Wifi aircraft antenna

Internet access started to appear on aircraft only in the last 20 years. It expanded commercially from with a number of international airlines, but was closed in , citing limited market uptake. It had been offering satellite-based inflight phone systems since the s. These early systems were based on low bandwidth satellite communications. As such, they were slow and expensive.

Technology has improved since then, and costs have lowered. Ground-based systems have been developed too, and satellite systems improved.

Today these are the two different ways of providing inflight internet — and we will discuss how each one works separately. Ground antennas based systems offered better speeds than the early satellite systems and were the next to be developed. Air to ground ATG systems work by installing antennas on the base of the aircraft fuselage. These then pick up a signal from a ground-based tower. As the aircraft flies over ground, the system switches to the closest antenna, much like how a normal cell phone system operates.

The signal is spread through the aircraft using a series of WiFi access points, usually concealed with their wiring behind the wall panels. Typical speeds offered are around 3Mbps. The antenna then allows communications with the inside of the aircraft, for example with a wireless network inside the aircraft.

In these two cases, the reflector makes it possible to attenuate the signals in one direction or in the other and, simultaneously, to fulfill the role of reflector to improve the gain of the antenna in the opposite direction. It also is possible to install two antennas, placed on both sides of the heating layer, to allow two simultaneous communications, one to the outside and the other to the inside of the aircraft. The antenna preferably is used in transmission and reception, covering the frequency bands assigned to the wireless technologies.

It is recalled that the WiFi-type communication technologies provide an extensive coverage on the ground. It therefore is possible, with the aid of quasi-directional antennas, to connect easily to a corresponding type of network. Small-size antennas incorporated into the glazings of the cockpit or the cabin windows therefore may be used to implement a connection with access points on the ground.

The presence of conductive materials inside the glazings allows these antennas to be quasi-directional to the outside of the airplane with a small likelihood of interfering with the on-board equipment items. It also is possible to use these antennas, according to the composition of the glazing, for covering the inside of the airplane with wireless technologies. These antennas also may be set up in windows or cockpit glazings. In this way, the communication devices according to the invention make it possible to replace or supplement an existing WiFi-type antenna.

When the aircraft is on the ground, near a communication antenna, the location of the access point is not known in advance. It therefore is possible, in particular, to use the communication device according to the invention to supplement an existing antenna when the ground base station is in a zone in front of the aircraft, poorly covered by same.

As shown, aircraft is parked near an infrastructure on the ground, here a jetway , so that a door of aircraft is opposite the end of jetway Aircraft comprises a data-processing system taken on board not shown , for example with the maintenance system, able to exchange data with a data-processing system on the ground Aircraft comprises a WiFi- or WiMax-type antenna , here incorporated into the glazing of the cockpit.

Antenna is connected to the data-processing system of aircraft through an appropriate communication interface. An access terminal comprising an antenna is positioned on the ground, for example in front of aircraft The radio module not shown associated with antenna is connected to network of airport terminal by a link , here a wired link.

Network is connected, for example, to local network of the airline company via an Internet-type network through firewalls called firewall in English terminology. Similarly, an antenna connected to the network of the local company may be placed on a structural element, movable or not, removable or not, of a maintenance hangar, in order to be positioned near aircraft comprising antenna when the aircraft is in the maintenance hangar.

As illustrated, the glazings comprise a plurality of glass layers, generally three, here referenced - 1 , - 2 and - 3. Glass layer - 3 , intended to be placed toward the outside of the aircraft, often has a thickness of three millimeters. Glass layer - 1 , intended to be placed toward the inside of the aircraft, as well as inner glass layer - 2 , generally have a thickness of eight millimeters. Inset layer , placed between glass layers - 1 and - 2 , may have a thickness of one millimeter.

Inset layer , placed between glass layers - 2 and - 3 , generally has a thickness of about eight millimeters. The reflective layer, here partial, is implemented with heating film comprising, for example, tin-doped indium oxide, also called ITO. Heating film is positioned between inset layer and glass layer - 3. Furthermore, the edge of the glazing is formed by a section comprising elements and generally made of polysulfide rubber PR and silicone, used to fasten the glazing.

