JPH01229910A - Navigating device - Google Patents

Abstract

PURPOSE:To display the efficiency as an independent navigating device continuously at all times with high accuracy and at high data rate, by providing a data base, a pseudo radar image data generating unit, an image converting unit etc. CONSTITUTION:Based on a reference of the present position detected by an inertial navigation system device 14, the data of the surface height in the peripheral area is read out from a data base 11, and inputted to a pseudo radar image data generating unit 13, thereby to obtain a pseudo radar image data. On the other hand, an actual radar echo obtained by a radar antenna 15 and a radar receiver 16 is inputted to an image converting unit 17 to be converted into an actual radar image data. The pseudo radar image data and actual radar image data obtained in the above manner are inputted to a comparing calculator 18 for comparison therebetween. The pseudo radar image data covers a range wider than the actual radar image data, and the range closest to that of the actual radar image data within the range covered by the pseudo radar image data is detected by the distribution difference of color and brightness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a navigation device used in a flying vehicle such as an aircraft or a helicopter.

(Prior Art) Currently, as navigation devices mounted on a flying object such as an aircraft, there are independent navigation devices such as IN5 (inertial navigation device), radio navigation devices using satellites, and the like. Radio navigation devices generally have drawbacks such as low data rates and limited usable areas, but some, such as GPS (Global Positioning System), can achieve positioning accuracy throughout the world. On the other hand, INS has a high data rate and can track posture changes well, but it has the disadvantage that position errors disappear completely over time.

Therefore, a GPS-INS composite navigation device that has the advantages of both is being developed. This device has the advantage of high purity and a higher cheater rate. but,
Because GPS signals are transmitted from external radio wave sources other than your own, their functionality can easily deteriorate due to interference, jamming, system failure, or the intentions of the GPS satellite operator. In this case, The advantage of using an INS as an independent navigation device will be lost, and the system will also suffer from condyle.

On the other hand, in order to overcome the above-mentioned drawbacks, navigation devices using a topography altitude verification method are being developed. This device is mounted on the aircraft and provides altitude data (
Terrain altitude data) are registered in advance, and the terrain altitude data is calculated by comparing (filtering) the measured altitude above the ground based on wave height changes with the estimated altitude above the ground obtained by subtracting the terrain altitude data registered from the barometric altimeter. The search is performed within the base of , and the optimal estimation of the position is performed based on this search.

To limit the search area, refer to INS instructions (1).The INS navigation error can be estimated by such position estimation.

However, although this navigation device has the advantage of being a self-sustaining system, it only verifies the average altitude data within a section and the height above the ground directly below the aircraft using a radio altimeter. be. Because the amount of information is so small, it is possible to estimate the wrong location,
Estimated rank! They are difficult to find, and their accuracy depends on the terrain and flight conditions, making it impossible for them to demonstrate continuous performance at all times.

(Problems to be Solved by the Invention) As described above, there has been no conventional navigation device that has high accuracy and a high data rate, and can constantly and continuously demonstrate the performance as an independent navigation device.

This invention was made in order to solve the above-mentioned problems, and its purpose is to provide a navigation device that is highly accurate and has a high data rate, and can constantly and continuously demonstrate the performance as an independent navigation device. do.

[Structure of the invention] (Means for solving the problem) In order to achieve the above object, the navigation device according to the present invention has the following features:
A database that registers ground surface and altitude data for each subdivision in advance, a self-position detection means that detects one's own position through internal processing, and a self-position detection means that detects one's own position through internal processing. pseudo radar image data generation means for reading data from the database and generating pseudo radar image data from the read data;
a radar device that measures an actual radar echo; a real radar image data generation means that generates real radar image data from the radar echo measured by the radar device;
and a position estimating means for comparing the pseudo radar image data and the real radar image data and estimating the most similar part between the two as the current position, and if necessary, estimating the current position obtained by the position estimating means. The self-position detecting means includes a correction means for correcting the output of the self-position detecting means based on a difference from the position obtained by the self-position detecting means.

(Function) In the navigation device having the above configuration, ground surface and altitude data are recorded in a database for each small section in advance, and the self-position is detected by the internal processing of the self-position detecting means, and this detected position 1 is used as a reference. Then, the surrounding ground surface and altitude data are read from the database, and pseudo radar image data is generated from the read data. On the other hand, actual radar echoes are measured by a radar device, and actual radar image data is generated from the measured radar echoes. Then, the pseudo radar image data and the actual radar image data are compared, and the portion of the two that is approximated is estimated to be the current position. If necessary, the accuracy can be further improved by correcting the output of the self-position detecting means based on the difference between the current position obtained by the position estimating means and the position obtained by the self-position detecting means. .

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

Figure 1 shows its configuration, and the database 11 contains ground surface/altitude data, such as elevation data for each subdivision ground surface created by the Geospatial Information Authority of Japan, forests, fields, urban areas, etc.
Type data indicating the type of ground surface such as rivers, buildings such as towers and beer, and the types of their materials are registered, and for each type data, radio wave reflection is recorded according to the type of radar installed on the aircraft. Ratio data such as rate and infrared emissivity are registered. Incidentally, the ratio data may be registered in a pseudo radar image data generation unit (PRIG) 13, which will be described later.

The interface 12 receives the position information from the lN514, reads altitude and ground surface data around that position from the database 11, and sends it to the PRIG13.
This is to send altitude and ground surface data around an arbitrary position completely different from the designated position of N519 to PRIG13.

