Method and apparatus for associating target replies with target signatures

Apparatus for associating target reply signals with target signatures, wherein each reply signal is received from a target transponder within a selectable time period, and further wherein each target signature comprises a first set of parameter values that identify a target position and movement relative to an interrogating aircraft, comprising:

• antenna means for receiving the reply signals and producing phase related signals corresponding to target bearing and video signals corresponding to range based on a differential time of arrival (DTA) value relative to said time period;
• means for determining an altitude code associated with each reply signal;
• and
• processing means for:
• 1) producing, for each reply signal, a target report comprising a second set of parameters that includes at least a DTA value and may include altitude and bearing data when available from the reply signal;
• 2) comparing each target report with each of the target signatures to identify which report/signature pairs are potential matches, each comparison between a target report and a target signature being based on comparisons of corresponding parameter values to provide a probability of match for each parameter comparison;
• and 3) determining which target reports best match respective target signatures based on a comparison of each report/signature potential match with each other potential report/signature potential match including comparison of said parameters' probabilities of match.

A method for associating target reply signals with target signatures, wherein each reply signal is received from a target transponder within a selectable time period, and further wherein each target signature comprises a first set of parameter values that identify a target position and movement relative to an interrogating aircraft, comprising the steps of:

• a. producing a target report for each reply signal, said target report comprising a second set of parameter values;
• b. comparing each target report with each target signature to identify which report/signature pairs are potential matches, each comparison between a target report and a target signature being based on comparisons of corresponding parameter values to produce a probability of match for each parameter comparison;
• and
• c. identifying ambiguous report/signature matches based on comparison of each report/signature potential match with each other potential report/signature potential match and a best report/signature match from said identified ambiguous matches based on a comparison of said parameters' probabilities of match thereof.

Apparatus for associating target reply signals with target signatures, wherein each reply signal is received from a target transponder within a selectable time period, and further wherein each target signature comprises a first set of parameter values that identify a target position and movement relative to an interrogating aircraft, comprising:

• reply processor means for producing a target report for each reply signal, said target report comprising a second set of parameter values;
• and
• report processing means for:
• 1) comparing each target report with each target signature to identify which report/signature pairs are potential matches, each comparison between a target report and a target signature being based on comparisons of corresponding parameter values to produce corresponding probability of match for each parameter comparison;
• and 2) identifying ambiguous report/signature matches based on comparison of each report/signature potential match with each other potential report/signature potential match and a best report/signature match from said identified ambiguous matches based on a comparison of said parameters' probabilities of match thereof.

A method for improving target track initiation comprising the steps of:

• a. using a directional antenna to detect reply signals transmitted from a target during discrete time periods;
• b. determining a target bearing value for each of said detected reply signals;
• c. computing a bearing velocity (v.sub..theta.) based on bearing rate of change during said time periods;
• and
• d. attenuating said bearing velocity in relation to range of the target.