The method carries out a measurement of the distance from the ground of an aircraft by undertaking the emission of waveforms making it possible to obtain, after demodulation, of the signals received in return and sampling of the demodulated signals at a frequency F.sub.éch, two signals E*.sub.0(t) and E*.sub.1(t), taking the form of two frequency ramps, of respective slopes K.sub.0 and K.sub.1, of respective passbands B.sub.0 and B.sub.1 and of respective durations T.sub.E0 and T.sub.E1, the N-point FFT spectral analysis of which is carried out. The values of the durations T.sub.E0 and T.sub.E1 as well as those of the passbands B.sub.0 and B.sub.1, are defined in such a way as to be able to determine, on the basis of the spectra of the signals E*.sub.0(t) and E*.sub.1(t), a measurement of non-ambiguous distance d.sub.1 covering the maximum distance d.sub.max to be instrumented and an ambiguous distance d.sub.0 exhibiting the desired distance resolution. The distance d to be measured being determined by combining these two measurements.

A system and method for augmenting synthetic vision system (SVS) databases with spectrum diverse features that are matched to the observations of natural scenes derived from non-visible band sensors. The system correlates sensor output with a-priori information in databases to enhance system precision and robustness. Multiple diverse sensors image naturally occurring, or artificial features (towers buildings etc.) and store the multi-spectral attributes of those features within the enhanced multi-spectral database and share the information with other systems. The system, upon “live” observation of those features and attributes, correlates current observations with expected fiducial observations in the multi-spectral database and confirms operation, navigation, precise position, and sensor fidelity to enable autonomous operation of an aircraft employing the system.

A system including an aircraft. A phased array may be configured to transmit electromagnetic (EM) energy toward rotor blades and receive EM energy in a direction from the rotor blades. A processor may be configured to: determine or obtain rotor blade information; determine or obtain aircraft information; based on the rotor blade information and the aircraft information, determine (a) a time to transmit EM energy or receive EM energy and (b) an angle to transmit EM energy or receive EM energy; and based on the rotor blade information and the aircraft information, control the phased array to adjust a beam pointing angle and to transmit EM energy for a duration at the beam pointing angle. The phased array may be configured to transmit EM energy for the duration at the beam pointing angle, wherein the transmitted EM energy is configured to reflect off a rotor blade toward a target.

A system for augmenting 360-degree aspect monostatic radar cross section of an aircraft. The system may comprise a pair of pods mountable on opposing wing tips of an aircraft and each having a pod housing with an elongate body tapering forwardly to a nose and rearwardly to a tail. Each pod may comprise a forward SDL disposed within the nose, a rear SDL disposed within the tail, and a pair of mid-body SDLs disposed within a mid-section of the pod housing. The SDLs may be arranged within the pods to reflect radiation and provide coverage around the aircraft over a region of about 360 azimuth degrees. Each SDL may comprise radar absorbing material located on an interior reflective surface, and portions of the elongate bodies may be constructed of radome material. The SDLs may be Luneburg lens having diameters of at least approximately 8-inches.

Methods, apparatuses, and systems for predicting radio altimeter failures are provided. An example method may include determining a first plurality of altitude values associated with a first radio altimeter, determining a second plurality of altitude values associated with a second radio altimeter, calculating a first level feature based at least in part on the first plurality of altitude values and the second plurality of altitude values, and determining a radio altimeter failure indicator based at least in part on the first level feature.

Methods, apparatuses, and systems for predicting radio altimeter failures are provided. An example method may include determining a first plurality of altitude values associated with a first radio altimeter, determining a second plurality of altitude values associated with a second radio altimeter, calculating a first level feature based at least in part on the first plurality of altitude values and the second plurality of altitude values, and determining a radio altimeter failure indicator based at least in part on the first level feature.

An apparatus interfaces with a light stanchion associated with a runway. The apparatus can include a first interface for attaching to the light stanchion, second interface for attaching to runway light, and a radar reflective member. The radar reflective member can be a corner reflector. The radar reflector can be part of set of reflectors arranged in accordance with visual approach slope indications or precision approach path indications.

A method of avoiding Controlled Flight Into Terrain (CFIT) involves a step of equipping an aircraft with a radar based sensor positioned in an angular orientation directed forward and down, so as to detect ground objects ahead of the aircraft. The radar must have a range of at least 10 Kilometres. A processing unit monitors the radar 5 based sensor. A display remains in an inactive mode until the radar based sensor detects a ground object meeting predetermined parameters. Upon the radar based sensor detecting a ground object the processing unit is programmed to switch the display to the active mode and display a graphic representation of the ground object. The method puts the pilot on alert with an 10 accentuated and focused warning in sufficient time to take appropriate evasive action to avoid a ground obstacle.

A method of avoiding Controlled Flight Into Terrain (CFIT) involves a step of equipping an aircraft with a radar based sensor positioned in an angular orientation directed forward and down, so as to detect ground objects ahead of the aircraft. The radar must have a range of at least 10 Kilometres. A processing unit monitors the radar 5 based sensor. A display remains in an inactive mode until the radar based sensor detects a ground object meeting predetermined parameters. Upon the radar based sensor detecting a ground object the processing unit is programmed to switch the display to the active mode and display a graphic representation of the ground object. The method puts the pilot on alert with an 10 accentuated and focused warning in sufficient time to take appropriate evasive action to avoid a ground obstacle.

A weak target detection method includes transmitting a plurality of frequency modulated continuous wave signals during rotation of a microwave radar sensor, receiving a plurality of echo signals reflected by a weak target, accumulating the plurality of echo signals in a beam width of the microwave radar sensor to obtain an accumulated echo signal, and determining position information of the weak target according to the accumulated echo signal.