SUG532 - Advanced Geodesy Final Report

MARA UNIVERSITY OF TECHNO OGY Fieldwork Report BACHELOR OF GEOMATIC AND SURVEYING SCIENCE (AP220) Comparison Between Conventional Method ADVANCED GEODESY (SUG532) and Single & Dual PS Frequency Method ___________________________________ __________________________________________________ __________________

1.0

INTRODUCTION

Global Positioning System (G S) is a space-based radio navigation system that provides reliable positioning, navigation, and timing services to civilian users on a continuous worldwide basis freely available to all. For anyone with a GPS receiver, the system will provide location and time. GPS provides accur ate location and time information for an unli ited number of people in all weather, day and night, anywhere in the world. The GPS is made up of three p rts: satellites orbiting the Earth; control and m nitoring stations on Earth; and the GPS receiver owned by users. GPS satellites broadcast si nals from space that are picked up and identified by GPS receivers. Each GPS receiver the

provides three-

dimensional location (latitude, longitude, and altitude) plus the time. This system consists of three s gments: the space segment, the control segm nt, and the user segment. •

The space segment consists of a nominal constellation of 24 operating satellites that transmit one-way signals that give the current GPS satellite position and time.

•

The control segment consists of worldwide monitor and control stations that maintain the satellites in their proper orbits through occasional command maneuver s, and adjust the satellite clocks. It track

the GPS satellites, uploads updated navig tional data, and

maintains health and status of the satellite constellation. •

The user segment consists of the GPS receiver equipment, which rec ives the signals from the GPS satellites and uses the transmitted information to cal ulate the user’s three-dimensional position and time.

There are also several method on how to observe the satellite. The most p pular method of observing satellite today is static, kinematic, DGPS and etc. In our practical

e use the static

method. The basis of the GPS technolog is a set of 24 satellites that are continuously rbiting the earth. These satellites are equipped with atomic clocks and send out radio signals as to the exact time and their location. These radio signals from the satellites are picked up by the GPS receiver. Once the GPS receiver locks on to four or more of these satellites, it can trian ulate its location from the known positions of the atellites

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2.0

FIELD WORK AND LO ATION

GPS Observation, Traversing and Fly – leveling nearby the UITM Canseleri area

The green line is the GPS observation network and the red line is the traverse

3.0

OBJECTIVES

-

To learn and experience in observing satellite by using static method

-

To analyze the accuracy in determining coordinate of a position by usin GPS

-

To determine the different results between conventional and GPS obser ation data.

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4.0

INSTRUMENTS 4.1

Set of Traversing Equipment

Topcon Total Station is the most important instrument in survey works. It is used in traversing and to obt in bearings and distance. Prism used as a reflector unit wher e it will give the information about bearing and distance during the obs rvation 4.2

Set of Levelling Equipment

Lev lling Instrument is to measure the geodetic eight which taking a backsight and a foresight from the known height refe ence to a proposed site.

Lev lling Staff is Staff is to give a value of height which marked on it. 4.3

Set of GPS Single Frequency Equipmen

Magellan Promark 3 is single frequency GPS equipment. It allo s centimeter level static surveys.

4.4

Set of GPS Dual Frequency Equipment

Topcon HiPer Ga/Gb is model receiver has st ndard GPS satellite tracking capability with the added bonus o GLONASS satellite tracking upgradeability via OAF activation code. No hardware changes or modifications are required. U e the HiPer Ga s a cable free RTK base and rover system; or as two rover receivers from a fixed base station or a GNSS net ork system by way of radio or cellular communication.

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5.

PROCEDURES

5.1

Procedure of Traverse

i.

The traverse started with the total station is being set up at station 2 and the back bearing is station 1 and the front bearing is at station 3. The height of instrument and the back station and front st tion is taken.

ii.

The bearing, horizontal distance, vertical angle is observed with the bot face.

iii.

The procedure is repeated to the next station 4, 5, 6, 7, 8, 9, 10. unt il the traverse is close back to the line of to 2

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5.2

Procedure of GPS Obs rvation

a) Setup instrument at Station 1 and set as “Base” and another instrument at Station 4 and set as “Rover”. b) Configure both instruments for a static mode observation and meas re the height of antenna. c) After finish configuring for both instruments, wait for the receiver to det ct at the satellite at every quadrant. d) Observation can be started when the receiver displays the sufficient sa ellite signal. And the minimum is 4 satellit s required. e) Also aware about the G OP reading at the receiver, if the reading sh ws more than 6, we must wait until the re ding of the GDOP is less than 6. f)

The observation took for 20 minutes duration for each rover station before moved to another station.

g) The base is just remained at the Station 1 and the above process is repeated to the station 6, 7, and 10 befor e it is completed. ___________________________________ __________________________________________________ __________________ Page 7 of 22 of 22


