DE102005031439A1 - Satellite linked simulation system is used to provide aircraft flight management to prevent mid air collisions - Google Patents

Abstract

The location and movement of aircraft (1) in airspace is monitored and controlled to avoid collisions. The system has communication (5) and navigation (4) satellites linked to aircraft satellite dishes (2) and to ground based units (6) linked to a simulations system (8). This also receives data from radar. The system simulates air conditions to provided early warning of potential collision situations.

Description

The The invention relates to a satellite-based warning system Collisions and traffic management of vehicles, such as aircraft.

to Traffic warning and collision avoidance in aviation are in aircraft board often TCAS II (Traffic Alert and Collision Avoidance System) systems installed. TCAS II permanently monitors the airspace and the pilots be in time before a threatening dangerous encounter with a approaching Aircraft warned. In critical cases, you may want to make meaningful fallback instructions be granted. The TCAS II system is one of virtually all airlines approved security system. For example, all in the US Airspace flying passenger aircraft with more than 30 seats with equipped with a TCAS II be.

Around Being recognized by an air traffic control system is a standard feature of the TCAS II of commercial aircraft a so-called transponder i.a. on two frequencies, namely 1030 MHz at query and 1090 MHz at the answer, various information, such as identifier, altitude and speed transmitted.

in this connection TACS-II uses this transponder principle for data acquisition. Two Antennas installed at the top and bottom of the fuselage spark in every second in all directions a question signal into the airspace. receives the transponder of another aircraft answers these signals, so answers its transponder depending on the design with the information removal, Flight direction and altitude.

Of the computer provided in the TCAS II calculated from the information received a rapprochement speed and the time to the point of closest approach (CPA: "Closest Point of Approach ") Time is for the further calculations relevant size. Only so is guaranteed that the pilot in case of a warning or avoidance instruction enough Time to react, regardless of speed, with which the planes move towards each other. In addition will dependent on from the altitude lengthens the reaction time, thereby the height-dependent power loss of engines.

Lies a potential threat, the TCAS II system sees four information and instruction levels, which in the cockpit visually and acoustically be reproduced / represented. Here is the protective field, which the TCAS II system builds around an aircraft, in the three dimensions limited. In general, it has a diameter of about 25 km and a height from about 2 km. The system keeps track of aircraft movements up to 45 aircraft in this shield, much of it for display can be brought. Here you can approach speeds up to 1200 knots (about 2220 km / h) and vertical approach speeds from 0 to 10,000 ft / min from the processor.

First if another aircraft enters the protective field, a Traffic information displayed. These appear on the navigation screens in the cockpit depending on the potential danger different symbols, only at the symbol RA (Resolution Advisory) indicated in the TCAS II system that there is an acute risk of collision. Here is the period of time until a possible collision between 15 and 35 seconds.

Additionally appears for example on the attitude display a maneuver display, which, depending on the situation, requires an immediate rise or fall; these Display is still supported by an acoustic signal. In In such a case, the cockpit crew obeys the resolution Advisory (RA) immediately and directs according to the maneuver display a climb or descent. This is in the indicated Example by a corrective RA, precautionary or preventive RA require no evasive maneuver, but ask the pilot to maintain the current flight path exactly.

If both planes over have the appropriate transponder, it comes with the TCAS II system to a coordinated resolution advisory, this is a short-term Flugwegänderung Both aircraft provided, and only avoidance maneuvers in vertical Direction. After the execution The Resolution Advisory will immediately return the pilots to their original one altitude back and inform the responsible Air traffic control center.

For this is to determine that the performance of a TCAS II system dependent of the transponder type of the approaching aircraft. Certain Transmit transponder no height information; for safety reasons then goes that TCAS II system assumes that the intruder at the same altitude is located and gives traffic information, an alternate instruction omitted. Aircraft without transponder with the device switched off or with some types of transponders of Russian design that do not recognize TCAS II stay for the warning system invisible, that means a warning or a Avoidance instruction is omitted.

The TCAS II system gives cockpit crew information, however unable to make a maneuver to perform yourself. Whether and how a Resolution Advisory will be followed, is in here the responsibility of the pilot.

In Cockpits of modern commercial aircraft are often more safety systems Installed. A share wind warning system warns of critical spinning winds. This protects one so-called stall warning the plane from stalling. A GPWS Ground Approach Warning System (Ground Proximity Warning System) reacts at too high a rate of approach to the ground with optical and acoustic signals.

