CC BY
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REFERENCES
1. Sanz Subirana, J., Juan Zornoza, J.M., and Hernandez-Pajares, M. (2013). GNSS DATA PROCESSING. Volume I- Fundamentals and algorithms. ESA communications
2. Kaplan E.D and Hegarty C.J. (2006). Understanding GPS: principles and applications. 2nd edition. Artech House Publishers
3. Buist, P. J. and Imparato, D. Undifferenced and Single Differenced GNSS noise analysis through a constrained baseline vector. Available from: https://repository.tudelft.nl/assets/uuid:5e9bb0f0-4b39-4628.../308685.pdf
4. Borre, K., Strang, G., (2012). Algorithms for Global Positioning, Wellesley-Cambridge Press
5. Strang, G., Borre, K., (1997), Linear Algebra, Geodesy, and GPS, Wellesley-Cambridge Press
6. Borre, K., (2009), GPS Easy Suite II: Easy 12: LAMBDA Method, InsideGNSS. p. 48-52. (March/ April). Available from: www.insidegnss.com [Accessed: 20th, 23rd of March 2016]
7. Mikroelektronika, (2012), GPS-Click manual, [Online] Available from: http://www.mikroe.com/click/gps [Accessed: 22nd of March 2016]
УДК 621.396 Qu.eza.da. Gaibor D.P.
Samara National Research University, Samara, Russia
GNSS - BASED VEHICLE TRACKING AND EMERGENCY RESPONSE TIME SYSTEMS
The aim of this project is to design and develop a vehicle tracking and emergency response time system using multi-constellation GNSS (Global Navigation Satellite System) receiver, with high accuracy, reliability and integrity and to send the position information of vehicle using GSM (Global System for Mobile Communications) modem across the mobile network. Moreover, the proposed system is aimed to monitor vehicle movement and in emergency cases decrease the time response using an integrate system which receive the current position and with this position the system search the nearest response emergency center. Also this system will search the mobile units that are close to the emergency point. All this information will be shown in real time on the monitor agent with a message oof alert. We consider 3 methods to transmit the position received by GNSS antenna: first is using the Internet connection that will be used to save the current vehicle position every second in the data center and to get the location of the object by the monitor agent. It will permit to have a history path oof each vehicle, when the monitor agent could not get the current place. This history information will permit to calculate possible position according the last received position and speed. Second is using a SMS message with parameters like velocity, position and time and thirdly, the GMS modem will call to the emergency center, the telephony system (Asterisk VoIP system) will search the telephone number in the Data Base and it will send an alert to the agent monitor.
Usage of GNSS technology provides precise and reliable positioning information at cheaper cost and also, GSM network for sending vehicle track information is also an efficient means for exchange with the GSM modem between data base and the GNSS receiver in real-time.
Key words:
Multi constellation, GSM modem, real-time, accuracy, time response
Introduction
This project is divided into tree main blocks: the first part is related to GNSS multi constellation receiver with high accuracy, reliability and integrity to compute the current position of the vehicle, second - to the data transmission in real time across the mobile network using a GSM modem and finally to develop a software of 3 layers multi platform with different operation levels such as user application (smart phones, tablets and PC), agent monitor application/software (control of emergency messages and calls) and applications for the mobile units (police, ambulance, fire-fighters). These three points are closely related and work synchronously also they use a free VoIP (Voice Over IP) Service called asterisk.
Most of the available vehicles tracking systems use single constellation GNSS receivers for position computation that is transmitted afterwards over the Internet or mobile network. But the use of single constellation GNSS receiver has limitation in terms of reliability in case of satellite failures. In order to address this problem, I propose in this project to design a Vehicle Tracking and Emergency Response Time system based on multi constellation GNSS receiver that will be integrated with GSM Modem to send positional data over the mobile network. This system configuration improves the reliability as well as integrity of position computation and decreases the time response of emergency center.
