Monitoring of Open Pit Mines using Combined GNSS Receivers and Robotic Total Stations

Department of Mining Engineering

Dr. T .Thimmaiah Institute of Technology

K.G.F, Kolar, Karnataka - 563120

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• Arun Maria Raj
• Abin T George
• Adarsh R Krishna

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CONTENT

• This presentation illustrates how ‘Global Navigation Satellite Systems’(GNSS) receivers and robotic total station instruments can be combined to provide fully automated, accurate, efficient and cost-effective survey monitoring system for large open pit mines which often reach sizes of 2km.

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EARTH WITH ITS  SATELLITES

GOD GAVE US 1 SATELLITE WE MADE IT 6000 !!!

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Acronyms

• G.N.S.S-- Global Navigation Satellite Systems
• G.P.S------Global Positioning System
• I.N.S------ Inertial Navigation System
• A.T.R------Automatic Target Recognition

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WHAT IS GNSS ?

• It is a network of 4 satellites
• GPS – USA,
• GLONASS  – Russia (Globalnaya Navigatsionnaya 
• Sputnikovaya Sistema) ,
• Compass – China, 
• Galileo - European Community and Japanese.

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• **IRNSS—Indian Regional Navigational Satellite System 
• Which will be functional by 2014

3 SATELLITES FOR TRIANGULATION, 1 SATELLITE FOR ACCURACY

• Devices that use GPS work by receiving signals from special satellites which orbit the earth twice a day at an altitude of 13000 miles

HOW DOES THIS WORK ?

FOUR IMPORTANT THINGS

• Position on earth
• Orientation relative to earth’s Centre
• Map projection
• Precisely engineered sensor

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1) Position on Earth

• Satellites continuously emits 2 pieces of information
• Time & co-ordinates
• GPS receivers use the information to do special calculation called Triangulation
• The receiver compares the time difference of signal sent to signal received. This gives the distance
• The G.P.S Receiver needs to get signal from 3 satellites to calculate latitude and longitude and if it gets signal from 4th satellite, it gives the altitude .

2) Orientation relative to earth’s Centre�

• Inertial Navigation System gives you the pointing direction
• Inertial measurement unit is the base on which the sensors works.
• It is usually mounted on the sensor

3) Map Projection

• The information collected by the sensor that is Geographical co-ordinates and Orientation of picture🡪 Cartesian co-ordinates

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• 3-D to plane

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• Why?
• Distance
• Area
• Shape
• Scale
• Volume
• Slope

4) Precisely Engineered Sensor

• Inside geometry of the sensor or camera. 

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• Internal Co-Ordinate system for every single pixel (up to 5 microns)

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PRACTICAL IMPLEMENTATION

• DEVOLPMENT IN SURVEYING

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• Manual-Months
• Arial photography-Weeks
• GNSS- Hours

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Explanation

• For every object you see in the picture you can measure its location on earth so you don’t have to send someone to the field to gather ground points which will take months .then we enhanced to Arial triangulation methods which used to take weeks
• GNSS allows us to make high accuracy maps within hours

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Total Stations

• A total station is an electronic/optical instrument used in modern surveying.

It allows the operator to control the instrument from a distance via remote control. It eliminates the need for additional staff member�

• Robotic Total Station

Robotic Total Stations-Working in action

• It must be placed on a level surface
• In this video, we can observe working of robotic total stations without additional staff member

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Collocated Prisms and GNSS Antennas with Free Station

• 2 or 3 reference points are to be mounted with the prism �
• These measurements are used in free stations for determining the position and orientation of total station

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• If any reference points are unstable GNSS antennas are used

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• This step up is slightly complicated

Advantages of G.N.S.S over Total Station

• Does not require line of sight to control points
• The reference point can be located kilometers away from the
• unstable mine area
• Measurement is continuous and works in all weather
• Relatively simple setup for the GNSS receivers
• (no measurement hut required) compared to total stations
• Very low maintenance costs
• Post processing using hours of data can increase precision and accuracy to the millimeter level

Disadvantages of G.N.S.S

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• An open sky view is required or otherwise the system can be affected by outages causes by insufficient tracked satellite. This problem is eliminated by using receivers that measure to multiple satellite systems (i.e.
• GPS and GLONASS)
• Nearby machinery can cause reflected signals to reach the antenna resulting in so-called multipath errors. However, this effect can be reduced with careful site selection, use of multipath reducing antennas and appropriate data processing techniques
• Increases in the number of sensors requires more power and communications

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DOUBTS ARE WELCOME !