Backer Island GNSS system (IMAGE) McGill University Caption The field team used specialized instruments from the ANET-POLENET project that measure Antarctica’s ground motion. This GNSS [GPS] station is located on an island of the Backer Islands chain in Pine Island Bay where the massive Pine Island Glacier enters the Amundsen Sea. Credit Terry Wilson Usage Restrictions . License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.