WO2002045048A1

WO2002045048A1 - Landing and navigating system with virtual representation of the immediate surroundings

Info

Publication number: WO2002045048A1
Application number: PCT/CH2001/000686
Authority: WO
Inventors: Luca Carlino; Enzo Carlino; Tino Perucchi; Beat Ackermann; Stefano Azzalin
Original assignee: Karen Sa
Priority date: 2000-11-30
Filing date: 2001-11-26
Publication date: 2002-06-06
Also published as: AU2002223353A1

Abstract

The invention concerns a landing system enabling navigation and landing by supplying a virtual image of the immediate surroundings, obstacles, other vehicles, ground navigating stations (VOR, NDB, and the like), standard reporting points, landing and take-off procedures with standard instruments and the trajectory to follow.

Description

title

Landing and navigation system with virtual representation of the environment

Technical area

The present invention is part of display systems for aircraft, helicopters and hybrids (tilt rotor), more particularly virtual display systems which provide a video display based on the virtual reconstruction of the environment. The main field of use of this system is takeoff, flight, landing in adverse weather conditions with the aim of simplifying the procedures used by these subjects.

State of the art

The procedure of the 'Instrumental Landing System' (ILS) is, at present, identical for the planes and the helicopters. This causes a traffic jam effect due to the reduced speed of helicopters. In addition, the indication of the instruments allowing the landing is not very user-friendly.

Detailed presentation of the invention

This visualization system allows takeoff, flight and landing by providing a virtual image of the environment, obstacles, other vehicles and the path to follow.

The improvements brought by this system are mainly: + The on-board installation required is reduced compared to other systems and can be carried on any helicopter or plane, without weight and volume constraints. + The system can be used without and with installation on the ground. The installation on the ground is in any case less complex than the existing ones and it can be installed where traffic management is required. + Since until now the landing procedure is identical for helicopters and airplanes, a traffic jam effect can occur in the landing zone, due to the large difference in speed. This same problem occurs poses during takeoff and navigation. The system therefore proposes to separate the procedures, in order to free up the time and space occupied by the helicopters. To achieve this, it is possible to exploit the performance of the helicopter, such as a very low landing speed and hovering. This allows, on the one hand, to land manually with almost zero visibility and anywhere and, on the other hand, to redefine the concept of instrument flight.

Starting from a 3D model of the terrain and obstacles, this system reconstructs and displays the pilot's view in real time on a virtual screen mounted on the helmet (HMD: Helmet

Mounted Display).

During takeoff, the system visualizes the environment, the other vehicles and the trajectory to follow - not necessarily straight - in three dimensions. During the flight, 3D visualization of the terrain, obstacles (high voltage cables, antennas, etc.) and the trajectory allows the flight to be carried out safely. During the landing phase, the pilot can benefit from the same display details as on take-off.

The system described up to this point makes it possible to land and take off with visibility reduced to a minimum, in any location (airports, heliports, aircraft ports, hospitals, mountain huts, golf practice, etc.).

The system mounted on a helicopter makes it possible to calculate the parameters necessary for the reconstruction of the virtual image and for communication with other fixed and mobile stations. The parameters for positioning are calculated using information received from the DGPS, an inertial platform, a radio altimeter, an altimeter and a system that measures the position of the head of the pilot. However, interfaces to instruments providing other information (air speed, vertical speed, heading, weather radar, etc.) are planned.

The system is equipped with two radio interfaces for communication between the different vehicles and for communication with the fixed station. Separation of airport traffic is guaranteed with multiple CDMA access (division multiple access code). Each airport has its own code which is known by the systems on board helicopters.

This interface is part of a wireless network which connects all fixed and mobile equipment. This network allows the exchange of information on the positioning of other vehicles and instructions from the centralized fixed control station, but not necessarily present. Each member has a unique address allowing them to identify themselves and label their messages. The usefulness of this radio interface is to be able dynamically update the image from the pilot's point of view, by adding objects located in the same airspace, and a possible trajectory to guide the pilot in his landing. Messages received by other members of the wireless network are used for this update.

All the information necessary for viewing the scene is recorded in a database containing the description of the terrain and a database for obstacles. It is possible to update the obstacle database using the radio interface.

When the DGPS signal is present, the position of the helicopter is calculated using the information thus received. Since the frequency of arrival of information from a DGPS is too low for real-time refreshment, an inertial platform is used to receive the necessary parameters and thus allow interpolation of the flight path. In the event of a DGPS signal loss, position measurement is guaranteed with information from the inertial platform alone or by combining it with data from additional instruments.

The ground station, commanded by airport staff, is responsible for the synchronization of air traffic. Depending on the type of message received from the helicopter

(intention of landing, passage, takeoff, emergency, etc.), it intervenes on the display system, either by proposing a trajectory to follow, or by sending messages to display.

The accuracy of positioning during the landing phase depends on the presence of the station on the ground. The precision guaranteed with DGPS (1m) is improved to 1 cm by using the functionalities of the ground station.

The on-board system can also be connected to the flight director for calculating data for the autopilot.

The on-board system has a command interface for configuring and controlling various display and flight parameters: planning and display of the trajectory of a flight in three dimensions, display of a 'moving map', display of the rear view to guarantee a 360 ° view, display of flight parameters and the trajectory imposed by the ground station.

