SVY2301 / E4006 AUTOMATED SURVEYING SYSTEMS

1. SVY2301 / E4006AUTOMATED SURVEYING SYSTEMS Revision

2. Developments in Total Stations • Some of these developments include: • Development of Electronic Angle Measurement • Axis compensation • Motorisation and robotics • Developments in onboard software • Storage media and memory management • Developments in onboard software

3. Developments in Electronic Angle Measurement • Traditional system of angle measurement required the use of micrometers to read and interpolate the inscribed glass plate of theodolite. • Electronic Angle Measurement is now generally completed by one of two techniques: • Incremental Measurement, or • Absolute Measurement

4. Developments in Electronic Angle Measurement –Axis Compensation • automatic axis compensation corrects for errors in tilt in the horizontal and vertical axes. • Conventional systems used a plate bubble for the horizontal levelling and a pendulum sensor for the vertical axis compensator. • Electronic tilt sensors are usually liquid type compensation systems with either: • Magnetic detection or • Photodiode detection

5. Developments in Electronic Angle Measurement –Single Axis Compensation • Corrects for the tilt in the vertical axis.

6. Developments in Electronic Angle Measurement –Dual Axis Compensation • Dual Axis compensation corrects for • the inclination of the vertical axis in the direction of pointing, and • in the direction of the trunion axis. • axis produces errors in horizontal angles particularly in steep vertical sights.

7. Developments in Electronic Angle Measurement –Dual Axis Compensation

8. Developments in Electronic Angle Measurement –Motorised Total Stations • Motorised systems are characterised by: • Horizontal and vertical servo motor • Motors operate at high (course) and slow (fine) speeds • No tangent screws required • Very good for setout of points • Price approx $12-$16K

9. Developments in Electronic Angle Measurement –Self Tracking Total Station • The self tracking systems allow the automatic tracking of a prism. • Basic motorised system plus • Laser tracking system parallel to lens system • Track at high speeds • Automatic search routine when lock is lost • Focus not required • Faster and more accurate then human pointing • Can operate at night or low light conditions • Inbuilt communications to indicate that system is reading • Approx cost $17-$25K

10. Developments in Electronic Angle Measurement –Robotic System • Robotic system is the next step up from the self tracking system and includes all the features of a self tracking system plus: • Robotic software • Telemetry link • Remote control unit with key pad entry • Requires only one person • Surveyor may require assistance when placing pegs • Approx cost $30 -$40K

11. Developments in Electronic Angle Measurement –Reflectorless Total Stations • Developed to allow measurement to virtually any surface without the need to utilise a prism. • Charcterised by: • Measure approx 80m w/o prism • Measure buildings and structures with one person eg tunnel profiling • +/- 3mm • limited by surface reflectance and light conditions

12. SVY2301/E4006 Electronic Data Recording

13. Objectives • explain in detail the purpose of an electronic data recording facility; • describe the components of an electronic data recording facility; • list and describe the essential features of an electronic data recording facility; • explain the meaning of typical specifications for a data recorder, given an appropriate specification sheet; • compare the features of one data recording with those of other facilities; and • describe the features and operation of one data recording facility the student has studied.

14. Purpose of an Electronic Data Recording • to receive digital data from electronic surveying equipment and store it in a secure and reliable storage medium. • to manually record all of the information normally recorded in a fieldbook; • to transfer stored digital data to a computer, an electronic surveying instrument or to a back-up storage device;

15. Purpose of an Electronic Data Recording (cont) • to transfer stored data, either formatted or unformatted, to a printer to obtain a hard copy of the data; • to edit data in a stored data file whilst maintaining the integrity of the data; • to control the operations of electronic surveying equipment by using the keyboard of the data recorder or by a program running in the data recorder;

16. Purpose of an Electronic Data Recording (cont) • to control data recording processes from the keyboard of an electronic surveying instrument; and • to complete all normal tasks efficiently whilst still allowing the user a degree of flexibility in the methods they use.

17. Features of an Electronic Data Recording FacilityEssential Hardware Features 1. Storage Capacity - one day’s fieldwork. 2. Recorded data should be secure against accidental loss. accidental keystrokes memory unable to be cleared until the data has been transmitted to another device

18. Features of an Electronic Data Recording FacilityEssential Hardware Features 3. Recorded data should be secure against accidental power failure. back-up battery system. the integrity of the data must remain intact • The ROM and RAM memories should be protected against interference from radio transmissions and other electromagnetic sources

19. Features of an Electronic Data Recording FacilityEssential Hardware Features 5. The power supply should be sufficient for at least one full day’s operation. • The data recording facility should be capable of being interfaced with all electronic surveying equipment. • The data recording facility should be capable of being interfaced with computing equipment.

20. Features of an Electronic Data Recording FacilityEssential Hardware Features 8. The data recording facility should have a full alphanumeric display. • The display should be visible in all daylight conditions • The recording facility should allow data to be recorded manually via a keyboard.

21. Features of an Electronic Data Recording FacilityEssential Hardware Features 11. The use of the data recording facility keyboard should not disturb the functions or accuracy of electronic surveying equipment

22. Features of an Electronic Data Recording FacilityEssential Software Features • logical, easily understood, flexible and efficient. • give alphanumeric prompts for information when in the data recording mode. • enable non-measurement information to be recorded.

