4.Automatic control of the airplane during landing 4.1. Means of providing landing

Currently, the most widely used radio system tasks approach path type SP-50 (ILS), PRMG-4, etc. In these systems, the approach path is the line of intersection of the planes of the course and glide path to reduce generated foreign exchange (MRC) and the glide path (RM), beacons, respectively. This line represents the beam. Deviation of the aircraft from the board of the beam are determined by foreign exchange (PKK), and the glide path (HF) radios. Thus, to a range of special equipment to ensure planting include: • ground track, glide slope and localizer RM; • ground marker, joined at the location on the far (DPRS) and near (BPRS) NDB. Marker used to indicate the time of their flight; • board of course and glide slope receivers PKK fracturing; • on-board information systems: low-altitude radar altimeter, compass system, the attitude indicator, automatic control system and the system of director of management. CRM and SRM give signals proportional to the angular deviation of the aircraft from equisignal zones in the polar coordinate system with the poles, combined with the location of the corresponding beacon. ACS based on the statistics and realized it carries stabilizing control laws of the aircraft relative equisignal zones CRM and SRM.

The layout of ground system SP-50 is shown in Fig.

Functional diagram avionics instrument landing system is shown in Fig. Crucial role in the management of computer plays trajectory control (WTU), forming setpoint signal pitch and roll angles (overloading), depending on the angular deviation of the aircraft from equisignal zones and .

4.2. Control of the airplane during landing

Planting process can be divided into the following stages: • return the aircraft at the aerodrome; • preplant maneuvering in the terminal area; • approach (preplant maneuver within range of CRM and RM); • proper fit (alignment steps and landings). Return aircraft preplant maneuvering and approach can be performed in an automatic, semi-automatic (-director) or manually. Proper fit, as a rule, in the manual mode. Control of the aircraft to return to the stage of TMA preplant and maneuvering (mode "Return")

The objective of the aircraft in the "Return" is the conclusion of its air space to a point relative to the aerodrome in such a way that it lies on the extension of the runway at a height and distance. Enabling can be either automatic (after the passage of the last MRP) and manually (by pressing a button - light return). In the "Return" ACS provides direction and maintaining the descent path, specified equipment RSBN. Maneuver the aircraft is in the horizontal and vertical planes. A rectangular coordinate system associated with the aerodrome landing. Control in the horizontal plane. Process of going to the airport landing includes generally three stages.

At the first stage, the output of aircraft in the terminal area to the line defined by the range of 200 ... 250 km to the beacon RSBN. CND and ACS also function as a cross-country flight, just as the MRP is programmed RSBN airfield. Control of the airplane, as a rule, foreign exchange method. Given course is formed depending on the distance to the airport landing and the direction of approach. The second stage begins when the turn of the airfield area. In occurs automatically if serviceability airborne and ground equipment systems RSBN. In contrast to the first stage at this stage is the calculation of the true course set to return to the set point. As specified points are conditional points C2 and C3 (third turn point) and the point C1 (point fourth turn), located in a certain way with respect to the aerodrome. Feature functioning NCP at this and subsequent stages of planting is to use the Cartesian coordinate system , related to airport landing and starting at the center of the runway.

Point C1 is given by the point in the case, if the plane at the turn of the airfield area was in quadrants I and II (exchange rate differed from aircraft landing at least 900). From the measured azimuth and slant range to ground beacon calculated the coordinates of the location of the aircraft ( , ). The current coordinates are used to determine the true rate specified airplane flight and distance to it according to the expression

; ,

where, - programmed tc airport landing, ( , ) – coordinates of the target.

If the output at the point where the third turn (the plane at the turn of the zone is in quadrant III or IV), then the distance to it, equal to the radius of rotation (4 km), there are redirected to a point of the fourth turn. Control of the aircraft at this stage is also carried by foreign exchange. The third stage begins at the intersection of 5,5 - km corridor relative to the runway. From this point on the given course is formed using conventional fixed point, which is moving along the runway at a distance of 2.5 km from the projection of the plane on the runway axis. When such control is a smooth transition to the runway axis.

At the entrance to the plane in the area 1.5 km by lateral deviation from the runway RSBN automatically switch to receive signals and timing of MRC, while issuing a command to a one-time transfer of ACS to "Landing". Thus, the construction of the trajectory maneuver in the horizontal plane is characteristic of course the output method to a given point. The parameters of the given points, and control signals are provided to certain algorithms used in calculators navigation system.

Control in the vertical plane. The distance from the aircraft to the appropriate set point program formed a trajectory in the vertical plane. The trajectory is a broken line consisting of three straight sections of the flight at a cruising altitude of 10.5 km reduce land with a slope of 60, called Penetration clouds. In this part of the specified height is formed depending on the distance to the zone preplant maneuver by the formula

, where - distance to a point determined by the expression; =16 km for point C1 and 8 km - for points C2 and C3;

at an altitude maneuver preplant = 630 m.

ACS provides a longitudinal channel defined aging aircraft flight profile deviation stabilizer. In the case when "Back" is on at high altitude and a small distance from the airport, the points C1, C2, C3 are displaced in the runway of the airfield to a distance at which the reduction will occur with the calculated angle of the trajectory. Thus, in the "Return" is provided by the output plane on the shortest path to the zone of the landing beacons RSBN with a reduction to the height of preplant maneuver. The ultimate goal is to derive preplant maneuver the aircraft in such a region of airspace where there is sure "grip" airborne signals MRC and timing.

Control of the airplane during landing approach Approach - it preplant maneuver the aircraft within range of CRM and SRM. The objective of this phase is to provide a precise conclusion on some aircraft to the runway threshold from which limited visibility would do well to finish the pilot landing manually, visually oriented.

After 3 ... 5 s after entering the aircraft 1.5 - km corridor relative to the runway and the stability of the CRM and SRM NCP goes to interact with ILS landing PRMG group (including CRM, SRM and planting repeater rangefinder) on and off from the interaction with RSBN ground beacon. ACS goes from mining mode to stabilize the aircraft LZP - on the runway - the signals of the beam deviation from the MRC . To this end, the trajectory calculator circuit roll channel ACS generates in law

.

Signal is the primary control signal, which is similar to the signal lateral deviation , because at small linear lateral deviation of the aircraft from the runway is defined as , where - current distance from the aircraft to the localizer.

Signal by analogy with the signal provides damping of oscillations of large lateral movement.

Inertial filters provide filtering high frequency noise in the signal and its derivative .

ACS longitudinal channel crossing timing of the beam generates a control signal given excessive overload or given pitch angle, for example, the laws of

; .

Expressions main control signal equivalent signal , and the signal like provides vibration damping large longitudinal movements.

An important feature of the contours of the trajectory control laws is the variability of their dynamic characteristics, depending on the distance to the beacon and .

At constant values ​​of the coefficients of control laws at large distances from the runway for small deviations and angular deviations and also small, small, respectively, and control signals. Transients sluggish. As you approach the runway distance to the corresponding beacon decreases, and signals and under the same mistakes and increase. This can result in an increase of the oscillatory process control and even the loss of stability of the circuit. Therefore auto-director or management have to disable. Thus, providing automatic landing gear ratios requires regulation control laws depending on the distance to the runway. In some onboard complex software used method of changing the coefficients of control laws. So in the ABSU-154-2 and a reduction in the time constants of the roll channel is discretely on the command "Capture glideslope" and "H-250 m," and pitch channel Command altimeter "H-250 m" and "H-100 m." At a height of 30 m off the automatic mode and a further approach is carried out manually.