Space Geodesy Programme

The GPS Tide Gauge Benchmark Monitoring - Pilot Project (TIGA-PP)  is a pilot study of the International GPS Service (IGS). The main objective of TIGA is establishing a service to analyse GPS data from stations at or near tide gauges on a continuous basis.  The primary product of the service is time series of coordinates of tide gauges and associated benchmarks. This product will allow distinction between absolute and relative sea level changes by accounting for the vertical movement of the station.  TIGAsA is a collaborative project between HartRAO, NASA(JPL), the SA NAVY (Hydrographic Office) and several other partners.  Within TIGA, TIGAsA will function as a TIGA Associate Analysis Centre (TAAC), TIGA Data Centre (TDC) and will install and maintain TIGA Observing Stations (TOS).

The Tide Gauge (gold-coloured tube at end of boom) with the communications equipment, located at Marion Island.

Introduction

TIGAsA was initiated by the Hartebeesthoek Radio Astronomy Observatory (HartRAO) in response to the "Call for Participation" letter from the IGS, which solicited participation by agencies in the functions and objectives of TIGA. HartRAO was already in the process of installing GPS equipment at tide gauges and saw TIGA as an essential project to address the problem of analysing vertical motions at tide gauges on a global scale.

A meeting was subsequently organised and held (27 July 2001) at Environmentek (CSIR), Stellenbosch with possible participants. This meeting culminated in TIGAsA, the southern Africa component of TIGA.
 

Objectives

The objectives of TIGAsA have been identified within the framework of the objectives of TIGA, but have a regional approach

1. Establish, maintain and expand a regional continuous GPS @ Tide Gauge network,  which will form part of the TIGA global CGPS @ TG network.
2. Function as a TIGA Associate Analysis Centre (TAAC)

3. Function as a TIGA Data Centre

The following are TIGA stations mainained by HartRAO:

• Simonstown (SIMO)

• Richardsbay (RBAY)

• Marion Island (MARN)