The heating film may be obtained, for example, according to the method described in the patent FR 2 The glazings used to form the side glazings cockpit side glazings or cabin windows are similar to glazing Nonetheless, the glass layers used, in particular glass layers - 1 and - 2 , have different thicknesses, for example six and five millimeters, respectively.

Furthermore, heating layer generally is located between glass layer - 2 and inset layer and not between inset layer and glass layer - 3. The heating film is used for de-icing of the front glazings and for defogging of the side glazings. The antenna may be set up directly in the glazing during its manufacture by taking advantage of its multilayer construction. Nonetheless it should be noted that, because of the superposition of the layers forming the front glazings and the position of the heating film, it is difficult to insert an antenna between the heating film and the outside surface of these glazings.

Nevertheless, the insertion of an antenna between the heating film and the inside surface of these glazings allows a wireless communication in the cockpit, for example according to a network architecture of WLAN acronym for Wireless Local Area Network in English terminology or WPAN acronym for Wireless Personal Area Network in English terminology type.

In the side glazings, the distance between the outside part of the glazing and the heating part is sufficient to allow the setting up of an antenna between a glass layer and a Polyurethane inset layer.

This antenna takes advantage of the heating part as a reflector in order to improve the gain and the directivity of the antenna while minimizing disruptions of equipment items located in the cockpit.

The setting up of an antenna in each side glazing makes it possible to take advantage of a diversity effect which, according to the location of the access points, makes it possible to take advantage of the best signal received by one or the other antenna.

Furthermore, the presence of a reflective layer in the glazing makes it possible to attenuate the radiation in one or the other direction. In this way it is possible to cover the cockpit alone or to radiate toward the outside of the airplane without disrupting the enclosure of the cockpit. This attenuation is more or less effective according to the frequency band used.

Like the glazing illustrated on FIG. Heating film here is inserted between glass layer - 2 and inset layer side glazing. The edge of glazing furthermore is formed by a section comprising elements and , enabling its fastening.

An antenna is inserted between inset layer and glass layer - 3. In this way antenna is positioned between the heating film and the outside surface of glazing Antenna here is connected to a connector making it possible to connect it to a ground of the aircraft as well as to a communication system not shown via connection The inserted antenna may be a narrow- or wide-band antenna with vertical, horizontal or circular polarization.

This antenna may be, in particular, an equiangular spiral antenna such as the one shown on FIG. The heating film used for defogging serves as a reflector. In this way the gain of the antenna is enhanced and disruptions sustained inside the cockpit are reduced. Alternatively or additionally, antenna may be inserted between inset layer and glass layer - 1 in order to allow a wireless communication inside the aircraft. These include flush antennas located under the empennage that look like flat plates, and antennas that have thick wires that protrude straight down from the empennage and then turn towards the tail of the plane.

Both of these types of marker beacon antennas have proven to be very successful. Almost always found on the vertical tail, nav antennas come in three main types.

The cat whisker has several rods jutting out from each side of the stabilizer at degree angles. A second type, the dual blade, has antennas on either side of the tail.

A third type of nav antenna, the towel bar, is a balanced loop antenna that can easily receive signals from all directions.

Towel bar antennas are found on both sides of the tail of the airplane and are often required for area navigation RNAV systems.

These antennas, which look like six-inch-square plates, are placed on the bottom of the aircraft. They are usually either a single- or dual-antenna system, and the radar signal is transmitted straight down and literally bounces off of the ground. Radio altimeters include high frequencies and, therefore, require a secure electrical bond with the skin of the airplane.

You can determine the distance above the ground by measuring the time between the transmission of the signal and when the signal is received. Again, the secure bond of the antenna is a must; otherwise, the system talks to itself and causes false readings.

Utilized mostly for distance-measuring equipment DME and transponders, UHF aircraft antennas are only around four inches long and are always found on the bottom of the aircraft. They can be used for both DMEs and transponders, and their two main types are blade and spike antennas. Spike antennas should only be used for transponders, while blade antennas work best with DMEs. When the landing gear of an airplane is down, it can shadow UHF antennas because of their small size, and spike antennas are even prone to trouble due to things like errant scrub brushes.

Biannual transponder checks are also highly recommended, in part because blade antennas can have oil and water buildup and, therefore, may distort the transmitted signal. About the Author Editorial Team.