Currently is being started on ADS-B (Automatic Dependent Surveillance Broadcast) systems switch. These aircraft-mounted systems send identification and position data. This new technology allows pilots in the cockpits and air traffic controllers on the ground with the air traffic a higher one Precision "to see", as it was previously possible. That in the introduction The purpose of the ADS-B system is to make flying safer and more efficient Allow use of the airspace.

at The ADS-B system is the exact position of an aircraft in the air above transmitted digital data link together with other data, such as airspeed, altitude and the information as to whether the aircraft is flying a curve rises or falls. ADS-B receiver, integrated in the aviation control system or aboard a other aircraft are installed, provide the users with a accurate reproduction of aviation in real time, both in the air as well as on the ground.

in the Difference to conventional Radar operates the ADS-B system at low altitudes and on the ground, so it can also be used to traffic on the runway and the runways of an airport to monitor. It is also effective in more remote areas or hilly terrain when there is no detection by radar or detection by radar is limited. One of the biggest advantages of the ADS-B system lies therein, the same information in real time (Real-time) both pilots in aircraft cockpits and air traffic controllers to transmit on the ground so that both "see" the same data packets.

The ADS-B system is based on a satellite-based global positioning system with which a precise position of an aircraft in the airspace too determine is. The system translates the position in a digital code, which with other information, such as aircraft type, its airspeed, its flight number and in turn, supplied with the information, whether the aircraft is a curve flies, rises or falls. Here is the digital code, all contains this information, Updated several times per second and from the plane on one discrete frequency sent, Other aircraft and ground stations Within about 150 miles receive the Datalink transmission and show the information on a computer screen. pilots in the cockpit see the air traffic on an in the cockpit accommodated Air Traffic Information Display (CDTI: Cockpit Display of Traffic Information). The air traffic controllers on the ground can use the ADS-B targets on their own regular See screen together with other radar targets.

apart from the ADS-B system just introduced is generally only an active and / or passive terrestrial Radar monitoring, isolated also performed with GPS position notification. However, there are in some parts of the world at all no terrestrial surveillance, although enough Satellites available would.

Mostly a radar check is carried out. Only be very limited Navigation data, such as position, passed, but without that Acceleration values and controller positions are integrated. However, impending collisions are not reliably predictable enough; On top of that, the data is not good enough. In addition, at best Positions and speeds determined, thus only in the short term linear predictions a trajectory or a ship route are possible.

task The invention is the aviation or shipping effectively to monitor and collisions between vehicles, such as aircraft or ships early to be able to prevent.

According to the invention This is the task with a satellite-based warning system for collisions and the traffic management of aircraft by the features achieved in the characterizing part of claim 1. Advantageous developments are the subject of dependent claims. About that In addition, the system can also be used to warn against collisions and for Traffic management used by ships instead of aircraft become.

According to the invention, a mode of transport, such as aviation or shipping, is a satellite navigation system, such as the Global Navigation Satellite System (GNSS), a satellite communication system and a computer simulation with expert systems provided. With this, non-linear predictions of a trajectory or a ship's route are also possible. Conventional radar monitoring devices, radio links, traffic management systems can be integrated into the system according to the invention for increasing the availability and reliability.

Farther also data of the current positions of the control units, weather data, Machine data and data via transmit the planned route or flight maneuvers. This gives a very precise simulation and prediction on the ground the spatial conditions feasible not only for a linear projection of trajectories, but also a nonlinear one Projection under consideration all data. Pending collisions can be so much more precise in the anticipated and prevented by course corrections.

The inventive system is beneficial in both aviation and shipping usable and in principle similar structured. The main difference, however, is that that the airspace is three-dimensional compared to the two-dimensional water surface is.

In This affects the number of parameters in each system the transmitted spatial Vectors and in terms of a simplified simulation and Kursprädiktion However, the critical periods in aviation are much shorter than in shipping. The following are these two application fields not distinguished, since, as already mentioned, the systems of the invention are basically the same.

Already Existing warning systems, such as the "Short Term Conflict Alert (STCA)" can be implemented Introducing the system according to the invention be significantly improved. STCA is based only on a relatively inaccurate Radar measurement in conjunction with a linear short-term prediction the trajectory. According to the invention However, it is characterized by very precise positioning of satellite navigation and additional Measurements taken from the aircraft, such as location, accelerations and control parameters. Such are not just linear predictions possible, but also non-linear, such as short-term curves and medium-term routes. The provided computer simulation can thus the whole air space Modeling and an expert system can use it to make decisions about warnings to meet.

