Several years ago I corresponded with senior Royal Dutch Shell lawyers concerning allegations made by a former employee of Shell Oil Company, Mr Frank Joseph Trunk III., about alleged Shell sponsored industrial espionage.
The ingenious Mr Trunk filed for patents in the 1990s and early 2000s that define certain novel technologies with important dual use (military and civilian) applications.
It is quite likely that in a related move Shell tried to patent the use of spread spectrum signaling for controlling a BOP in a noisy environment, based on the number of other things they tried to patent disclosed to them under confidentiality agreements. Digital spread spectrum acoustic signaling is also used in a number of naval/military applications.