Realization of the invention

The position is calculated using the DGPS position information (Figure 1, block 1). This position is available a maximum of 5 times per second. The platform inertial form (Figure 1, block 2) provides the information necessary to know the speeds in the three axes and the coordinates, in order to be able to interpolate the points until the next DGPS message. The inertial platform also provides the inclinations in the three axes which are thus used for the display and the transposition of the speeds on the reference frame.

If the DGPS information is missing, only the information from the inertial platform, combined with the other instruments, is used to calculate the position. If the helicopter is hovering, information from the inertial platform is used to filter the position jump caused by the DGPS error.

The radio altimeter (figure 1, block 3) allows, as a first functionality, to check the height given by the DGPS or to replace it in case of loss of the DGPS signal.

The sensors for measuring the position of the head (Figure 1, block 4) allow the display to be adapted according to the pilot's real view.

All these parameters and those added as an option (figure 1, block 13) are connected to the calculation system from the point of view (figure 1, block 9).

The command interface (Figure 1, block 5) is used to configure and control the on-board system. The command interface makes it possible to configure and control various flight display parameters: planning and display of the trajectory of a flight in three dimensions (Figure 2), display of a moving map (Figure 3), display of the rear view to guarantee a 360 ° view (figure 3), display of flight parameters (figure 3), application or not of the texture (figure 4) and the trajectory imposed by the ground station

(figure 2).

The control display (Figure 1, block 8) is shown as the display interface for the control interface.

All control of the system is centralized at one point (Figure 1, block 10).

The system contains a database including terrain modeling. Depending on the position of the helicopter, the display part (Figure 1, block 11) dynamically loads the corresponding part when the pilot sees the database.

The obstacle database is used to display interesting obstacles and points

(airport, hospitals, etc.). Its information is updated dynamically and can be loaded from the ground station (figurel, block 14).

The virtual scene is displayed with a virtual screen mounted on the pilot's helmet (Figure 1, block 12). This screen is transparent and thus allows to have the real image and virtual superimposed. In this way, the pilot can take advantage of features such as viewing obstacles even in favorable weather conditions. Communication (Figure 1, blockβ) between members of the wireless network is based on a concurrent access protocol, detecting possible collisions (between messages). Each vehicle sends its position, flight direction, speed and identification with a given interval, so that all vehicles know the positions of others in their immediate environment (range of the radio interface). This information will be used to add the vehicles to the scene.

Separation of airport traffic is guaranteed with multiple CDMA access (division multiple access code). Each airport has its own code which is known by the systems on board helicopters. The ground station establishes a connection with the vehicle the first time it receives information about its position. This establishment attempt is repeated if the vehicle does not complete the request using the station's CDMA code.

The communication system with the ground station allows the exchange of information on the trajectory to be followed, new obstacles, modeling of the airport in question and any information related to the location.

List of images

Figure 1 shows the block diagram of the on-board system mounted on the helicopter or aircraft.

Figure 2 shows a screenshot with a 3D trajectory determining the path to follow to land.

Figure 3 shows a screenshot of the moving map and the rear view with the texture applied.

Figure 4 is a screenshot showing a terrain without texture applied with the visualization of an obstacle (transport cable).

Figure 5 is a screenshot of the model of some buildings without texture.

Claims

claims

Preamble

1) A method of navigation on board an airplane or a helicopter using a pilot's vision reconstruction system, in real time, making it possible to take off, fly and land in unfavorable meteorological conditions. using:

• acquisition of the geographic position of the vehicle in real time;

• real-time display of a virtual world on a transparent screen mounted on the helmet;

• a field database containing all the information necessary for rendering the image;

• a database of obstacles;

• one or more textures which allow a realistic representation.

2) Method according to claim 1, characterized by

• the introduction of the 3D trajectory to follow

3) Method according to one of the preceding claims, characterized by

• display of the bottom view

• rear view display

• display of flight information

4) Method according to one of the preceding claims, characterized by removing the texture of said image, in order to improve the perception of the morphology of the terrain

5) Method according to one of the preceding claims, characterized by the exchange of information concerning the position between the vehicles

6) Method according to one of the preceding claims, characterized by • exchange of specific take-off and landing information

• exchange of information specific to the state of the landing site

7) Method according to one of the preceding claims, characterized by dynamic updating of the obstacle database

8) Method according to one of the preceding claims, characterized by the combination and interpolation between different position measuring instruments

9) Method according to one of the preceding claims, characterized by highlighting obstacles which are potentially sources of collision

10) Method according to claim 2, characterized by controlling the autopilot using the proposed trajectory

11) Method according to one of the preceding claims, characterized by

• means for measuring the current position of the vehicle

• sensors to acquire the current situation of the vehicle

• sensors to measure the current head position

• a control panel forming part of the man / machine interface

• a control display as part of the man / machine interface

• an automatic radio communication system between vehicles to exchange the position information of the vehicles in question

• an automatic radio communication system between vehicles and the fixed central

12) Method according to one of the preceding claims, characterized by a fixed central system, placed at places of interest to determine the path to follow and the obstacles to report