The Impact of Digital Navigation on Travel Behaviour

Digital navigation – the combined use of satellite positioning, digital mapping and route guidance – is in wide use for road travel yet its impact is little understood. Evidence is emerging of significant changes in use of the road network, including diversion of local trips to new major road capacity and increased use of minor roads, which have problematic implications for investment decisions and for the management of the network. However, the ability of digital navigation to predict estimated time of arrival under expected traffic conditions is a welcome means of mitigating journey time uncertainty, which is one of the undesirable consequences of road traffic congestion. There is very little available information about the impact of digital navigation on travel behaviour, a situation that needs to be remedied to enhance the efficiency of road network operation.Digital navigation – the combined use of satellite positioning, digital mapping and route guidance – is in wide use for road travel yet its impact is little understood. Evidence is emerging of significant changes in use of the road network, including diversion of local trips to new major road capacity and increased use of minor roads, which have problematic implications for investment decisions and for the management of the network. However, the ability of digital navigation to predict estimated time of arrival under expected traffic conditions is a welcome means of mitigating journey time uncertainty, which is one of the undesirable consequences of road traffic congestion. There is very little available information about the impact of digital navigation on travel behaviour, a situation that needs to be remedied to enhance the efficiency of road network operation.

Construction and Analysis of Intelligent Transportation Based on Computer Network Technology

With the continuous development of urbanization in China, urban traffic problems are gradually highlighted. In the future, intelligent transportation system will be the most important method to solve the demand of urban traffic. The realization of intelligent transportation system requires real-time perception and monitoring of road traffic conditions. Fortunately, with the continuous development of mobile communication, satellite positioning, Internet of Things, big data and other technologies, GNSS, RFID, microwave, geomagnetic, video and other acquisition methods have been widely used in information perception in the field of urban traffic. Based on the concept of intelligent transportation, this paper constructs an intelligent transportation system based on Internet network technology, which has a certain guiding significance for the construction of intelligent transportation under computer network technology.

Supporting Process of Independent Navigation Inside Buildings Based on Low-Energy Bluetooth Transmitters

Thanks to the use of satellite positioning systems (including GPS) the ability to determine a user's position in open spaces has become a necessary element of everyday life. Nowadays people cannot imagine moving in an "urban jungle” with paper maps without electronic support, but dozens of years ago those maps were more popular than satellite navigation. A similar revolution may also await navigations in closed spaces such as public or commercial buildings. Because as the urbanisation process, the surfaces of various buildings grow, which significantly impedes orientation in them, especially for the blind or visually impaired users. As satellite navigation systems are burdened with errors, which increase when trying to use them in confined spaces, it becomes necessary to use more accurate technology. As a step towards solving this problem, we propose a solution supporting the navigation of users, especially the visually impaired, inside buildings. Our approach is based on using low energy Bluetooth transmitters and a method of determining the user's position using the trilateration algorithm and the appropriate placement of transmitters in a space.

HYBRID MODELUNG FOR ELECTRODYNAMIC ANALYSIS OF LARGE-SIZED OBJECTS

Рассматриваются методы моделирования сложных электродинамических структур, которые состоят из антенны и объекта-носителя, размеры которого превышают 100 длин волн. При выполнении моделирования предлагается рассчитывать характеристики антенны с использованием метода конечного интегрирования, а при установке на платформу-носитель - с использованием метода геометрической дифракции и физической оптики. Развитие современных вычислительных сред позволилo реализовать систему гибридного моделирования, которая позволяет достичь высокой производительности, автоматизации и точности результатов полученного моделирования. При выполнении исследования изучалась ситуация с установкой антенны спутникового позиционирования на подводной лодке, причем размеры носителя антенны превышали 800 длин волн, что делало невозможным применение метода конечного интегрирования для решения задачи. Pассматривается три способа решения поставленной задачи: с использованием диаграммы направленности и ее ручным переносом на место планируемой установки антенны, однонаправленного метода гибридного моделирования с применением источника ближнего поля, гибридного моделирования с обратной связью между проектами. Получено, что наибольшую точность обеспечивает метод гибридного моделирования с обратной связью, однако его применение требует высокой скорости накопителя данных, а также занимает длительное время. Самым скоростным методом является метод гибридного моделирования с однонаправленной связью, так как обеспечиваются автоматизированный расчет и решение поставленной задачи The article discusses methods for modeling complex electrodynamic structures, which consist of an antenna and a carrier object whose dimensions exceed 100 wavelengths. When performing the simulation, we propose to calculate the characteristics of the antenna using the finite integration method and installed on the carrier platform using the method of geometric diffraction and physical optics. The development of modern computing environments has made it possible to implement a hybrid simulation system, which allows achieving high performance, automation, and accuracy of the results of the simulation. When performing the study, we studied the situation with the installation of a satellite positioning antenna on a submarine, and the dimensions of the antenna carrier exceeded 800 wavelengths, which made it impossible to use the finite integration method to solve the problem. The paper considers three ways to solve the problem posed: using the radiation pattern and its manual transfer to the site of the planned antenna installation, unidirectional hybrid modeling method using a near-field source, hybrid modeling with feedback between projects. We found that the highest accuracy is provided by the method of hybrid simulation with feedback, but its application requires a high speed of the data accumulator, and also takes a long time. The fastest method is the method of hybrid modeling with unidirectional communication, as it provides an automated calculation and solution of the problem

