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Navigation systems for private aircraft. Navigation systems. Basic navigation parameters in English terminology

AVIATION INSTRUMENTS
instrumentation that helps the pilot fly the aircraft. Depending on their purpose, aircraft on-board instruments are divided into flight and navigation devices, aircraft engine operation monitoring devices and signaling devices. Navigation systems and automatic machines free the pilot from the need to constantly monitor instrument readings. The group of flight and navigation instruments includes speed indicators, altimeters, variometers, attitude indicators, compasses and aircraft position indicators. Instruments that monitor the operation of aircraft engines include tachometers, pressure gauges, thermometers, fuel gauges, etc. In modern on-board instruments, more and more information is displayed on a common indicator. A combined (multifunctional) indicator allows the pilot to cover all the indicators combined in it at a glance. Advances in electronics and computer technology have allowed for greater integration in cockpit instrument panel design and avionics. Fully integrated digital flight control systems and CRT displays give the pilot a better understanding of the aircraft's attitude and position than previously possible.

The CONTROL PANEL of a modern airliner is more spacious and less cluttered than on older airliners. The controls are located directly “under the hand” and “under the foot” of the pilot.


A new type of combined display - projection - gives the pilot the opportunity to project instrument readings onto the windshield of the aircraft, thereby combining them with the external panorama. This display system is used not only on military aircraft, but also on some civil aircraft.

FLIGHT AND NAVIGATION INSTRUMENTS


The combination of flight and navigation instruments provides a description of the condition of the aircraft and the necessary influences on the control elements.
Such instruments include altitude, horizontal position, airspeed, vertical speed and altimeter indicators. For greater ease of use, the devices are grouped in a T-shape. Below we will briefly discuss each of the main devices. The attitude indicator is a gyroscopic device that provides the pilot with a picture of the outside world as a reference coordinate system. The attitude indicator has an artificial horizon line. The airplane symbol changes position relative to this line depending on how the airplane itself changes position relative to the real horizon. In the command attitude indicator, a conventional attitude indicator is combined with a flight control instrument. The command attitude indicator shows the aircraft's attitude, pitch and roll angles, ground speed, speed deviation (true from the "reference" air speed, which is set manually or calculated by the flight control computer) and provides some navigation information. In modern aircraft, the command attitude indicator is part of the flight navigation instrument system, which consists of two pairs of color cathode ray tubes - two CRTs for each pilot. One CRT is the command attitude indicator, and the other is the planning navigation instrument (see below). CRT screens display information about the spatial position and position of the aircraft in all phases of flight.



Planned navigation device. The planned navigation device (PND) shows the course, deviation from the given course, the bearing of the radio navigation station and the distance to this station. PNP is a combined indicator that combines the functions of four indicators - heading indicator, radiomagnetic indicator, bearing and range indicators. An electronic POP with a built-in map indicator provides a color map image indicating the aircraft's true position relative to airports and ground-based radio navigation aids. Flight direction displays, turn calculations and desired flight paths provide the ability to judge the relationship between the aircraft's true position and desired position. This allows the pilot to quickly and accurately adjust the flight path. The pilot can also display prevailing weather conditions on the map.

Airspeed indicator. When an aircraft moves in the atmosphere, the oncoming air flow creates a high-speed pressure in a pitot tube mounted on the fuselage or on the wing. Airspeed is measured by comparing the velocity (dynamic) pressure with the static pressure. Under the influence of the difference between dynamic and static pressures, an elastic membrane bends, to which an arrow is connected, indicating the air speed in kilometers per hour on a scale. The airspeed indicator also shows the evolutionary speed, Mach number and maximum operational speed. A backup airspeed indicator is located on the central panel.
Variometer. A variometer is necessary to maintain a constant rate of ascent or descent. Like an altimeter, a variometer is essentially a barometer. It indicates the rate of change in altitude by measuring static pressure. Electronic variometers are also available. Vertical speed is indicated in meters per minute.
Altimeter. The altimeter determines the altitude above sea level based on the relationship between atmospheric pressure and altitude. This is, in essence, a barometer, calibrated not in pressure units, but in meters. Altimeter data can be represented in a variety of ways - using arrows, combinations of counters, drums and arrows, through electronic devices that receive signals from air pressure sensors. See also BAROMETER.

NAVIGATION SYSTEMS AND AUTOMATICS


Airplanes are equipped with various navigation machines and systems that help the pilot navigate the aircraft along a given route and perform pre-landing maneuvers. Some such systems are completely autonomous; others require radio communication with ground navigation aids.
Electronic navigation systems. There are a number of different electronic air navigation systems. Omnidirectional radio beacons are ground-based radio transmitters with a range of up to 150 km. They typically define airways, provide approach guidance, and serve as reference points for instrument approaches. The direction to the omnidirectional beacon is determined by an automatic on-board direction finder, the output of which is displayed by a bearing indicator arrow. The main international means of radio navigation are VOR omnidirectional azimuthal radio beacons; their range reaches 250 km. Such radio beacons are used to determine the air route and for pre-landing maneuvers. VOR information is displayed on the PNP and rotating arrow indicators. Distance Measuring Equipment (DME) determines the line-of-sight range within approximately 370 km of a ground-based radio beacon. Information is presented in digital form. To work together with VOR beacons, instead of a DME transponder, ground equipment of the TACAN system is usually installed. The composite VORTAC system provides the ability to determine azimuth using the VOR omnidirectional beacon and range using the TACAN ranging channel. An instrument landing system is a beacon system that provides precise guidance to an aircraft during final approach to the runway. Localization landing radio beacons (range of about 2 km) guide the aircraft to the center line of the landing strip; glide path beacons produce a radio beam directed at an angle of about 3° to the landing strip. The landing course and glide path angle are presented on the command attitude indicator and POP. The indices located on the side and bottom of the command attitude indicator show deviations from the glide path angle and the center line of the landing strip. The flight control system presents instrument landing system information via a crosshair on the command attitude indicator. The microwave landing support system is a precise landing guidance system with a range of at least 37 km. It can provide approach along a broken trajectory, along a rectangular “box” or in a straight line (from the course), as well as with an increased glide path angle specified by the pilot. Information is presented in the same way as for an instrument landing system.
see also AIRPORT ; AIR TRAFFIC CONTROL. Omega and Laurent are radio navigation systems that, using a network of ground-based radio beacons, provide a global operating area. Both systems allow flights along any route chosen by the pilot. "Loran" is also used when landing without using precision approach equipment. The command attitude indicator, POP and other instruments show the aircraft's position, route and ground speed, as well as course, distance and estimated time of arrival for selected waypoints.
Inertial systems. The inertial navigation system and inertial reference system are completely autonomous. But both systems can use external navigation tools to correct the location. The first of them detects and records changes in direction and speed using gyroscopes and accelerometers. From the moment the plane takes off, sensors respond to its movements and their signals are converted into position information. In the second, ring laser gyroscopes are used instead of mechanical gyroscopes. A ring laser gyroscope is a triangular ring laser resonator with a laser beam divided into two beams that propagate along a closed path in opposite directions. The angular displacement results in a difference in their frequencies, which is measured and recorded. (The system responds to changes in the acceleration of gravity and to the rotation of the Earth.) Navigation data is sent to the POP, and position data in space is sent to the command artificial horizon. In addition, the data is transferred to the FMS system (see below). see also GYROSCOPE; INERTIAL NAVIGATION. Flight data processing and display system (FMS). The FMS system provides a continuous view of the flight path. It calculates airspeeds, altitudes, ascent and descent points that are most fuel efficient. In this case, the system uses flight plans stored in its memory, but also allows the pilot to change them and enter new ones through the computer display (FMC/CDU). The FMS system generates and displays flight, navigation and operational data; it also issues commands to the autopilot and flight director. In addition, it provides continuous automatic navigation from the moment of takeoff to the moment of landing. FMS data is presented on the control panel, the command attitude indicator and the FMC/CDU computer display.

