The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Inter-satellite link technology is one of hot issues in current satellite navigation field and construction of inter-satellite link system cannot be completed without the cooperation and supports of ground anchor stations. In this paper, with respect to time synchronization issue which is of great importance in the construction of anchor stations for inter-satellite link, key technological issues...
With the development of GNSS, the design and optimum selection of the ranging code is of significant importance for navigation system design. This paper describes the generation of the Weil code based on the design of ranging code. And then in order to select ranging codes of better performance, the paper describes a new optimum selection method in detail. This method is a combination of code selection...
Nowadays, multipath remains as an unsolved key problem for high precision applications, such as satellite navigation and position. Because GNSS broadcasted signals are subject to reflection and diffraction, just like any other type of electromagnetic waves, multipath is caused by the reception of direct signal together with the reflected or/and diffracted signals at the same time. Multipath will result...
With the development of science and technology, time and frequency is playing an important role in many fields. Common-view method is one of the main methods for remote precise time and frequency transfer. The method of common-view is characterized by higher precision, good convenience in use, and cheap instrument, so the study on the application of common-view is of great value. A new method to design...
A variety aerospace applications require high-precision time frequency reference and the corresponding time synchronization method. This paper studies the movement characteristics of the satellite in the constellation, and proposes an autonomous dynamic two-way high-precision time synchronization algorithm with adaptation to between the moving satellites. According to the given three-tier constellation...
In this paper, Ultra wideband technology and the main features of indoor positioning technology is introduced, focusing on the design and establishment of a UWB-based indoor positioning system model, the transceiver structure of the system is determined, and then location algorithm, the receiver synchronization and channel estimation and other key technologies conducted in-depth study. On this basis,...
A new evaluating software is developed for analyzing the communication performance of GNSS (Global Navigation Satellite System) baseband signals. And four domains of time, frequency, modulation and correlation are evaluated using this new developed software for collected GNSS space transmission signal. Some parameters which are the yardsticks of good performance are calculated using this novel evaluating...
Intersatellite clock offset measurement is one of the key techniques to implement intersatellite time synchronization. Two-way time transfer is one of the methods with the high-accuracy applied to clock offset measurement. Since satellite moves at high speeds, the propagation delay of two-way time transfer signals between moving satellites is not equal. Therefore, the clock offset obtained with this...
Precise indoor positioning is becoming increasingly important in commercial, military and public service applications for tracking people and asset. Ultra Wide Band (UWB) can provide high accuracy position with strong anti-jamming and low power consumption. It is very suitable for indoor positioning application. This paper will put emphasis on indoor positioning system based on UWB.Analysis and implementation...
Precise indoor positioning is becoming increasingly important in commercial, military and public service applications for tracking people and asset. Ultra Wide Band (UWB) can provide high accuracy position with strong anti-jamming and low power consumption. By combining orthogonal frequency-division multiplexing (OFDM) with multi-band, MB-OFDM systems can capture multi-path energy more efficiently...
Ultra wideband (UWB) wireless communication technology has been regarded as a very important way of indoor short distance, high speed transition at present. In this paper the system structures and working principles of indoor positioning using UWB are introduced. The basic location principles and realization ways based on TDOA (time-difference-of arrival) are discussed and a new method to estimate...
In this paper, based on Anylogic6.0 simulation software, some simulation models of queuing systems with different queuing disciplines are established, including first come first service, last come first service and random service. Compared with the theoretical values, the accuracy of the experiment data is verified. Finally, with comparative analysis of experiment data, we show that under a special...
The Intra-Orbit-Links(IOL), which play the key role during the satellite communication, is introduced. The geometrical model of IOL in the Treble-Layer Satellite Network(TLSN) is constructed. The IOL inside different kinds of TLSN is simulated, that not only the advice of research on More-Layer Satellite Network is given, but the conclusion that a MEO-GEO-IGSO TLSN is batter than kinds of constellation...
Multi-band orthogonal frequency division multiplexing (MB-OFDM) is a suitable solution to implementation of high speed data transmission in ultra wideband (UWB) spectrum by dividing the spectrum available into multiple bands. MB-OFDM system structure and transmitted signal is introduced in this paper. Channel models are fundamental to the study and design of communication systems. A survey on indoor...
The key technology in multi-band orthogonal frequency division multiplexing ultra wide band (MB-OFDM-UWB) system is inverse fast Fourier transforms (IFFT) which is used to implement OFDM modulation. However, the realization of multiplier with field programmable gate array (FPGA) in IFFT needs a large number of resources. This paper describes the implementations of IFFT based on coordinate rotation...
The convolutional code cell is an essential part in a transmitter of multi-band orthogonal frequency division multiplexing ultra wide band (MB-OFDM-UWB) system introduced in this paper as a kind of useful channel coding to offer more protection against all kinds of channel noise under indoor channel environments. In this paper, some kinds of convolutional codes for MB-OFDM-UWB system are designed...
Integrated navigation system can help to solve the performance and application problems and limitations of the navigation equipment. Data fusion technology is one of the kernel parts in integrated navigation systems. In this paper, the current advances of this technology are introduced, with the architecture of a multi-sensor navigation system given and its principles and structure presented in detail...
Multi-Band Orthogonal Frequency Division Multiplexing (MB-OFDM) is a suitable solution to implementation of high speed data transmission in ultra wideband spectrum by dividing the spectrum available into multiple bands. The baseband of transmitter is one of the most important parts in MB-OFDM system. The structure of MB-OFDM system transmitter is introduced in this paper and the design of transmitter...
System integrated clock (SIC) plays an important role in implementing the high-accuracy constellation automatic time synchronization and information exchange. In the establishment of SIC, error and noise are unavoidably introduced. In the paper, various error sources in the process are analyzed at first, and then an error-reduction method under the model of two-way plus common view time comparison...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.