Bit error rate estimates are used for measuring link quality in a radio telecommunications system. In response to the decoded arithmetic returning high half instruction, the data processor specifies within the register data store one or more source registers to store a plurality of source data elements of a first size, and one or more destination registers to store a corresponding plurality of resultant data elements of a second size. A blind adaptive nulling processor is cascaded ahead of the GPS receiver so that the GPS receiver can operate on the jamming-suppressed signals in a normal manner.