Broadly speaking, we can classify vehicle tracking systems in to two types: passive and active tracking system: The passive vehicle tracking system stores the position information of vehicles into the internal memory and it will be downloaded to the data center in the offline for further monitoring. Whereas in active vehicle tracking system, position information will be sent in real time to the data center for online monitoring of vehicles.[1] Some of the active tracking systems use techniques for automated data transmission with ISO standard like SAE (Society of automotive Engineers), J1939 -
ISO (International Organization for Standardization) [5]. This standard provides a high-speed in the transmission of data and control functions in real-time. [5]. Some of these systems can be updated regularly online and setup new trajectory, new features and others parameters. This online dispositive sends all the data in real time and it permits to locate or to follow the trajectory with specific software.
Multi constellation receivers compute position based on the signals from multiple satellite constellations i.e. GPS, Galileo, GLONASS, and others. Multi constellation service provides reliable coverage for position computation anywhere around the world, because failure of few satellites will be compensated by the availability of other satellite constellations. Whereas, in case of single constellation service, failure of single satellite may lead to degradation in the position accuracy. Use of multi constellation has the following advantages: The accuracy of position increases with more visible satellites, the system is more robust, the coverage area is extensive and reliability increases. We can compute more precisely the position with availability of more number of satellites [1].
Architecture
The vehicle tracking and emergency response time system has the next architecture. Firstly, the GNSS receiver in the vehicle gets the data from the GNSS satellites and computes the position. This position information contains latitude, longitude, number of the satellite and time; we will use it in the format established by the National Marine Engineers Association (NMEA), also we will use algorithms to measure the position with the less grade of error, this information will be sent using GSM Modem across the mobile network to the data center where all the information will be saved. Finally, each user could see the tracks of vehicles in devices such as phones or computers, which can be further mapped to electronic maps to ease the user interface. Furthermore, the vehicle-tracking device permits to call and to send information about position to the Emergency Center and the
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monitor agent could track the current position, also the system will choose the closest Emergency Center and show the information of Emergency units near the accident. The emergency systems could be used in cell phones and it will be described in software.
GNSS multi constellation
Multi constellation receiver can access multiple satellites of different constellations, which permits to have more satellites available to improve the accuracy and positioning [6] when we compute the location of the vehicle.
When we speak about multi constellation, we speak about multi frequency. The frequency of GNSS operation has wide spectrum coverage in the L-band of 1-2GHz. These frequencies are in lower L-band and upper L-band and the different frequencies allocated for each constellation. Multi frequency reception has the following advantages: noise reduction, mitigation of multi-path propagation, significant improvements in measurements and position computation. And also, the dual frequency reception permits to remove ionosphere errors. [6]
We verify sky plot of multiple constellations such as GPS, GALILEO, BEIDOU and QZSS some of these constellations are not global coverage but in few years will have global coverage.
Data transmittion
The mobile network is widely available to transmit data around the world. It has an extensive coverage area with multiple antennas. This network is divided into cells. The cell signals are encoding with FDMA (frequency division multiple access) and CDMA (code division multiple access). [7]
The method to transmit data across the GSM mobile network is using GSM (Global System for Mobile Communications) modems, these modems work with technologies like 2.5G, 3G, HSDA plus, GPRS and others. Some of them are used to connect some devices to the Internet and transmit data, but other part is closely connected to the SMS messages, some of these GMS modems have components to receive calls, this components will be useful when the center of emergency contact with the driver.
The advantage of using GSM modems for transmitting of position data of vehicle tracking system is wide area coverage of GSM networks, the speed of transmission, and also standard around the world.
To transmit position data over the GSM modem has to follow some specific command format to operate and interact with other devices. The standard command structure used in GSM modem is AT-cmd Message.
The AT commands are used for different devices, like modems and mobile phones, some of them have a specific AT-Command. The AT commands depend of the GSM technology. [8]
There are some global AT commands used in all dispositive such as the following commands:
AT+CBC is to know the battery charge level and status.
AT+CMGS Send message.
AT+CMGR Read message.
AT+CMGW Write message.
The information received by GNSS antenna is passed to the GSM modem and this will send in the header with HTTP request (GET and POST), this information is the next: velocity, position, time and id device for example: www.gnsstrack-ing.com?sp=2 5&pos= 53.111132-43.433453&ti=2016-04-21-09:02:32&id=234D. This information is sent every second and the modem return an ACK (acknowledgement). In emergency case and if the mode returns an error when it tried to send the information using the Internet, the next option is to sent the information using the SMS (Short Message Service) and this message contains the same information. If this method fail we programmed a third option: the GMS mode will call
to the emergency number, the VoIP central receive the call and it executes a script and searches the number in the data base and sends an alert to the monitor agent.
