scholarly journals Ocean Real-Time Precise Point Positioning with the BeiDou Short-Message Service

2020 ◽  
Vol 12 (24) ◽  
pp. 4167
Author(s):  
Kaifei He ◽  
Duojie Weng ◽  
Shengyue Ji ◽  
Zhenjie Wang ◽  
Wu Chen ◽  
...  
Keyword(s):  
Real Time ◽  
Data Transmission ◽  
Short Message Service ◽  
Precise Point Positioning ◽  
Maximum Size ◽  
Global Navigation Satellite Systems ◽  
Short Message ◽  
Time Service ◽  
Message Service ◽  
Point Positioning

Real-time precise point positioning (RTPPP) is a popular positioning method that uses a real-time service (RTS) product to mitigate various Global Navigation Satellite Systems (GNSS) errors. However, communication links are not available in the ocean. The use of a communication satellite for data transmission is so expensive that normal users could not afford it. The BeiDou short-message service provides an efficient option for data transmission at sea, with an annual fee of approximately 160 USD. To perform RTPPP using BeiDou short messages, the following two challenges should be appropriately addressed: the maximum size of each BeiDou message is 78 bytes, and the communication frequency is limited to once a minute. We simplify the content of RTS data to minimize the required bandwidth. Moreover, the orbit and clock corrections are predicted based on minute-interval RTS orbital and clock corrections. An experiment was conducted to test the performance of the proposed method. The numerical results show that the three-dimensional positioning precision can reach approximately 0.4 m with combined GPS + GLONASS and approximately 0.2 m with combined GPS + GLONASS + Galileo + BeiDou.

scholarly journals ANALISIS SISTEM MONITORING KEAMANAN SERVER DENGAN SMS ALERT BERBASIS SNORT

2020 ◽  
Vol 1 (1) ◽  
pp. 25
Author(s):  
I Komang Krisna Ade Marta ◽  
I Nyoman Buda Hartawan ◽  
I Kadek Susila Satwika
Keyword(s):  
Real Time ◽  
Short Message Service ◽  
Security System ◽  
Short Message ◽  
Important Thing ◽  
Ddos Attack ◽  
Network Load ◽  
Message Service

AbstrakKeamanan server merupakan hal penting yang perlu diberikan perhatian lebih saat melakukan konfigurasi server. Pada umumnya serangan yang terjadi pada server diketahui setelah terjadinya kegagalan pada server dalam memberikan layanan. Pada penelitian ini, dibangun sebuah sistem keamanan server yang dapat melakukan monitoring pada sebuah server ketika terdeteksi adanya aktivitas yang tidak wajar. Pemberitahuan akan dikirimkan melalui SMS (Short Message Service) ke handphone Administrator jaringan. Sistem yang dibangun melakukan pendeteksian intrusi pada server secara realtime menggunakan SNORT. Ketika terjadi akses yang tidak wajar pada server, maka SNORT akan mendeteksi dan mengirimkan informasi terjadinya aktivitas yang tidak wajar ke Administrator jaringan. Sistem ini diujikan dengan lima jenis serangan yakni PING Attack, DoS/DDoS Attack, Port Scanning, Telnet Access dan FTP Access. Parameter yang diamati pada penelitian ini adalah beban aktivitas yang terjadi pada sumber daya server meliputi CPU, Memory (RAM) dan beban jaringan. Hasil penelitian menunjukkan bahwa saat terjadi upaya serangan terhadap server, SNORT dapat menghasilkan alert yang akan disimpan pada log sekaligus dikirimkan ke handphone Administrator melalui SMS. AbstractServer security is an important thing that needs to be given more attention when configuring a server. In general, attacks that occur on the server are known after a failure on the server in providing services. In this study, a server security system was built that could monitor a server when an unusual activity was detected. Notifications will be sent via SMS (Short Message Service) to the network Administrator's smartphone. The system is built to detect intrusions on the server in real time using SNORT. When improper access occurs on the server, SNORT will detect and send information about the occurrence of unusual activity to the network Administrator. This system is tested with five types of attacks namely PING Attack, DoS / DDoS Attack, Port Scanning, Telnet Access and FTP Access. The parameters observed in this study are the activity load that occurs on server resources including CPU, Memory (RAM) and network load. The results showed that when an attempt was made to attack the server, SNORT could produce alerts that would be stored in a log as well as sent to the Administrator's smartphone via SMS.

