There are fundamental differences between an NRL-style goniometer and the Surface Analyst, most of which contribute to the value of the measurement for development and control of surface sensitive manufacturing processes.
These include the method of liquid deposition and the method of contact angle calculation once the liquid drop is deposited.
The original motivation for these differences was to allow for a more compact and convenient instrument that could be easily handheld. However, they also significantly improve the speed and accuracy of the measurement as well as the flexibility of the types of surfaces that can be measured.
Download the Paper: The Surface Analyst™: Advanced Goniometry for Manufacturing