Carrier-Phase Multipath Mitigation Based on Adaptive Wavelet Packet Transform and TB Strategy

2020 ◽  
Vol E103.B (5) ◽  
pp. 591-599
Author(s):  
Yanxi YANG ◽  
Jinguang JIANG ◽  
Meilin HE
Keyword(s):  
Carrier Phase ◽  
Wavelet Packet ◽  
Wavelet Packet Transform ◽  
Multipath Mitigation ◽  
Adaptive Wavelet

Assessment of wavelets analysis for carrier-phase multipath mitigationThis article is one of a series of papers published in this Special Issue on the theme GEODESY.

2009 ◽  
Vol 46 (8) ◽  
pp. 627-636
Author(s):  
Ahmed A. El-Ghazouly ◽  
Mohamed Elhabiby ◽  
Naser El-Sheimy
Keyword(s):  
Carrier Phase ◽  
Deformation Monitoring ◽  
Double Difference ◽  
Multipath Mitigation ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Adaptive Wavelet ◽  
Multipath Error ◽  
Phase Measurements ◽  
Search Volume

In carrier-phase measurements, which are the most precise observations for Global Positioning System (GPS) relative positioning, multipath error is still a factor that interferes with achieving the desired accuracy. Various improvements in receiver and antenna technologies, as well as modeling strategies, have resulted in better ways of coping with this error source. However, errors caused by multipath can be as large as 5 cm, which is not an acceptable accuracy, especially in precise surveying applications like deformation monitoring. In this paper, a full assessment of different wavelets techniques that can be used in multipath mitigation is made to evaluate the optimum way of using wavelets to reduce or remove this type of error. Also, a new approach based on the wavelet detrending technique is introduced to remove carrier-phase multipath error in the measurement domain. To mitigate multipath, GPS double-difference observables are fed to an adaptive wavelet analysis procedure based on high- and low-pass filter decomposition with different levels of resolution. Consequently, the observable sequences are corrected; these corrected observables can then be used to reduce the ambiguity search volume during the initial float solution stage. Meanwhile, double-difference observations with multipath mitigation offer an efficient method for obtaining a better baseline solution.

scholarly journals Fast Texture Synthesis in Adaptive Wavelet Packet Trees

2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
Ying-Shen Juang ◽  
Hsi-Chin Hsin ◽  
Tze-Yun Sung ◽  
Carlo Cattani
Keyword(s):  
High Frequency ◽  
Texture Synthesis ◽  
Wavelet Packet ◽  
Low Frequency ◽  
Computation Time ◽  
Wavelet Packet Transform ◽  
Synthesis Process ◽  
Adaptive Wavelet ◽  
Hierarchical Trees ◽  
Speed Up

Wavelet packet transform known as a substantial extension of wavelet transform has drawn a lot of attention to visual applications. In this paper, we advocate using adaptive wavelet packet transform for texture synthesis. The adaptive wavelet packet coefficients of an image are organized into hierarchical trees called adaptive wavelet packet trees, based on which an efficient algorithm has been proposed to speed up the synthesis process, from the low-frequency tree nodes representing the global characteristics of textures to the high-frequency tree nodes representing the local details. Experimental results show that the texture synthesis in the adaptive wavelet packet trees (TSIAWPT) algorithm is suitable for a variety of textures and is preferable in terms of computation time.

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