GSSI (GNSS Simulation and System Integration) Technology

The research team in the GNSS simulation and System Integration Laboratory^* performs very dynamic research activities in the field of GPS and system integration, including:

• Modern positioning and navigation technology

  • GNSS (Global Navigation Satellite System)

  • INS (Inertial Navigation System)

  • Wireless communication system for seamless indoor and outdoor positioning and navigation

• High-precision positioning and navigation system

  • Single-baseline RTK (Real-Time Kinematic)

  • Network-based RTK

  • PPP (Precise Point Positioning)

  • Integration of GNSS and INS

• Practical solutions in scientific and engineering applications

  • Machine guidance and control: gantry crane auto-steering, autonomous lawnmower, unmanned ground/aerial vehicle (UGV/UAV)

  • Real-time remote monitoring: land slide monitoring at open pit mines, dam deformation monitoring, and structure vibration monitoring

  • Geo-spatial technology fusion

• GNSS simulation and software/hardware performance analysis

CFI (Canada Foundation for Innovation) Programs

In June 2004, the Canada Foundation for Innovation (CFI) notified Dr. Don Kim that funding for his research project had been approved. Dr. Kim has received the grant for his New Opportunities Fund Project entitled Remote-Controlled Autonomous GPS RTK System. The total project is valued at $453,560 with Dr. Kim receiving almost $181,500 from CFI.

GPS signal simulators, GPS receivers, data communication and network equipment, microcontroller training/development kits, RTK base station control equipment, and computers constitute the infrastructure for the project. The infrastructure enabled Dr. Kim to establish new research programs at UNB, including GPS signal simulation (GPS receiver and RTK system performance tests), system integration, broadband data communication, microcontroller applications (robotic and autonomous RTK system), and geo-spatial fusion (location-based service).

Over the five year lifetime of the research program, an enhanced RTK system will be developed with the capability to remotely control a machine (such as a gantry crane, or mining or construction equipment), autonomously operate a machine, provide location-based service over wired and wireless networks, and have demonstrated its use for ultra-high precision machine control, local deformation monitoring, long-baseline RTK, and satellite attitude determination. This practical system will have significant economic and safety benefits to Canadian industry through increasing productivity, expanding technology exports to overseas markets, reducing accidents, and improving safety.

The program will further enhance UNB's reputation as one of North America's leading centres for research on global navigation satellite systems. 

GPS Signal Simulation

The GPS signal simulator enables a research program that leads to a substantial study on the GPS receiver itself and various scientific issues related to the GPS observations such as atmospheric effects, satellite orbit pertubations, multipath, satellite and receiver clock performance, antenna phase centre variation, and carrier-phase wrap-up. The signal simulator enables the researchers to dramatically reduce the need for expensive and time-consuming field trials when testing, evaluating or qualifying GPS receiver equipment and RTK systems as well as simulating relatively inaccessible environments such as low-earth orbit for spaceborne applications.

Industrial requirements normally set a very high standard for prototype system development. Generally, such requirements are accomplished by system performance parameters such as integrity, continuity, accuracy and availability. Among these parameters, the risk associated with hardware equipment or software design failure is specified by an integrity parameter. The theory of hypothesis testing relates the integrity parameter to a Type II error (i.e., the case that we fail to reject a hypothesis when it should be rejected). When designing a practical RTK system according to industrial requirements, the Type II error should be minimized to improve the safety of the system. Large scale field tests should be carried out and a significant amount of test data should be analyzed to determine the integrity parameter. Although the other three system performance parameters – continuity, accuracy and availability – reflect different system requirements, extensive field tests and intensive data analysis are required to determine the values of the parameters.

The signal simulator provides a complete simulated RF environment for exercising and simulating navigation and positioning systems, making field test data from different environments available. It could also provide data for inaccessible or hard-to-access environments (e.g., space, sky, ocean, mountains, and hazardous places). This will provide deeper and wider GPS-related research opportunities such as a performance test of an RTK system under a high dynamic or space environment.

System Integration

Since the research program in the GSSI technology aims to develop a practical, high precision positioning and navigation system, a number of hardware components are being investigated, tested and integrated for a prototype system. The infrastructure enables the researchers to initiate a research program on hardware control, which offers a new research area in machine guidance and control. Hardware components to be studied through this program include GPS receiver, microcontroller (e.g., in-circuit emulator and programmer, programmable single board controller, PLC (Programmable Logic Controller), Ethernet-to-serial controller, and stepper motor controller), data communication and network equipment (e.g., twisted pair, fiber/coax, all fiber, and wireless), and multimedia devices (micro video camera and video transceiver). In addition, research on hardware interface for a real-time communication link between the RTK base station and rover through Ethernet, serial and parallel ports, USB (Universal Serial Bus), and Bluetooth is being performed.

