Title of Invention	"A TRACKING SYSTEM FOR MONITORING AND CONTROLLING THE POSITION OF MOBILE UNITS"
Abstract	A tracking syhstem for monitoring and controlling the position of mobile units. It comprises a graphical work station (3), a network modem (4) to provide interface between the work station (3) and the vehicle (5) and broadcast differential corrections. A differential global positioning system receiver (1) to said corrections to network modem and nirdeshak to compute the position information.

Full Text

FIELD OF INVENTION This invention relates to a tracking system for monitoring and controlling the position of mobile units. Positioning information in today's world is of paramount significance and the information can be used in many different ways. The positioning information finds application in defence,industrial and transport sectors for effective depolyment of mobile units. Various technologies are used for getting positioning information based on the user needs. Defence and surveying applications require highly accurate position (cm level) information for deployment and asset management. Industrial and transport application require accuracy (1-5 meters) for effective resource utilisation and control of mobile units for trouble and congestion free operations. The system that monitors and controls the position of mobile units is known as vehicle tracking systems. A tracking system is an integrated system for positioning and control of the mobile units from a central station. Such a system finds use in various fields like police, fire department, transport companies, airport and open cast mines. Various technologies are used to implement such system to meet the user needs. The technology used varies from simple voice based communication dependent on the operator and supervisor to state of the art satellite communication to compute the position correctly and send them automatically to the central station. Typically in mines, vehicles play a critical role in transport of ore from shovels to crushers. The monitoring and control of vehicles is critical for the effective and safe operation of the vehicles in the mines. According to the invention, a tracking system for monitoring and controlling the position of mobile units comprising a graphical work station, a network modem to provide interface between the work station and the vehicle and broad cast differential corrections, differential global positioning system, DGPS receiver to said corrections and network modem and nirdeshak mounted on the vehicle to compute position information, transmit position and command type messages to the host. Presently in open cast mines dumpers and shovels are the mobile equipments that determine the productivity of the mines. The dumpers transport the ore from the shovel to the crusher bay and the shovels excavate and load the dumpers. The dumpers are capable transporting heavy loads per trips. So a marginal increase in number of trips per day results in higher revenues and faster return on investment. In order to achieve effective utilisation of the mobile equipments, the open cast mining industry utilizes various technologies to deploy the vehicles. It is known to have an operator dependent system which uses voice communication between the central station supervisor and the mobile vehicles to know the position and deploy them effectively. This system depends heavily on the vehicle operator to report position and the supervisor routes the vehicles the operater having a mental picture of the situation of the various mobile equipment's. Another form of operator dependent system uses data communication in the form messages from the operator to know the position. With thi» system, the operator informs the central station of his position by sending location/destination messages to the central station. The central station collects the location messages periodically from mobile equipment's and the central system based on the various location and status of the vehicles depalys them effectively. The disadvantage of this system is that it is to depend on the report of the operator in respect of the positon and the status of the mobile equipments. Further, they vehicle position is known only from few critical places as operator has difficulties in sending position information at regular intervals of 10 seconds. Further, the vehicle deployment programs do not work very well when the expected time of arrival of dumpers is not dynamically updated. The ETA based on distance and the average speed work fine under normal condition but during cogestion times the fail to work. It is also known to have an operator independent system in order to overcome the problems associated with earier system, an-operator independent system based beacons was developed. The system used radio based beacons placed at strategic location to report the vehicle position in the form of beacon to the central station. As the vehicle cross the beacons, The system in the vehicle gets the ID and transmits the ID to the central station. The central identifies the vehicle position from the ID. The system reported the vehicle position without operator help but the system is not real time, as this would require large number of bacons. Such large number of beacons create maintenance problems and when the mining area is changed, the beacons need to be redeployed leading to time consuming installation. The problem associated with