KEYWORDS: Filtering (signal processing), Data processing, Detection and tracking algorithms, Satellites, Data centers, Clocks, Receivers, Ranging, Troposphere, Data fusion
In the outdoor scene, most users’ localization requirements can be fulfilled through the Beidou system (BDS). However, when facing some challenging environments with serious shadowing and reflection, such as the positioning of seaport containers, the number of observations of the BDS will decrease and the confidence of the observed pseudorange will degrade. In this case, auxiliary data must be added in order to achieve high-precision positioning. Ultra-wide band (UWB) has strong penetrating power and nanosecond temporal resolution, meantime it has the characteristics of highprecision positioning, so this paper adopts the combined positioning method of BDS and UWB to locate targets in the challenging environment. In this paper, appropriate UWB layout location is selected according to the principle of minimum geometric dilution of precision (GDOP). For BDS/UWB co-location system, this paper proposes a new adaptive weighted method based on pseudorange residual detection for weighted least squares (WLS) localization algorithm. Based on the WLS localization algorithm, the Kalman filter (KF) is introduced to improve the WLS performance, so this paper adopts a WLS and KF positioning algorithm (WLS-KF) for BDS/UWB co-location system. The simulation results show that this positioning method can achieve the positioning accuracy below m-level, which can meet the demand of high precision positioning in the complex environment such as seaport containers.
The non-binary low density parity check coded continuous phase modulation (LDPC-CPM) system improves the reliability and effectiveness of the digital signal transmission by relying on the error-correcting performance of nonbinary LDPC code and the spectral efficiency of high-order CPM. However, due to the channel interference during transmission and the phase jitter of local oscillator at the receiving end, the introduced carrier phase offset will drastically deteriorate the system performance. In order to solve the above problem, combining the output characteristic of LDPC iterative decoding, this paper studies the code-aided carrier phase synchronization algorithm suitable for nonbinary LDPC-CPM system, the basic idea is to use the decoding soft information to aid the synchronization parameter estimation, and carrier phase correction of the system is accomplished by joint iteration of synchronizer, demodulator and decoder. Theoretical research and simulation results show that under low signal-to-noise ratio (SNR) conditions, the code-aided synchronization algorithm for non-binary LDPC-CPM system solves the problem that the traditional codeaided synchronization algorithm cannot be applied to M-ary CPM signal, so that it can achieve effective carrier phase synchronization in the large phase offset range and obtain approximate ideal system performance at the cost of low system complexity.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.