In Connection to the worldwide available satellite navigation signals and a global satellite communications network thus an efficient system for a "Global Air Traffic Management (GATM) ". In particular, complex computer simulations and expert systems to prevent collisions can be so effectively organized globally become. Nevertheless, a redundant and regionally distributed design useful to the availability increase the system and maintain in case of error.

For terrestrial well supervised Territories, this system is a superposition and expansion, so to speak for conventional airspace monitoring. In other areas of the world, such as Africa, the oceans, without functioning soil monitoring This is the first time an efficient system for traffic management and created for collision warning. In any case, but one multiple security and enhanced Availability makes sense.

Also For example, if the routes appear conflict-free right now through the prediction short-term deviations already based on the control parameters very early be recognized. Especially in very dense airspace near congested Airports can the system of the invention help prevent accidents can be.

So that would have plane crash on 1.7.2002 at Überlingen / D with the system according to the invention with high probability can be prevented, and in particular because the Aircraft Accident Investigation has revealed that in addition to human The communication and navigation systems are also problematic were. The radar systems were partly inaccurate and effective Collision detection and warning system was not available. The TCAS anti-collision systems installed in the aircraft are such initially stated, only limited (locally) effective and their instructions were in this Case contrary to the instructions of the air traffic controller. In difference to an aircraft-to-aircraft communication at TCAS will be with the inventive system the airspace holistic and closer considered.

following the invention will be described in detail with reference to the drawings. Show it:

1 in a schematic representation of an exemplary overall architecture;

2 also in a schematic representation of an architecture in the aircraft;

3 a standardized data set with navigation vector;

4 a standardized record with Machine condition value;

5 in a basic representation the architecture on the ground including a simulation system;

6 a schematic representation of a non-linear route prediction with a collision prediction, and

7 in a schematic representation of the architecture of a machine simulation.

In the basic representation of an overall architecture in 1 is a schematically illustrated aircraft 1 reproduced on which two so-called satcom antennas 2 are attached, and that a navigation receiver 3 having. At the top of the in 1 are a total of three navigation satellites 41 to 43 and five communication satellites 51 to 55 shown. The communication between the communication satellites 51 to 55 is indicated by lines provided with two arrowheads, as well as the communication of, for example, the first and third communication satellites 51 and 53 by plane 1 over the Satcom antennas 2 , The navigation satellites 41 to 43 are constantly in communication with the aircraft, which is indicated by dash-dotted lines provided with two arrowheads, the arrowheads on the plane 1 accommodated navigation receiver 3 clues.

Through a radio-marked line with arrowheads at both ends, the communication between the aircraft and in the schematic architecture is three ground stations 61 to 63 indicated. The ground stations 61 and 63 communicate with the third and fifth communication satellites 51 and 53 , which in turn is indicated by arrowheaded lines. The three ground stations 61 to 63 are over a network 7 in contact with each other. The network 7 is a simulation system 8th is assigned, in which additional data, for example, from a radar monitoring can be fed.

In 2 an example of an aircraft installation is reproduced. The data from satellite navigation systems (Sat1 to Sat3) and data from other avionics devices 9 Such as radar transponders, RF navigation systems, TCAS, weather measurements, etc., are connected via a redundant connection network 10 in communication control devices 11 (Controller) fed. Here, the data records are prepared and via another redundant connection network 12 for transmission in the satellite communication network or optionally also by conventional radio (HF / HFDL, VHF / VDL). Redundancy is an important criterion here, so that faultless functioning is guaranteed even if individual components fail.

It can also several satellite navigation systems are combined, like GLONASS, GPS, Galileo, or multiple satellite communication systems, how Inmarsat, Iridium ... are used. Navigation receivers can continue with multiple antennas determine the position of the aircraft in space ("Satellite Compass"), which is an interesting Alternative and extension to magnetic compass and gyroscope is.

For a global "Global Air Traffic Management" (GATM), the data formats to be transmitted have to be standardized. According to the invention for this purpose is a record according to the embodiment in 3 makes sense, which has an aircraft identifier ID, a time stamp, a position vector POS {x ₁ , x ₂ , x ₃ } (from GNSS), a direction or position vector DIR {d ₁ , d ₂ , d ₃ } (by satellite compass and or a gyroscope), a velocity vector VEL {v ₁ , v ₂ , v ₃ }, an angular velocity vector VEL _red {ω ₁ , ω ₂ , ω ₃ }, an acceleration vector ACC _trans {a ₂ , a ₂ , a ₃ } , an angle acceleration vector ACC _red {w ₁ , w ₂ , w ₃ }, controller positions in a normalized scale, information about a planned route, for example, a polygon line, weather data such as wind, precipitation, etc. by means of sensors, and other data, for example from TCAS.