beacon-based technology was overcome with the advent of Global Positioning system (GPS) based satellites. The system depends on satellites in space to compute position and the information can be sent at 10 seconds intervals to the central station. BRIEF DESCRIPTION OF THE INVENTION A tracking system based on differential Global positioning system, DGPS is proposed to overcome the difficulties experienced with present system and also meet future requirements. The vehicle tracking system is an integrated system for vehicle positioning and control movement from central control station. The vehicle tracking system (VTS) uses Differential Global Positioning System (DGPS), a derivative of GPS for position determination. Global Positioning System (GPS) is a constellation of 24 satellites orbiting the earth at an altitude of 20200 KM. The satellites orbits ensure visibility of 4-6 satellites at all times. The GPS receivers, mounted on a vehicle compute their position based on navigation messages received from the GPS satellite constellation. The GPS receivers use triangulation method to compute 3D position such as latitude, longitude and altitude using 4 satellites. The position accuracy using standalone GPS receiver is 100 meters. The accuracy is very much improved by Differential GPS received (DGPS) which eliminates major sources of error by applying differential corrections transmitted from a reference DGPS receiver. The traditional vehicle navigation systems are based on acquiring vehicle position by using onboard or externally installed devices like Odometers, compasses, gyroscopes, radio frequency receivers etc. The method that employs these tools for the purpose of vehicle positioning is called Dead Reckoning Methods. In Deed Reckoning Method, heading and distance sensors are used to measure the displacement vectors which are then used in a recursive manner to determine the current position of the vehicle, with a known starting position. However, accuracy of the Dead Reckoning Method of constantly degrading since error in all measurements accumulatively affect the current position estimation. But with the advent of DGPS position estimation. But with the advent of DGPS position determination now becomes more accurate than that provided by any other system. OBJECTS. OF THE PRESENT INVENTION The primary object of this invention is to propose an tracking system for vehicle positioning and control for the mobile units from central station. The requirement of the system is to ensure the mobile units can be monitored and effectively controlled to optimise the available resources and maximise the return on investment. Another object of this invention is to propose a system which provide the positional information in user friendly way and in real time mode for mobile units operating in harsh environment of mines. Yet another object is to propose a central control system, which uses alarms to indicate deviation from assigned routes followed by the mobile units, also information about the presence of unauthorized mobile units the restricted areas, the arrival of mobile units at the destinations and about the break down of mobile units According to this invention there is provided a vehicle tracking system comprising a graphical work station, a network modem to provide inter face between the work station and the vehicle and broad cast differential corrections, a DBFS receiver to said corrections to network modem and nirdeshak mounted on the vehicle to compute position information transmit position and command type messages to the host. In accordance with this invention the reference D6PS receivers is located at a known, surveyed location. This reference DBFS receiver computes its position from the visible 4-6 satellites, compares the computed position with the known position and sends the corrections to the mobile BPS receivers over Radio network. The mobile receivers apply the received corrections to the navigation messages received from the satellites and compute the accurate position. Thus by using Differential GPS receivers, position data accurate to 2—5 meters can be obtained. The position data obtained using DGPS receivers from mobile users is transmitted to the central control station over Radio network. Characteristic of the Radio network will depend on the geographic terrain and the frequency chosen. At the central control station, the position data from the mobile users is presented graphically on a Geographical Map. The central computer displays the vehicles in different colours based on the vehicle type, vehicle speed and the vehicle status for ease of identification. The central computer will have position information, the speed, the Expected Time of Arrival (ETA) and the Route of all the vehicles. The central computer uses alarms/events to indicate deviation from assigned routes followed by the vehicles, the presence/entry of unauthorized vehicles in the restricted area, the landmarks crossed en route, the arrival of vehicles at the destinations and the breaksdown of vehicles. Zoom, Pan and multiple windows feature of the Geographical Map or a particular area of the map is built in the VTS of the central computer for monitoring of large fleet and wide area that is typical of a city. The application software in the central computer uses point and click operations and alarms/events for ease of operation and provides query based interface to geographical information