AIRCRAFT ENGINE OPERATION CONTROL DEVICES


Aircraft engine performance indicators are grouped in the center of the instrument panel. With their help, the pilot controls the operation of the engines, and also (in manual flight control mode) changes their operating parameters. Numerous indicators and controls are required to monitor and control the hydraulic, electrical, fuel and maintenance systems. Indicators and controls, located either on the flight engineer's panel or on the hinged panel, are often located on a mimic diagram corresponding to the location of the actuators. Mnemonic indicators show the position of the landing gear, flaps and slats. The position of ailerons, stabilizers and spoilers may also be indicated.

ALARM DEVICES


In the event of malfunctions in the operation of engines or systems, or incorrect configuration or operating mode of the aircraft, warning, notification or advisory messages are generated for the crew. For this purpose, visual, audible and tactile signaling means are provided. Modern on-board systems can reduce the number of annoying alarms. The priority of the latter is determined by the degree of urgency. Electronic displays display text messages in the order and emphasis appropriate to their importance. Warning messages require immediate corrective action. Notification - require only immediate familiarization, and corrective actions - in the future. Advisory messages contain information important to the crew. Warning and notification messages are usually made in both visual and audio form. Warning alarm systems warn the crew of violations of normal aircraft operating conditions. For example, the stall warning system alerts the crew to such a threat by vibration of both control columns. The Ground Proximity Warning System provides voice warning messages. The wind shear warning system provides a visual warning and a voice message when an aircraft's route encounters a change in wind speed or direction that could cause a sudden decrease in airspeed. In addition, a pitch scale is displayed on the command attitude indicator, which allows the pilot to quickly determine the optimal angle of climb to restore the trajectory.

KEY TRENDS


"Mode S" - the intended data link for air traffic control - allows air traffic controllers to transmit messages to pilots displayed on the aircraft's windshield. The Traffic Collision Alert System (TCAS) is an on-board system that provides information to the crew about required maneuvers. The TCAS system informs the crew about other aircraft appearing nearby. It then issues a warning priority message indicating the maneuvers required to avoid a collision. The Global Positioning System (GPS), a military satellite navigation system that covers the entire globe, is now available to civilian users. By the end of the millennium, the Laurent, Omega, VOR/DME and VORTAC systems were almost completely replaced by satellite systems. The Flight Status Monitor (FSM), an advanced combination of existing notification and warning systems, assists the crew in abnormal flight situations and system failures. The FSM monitor collects data from all on-board systems and issues text instructions to the crew to follow in emergency situations. In addition, he monitors and evaluates the effectiveness of the corrective measures taken.

LITERATURE


Dukhon Yu.I. etc. Handbook on communications and radio engineering support of flights. M., 1979 Bodner V.A. Primary information devices. M., 1981 Vorobiev V.G. Aviation instruments and measuring systems. M., 1981

Collier's Encyclopedia. - Open Society. 2000 .

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A navigation complex is understood as a set of on-board measuring instruments and computers that make it possible to determine the location and speed of an aircraft (vessel) relative to the Earth. None of the existing navigation meters can completely solve these problems, since each of them individually does not provide the necessary accuracy, noise immunity or reliability.

The tasks solved by the navigation system are diverse. Among them, one of the most important is dead reckoning, which provides continuous measurement of the coordinates of an object. The main disadvantage of number systems is the deterioration in the accuracy of determining coordinates with increasing operating time.

Therefore, to obtain the required accuracy, the calculated coordinates must be continuously or periodically adjusted based on information received from radio engineering meters, i.e., complex data processing must be carried out.

The block diagram of a typical aircraft navigation system is shown in Fig. 22.20. The basis of this complex is an inertial navigation system (INS) on a gyro-stabilized platform. It measures both the angular position of the aircraft (roll, pitch, yaw angles and their derivatives) and the acceleration and velocity components. Aircraft speed is also measured using the DISS and the airspeed sensor included in the Air Signal System (ASS). The vertical heading system (CVS) is used as an auxiliary heading meter. Altitude and its rate of change are measured using radio altimeters (RA). The signals from these devices are processed in a computing device that is part of a distributed on-board computing system. As systems for correcting the coordinates of the aircraft location, data from radio engineering systems of short-range RSBN) and long-range (RSDN) navigation (such as Omega, Loran-S or systems using artificial satellites), airborne radars, correlation-extremal systems, as well as data obtained from the output of other meters, such as astronomical landmarks, optical or electron-optical sights.

