Coordinate conversion system for strap down inertial guidance systems

Claim 1

A SYSTEM FOR CONVERTING THE COORDINATES OF A VELOCITY VECTOR REFERENCED TO A FIRST SET OF AXES IN A FIRST THREEDIMENSIONAL COORDINATE SYSTEM TO CORRESPONDING COORDINATES REFERENCED TO A SECOND SET OF AXES IN A SECOND THREE-DIMENSIONAL COORDINATE SYSTEM, SAID CONVERTING SYSTEM INCLUDING: FIRST DIGITAL SENSOR MEANS FOR SENSING LINEAR CHANGES OF THE COORDINATES OF SAID VELOCITY VECTOR WITH RESPECT TO THE FIRST COORDINATE SYSTEM AND FOR PRODUCING DIGITAL SIGNALS REPRESENTATIVE OF SUCH CHANGES; SECOND DIGITAL SENSOR MEANS FOR SENSING ANGULAR CHANGES BETWEEN THE AXES OF THE FIRST COORDINATE SYSTEM AND CORRESPONDING ONES OF THE AXES OF THE SECOND COORDINATE SYSTEM AND FOR PRODUCING DITITAL SIGNALS REPRESENTATIVE THEREOF; FIRST MULTI-DIGIT BINARY INCREMENTAL COMPUTER MEANS COUPLED TO SAID SECOND SENSOR MEANS AND RESPONSIVE TO THE DIGITAL SIGNALS THEREFROM FOR PRODUCING FIRST SIGNALS REPRESENTATIVE OF INCREMENTAL CHANGES IN THE COSINES OF THE ANGULAR DISPLACEMENTS OF THE AXES OF THE FIRST COORDINATE SYSTEM WITH RESPECT TO EACH OF THE AXES OF THE SECOND COORDINATE SYSTEM, AND FOR PRODUCING SECOND SIGNALS FOR COMPENSATING ERRONEOUS GROWTHS IN SAID FIRST SIGNALS; SAID FIRST INCREMENTAL COMPUTER MEANS INCLUDING A PLURALITY OF SECTIONS, EACH INCLUDING A REMAINDER REGISTER FOR ACCUMULATING THE LEAST SIGNIFICANT DIGITS OF A CORRESPONDING ONE OF SAID FIRST SIGNALS, AN ADDEND REGISTER FOR ACCUMULATING THE MOST SIGNIFICANT DIGITS OF THE CORRESPONDING ONE OF SAID FIRST SIGNALS, A CIRCULATING SYSTEM FOR SAID REMAINDER REGISTER INCLUDING MEANS FOR INTRODUCING OVERFLOW SIGNAL FROM SAID REMAINDER REGISTER TO SAID ADDEND REGISTER, SAID CIRCULATING SYSTEM FURTHER INCLUDING AN ADD-SUBTRACT NETWORK AND AN INPUT LOGIC NETWORK COUPLED THERETO, AND MEANS FOR INTRODUCING A CORRECTION SIGNAL DERIVED FROM A CORRESPONDING ONE OF SAID SECOND SIGNALS INTO SAID INPUT LOGIC NETWORK TO CORRECT A TENDENCY FOR THE SIGNALS ACCUMULATED IN SAID REMAINDER REGISTER TO GROW ERRONEOUSLY FOR SUCCESSIVE COMPUTE CYCLES OF SAID FIRST INCREMENTAL COMPUTER MEANS, AND SECOND INCREMENTAL COMPUTER MEANS COUPLED TO SAID FIRST DIGITAL SENSOR MEANS AND TO SAID FIRST INCREMENTAL COMPUTER MEANS AND RESPONSIVE TO SIGNALS THEREFROM PRODUCING OUTPUT SIGNALS REPRESENTATIVE OF CHANGES IN THE COORDINATES OF THE VELOCITY VECTOR WITH RESPECT TO THE AXES OF SAID SECOND COORDINATE SYSTEM.