Geoid from Satlevel Collocation Model: A Case Study of Yanbu Industrial City, Saudi Arabia

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1 Internatonal OPEN ACCESS Journal Of Modern Engneerng Research (IJMER) Geod from Satlevel Collocaton Model: A Case Study of Yanbu Industral Cty, Saud Araba K. F. Aleem Department Of Surveyng And Geonformatcs, Abubakar Tafawa Balewa Unversty, Bauch,Ngera. ABSTRACT:-"Satlevel" Collocaton s a method of geod determnaton n whch the ellpsodal heght from any satellte based system s combned wth orthometrc heght from geodetc levellng to model the geod. Geod determnaton has been one of the problems of Geodessts. Several approaches has been adopted but the ntegraton of geodetc levellng and Global Navgaton Satellte System (GNSS), whch enables the geod to be determned n patches, s taken over from the emprcal geod determnaton. In ths work, "Satlevel" Collocaton model whch has earler been developed by the Author was used to generate geodal coeffcents n Yanbu Industral cty. The geodal coeffcents were used to predct the geodal values usng the user s nteractve computer program Orthometrc Heght on Fly. The program was used to compute the geodal undulaton of any geographcal locaton wthn the area. Statstcal analyses were carred out. The computed Satlevel Collocaton s results compared favourably wth sample results of the observed values. Ths method can be extended to other parts of Saud Araba and any other locaton. Keywords:- Geod, Satlevel Collocaton Geodetc levellng and GNSS I. INTRODUCTION The geod s the surface whch concdes wth that surface to whch the oceans would conform over the entre earth, f free to adjust to the combned effect of the earth's mass attracton (gravtaton) and the centrfugal force of the Earth's rotaton (Bomford, 1980). Specfcally, t s an equpotental surface, meanng that t s a surface on whch the gravtatonal potental energy has the same value everywhere wth respect to gravty. The geod surface s rregular, but consderably smoother than earth's physcal surface. Sea level, f undsturbed by tdes, currents and weather, would assume a surface equal to the geod when the observaton s carred out for a numbers of years. Determnaton of the geod has been one of major challenges of geodessts. Gravty data have been used n the past wth stokes ntegraton and other approaches. These methods are tme consumng, expensve and laborous. GNSS provde WGS 84 ellpsodal heghts and when compared wth orthometrc heght, from geodetc levellng, allows for the computaton of the geod, or the geod-ellpsod separaton n the regon of the survey (Aleem, 1996; Olaleye et al, 2010; Aleem et al, 2011). The development of the Satlevel method has been facltated by the mprovement n technology. The Global Navgaton Satellte System (GNSS) measurements are servng as mportant nput n geodesy and provdng new nsghts nto geod modellng. Wth GNSS, ellpsodal heght (heght above the ellpsod) can be computed drectly, whle the orthometrc heghts (heght above the geod) can be determned by geodetc levellng. The dfference between them s called geod heght or geodal undulaton or geod separaton (N). These heght dfferences were used to derve the geodal models called satlevel collocaton model (Aleem, 2013). The geod model wll gve geodal undulaton at every pont of observaton. Ths can be substtuted wth the ellpsodal heght from GNSS observaton to get the orthometrc heght has gven n Equaton 1.1: H = h - N (1.1) Where: H = Orthometrc heght h = Ellpsodal heght N = geodal ubdulaton II. AIMS AND OBJECTIVES The am s to determne the geod of the study area from data generated usng Satlevel Collocaton Model. The objectves are: 1. To acqure data for ellpsodal and orthometrc heght of the study IJMER ISSN: Vol. 6 Iss. 5 May

