Training program on GPS & GPS Based Survey Techniques Organized by:

1. Training program on GPS & GPS Based Survey Techniques Organized by: Urban and Rural Planning Discipline Khulna University, Khulna Conducted by: ENTECH LOGISTICS & Data Experts (Pvt) LTd. Period : April 5, 2012 to April 7, 2012 Location : Khulna University, Khulna

2. Training program on GPS & GPS Based Survey Techniques ENTECH LOGISTICS AT A GALANCE Official Name : ENTECH LOGISTICS LTD. Established on : JANUARY 2000 Type of Activities : SUPPLIER Field of expertise : Instrument, Equipment Software in the Field of Scientific Research, Industry, Education, Land Survey, Hydrogrpahy, Oceanography etc. Address : Office Suit # 13-D, Hometown Complex (Level-14) 87 New Eskaton Road, Dhaka-1000. Phone: 9336876, 9331852, Fax: 9336903 Mobile: 01819-245609, 01730441795 E-mail: entech@bdmail.net

3. Training program on GPS & GPS Based Survey Techniques Data Experts (datEx) at a Glance Official Name : Data Experts (Pvt) Ltd. Established on : November 2000 Type of Activities : Consultancy Services Field of expertise : GPS technology, All sort of GPS Based engineering survey All sort of digital mapping, GIS, MIS, Urban planning, Architectural design and Construction Supervision etc. Address : House 25/3, Road 15 (new) (old 28), Dhanmondi R/A, Dhaka-1209, Mobile: 01711822117, 01711822118 email: datexbd@gmail.com, datex.survey@gmail.com

4. Training program on GPS & GPS Based Survey Techniques Trainer: 1. Md. Rafiqul Islam, Director Technical, Data Experts 2. Md. Mesbah Uddin, Managing Director, Entech Logistics 3. Md. Hamidul Haque, Survey Supervisor, Data Experts

5. Training on GPS & GPS Based Survey Techniques • Global Positioning System (GPS) • Introduction and Brief description of GPS system and Survey techniques • GPS Satellite • Ground Control Station • GPS Receiver • 2. Types of GPS Receiver • DGPS • RTK GPS • Beacon GPS receiver • Handheld GPS

6. Training on GPS & Total Station • Optical and Electronic Digital Systems • 3. Total Station (TS) (TOPCON GTS-223/3000) • Physical Feature Survey (Position & Alignment of Point, Line, Polygon/Area) • Spot/Land Level/Contour Survey • Cross Section Survey • 4. Optical Level (TOPCON) • BM Carry/BM Check Survey • Cross Section Survey • TS and Other Survey Support

7. What is GPS Global Positioning System • A Satellite Based Positioning System with Global Access • Worldwide all-weather radio-navigation and positioning • GPS uses satellites (man-made-stars) as reference point to calculate position to a matter of metre or a centimetre. • Very soon GPS will become a basic need as like telephone.

8. Type of Satellite Positioning System NAVSTAR Global Positioning System – GPS (USA Military Controlled) GLONASS GLObal NAvigation Satellite System (Russian Military Controlled) Galileo Global Navigation Satellite System – Galileo (EU Civilian Controlled)

9. Type of Satellite Positioning System

10. GPS – Some Background NAVSTAR: NAVigation Satellite Timing and Ranging Merging of two military programs in 1973 Naval Research Laboratory- TIMATION Program Air Force- 621B Project First test Satellite Launched in 1978 Operational Satellites began Launching in 1989 Total System Managed by the US Department of Defence

11. GPS Segments The Total GPS System consist of 3 Parts As: Space Segments – Satellites Control Segments– Ground Control & Monitoring Stations User Segments – GPS Receivers

12. GPS Segments Space Segments Name : NAVSTAR (NAVigation Satellite Timing and Ranging) Manufacturer : Rockwell International Weight : 1900 Ibs Size : 17 ft with solar panel extended Life Span : 7.5 years (after launching) Nos. Satellites: Launched 31 nos., Usable 30 nos Altitude : 10,900 nautical miles (20,200 km) No of Orbit : 6 orbit Orbit Period : 12 hours Orbit Plane : 55° to equatorial plane

