Ath system method and apparatus for locating movable objects on a fixed p

Claim 1

A system for indicating the position of a movable object on a fixed path, comprising: a. markers arranged along the path to define successive path sections, each marker representing the binary digit 1 or the binary digit 0 such that the set of markers define at least part of a predetermined pseudo-random binary sequence; b. a detector carried by the movable object for sensing each marker; c. register means coupled to the detector to receive the successive binary digits and store them in successive groups of m digits, the groups all being different, and each group signifying a respective position of the movable object along the path; d. error detection means for detecting errors in the m digit groups in accordance with the properties of the pseudo-random sequence, said error detection means including: sum means for providing the sum modulo (2) of at least two preselected binary digits in each m digit group; coincidence means for receiving at least one output of the detector and at least one output of the sum means; a counter means for counting successive coincidences in the coincidence means; non-coincidence indication means for resetting the counter means to a start configuration; numerical threshold detector means coupled to the counter for providing an indication that a predetermined number k of successive coincidences have been received by the counter means, k being the difference between m and the minimum number of n of binary digits with which n digit groups can be formed from the binary sequence without duplication; and e. inhibiting means for inhibiting the indication of a position in response to detection of an error in the respective m digit group by the error detection means.

Claim 2

A system for indicating the position of a movable object on a fixed path, comprising: a. markers arranged along the path to define successive path sections, each marker representing the binary digit 1 or the binary digit 0 such that the set of markers define at least part of a predetermined pseudo-random binary sequence; b. a detector carried by the movable object for sensing each marker; c. register means coupled to the detector to receive the successive binary digits and store them in successive groups of m digits, the groups all being different, and each group signifying a respective position of the movable object along the path; d. error detection means for detecting errors in the m digit groups in accordance with the properties of the pseudo-random sequence, said error detection means including: sum means for providing the sum modulo (2) of at least two preselected binary digits in each m digit group; coincidence means for receiving at least one output of the detector and at least one output of the sum means; a counter means for counting successive coincidences in the coincidence means; non-coincidence indication means for resetting the counter means to a start configuration; numerical threshold detector means coupled to the counter for providing an indication that a predetermined number k of successive coincidences have been received by the counter means, k being the difference between m and the minimum number of n of binary digits with which n digit groups can be formed from the binary sequence without duplication; and e. inhibiting means for inhibiting the indication of a position in response to detection of an error in the respective m digit group by the error detection means.

Claim 6

A method for indicating the position of a movable object on a fixed path comprising the steps of: a. arranging markers along the path to define successive path sections, each marker representing the binary digit 1 or the binary digit 0 and the set of markers defining at least part of a predetermined psuedo-random binary sequence; b. detecting the binary digit associated with each marker; transferring the successive binary digits to a register in which they are stored in successive groups of m digits each group being different and signifying a respective position of the movable object; c. detecting errors in the m digit groups in accordance with the properties of the pseudo-random sequence, wherein errors in the m digit groups are detected by: providing the sum modulo (2) of at least two preselected binary digits in each m digit group; counting successive coincidences between the sum modulo (2) and the detection of a marker; indicating a non-coincidence between the sum and the detection of a marker; restarting the count on each non-coincidence; providing an enabling indication when a predetermined number k of successive coincidences has been obtained, k being the difference between m and the minimum number n of binary digits with which n digit groups can be formed from the binary sequence without duplication; and d. inhibiting an indication of a position in response to detection of an error in the respective m digit group.

Claim 7

A method for indicating the position of a movable object on a fixed path comprising the steps of: a. arranging markers along the path to define successive path sections, each marker representing the binary digit 1 or the binary digit 0 and the set of markers defining at least part of a predetermined psuedo-random binary sequence; b. detecting the binary digit associated with each marker; transferring the successive binary digits to a register in which they are stored in successive groups of m digits each group being different and signifying a respective position of the movable object; c. detecting errors in the m digit groups in accordance with the properties of the pseudo-random sequence, wherein errors in the m digit groups are detected by: providing the sum modulo (2) of at least two preselected binary digits in each m digit group; counting successive coincidences between the sum modulo (2) and the detection of a marker; indicating a non-coincidence between the sum and the detection of a marker; restarting the count on each non-coincidence; providing an enabling indication when a predetermined number k of successive coincidences has been obtained, k being the difference between m and the minimum number n of binary digits with which n digit groups can be formed from the binary sequence without duplication; and d. inhibiting an indication of a position in response to detection of an error in the respective m digit group.

Claim 14

A system for locating a movable object on a given path, comprising: a. means arranged along the path and dividing it into N stages, said means representing the binary digits 0 and 1, the sequence of said binary digits along the path defining at least part of a pseudo-random sequence of maximal length; b. detection means on said movable object for successively detecting each of said binary digits of said sequence; c. recording means coupled to said detection means for recording the successive detected binary digits in words of m binary digits, m being so chosen that all the words recorded are different, each of said words being representative of a position of the movable object on the path; d. analyzing means coupled to said detection means and said recording means for analyzing the accuracy of a recorded word, said analyzing means comprising: coincidence means having a first input connected to said detector means and a second input connected to a sum means for effecting the sum modulo (2) of at least two binary digits present in said recording means; counting means connected to said coincidence means to count the number of successive coincidences; non-coincidence means for resetting said counting means to zero upon occurrence of a non-coincidence between said sum means and said detector means; a numerical threshold detector means connected to the counter means for providing a signal when the count in the counter is at least equal to k wherE k is the difference between m and the minimum number of binary digits in each different word; and e. inhibiting means for inhibiting the read out of a recorded word when it is inaccurate.

Claim 15

A system for locating a movable object on a given path, comprising: a. means arranged along the path and dividing it into N stages, said means representing the binary digits 0 and 1, the sequence of said binary digits along the path defining at least part of a pseudo-random sequence of maximal length; b. detection means on said movable object for successively detecting each of said binary digits of said sequence; c. recording means coupled to said detection means for recording the successive detected binary digits in words of m binary digits, m being so chosen that all the words recorded are different, each of said words being representative of a position of the movable object on the path; d. analyzing means coupled to said detection means and said recording means for analyzing the accuracy of a recorded word, said analyzing means comprising: coincidence means having a first input connected to said detector means and a second input connected to a sum means for effecting the sum modulo (2) of at least two binary digits present in said recording means; counting means connected to said coincidence means to count the number of successive coincidences; non-coincidence means for resetting said counting means to zero upon occurrence of a non-coincidence between said sum means and said detector means; a numerical threshold detector means connected to the counter means for providing a signal when the count in the counter is at least equal to k wherE k is the difference between m and the minimum number of binary digits in each different word; and e. inhibiting means for inhibiting the read out of a recorded word when it is inaccurate.