2 Geod From Satlevel Collocaton Model: A Case Study Of Yanbu Industral Cty, Saud Araba 2. To compute geodal coeffcents of the Satlevel Collocaton Model n the study area usng Least squares adjustment. 3. To determne the geod of the area usng satlevel collocaton model. III. LIMITATION OF THE STUDY The followng are the lmtaton of ths research: 1. The area of coverage s too small. 2. Automatc level was used to obtan orthometrc heght as aganst the use of Dgtal or Geodetc level. 3. The readngs were taken to 3 places of decmal as aganst 5 places of decmal requred by specfcaton for geodetc levellng. 4. Outler were not removed from the observaton The Study Area The study was carred out n Yanbu Industral Cty (popularly known as Yanbu Al-Sna'ya n Arabc whch lterarly means Industral Yanbu) n Madna Provnce of Saud Araba. The cty was establshed around 1975, located on the Coast of Red Sea about 350km North of Jeddah. Wth Lattude '57.840"N ( ) and longtude '39.000"E ( ) Fgure 1: Map of Saud Araba showng the locaton of Yanbu Industral cty Yanbu Industral Cty has a secton called the Royal Commsson (RC). Its resdents are mostly expatrates. RC Yanbu Exstng Area: 185 km² and RC Yanbu Expanson Area: 420 km². Fgure 2: The Exstng and land use Map of Yanbu Industral Cty. Source: RCJY (2012) The presence of ndustres such as the three ol refneres, plastcs facltes and several other petrochemcal plants n the exstng and expanson of Yanbu Industral Cty wll requre detaled map and updatng of the exstng map of whch geod determnaton have a promnent role to play. IV. MATERIALS AND DATA The equpment needed for the exercse are: GNSS recever and ts accessores to acqure data for ellpsodal heght Level and ts accessores to acqure data for orthometrc heght Computer and ts accessores for computaton and analyss Surfer software for plottng the contour Any software or program that can mplement least square adjustment to the soluton vector. In ths exercse Mcrosoft Offce excel was used for all calculatons, However Aleem, (2013) has IJMER ISSN: Vol. 6 Iss. 5 May

3 Geod From Satlevel Collocaton Model: A Case Study Of Yanbu Industral Cty, Saud Araba developed computer program for all the procedures Orthometrc Heght on Fly whch was used to valdate the results. V. METHODOLOGY 4.1 Data Acquston: Levellng operaton was carred out to obtan data for orthometrc heght. GNSS observaton was carred out to acqure data for geodetc coordnates whch ncludes the geodetc lattude, geodetc longtude and ellpsodal heght. Other relevant data such constant for the referenced ellpsod were collected from varous lterature and INTERNET webstes for data analyss and processng. 4.2 Data Processng: Levellng reducton was carred out, the reduced level were the orthometrc heght of each of the ponts reduced. GNSS observaton was processed to get the three dmensonal coordnates. These are the geodetc lattude (ϕ), geodetc longtude (λ) and ellpsodal heght (h), whch were used n satevel collocaton model. 4.3 Satlevel Collocaton Model: Satlevel Collocaton model was developed by Aleem, (2013), who gave the detaled of the dervaton. The model s of the form: N N A L 1 sn sn A A sn sn sn sn sn sn sn sn sn sn r (4.1) Where: N L s the long wavelength part of the geod undulaton n the area. A 1, A 2 and A 3 are the geodal coeffcents whch are unknown coeffcents to be determned. ϕ and λ are the WGS 84 geodetc coordnates (Lattudes and Longtudes) r s resdue at an observaton pont. The satlevel collocaton model geodal coeffcents of the area were computed usng least square adjustment observaton equaton method. The satlevel collocaton model geodal coeffcents were used to compute the geodal undulaton of each pont n the area, whch were connected to get the geodal surface. A user nteractve program called Orthometrc heght on Fly was desgned usng FORTRAN Powerstaton. The flowchart (Fgure. 3) for the program gves detaled procedure of ts usage. Orthometrc heght on the fly was desgned usng Mcrosoft FORTRAN PowerStaton. Fgure 3: Flowchart for Orthometrc Heght on the Fly Programs (Source: Aleem, 2013a): IJMER ISSN: Vol. 6 Iss. 5 May

4 Geod From Satlevel Collocaton Model: A Case Study Of Yanbu Industral Cty, Saud Araba VI. RESULTS AND DISCUSSIONS 5.1 Results: The GNSS data acqured from the feld were processed and the ellpsodal heghts were extracted from the processed result. Smlarly, the results of levellng operaton that was done were reduced and adjusted to gve the Orthometrc Heghts Pont Number Lattude Longtude Ellpsodal Heghts Orthometrc Heght (H) Observed Geodal Undulaton (Source: Aleem, 2013b): The data used for ths research acqured n Yanbu Industral Cty were used to plot chart (Fgure 4): The geodal coeffcents of Yanbu Industral Cty were computed usng least square adjustment observaton equaton as: N L = A 1 = A 2 = A 3 = (Aleem, 2013b) The results of the satlevel collocaton geodal undulatons were plotted nto chart (Fgure 5): The result of the satlevel collocaton orthometrc heght were plotted nto chart (Fgure 5): IJMER ISSN: Vol. 6 Iss. 5 May