Research on BeiDou Satellite Positioning Algorithm Based on GPRS Technology

The BeiDou Satellite Navigation System of China can provide users with high precision, as well as all-weather and real-time positioning and navigation information. It can be widely used in many applications. However, new challenges appear with the expansion of the 5G communication system. To eradicate or weaken the influence of various errors in BeiDou positioning, a BeiDou satellite positioning algorithm based on GPRS technology is proposed. According to the principles of the BeiDou Satellite navigation system, the navigation and positioning data are obtained and useful information are extracted and sent to the communication network through the wireless module. The error is corrected by establishing a real-time kinematic (RTK) mathematical model, and the pseudorange is calculated by carrier phase to further eliminate the relativistic and multipath errors. Based on the results of error elimination, the BeiDou satellite positioning algorithm is improved and the positioning error is corrected. The experimental results show that the positioning accuracy and efficiency of the algorithm can meet the actual needs of real-time dynamic positioning systems.

An Adaptive Non-Uniform Vertical Stratification Method for Troposphere Water Vapor Tomography

Global Navigation Satellite System (GNSS) water vapor tomography provides a four-dimensional (4-D) distribution of water vapor in the atmosphere for weather monitoring. It has developed into a widely used technique in numerical weather prediction (NWP). Vertical stratification is essential in discretizing the tomographic region. Traditional discretization methods divide the tomographic area into regular voxels with an equal height interval, which ignores the dynamic exponential distribution of water vapor. In recent years, non-uniform stratification methods have been widely validated by tomographic experiments. However, such experiments have not proposed a specific calculation method for stratification thickness. Therefore, in this paper, we introduced an adaptive non-uniform stratification method that follows the exponential distribution of water vapor in the tomographic region and presented the process of iterative calculation to acquire the optimal stratification interval. The proposed approach was applied based on the exponential decreasing trend in water vapor with increasing altitude. Moreover, it could adaptively calculate the interval of stratification height according to water vapor content. The tomographic experiments were performed using Global Positioning System (GPS) data from 19 ground-based stations in the Hong Kong Satellite Positioning Reference Station Network (SatRef) from 1 to 31 August 2019. The results indicated that, compared to the traditional stratification method, the root mean square error derived from the proposed approach was reduced by 0.26 g/m3. Additionally, severe weather can negatively affect the accuracy of the tomographic results. The results also showed that the accuracy of the tomographic results was reduced with increasing altitude. Moreover, the performance of the tomographic water vapor fields below 3000 m was improved by the proposed approach.

MEC-Driven Fast Deformation Monitoring Based on GNSS Signal

In the deformation monitoring based on satellite positioning, the extraction of the effective deformation signal which needs plenty of computing resources is very important. Mobile-edge computing can provide low latency and near-edge computing agility for the deformation monitoring process. In this paper, we propose an edge computing network architecture to reduce the satellite observation time while maintaining a certain positioning accuracy. In such architecture, the state transition equation is established for monitoring, and the Kalman filter is used to reduce the error caused by the reduction of the observation time. At the same time, the method of determining the initial filter value and the filtering process are given. Through the actual monitoring of a certain section of railway track, the feasibility of the proposed method is proved.

Accuracy assessment of open - pit mine’s digital surface models generated using photos captured by Unmanned Aerial Vehicles in the post - processing kinematic mode

To evaluate the accuracy of the digital surface model (DSM) of an open-pit mine produced using photos captured by the unmanned aerial vehicle equipped with the post-processing dynamic satellite positioning technology (UAV/PPK), a DSM model of the Deo Nai open-pit coal mine was built in two cases: (1) only using images taken from UAV/PPK and (2) using images taken from UAV/PPK and ground control points (GCPs). These DSMs are evaluated in two ways: using checkpoints (CPs) and comparing the entire generated DSM with the DSM established by the electronic total station. The obtained results show that if using CPs, in case 1, the errors in horizontal and vertical dimension were 6.8 and 34.3 cm, respectively. When using two or more GCPs (case 2), the horizontal and vertical errors are at the centimetre-level (4.5 cm and 4.7 cm); if using the DSM comparison, the same accuracy as case 2 was also obtained.

Research on Acquisition and Tracking Algorithm of Global Satellite Positioning Receiver Based on UWB

In order to overcome the problems of the traditional algorithm, such as the time-consuming execution of acquisition instructions, low signal tracking accuracy, and low signal capture accuracy, a global satellite positioning receiver acquisition and tracking algorithm based on UWB technology is designed in this study. On the basis of expounding the pulse generation method and working principle in UWB technology, this paper analyzes in detail the characteristics of UWB technology, such as antimultipath, low power consumption, and strong penetration. Then, on the basis of window function filtering, in the process of three-dimensional search of global satellite positioning signal, firstly, the satellite signal entering the GPS software receiver is processed by RF front-end mixing and AD sampling, and then, the signal tracking and navigation message solving are completed according to the relationship between the influence factor and Doppler frequency offset. The experimental results show that the execution time of the acquisition instruction of the proposed algorithm varies between 1129 ms and 1617 ms; the signal tracking accuracy ranges between 0.931 and 0.951, and the signal capture accuracy ranges between 93.3% and 95.6%, which proves that the proposed algorithm has achieved the design expectation.