Indoor and outdoor positioning system for Beidou fusion 5G

Recently, my country’s Beidou-3 satellite system has successfully networked, and the application of the Beidou-3 satellite system will become the trend of social development in the future. In the complex environment of multi-path interference in the indoor diplomatic area, the Beidou system will often be interfered by various errors in the calculation, which leads to the limitation of the positioning accuracy of the Beidou system. This paper proposes that 5G fusion Beidou for indoor and outdoor positioning can effectively solve the problems of interference affecting accuracy in the indoor and foreign circles, and make the positioning accuracy reach the sub-meter level.

OSA Patient Monitoring Based on the Beidou System

This paper presents an OSA patient interactive monitoring system based on the Beidou system. This system allows OSA patients to get timely rescue when they become sleepy outside. Because the Beidou position marker has an interactive function, it can reduce the anxiety of the patient while waiting for the rescue. At the same time, if a friend helps the OSA patients to call the doctor, the friend can also report the patient's condition in time. This system uses the popular IoT framework. At the bottom is the data acquisition layer, which uses wearable sensors to collect vital signs from patients, with a focus on ECG and SpO2 signals. The middle layer is the network layer that transmits the collected physiological signals to the Beidou indicator using the Bluetooth Low Energy (BLE) protocol. The top layer is the application layer, and the application layer uses the mature rescue interactive platform of Beidou. The Beidou system was developed by China itself, the main coverage of the satellite is in Asia, and is equipped with a high-density ground-based augmentation system. Therefore, the Beidou model improves the positioning accuracy and is equipped with a special communication satellite, which increases the short message interaction function. Therefore, patients can report disease progression in time while waiting for a rescue. After our simulation test, the effectiveness of the OSA patient rescue monitoring system based on the Beidou system and the positioning accuracy of OSA patients have been greatly improved. Especially when OSA patients work outdoors, the cell phone base station signal coverage is relatively weak. The satellite signal is well-covered, plus the SMS function of the Beidou indicator. Therefore, the system can be used to provide timely patient progress and provide data support for the medical rescue team to provide a more accurate rescue plan. After a comparative trial, the rescue rate of OSA patients using the detection device of this system was increased by 15 percentage points compared with the rescue rate using only GPS satellite phones.

A Novel Big Data Collection System for Ship Energy Efficiency Monitoring and Analysis Based on BeiDou System

The call for green shipping is increasing, and the reduction of greenhouse gas emissions from ships becomes more and more important. Traditional ship energy efficiency monitoring is based on the noon reports, which are susceptible to human error and have a time delay. Many ship energy efficiency monitoring systems have been designed and developed, but they usually cannot send data to the shore in time. In order to identify abnormal fuel consumption in time, this paper realizes a big data collection system for ship energy efficiency monitoring based on the BeiDou System. The system installed on two sister container ships has already collected a lot of data. Big data analysis methods, such as principal component analysis (PCA) and correlation analysis, are applied in the system to realize data visualization and analysis. Using PCA, it turns out that the shaft power of the main engine is related to a certain ship speed, which is also affected by load and weather conditions, and is the biggest factor in determining fuel consumption. To realize the assessment of hull fouling and the optimization of ship trim, a useful physics-based analysis is proposed. The analysis shows that the fouling of ship body greatly increases its resistance. Our analysis method can also find the best trim under specific loading condition. All these points are important for reducing fuel consumption and improving ship efficiency.

A Multipath Processing Technology Based on Multiparameter-Combined Observation in GNSS

In the Global Navigation Satellite System (GNSS), the multipath error affected by many aspects is the main error source that affects satellite navigation, and it is difficult to establish a much more accurate model to analyze it. Based on the ground multipath reflection model, it firstly deeply studies the influence of GNSS satellite orbit parameters on multipath fading frequency and establishes a multipath signal model related to satellite orbit parameters. Secondly, the influence of carrier phase cycle slip, receiver clock adjustment, and GNSS satellite orbit on multiparameter- (MP-) combined observations is analyzed in detail based on the measured data. Finally, aiming at the common phenomenon of code-carrier divergence in the Beidou system, the elevation-based pseudorange correction model and a sidereal filtering are built to correct the MP errors; experiments with measured data show that there is a fluctuation range reduction of 35.7% after sidereal filtering when the receiver reaches a steady state.

