cos s Presentation Layout HIGH ACCURACY REAL-TIME DAM MONITORING USING LOW COST GPS EQUIPMENT

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Suggestions fo Futhe Woks Reda Ali, Paul Coss, and Ali Elshakawi GPS Vesus Conventional methods Conventional methods GPS Advantages High accuacy can be obtained High edundancy of obsevations Gives

1 HIGH ACCURACY REAL-TIME DAM MONITORING USING LOW COST GPS EQUIPMENT Pesentation Layout GPS in Engineeing Monitoing. GPS Caie Phase Multipath Eo Multipath Sideeal-day Coection Technique Poposed Technique fo using Low-Cost GPS in EM Initial Tests of this Poposed Technique Dam Monitoing with GPS Conclusions and Suggestions fo Futhe Woks Reda Ali, Paul Coss, and Ali Elshakawi GPS Vesus Conventional methods Conventional methods GPS Advantages High accuacy can be obtained High edundancy of obsevations Gives absolute displacements of selected points Dawbacks Need inte-visibility between stations Bad weathe conditions limit obsevations Ae labou intensive and equied skilful obseves Not all methods suitable fo eal time Advantages Inte-visibility not necessay Automated opeation- with high obsevation ate All weathe condition- in eal time Dawbacks High Cost!!! Low accuacy in eal time applications!!! S d V cos θ S Sd GPS Caie Phase Multipath Eo(1/4 S S α V cos( φ θ 0 α 1 S β V cos( φ ψ sin( β 1 α cos( θ α tan -1 α θ ψ ( 1.0 α cos( θ * π Path delay due to MP * ψ λ Geometic Aspects of Caie Phase Multipath ψ d 1 tan cosθ cosθ cos s θ ( φ s sin θ s φ θ s φ s φ θ GPS Phase Multipath Eo (/4 Chaacteistics of GPS Phase Multipath Highly dependant on Site location (Not educed though diffeential pocessing It can each magnitudes of 0.5 of wave length (nealy 5 cm of L1 caie Its value and shape depends on many factos such as: Antenna Reflecto distance Antenna Reflecto geomety Satellite Elevation Angle and Azimuth Signal Wave length Reflection Coefficient GPS Phase Multipath Eo (3/4 Chaacteistics of GPS Phase Multipath It has nealy zeo mean so it may be cancelled by aveaging the esiduals It has little effect on final accuacy of positioning fo a long peiod of obsevation, but it causes a disaste fo GPS eal time applications such as GPS Engineeing Monitoing It epeats itself evey Sideeal day (Mean Sideeal day 3h 56m 4s of mean sola day

2 GPS Caie Phase obsevation equation s s s s φ R C ( dt dt T s s s I λn M s s s s R ( X X ( Y Y ( Z Z Noise GPS phase Double Diffeencing Technique JK φ AB φ φ JK AB ( φ J A J φ B ( φ K A K φ B JK JK JK JK JK JK C ( Noise AB AB AB AB AB AB R f R c GPS Caie Phase Multipath Eo (4/4 Extaction of GPS Phase Multipath dt f c dt T I λn M j j f k k jk jk [& ρa dta & ρb dtb ] [& ρa dta ρb dtb ] λn AB MAB ε φ ABφ ec jk jk AB AB & c mult Multipath eo (m Multipath eo (m GPS Caie Phase Multipath Repeatability (1/ Double Diffeenced 6-15 Day 7 Januay 00 ± 7.4 mm G PS Time (Sec [G PS W eek 1148] Day 8 Januay 00 ± 7.8 mm - - Coelation Facto GPS Time Diff 8615 Day8 D ay8-day7 ±.6 mm afte ± second mm GPS G Time (Sec [GPS W eek 1148] Block Diagam of the Suggested Technique fo GPS Engineeing Monitoing Softwae (GPSEM (I Data fom pevious day (IV Quality Contol Pocess (CUSUM (II Sideeal day coection technique (III Kalman Filte Detected movements Data fom ecent day No I- Data Fom Pevious Day (1/ Compute Satellite Position Vaiance Covaiance matix Constuct Nomal Equation Is data sufficient Apply Kalman Filte Tansfe fom DD to SD Data Input Yes Initial Pocessing Steps Double diffeence Obsevation Equation Intege Ambiguity Fixing Is ambiguity fixed Output files E-N-UP file Multipath file Yes I- Data Fom Pevious Day (/ Fomat of Multipath file Appoximate Coodinates of Rove Station The Stoed Data fo Each Epoch : Time of obsevation and numbe of used satellites Fo evey satellite, data ae stoed in one single line: Satellite identifies numbe (PRN Satellite position coodinate in X-diection in WGS84 Satellite position coodinate in Y-diection in WGS84 Satellite position coodinate in Z-diection in WGS84 Residual of single diffeence L1 phase obsevations with espect to appoximate coodinates of ove station. Numbe used in the stochastic model indicates the stength of signal t II- Sideeal day Coection Technique (1/3 Estimation of Sideeal day time shift between two days (T Revolution Peiod of slave satellite is computed using Keple s thid law of planetay motion (t π 3 GM G M is the univesal gavitational constant is the mass of the Eath is the adius fom the cente of the Eath to the cente of the satellite. Evey GPS satellite makes two evolutions pe one day so T * t Seach though pevious day data in cetain seaching volume centeed by T, to find the time of epoch which gives the smallest distances between location of this satellite between the two days If this satellite does not exist in the stoed file, this satellite will not be used fo any futhe calculations

