Geodesy Research at Newcastle UniversityGeodesy Research at Newcastle UniversityPeter ClarkeProfessor of Geophysical GeodesySchool of Civil Engineering and GeosciencesNewcastle UniversityUnited Kingdom

Academic Staff

Prof. Phil MooreSpace Geodesy

Orbit modelling, gravity,

altimetry, SLR

Prof. Philippa BerryAltimetric Engineering

Inland and coastal

altimetry

Dr Stuart EdwardsEngineering / industrial

GNSS, geohazards

Prof. Peter ClarkeGeophysical Geodesy

Reference frames, GIA,

loading, tectonics, GNSS

Prof. Matt KingPolar Geodesy

Cryospheric applications

of GNSS, GIA, sea level

Dr Nigel PennaGNSS, tropospheric

water vapour, loading

Research Staff

Sophie BassettGIA, loading, andreference frames

Rossen GrebenitcharskyGravimetric geodesy and satellite orbits

Robert BalmbraAltimetry

Julien GazeauxGPS time series analysis

Ian MartinGNSS PrecisePoint Positioning

Kirill PalamartchoukGeophysical andionospheric GNSSapplications

Liz PetrieOrbital & ionospheric errors in GNSS

Impact of future satellite systems onGNSS Precise Point Positioning

• Russia’s GPS counterpart, GLONASS, being heavily developed

• Shown on a static IGS site (JPLV) as an example

• Improved convergence time with GLONASS

• GLONASS improves the RMS position error due to improved geometry

• Particularly useful for kinematic positioning and precise navigation

GPS only GPS + GLONASS

Multipath and long GPS time series

• Looking at effects of unmodelled time-constant carrier phase multipath on long GPS time series through simulation

• Simulation considers precise point positioning approach• Uses real GPS orbits, which do vary with time• Proposed mitigation approach (black) works well

King, M. A., and C. S. Watson (2010), Long GPS coordinate time series: Multipath and geometry effects, J. Geophys. Res., 115, B04403

3. Simulated effect after mitigation

1. Real height series

Effects of unmodelled multipath on height at site in Antarctica (MCM4)

2. Simulated multipath effect (blue/magenta)

Sidereal filtering to improve small-scale deformation monitoring

• Removing multipath-related coordinate errors• Using single-epoch GASP

software (in-house)• GPS sidereal period of 86154 s• Switched

antennafor localnetwork

Ragheb et al., Proc. ION NTM, 2007; Ragheb et al., J. Geodesy, 2007; Ragheb et al., J. Surv. Engrg., 2010

Ocean tide loading and Earth structure

Allinson et al., GRL, 2004; King et al., JGR, 2005; Thomas et al., J. Geodesy, 2007; Clarke & Penna, Surv. Rev., 2010;

Inter-model stdev, 10x scale

• Significant anomaliesat M2 period in W Europe• Not explained by differences

between, or errors in, oceantide models

• May be due to change in upper mantle elasticityat tidal periods

• No other geophysicalsignal probes this frequency

FES2004+PREM modelled M2 OTL

M2 residuals to GPS observations (FES2004 model)

Non-tidal ocean loading effects on geodetic GPS heights

• Non-tidal (e.g. surge) ocean loading not considered in GPS analysis• Modelled land displacement according to the global ECCO model and

the regional high resolution POLSSM model• Correlation of >0.7 with state-of-the-art GPS height time series• Reduces variance up to 30-40%, POLSSM slightly outperforming ECCO• Global high resolution non-tidal ocean models needed for geophysical

GPS work

TERS

Williams & Penna (2011), Geophys. Res. Lett.

Precise orbit determination and satellite laser ranging

In house software: Faust

Lavallée, D. A., P. Moore, P. J. Clarke, E. J. Petrie, T. van Dam, and M. A. King (2010), J2: An evaluation of new estimates from GPS, GRACE, and load models compared to SLR, Geophys. Res. Lett., 37, L22403, doi:10.1029/2010GL045229.