As This data can be determined in detail, for example by measurements using sensors, through calculations, etc. is known and therefore needs not to be specified here in detail. The knowledge of the Determination method and accuracies may u.U. later on the aircraft ID are taken into account in the simulation. On the entire record becomes a cryptographic digital signature formed the authenticity to guarantee the data. This is or should be prevented that attackers are aware and for sabotage purposes wrong data in the Feed the system. Using a Public Key Infrastructure (PKI), the based on digital X.509 certificates, the signature may be on the ground be verified. fake records will not be considered then rather, an alarm is triggered.

In addition to authenticity, the confidentiality of navigation data is important because they could also be misused for terrorist purposes. Therefore, the records are transmitted only with strong encryption or via encrypted communication channels. Multiple security layers make sense, so that in the case of a simple security vulnerability, the data is not immediately vulnerable. For example, an encryption of the satellite connection can be combined with a separa encryption of the data record.

possibly not all machines in the airspace are equipped with GNSS and satellite communications, for example, older ones Airplanes, sports planes or helicopters. Also the military air traffic is not necessarily about it detected. That's why it makes sense, even the data of conventional radar surveillance into the system. The additional flying objects are then Although not as well modeled as those with full data sets, but can at least in the collision prediction taken into account become.

For airlines and the maintenance teams, it is advantageous to transmit not only navigation data but also machine data of the aircraft. In 4 is an embodiment with aircraft ID, timestamp, aircraft type / serial number, machine record and other warning messages reproduced.

In 5 For example, an exemplary embodiment of a ground-based architecture including a simulation network is provided. The data sets containing the navigation vectors are transmitted via the satellite communication network and associated terrestrial networks into a real-time database (Block 13 ) for aircraft position and condition data. These data form the basis of a computer simulation, which, as it were, is a simulative image of airspace (Block 14 ). Data from conventional air monitoring and terrestrial radar systems (Block 15 ), which also includes flying objects that have not reported their position and existence via GNSS / satellite. From the current state, future constellations are then predicted on the basis of the data records.

Under consideration the state data, the change vectors, Regulator positions, route planning, weather data and aerodynamic (aircraft typical) Calculations can be a very accurate prediction in the short term respectively. Here, the prediction takes place considering the local weather conditions (wind), the aerodynamic flight behavior (type-specific) of the aircraft controller (standardized parameter vector), the position, velocity and acceleration measurement and the stored estimated flight route. Also in the longer term can using this data, to calculate estimated flight routes, although with coarser Resolution.

Furthermore, an expert system (block 16 ) for the prediction of possible conflicts, collisions and route deviations, from which possibly a warning to the network 17 is delivered. Such a warning may include status and warning messages to conventional airspace monitoring systems, conflict managers, and the pilots involved.

In 6 For example, such a nonlinear prediction is shown. Here, too, the difference to a simple linear prediction based on a current direction of flight can be seen. The current direction of flight can definitely represent a collision-free situation. However, according to the invention already a possible collision can be predicted, which results only from the acceleration vectors and the transmitted controller position.

An expert system 16 ( 5 ) within the computer simulation can automatically detect such critical situations and warn pilots and specially trained air traffic controllers. Correction maneuvers are thus much earlier and more targeted. The stored scheduled flight routes of all involved machines may also provide further information to the decision support expert system.

A further function that can be carried out according to the invention that would be a network-based Flight Data Recorder ("Black Box "). With the collected position and acceleration data can reconstruct a crash situation very accurately and also the rescue services get a very accurate position message about the accident location. Often one is Accident situation already in a certain, often short period before foreseeable. Then you could the time intervals shortened in which the navigation vectors are transmitted by satellite become.

Fly zones could be controlled even more effectively with this system. Automated can based on the prediction Alarms are issued even before any forbidden zones are reached become. With the system according to the invention can also collisions with the landscape and mountains (controlled flight into terrain) earlier be detected and thus prevented. With a dynamic airplane model, the terrain data and information about The control actions foresee such situations much earlier as with purely linear predictions and height measurements.