In navigation systems with a higher degree of equipment integration, feedback links are used (shown in Fig. 22.20 by dotted lines). Due to these connections, correction of the position of the INS gyroplatform, preliminary adjustment of the DISS based on data from the airspeed sensor or INS, installation of sights at the expected location of landmarks, etc. are ensured. Since the systems included in the navigation complex determine navigation parameters in their own coordinate system, in The algorithms of the navigation computing device provide a procedure for recalculating the data of these systems into the main coordinate system in which dead reckoning is carried out.

The navigation complex is an integral part of the flight navigation complex (FNC), which also includes an automatic aircraft control system and a system for indicating and displaying flight navigation information. The PNK is designed for navigation and piloting of the aircraft at all stages of flight. The range of tasks solved by the FNC, in addition to the continuous determination of the coordinates of the aircraft's location, dead reckoning and its correction, includes programming the flight route, calculating and transmitting control signals to the ACS, issuing information to display and indication systems, automatic monitoring of the health of on-board devices and FNC systems, as well as automatic stabilization and control of the aircraft in all flight modes.

Navigation systems of sea vessels have a similar structure. In Fig. 22.21 shows a block diagram of the integrated navigation complex “Data Bridge” of the Norwegian company “Norcontrol”, designed to automate navigation and avoid collisions. Dead reckoning in this complex is carried out according to log and gyrocompass data. The Decca navigation systems (continuous correction in coastal navigation conditions), Omega, Laurent-S, as well as the Transit satellite navigation system are used as position coordinate correction systems.

The on-board computer implements the appropriate algorithms for converting coordinates and complex processing of information from all navigation sensors, and also generates the necessary signals for the automatic control systems for the movement of the vessel and the system for indicating and displaying the situation in the navigation area. The radar image received by the ship's radar is also entered into the display system.

Write down the vector-matrix equation of a linear shaping filter that models the trajectory of a moving object, and draw its block diagram.

How can you describe the maneuvering of moving objects?

In what cases will the measurement equation of an object be linear?

When can you use the results of parameter estimation theory to solve a filtering problem?

By analogy with equations (22.21), (22.22), obtain an equation for estimating the parameters of a quadratic trajectory and draw a block diagram of the corresponding non-recurrent filter.

What is the effect of divergence of estimates in recurrent filters and in what ways can it be prevented?

Using expressions (22.45), (22.46), find the transition matrix of the discrete system, provided that the corresponding continuous system has the matrix

Write down an expression for the correlation matrix of filtering errors for the extended system described by equations (22.52), (22.53).

Specify the main condition under which the integration of two measuring systems is effective.

What is the principle of invariance during integration and how is it implemented when using software processing methods?

Today, navigation technologies are at a level of development that allows them to be used in a wide variety of areas. The range of possible uses of navigation systems is very wide. In world practice, navigation systems have found application not only in such areas as military and civil aviation, but also in shipping, land transport management, and also when performing geodetic work. But regardless of the scope of application, all navigation systems must meet basic requirements:

Integrity

Business continuity

Accuracy of determining the speed of movement of an object, time and location coordinates

Organizational, spatial and temporal accessibility.

In the field of aviation, different navigation systems are used, depending on the purpose and direction in which the aircraft is used. More complete information about various types of aviation can be found on the website. First of all, navigation systems are used in civil aviation, which requires navigation systems to ensure safety and reliability, as well as cost-effectiveness of air traffic. Besides, aviation navigation systems must be global and unified for all stages of flight, in order to reduce the amount of equipment, both on board and at ground points. At the same time, they should also make it possible to clearly determine the course of movement and the distance to the destination and deviation from the given course.

The main tasks of air navigation include:

1. Determination of aircraft navigation elements. In this case, its coordinates, altitude (absolute and relative), flight speed, course of movement and many other parameters are determined.

2. Monitor the path and correct it as necessary

3. Building the optimal route to reach your destination. In this case, the main task of the navigation system is to help you reach your destination in a minimum time with minimum fuel consumption

4. Prompt adjustment of the route during the flight. The need to change the flight mission may arise in the event of a malfunction of the aircraft, in the presence of adverse meteorological phenomena along the route, in order to approach a certain aircraft or, conversely, to avoid a collision with it.

Various technical means are used to determine aircraft navigation systems. Geotechnical means make it possible to determine the flight altitude, both absolute and relative, the location of the aircraft and its course of movement. They are represented by various technical means: altimeters, optical sights, various compasses, etc. Radio technology makes it possible to determine the ground speed, true flight altitude and location of the aircraft by measuring various indicators of the electromagnetic field using radio signals.

From the point of view of the authors of the site, astronomical navigation aids can also determine the location of the aircraft and its course of movement. For these purposes, astronomical compasses, astro-orientators and other equipment are used. The task of lighting navigation systems (light beacons) is to ensure the landing of aircraft at night or in difficult meteorological conditions using easier orientation in space. And finally, there are complex navigation systems that are capable of providing automatic flight along the entire route. In this case, it is even possible to make an approach without visibility of the landing surface. Such systems are also called autopilot.

General description of the aircraft navigation computer system

The computational aircraft navigation system (FMS) is designed to solve problems of 3-dimensional navigation of an aircraft along a route, in the airport area, as well as performing non-precision approaches.

The Flight Management System (FMS) provides:

  • issuing control signals to the automatic control system for automatic flight control along a given route;
  • solving problems of navigation along a given flight route, performing non-precision approaches to landing in vertical navigation mode;
  • automatic and manual frequency adjustment of on-board radio navigation systems and instrumental landing systems;
  • control of modes and range of the T2CAS aircraft collision avoidance system;
  • manual configuration of on-board VHF and HF radio communication systems;
  • control of the code function in onboard transponders of the ATM system;
  • introduction (modification) of an alternate airport.

The function of the FMS is to transmit navigation information in real time by displaying the route selected (created) by the crew, as well as standard takeoff and landing procedures selected from a database. FMS calculates horizontal and vertical flight profile data along the route.