Luang Prabang

Vientiane

Nakhon P hanom

Kratie

ENVI(20.0n101.9e) - Day 3

ERS2(17.8n102.6e) - Day 20ENVI(17.8n102.6e) - Day 20

ERS2(17.5n104.7e) - Day 16ENVI(175.n104.7e) - Day 16

ERS2(17.5n104.6e) - Day 33

ERS2(12.2n105.9e) - Day 16ENVI(12.2n105.9e) - Day 16

Measured Stage data - Mekong

Measured Stage data - Tributaries

Satellite data - ENVISAT (2002-2008)

Satellite data - ERS-2 (1995-2003)

Tonle Sap Lake

Longitude (º E)

Lat

itu

de

(º N

)

Kom pong Cham

ERS2(11.9n105.2e) - Day 35ENVI(11.9n105.2e) - Day 4

Stung Treng

PaksaneERS2(18.3n103.8e) - Day35

ERS2/ENVISAT altimetry data on Mekong. Satellite altimetry as virtual gauge data every 35 days

-6

-4

-2

0

2

4

6

8

10

12

-600 -400 -200 0 200 400 600Ch

anne

l Sta

ge (m

)Channel width (m)

Measured

Estimated depth

Shallow bound

Deep bound

Nakhon phanom

Vientiane

Channel cross-sections from Landsat and SAR and different bathymetric depths for the 50km reach at Nakhon Phanom and Vientiane.

Use of remote sensing data for discharge in ungauged catchments

y = 132.81x2 + 639.65x + 1122.6R² = 0.9994

0

5000

10000

15000

20000

25000

30000

35000

40000

-2 0 2 4 6 8 10 12 14

Dis

char

ge (m

3 /s)

Channel stage(m)

MeasuredMeasured upper/lower boundEstimatedEstimated upper/lower bound

a)

Measured and estimated stage-discharge relationships from 1996-2005 at Nakhon Phanom

Q = 7.22 W1.02 Y1.74 S0.35

Q discharge; W river width, Y waterdepth (m), S channel slope.Bjerklie et al. (2003)

International GNSS Service

• Weekly combinationof GPS reference frame• In-house TANYA s/ware• Backup/check to official

IGS solution

• Host of IGS 2010 Workshop

Observe mm level changes in Earth’s shape with global network of GPS receivers

Blewitt et al., Science, 2001; Blewitt & Clarke, JGR, 2003; Gross et al., GRL, 2004; Clarke et al., GRL, 2005; Lavallée et al., JGR, 2006; Clarke et al., GJI, 2007; Lavallée et al., GRL, 2010

Invert shape for mass distribution using an elastic Earth model, like the spring in a set of scales

SecularMotion =

TectonicMotion

Postglacial rebound+ +

Loading deformation

Surface mass loading deformation & the hydrological cycle

uplift rate (mm/yr)

Antarctic GIA (models vs GPS)

West Antarctica

East Antarctica

Thomas et al. (2011), Geophys. Res. Lett., 38, L22302

GPS deployments 2013-14

• Mt Wollard & Martin Hills (solar+wind)

• Mt Johns solar only occupying existing site with historic data

Lower estimates of Antarctic sea level contribution from satellite gravimetryKing, Bingham, Moore, Whitehouse, Bentley and Milne (2012) Nature, 491, 586-589.

Estimates of basin- scale Antarctic ice mass change from GRACE for Aug 2002 – Dec 2010 in Gt/yr. Best, lower and upper values.

Continent-wide ice mass change of -69±18 Gt yr-1 (+0.19±0.05 mm yr-1 sea-level equivalent).

GNSS / geodesy consultancy and CPD

• Network RTK benchmarking

• CPD courses:• GNSS and Network RTK

• High Precision GNSS using Post-processing

• Least Squares Adjustment for Offshore Survey

• Precise GNSS Positioning• deformation monitoring