systems and other databases. The application software also supports configurable command type messages for communication with mobile users. A tracking system according to a preferred embodiment is herein described and illustrated in the accompanying drawings wherein - Fig.l shows the plan view of the system Fig.2 shows the plan view of the central control systems and Fig.3 shows the plan view of the nirdeshak Referring to the drawings particularly Fig. 1 the Differential Global Positioning System (DGPS) 1 for accurate vehicle positioning, a radio link 2 for position reporting and a central station to show vehicle position and control of movement. The system consists of a graphical workstation 3, a Network Modem 4 9057-25 to provide interface between graphical workstation 3 and the vehicles 5 and broadcase differential corrections, a DGPS receiver 6 Fig. 2 to send correction to Network Modem 4 and Nirdeshak 9057-20 mounted in the vehicles to compute position information, transmit position and 'command' type messages to the Host. Reference is now made to Fig. 2 at the central control station, the Graphical Workstation 3 system is using a high end PC with colour monitor and having networking capabilities. The Graphical Workstation software runs under Window 95/Windows NT environment. The software uses point and click operation with alarms and events to show vehicle position and control. The display has zoom and pan feature to display a certain part of the map. The software also initializes the DGPS receivers and the Nirdeshak 9057-20 in the vehilces. The Network Modem 4 9057-25 provides the interface to Radio link for communication with vehicles and the DGPS Reference receiver. The Network Modem can be programmed from the Graphical Workstation for position acquisition rate from every vehicle and the differential correction broadcase rate to the user Modems in the vehicle. The Network Modem ensures reliable transport of data to/from the vehicles using packetised protocol with error detection mechanism. The Nirdeshak 9057-20 is shown in Fig. 3 is provided in the vehicles provides an interface to the DGPS receiver in vehicles, the Radio link for communication, Keypad and LCD display. The Nirdeshak receivers differential corrections from the Network Modem and the correction received are applied by the DGPS receiver to compute the accurate position. The accurate position is sent to the Network Modem on request and is also displayed on the LCD for the vehicle user. The keypad in the Nirdeshak provide the vehicle user the facility to communicate with the Graphical Workstation. The system consists three sub system, namel a Nirdeshak in the vehicles, network modem at the central control station, and Graphical Workstation at the central control station. The Nirdeshak 9057-20 is typically located in the vehicles and it consists of 6 channel DSPS receiver, main PCB to interface to DGPS receiver, Radio, LCD and Keypad, a40x4 character LCD Display with backlighting, keypad, power supply, IP—43 enclosure—Dustproof and water splashproof, and memory. The network modem is located at the central control station and it consist of multichannel DSPS Reference Receiver, and main PCB to interface to Radio, Reference DSPS receiver and the Host, and power supply. The Graphical Workstation comprises a PC, SVSA color monitor, WINDOWS 95/WINDOWS NT Operating System, and Application Software for Vehicle Assignment and Navigation. WE CLAIM; 1. A tracking system for monitoring and controlling the position of mobile units comprising a graphical work station, a network modem (4) to provide interface between the work station (3) and the vehicle (5) and broad cast differential corrections, a differential global positioning system, DGPS receiver (1) to said corrections to network modem and nirdeshak mounted on the vehicle to compute position information, transmit position and command type messages to the host. 2. The tracking system for monitoring and controlling the position of mobile units as claimed in claim 1 wherein the graphical workstation comprises a PC, SVGA color monitor, windows 95/windows NT opening system and application software for vehicle assignment and navigation. 3. The tracking system for monitoring and controlling the position of mobile units as claimed in claim 1 wherein the network modem comprises of multichannel DGPS reference receiver and main PCB to interface to radio, reference DGPS receiver and the host and power supply. 4. The tracking system for monitoring and controlling the position of mobile units as claimed in claim 1 wherein the nirdeshak consists of 6 channel DGPS receiver, main PCB to interface to DGPS receiver, Radio, LCD and keypad, a 40X4 character LCD display with backlighting, keypad, power supply, IP-43 enclosure- Dustproof and water splash proof and memory. 5. A tracking system for monitoring and controlling the position of mobile units substantially as herein described and illustrated.

Documents:

2042-del-1998-abstract.pdf

2042-del-1998-claims.pdf

2042-del-1998-correspondence-others.pdf

2042-del-1998-correspondence-po.pdf

2042-del-1998-description (complete).pdf

2042-del-1998-drawings.pdf

2042-del-1998-form-1.pdf

2042-del-1998-form-19.pdf

2042-del-1998-form-2.pdf

2042-del-1998-form-26.pdf

2042-del-1998-form-3.pdf

2042-del-1998-form-4.pdf

2042-del-1998-form-5.pdf

2042-del-1998-gpa.pdf

2042-del-1998-petition-137.pdf

2042-del-1998-petition-138.pdf