GGG: 2nd generation prototype
Improved electronics with hardwired phase information on each data point  (ring with holes …). Accuracy of reference system transformation crucial ….
Weaker laminar (cardanic) suspensions: reduction of seismic tilt effects, better rejection of common mode effects (i.e. horizontal seismic noise), longer differential periods  Þ higher sensitivity … (need to gain factor 100)
Bi-axial tiltmeter to provide driving signal for active control of tilts with PZT: crucial to improve sensitivity and for long term measurements (testing for EP violation in the field of the Sun)