Abstract: In an embodiment, an apparatus includes a detector and a range finder. The detector is configured to determine a direction to a target in response to a signal received from the target, and the range finder is configured to determine a range to the target in response to the direction and independently of an amplitude of the signal. For example, such an apparatus (e.g., a computer-based apparatus) may be disposed on tactical fighter aircraft, and may be able to range (e.g., azimuth range or slant range) a target passively even if an accurate measure of the amplitude of the signal received from the target is unavailable.

Abstract: In an embodiment, a coordinate determiner is operable to identify at least first and second surfaces that each approximately intersect an object, and to determine at least two approximate coordinates of the object from the first and second surfaces, where at least one of the surfaces is nonplanar. For example, if the coordinate determiner is disposed on a fighter jet having at least two short-baseline-interferometers (SBIs), then two surfaces may be the surfaces of two cones having two of the SBIs as respective vertices, the object may be a close-in target, and the coordinate determiner may determine the azimuth and elevation of the target from the cone surfaces. Furthermore, the coordinate determiner or another computation unit onboard the jet may determine the slant range of the target from the elevation and the altitude of the jet.

Abstract: In an embodiment, a quantity smoother includes a first stage and a second stage. The first stage is operable to receive a sequence of raw samples of a quantity and to generate from the raw samples intermediate samples of the quantity, the intermediate samples having a reduced level of fluctuation relative to the sequence of raw samples. The second stage is coupled to the first stage and is operable to generate from the intermediate samples resulting samples of the quantity, the resulting samples having a reduced level of fluctuation relative to the sequence of intermediate samples. For example, such a quantity smoother may be part of a target-ranging system on board a fighter jet, and may smooth an error in an estimated target range so that the fighter pilot may more quickly and confidently determine in his head a range window within which the target lies.

Abstract: In an embodiment, an apparatus includes a detector, direction finder, receiver, and range finder. The detector is operable to detect a target, and the direction finder is operable to determine a first direction to the target from the apparatus. The receiver is operable to receive a second direction to the target from a remote object, and the range finder is operable to determine from the first and second directions a range of the target from the apparatus. For example, the apparatus may be a first fighter jet, and the remote object may be a second fighter jet. By using directional information from both the first and second jets, a computer system onboard the first jet may compute a range to the target from the first jet more quickly and more accurately than by using directional information from only the first jet.

Abstract: In an embodiment, a coordinate determiner is operable to identify at least first and second surfaces that each approximately intersect an object, and to determine at least two approximate coordinates of the object from the first and second surfaces, where at least one of the surfaces is nonplanar. For example, if the coordinate determiner is disposed on a fighter jet having at least to short-baseline-interferometers (SBIs), then two surfaces may be the surfaces of two cones having two of the SBIs as respective vertices, the object may be a close-in target, and the coordinate determiner may determine the azimuth and elevation of the target from the cone surfaces. Furthermore, the coordinate determiner or another computation unit onboard the jet may determine the slant range of the target from the elevation and the altitude of the jet.

Abstract: Kalman gain is used to calculate range accuracy for a passive angle-of-arrival determining systems, most notably for short-baseline interferometry, in which Kalman gain after arriving at a minimum proceeds to within a predetermined fraction or percent of zero gain, at which time the range estimate accuracy is known.

Abstract: In an embodiment, a quantity smoother includes a first stage and a second stage. The first stage is operable to receive a sequence of raw samples of a quantity and to generate from the raw samples intermediate samples of the quantity, the intermediate samples having a reduced level of fluctuation relative to the sequence of raw samples. The second stage is coupled to the first stage and is operable to generate from the intermediate samples resulting samples of the quantity, the resulting samples having a reduced level of fluctuation relative to the sequence of intermediate samples. For example, such a quantity smoother may be part of a target-ranging system on board a fighter jet, and may smooth an error in an estimated target range so that the fighter pilot may more quickly and confidently determine in his head a range window within which the target lies.

