JP2009145134A - Precision approach radar system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a precision approach radar system capable of performing timely and effective guidance control to an aircraft under landing approach, and reducing an operation load for the guidance control. <P>SOLUTION: Each observation position of the aircraft acquired repeatedly is smoothed by using a prediction filter, and a prediction position after elapse of a prescribed time width is calculated, and the newest smoothed position and the prediction position are symbolized and displayed. As for the prediction position, a standard deviation to the prediction position is calculated as its position error, and the result is displayed in piles two-dimensionally on the periphery of the symbolized prediction position as a probabilistic existence range of the aircraft. In addition, when calculating the position error, not only observation accuracy of the radar but also a processing error characteristic of the prediction filter are taken into consideration as error factors. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a precision approach radar system that predicts and displays a future position based on acquired position information while acquiring position information of an aircraft along a landing approach path.

  The precision approach radar acquires the three-dimensional position of the aircraft that has entered the landing posture, and expresses the radar echo along the landing approach path (Elevation, hereinafter referred to as EL) and direction (Azimuth, hereinafter referred to as AZ). ) Is displayed on two display screens. That is, the altitude and distance of the approaching aircraft are displayed on the EL screen, and the azimuth and distance are displayed on the AZ screen relative to each other using the radar echo as a reference (see, for example, Patent Document 1).

Conventionally, in these displays, radar echoes converted into analog video signals using a CRT or the like having afterimage characteristics have been displayed, but recently, due to advances in digital processing techniques for radar signals, In addition to removing unnecessary reflection components and the like, the target aircraft can be extracted and displayed in a symbol format, enabling screen display with improved visibility. In addition to symbol display, as a reference to know the variation in observation position, for example, a line corresponding to the angular resolution of the radar called control slash is displayed in the angle direction, or the position of the aircraft observed by the radar The radar information is subjected to various information processing and signal processing such as smoothing processing using a prediction filter. For example, in Patent Document 1, an altitude difference between a target aircraft that is approaching guidance and a glide path on a landing approach road is calculated and displayed as a specific numerical value on a display screen.
Japanese Patent Laid-Open No. 5-11041 (3rd page, FIG. 2)

  In landing guidance control using a precision approaching radar, the controller monitors the display while flying the aircraft along the landing approach path and guides it to the runway. For guidance, the aircraft side is instructed in the direction of flight based on the difference between the observation position by the radar and the landing approach, and further guidance is given while predicting the future position of the aircraft that will continue to enter based on the instruction. repeat. That is, it is necessary to continuously and accurately predict the future position of the aircraft within a short time immediately before landing, and signal processing, information processing, and the like for supporting this are desired.

  However, in the conventional precision approach radar system, the latest observation position by the radar is subjected to various signal processing, and then the aircraft position is displayed on the display screen. With a time delay of. In addition, in the case of symbol display, it is displayed on the screen as the pinpoint position, and the range of the true position variation with respect to this display position is not provided. In addition, the accuracy of observation in the distance direction and the angle direction of the radar itself and errors during signal processing, particularly errors in smoothing processing by a prediction filter, which are important factors of dispersion, are reflected. Absent. For this reason, it is not easy to predict the future position of the aircraft from such a screen display while the position of the aircraft changes with time. Therefore, guidance instructions for aircraft are not always timely and efficient, and the guidance control operation itself, which repeatedly predicts the future position while giving guidance instructions to the aircraft, is not light in workload. It was. In addition, business execution was accompanied by advanced skills and experience, as well as long-term operational training.

  The present invention has been made in consideration of the above-described circumstances, and performs a precise approach approach radar that performs timely and efficient guidance control on an aircraft that is approaching landing and reduces the work load of the guidance control. The purpose is to provide a system.

  To achieve the above object, the precision approach radar system according to the present invention obtains position information of an aircraft and displays the position information on the display screens of elevation and azimuth along the landing approach path. In the radar system, aircraft detection means for detecting the aircraft from the observed radar echo and acquiring the observation position in time series together with the observation time, and smoothing the observation position of the aircraft acquired in time series using a prediction filter However, the smoothing means for calculating the smooth position and speed of the aircraft at the latest observation time, and based on the calculation result of the smoothing means, the prediction time after the preset time width has elapsed from the latest observation time. Predicting means for calculating the predicted position and predicted position error of the aircraft, and the predicted position and predicted position error of the aircraft by the predicting means, And having a display means for displaying together with the observation position or smooth position in the serial latest observation time to the display position on the display screen of the elevation plane and azimuth plane corresponding to each position.

