Note that the leading edge detector is only performed if
- the AWAC firmware is version 3.31 or later (March 2010)
- the ice mode is enabled.
The ice feature in firmware is available for AWACs delivered after the end of 2008 (Midlife firmware). This is indicated by a firmware version 3.xx and a hardware serial number above 1000.
The option for a temperature compensated pressure sensor is available for AWACs after spring 2011. This is an option that does not come standard with the AWAC. The error for the pressure estimate is reduced from 0.5% to 0.1% (full scale). For a 100 meter sensor this translates to a reduction in uncertainty of 50 cm to 10 cm, which can be important when estimating ice thickness.
A discussion on estimating ice thickness can be found in two relevant papers on Nortek Insight, called "Measurements of ice parameters in the Beaufort Sea using the Nortek AWAC acoustic Doppler current profiler" and "Waves in the summer, ice in the winter".