Method of determining position and/or direction of a magnetic target

A method for determining position and/or direction of a target, the target having a series of magnetic poles with a magnetic pole spacing d, the method comprising:

• providing an array of an even number N of magnetic sensors with a sensor spacing x, the sensor array having an initial effective sensor array length (N+1)x, where the initial effective sensor array length is greater than twice the pole spacing d;
• deactivating an equal number of magnetic sensors such that the magnetic sensors of the array remaining active are adjacent to each other and provide a new effective sensor array length that is closer to the pole spacing d than the initial effective sensor array length;
• dividing the magnetic sensors of the array remaining active into four equal groups A, B, C and D of at least one adjacent magnetic sensor for signal processing;
• summing the signals from each of the four groups of magnetic sensors;
• subtracting the summation of signals from groups A and D from the summation of signals from groups B and C to obtain a sine wave;
• and
• subtracting the summation of signals from groups C and D from the summation of signals from groups A and B to obtain a cosine wave.

A method for determining position and/or direction of a target, the target having a series of magnetic poles with a magnetic pole spacing d, the method comprising:

• providing an array of an even number N of magnetic sensors with a sensor spacing x, the sensor array having an initial effective sensor array length (N+1)x, where the initial effective sensor array length is greater than twice the pole spacing d;
• deactivating an equal number of magnetic sensors such that the remaining magnetic sensors are adjacent to each other and provide a new effective sensor array length that is closer to the pole spacing d than the initial effective sensor array length;
• dividing the remaining magnetic sensors of the array into two equal groups A and B of adjacent magnetic sensors for signal processing;
• summing the signals from group A and summing the signals from group B;
• adding the summation of signals from group B to the summation of signals from group A to obtain a sine wave;
• subtracting the summation of signals from group B from the summation of signals from group A to obtain a cosine wave;
• and
• using a scaling means to balance the amplitude of the sine wave with respect to the amplitude of the cosine wave.

A method for determining position and/or direction of a target, the target having a series of magnetic poles with a magnetic pole spacing d, the method comprising:

• providing an array of an even number N of magnetic sensors with a sensor spacing x, the sensor array having an initial effective sensor array length (N+1)x, where the initial effective sensor array length is greater than twice the pole spacing d;
• deactivating an equal number of magnetic sensors such that the remaining active magnetic sensors are adjacent to each other and provide a new effective sensor array length that is closer to the pole spacing d than the initial effective sensor array length;
• dividing the remaining magnetic sensors of the array into four equal groups A, B, C and D of adjacent magnetic sensors for signal processing;
• summing the signals from each of the four groups of magnetic sensors;
• subtracting the summation of signals from groups A and D from the summation of signals from groups B and C to obtain a sine wave;
• and
• subtracting the summation of signals from groups C and D from the summation of signals from groups A and B to obtain a cosine wave;
• and
• using a scaling means to balance the amplitude of the sine wave with respect to the amplitude of the cosine wave.

An ASIC (application specific integrated circuit) chip for determining position and/or direction of a target having magnetic poles, the ASIC chip comprising:

• an array comprising an even number of magnetic sensors providing an effective array length;
• selection means to selectively deactivate at least one even number of magnetic sensors such that the magnetic sensors of the array remaining active are adjacent to each other;
• and
• signal processing means to process signals from the remaining magnetic sensors to generate a sine wave and a cosine wave.