Method of altitude track initialization in an aircraft tracking system
First Claim
1. A method of processing a plurality of replies of target aircraft provided in response to interrogation signals from a surveillance aircraft during surveillance periods to determine whether an altitude track may be initialized for use in a traffic alert and collision avoidance system, said method comprising the steps of:
- selecting three replies, one from each of three consecutive surveillance periods, said replies having binary or coded altitude data of high or low confidence;
comparing the binary or coded altitude data of non-adjacent and adjacent replies of the selected replies and generating an altitude difference value for each of the comparisons;
discarding further efforts to initialize a track if any of the altitude difference values are greater than first predetermined separated altitudes if and only if such non-adjacent and adjacent replies have binary or coded altitude data of high confidence; and
further comparing the binary or coded altitude data of the non-adjacent and the adjacent replies whether or not the replies have binary data of low or high confidence to determine whether an altitude track may be initialized.
3 Assignments
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Accused Products
Abstract
A method of processing a plurality of replies of target aircraft provided in response to interrogation signals from the surveillance aircraft during surveillance periods to determine whether an altitude track may be initialized for use in a traffic alert and collision avoidance system includes the step of selecting three replies, one from each of three consecutive surveillance periods. The replies have binary or coded altitude data of high or low confidence. The binary or coded altitude data of non-adjacent and adjacent replies of the selected replies are compared and an altitude difference value for each of the comparisons is generated. Further efforts to initialize a track are discarded if any of the altitude difference values are greater than first predetermined separated altitudes if and only if such compared non-adjacent and adjacent replies have binary or coded altitude data of high confidence. The binary or coded altitude data of the non-adjacent and adjacent replies are further compared whether or not the replies have binary data of low or high confidence to determine whether an altitude track may be initialized. The process applies if the altitude data is Gilham code, binary, or other encoded data with single bit errors.
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Citations
7 Claims
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1. A method of processing a plurality of replies of target aircraft provided in response to interrogation signals from a surveillance aircraft during surveillance periods to determine whether an altitude track may be initialized for use in a traffic alert and collision avoidance system, said method comprising the steps of:
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selecting three replies, one from each of three consecutive surveillance periods, said replies having binary or coded altitude data of high or low confidence; comparing the binary or coded altitude data of non-adjacent and adjacent replies of the selected replies and generating an altitude difference value for each of the comparisons; discarding further efforts to initialize a track if any of the altitude difference values are greater than first predetermined separated altitudes if and only if such non-adjacent and adjacent replies have binary or coded altitude data of high confidence; and further comparing the binary or coded altitude data of the non-adjacent and the adjacent replies whether or not the replies have binary data of low or high confidence to determine whether an altitude track may be initialized. - View Dependent Claims (2, 3, 4)
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5. A method of processing a plurality of replies of target aircraft provided in response to interrogation signals from a surveillance aircraft during surveillance periods to determine whether an altitude track may be initialized for use in a traffic alert and collision avoidance system, said method comprising the steps of:
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selecting a reply having binary or coded altitude data of high or low confidence from three consecutive surveillance periods; comparing the binary or coded altitude data of each of the selected replies to the binary or coded altitude data of the other selected replies; generating altitude value differences representative of a difference in altitude of each comparison and bit difference values representative of whether a certain number of bits of the binary or coded altitude data are different for the replies of each comparison; and comparing the altitude value differences to predetermined altitude difference values and the bit difference values to a predetermined number of bits to determine depending on whether the binary or coded altitude data is of high or low confidence whether the altitude track may be initialized from the selected replies. - View Dependent Claims (6, 7)
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Specification