To perform navigation functions, FMS interacts with the following systems:

  • inertial navigation system IRS (3 sets);
  • global navigation satellite system (GNSS) (2 sets);
  • air signal system (ADS) (3 sets);
  • HF radio station (2 sets);
  • VHF radio station (3 units);
  • ATC transponder (XPDR) (2 units);
  • range measurement system (DME) (2 sets);
  • omnidirectional and marker radio beacons (VOR) system (2 sets);
  • instrumental landing system (ILS) (2 sets);
  • automatic radio compass (ADF) system;
  • Flight Warning System (FWS);
  • mid-air collision avoidance system (T2CAS);
  • electronic display system (CDS);
  • automatic control system (AFCS).

The front panel of the FMS has a multifunctional control and display unit (MCDU).

Figure 1: MCDU Front Panel Description

The FMS transmits control signals to the autopilot (AFCS) to control the aircraft:

  • in the horizontal plane for navigation on the route and in the airport area (horizontal navigation LNAV);
  • in the vertical plane for takeoff, climb, flight at cruising speed, descent, approach and go-around.

The FMS transmits the aircraft's location, flight route, information about the current navigation mode, etc. to the CDS. This data is displayed on the navigation display (ND) or primary display (PFD).

The crew uses the flight control console (FCP) to select flight modes and the MCDU included in the FMS to enter the flight plan and other flight data. The crew uses a multifunctional control and display panel to enter and edit data using the keyboard.

The FMS is the sole means of controlling the Air Traffic Control (ATC) transponders and the Airborne Collision Avoidance Subsystem (TCAS). FMS is the main means of controlling radio navigation systems and a backup means of configuring radio communication equipment.

FMS has the following databases:

  • navigation database;
  • special database (company routes);
  • user database;
  • magnetic declination database;
  • aircraft characteristics database.

The databases and configuration file listed above are updated when performing FMS maintenance procedures through the MAT (Maintenance Systems Terminal) used as an ARINC 615-3 data loader. Software updates are also performed via MAT.

FMS performs the following functions:

  • Flight plan development;
  • Determining your current location;
  • Predicting the flight path during descent;
  • Horizontal navigation;
  • Vertical navigation during the landing phase;
  • Setting up radio communication equipment;
  • ATC/TCAS radio control;
  • Control of radio navigation aids.

Functional description of FMS

The RRJ family aircraft are equipped with two CMA-9000s, which can operate in both independent and synchronous modes. When operating in synchronous mode, the CMA-9000 exchanges the results of the corresponding navigation calculations. In independent mode, each CMA-9000 uses the results of its own navigation calculations.

Typically, CMA-9000s operate in synchronized mode, but will switch to independent mode if the following conditions occur when two CMA-9000s are operating:

  • different user databases;
  • different software versions;
  • different navigation databases;
  • communication error of one of the CMA-9000 when making a connection;
  • different flight phases of more than 5 seconds;
  • various navigation modes for more than 10 seconds.

When operating in independent mode, the CMA-9000 notifies the crew of changes in operating modes. In this case, the corresponding IND indication appears on the MCDU, and a corresponding yellow message appears on the MCDU screen. If one of the CMA-9000s fails in flight, the other allows the flight to be completed without loss of functionality.

Flight plan development

FMS supports the pilot by developing a complete flight plan from takeoff to landing, including navigation equipment, waypoints, airports, airways and standard procedures for takeoff (SID), landing (STAR), approach (APPR), etc. d. The flight plan is created by the crew by waypoints and air routes using the MCDU display or by downloading airline routes from the appropriate database.

The user's database can include up to 400 different flight plans (aviation company routes) and up to 4000 intermediate route points. The flight plan can include no more than 199 intermediate route points. The FMS can process a user database of up to 1800 different waypoints.

3 flight plans can be created in FMS: one active (RTE1) and two inactive (RTE2 and RTE 3). The crew may make changes to the current flight plan. When a flight plan is changed, a temporary flight plan is created. The modified flight plan becomes active when the EXEC button is pressed and can be canceled when the CANCEL button is pressed. Canceling the entry of an inactive plan does not change the currently active plan (RTE1).

The crew has the ability to create a custom navigation point so that it can later be selected from memory or used in the event of data loss. The user database can store up to 10 user flight plans and up to 500 waypoints along the user's route.

The crew has the ability to create temporary waypoints located on flight plan sections at the intersection of a radial line, beam or radius from a selected location on the FIX INFO page. From the entered FIX, no more than two radial lines/radii and no more than one traverse can be created. CMA-9000 calculates preliminary data (estimated time of arrival (ETA) and flight distance (DTG)) taking into account the flight profile, the specified altitude and speed of the flight and the wind parameters entered by the crew on the route.

The aircraft crew uses the CMA-9000 to enter data required for takeoff and en route flight (decision speed (V1), nose gear rise rate (VR), safe takeoff speed (V2), cruise altitude (CRZ), takeoff aircraft weight (TOGW), etc.), which are used to predict and calculate flight characteristics. During flight, the CMA-9000 is used to input approach data (temperature, wind, expected landing configuration, etc.). In synchronous mode, all data entered into one CMA-9000 is transferred to the other CMA-9000 using the clock bus. The CMA-9000 provides manual entry of aircraft ground position data for IRS exhibition.

The following navigation data is available to the pilot:

  • the height of the destination airport runway;
  • transition altitude and transition level transmitted to the CDS for reflection on the PFD;
  • ILS localizer heading transmitted to AFCS;
  • departure airport runway heading transmitted to AFCS.

The FMS transmits to the CDS a flight plan corresponding to the scale (from 5 to 640 nautical miles) and type (ARC, ROSE or PLAN) of display selected by the crew.

Multi-mode navigation

To determine the location of the aircraft, both CMA-9000s are connected by interfaces with navigation systems. Navigation systems—IRS, GPS, VOR, and DME—provide navigation information to the FMS to determine the aircraft's location. The CMA-9000 continuously calculates the aircraft's position based on information received from GPS (DME/DME, VOR/DME, or INS) and displays the active dead reckoning mode on the displays. The FMS manages the reference navigation performance (RNP) according to the flight phase. When the current ANP exceeds the specified RNP, an alarm is issued to the crew on the MCDU.