II- Sideeal day Coection Technique (/3 Computing the Rove station positions fo two days Fomation DD obsevation equations using data fom pevious day Fomation Weight matix of DD Phase obsevations DD(,1

Fomation of Nomal matix and solve fo position associated with thei covaiance matix using LS Technique Subtacting positions of two days movements and noise II- Sideeal day Coection Technique (3/3

Engineeing Object Coodinate System (EOS Along defomation axis e cosα sin α 0 E Pependicula axis n - sinα cosα 0 N UP diection up EOS 0 0 1 UP Local Tansfoming the diffeence between position and thei

3 II- Sideeal day Coection Technique (/3 Computing the Rove station positions fo two days Fomation DD obsevation equations using data fom pevious day Fomation Weight matix of DD Phase obsevations DD(,1 SD(... SD( 1 SD( DD(, L M C DD DD( i, SD( SD(i M M O M 0 SD( L L DD(,N1 one-way path between satellite and antenna i may be computed as the poduct of 3 functions such as: i F * 1 F * ( d / D F 3 F3 e Fomation of Nomal matix and solve fo position associated with thei covaiance matix using LS Technique Subtacting positions of two days movements and noise II- Sideeal day Coection Technique (3/3 Necessay Coodinate Tansfomations Tansfomation fom WGS84 to Local Coodinate System (E-N-UP E sin( λ λ 0 X Xo N λ sin( ϕ λ ϕ ϕ YYo UP λ ϕ λ ϕ ϕ ZZo Tansfomation fom Local Coodinate System (E-N-UP to Engineeing Object Coodinate System (EOS Along defomation axis e cosα sin α 0 E Pependicula axis n - sinα cosα 0 N UP diection up EOS UP Local Tansfoming the diffeence between position and thei covaiance matix fom WGS84 to Engineeing Object coodinate System (EOS EOS { R } WGS84 Q { R} { RT } EOS QWGS84 III- Kalman Filte Technique (1/ Equations 1- Pedict State Vecto Xˆ i ( φi -1Xˆ i -1( - Compute Covaiance matix of pediction C T X C X i C i ˆ φ i -1 φ ( 1 i -1 y i 1 3- Compute pedicted esiduals vi ˆ ( bi Hi Xi ˆ ( 4- Compute gain matix [ H i H ] T i -1 G i C xˆ i(- H T i C li C xˆ i(- 5- Update state vecto Xi ˆ ( Xˆ i (- Gi vˆi ( 6- Update state covaiance matix C X ˆ [ I - Hi]C i( Gi X ˆ i( Measuement Update Time Update III- Kalman Filte Technique (/ Constant Velocity Model State Vecto X T [ E N UP v E v N vup] T Coesponding tansition matix M I M S L L L S diag{} s diag{ α -1(1 t } T diag {} t diag { e α t} Covaiance of dynamic model noise 0 M T Q1 t SQ M S Q S 3 diag{ S} (-3 α t 4 e-α t e-α t / α3 Cy( ω L L L { } -α t -α t S 3 S3 diag S3 (1 e e / α Q Q S3 M S33 diag { } (1 - α t S 33 S 33 e / α If α is vey small due to long If α is vey lage due to coelation length shot coelation length 1 1 Q 1 t Q t 3 M Q t Q E Cy( ω L L L Cy(ω 0 Q 1 N 0 Q t M Q t 0 0 QUP IV- Quality Contol Pocess Contol chat Failue Detection and Identification (FDI Pocess Contol chat IV- Quality Contol Pocess ( CUmulative SUM Contol chat (CUSUM CUSUM Fist poposed by Page [1954] C n C n1 ( X n - µ C 0 0 S S ( X -µ / S0 0 n n 1 CUSUM Statistical Contol Limits n S i max[ 0, yi K S i 1 ] x i µ y 0 i S i max[0, - yi K S i 1 ] Chosen efeence o allowance value (K, decision inteval (H and Aveage Run Length (ARL K 0.5 fo ARL 500 H Decease the false alam ate by pushing the in-contol ARL out to1000 eadings, then the equied H would become 5.071

Location: Initial Test of the system(1/ UCL main libay oof Equipment: UCL main libay oof Two GPS Leica 500 - AT50 Base line length 81.