Software
In this system we developed the three-layer model known as three tier architecture. It is divided into 3 main sections: the presentation tier interacts with the user and this layer should be friendly with the user and easy to use, the next layer is the logic tier, this layer is used for communication between layers, to do process such as logic, process, sub process and so on, finally the third layer is a data tier that is closely connected with the data base and storage, the information used by upper layers of logic and presentation tier.
This system is developed in java J2EE Java Platform Enterprise Edition) multi platform, the web server is Apache tomcat upload in CentOS system. The J2EE advantages are the following: Web service support, security, connexion with multiple systems, DB (Data Base) connexion, persistence, load balancing, OOP (Object Oriented Programming) and high performance.
User application
The user application is developed for android and IOS, the main screen has a button to request help to the Emergency center and four additional options for the user: first, to request the help of the police, second is related to the ambulance, the third is the fire-fighters and the last one is the emergency call directly to the Emergency center.
The second screen the cell phone is synchronized with the device into the vehicle, this screen shows the current position of the vehicle and information such as velocity, latitude, longitude, and time.
The user can see the current vehicle position in the web page using his/her user name and password. This web page shows the history of paths, configuration, notifications, and other options. The user can set his/her information such as email, telephone number, number in emergency cases.
Monitor Agent application
The monitor agent in the Emergency Center uses this web application to track the current vehicle position, this application shows an alert when some vehicle activates the emergency button or the user activates the application in the cell phone. This software tracks automatically the position and searches all information in its database besides this system does a position request of Mobile Units such as the police and shows in the electronic map the closest units to the point of emergency.
The monitor agent can call to the driver using the GSM modem inside the vehicle. The monitor agent can control alerts in the system, emergency calls, vehicle tracking and to assign resources (police, ambulance, fire-fighters). When the system can not get the current position it searches the last position saved in the database and to shows possible locations according to the information about velocity, trajectory and time.
Mobile Units Application
This application will be used by the Mobile Units (police, ambulance, fire-fighters). This application shows an alert in the main screen when some vehicle alarm is activated, it means that the Mobile Unit is close to the emergency site, the application shows the emergency point and the mobile unit position and the best way to arrive at that site.
This application contains other screen where the user could select whether they need support of the police, ambulance and fire-fighters or they need to call to the emergency center.
Database
The database used is MySQL, this is an efficient database used in web applications, business application, technological applications and so on. Some of its characteristics are the following: Multi-layer server with independent modules, MySQL can be use multiple CPUs, high standard of compression and indexation, it uses a very fast algorithm to access memory and locate the information, it can be used for temporary tables and so on. [15]
The database uses the entity-relationship model of the Data Base designed. This is a part of the global design of the multi constellation vehicle tracking. This current designee developed to save the data such as id track that is the unique identifier of each vehicle, time in which the data is transmitted, latitude, longitude and speed or velocity of the vehicle gave by the receiver device also the altitude. This information will be transmitted every second
across the mobile network. The user can see the information in real time through the Internet in the cell phone or computer with a username and password. This information will be able always available when the user needs it.
Conclusions
The GNSS multi constellation receiver for vehicle tracking improves the accuracy, reliability and integrity to compute the current position of the vehicle. In near future, most of the GNSS satellite constellations will have global coverage and this will permit GNSS receivers to work with large number of satellites with significant advantages described in this paper. Finally, this system helps to minimize the time response of the Emergency center give the more precise position of the vehicle and doing some process described in the software, we pretend to improve the time response in 40 %.
