Electronic file and record keeper for secondary radar targets

Claim 1

A method for maintaining IFF target position information and for providing target status information regarding new target position information ρ new , θ new and previously stored position information ρ i , θ i received in a scanning antenna system, and for providing a target status indication comprising the steps: comparing ρ new , θ new with each ρ i , θ i previously stored, forming a difference quantity Δρ=|ρ new - ρ i |; forming a difference quantity Δθ = |θ new - θ i |; storing ρ new , θ new as a new target if the difference quantity Δρ or the difference quantity Δθ, is greater than corresponding predetermined quantities Δρ o , Δθ o and the new information is accompanied by a 4U unknown target input signal; replacing corresponding position information with updated position information ρ new , θ new if said new position information is accompanied by a 4U unknown target input signal and either of said differences Δρ, Δθ are less than said corresponding quantities Δρ o , Δθ o ; removing corresponding position information ρ i θ i if said differences Δρ, Δθ are less than said corresponding quantities Δρ o , Δθ o and said new position information is accompanied by a friend accept input signal; counting the number of antenna scans; removing a target position from storage when said counted number of antenna scans exceeds a predetermined number; counting the number of chances the target is given to properly respond to interrogations; declaring a target unknown when said count of chances the target is given to properly respond is greater than a predetermined number.

Claim 2

A method for maintaining IFF target position information and for providing target status information regarding new target position information ρ new , θ new and previously stored position information ρ i , θ i received in a scanning antenna system, and for providing a target status indication comprising the steps: comparing ρ new , θ new with each ρ i , θ i previously stored, forming a difference quantity Δρ=|ρ new - ρ i |; forming a difference quantity Δθ = |θ new - θ i |; storing ρ new , θ new as a new target if the difference quantity Δρ or the difference quantity Δθ, is greater than corresponding predetermined quantities Δρ o , Δθ o and the new information is accompanied by a 4U unknown target input signal; replacing corresponding position information with updated position information ρ new , θ new if said new position information is accompanied by a 4U unknown target input signal and either of said differences Δρ, Δθ are less than said corresponding quantities Δρ o , Δθ o ; removing corresponding position information ρ i θ i if said differences Δρ, Δθ are less than said corresponding quantities Δρ o , Δθ o and said new position information is accompanied by a friend accept input signal; counting the number of antenna scans; removing a target position from storage when said counted number of antenna scans exceeds a predetermined number; counting the number of chances the target is given to properly respond to interrogations; declaring a target unknown when said count of chances the target is given to properly respond is greater than a predetermined number.

Claim 3

A device for maintaining IFF target position information and for providing target status information regarding new position ρnew, θ new information and previously stored position ρ i , θ i information and providing a target status indication comprising: means for receiving said position information ρ new, θnew, friend-accept and 4U unknown input signals; means coupled to said receiving means for storing a plurality of pairs ρ i , θ i of received position information; means coupled to said receiving means and to said storage means for comparing a new position pair ρ new, θ new with each previously stored pair ρ i , θ i ; means coupled to said comparing means and to said storage means for storing said new position pair ρ new, θ new if ρnew differs from each stored ρ i by more than a predetermined quantity Δρ o , or if θ new differs from each stored θ i by more than a predetermined quantity Δθ o and said new position information is accompanied by a said 4U unknown input signal, and for replacing a corresponding position pair with said new position pair ρ new, θ new if ρ new differs from each stored ρ i by less than said predetermined quantity Δρ, or if θ new differs from each stored θ i by less than said predetermined quantity Δθ o , and said new position information is accompanied by a said 4U unknown input signal; means coupled to said storage means and to said comparing means for counting the number of antenna revolutions past the target corresponding to each position pair; means coupled to said antenna counting means and to storage means for removing a position pair from storage when said antenna revolution count exceeds a predetermined number for the corresponding position pair; means coupled to said storage means and to said comparing means for counting the number of chances each position pair ρ i θ i target has been given to properly respond; means coupled to said chances given counting means and to said storage means for indicating that a corresponding target is an unknown when said chances-given count exceeds a predetermined number for the corresponding position pair.

Claim 4

A device for maintaining IFF target position information and for providing target status information regarding new position ρnew, θ new information and previously stored position ρ i , θ i information and providing a target status indication comprising: means for receiving said position information ρ new, θnew, friend-accept and 4U unknown input signals; means coupled to said receiving means for storing a plurality of pairs ρ i , θ i of received position information; means coupled to said receiving means and to said storage means for comparing a new position pair ρ new, θ new with each previously stored pair ρ i , θ i ; means coupled to said comparing means and to said storage means for storing said new position pair ρ new, θ new if ρnew differs from each stored ρ i by more than a predetermined quantity Δρ o , or if θ new differs from each stored θ i by more than a predetermined quantity Δθ o and said new position information is accompanied by a said 4U unknown input signal, and for replacing a corresponding position pair with said new position pair ρ new, θ new if ρ new differs from each stored ρ i by less than said predetermined quantity Δρ, or if θ new differs from each stored θ i by less than said predetermined quantity Δθ o , and said new position information is accompanied by a said 4U unknown input signal; means coupled to said storage means and to said comparing means for counting the number of antenna revolutions past the target corresponding to each position pair; means coupled to said antenna counting means and to storage means for removing a position pair from storage when said antenna revolution count exceeds a predetermined number for the corresponding position pair; means coupled to said storage means and to said comparing means for counting the number of chances each position pair ρ i θ i target has been given to properly respond; means coupled to said chances given counting means and to said storage means for indicating that a corresponding target is an unknown when said chances-given count exceeds a predetermined number for the corresponding position pair.