scholarly journals GNSS-Warp Software for Real-Time Precise Point Positioning

2015 ◽  
Vol 50 (2) ◽  
pp. 59-76 ◽  
Author(s):  
Hadaś Tomasz
Keyword(s):  
Real Time ◽  
Precise Point Positioning ◽  
Static Mode ◽  
Time Service ◽  
The Real ◽  
North East ◽  
Satellite Geometry ◽  
Point Positioning ◽  
Performance Validation ◽  
Mode A

Abstract On April 1, 2013 IGS launched the real-time service providing products for Precise Point Positioning (PPP). The availability of real-time makes PPP a very powerful technique to process GNSS signals in real-time and opens a new PPP applications opportunities. There are still, however, some limitations of PPP, especially in the kinematic mode. A significant change in satellite geometry is required to efficiently de-correlate troposphere delay, receiver clock offset, and receiver height. In order to challenge PPP limitations, the GNSS-WARP (Wroclaw Algorithms for Real-time Positioning) software has been developed from scratch at Wroclaw University of Environmental and Life Science in Poland. This paper presents the GNSS-WARP software itself and some results of GNSS data analysis using PPP and PPP-RTK (Real-Time Kinematic) technique. The results of static and kinematic processing in GPS only and GPS + GLONASS mode with final and real-time products are presented. Software performance validation in postprocessing mode confirmed that the software can be considered as a state-ofthe- art software and used for further studies on PPP algorithm development. The real-time positioning test made it possible to assess the quality of real-time coordinates, which is a few millimeters for North, East, Up in static mode, a below decimeter in kinematic mode. The accuracy and precision of height estimates in kinematic mode were improved by constraining the solution with an external, near real-time troposphere model. The software also allows estimation of real-time ZTD, however, the obtained precision of 11.2 mm means that further improvements in the software, real-time products or processing strategy are required.

scholarly journals Real-Time Global Ionospheric Map and Its Application in Single-Frequency Positioning

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1138 ◽  
Author(s):  
Liang Zhang ◽  
Yibin Yao ◽  
Wenjie Peng ◽  
Lulu Shan ◽  
Yulin He ◽  
...  
Keyword(s):  
Real Time ◽  
Total Electron Content ◽  
Precise Point Positioning ◽  
Single Frequency ◽  
Electron Content ◽  
Vertical Total Electron Content ◽  
Total Electron ◽  
Time Service ◽  
Point Positioning ◽  
Raw Observations

The prevalence of real-time, low-cost, single-frequency, decimeter-level positioning has increased with the development of global navigation satellite systems (GNSSs). Ionospheric delay accounts for most errors in real-time single-frequency GNSS positioning. To eliminate ionospheric interference in real-time single-frequency precise point positioning (RT-SF-PPP), global ionospheric vertical total electron content (VTEC) product is designed in the next stage of the International GNSS Service (IGS) real-time service (RTS). In this study, real-time generation of a global ionospheric map (GIM) based on IGS RTS is proposed and assessed. There are three crucial steps in the process of generating a real-time global ionospheric map (RTGIM): estimating station differential code bias (DCB) using the precise point positioning (PPP) method, deriving slant total electron content (STEC) from PPP with raw observations, and modeling global vertical total electron content (VTEC). Experiments were carried out to validate the algorithm’s effectiveness. First, one month’s data from 16 globally distributed IGS stations were used to validate the performance of DCB estimation with the PPP method. Second, 30 IGS stations were used to verify the accuracy of static PPP with raw observations. Third, the modeling of residuals was assessed in high and quiet ionospheric activity periods. Afterwards, the quality of RTGIM products was assessed from two aspects: (1) comparison with the Center for Orbit Determination in Europe (CODE) global ionospheric map (GIM) products and (2) determination of the performance of RT-SF-PPP with the RTGIM. Experimental results show that DCB estimation using the PPP method can realize an average accuracy of 0.2 ns; static PPP with raw observations can achieve an accuracy of 0.7, 1.2, and 2.1 cm in the north, east, and up components, respectively. The average standard deviations (STDs) of the model residuals are 2.07 and 2.17 TEC units (TECU) for moderate and high ionospheric activity periods. Moreover, the average root-mean-square (RMS) error of RTGIM products is 2.4 TECU for the one-month moderate ionospheric period. Nevertheless, for the high ionospheric period, the RMS is greater than the RMS in the moderate period. A sub-meter-level horizontal accuracy and meter-level vertical accuracy can be achieved when the RTGIM is employed in RT-SF-PPP.