The navigation function includes the following parameters, which are calculated or received directly from sensors:

  • current position of the aircraft (PPOS);
  • ground speed (GS);
  • track angle (TK);
  • current wind (direction and speed);
  • drift angle (DA);
  • lateral deviation distance (XTK);
  • track angle error (TKE);
  • specified route track angle (DTK) or heading;
  • current navigation accuracy (ANP);
  • specified navigation accuracy (RNP);
  • stagnation temperature (SAT);
  • aircraft airspeed (CAS);
  • true aircraft speed (TAS);
  • inertial vertical speed;
  • heading (HDG), magnetic or true.

In the main operating mode, latitude and longitude data come directly from the GPS sensors of the GNSS Multi-Mode Receivers (MMR). The location calculation is performed in accordance with the World Geodetic Coordinate System WGS-84.

Priorities for using navigation modes:

  1. GPS navigation mode;
  2. DME/DME navigation mode in case of failures, loss of GPS signals and loss of RAIM;
  3. VOR/DME navigation mode in case of failures and loss of GPS and DME/DME signals;
  4. INERTIAL navigation mode in case of failures and loss of GPS, DME/DME and VOR/DME signals.

Navigation modes

GPS navigation: GPS determines the aircraft's immediate position, ground speed, ground angle, North-South speed, East-West speed and vertical speed. To ensure the completeness of the Autonomous Integrity Monitoring (RAIM) function, the aircraft crew can deselect the mode of GPS or other unreliable navigation aid.

DME/DME navigation: The FMS calculates the aircraft's position using the third channel of DME receivers. If the location of DME stations is contained in the navigation database, the FMS determines the aircraft's position using 3 DME stations. The time-based change in position allows the ground speed and heading angle to be calculated.

VOR/DME navigation: The FMS uses the VOR station and its associated DME to determine the relative course and distance to the station. The FMS determines the aircraft's position based on this information and takes into account changes in position over time to determine ground speed and heading angle.

Inertial navigation INERTIAL: The FMS determines the weighted average between the three IRSs. When the GPS navigation mode (DME/DME or VOR/DME) is in effect, the FMS calculates a position error vector between the IRS-calculated position and the current position.

During inertial navigation, the FMS adjusts the location in its memory based on the last offset vector calculation to ensure a smooth transition from GPS mode (DME/DME or VOR/DME) to inertial navigation mode. In the event of an IRS sensor failure, the FMS calculates a dual mixed INS location between the two remaining IRS sensors. If the IRS sensor fails again, the FMS uses the remaining IRS sensor to calculate the INS position.

Dead reckoning navigation DR: The FMS uses the last determined position data, TAS (true aircraft speed) from the ADC, the entered heading, and forecast wind conditions to calculate the aircraft's position. The aircraft crew can manually enter data on the current location, track angle, ground speed, wind speed and direction.

Trajectory prediction

The FMS predicts the vertical flight profile using true and predicted navigation data. FMS does not calculate forecasts for an inactive route and does not calculate a vertical profile.

The trajectory prediction function calculates the following parameters for pseudo-intermediate route points: the end of climb point (T/C), the start point of descent (T/D) and the end of descent (E/D).

The following parameters are predicted for each intermediate point of the route of the current flight plan:

  • ETA: estimated time of arrival;
  • ETE: planned flight time;
  • DTG: flight distance;
  • cruising altitude.

In addition, ETA and DTG are calculated for entry points to waypoints.

The trajectory prediction function calculates the predicted landing weight and alerts the aircraft crew if additional fuel is required to complete the flight plan.

The trajectory prediction function calculates fuel and distance for takeoff, climb, cruise, and descent based on data contained in the performance database (PDB).

During the approach data calculation phase, the FMS calculates the approach speed based on the landing wind speed data and the predicted speed Vls, which are issued from the PDB, taking into account the expected landing configuration and landing weight.

The trajectory prediction function outputs messages to the MCDU in the event of an incorrect climb. Also, during descent and landing in vertical navigation mode, the FMS transmits the first altitude value to the CDS for reflection on the PFD indicating whether it should be maintained. Additionally, when a Required Time to Land (RTA) is entered at any intermediate descent point, the trajectory prediction function updates the ETA to the RTA and alerts the aircraft crew if the time does not match.

The FMS sends data for display on the navigation display using the ARINC 702A protocol and according to the map display function, the selected range and the selected map mode.

Horizontal and vertical navigation

This function provides horizontal and vertical navigation in conjunction with the autopilot to execute horizontal and vertical flight plans.

Horizontal LNAV navigation

The LNAV function includes the calculation of roll commands necessary to ensure flight in the horizontal plane, calculates and transmits the lateral deviation (XTK) to the PFD and ND display.

FMS manages:

  1. In the horizontal plane on the route and in the airport area when performing:
      • flight along a given sequence of intermediate route points (IRP);
      • flight “Direct on” (DIRECT-TO) trajectory, waypoint or radio navigation aid;
      • turning with PPM flight or with advance;
      • initialization of the missed approach procedure (GO AROUND).
  2. When entering a holding area and when flying in a holding area, the FMS performs:
      • constructing and displaying the geometry of the holding area (HOLD);
      • entrance to the waiting area;
      • flight in the holding area;
      • leaving the waiting area.
  3. In the horizontal plane along the route:
      • calculation of the time of flight over the waypoint and arrival at the final point of the route;
      • parallel route to the left or right of the current flight plan course (OFFSET).

In LNAV mode, FMS can perform:

  • changing the active stage from the FLY-BY type waypoint to the next one when crossing the bisector of the angle between the path lines of these stages. After crossing, the new stage is activated and becomes the first;
  • changing the active stage from a waypoint (WPT) of the FLY-OVER type to the next one, when passing the ACT WPT or stopping its traverse;
  • guidance to the “Direct-to” point (DIRECT-TO) to ensure a turn to the course of the selected (manually entered) WPT;
  • navigation and guidance on the course of entering the holding area “Direct to a fixed point” (DIRECT TO FIX);

FMS ensures safe aircraft navigation in the B-RNAV area navigation system along Russian routes with an accuracy of ±5 km and ±10 km and in the airport area in the P-RNAV precision area navigation system with an accuracy of ±1.85 km.