  According to the present invention, it is possible to obtain a precision approaching radar system capable of performing timely and efficient guidance control on an aircraft that is approaching landing and reducing the work load of the guidance control. it can.

  The best mode for carrying out the precision approach approach radar system according to the present invention will be described below with reference to FIGS.

  FIG. 1 is a block diagram showing the configuration of one embodiment of a precision approach radar system according to the present invention. The precise approach radar system illustrated in FIG. 1 includes a radar unit 11, a target detection unit 12, a smoothing processing unit 13, a predicted position calculation unit 14, a position error calculation unit 15, a display processing unit 16, an operation display unit 17, And a system time generator 18.

  The radar unit 11 repeatedly transmits and receives pulsed radar signals within a predetermined elevation angle range and azimuth angle range, and acquires radar echoes. The target detection unit 12 detects the target aircraft from the radar echo, and sequentially acquires the observation position and the observation time as time elapses. Based on the observation position and observation time from the target detection unit 12, the smoothing processing unit 13 smoothes the observation position using a prediction filter such as an α-β filter, for example, and smoothes the smooth position and speed at each observation time of the aircraft. Is calculated.

  Based on the results of these smoothing processes, the predicted position calculation unit 14 indicates the predicted position of the aircraft at the predicted time after a predetermined time span from the observation time, and the predicted position error calculation unit 15 indicates the predicted position error. calculate. The time span from the observation time to the predicted time at this time can be set in advance for each part or can be set by an operator. In the present embodiment, the setting by the operator is received from the operation display unit 17 described later. The display processing unit 16 edits a display screen including the calculation results of the predicted position calculation unit 14 and the position error calculation unit 15 and the observation position in the target detection unit 12 or the smooth position in the smoothing processing unit 13. Various display processes are performed to generate display data, which are sent to the operation display unit 17. The operation display unit 17 displays the display data from the display processing unit 16 on the display screen, accepts an input operation of a time width from an observation time to an estimated time by an operator or the like, and stores the contents as the predicted position calculating unit 14 and It is sent to the position error calculator 15. The system time generation unit 18 generates system time information and sends it to each unit in the system.

An example of a display screen in the operation display unit 17 is modeled and shown in FIG. In the example shown in FIG. 2, this display screen is composed of two planes, that is, an EL screen 21 that displays the position of the EL plane of the aircraft, and an AZ screen 22 that displays the AZ plane. In addition to the range marker 23 indicating, a glide path cursor 24 is displayed on the EL screen 21 as a landing approach path, and a course line cursor 25 is displayed on the AZ screen 22. The position of the aircraft is symbolized and displayed on each screen, and in this embodiment, the latest smooth position symbol 26 is a square filled with a tag 26a representing the flight number. Further, the previous smooth position symbol 27 is displayed by a white square. The predicted position symbol 28 at the predicted time after a predetermined time width from the observation time is symbolized as “*” and overlapped with the predicted position error range 29 (29 _EL or 29 _AZ ) calculated as a two-dimensional range on each screen. They are also displayed. As will be described later, in this embodiment, the two-dimensional range is based on the standard deviation with respect to the predicted position.

  Next, the operation of the precision approaching radar system of the present embodiment configured as described above will be described with reference to FIGS. 1 and 2, the flowchart of FIG. 3, and the explanatory diagram of FIG. FIG. 3 is a flowchart for explaining the operation of the embodiment of the precision approach radar system according to the present invention illustrated in FIG.

First, various initial settings including the setting of the time width (t _PS ) between the observation time and the predicted time are made through the operation display unit 17 by an operator or the like, for example (ST301). Next, a pulsed radar signal is repeatedly transmitted from the radar unit 11 to the coverage of a predetermined elevation angle range and azimuth angle range, and the received radar echo is sequentially transmitted to the target detection unit 12. A typical example of main performance specifications of the radar unit 11 is shown in Table 1 (ST302).

