JP2646023B2 - MLS receiver - Google Patents

Description

The present invention relates to an MLS (Microwave Land) mounted on an aircraft.
ing System) related to the receiver.

(Prior art) MLS is also called a precision approach and landing assistance system for aircraft using microwaves (5031 to 5090.7MHz), and was developed with the aim of allowing aircraft to land safely even when visibility is poor. It is.

The MLS consists of ground equipment including a transmitting antenna installed at an airport and a receiver mounted on an aircraft. The ground equipment uses azimuth (azimuth) for approaching (entering)
The guide azimuth) and the elevation (height) guidance device are the basic components, and the reach of radio waves emitted in a time-division manner from those devices is 20 nautical miles in the approach direction of the runway. .

The MLS receiver on the aircraft receives the MLS signals emitted from these ground devices, and performs angle measurement in the MLS receiving angle measurement unit, so that the position of the own device can be determined by the azimuth (azimuth) angle and elevation (high or low). ) It can be known as a corner. In addition, the MLS receiver calculates the difference between the preset approach and landing course and the position of its own aircraft, outputs a difference signal, and outputs the azimuth and elevation deviations to the cockpit course excursion meter (CDI meter). Display the amount of each. The pilot
By maneuvering the aircraft such that both the azimuth and elevation deviations are zero, it is possible to approach and land along the set approach and landing course.

In addition, by installing a back azimuth (backward direction) guidance device at the airport as a ground device, guidance at the time of landing return and takeoff of the aircraft can be performed within a range of 5 nautical miles from the airport in the opposite direction to the approach azimuth. .

In this way, the approach azimuth and back azimuth coverage areas are opposite to each other across the runway, so when the aircraft enters the airport, it is guided by the approach azimuth signal, but at the time of the go-around, the back azimuth signal is output. Must be used. Therefore, the difference signal output from the MLS receiver to the course displacement meter over the runway where both approach azimuth and back azimuth signals can be received,
It is necessary to switch from the approach azimuth to the difference signal relating to the back azimuth.

Therefore, the control panel of the conventional MLS receiver has a switch for switching between the approach azimuth display and the back azimuth display, and the pilot has to perform this switching operation as needed.

(Problem to be Solved by the Invention) In the conventional MLS receiver as described above, when going back to landing, the pilot must operate a switch for switching between approach azimuth display and back azimuth display. However, performing such an operation in a time-critical emergency such as a go-around would be a heavy burden on the pilot, and a major issue related to the safety of crew and passengers.

The present invention has been made in order to solve such a problem, and an object of the present invention is to provide an MLS receiver that automatically switches from an approach azimuth display to a back azimuth display during a go-around.

(Means for Solving the Problems) An MLS receiver according to the present invention includes an MLS receiving angle measuring unit, a body attitude sensor for measuring a pitch angle of the body, and an arithmetic control unit, and the arithmetic control unit includes: Receiving the MLS signals output from the MLS receiving angle measuring unit, that is, the intensity of the approach azimuth signal and the back azimuth signal and the pitch angle signal of the aircraft from the aircraft attitude sensor, the deviation of the approach azimuth and the deviation of the back azimuth The output signal switching unit is controlled based on the determination result to determine whether the output to the coarse eccentricity meter should be the approach azimuth deviation or the back azimuth deviation. The display of the output of the course deviation meter when the aircraft makes a return-to-landing can be automatically switched from the approach azimuth display to the back azimuth display. And features.

(Operation) In the present invention, the deviation (difference) signal output to the course deviation meter of the aircraft at the time of go-around is automatically switched from the deviation signal of the approach azimuth to the deviation signal of the back azimuth. This eliminates the need for the pilot to manually switch the switch.

(Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a block diagram showing an embodiment of the present invention, in which an antenna 1, an MLS receiving angle measuring unit 2, an airframe attitude sensor 3, an output signal switching unit 4, an arithmetic control unit 5, and a course displacement meter 6 are included. Including.

In the MLS receiver according to the present invention, the operation control unit 5 determines whether the deviation signal to be output to the course deviation meter 6 is the approach azimuth deviation or the back azimuth deviation, and controls the output signal switching unit 4. To perform automatic switching.
This operation will be described with reference to FIG.

Now, consider the case where the aircraft lands at the airport. When the aircraft approaches 20 nautical miles from the airport, the approach azimuth (guide) signal from the approach azimuth antenna 21 installed on the center extension of the runway and the elevation antenna installed next to the runway datum point (Not shown) and an elevation (induction) signal
The MLS angle measuring unit 2 becomes capable of receiving. Courses to be approached and landed from the ground antenna, that is, the approach azimuth setting angle and elevation setting angle data are also transmitted as basic data, and these data are also ML.
Reception is possible at the S reception angle measurement unit 2. An antenna 22 for back azimuth is installed on the center extension line on the runway entrance side, and assists in returning to the landing. Needless to say, the emission of the approach azimuth signal, the back azimuth signal, the elevation signal, and the like are performed in a time-division manner, and the identification of these signals is performed based on the identification code added to the head of each signal.

The MLS reception goniometer 2 uses the difference between the approach azimuth setting angle and the approach azimuth angle measurement value of the own device and the difference between the elevation setting angle and the elevation measurement angle value of the own device as the approach azimuth deviation and the elevation deviation, respectively. Mainly goes to the output signal switching unit 4. MLS angle measuring unit 2 also
The reception intensity of the approach azimuth signal and the back azimuth signal is output to the arithmetic and control unit 5 each time it is received.

