It is shown to be a relevant study involving terrestrial methods of measurement, such as: forward and backward intersections, geometric leveling, trigonometric leveling with short distance targeted and spatial positi...It is shown to be a relevant study involving terrestrial methods of measurement, such as: forward and backward intersections, geometric leveling, trigonometric leveling with short distance targeted and spatial positioning GNSS methods, for the definition of field reference points and field-object points located in rough terrain. The geodesic structures were implemented in the Historic Site of Olinda employing GNSS (global navigation satellite system) receivers, total stations and digital level. The historical site of Olinda was recorded by UNESCO as Historical and Cultural Heritage of Humanity. The study area is located in the center of the busiest site with a quite roughly relief. This area has been studied since 2007 involving Research of Scientific Initiation and Pos-Graduation Course. This paper aims to present the realized experiments for the implementation and definition of geodesic structures in environments with very rough relief, including large old houses and historic monuments.展开更多
Signal structure design is an important part of satellite navigation system research,which directly affects navigation performance.Signal performance parameters are analyzed and performances of BPSK modulated signals ...Signal structure design is an important part of satellite navigation system research,which directly affects navigation performance.Signal performance parameters are analyzed and performances of BPSK modulated signals and BOC modulated signals are compared.Aiming at requirements of high navigation precision and high anti-jamming ability,a new navigation signal structure based on complex carrier modulation is proposed and performances of the signal are researched with different parameters.A synchronization algorithm is put forward according to the signal characteristics,and the synchronization performance is qualitatively analyzed.Next,the applications of the complex carrier modulated signal are discussed,which include anti-jamming,navigation enhancement,power combing and so on.Simulations and analysis show that the proposed navigation signal structure based on complex carrier modulation has good navigation capabilities and anti-jamming abilities,which deserves further study.展开更多
Satellite navigation is playing an important role in social life.The performances of the services a navigation system provides are the concern of the builders and users.The signal structure determines the inherent abi...Satellite navigation is playing an important role in social life.The performances of the services a navigation system provides are the concern of the builders and users.The signal structure determines the inherent ability of a satellite navigation system to provide these services.Therefore,it is necessary and reasonable to optimize the signal in the initial design.The waveforms of signals in satellite navigation chips are an important aspect of the signal's structure,which impact the characteristics of the autocorrelation function and power spectrum in the time domain and frequency domain.The range accuracy of a navigation system is usually described by its Gabor Bandwidth.The Gabor Bandwidth of the Binary Offset Carrier (BOC) modulation in next-generation GNSS signal systems is not optimal.This paper presents a signal expression based on Multilevel Coded Symbol (MCS) signals,which can describe the fine structure of navigation signals.With this expression,we can optimize the Gabor Bandwidth of the signal,and find out the corresponding MCS vector and chip waveform,so as to get higher range accuracy.The method in this paper,in theory,is of great value in the design of next-generation navigation signals.展开更多
文摘It is shown to be a relevant study involving terrestrial methods of measurement, such as: forward and backward intersections, geometric leveling, trigonometric leveling with short distance targeted and spatial positioning GNSS methods, for the definition of field reference points and field-object points located in rough terrain. The geodesic structures were implemented in the Historic Site of Olinda employing GNSS (global navigation satellite system) receivers, total stations and digital level. The historical site of Olinda was recorded by UNESCO as Historical and Cultural Heritage of Humanity. The study area is located in the center of the busiest site with a quite roughly relief. This area has been studied since 2007 involving Research of Scientific Initiation and Pos-Graduation Course. This paper aims to present the realized experiments for the implementation and definition of geodesic structures in environments with very rough relief, including large old houses and historic monuments.
文摘Signal structure design is an important part of satellite navigation system research,which directly affects navigation performance.Signal performance parameters are analyzed and performances of BPSK modulated signals and BOC modulated signals are compared.Aiming at requirements of high navigation precision and high anti-jamming ability,a new navigation signal structure based on complex carrier modulation is proposed and performances of the signal are researched with different parameters.A synchronization algorithm is put forward according to the signal characteristics,and the synchronization performance is qualitatively analyzed.Next,the applications of the complex carrier modulated signal are discussed,which include anti-jamming,navigation enhancement,power combing and so on.Simulations and analysis show that the proposed navigation signal structure based on complex carrier modulation has good navigation capabilities and anti-jamming abilities,which deserves further study.
基金supported by the Best Paper Award of China Satellite Navigation Conference (Grant No.CSNC2010-QY-003)the CAST Innovation Foundation (Grant CAST20100405)
文摘Satellite navigation is playing an important role in social life.The performances of the services a navigation system provides are the concern of the builders and users.The signal structure determines the inherent ability of a satellite navigation system to provide these services.Therefore,it is necessary and reasonable to optimize the signal in the initial design.The waveforms of signals in satellite navigation chips are an important aspect of the signal's structure,which impact the characteristics of the autocorrelation function and power spectrum in the time domain and frequency domain.The range accuracy of a navigation system is usually described by its Gabor Bandwidth.The Gabor Bandwidth of the Binary Offset Carrier (BOC) modulation in next-generation GNSS signal systems is not optimal.This paper presents a signal expression based on Multilevel Coded Symbol (MCS) signals,which can describe the fine structure of navigation signals.With this expression,we can optimize the Gabor Bandwidth of the signal,and find out the corresponding MCS vector and chip waveform,so as to get higher range accuracy.The method in this paper,in theory,is of great value in the design of next-generation navigation signals.