The target detection unit 12 detects the aircraft as a target from these radar echoes sequentially sent from the radar unit 11, acquires and the observation position X _M and measurement time t _M. When there is an aircraft in the radar coverage, for example, the observation position X _M and the observation time t _M are acquired in time series sequentially for each search cycle T of the radar unit 11 and sent to the smoothing processing unit 13. (ST303).

The smoothing processing unit 13, with respect to the observation position X _M sequentially acquired along these time to carry out the smoothing process using the prediction filter. When a case where an α-β filter is applied as the prediction filter is exemplified, smoothing processing is performed by the following equations (1) to (3).

  That is, each time the latest observation position is sequentially sent from the target detection unit 12, the smooth position with respect to the current observation position is calculated based on the previous predicted position based on the previous predicted position, and the smoothing speed is calculated based on the expression (2). Calculated. In addition, the predicted position at the next observation time is calculated by Equation (3). Then, the calculated smooth position and smooth speed at the latest observation time are sent to the predicted position calculation unit 14 and the position error calculation unit 15 together with the observation time (ST304).

Next, the predicted position calculation unit 14 calculates the predicted position at the predicted time after the elapse of the time width (t _P−S ) set in step ST301 from the latest observation time, and the smoothed position calculated by the smoothing unit 13 and Based on the smoothing speed, the following equation (4) is used for calculation. In this equation (4), it is assumed that the position and speed of the aircraft are expressed by an orthogonal coordinate system including three axes of x, y and z axes. The predicted position at the calculated predicted time is sent to the display processing unit 16 (ST305).

At the same time, the position error calculation unit 15 calculates a predicted position error for the predicted position at the predicted time calculated by the predicted position calculation unit 14. In the present embodiment, the predicted position error is calculated based on the observation accuracy of the radar unit 11 exemplified in Table 1 and the error characteristic of the α-β filter that is a prediction filter in the smoothing processing unit 13 (5). ) To calculate the variance of statistics.

Here, the calculation procedure of the smooth position variance value σ _XX ² , the smooth position velocity covariance value σ _XV ² , and the smooth velocity speed variance value σ _VV ² in Equation (5) will be described in detail below. The observation position of the aircraft acquired by the radar unit 11 for each search cycle T is sequentially sent to the smoothing processing unit 13 and smoothed by the α-β filter. Then, the variance value of the error accompanying the smoothing process at this time is set to the values calculated by the following equations (6), (7), and (8).

Here, T is a search cycle of the radar unit 11 and corresponds to T in Table 1, for example. α and β are filter constants of the α-β filter. Further, σ _O ² is the observation accuracy of the radar unit 11. For example, if σR in Table 1 is a distance observation error, σAZ is an azimuth direction, and σEL is an angle observation error in the elevation direction, these observations expressed in a polar coordinate system. The error can be calculated by converting it into an orthogonal coordinate system by the following equation (9). Note that R, θ, and φ represent aircraft observation positions in polar coordinates, as shown in FIG.

Thus, the variance value representing the predicted position error at the predicted time takes into account the variance σ _O ² due to the observation accuracy of the radar unit 11 according to Equation (9) and the influence of the α-β filter in the smoothing processing unit 13. Smooth position variance σ _XX ² , smooth position velocity covariance σ _XV ² , and smooth velocity velocity variance σ _VV ² are calculated by equations (6) to (8), respectively, and using these calculation results, equation (5) Calculated based on That is, both the radar observation accuracy and the prediction filter characteristics are considered. Then, the predicted position error at the calculated predicted time is sent to the display processing unit 16 (ST306).

  The display processing unit 16 receives the prediction results from the predicted position calculation unit 14 and the position error calculation unit 15 and the smoothed position in the smoothing processing unit 13, and edits the display screen illustrated in FIG. In editing the display screen illustrated in FIG. 2, the range marker 23, the glide path cursor 24 and the course line cursor 25 corresponding to the landing approach road are edited based on, for example, drawing data prepared in advance. For each of the latest smooth position symbol 26, the previous smooth position symbol 27, and the predicted position symbol 28, the process of converting the position of each aircraft received from each part into the corresponding display position on the display screen coordinates And edit to display each symbol corresponding to that position.

