigate the effects of a poor antenna.

Figure 2 - Response of a Single Feed Antenna versus Response of an Accutenna antenna

Figure 2 – Response of a Single Feed Antenna versus Response of anAccutenna antenna

Figure 2 provides an excellent illustration of the effects of using Accutenna™technology which provides a circular response over the entire bandwidth.  The cross polarization rejection at the two frequencies of interest is significantly better:  approximately 25 dB at 1575.42 MHz and 20 dB at 1602 MHz.

Videos

Youtube: https://youtu.be/eCrzwcCLfnQ

Youku:  http://v.youku.com/v_show/id_XMTI5NjM0NTUwMA==.html?from=y1.7-1.2