Techniques for allowing a vehicle equipped with at least one radar to take-off and land using radar return images of a landing site. The at least one radar generates radar return image(s) of the landing site, specifically of reflective symbols attached to the landing site, allowing the vehicle to orient itself to the landing site and providing information specific to the landing site. Position and velocity in relation to a landing site can be determined using at least one radar and a guidance and landing system. Using the position and velocity information, the guidance and landing system can guide the vehicle to and from the landing site and/or determine whether an obstacle requires the use of an alternate landing site.

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.

A synthetic radio altimeter system is provided. At least one sensor is used to generate sensor data that is used at least to determine a then current vehicle location. At least one controller is configured to determine an elevation of terrain under a vehicle based on the determined then current location of the vehicle and terrain information in the terrain database. The at least one controller is further configured to determine a height of the vehicle above terrain based at least in part on the determined elevation of terrain under the vehicle and the sensor data. The at least one controller further configured to augment the determined height of the vehicle above terrain with at least in part navigation database information when the vehicle is near one of a travel path origin and a travel path destination. The height above terrain may also be augmented based on a navigation radio.

A synthetic radio altimeter system is provided. At least one sensor is used to generate sensor data that is used at least to determine a then current vehicle location. At least one controller is configured to determine an elevation of terrain under a vehicle based on the determined then current location of the vehicle and terrain information in the terrain database. The at least one controller is further configured to determine a height of the vehicle above terrain based at least in part on the determined elevation of terrain under the vehicle and the sensor data. The at least one controller further configured to augment the determined height of the vehicle above terrain with at least in part navigation database information when the vehicle is near one of a travel path origin and a travel path destination. The height above terrain may also be augmented based on a navigation radio.

A vehicle location accuracy enhancement system is provided. A digital active phased array radar is configured to generate a profiled terrain including terrain altitude information. A controller is configured to implement operating instructions in memory to conduct profile matching between the generated profiled terrain from the at least one digital active phased array radar and terrain altitude profile information in a terrain database to determine profiled location solutions. The controller is further configured to at least augment sensor location solutions from at least one other location determining system, including a GNSS, with the profiled location solutions to enhance accuracy of the sensor location solutions. The controller is also configured to determine location errors in the GNSS based on the profiled location solution and to broadcast the determined location errors.

A vehicle location accuracy enhancement system is provided. A digital active phased array radar is configured to generate a profiled terrain including terrain altitude information. A controller is configured to implement operating instructions in memory to conduct profile matching between the generated profiled terrain from the at least one digital active phased array radar and terrain altitude profile information in a terrain database to determine profiled location solutions. The controller is further configured to at least augment sensor location solutions from at least one other location determining system, including a GNSS, with the profiled location solutions to enhance accuracy of the sensor location solutions. The controller is also configured to determine location errors in the GNSS based on the profiled location solution and to broadcast the determined location errors.

Disclosed is an obstacle avoiding method and apparatus for an unmanned aerial vehicle based on a multi-signal acquisition and route planning model. The method comprises: conducting signal acquisition processing on a first environmental area to obtain an initial millimeter-wave radar signal, an initial laser radar signal, an initial image signal and an initial ultrasonic signal; generating an initial three-dimensional environmental model according to a preset dynamic environment real-time modeling method; acquiring a motion parameter and a body shape parameter of the unmanned aerial vehicle and inputting the parameters into an initial route planning model corresponding to the initial three-dimensional environmental model based on a genetic algorithm to process so as to obtain an output of the initial route planning model; judging whether the output is capable of avoiding an obstacle; if yes, generating an obstacle avoiding flight instruction to require the unmanned aerial vehicle to fly through the first environmental area.

Systems, computer-implemented methods and/or computer program products that facilitate landing on emergency or unprepared landing strip in low visibility condition are provided. In one embodiment, a system 100 utilizes a processor 106 that executes computer implemented components stored in a memory 104. A selection component 108 selects candidate spaces from a navigation database or machine vision data for landing an aircraft. A guidance component 110 guides landing the aircraft on a landing strip from among the candidate spaces in low visibility condition.

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.