On Beidou’s Short Message Service-Based Data Transmission Solution

2015 ◽  
Vol 12 (9) ◽  
pp. 2556-2565
Author(s):  
Wei Wang ◽  
Tianhe Chi ◽  
Qinge Wu ◽  
Wenfang Cheng ◽  
Zengan Deng ◽  
...  
Keyword(s):  
Data Transmission ◽  
Short Message Service ◽  
Short Message ◽  
Message Service

A SMS-Based Real-Time Device Monitoring and Abnormality Recovery System for Computer Rooms

2011 ◽  
Vol 121-126 ◽  
pp. 3750-3754 ◽  
Author(s):  
Chung Chiang Hu ◽  
Shing Han Li ◽  
Tien Wei Tsai
Keyword(s):  
Real Time ◽  
Monitoring System ◽  
Text Messaging ◽  
Short Message Service ◽  
Monitoring Systems ◽  
Short Message ◽  
The Real ◽  
Recovery System ◽  
Message Service ◽  
Reasonable Price

The equipments in computer rooms are complicated in nature. Many factors may influence their normal operations, for example: voltage, temperature, humidity, and the normalcy of systems. It would be prudent to have a monitoring system to prevent from unpredictable problems. Most monitoring systems in the market can only issue alarms in abnormal situations and then analyze the aftermath. They are also expansive and lack the ability for distant instant control. To tackle this problem, after our successful and practical experiments, we utilize GSM text messaging ability (i.e. SMS, short message service) and make distant monitoring possible. The monitoring system is established with a reasonable price that is well below current market. With this system, the manager/administrator can monitor the real-time status of equipments in computer rooms, send control commands through SMS and then get them executed to solve the problems instantly and effectively.

Precise Point Positioning Model Using Triple GNSS Constellations: GPS, Galileo and BeiDou

2016 ◽  
Vol 10 (4) ◽  
Author(s):  
Akram Afifi ◽  
Ahmed El-Rabbany
Keyword(s):  
Real Time ◽  
Urban Areas ◽  
Precise Point Positioning ◽  
Convergence Time ◽  
Dual Frequency ◽  
Post Processing ◽  
International Gnss Service ◽  
Time Service ◽  
System Bias ◽  
Point Positioning

AbstractThis paper introduces a comparison between dual-frequency precise point positioning (PPP) post-processing model, which combines the observations of three different GNSS constellations, namely GPS, Galileo, and BeiDou and real-time PPP model. A drawback of a single GNSS system such as GPS, however, is the availability of sufficient number of visible satellites in urban areas. Combining GNSS observations offers more visible satellites to users, which in turn is expected to enhance the satellite geometry and the overall positioning solution. However, combining several GNSS observables introduces additional biases, which require rigorous modelling, including the GNSS time offsets and hardware delays. In this paper, a GNSS post-processing PPPP model is developed using ionosphere-free linear combination. The additional biases of the GPS, Galileo, and BeiDou combination are accounted for through the introduction of a new unknown parameter, which is identified as the inter-system bias, in the PPP mathematical model. Natural Resources Canada’s GPSPace PPP software is modified to enable a combined GPS / Galileo / BeiDou PPP solution and to handle the newly inter-system bias. A total of four data sets at four IGS stations are processed to verify the developed PPP model. Precise satellite orbit and clock products from the IGS-MGEX network are used to correct of the GPS, Galileo and BeiDou measurements. For the real-time PPP model the corrections of the satellites orbit and clock are obtained through the international GNSS service (IGS) real-time service (RTS). GPS and Galileo Observations are used for the GNSS RTS-IGS PPP model as the RTS-IGS satellite products are not available for BeiDou satellites. This paper provides the GNSS RTS-IGS PPP model using different satellite clock corrections namely: IGS01, IGC01, IGS01, and IGS03. All PPP models results of convergence time and positioning precision are compared to the traditional GPS-only PPP model. It is shown that combining GPS, Galileo, and BeiDou observations in a PPP model reduces the convergence time by 25 % compared with the GPS-only PPP model.

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