The horizontal navigation function provides the CDS with navigation parameters that are reflected on the PFD or ND.

The horizontal navigation feature provides an approach using GPS non-precision approach aids.

Entering (modifying) an alternate airport

The Flight Management System (FMS) enters alternate airports (RTE2 and RTE3), which are constructed as inactive routes.

A diversion to an alternate airport can be planned using a modified active route:

  • Flight from active flight plan RTE1 to alternate airport RTE2;
  • Flight from active flight plan RTE1 to RTE3 with option VIA. The VIA point is determined through RTE1 of the take-off airport;
  • Flight from the active flight plan to the alternate airport RTE3 with the VIA option. The VIA point is determined through the waypoint (WPT) at the destination airport RTE1 (APP, MAP) for arrival at the destination airport RTE3.

Configuring radio communication equipment using FMS

The radio communications equipment configuration function ensures the operation of three different groups of systems: navigation radios, radio communications equipment, and ATC/TCAS radios.

Setting up navigation radios

Navigation radios available on RRJ family aircraft: DME1, DME2, ADF1, ADF2 (optional), VOR1, VOR2, MMR1, MMR2 (ILS, GPS).

FMS is the main means of configuring navigation radios. All setup-related data is transmitted to the radios via the Radio Management Panel (RMP). When you press the NAV button on the RMP, tuning from the FMS is locked and all radios are tuned from the RMP remotes.

The navigation radio tuning function automatically configures VOR, DME and ILS to match the flight plan.

The radio control function transmits to the CDS for reflection on the ND the tuning mode of the selected VOR and ILS station, which can be automatic, manual from the MCDU or from the RMP console.

Setting up radio communication equipment

Radio communications equipment available on RRJ family aircraft: VHF1, VHF2, VHF3, HF1 (optional), HF2 (optional).

The radio communication equipment configuration function configures communication radio stations. The main means of configuring radio communication equipment is the RMP remote control. Only after both RMPs have failed or are turned off is radio tuning done using the FMS.

FMS connects to radio stations via RMP remote control. The radio configuration function receives a code value from the data concentrator, which is activated in the event of failure or shutdown of two RMPs. When entering a code value, the radio configuration function sets the “com port select” mode for RMP and allows you to configure radio communication with the MCDU. Otherwise, configuration from FMS is prohibited. The RMP does not connect directly to high frequency radios. Configuration is done through the avionics cabinet data concentrator to allow protocol adaptation. The VHF3 radio does not have the ability to tune from FMS, only from RMP remotes.

ATC/TCAS radio control (a subsystem that is part of the T2CAS equipment)

The selection of TCAS modes and range is carried out from the FMS. The aircraft crew can select three modes on the MCDU: STANDBY - standby, TA ONLY - only TA, and TA / RA (proximity mode / conflict resolution mode) in the following altitude range: NORMAL - normal, ABOVE - “above” and BELOW - "under".

In addition, the aircraft crew can perform the following actions to control ATC transponders:

  • Selecting an active transponder;
  • ATC mode selection (STANDBY or ON);
  • Entering XPDR code;
  • Activation of the “FLASH” function (with MCDU or by pressing the ATC IDENT button on the central console);
  • Controls the altitude transfer function (ON or OFF).

In addition, when the panic button in the cab is activated, the radio control function activates the emergency code 7500 ATC.

The radio control function verifies the readiness of ATC transponders by comparing the ATC_ACTIVE feedback with the start/standby command sent to each ATC transponder. If a malfunction of the ATC transponder is detected, a text message is generated on the display.

MCDU calculator function

The MCDU function provides the aircraft crew with a calculator and converter to perform the following conversions:

  • meters ↔ feet;
  • kilometers ↔ NM;
  • °C ↔ °F;
  • US gallons ↔ liters;
  • kilograms ↔ liters;
  • kilograms ↔ US gallons;
  • kilograms ↔ pounds;
  • Kts ↔ miles/hour;
  • Kts ↔ kilometers/hour;
  • kilometers/hour ↔ meters/sec;
  • feet/min ↔ meters/sec.

FMS equipment

The FMS consists of two SMA-9000 blocks, which include a computer and an MCDU.

Specifications

  • Weight: 8.5lbs (3.86kg);
  • Power supply: 28V DC;
  • Energy consumption: 45W without heating and 75W with heating (start with heating at a temperature less than 5° C);
  • Passive cooling without forced air supply;
  • MTBF: 9500 flight hours;
  • Electrical Connector: A 20FJ35AN connector is located on the rear panel of the FMS.

CMA-9000 includes:

  • Databases developed in accordance with DO-200A;
  • Software developed in accordance with DO-178B Level C.
  • Complex hardware components designed in accordance with DO-254 Level B.

FMS interaction interfaces

Figure 2. Interface of FMS input signals with avionics systems and aircraft systems

Figure 3. Interface of FMS output signals to avionics and other aircraft systems

Failsafe

Avionics system functional hazard assessment (SSJ 100 aircraft AVS FHA (RRJ0000-RP-121-109, Rev. F) defines the hazard degree of FMS functional failure situations as a “Complex situation”. The probability of occurrence of certain types of failure situations considered in RRJ0000-RP- 121-109 rev.F, must meet the following requirements:

  • At all stages of flight, the probability of an unindicated failure of the CMA-9000 does not exceed 1.0 E-05.
  • At all stages of flight, the likelihood of misleading navigation data from the CMA-9000 (horizontal or vertical navigation) being output to both ND navigation displays does not exceed 1.0 E-05.
  • At all stages of flight, the probability of issuing a false control signal from the CMA-9000 to the autopilot does not exceed 1.0 E-05.

RRJ Avionics System Safety Assessment (J44474AD, I.R.: 02) of the RRJ Avionics Suite (Part number B31016HA02) as installed in the Russian Regional Jet (RRJ) 95B/LR aircraft ) shows that the probability of occurrence of the above failure situations is:

  • unsignaled failure (loss) of navigation information from FMS - 1.1E-08 per average flight hour;
  • delivery of misleading navigation data from the CMA-9000 (horizontal or vertical navigation) to both navigation displays ND – 1.2E-09 per average flight hour;
  • issuance of a false control signal from the CMA-9000 for the autopilot - 2.0E-06 per average flight hour.