4 Location: Initial Test of the system(1/ UCL main libay oof Equipment: UCL main libay oof Two GPS Leica AT50 Base line length 81.7 m Peiod of obsevations: Days 69, 70, and 71, of 003 Nealy thee hous /day Obsevation ate 1 Hz, mask angle 7.5 degee Data Collection scenaio : Days 69 and 70 no movement Day 71 movement had been intoduced with cetain patten Along defomation axis (m Along defomation axis (m Initial Test of the system(/ Time Seies of Day71 Zone I Zone II Zone III RMS ± 3.6 mm Measued Coodinates Tue Coodinates GPS Time (Sec GPS W eek # 109 Zone I Zone II Zone III -0 RMS ± 1.6 mm Filteed coodinates Tue Coodinates -0 Delay of nealy 3 min GPS Time (Sec GPS Week #109 Monitoing Pacoima Dam with GPS (1/ PACOIMA DAM Monitoing Pacoima Dam with GPS(1 / Wate Level and Studying Cases Location : Califonia - USA Uses : Flood Contol- wate consevations GPS Opeato : SCIGN Baseline Length m DAM1 DAM Wate Suface Elevation (Feet Case Study I Case Study II Receive Ashtech Z- XII3 and Choke ing antenna Feb 16-Feb 17-Feb 18-Feb 19-Feb 0-Feb 1-Feb -Feb 3-Feb 4-Feb 5-Feb 6-Feb 7-Feb 8-Feb 9-Feb Local Time (Yea 000 Along defomation axis coodinates (m pependicula to defomation axis coodinates. (m UP coodinates (m Analyses on the Fist Case Study (1 / 5 Raw Coodinates Afte outlies Detection Day 15-Feb 5900 Day 16-Feb Day 17-Feb Day 18-Feb GPS Time (sec Day 15- Feb Day 16- Feb Day 17- Feb Day 18- Feb GPS Time (Sec Day 15-Feb Day 16-Feb Day 17-Feb Day 18-Feb Fom Phaaohs to Geoinfomatics : FIG Woking GPS Time (Sec Week 005 and GSDI-8 Caio, Egypt. Apil 16-1, 005 Along defomation axis (m Pependicula to defomation axis (m UP coodinates (m Day 15-Feb Day 16-Feb Day 17-Feb Day 18-Feb GPS Time (sec Day 18- Feb Day 15- Feb Day 16- Feb Day 17- Feb GPS Time (Sec Day 15-Feb Day 16-Feb Day 17-Feb Day 18-Feb GPS Time (Sec Defomation in UPdiection (m defomation in pependicula to defomation axis (m Defomation in along defomation axis (m Analyses on the Fist Case Study ( / 5 Sideeal day coection Kalman filte - - Sideeal-daycoections.5 minutes MAF Day 15-Feb 5900 Day 16-Feb Day 17-Feb Day 18-Feb GPS Time (sec - - Sideeal-day coections.5minutes MAF - - Day 15- Feb Day 16- Feb Day 17- Feb Day 18- Feb GPS Time (Sec Sideeal-day coections.5 minutes MAF Day 15-Feb 5900 Day 16-Feb Day 17-Feb Day 18-Feb GPS Time (Sec defomation in pependicula to defomation Defomation in UPdiection (m axis (m Defomation in along defomation axis (m Day 15-Feb 5900 Day 16-Feb Day 17-Feb Day 18-Feb GPS Time (sec Day 15- Feb 5900 Day 16- Feb Day 17- Feb Day 18- Feb GPS Time (Sec Day 15-Feb 5900 Day 16-Feb Day 17-Feb Day 18-Feb GPS Time (Sec

