Raymond and Ivins 1

Remote GPS Networks:Rationale

Carol A. Raymond, Erik R. Ivins

JPL/Caltech

Raymond and Ivins 2

Rationale for Antarctic Continuous GPS stations and Constraints on Station Architecture

Rationale for Continuous Measurements: Vertical rates are low (typically few cm?) and need for accuracy is

high to resolve gentle gradients Incomplete noise characterization (phase center drifts, biases,

seasonal tropospheric variations, ionosphere, reference frame issues)for data lengths of < 30 days?

Constraints: If rheology is stiff, and loads are ancient, uplift gradients are small If loads are young, uplift gradients might be large. Likely there will be a spectrum of uplift scales that must be

deconvolved to understand their origin in lateral heterogeneity of earth rheology, and/or glacial loading histories of individual drainage basins

Continuous GPS measurements contribute to understanding the Continuous GPS measurements contribute to understanding the interaction between ice sheet history and dynamics, and earth rheology. interaction between ice sheet history and dynamics, and earth rheology. Support time-varying gravity measurements of ice mass change. Support time-varying gravity measurements of ice mass change.

Raymond and Ivins 3

High precision vertical components are critical for distinguishing competing models

Current results favor recent ice mass change - indicating smaller scale gradients are expected

Raymond and Ivins 4

Network proposed in 2004 (Raymond et al.) is designed to measure glacioisostatic deformation in region most sensitive to testing models

Donnellan and Luyendyk (1997-2001)

Air Force Seismic Stations (new)

Raymond et al. (1996-2001)

Proposed TAM CGPS Network

continues decadal-length

times series at 4 sites

W12

W1

WAGN occupations

W13

TA

MD

EF

Raymond and Ivins 5

Proposed Next-Generation Station Architecture

Raymond and Ivins 6

• Magnetometer package is undergoing lab thermal testing (30 C to -60C)

• Stratospheric balloon tests in October 2004

• Components, software and architecture can be reused for GPS stations

Picosat and UAV System Engineering (PAUSE)

single board computer

Freewave modem

Li-SoCl2 batteries

magnetometer

Raymond and Ivins 7

Tumbleweed Polar Rover