REFERENCES
1. WIKIPEDIA. (2016). Vehicle tracking system [Online] Available from: https://en.wikipe-dia.org/wiki/Vehicle tracking system [Accessed: 10th April 2016]
2. SAE International. (2016). SAE J1939 Standards Collection. . [Online] Available from: http://subs.sae.org//j1939_dl/ [Accessed: 25th January 2016]
3. YU-HSUAN, CH., et al. Development of a Real-time GNSS Software Receiver for Evaluating RAIM in Multi-constellation [Online] Available from: http://gps.stanford.edu/papers/Chen_IO-NITM_2 014_Multiraim.pdf [Accessed: 22th April 2016]
4. DEVELOPERSHOME. (2015). Introduction to AT Commands. [Online] Available from: http://www.de-velopershome.com/sms/atCommandsIntro.asp [Accessed: 2nd January 2 016]
5. SAE INTERNATIONAL. (2016) On-Highway Equipment Control and Communication Network [Online] Available from: http://store.sae.org/j193 9/contents/ [Accessed: 2nd January 2016]
6. NOVATEL. GLONASS. [Online] Available from: http://www.novatel.com/an-introduction-to-gnss/chapter-5-resolving-errors/multi-constellation-and-multi-frequency/ [Accessed: 8th March 2016].
7. WIKIPEDIA. (2015). Cellular network. [Online] Available from: https://en.wikipe-dia.org/wiki/Cellular_network [Accessed: 25th February 2016]
8. RAQUET, J., LACHAPELLE, G. (1996). Determination and Reduction of GPS Reference Station Multipath Using Multiple Receivers. [Online] Available from: http://plan.geomatics.ucalgary.ca/pa-pers/96gpsjor.pdf [Accessed: 27th January 2016]
УДК 621.396
Stepanova E. A., Shafran S. V., Kudryavtsev I. A.
Samara National Research University, Samara, Russia
GALILEO E5 RECEIVER FOR RELIABILITY IMPROVEMENT OF GNSS-BASED POSITIONING
The aim of the conducted research was to develop the part of Galileo E5 GNSS (Global Navigation Satellite System) signals receiver that will allow to estimate the position of the object with higher accuracy than receiver working with GPS signals. The task was to develop blocks for Galileo signals acquisition and tracking and to test them in order to show the operability of the developed blocks and the enhancement of the positioning accuracy. In Galileo constellation signals they introduced new type of modulation — Alternate Binary Offset Carrier modulation (AltBOC) [1] that provide highly accurate positioning under civilian control. Though GPS signal is available for civilian operation now it was initially meant for military purposes. The Galileo signal is meant for the civilian usage initially. Nowadays there is no fully operational Galileo receiver, only some blocks are developed by different researches, that is why this work is aiming at the development of such receiver.
Keywords:
Galileo signals, AltBOC modulation, acquisition, tracking, multipath
Introduction
The motivation for the development of the Galileo receiver is the growth of Galileo satellite constellation - now ESA (European Space Agency) has 11 operational satellites on-orbit and it is claimed that by the end of 2016 the constellation will enlarge up to 17 satellites [2]. This leads to the need of having the receiver that will be able to receive and process Galileo GNSS signals. The improvement of GNSS positioning will allow to use it more broadly in different areas, such as, airplane landing, car and trucks tracking, positioning in the emergency cases. Nowadays positioning error is not very good in some areas of the planet - it may be up to several tens of meters in urban areas or in forests, for example. In Galileo constellation the new modulation scheme [1] and the method of ionospheric corrections [3] are introduced to lessen the positioning error to the centimeters' level.
This work is focused on the Galileo E5 GNSS signal as the signal with the new type of modulation that will provide the more reliable positioning in comparison with the GPS signals po-
sitioning. We develop the acquisition and tracking blocks of Galileo E5 receiver taking for the basis the code developed by Kai Borre for GPS Software defined radio [4]. The novelty of the developments is that we designed blocks for Galileo GNSS signals acquisition and tracking that may be developed further by introducing the block of navigation solution into the fully operational Galileo GNSS signals receiver.
Research method
The work deals with the complex modulation scheme firstly introduced in the Galileo E5 signals - AltBOC modulation. The properties of this modulation are discussed in details in [1,5]. In [6] the multipath error envelopes for Galileo signals are discussed. Simsky et el. showed that in comparison with GPS signals that the error envelopes for all Galileo signals modulations are all inside the error envelope for GPS CA-code. The smallest error was for the Galileo E5 AltBOC modulation - it was within 50 meters for multipath delay. The results of the research conducted by Simsky et el. showed that the Galileo E5 AltBOC modulation was superior to any other type of modulation in terms of positioning accuracy.
