An airfield visibility monitoring system may include a measurement unit to emit one or more pulses of electromagnetic radiation along an aircraft glideslope associated with a runway and detect backscattered radiation from the glideslope associated with the emitted pulses. The measurement unit may further determine round-trip times between emission of the one or more pulses and detection of the backscattered radiation. The system may further include a controller. The controller may determine values of a visibility metric for multiple distances from the measurement unit along the glideslope based on the detected backscattered radiation and round-trip times, determine values of the visibility metric for multiple altitudes based on the values of the visibility metric along the glideslope, and direct an airfield communication unit to broadcast values of the visibility metric for at least some of the altitudes.

Disclosed are methods, systems, and non-transitory computer-readable medium for landing a vehicle. For instance, the method may include: before a descent transition point, receiving from a service a landing zone confirmation including landing zone location information and an indication that a landing zone is clear; determining a landing flight path based on the landing zone location information; and upon the vehicle starting a descent to the landing zone using the landing flight path: receiving landing zone data from at least one of a radar system, a camera system, an altitude and heading reference system (AHRS), and a GPS system; performing an analysis based on the landing zone data to determine whether an unsafe condition exists; and based on the analysis, computing flight controls for the vehicle to continue the descent or modify the descent.

A surface-based transmitter system for assisting determination of vehicle location is presented. The system comprises a set of radio frequency (RF) transmitter nodes that, when deployed at different respective locations, are configured to output a sequence of respective RF pulses with a predefined inter-pulse delay between each pair of consecutive RF pulses in the sequence, wherein the pre-defined inter-pulse delay is longer than 1 microsecond. The set of RF transmitter nodes include at least a first RF transmitter node, a second RF transmitter node, a third RF transmitter node, and a fourth RF transmitter node, which are configured to output a first RF pulse, a second RF pulse, a third RF pulse, and a fourth RF pulse, respectively, of the sequence of RF pulses.

An apparatus is for use with an aircraft radar system having a radar antenna. The apparatus includes processing electronics configured to cause the radar antenna to emit radar pulses having a pulse width less than 6 microseconds and configured to receive radar data associated with signals associated with the radar antenna. The radar data is processed to identify centroids associated with indications of the runway lights for a runway in the radar data. A best fit analysis of the centroids is used to identify a runway centerline associated with the runway.

The system for aiding the landing of an aircraft on a landing runway of an airport equipped with an Instrument Landing System (ILS) corresponding to an axis of a predetermined approach, includes: an ILS signals receiver and a processing unit. The processing unit is configured to, when the ILS signals receiver) has not yet captured a Glide signal corresponding to a Glide axis of the approach as a function of items of information relating to the predetermined approach, acquired from a database, determine a protection volume in which there is no risk of the ILS signals receiver detecting a replica of the Glide signal; and when a current position of the aircraft is above the protection volume, inhibit the capture of the Glide signal by the ILS signals receiver and instruct the emission of an alert item of information in the cockpit of the aircraft.

A system for detecting airborne objects within a shared field of view is disclosed. The system includes a first transceiver and a second transceiver. The first transceiver is positioned in a first discrete location and has a first field of view that represents a detection area of the first transceiver and the second transceiver is positioned in a second discrete location and has a second field of view that represents the detection area of the second field of view. The first field of view and the second field of view intersect one another to create the shared field of view. Both the first transceiver and the second transceiver are both configured to emit an array of signals towards the shared field of view.

Autoland systems and processes for landing an aircraft without pilot intervention are described. In implementations, the autoland system includes a memory operable to store one or more modules and at least one processor coupled to the memory. The processor is operable to execute the one or more modules to identify a plurality of potential destinations for an aircraft; calculate a merit for each potential destination identified; select a destination based upon the merit; and create a route from a current position of the aircraft to an approach fix associated with the destination that accounts for the terrain characteristic(s) and/or obstacle characteristic(s). The processor can also cause the aircraft to traverse the route, determine a final approach segment associated with the route; identify terrain characteristic(s) and/or obstacle characteristic(s) associated with the final approach segment; and determine an adjusted final approach segment accounting for the terrain characteristic(s) and/or obstacle characteristic(s).

A system for calibrating a transmitting unit includes an arrangement of at least four transmitting units. A first transmitting unit has stored position data with respect to a setpoint position of the first transmitting unit. The first transmitting unit is designed to emit a first transmission signal to each of the three remaining transmitting units, each of which is designed to receive the first transmission signal and, thereafter, to return a first response signal to the first transmitting unit. The first transmitting unit is designed to determine its relative position data with respect to the three remaining transmitting units on the basis of the first response signals returned and to detect a deviation between the stored position data and the relative position data determined and to carry out a calibration of a transmission parameter of the first transmitting unit on the basis of the detected deviation.

Autoland systems and processes for landing an aircraft without pilot intervention are described. In implementations, the autoland system includes a memory operable to store one or more modules and at least one processor coupled to the memory. The processor is operable to execute the one or more modules to identify a plurality of potential destinations for an aircraft. The processor can also calculate a merit for each potential destination identified, select a destination based upon the merit; receive terrain data and/or obstacle data, the including terrain characteristic(s) and/or obstacle characteristic(s); and create a route from a current position of the aircraft to an approach fix associated with the destination, the route accounting for the terrain characteristic(s) and/or obstacle characteristic(s). The processor can also cause the aircraft to traverse the route, and cause the aircraft to land at the destination without requiring pilot intervention.

An unmanned aerial vehicle (UAV) landing marker transmits a reply signal in response to receiving radar signals emitted by a UAV. The landing marker can include a passive transponder that emits the reply signal, with the reply signal being a harmonic of the fundamental frequency of the radar signal emitted by the UAV. The landing marker can also include a transmitter to transmit the reply signal. Additionally, the landing marker can include sensors to monitor the environment about the landing marker and this environmental information can be transmitted to the UAV as part of the reply signal.