13. GPS Segments Control Segments 5 ground-based Monitoring & Control Stations: Continuously tracking satellite movement and provide data to the Master Control Station. These are: Master control and Monitoring station: * Falcon AFB, Colorado Springs Monitoring stations are: * Hawaii * Ascersion Island * Giego Garcia* Kwajalein

14. GPS Segments User Segments Various civilian and military receivers of GPS on land, sea and in the air. GPS receiver having a small computer/processor that can receive the signal transmitted from satellite and calculate the distance of satellite from the GPS antenna by time ranging and then calculate its position. Type of GPS Receivers: In terms of frequency: Single Frequency And Dual Frequency Receiver In terms of Use : Autonomous, Differential GPS (DGPS) & RTK GPS

15. GPS Applications * Navigation, Aviation * Moving Object Tracking * Hydrographic/Topographic/Physical Feature /Landuse/Engineering Survey * Land development /Master plan etc. * Mapping * Oil and Gas Exploration

16. GPS Applications Cont: GPS Application * Dredging * Traffic Regulation * Machine Control * Intelligent Transport Systems (ITC) * Electronic Toll Collection (ETC), etc.

17. Accuracy of GPS Positioning accuracy of GPS ranges from ±20 meters to a few millimeters depending on the following criteria: * Type of GPS receiver used * Number of satellites received by the receiver * Technique, Mode and Methods used for calculating position * Measurement Planning

18. GPS Errors Sources • Satellite Ephemeris • Clock Drift (Accuracy of the clocks in satellite and receiver) • Ionospheric and Tropospheric delay • Selective availability (S/A) (Intentionally introduced error by DOD) • Dilution of Precession (DOP) (Satellite geometry)

19. GPS Errors Sources • PDOP: Position Dilution of Precision : HDOP, VDOP, EDOP, NDOP etc.) • Multi path (Satellite signals reflected from other surface close to the receiver antenna) • Receiver Noise (Error from bad receiver/low quality receiver) • Human Error (Errors occurred by Operators ) Cont: GPS Errors Sources

20. GPS Technology to Minimize the Errors Satellite ephemeris – Possible to minimize Clock drift – Possible to minimize Ionospheric and Tropospheric delay – Possible to minimize Selective availability – Possible to minimize Dilution of precession – Possible to minimize Multi path – Possible to minimize Receiver noise - Not possible Human error - Not possible

21. GPS Technology to Minimize the Errors DGPS - Differential Global Positioning System) and RTK-GPS- Real-Time Kinematic Global Positioning System These are different versions of GPS technology, each with its own range of applicability and accuracy level

22. DGPS –Technique Position Accuracy ± 1m Differential Global Positioning System (DGPS): Differential-is the difference between a GPS code position & a known position at a single receiver On-line Correction: Real-time correctionof code based position Real-time capabilitiespresumeradio linkbetween receivers Off-line Correction: Without Real-time capabilitiesi.e without radio link between receivers

23. Baseline Triangulation RTK –Technique Positional Accuracy ± 5mm Real-time Kinematic Global Positioning System (RTK-GPS) On-line Correction- Differential & On the fly Measurement Real-time correctionof code based position Real-time capabilitiespresumeradio linkbetween receivers Off-line Correction- Static & Kinematic Measurement Without Real-time capabilitiesi.e without radio link between receivers

24. Advantages of GPS Measurements/Survey • Highly accurate • Very fast • Line of sight not required • Can be used for a very long base line • Unified 3-dimensional global co-ordinate system • (x,y,z) output

25. Advantages of GPS Measurements/Survey • Digital/Computerized data storage, • processing facility • Digital output fully compatible with GIS • No accumulated error • Very less chance of human error

26. How GPS Works • The Basis of GPS is “triangulation” from satellites - It is a method of determining the relative positions of objects using geometry of triangles. • The GPS receivers measures the distance of satellites • - using travel time of radio signals from satellite to receiver antenna.

27. How GPS Works • To measure the travel time, GPS need very accurate timing • - which it achieves with a very high tech electronic pulse measurement techniques. • Along with Distance we need to know exactly where the • satellites are in space • - High orbit of satellites and carefully monitoring and controlling from ground control stations are responsible for that.

28. Use of GPS in various Survey works (Which is our main interest in this training) • Basically the GPS receiver is not a survey equipment rather than a positioning equipment. • We can only measure the position of a point on the earth surface, then using various technology we can use it for survey of Point features, Line features or Polygon features.

