International patent application PCT/FI96/00621 has already become a basis of many regional and national patents:

"Method for adaptive K-Filtering in dynamic systems"
Inventor: Lange, Antti A. I.

Abstract

This invention was based on the use of the principles of Lange's Fast K-Filtering (FKF) for large process control, prediction or warning systems where other computing methods are either too slow or fail because of truncation errors due to restricted mantissa lengths (such as high-precision GNSS navigation). The invented method is still making it possible to exploit the FKF method for safety-critical dynamic multiparameter systems with slow-varying calibration parameters using sufficiently large moving data-windows (such as various environmental controls like weather prediction).

This invention belonged to the patent family of 50 patents from two previous international applications PCT/FI90/00122 and PCT/FI93/00192. It extended the FKF patent coverage almost up to 100 countries. The International Preliminary Examination (IPE) was successfully accomplished by the European Patent Office (EPO) on December 29, 1997, and EPO granted the European patent accordingly.

These patents were in force until expiration (until 2017) in some of the following countries:
Albania, Armenia, Austria, Australia, Azerbaijan, Barbados, Belgium, Belarus, Benin, Bosnia, Bulgaria, Burkina Faso, Brazil, Cameroon, Canada, Central African Republic, Chad, China, Congo, Czech Republic, Denmark, Estonia, Finland, France, Gabon, Georgia, Germany, Guinea, Greece, Hungary, Israel, Iceland, Ireland, Italy, Ivory Coast, Japan, Kazakstan, Kenya, Korea, Korea, People's Republic of, Kyrgyzstan, Latvia, Lesotho, Liechtenstein, Lithuania, Luxemburg, Madagascar, Malawi, Mali, Mauritania, Mexico, Moldova, Monaco, Mongolia, Netherlands, New Zealand, Niger, Norway, Poland, Portugal, Romania, Russian Federation, Senegal, Singapore, Slovenia, Slovakia, Spain, Sudan, Swaziland, Sweden, Switzerland, Tajikistan, Togo, Turkey, Turkmenistan, Uganda, Ukraine, United Kingdom, United States of America, Uzbekistan, Vietnam.
* Last revised: Jan. 21, 2018