Abstract: A method of two-source passive ranging comprising the steps of determining the coordinates of a first position and a second position wherein a first soldier or ground vehicle is located at the first position and a second soldier or ground vehicle is located at the second position; determining individual angles between said first and second positions and a radio frequency source; and using individual single-angle accuracy values to estimate the range from the first and second positions to the radio frequency source.

Abstract: Kalman gain is used to calculate range accuracy for a passive angle-of-arrival determining systems, most notably for short-baseline interferometry, in which Kalman gain after arriving at a minimum proceeds to within a predetermined fraction or percent of zero gain, at which time the range estimate accuracy is known.

Abstract: In an embodiment, an apparatus includes a detector, direction finder, receiver, and range finder. The detector is operable to detect a target, and the direction finder is operable to determine a first direction to the target from the apparatus. The receiver is operable to receive a second direction to the target from a remote object, and the range finder is operable to determine from the first and second directions a range of the target from the apparatus. For example, the apparatus may be a first fighter jet, and the remote object may be a second fighter jet. By using directional information from both the first and second jets, a computer system onboard the first jet may compute a range to the target from the first jet more quickly and more accurately than by using directional information from only the first jet.

Abstract: A method of two-source passive ranging comprising the steps of determining the coordinates of a first position and a second position wherein a first soldier or ground vehicle is located at the first position and a second soldier or ground vehicle is located at the second position; determining individual angles between said first and second positions and a radio frequency source; and using individual single-angle accuracy values to estimate the range from the first and second positions to the radio frequency source.

Abstract: A method and system to rapidly, passively, range and track maneuvering airborne emitters (enemy targets and threats) for tactical fighters using batch based recursive estimators for track initialization and track maintenance that includes providing information processing that has angle and signal amplitude data, threat database, and feedback from pilot cue analysis. The system includes pilot cue analysis which computes airborne emitter (target and threat) heading and corresponding accuracy to determine if sufficient accuracy is available to present the pilot with proper pilot cue options. The first stage is a range bank also called a compound parallel hypothesis evaluator and the second stage is an interactive multi-model. Both stages provide for the output of the algorithm to be a range measurement and an associated confidence factor. The algorithm inputs azimuth angle elevation angle and range and is capable of inputting data from three different data pre-processors (i.e., sensor data fusion).

Abstract: A decision aid for use in the defense of a combat ground vehicle which includes a track fusion element, a threat typing element, threat prioritization element, and a countermeasures (CM) selection element.

Abstract: A method and system to rapidly, passively, estimate target range, speed and heading for non-maneuvering and maneuvering radio frequency airborne emitters (enemy targets and threats) for tactical fighters using batch based recursive estimators for track initialization and track maintenance that includes providing information processing that operates on interferometer cosine (cone angle) measurements, and estimated SNR (signal-to-noise ratio) data, threat database, and feedback information from pilot maneuver cue algorithm. The present method will initialize airborne tracks using varying degrees of real time and a priori information to quickly estimate coarse airborne emitter heading using real time interferometer cosine (cone angle) measurements and provide pilot aircraft maneuver cues that will accelerate passive range (target speed and heading estimates) convergence.

Abstract: A decision aid for use in the defense of a combat ground vehicle which includes a track fusion element, a threat typing element, threat prioritization element, and a countermeasures (CM) selection element.

Abstract: A method and system to rapidly, passively, estimate target range, speed and heading for non-maneuvering and maneuvering radio frequency airborne emitters (enemy targets and threats) for tactical fighters using batch based recursive estimators for track initialization and track maintenance that includes providing information processing that operates on interferometer cosine (cone angle) measurements, and estimated SNR (signal-to-noise ratio) data, threat database, and feedback information from pilot maneuver cue algorithm. The present method will initialize airborne tracks using varying degrees of real time and a priori information to quickly estimate coarse airborne emitter heading using real time interferometer cosine (cone angle) measurements and provide pilot aircraft maneuver cues that will accelerate passive range (target speed and heading estimates) convergence.