23. Features of an Electronic Data Recording FacilityEssential Software Features 4. enable the efficient transfer of digital data from electronic surveying equipment. • enable the efficient transfer of recorded data to a computer • enable measured data to be recorded without any deterioration in accuracy. 7. enable recorded measurements to be tagged.

24. SVY2301/E4006 Field Coding Systems

25. Objectives • describe in detail the types of information recorded in a field book; • describe in detail, using examples where necessary, how these types of information can be coded in the field; • explain the different field coding systems currently utilised; and • describe the advantages and disadvantages of each coding system

26. Introduction • digital surveying equipment has eliminated the need to record field measurements in a fieldbook • measurements are recorded in an electronic data recorder at the touch of a button • the fieldbook becomes a purely descriptive or diagrammatic representation of the survey • the measurements recorded in a data recorder must be tagged in some way to enable them to be identified with the points that were surveyed • Generally the method used to tag measurements is known as a field coding system

27. The Functions of a Fieldbook Fieldbooks record a variety of information including: • Registration information • Measurement information • Descriptive information • Graphical information

28. Electronic FieldbookField Coding System Three field (feature) coding systems are detailed to illustrate the most commonly utilised systems. • simple numeric system, • simple mnemonic (alpha) system, and • comprehensive numeric system.

29. Electronic FieldbookField Coding System Simple Numeric System • consisted of two or three digit numeric codes which were related to a corresponding feature • the three digit code tended to evolve as the defacto standard for the numeric coding system

30. Electronic FieldbookField Coding System Simple Numeric System • Numeric codes are normally divided up into groups • A string code is normally used to distinguish graphical features and allow connectivity

31. Electronic FieldbookField Coding System Simple Numeric System • The advantages of this coding system are: • simple; - codes entered quickly; • compatible with nearly all total stations; and • it is very efficient. • The disadvantages are: • codes are not easily recognisable; • often require a code sheet to remember; and • the system does not allow for very complex graphical coding.

32. Electronic FieldbookField Coding System Simple Mnemonic (Alpha) System • precise alphanumeric feature coding method that can save typing time in the field • Only two or three characters are needed to describe the feature compared with a full description • utilized by the computer software to plot symbols or write descriptions on the feature points

33. Electronic FieldbookField Coding System Simple Mnemonic (Alpha) System A string code is normally used with the feature code to distinguish graphical features and allow connectivity.

34. Electronic FieldbookField Coding System Simple Mnemonic (Alpha) System • The advantages with this system are: • simple; - codes are easy to remember; and • very efficient. • The disadvantages are: • system does not allow for more complex graphical coding; • not all systems can use alpha codes; and • may be more time consuming to enter codes if instrument does not have an alpha keyboard.

35. Electronic FieldbookField Coding System Comprehensive Feature Codes • The Australian Survey Office (ASO) Feature Coding System • allows the surveyor to code each detail point under all four categories, i.e. feature description, feature type or material, vertical location and horizontal location • a main code/sub-code type, with each of the codes being numeric

36. Electronic FieldbookField Coding System Comprehensive Feature Codes

37. Electronic FieldbookField Coding System Comprehensive Feature Codes • The advantages of this system of coding are: • it is very comprehensive and allows for accurate description of features; and • there is minimal additional drafting in the office.

38. Electronic FieldbookField Coding System Comprehensive Feature Codes • The disadvantages are: • it is slow and complex in the field; • it always requires the list of codes in the field; and • the system is not particularly cost effective

39. SVY2301/E4006Automated Surveying Systems Field Operations and Techniques

40. Preparation and Planning (Office) • Understand the purpose of the survey • Gather relevant maps/plans of the area • Survey Control Search • Determine survey methodology based on desired accuracy and site topography

41. Preparation and Planning (Field) • Search area for survey control marks • Walk the area • Prepare a sketch • Locate survey control stations

42. Control Establishment • Horizontal • Ensure control is closed • Determine number of angles & distances to be observed to achieve desired accuracy • Vertical • Determine suitable levelling method

43. Field Pickup • set 0°00’00” to the RO, LISCAD will orientate the survey during the reduction • radiate to the required points • Maximum sight distance depends on required accuracy • Always check back to control or known points every 20 to 30 shots

44. Feature Location • Dependent on the purpose of the survey • May include • Trees > 0.15m diameter • structures ie buildings • fences • services - both underground and aboveground • topography

45. Topography • Purpose is to accurately describe the topography in the area • random spot heights • changes of grade banks, gullies • ensure breaklines are utilised

46. Operation of the Survey • Utilise sketch to assist in completing the designated area • Need to extend the area to ensure the contours are representative • Strings may be run successively or by using a cross-section method

47. Fieldbook Recording • Instrument heights • String numbers • Changes in prism heights • Errors in coding • Other miscellaneous graphical information

48. Checks • Always undertake checks • Use two RO points if possible so that you can check your coordinates and orientation • Check back to your RO’s every 20-30 shots • If you are traversing, pick up the same point from another station as a quality check

49. Processing and Reduction • Data Transfer • Reformatting • Processing • Editing and Computations • Creation of DTM and Contours • Volumes

50. Transfer of Data • Communication parameters • baud rate ( speed - bits per second) • E.g. 9600bits/sec • Communications port • E.g. COM 1, COM 2 • stop bits • Usually 1 or 2 • data bits (word length) • Usually set to eight • Parity (error checking) • Usually set to none