5 Geod From Satlevel Collocaton Model: A Case Study Of Yanbu Industral Cty, Saud Araba 5.2 Dscusson Over Sx hundred geodetc coordnates and orthometrc heghts data were acqured. One hund red and ffteen of these data were randomly selected and used to determne the geodal coeffcents of the Yanbu Industral Cty. The ellpsodal and orthometrc heghts data were used to draw the chart shown n Fgure 4. In ths chart, ellpsodal and orthometrc heght follows the same pattern shows an ndcaton that the two are true representaton of the same terran. Olaleye et al (2010) also supported ths clam. The geodal coeffcents of Yanbu Industral Cty obataned n ths research can be used to compute the geod undulaton wth satlevel collocaton model for place around Yanbu Industral Cty/ Fgure 5 shows the geodal surface of Yanbu Industral Cty. In ths chart, the geodal Undulaton of 3 of the ponts was outrageous, whch s an ndcaton that, there was presence of outlers n the observatons. These observatons should have been removed because they are more than 3 standard devatons (Helan et al, 2004). Physcally, those bump exsts on ground as a result of excavatons around the areas. Ths a;s6 sh6es that the data s a true representaton of the area. VII. CONCLUSION AND RECOMMENDATION In ths study, levelled heghts were establshed along wth GPS observaton n some parts of Yanbu Industral cty to model the geod n the study area. We have coordnated some of the ponts collocated wth both GNSS and levellng n the area. 'Satlevel" Collocaton Model was used to obtan the geodal coeffcents. Wth these geodal coeffcents, t s possble to obtan the geodal undulaton of any other pont n the area usng the geodetc coordnates obtaned wth Global Navgaton Satellte recever. VIII. RECOMMENDATIONS The area of coverage needs to be extended and more data should be acqured to mprove the results. A local geod of Saud Araba s requred. REFERENCES [1]. Aleem, K. F. (1996): GPS and Remote Sensng of Envronment. The Graduate Surveyors. Journal of NISS Unversty of Ngera, Enugu Campus. 12(1) [2]. Aleem, K. F. (2013a): Adaptaton of a Global Orthometrc to a Local Heght Datum Usng Satlevel Collocaton Model. A Ph.D Thess. Deaprtment of Surveyng and Geonformatcs, Unversty of Lagos, Ngera. UNPUBLISHED [3]. Aleem, K. F. (2013b) Satlevel Collocaton Model for Adaptng GEM 2008 to Geod n Yanbu Industral Cty. Proceedng of 2013 Scentfc Assembly Internatonal Assocaton of Geodesy, Potsdam Germany, 1-6th September2013.Avalable onlne [4]. Aleem, K. F., J. B. Olaleye, O. T. Badejo and J. O. Olusna (2011). A Combnaton of Ellpsodal Heght from Satellte Method and Orthometrc Heght for Geod Modellng. publcaton of the Internatonal Global Navgaton SatelltesSocetyIGNSSwebste spx [5]. Aleem K. F. AlGhamd, H. and Khayyat M. M. (2013). Conventonal and Satlevel Collocaton Model for Producton of Contour Map: A case study of Yanbu Industral Cty. Coordnates Magazne. Vol. IX, Issue 10, October Avalable onlne: collocaton-model-for-producton-of-contour-map/ [6]. Bomford, G. (1980) Geodesy. 4th Edton. London: Clerendon press. Deakn R. E. (1996). The Geod, What s t got to do wth me?. The Australan Surveyor, 41(4): [7]. Helan, L. S., Y. Fukuda, and S. Takemoto (2004). Smulaton of the Indonesan Land Gravty Data Usng a Dgtal Terran Model Data. Earth Planets Space, 56(1): [8]. Olaleye, J. B., K. F. Aleem, J. O. Olusna and O. E. Abodun (2010). Establshment of an Emprcal Geod Model for a Small Geographc Area: A Case Study of Port Harcourt, Ngera. Surveyng and Land Informaton Scence. 70(1): 39-48(10) / /art00006 [9]. Royal Commsson for Jubal and Yanbu, Royal Commsson at Yanbu (2012). Annual Report of the Strategc Plannng & Investment Development Dvson Economc Plannng Department. [10]. Zaletnyk, P., L. Völgyes, and B. Palánczb, (2006). Approach of the Hungaran Geod Surface wth Sequence of Neural Networks. Research supported by the Hungaran Natonal Research Fund (OTKA), Contract No. T IJMER ISSN: Vol. 6 Iss. 5 May