GPS system and its application in mining
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The document discusses the Global Positioning System (GPS). It provides details on: - How GPS uses 24 satellites to determine accurate 3D positions anywhere on Earth. - The three segments that make up GPS - the space segment of satellites, control segment of monitoring stations, and user segment of receivers. - How GPS uses triangulation of distance measurements from multiple satellites to calculate a user's precise location, velocity, and time.
GPS system and its application in mining
- 4. The Global Positioning System (GPS) is a satellite-based Navigation system developed and operated by the US Department of Defense. GPS is the shortened form of NAVSTAR GPS. This is an acronym for NAVIGATION System with Time And Ranging Global Positioning System. GPS uses constellation of 24 satellites to determine the accurate three-dimensional position of the user on the earth. GPS was originally designed for military use at any time anywhere on the surface of the earth but soon after proposals it is made available to civilian users also.
- 5. The GPS project was proposed in 1973 to overcome the limitations of earlier navigation systems. First satellite was launched in 1978 but It became fully operational with launching of 24th satellite in 1995. Advances in technology and new demands on the existing system have now led to efforts to modernize the GPS system and implement the next generation of GPS III satellites. In addition to GPS of US, other systems are also in use or under development, like RUSSIAN’s - Global Navigation Satellite System (GLONASS) EUROPEAN’s - Galileo positioning system INDIA’s - Indian Regional Navigational Satellite System CHINA’s - Compass navigation system but these systems are suffered from incomplete coverage of the globe and failed to made them available for civilian users.
- 6. Trying to figure out where you are is probable man’s oldest pastime. Finally US Dept of Defense decided to form a worldwide positioning system. Also known as NAVSTAR ( Navigation Satellite Timing and Ranging Global positioning system) provides instantaneous position, velocity and time information.
- 7. Space Segment Control Segment User Segment
- 9. 24 GPS space vehicles(SVs). Satellites orbit the earth in 12 hrs. 6 orbital planes inclined at 55 degrees with the equator. This constellation provides 5 to 8 SVs from any point on the earth.
- 10. The control segment comprises of 5 stations. They measure the distances of the overhead satellites every 1.5 seconds and send the corrected data to Master control. Here the satellite orbit, clock performance and health of the satellite are determined and determines whether repositioning is required. This information is sent to the three uplink stations
- 11. The User Segment consists of all earth-based GPS receivers. The user segment is totally user community, both civilian and military.
- 12. The GPS uses technique of "triangulation" to find location. To "triangulate," a GPS receiver measures distance from the satellite using the travel time of radio signals. To measure travel time, GPS needs very accurate timing, which is provided by atomic clocks used in the satellites. Along with distance, we need to know exactly where the satellites are in space. This information is obtained by Almanac data transmitted by satellites. Finally we must correct for any delays the signal experiences as it travels through the atmosphere. To compute a positions in three dimensions. We need to have four satellite measurements. The GPS uses a trigonometric approach to calculate the positions
- 13. They are high- frequency, low- power signals transferred between the satellite and the receiver. They relay the information such as location to the receiver, who then makes a calculation.
- 14. (1) Pseudorandom code, which is the satellite’s ID. (2) Ephermis data, which shows the condition and time. (3) Almanac data, where the satellite should be in orbit at any particular time.
- 15. Triangulation is the mathematical principle that explains how GPS works. There are two types of triangulation: 2-D and 3-D. GPS uses 3-D triangulation. 3-D has the capability to tell altitude or height, while 2-D doesn’t have that capability.
- 16. Triangulation is what the receiver does after it gets the signal. The radio signals give it the three possible spherical locations. Then, with the triangulation principle in place, it determines where you are, your longitude, latitude and altitude.
- 17. Say you’re 10 miles from Satellite A. You are in a sphere with a radius 10 miles away from satellite A. If you’re 15 miles from satellite B, then there is another sphere drawn. And the same for a third satellite and its sphere. At the common point of the satellites is your location. A B C
- 18. There should be a point where all the spheres meet from the triangulation principle. Using the information from the radio signal and the triangulation, the receiver can determine your location on Earth with latitude, longitude, and altitude.
