A method to assure integrity of integrated certified and non-certified sensors or systems that provide measurements, the method comprising: calculating a certified main solution filter operative to process a set of certified measurements within a first software thread in a certified partition; calculating one or more certified sub-solution filters operative to process all but one measurement from the set of certified measurements, and sub-sub-solution filters operative to process all but two measurements from the set of certified measurements within the first software thread in the certified partition; calculating a non-certified main solution filter operative to process a set of non-certified measurements and the set of certified measurements within a second software thread in a non-certified partition; depending on the number of non-certified measurements, reusing the certified main solution filter as a non-certified sub-solution filter operative to process all but one measurement from the sets of non-certified and certified measurements, and reusing the certified sub-solution filters, as non-certified sub-sub- solution filters operative to process all but two measurements from the sets of non-certified and certified measurements; calculating one or more non-certified sub-solution filters, and sub-sub-solution filters, within the second software thread in the non-certified partition; based on the certified filters, determining one or more protection limits of the certified partition, and/or providing execution of fault detection and exclusion; based on the non-certified filters, determining one or more protection limits of the non-certified partition, and/or providing execution of fault detection and exclusion; outputting one or more certified solutions from the certified partition; and outputting one or more non-certified solutions from the non-certified partition. calculating a certified main solution filter operative to process a set of certified measurements within a first software thread in a certified partition; calculating one or more certified sub-solution filters operative to process all but one measurement from the set of certified measurements, and sub-sub-solution filters operative to process all but two measurements from the set of certified measurements within the first software thread in the certified partition; calculating a non-certified main solution filter operative to process a set of non-certified measurements and the set of certified measurements within a second software thread in a non-certified partition; depending on the number of non-certified measurements, reusing the certified main solution filter as a non-certified sub-solution filter operative to process all but one measurement from the sets of non-certified and certified measurements, and reusing the certified sub-solution filters, as non-certified sub-sub- solution filters operative to process all but two measurements from the sets of non-certified and certified measurements; calculating one or more non-certified sub-solution filters, and sub-sub-solution filters, within the second software thread in the non-certified partition; based on the certified filters, determining one or more protection limits of the certified partition, and/or providing execution of fault detection and exclusion; based on the non-certified filters, determining one or more protection limits of the non-certified partition, and/or providing execution of fault detection and exclusion; outputting one or more certified solutions from the certified partition; and outputting one or more non-certified solutions from the non-certified partition. <EOS>