On the other hand, the pitch angle, which is one of the parameters representing the attitude of the own aircraft, is always output from the body attitude sensor 3 mounted on the aircraft to the arithmetic control unit 5, and the arithmetic control unit 5 always outputs the nose of the own aircraft. The angle of the lift, that is, the pitch angle can be known. As the body attitude sensor 3, for example, a vertical gyro is used.

 The operation of the arithmetic and control unit 5 will be described.

The arithmetic control unit 5 determines whether the deviation signal to be output to the course deviation meter 6 should be the approach azimuth or the back azimuth based on a predetermined condition, and sends the control signal to the output signal switching unit 4. send. Specifically, the arithmetic and control unit 5 compares the signal strengths of the approach azimuth and the back azimuth when the pitch angle obtained from the body attitude sensor 3 is smaller than a certain angle, for example, 6 °, and the signal strength is strong. The output signal switching unit 4 is controlled so as to select one of them. On the other hand, when the pitch angle becomes 6 ° or more, the output signal switching unit 4 is controlled so as to select the back azimuth deviation once the signal intensity of the back azimuth exceeds the signal intensity of the approach azimuth.

If this determination is made only with the signal strengths of the approach azimuth and the back azimuth, the signal strengths near the runway are considered to change as shown in FIG. 2, and therefore the following problem arises. That is, the approach azimuth signal increases in intensity as the aircraft enters the runway, reaches a peak just above the approach azimuth antenna 21, and hardly disappears thereafter. On the other hand, the back azimuth signal hardly occurs until the aircraft reaches the back azimuth antenna 22, but peaks immediately above the back azimuth antenna 22, and then gradually decreases as the aircraft moves away from home. From this, approach azimuth at the stage of approaching the runway, back azimuth near the runway threshold, approach azimuth, and then near the stop end of the runway, the back azimuth is rapidly switched, and each time the course The deflection of the needle of the displacement meter 6 becomes discontinuous, which is not preferable.

On the other hand, according to this method in which the signal strength of the approach azimuth and the back azimuth and the nose-up angle (pitch angle) of the own aircraft are determined, the switching from the approach azimuth to the back azimuth at the time of the landing go-around Can be performed smoothly. That is, since the pitch angle of the aircraft is smaller than a certain value at the approach stage, the approach azimuth 6 and the stronger azimuth signal strength, in this case, the approach azimuth signal are output to the course excursion meter 6.

If for some reason just before landing the landing is canceled and it is necessary to jump up again, the pilot will always raise his nose. For example, the pitch angle is set to + 12 °. In this case, although the pitch angle is larger than a predetermined angle (for example, 6 °), the arithmetic control unit 5 determines the approach azimuth deviation from the course eccentricity meter 6 because the signal intensity of the back azimuth has not yet exceeded the signal intensity of the approach azimuth. Continue to output to.

Thereafter, when the aircraft approaches the runway threshold, as shown in FIG. 2, the signal intensity of the back azimuth becomes stronger than that of the approach azimuth. At this point, the arithmetic and control unit 5 controls the output signal switching unit 4 so as to output the back azimuth deviation to the course deviation meter 6. After that, since the aircraft keeps climbing while keeping its pitch angle, the back azimuth deviation is continuously output to the course deviation meter 6,
There is no switch to approach azimuth over the runway. Beyond the runway stop-end, the signal strength of the back azimuth will be stronger than the approach azimuth, and the back azimuth will be selected regardless of the aircraft's pitch angle. The guidance of the aircraft is performed by the azimuth guidance signal. At the time of re-entering for landing, the pitch angle is not so large and the signal intensity is larger than the approach azimuth signal intensity, so the display of the course displacement meter automatically switches from the back azimuth signal to the approach azimuth signal. Can be

In addition, since the display of the approach azimuth deviation and the display of the back azimuth deviation are performed by the same course eccentricity meter 6, a means for distinguishing both displays, for example, an indicator light, which one is currently displayed? May be identified.

(Effects of the Invention) As described above, the present invention automatically outputs the output of the course eccentricity meter even when the pilot does not need to operate the switch for approach azimuth and back azimuth when the go-around is required. Switching from approach azimuth to back azimuth can reduce the burden on the pilot in the event of an emergency such as a return-to-landing, and has the effect of ensuring the safety of occupants and passengers.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an MLS receiver showing an embodiment of the present invention, and FIG. 2 is a diagram showing signal strengths of approach azimuth and back azimuth near an airport. 1 ... antenna, 2 ... MLS angle measuring section, 3 ... body attitude sensor, 4 ... output signal switching section, 5 ... arithmetic control section, 6
…… Course excursion meter.

Claims (1)

(57) [Claims] 1. An MLS receiving angle measuring unit for receiving an approach azimuth signal and a back azimuth signal transmitted from an approach azimuth antenna and a back azimuth antenna disposed on an extension of the runway and performing angle measurement, respectively. An output signal switching unit that switches an angle measurement output of the MLS reception angle measurement unit, a body attitude sensor that measures a pitch angle of the body,
An arithmetic control unit, the arithmetic control unit determines the pitch angle of the airframe and the reception intensity of the approach azimuth signal and the back azimuth signal when the aircraft performs a go-around, and switches the output signal. An MLS receiver characterized in that said output signal switching section is controlled so as to switch an angle measurement output from a section to a course displacement meter to either an approach azimuth or a back azimuth.