5 Analyses on the Fist Case Study ( 3 / 5 To assess the pecision of the system, we look at the behaviou of the system fom day to day, and also the factos that cause these movements between the two days.. The system is said to be pecise if it eacts in the same way unde simila conditions. The two possible factos that can cause dam defomation ae: an incease in wate level in the dam esevoi o change in tempeatue. The diffeence in wate levels between two successive days is in ode of 0.1 feet (i.e. 3.4 cm. This has no impact on the dam defomation. Tempeatue (C Analyses on the Fist Case Study ( 4 / 5 A c tu al te m p e atu e T em peatue diffeence -10 Day 15-Feb Day 16-Feb Day 17-Feb Day 18-Feb G P S T im e ( S e c The aveage of the diffeences in tempeatues between two successive days ae in ode of o C. The effect is negligible. Thee is no cause fo any movements to occu between any two successive days. The question now is: does the output fom the system eflect this eality? Analyses on the Fist Case Study ( 5/ 5 Type of time seies and Maximum µ Maximum analysis (mm (mm Raw Coodinates 0.6 ± Sideeal-day coections Kalman filte (eal-time 0.0 ± 0.1 The esults show no defomation is detected with high pecision in eal-time. The standad deviations of the time seies ae in ode of ±0.1 mm The behaviou of the dam fom day to day is consistent with the Geo-technical measuements within ± mm. Thus, high pecision can be obtained by applying the poposed system in such defomation monitoing applications. Along defomation axis coodinates (m Amplitude (m Day 19-Feb Analyses on the Second Case Study ( 1 / 5 Raw data fom 10 days Along defomation axis diection Day 8-Feb GPS Time (sec Fouie analysis E E E E E-0 Fom Phaaohs to Geoinfomatics : FIG Woking Week 005 and GSDI-8 Caio, Egypt. Apil Fequency 16-1, 005 (Hz Defomation at along defomation axis (m Analyses on the Second Case Study ( / 5 Afte sideeal day coections D ay 19-Feb Along defomation axis diection G PS Time (sec Day 8-Feb If the data shown is filteed, the esult will only be the defomation that occued between the two successive days. To ovecome this: The defomations ae consideed to be zeo on the fist day Fo any ecent epoch, the computed defomation values ae added to those in the file. The pocess is caied out fo the next epoch, and so on till the end. In othe wods, the output will be an accumulated time seies of the filteed defomation. Defomation at along defomation axis (m Analyses on the Second Case Study ( 3 / 5 Afte Kalman Filte Along defomation axis diection Day 19-Feb Day 8-Feb GPS Time (sec

6 Analyses on the Second Case Study ( 4 / 5 Defomation Consistency with the Wate Suface Elevation Defomation consistency with wate level Thee is a stong coelation ( 98% between the defomation occued along pinciple defomation axis and the wate suface level in the esevoi Analyses on the Second Case Study (5 / 5 Validation of the System Validation of GPSEM LEICA SKI-Po GPS softwae is used to pocess the data fo whole 4-hou to ovecome the poblem of multipath eo. The output is the thee coodinates in WGS84. These coodinates ae tansfomed to bing these coodinates in the same fame Defomations at along defomation axis (m Using Leica Ski-Po GPS softwae RMS ± 0.43 mm -6 Day 19-Feb Day 8-Feb GPS Time (Sec Conclusions (1 / 3 GPS ovecomes all conventional methods dawbacks, but it has its own. These dawbacks ae low accuacy in eal-time and high cost of the equipment The phase Multipath eo is the dominant eo that limits the implementation of GPS in eal-time EM applications The GPS phase Multipath eo is highly dependent on antenna eflectos, satellite elative geomety, and almost epeats itself evey sideeal day Conclusions ( / 3 It detects the movements occuing in engineeing objects by applying the sideeal-day coection technique fo phase GPS multipath eos, a Kalman filte and a Cumulative SUM (CUSUM contol chat. Based on the esults obtained fom the investigations caied out on Pacoima Dam, The system shows high pecision fo detecting defomation of a eal continuous monitoing GPS poject. A methodology fo GPS Engineeing Monitoing using GPS (GPSEM has been developed and implemented Conclusions (3 /3 Thee is a stong coelation ( 98% between the defomation that occued along the pinciple defomation axis computed fom GPSEM and changes in the wate level in the esevoi. The dam s defomations computed fom GPSEM in eal time ae consistent with those computed fom commecial softwae (i.e. SKI-Po using 4-hou solutions. The RMS of the diffeences between the two solutions in the diection of defomation is ± 0.43 mm. Recommendations and Suggestions fo Futhe Wok The system and softwae ae needed to be tested unde opeation cicumstance on eal engineeing object ( like high dam on Aswan. Moe investigations ae needed to study the behaviou of the technique unde high amplitude and fequency defomation that may occu in long-span bidges fo example.

7 THANK YOU

Figure Geometry for Computing the Antenna Parameters.

Figure Geometry for Computing the Antenna Parameters. Spheical Coodinate Systems Definitions Figue 1.2.1 Geomety fo Computing the Antenna Paametes. Antenna Radiation Patten: The distibution of adiated enegy fom an antenna ove a suface of constant adius centeed