In addition, for the predicted position error range 29 (29 _EL and 29 _AZ ), the predicted position variance value calculated based on the equation (5) is projected onto each display surface of the EL screen 21 and the AZ screen 22 to display each display. In this embodiment, editing is performed so as to superimpose the value on the predicted position symbol 29 as a range centered on the predicted position. Do. The two-dimensional range can also be gradation or color-coded according to the size of the value, enabling editing with improved visibility. The display data generated by these display processes is sent to the operation display unit 17, and the operation display unit 17 displays it (ST307).

  Thereafter, when an operation such as setting change is performed from the operation display unit 17 by an operator or the like (Y in ST308), these operations are accepted by the operation display unit 17 and the contents are reflected (ST309), and the operation ends. Until the above is instructed, the operation from ST302 described above is repeated (ST310).

  As described above, in the present embodiment, the observation position of the aircraft obtained repeatedly is smoothed using the prediction filter, the predicted position after the lapse of the predetermined time width is calculated, and these latest smoothed positions are calculated. And the predicted position are symbolized and displayed. In addition, for the predicted position, a standard deviation with respect to the predicted position is calculated as a position error, and this is superimposed and displayed in two dimensions around the predicted position symbolized as the stochastic existence range of the aircraft. Yes. Further, when calculating the position error, not only the radar observation accuracy but also the processing error characteristic in the prediction filter is taken into consideration as an error factor, thereby improving the reliability.

  This makes it possible to simultaneously and more visually grasp the latest smoothed position, the predicted position after a predetermined time, and the probable presence range for the predicted position for an aircraft that is approaching landing. At the same time, foresight information on the future position is provided, so that it is possible to perform timely and efficient guidance control on the aircraft that is approaching landing, and precise measurement that can reduce the work load of the guidance control. An approach radar system can be obtained.

  Note that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above-described embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

1 is a block diagram showing an embodiment of a precision approach radar system according to the present invention. Explanatory drawing which shows an example of a display screen. The flowchart for demonstrating operation | movement of the precise measurement approach radar system illustrated in FIG. Explanatory drawing for demonstrating the aircraft position in a polar coordinate.

Explanation of symbols

11 radar unit 12 target detection unit 13 smoothing processing unit 14 predicted position calculation unit 15 position error calculation unit 16 display processing unit 17 operation display unit 18 system time generation unit

Claims (5)

In the precise approach radar system that acquires the position information of the aircraft and displays these position information on the display screen of the elevation and azimuth plane along the landing approach path,
Aircraft detection means for detecting the aircraft from the observed radar echo and acquiring the observation position in time series together with the observation time;
Smoothing means for calculating the smooth position and speed of the aircraft at the latest observation time while smoothing the observation position of the aircraft acquired in time series using a prediction filter;
Prediction means for calculating the predicted position and predicted position error of the aircraft at the predicted time after the passage of a preset time width from the latest observation time based on the calculation result in the smoothing means;
A display for displaying the predicted position and predicted position error of the aircraft by the prediction means together with the observation position or the smooth position at the latest observation time at the display position on the display screen of the elevation surface and the azimuth surface corresponding to each position. And a precision approach radar system. Furthermore, it has an operation input means for accepting a designation operation of a time width from the observation time to the prediction time in the prediction means input from an operator,
2. The precise approach radar system according to claim 1, wherein the prediction unit calculates a predicted position and a predicted position error of the aircraft at a predicted time based on an elapsed time received by the operation input unit.   3. The precision approach radar system according to claim 1, wherein the predicted position error in the prediction means is calculated based on an observation accuracy of the precision approach radar system and an error characteristic of the prediction filter.   2. The display unit according to claim 1, wherein the display unit displays the predicted position error as a two-dimensional range superimposed on a display position of the predicted position of the aircraft on the display screen of the elevation surface and the azimuth surface. 4. The precise approach radar system according to any one of items 3 to 3.   5. The display unit according to claim 1, wherein the display unit displays a range in which the predicted position error is displayed in two dimensions by gradation or color coding according to the value of the predicted position error. The precision approach radar system described in the paragraph.

Images