Centimeter-Level Precise Orbit Determination for the Luojia-1A Satellite Using BeiDou Observations

Luojia-1A is a scientific experimental satellite operated by Wuhan University, which is the first low earth orbiter (LEO) navigation signal augmentation experimental satellite. The precise orbit is the prerequisite of augmenting existing Global Navigation Satellite System (GNSS) performance and improves users’ positioning accuracy. Meanwhile, LEO precise orbit determination (POD) with BeiDou-2 observations is particularly challenging since it only provides regional service. In this study, we investigated the method of precise orbit determination (POD) for Luojia-1A satellite with the onboard BeiDou observation to establish the high-precision spatial datum for the LEO navigation augmentation (LEO-NA) system. The multipath characteristic of the BeiDou System (BDS) observations from Luojia-1A satellite is analyzed, and the elevation-dependent BeiDou code bias is estimated with the LEO onboard observations. A weight reduction strategy is adopted to mitigate the negative effect of poor BeiDou-2 geostationary earth orbit (GEO) satellites orbit quality, and the Luojia-1A orbit precision can be improved from 6.3 cm to 2.3 cm with the GEO weighting strategy. The precision improvement of the radial direction, along-track, and out-of-plane directions are 53.47%, 47.29%, and 76.2%, respectively. Besides, tuning the pseudo-stochastic parameters is also beneficial for improving orbit precision. The experiment results indicate that about 2 cm overlapping orbit accuracy are achievable with BeiDou observations from Luojia-1A satellite if proper data processing strategies are applied.

Precise Positioning with the Modified Ambiguity Function Approach using BDS and GPS observations

<p>For many years GPS and GLONNAS were leading navigation systems. However, recent years two new navigational systems have appeared. These systems are the European Galileo System and the Chinese BeiDou System (BDS). The full operability of both systems is foreseen for 2020. The BDS is quickly developing in last years and still increasing number of satellites allows to use this system for positioning. GPS and BDS systems share some of their signals frequencies. These shared signals frequencies allows to combine observation of both systems. The goal of this study is use the BDS along with GPS for positioning purpose.</p><p>For test purpose a self-made software was created in MatLab. It consists of three modules.  First is responsible for reading RINEX files, second for the DGPS or the DGNSS in case of combined GPS and BDS observations and the third one uses The Modified Ambiguity Function Approach (MAFA) method for precise positioning purposes. MAFA is a method of processing GNSS carrier phase observations. In this method the integer nature of  ambiguities is taken into account using appropriate form of mathematical model. The theoretical Foundations of Precise Positioning Using MAFA will be presented. For test purpose data from three different days for the same baseline was used. Test was divided on two parts. In the first part short static sessions were performed for GPS only BDS only and for GPS and BDS combination. In the second part data was tested in RTK mode for GPS only, BDS only and for GPS and BeiDou System combination.</p><p>BDS allows to obtain an accuracy on the same level as GPS. The usage of GPS and BDS combinations allows to increase the precision of the obtained result comparing to GPS only solution. Very important thing is to remember about inter system bias (ISB) - the difference between the receiver hardware delays affecting the signals from different systems, that can affect for the results.</p>

STUDY ON THE PERFORMANCE OF BEIDOU HIGH-PRECISION REFERENCE STATION NETWORK IN BEIBU GULF OF GUANGXI

Beidou high-precision reference station network in Beibu Gulf of Guangxi consists of five parts, namely Beidou reference stations, the data processing system, the operation and service platform, the data broadcast system and user terminals. It is an important infrastructure for the construction of the China-ASEAN Information Harbor. Since its operation, the system has contributed significantly to the industrial development in Guangxi and the mass application of Beidou. This paper focuses on the operation of Beidou high-precision reference station network in Beibu Gulf of Guangxi from the perspectives of performance, navigation and positioning accuracy, application experience, etc. Experimental results demonstrated that: in the area of Beibu Gulf of Guangxi, the application of Beidou Navigation Satellite System (BDS) has significantly increased the number of satellites observed and enhanced the spatial accessibility of the system. The percentage of fixed solutions in the spatial accessibility test of the system was about 87.3%; the network-wide time availability within the effective coverage of the system was 92.7%; the internal accordant accuracy of points in Beibu Gulf BDS was 37.7% and 33.3% higher than the dual constellation system (GPS+GLONASS) in the horizontal and the vertical directions respectively, and the average external accordant accuracy was 20.60% higher than the dual constellation system in the horizontal direction (equivalent in the vertical direction). This paper objective reflected the present construction and utilization situation of Beidou high-precision reference station network in Beibu Gulf of Guangxi, which would be of great significance to the construction and development of the Beidou system.