- 19. The receiver is somewhere on this sphere. Signal From One Satellite Signals From Two Satellites Three Satellites (2D Positioning) Three Dimensional (3D) Positioning TRIANGLATION
- 24. GPS is extremely easy to navigate as it tells you to the direction for each turns you take or you have to take to reach to your destination. GPS works in all weather so you need not to worry of the climate as in other navigating systems. The GPS costs you very low. The most attractive feature of this system is its100% coverage on the planet. It also helps you to search the nearby restaurants, hotels and gas stations and is very useful for a new place. Due to its low cost, it is very easy to integrate into other technologies like cell phone. This is the best navigating system in water as in larger water bodies we are often misled due to lack of proper directions. Accuracy can vary from milli meters to several meters depending on the technique that is used.
- 25. Satellite surveying can be a one-person operation with significant savings in time and labour. Operators do not need high levels of skill. Position may be fixed on land,at sea or in the air.
- 26. Surveying:-Most mines now use RTK GPS systems for surveying. GPS considerably speeds up the surveying process and reduces the time surveyors are in the field often in vulnerable locations. For example, because the GPS system gives an absolute position, the tedious process of establishing field control points is entirely eliminated.
- 27. Truck Fleet Management:-Many mines are fitting GPS systems to their trucks for fleet management purposes. Trucks can be assigned to different loading machines in real time to improve overall efficiency. A side safety benefit is that the central control station knows at all times the whereabouts of each truck in the fleet. Stand alone GPS is generally adequate for this task.
- 28. Hazard Avoidance:-GPS systems can be set up to warn the operator of site hazards. For example a hazard warning system has been set up as a trial on a dozer at the Gladstone Port Authority. Coal from this stockpile is reclaimed through feeders under the stockpile. The dozers push the coal into the feeders. Sometimes the coal bridges, creating a void above the feeder. If the dozer ventures onto the void it will collapse and potentially cause a very serious accident. The GPS system warns the operator when he is getting close to the feeder position. This is often hard to see when the stockpile is full of coal.
- 29. The dozer is fitted with a cab computer which shows the dozer in its true position on a map of the site. It is also fitted with a light bar. More lights progressively come on as the dozer approaches the hopper position. At one metre a warning sounds. For the accuracy required for this system DGPS is quite adequate–offering substantial savings over an RTK system.
- 31. Collision Avoidance:-Another possible use of GPS to enhance safety is in collision avoidance. If all mobile vehicles are fitted with GPS and telemetry systems, they can continuously report their position to a central control base. Software at the base can then analyse the data and warn when two vehicles are on a collision course, as is done with civilian air flights in crowded air corridors. Such a system is possible, but requires high bandwidth telemetry systems to poll all rovers on a rapid basis. This kind of arrangement would be especially beneficial in areas where light vehicles and high speed long distance ore haulers are mixed.
- 32. Vehicle Tracking and Dispatch:- The dump trucks’ positions obtained are sent to the central control station, where it is carried the dumping scheduling management. This application determines which material is loaded and sends information and instructions to be followed by the truck drivers, in order to guarantee that the assignments are followed and the materials are correctly collected from the correct ore block and dumped in the correct dumping location. GPS surveying:-The advantage of using GPS for surveying in open pit mining is that only a single surveyor is required, in opposition to the conventional methods. Monitor Drivers and Vehicles:- The sensors in the vehicle provide monitoring information of equipment’s, like for instance air pressure. These systems also provide sensors sent to a central control station. This system will allow for rapid intervention in case of problems.
- 33. Reliability:-The GPS system has been in place for a long period of time and has come to be relied on for many commercial purposes. On May 1st 2000, President Clinton removed the intentional degradation of GPS signals known as Selective Availability. A repeated theme of Presidential decrees on GPS has been to "encourage acceptance and integration of GPS into peaceful civil, commercial and scientific applications worldwide; and to encourage private sector investment in and use of U.S. GPS technologies and services." It is unlikely that the US will re-impose Selective Availability or otherwise disrupt the GPS system. The use of reference stations in either DGPS or RTK effectively negates the effects of Selective Availability.
- 35. Control of heavy machinery such as draglines, Control of bucket wheels and dozers, Drill guidance, Roads grading and maintenance, Fleet management systems for haul trucks and other vehicles tracking and dispatch, Asset tracking, for instance, of lighting plant and mobile generators, Guidance and control for drill rigs and explosive trucks, Access and zone control for visiting vehicles, Detecting dangerous driver behavior and Collision avoidance applications. Surveying crews can be reduced
- 37. The technology is very power hungry, most systems will only last 8-12 hours before needing a battery replacement or recharge. The GPS signal is unable to pass through solid structures so is unable to work Can be affected by large buildings and is typically unreliable in CBD areas.