The obtained (J44474AD, I.R.: 02) probabilities of failure situations comply with the fail safety requirements (RRJ0000-RP-121-109 rev. F).

In accordance with the requirements for each CMA-9000, the probability of issuing false data according to ARINC 429 does not exceed 3.0E-06.

FMS hardware and software development level (DAL) according to DO-178 is level C.

Degraded mode

Both CMA-9000s are connected in dual synchronized mode. The failure of just one does not mean a decrease in the functionality of the FMS. The crew can manually reconfigure the displays to reflect data from the opposing CMA-9000 using the Configuration Control Panel (RCP).

In the event of a failure of the range and/or map mode select input signal from the FCP, the FMS transmits a default map data of 40 nm/ROSE.

If navigation sensors fail, the FMS provides DR mode based on air traffic and wind data to calculate the aircraft's position. The FMS notifies the aircraft crew about navigation in DR mode. In DR mode, FMS provides the ability to enter current location, ground speed, route, wind direction and magnitude. The FMS must accept the entered rate.

When working together, the FMS exchanges with the opposite CMA-9000 in order to ensure synchronous operation.

When operating in independent mode or in the event of a data bus failure between two FMSs, it is possible to change the master-slave data link from both MCDUs.

Major engineer O. Nikolsky

The targeting and navigation system installed on F-16 fighters, judging by foreign press reports, is designed to provide aircraft navigation day and night in various meteorological conditions, detect targets and measure their parameters, use airborne weapons against air and ground targets, and automatically monitor the performance of equipment units and solving some other special problems. It is built on the basis of a central computer and includes: AN/APG-66 radar station, type 666 sighting system, SKN-2416 inertial navigation system, aerodynamic parameters computer and control panel. The interrogator of the short-range navigation radio system TAKAN AN/ARN-118 and the radio altimeter AN/APN-194 are used as auxiliary navigation devices. The information necessary for the pilot is displayed on indicators located on the front instrument panel and against the background of the cockpit windshield. The interaction of individual blocks of the system is carried out through a signal transmission network with multiplexing, for which these blocks have corresponding terminal devices.
The central computer M362 (“Mazhik 362F”) has software control and is built on microcircuits of an average level of integration. The machine's memory capacity is 32 thousand 16- or 32-bit words, the operating cycle time is 1.2 μs, its weight is 9 kg, the housing size is 500X125X195 mm. It uses the JOVIAL/LZV language. The computer is interfaced with an air parameters computer, various sensors and indicators of the F-16 fighter. Its main function is to integrate and convert data coming from various sensors of the sighting and navigation system. The machine stores information about malfunctions in the main blocks of the system that occur during the flight. After the flight, this information can be retrieved from the storage device and displayed on an indicator located on the aircraft instrument panel.
Multifunctional pulse-Doppler radar AN/APG-66 is designed for all-weather search, detection, auto-tracking, as well as measuring the parameters of air targets at ranges up to 45 km and range and closing speed with visually visible ground targets.
The station has the following operating modes: search for air targets, their automatic tracking, close air combat, viewing the earth's (water) surface with a regular beam, viewing the earth's (water) surface with a pointed (Doppler narrowing) beam, storing an image of the earth's surface, accurate measurement of the range to visually visible ground targets and navigation (using a beacon). The antenna device, which is a flat slot phased antenna array, provides an azimuth viewing area of ​​more than 120°. In this case, automatic scanning of the antenna beam in sectors of 20, 60 and 120° is allowed. In terms of elevation angle, visibility is possible within 120°, and in automatic mode the zone narrows to 3, 6 or 12° (at the discretion of the pilot).
The foreign press notes that in the process of creating this radar, in contrast to the developments of previous stations, the following were used: a new method of reducing side lobes due to a waveguide-slot phased array antenna, as a result of which there was no need for a compensation channel; modular design principle; methods for calculating the angular velocity of the line of sight using the station's computer (instead of the usual measurement method using gyroscopes); electric motor for driving the antenna; The output stage of the transmitter contains a traveling wave tube with air cooling rather than the usual liquid cooling.
When detecting air targets flying at an altitude, the station operates in pulse mode, and low-flying ones - in pulse-Doppler mode. In both cases, the selected target is captured manually by the pilot. To conduct close air combat, a viewing sector of 20X20° is usually set (values ​​of 10X10° or 40X40° are also possible), and the target closest to the fighter is searched for and automatically captured, starting from a range of 9 km. In addition, the pilot can acquire any other target manually, and then it is tracked automatically in pulse-Doppler mode. The measured coordinates and speed of approach to the target are sent to the central computer to carry out calculations for the use of the selected weapon.
In the "air-to-surface" mode, the slant ranges to visually visible ground targets and the speed of approach to them are accurately measured, with the subsequent transfer of this data to the central computer. Given the known geographic coordinates of the targets, the pilot can enter them into the computer storage device in order to display on the indicator the area of ​​the terrain corresponding to the position of the target. To obtain detailed terrain mapping, the radar is switched to a sharpened beam survey mode, in which the resolution of angular coordinates in sectors from + 15 to + 45° is improved by more than 4 times due to narrowing the antenna beam using special processing of the Doppler components of the signals reflected from various terrain areas within this beam. To increase secrecy, a mode for storing the image of the earth's surface is provided, in which the radar transmitter is turned off, and the image of the terrain received before it was turned off is stored on the indicator. The aircraft's position is indicated by a special marker controlled by the aircraft's inertial system.
According to foreign press reports, the station can also detect surface targets: when the sea state is up to 5 points, the pulse mode is used, and above it, the pulse-Doppler mode is used.
The Type 666 sighting system displays flight and navigation information and generates data necessary for the visual use of weapons. It includes: an indicator that displays data against the background of the windshield with a 127 mm lens; a computer (memory capacity 16 thousand words), which displays symbols and marks on the indicator for the use of weapons in the “air-to-air” and “air-to-surface” modes; a control panel that allows you to select operating modes, adjust the brightness of symbols on the indicator and set the target’s wingspan; an electromechanical device with a gyro sensor for measuring the angular velocities of the line of sight. The computer calculates the flight path of a projectile when firing from a cannon at a pre-emptive point, the permitted launch zones for the Sidewinder missile launcher and the point of impact when bombing, launching unguided missiles and firing from a cannon at ground targets.