With the installed satellite communication system, a set of machine-specific data can be transmitted in addition to the navigation data. The embodiment in 4 shows how such a standardized record could look like. In addition to the aircraft ID and timestamp, the exact aircraft type designation and a serial number are interesting, as well as a machine-specific set of status data, warning messages and finally a digital cryptograph signature for counterfeiting.

In 7 an embodiment for an automated evaluation of machine data is shown. With the collected machine values, a computer simulation can be operated, which models the aircraft and its subsystems in real time. The dynamic system behavior can thus be monitored and possible malfunctions can be detected early by the expert system. Although even the on-board systems of the aircraft itself should recognize or recognize important faults, this would be a great additional help in elaborate ground-based installations, at least in support of them. Much more complex analysis is also possible on large computers. It also relieves the pilot, who does not have much time for difficult technical analyzes during the flight. Experts for each specific type of aircraft might be better able to handle critical situations in a team on the ground. In addition, the message paths are significantly accelerated if the airline already receives automated notifications, such as "increased fuel loss" transmitted. Certainly such a system would also prevent various emergency landings resulting from incorrect calculations of the quantity of fuel, for example in Vienna in July 2000; in this case, the pilot's erroneous calculation of the fuel quantity even led to a crash with total damage. With the proposed ground simulation such a crash landing would have been prevented.

So far became main spoken by air traffic. Likewise, the same system and the same facilities are also of great use in shipping be. Again, you can with such a system threatening accidents in time he knows and prevented. Furthermore, it is automatically recognizable if a ship dangerous Bodies traded or course, for example, on reefs, sandbanks, etc. A shipping company The navigation data can be used simultaneously for your own fleet management use and evaluate the machine data centrally.

modifications compared to the system for the Aviation comment especially in the spatial Model. Here are only two dimensions on the water surface necessary instead of three dimensions in the airspace. The temporal boundary conditions are In addition, less critical, since the vehicle / ships a much lower Have speed as aircraft. In principle, this is the inventive system used in aviation and shipping.

Finally, it will again noted that in the satellite-based system warning of collisions and traffic management - based on a satellite navigation system, a satellite communication system, a computer simulation and an expert system - all vehicles a mode of transport recorded and their routes are simulated. This will be done with help a data transfer of state, change and control data Routes are not estimated linearly but also precalculated nonlinear curves relatively accurately. This allows much more accurate collision warnings. As well can simultaneously Transfer machine data that enable a complex ground-based fault diagnosis.

expert systems can based on simulations automated faulty states and dangerous situations recognize, possibly very much earlier as human observers. Even warnings become so automatic generated in the control centers on the ground relatively quickly and can be comprehensively reacted. The benefits of the system, the a new quality Traffic Management and Collision Prediction offers and both can be used profitably in aviation as well as in shipping is, on the one hand, in an increased security and on the other hand also in economic Benefits by optimizing maintenance and reducing accident costs become.

Claims (5)

Satellite-based system for warning against collisions and traffic management of vehicles, such as aircraft, characterized in that in an aircraft by means of a satellite navigation system ( 41 to 43 ) determined position vectors and other state, change and control vectors via a secured satellite communication system ( 51 to 55 ) to a ground based computer simulation system ( 8th ) including expert system ( 16 ), from which all trajectories are recorded and pre-calculated for a certain period of time. A system according to claim 1, characterized in that in support of the system by additional radar measurements detected new flying objects with identification, position and velocity vector in the computer simulation system ( 8th ) and their position by means of the satellite communication system ( 51 to 55 ) known flying objects is verified. System according to one of claims 1 or 2, characterized in that for the expansion of the system additionally a data set with machine data of the aircraft is transmitted so that on the ground by type-specific computer simulation early error conditions are detected on the aircraft, the airline is forewarned and / or hand instructions are given, System according to one of the preceding claims, characterized characterized in that for the authorized monitoring of airspace injuries or dangerous Zones the airspace simula tion with a digital terrain map and in areas marked therein, System according to one of the preceding claims, characterized in that in crashes, accidents or collisions by means of a network centric flight data recorder (black box) and / or an accident position sensor transmitted navigation data sets and machine data an accident situation is reconstructed in detail and specified the accident location very accurate and automated becomes. 6, system for warning of collisions of vehicles, such as ships, and for the traffic management of a fleet, characterized in that a ship by means of a satellite navigation system ( 41 to 43 ) determined position vectors and other state, change and control vectors via a secured satellite communication system ( 51 to 55 ) to a computer simulation system ( 8th ) including expert system, from which all routes / routes are recorded and pre-calculated for a certain period of time.