5.3

Procedure of Levelling

a) Put the staff on the BM as a back sight b) Put another staff on stati n 1 as forward sight c) Stand the level instrume t in between both staff d) Make sure that the dista ce between staff and level for back and forwar sight are equal e) Then observe the staff at the back sight first and record the reading f)

Next observed for forwar d sight staff and record the reading

g) Move level on next point and put staff at station 1 as back sight and pu another staff on station 2 and observe h) Repeated the step f until the last station and then we must go back to the 1 station. i)

The same procedure go on and observation are made and record

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6.0

RESULTS

6.1

Distance Comparison BEARING AN

DISTANCE FROM CONVENSIONAL METHOD

FR

NORTHING

EASTING

TO

NORTHING

EASTING

BEARI G

DISTANCE

1

-11464.245

-22207.873

4

-11425.033

-22075.600

73 29 15.63

137. 963

1

-11464.245

-22207.873

6

-11539.944

-22028.846

112 55 1 .35

194.373

1

-11464.245

-22207.873

7

-11618.315

-22048.338

134 00 0 .91

221.786

1

-11464.245

-22207.873

10

-11540.230

-22149.832

142 37 3 .40

95.616

BEARING AND DISTANC

FROM GPS SINGLE FREQUENCY (PROMARK) METHOD

BASE 1 ROVER 10 ROVER 4 ROVER 6 ROVER 7

Conversion of the observe d Global WGS84 Coordinate to the Local Cassini Coordinate

FR

NORTHING

EASTING

TO

NORTHING

EASTING

BEARING

DISTANCE

BASE 1

-11464.245

-22207.873

ROVER 4

-11425.053

-22075.590

73 9 48.55

137. 967

BASE 1

-11464.245

-22207.873

ROVER 6

-11539.951

-22028.820

112 55 09.45

194.400

BASE 1

-11464.245

-22207.873

ROVER 7

-11618.336

-22048.309

134 00 01.23

221.821

BASE 1

-11464.245

-22207.873

ROVER 10

-11540.215

-22149.771

142 35 28.22

95.641

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BEARING AND DISTANCE FROM GPS DUAL FREQUENCY (TOPCON) M ETHOD


Conversion of the observe d Global WGS84 Coordinate to the Local Cassini Coordinate

FR

NORTHING

EASTING

TO

NORTHING

EASTING

B ARING

DISTANCE

* BASE 1

-11465.518

-22207.332

ROVER 4

-11426.337

-22075.042

89 55 17.79

132.290

BASE 1

-11465.518

-22207.332

ROVER 6

-11541.238

-22028.284

11 55 25.19

194.401

BASE 1

-11465.518

-22207.332

ROVER 7

-11619.622

-22047.755

13 00 01.53

221.840

BASE 1

-11465.518

-22207.332

ROVER 10

-11541.495

-22149.231

14 35 39.10

95.646

* The Observation 1 – 4 is a mistak . The station 4 was being observed not at the sam

station with the

previous observation.

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THE BEARING AN D DISTANCE COMPARISON FROM ALL METHO S

FR

TO

METHOD

INSTRUMENT

BEARI G

DISTANCE

1

4

Traverse

TOPCON Total Station

73 29 1 .63

137. 963

GPS Static Single Fr quency

PROMARK GPS

73 29 4 .55

137. 967

GPS Static Dual Fre quency

TOPCON GPS

89 55 1 .79

132.290

Traverse


112 55 1 .35

194.373


PROMARK GPS

112 55 0 .45

194.400


TOPCON GPS

112 55 2 .19

194.401

Traverse


134 00 0 .91

221.786


PROMARK GPS

134 00 01.23

221.840


TOPCON GPS

134 00 01.53

221.840

Traverse


142 37 3 .40

95.616


PROMARK GPS

142 35 2 .22

95.641


TOPCON GPS

142 35 3 .10

95.646

1

1

1

6

7

10

* The Observation 1 – 4 is a mistak . The station 4 was being observed not at the sam

station with the

previous observation.