The principle of operation of the sight is based on calculating the flight path of a projectile, taking into account data on the heading, pitch and roll of the aircraft received from the inertial navigation system, as well as the influence of gravity, aerodynamic drag and the angle of attack of the projectile. The resulting trajectory in the form of a luminous line is projected onto an indicator with range marks in the form of small transverse lines, the length of which is equivalent to the wingspan of an enemy aircraft at a certain distance, which allows the pilot to visually assess the range. It is believed that in this case there is no need to make complex calculations taking into account the maneuvering of the target to calculate the lead angle. The pilot must anticipate the possible maneuver of the target and pilot the aircraft in such a way that it falls on the calculated trajectory at the moment the cannon fire begins.
In the case of automatic tracking of a target using radar, the sight receives data on the range to it and a reticle and a central mark appear on the indicator, superimposed on the calculated trajectory. The pilot continues to fly the aircraft as before, but uses the grid to determine exactly which part of the trajectory should be superimposed on the target. Maneuvering in azimuth, he must keep the target on the trajectory and open fire at the moment of alignment. Since the firing capabilities of modern aircraft in maneuverable air combat are very limited, to increase the probability of a hit, an F-16 fighter pilot fires at a lead point. The pilot's skill is determined by his skills to keep the target on the calculated trajectory between the corresponding range marks at the moment the shooting begins. Getting the sight ready for use is done almost instantly. The disadvantages of the sight include the inability of foreign experts to operate at night and in fog, as well as a significant reduction in range during rain and in the presence of near-Earth haze.
The inertial navigation system (INS) installed on board is the basis for navigation calculations. It allows dead reckoning with an accuracy of 1.85 km per 1 hour of flight, and measures the heading, roll, pitch, ground speed and vertical acceleration of the aircraft. In addition, it can be used to determine the bearing and range to several pre-selected targets or route points. There are two ways to align the system before a flight: normal (lasting 15-25 minutes) and accelerated (3-5 minutes). In the latter case, the error in measuring the aircraft's location increases to 5.5 km per 1 hour of flight.
The TAKAN short-range radio navigation system, the interrogator of which is installed on board the fighter, is used to correct the INS due to more accurate location determination at distances not exceeding 550 km from the ground station. It allows you to measure range and determine location with an accuracy of 50-200 m, independent of flight time, and azimuth with an accuracy of 1°. In addition, the system provides determination of distances between aircraft when flying in formation. Its operating frequency range (960 - 1215 MHz) is divided into 252 channels, the time spent on measurement is 3 s.
According to American experts, the targeting and navigation system installed on the F-16 does not fully ensure the ability to perform the tasks that the US Air Force command sets for modern fighters of this class. Therefore, the system is currently being modernized as part of the program for phased improvement of the fighter. At the same time, it is planned to significantly improve the capabilities of the on-board radar and improve the equipment of the fighter cabin in order to ensure the possibility of using new all-weather AMRAAM missiles with a radar homing head, as well as new ammunition for hitting small-sized ground targets. In addition, the possibility of installing additional on-board equipment for the NAVSTAR satellite navigation system, the integrated tactical information distribution system GI-TIDS, as well as the LANTIRN sighting and navigation device is being considered.
Radar modernization plans provide, in particular, for increasing the operating range by increasing the radiation power while maintaining the size of the transmitter and introducing several additional operating modes, including: high pulse repetition rate, tracking of air targets on the pass, 64-fold Doppler beam narrowing, indication and tracking of low-contrast ground moving targets, ensuring compliance with the terrain when flying at low and extremely low altitudes. This is expected to be achieved through the use of a more powerful traveling wave lamp in the transmitter, operating at high, low and medium pulse repetition frequencies, the installation of a special programmable processor with increased speed and memory capacity, and the development of new software tools.
In the process of upgrading the cabin equipment, it is planned to install an indicator with diffraction (holographic) optics (Fig. 1), the field of view of which is 2.5 times larger than the existing one, which should significantly improve the conditions for detecting small ground targets when flying at low altitudes at night with using the LANTIRN device and provide indication of IR images of the terrain and target designation symbols when flying in terrain following mode.
The installation of equipment for the NAVSTAR and JITIDS systems, as the foreign press indicates, will significantly increase the capabilities of navigation and target designation, since the accuracy of determining the location of the aircraft will reach 10 m, regardless of flight time, altitude and route point, and the detection range of air and surface targets when using the data from the AWACS system will be several hundred kilometers.
The LANTIRN sighting and navigation device, according to foreign experts, will provide detection, identification and automatic tracking of small moving ground targets day and night, in conditions of near-Earth haze and light fog at a distance of up to 5 km, as well as navigation when following the terrain at small and extremely small heights (30-60 m). The device’s equipment is planned to be placed in two hanging containers. It is expected to include an IR forward-looking system, a laser target designator, a small-sized terrain following radar and a computing device. The IR system will have two sensors: with a wide field of view for obtaining an image of the terrain on an indicator with target designation symbols and following the terrain, and with a narrow field of view for detection, identification and automatic tracking of small-sized ground targets. The most difficult is the development of a signal processing device that will automatically detect potential targets and classify them by type in real time.
The modernization of the F-16 fighter's targeting and navigation system is expected to be completed in the mid-80s. As a result, according to American experts, the combat capabilities of the aircraft should increase when conducting maneuverable air battles and attacks on ground-based small moving and stationary targets.
In particular, the accuracy of aircraft navigation will increase both day and night in various meteorological conditions, the capabilities of on-board equipment to search and detect air and ground targets, the accuracy of determining their coordinates and other parameters, as well as the use of weapons will increase. At the same time, automation of flight and weapon control processes will allow the pilot to pay more attention to monitoring the tactical situation.