Broadband Data Communication

The research program addresses broadband communication issues that are relevant both to the ubiquitous accessibility of the core infrastructure network and the interface/integration of various broadband access technologies. In most instances, the performance of an RTK system relies on the availability of real-time data communication. Therefore, establishing stable communication links is one of the major challenges in developing the system. Down-link (from the base station to the rover) RTK data rates can reach up to 69 Kbps at a 10 Hz update rate. Data up-link (from the rover to a monitoring centre) normally does not require such a high communication volume. As a result, the overall RTK data rate could be higher than 100 Kbps when a full data link (down- and up-link) is established.

Due to the high communication volume of the GPS data and multimedia, and considering further enhancement of the RTK applications in the near future, broadband access technologies rather than conventional UHF radio modems are inevitable to enable “last-mile” (i.e., the connection of homes, small businesses or work sites to the core infrastructure) access connectivity from the core infrastructure to end-user devices. To provide seamless RTK services for clients moving through different environments, multiple-mode communication approach switching communication links among different broadband access technologies available on-the-fly is appropriate.

There are many competing broadband access technologies to improve last-mile connectivity such as twisted pair, fiber/coax, all fiber, and wireless. At present, several broadband wireless technologies such as terrestrial broadcast, cellular, wireless LAN, bluetooth and satellite broadcast are used.

GPS Robotics (Microcontroller)

A microcontroller is an integrated circuit that is programmable. It is widely applicable to the automation and control field as a robotic controller or as a data collection sensor. The research program focuses on the use of microcontroller training/developing kits, including an in-circuit emulator and programmer; a single board controller programmable in a microcontroller language; and a tiny PLC. The following example development illustrates how a microcontroller (for robotic and autonomous systems) can be integrated into the RTK applications.

A gantry crane auto-steering system has been developed to improve container-handling productivity and operational safety at a busy port container terminal. This system is used for keeping a rubber tired gantry crane (RTGC) on a track – a line mark or electrical guide wire in the container yard. By keeping an RTGC on a track, the auto-steering system can prevent an RTGC from causing an accident such as hitting containers and the other cranes. Identifying the line mark and calculating the corresponding deviations (from the line mark) of the front and rear axles of an RTGC are essential for that purpose. In an automated system, a PLC is usually the central part of a process control system that comprises a group of electronic devices and equipment. With execution of a program stored in the program memory, the PLC continuously monitors the status of the system through signals from input devices. Based on the logic implemented in the program, the PLC determines which actions the output devices need to execute. In an RTGC auto-steering system, the calculated deviations (that is, the RTK solutions) of the front and rear wheels are fed into the PLC so that it can adjust the speed of the left and right wheels to keep the crane on track.

Geo-Spatial Fusion

The fusion of the RTK system with other geo-spatial technologies (e.g., digital maps, satellite or airborne images, and GIS) will enable a variety of location-based services (LBS). LBS is the ability to find the geographical location of the mobile device and provide services based on this location information. The concept of LBS came from the requirements of the U.S. cellular telephone network operators to provide emergency services by locating the user of the mobile device within 125 metres. It required wireless network operators to supply public emergency services with the caller location and call-back phone number. This induced the emergence of a new and dynamic field called LBS, where the service was based on the geographical location of the calling device. Furthermore, the developments in the field of positioning systems, communications and GIS fuelled the imagination of the industry people. This ability to provide the user with a customised service depending upon his geographical location could be used by telecommunication companies to provide services to diverse groups of users (e.g., restaurant locations for auto travellers).

In the days to come, LBS will benefit both consumers and network operators. While consumers will have greater personal safety, more personalized features and increased communication convenience, the network operators will address discrete market segments based on the different service portfolios. Location becomes more and more a strategic asset of wireless carriers. Leveraging this information enables the user to experience value-added services and the mobile network operator to offer differentiation and incremental profitability. The infrastructure will immediately enable the applicant to initiate a research program to integrate GPS technology, geo-spatial technologies, multimedia and broadband wireless communication.

Teaching

Quantitative Analysis in Geomatics

G

Fall 2003

(With Dr. Marcelo Santos), Department of Geodesy and Geomatics Engineering, University of New Brunswick, Canada

Surveying

3

Spring 1997

Departments of Civil Engineering, Ajou University,  Korea

Surveying Practice

3

Adjustment Computations

4

GIS

4

Elementary Surveying

3

Spring 1997

Department of Geo-Informatic Engineering, Inha University,  Korea

Geodesy

4

Advanced Surveying

4

Fall 1996

Departments of Civil Engineering, Ajou University,  Korea

Photogrammetry

4

Surveying

3

Spring 1996

Departments of Civil Engineering, Ajou University,  Korea

Surveying Practice

3

Adjustment Computations

4

Elementary Surveying Practice

3

Fall 1995

Departments of Transportation Engineering, Ajou University,  Korea

Introductory Remote Sensing

4

Fall 1995

Departments of Civil Engineering, Ajou University,  Korea

Material Mechanics II

4

Fall 1995

Department of Environmental Engineering, Seoul National Polytechnic University,  Korea

Material Mechanics I

4

Spring 1995