29. Use of GPS in various Survey works (Which is our main interest in this training) • Use of GPS in Various types of survey : Few of those are as • Physical features and Topographic survey • Point features such as Electric pole, Telephone pole, Tube well, or any small structure whose dimension is not required. • Line features such as alignment of road, khal, wakl_way, river bank line or any sort of linear features. • Poly line/Polygon such as Water bodies, Homestead, or any closed features. • Hydrographic survey : River cross section, Bathymetry etc.

30. Use of GPS in Topographic Survey • Preparation for Topographic survey with GPS • Selection of Reference Bench Mark • Two types of Bench Mark available in Survey of Bangladesh can be used as reference for any type of survey. • Type of Bench Mark • - Horizontal datum - With known Latitude, Longitude and Ellipsoidal height in WGS-84. • - Vertical datum - With known Reduced Level (Height above mean sea level) in mSOB or mPWD

31. Use of GPS in Topographic Survey Preparation for Topographic survey with GPS 2. Installation of Ground Control Point (GCP), Temporary Bench Mark (TBM) for survey works in the interested project area. 3. Static Baseline survey by RTK GPS on GCP/TBM point to accurately obtain the Coordinates of GCP/TBM points for further use (it as reference point of GPS and/or Total station.) 4. Process Static Baseline survey data, Prepare the GCP/TBM point list for total station survey.

32. Sample Pictures of reference BM Horizontal BM (With known Latitude, Longitude, Ellipsoidal Ht) (Established by JICA under SOB) Vertical BM (With known RL established by SOB)

33. Static Base Line Survey by RTK GPS • Pre-Survey Consideration : • Dual frequency antenna with ground plane could be used • to minimize multi-path effect. • At least one known point is required. • Accessibility to the reference station and the points to be • surveyed. • Coordinate of reference station. • PDOP mask • Elevation mask. • Experienced surveyor should be engaged

34. Equipment Checklist list for Baseline survey • All the survey equipment must be checked before launching for survey. • RTK GPS with following accessories • Data Logger/Laptop with survey controller software • Accessories: • GPS antenna with Ground Planes (in case of external antenna) • GPS antenna cables (in case of external antenna) • GPS Power cable (in case of external power) • Optical plummet/Tribrach • Tripod stand/Antenna mast/rod

35. Equipment Checklist list for Baseline survey • Accessories (cont): • Tripod stand/Antenna mast/rod • Hand held data logger • Battery • Battery charger • Height measuring rod • Antenna-Tribrach fitting bolt

36. Static Base Line Survey by RTK GPS(Positional Accuracy: ± 5 mm) • At least 2 RTK GPS Receivers are required for base line survey. • One receiver to be deployed on Base Station for collecting satellite data and calculating the position of the Base Point , and stores these data in the internal memory. • The 2nd unit to be deployed on New BM or TBM for collecting satellite data and calculating the position of the unknown point, and store these data in the internal memory.

37. Static Base Line Survey by RTK GPS(Positional Accuracy: ± 5 mm) • Both the receiver must be in operation simultaneously and collect satellite data at an interval of 10-15sec and for a period of 5-40 minutes depending on the nos of satellite availability.

38. Static Base Line Survey by RTK GPS(Positional Accuracy: ± 5 mm) • In the office the collected data from both the receivers are down loaded into the computer by Appropriate Software, and then process the Baselines. In this process the software calculates the quantity of error comparing the measured data and Actual Known values of Base point, then deducting this error to the rover’s data the final and accurate coordinates of unknown new points are obtained.

39. Establishment of Horizontal datum to the New BM by Baseline Survey Procedure by GPS Static Survey. Base/Reference Station Rover (New BM/GCP) station

40. Establishment of Horizontal datum to the New BM by Baseline Survey Procedure by GPS Static Survey. • During the setup of GPS on BM/GCP/Temporary • point, the antenna height from that point to be measured • by a measuring stick, and then input it along with BM no • or Point Name/ID to the GPS receiver through handheld • computer such as Data Logger or Laptop computer. • Static survey means the receiver will receive satellite data • and store them in it’s memory for a period of time (5- • 40min) without moving the antenna.

42. Thank You