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6.2

The Elevation Height C mparison

THE ELEVATION HEIGHT (REDUCED LEVEL) FROM CONVENSIONAL METHOD ( LY-LEVELLING) FR

EVELATION

TO

ELEVATION

DIFFERENC S

(Stn)

(Reduced Level)

(Stn)

(Reduced Level)

(Meter)

1

42.731

4

31.111

11.260

1

42.731

6

40.965

1.766

1

42.731

7

52.407

-9.676

THE ELEVATION HEIGHT (ELLIPSOIDAL) FROM GPS SINGLE FREQUENCY MET OD (PROMARK)


FR

EVELATI N

TO

(Ellipsoidal Height)

ELEVATION

DIFFERE CES

(Ellipsoidal Height) 11.72

1

39.066

4

27.346

1

39.066

6

37.162

1.904

1

39.066

7

48.551

-9.48

1

39.066

10

58.923

-19.857

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THE ELEVATION HEIGHT (ELL IPSOIDAL) FROM GPS DUAL FREQUENCY MET OD (TOPCON)


FR

EVEL TION

TO

ELEVATION

DIFFERENCES

1

38. 52

4

27.051

11.701

1

38. 52

6

36.893

1.859

1

38. 52

7

48.284

-9.532

1

38. 52

10

58.641

-19.889

THE ELEVATION HEIG T DIFFERENCES COMPARISON FROM ALL METHODS FR

TO

ME HOD

INSTRUMENT

DIF ERENCES

1

4

Fly - Levelling

Levelling

11.260

GPS Static Single Frequency

PROMARK GPS

11.720

GPS Static Dual Frequency

TOPCON GPS

11.701

Fly - Levelling

Levelling

1.766


PROMARK GPS

1.904


TOPCON GPS

1.859

Fly - Levelling

Levelling

-9.676


PROMARK GPS

-9.485


TOPCON GPS

-9.532

Fly - Levelling

Levelling

No available


PROMARK GPS

19.857


TOPCON GPS

19.889

1

1

1

6

7

10

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7.0

DISCUSSIONS

While finishing this fieldwork, we had same problem which are:

-

Based on data above, it showed that there are differences readin

value between

conventional method an single frequency GPS method (L1) and dual frequency GPS method (L1 & L2). These sequences may occur based on several factor s: 1.

While observing by using total station, errors occur due to h man error and environmental error.

2.

We might not accurately stand the GPS and total station right on he station point. For example for the tation 4 of GPS dual frequency observation, we are mistakenly set up the rover at th wrong point. Then we cannot get the appropriate result.

3.

Instead for the leveling we cannot reach to the station 10. It is b cause since the station 10 is on the car park, so when is the time we do the leveling, It has been placed with a car. So we had to leave the station.

-

We are not familiar with he GPS instrument, and we take much time t understand and studying the function and how to uses the GPS instruments.

-

Weather conditions also affect our project work because we have n t been properly studied and understood bout GPS. But, after our lecturer explains that we can do GPS observation in all conditi n of weather, then finally we do it although it is raining.

-

Error in booking is also ne of our problems in finishing the fieldwork. his is because if we do a booking wrongl , the data cannot be process perfectly. So, we do the leveling twice and do a proper booking on the next observation.

-

We are also not familiar with the GPS processing software of GNSS and the Topcon Tools. This is our first time using it and it takes a lot of time and tries to get a better result.

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8.0

CONCLUSION

It can be conclude that GPS syste

accurately can determined the coordinate of a poi t. Generally it can

be said that GPS receiver pairs ar set up over stations of either known or unknown location. Typically one of the receivers is positioned over a point whose coordinates are known (or ave been carried forward as on a traverse), and t e second is positioned over another point whos e coordinates are unknown, but are desired. Both

PS receivers must receive signals from the sa e four (or more)

satellites for a period of time that can range from a few minutes to several hours, depending on the conditions of observation and preci ion required

The Station occupation time is dep ndent on baseline length, number of satellites obse rved, and the GPS equipment used. In general, 30 m in to 2 hr is a good approximation for baseline o ccupation time for shorter baselines of 1 - 30kilometer s.

For the satellite visibility requirements, the stations that are selected for surv y must have an unobstructed view of the sky for a t least 15 deg or greater above the horizon durin g the "observation window." An observation window is the period of time when observable satellites are in the sky and the survey can be successfully conduct ed.

It is critical for a static survey bas line reduction/solution that the receivers simultan ously observe the same satellites during the same time interval. For instance, if receiver No. 1 obser ves a satellite set during the time interval 1,000 to 1, 00 and another receiver, receiver No. 2, observes that same satellite set during the time interval 1,100 to 1,300, only the period of common observation, 1,1 0 to 1,200, can be processed to formulate a correct ve ctor difference between these receivers.

In data post-processing, after the observation session has been completed, the rec ived GPS signals from both receivers are then proces sed (i.e., "post-processed") in a computer to calculate the 3D baseline vector components between the t o observed points. From these vector distances, local or geodetic coordinates may be computed and/ or adjusted. Mean while, in Receiver Operation and Data Reduction a specific receiver operation and b aseline data post-processing requirements are v ery manufacturerdependent. The user is strongly advised to consult and study manufacturer's o erations manuals thoroughly along with the baseline ata reduction examples.

The accuracy of Static is the most accurate and can be used for any order survey.

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SUG532 - Advanced Geodesy Final Report

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