PRTG13 normally calculates the radio wave reflectance and infrared radiation corresponding to each surface based on altitude and ground surface data sent with the current position data of IN514 as a reference, taking into account radar parameters such as beam scanning width and beam scanning speed. The radar echo on the ground surface is estimated and calculated using ratio data such as rate, and the color and brightness of each small section of arbitrary size are determined to generate pseudo radar image data. However, when the onboard radar outputs images in the slant range, the process of converting ground range data to slant range data is performed using the radar echo estimation calculation based on the altitude data in the database 11 and the ground altitude measurement value below. Must be done before or after. The altitude above the ground is based on the measurement value of the radio altimeter mounted on the aircraft, or the altitude data of the terrain taken into consideration from the measurement value of the barometric altimeter (database 1).
It is obtained by subtracting the data within 1). The above data conversion process is performed in consideration of the pitch angle and roll angle of the aircraft.

The generated image data is stored in the frame memory within the PRIG 13 (or may be stored in the comparison calculation II! 118).

On the other hand, the radar antenna 15 and the radar receiver mR16 detect actual radar echoes during flight and output images, and this radar echo image is input to the image conversion section 17. This image conversion unit 17 converts one input image into a rask image using a scan converter, and further converts the input image into a rask image, and further converts the input image into a rask image.
After digital (A,/D) conversion and digital data, the pseudo radar image data in the PRIG 13 is converted into real radar image data by the same former 71.

This real rate image data is stored in the frame memory in the image converter 17 (it may also be stored in the comparison computer 18).

The comparison computer 18 compares the pseudo image data from the PRIG 13 and the real radar image data from the image converter 17 using part or all of the frame memory, and estimates the true current position from the comparison result. to do,
The comparison timing is controlled by one controller. The current position estimated by this comparison calculator 18 is fed back to the IN 514 and is used for error correction.

The operation of the above configuration will be described below with reference to FIG.

FIG. 2 is a block diagram showing the concept of the position estimating means.

First, the current position detected by IN514! Using (block a) as a reference, ground surface altitude data around the area is read out from the database 11 and input to the PRIG 13 to generate pseudo radar image data (block b). On the other hand, the actual radar echo obtained by the radar antenna 15 and the radar reception 1fi 16 is input to the image converter 17 and converted into actual radar image data (block C).
.

The pseudo radar image data and real radar image data thus obtained are input to a comparator j[1i18, and the two are compared. Here, the pseudo radar image data covers a wider area than the actual radar image data, and within this area, the area (location) closest to the actual radar image data is detected by determining the difference in color and brightness distribution. do. At this time, for example, the color and brightness data of each pixel are compared, and the area where the least squares error within the comparison area is the smallest is considered to match the actual radar image data, and the reference position is set as the true current position. Block d) considered as position data. If there is no valid data in the frame memory in which the pseudo radar image data is stored, data in a wider area may be read out from the database 11 and compared.

In the above, the surrounding area has been searched based on the current position from lN514, and the optimal position has been estimated.
Output to the outside as position detection error of 4, or lN5
14 for error correction. In Figure 2, the solid line is (when correcting i position data, the dotted line is l
This shows the place to correct the ti structure of N514.

In an ideal case, the error between the position on the database 11 estimated as above and the true position mostly depends on the parcel size and precision of the registered data on the database 11, which is, for example, about 100rrL to 300m, INS
Considering that there is generally a divergence error of INM, , 'H, this accuracy can be said to be extremely high. In addition, all of the radar echo coverage white information, which is observation data, is used and compared with the registered data in database 11, and the current position is determined! Because it estimates the location, unlike conventional topographical height matching equipment, the amount of information is extremely large, initial acquisition is easy, the probability of estimating the wrong location is low, and it is also easy to follow the land that has been captured. The probability of losing sight is also very low.

Therefore, the navigation device with the above configuration has extremely high accuracy due to the error in the estimated position or the small section size and accuracy of the registered data in the database, and it can be compared with the registered data by conveniently using all the radar echo coverage white information. Since the current position is estimated using the INS, the data rate is extremely high, and since the position detected by the INS is used as a reference, it can constantly and continuously demonstrate its performance as an independent navigation device.

In the above embodiment, the display 92 as shown in FIG.
It is also possible to display an actual radar image on the display 20 by adding 1f to 0, or to use pseudo radar image data for preparation or simulation of ('f: open position - da echo).

[Effects of the Invention] As described above, according to the present invention, it is possible to provide a navigation device that is highly accurate, has a high data rate L1~, and can constantly and continuously exhibit the performance as an independent navigation device. ,

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a navigation device according to the present invention, and FIG. 2 is a diagram of a blower 2 for explaining the concept of the position estimating means of the embodiment. DESCRIPTION OF SYMBOLS 11... Database, 12... Interface, 13... Pseudo rate image data generation part (PRI)
G), 14...lN5 (inertial navigation device), 15...
Radar antenna, 1G... Radar receiver is machine, 17...
Stroke converter, 18... Comparison calculator, 19... Controller, 20... Display device. Applicant's agent Patent attorney Takehiko Suzue

Claims (2)

[Claims] (1) A database that registers ground surface and altitude data for each subdivision in advance, a self-position detection means that detects one's own position through internal processing, and the surrounding ground surface based on the position detected by this means, pseudo radar image data generation means for reading altitude data from the database and generating pseudo radar image data from the read data; a radar device for measuring actual radar echoes; A navigation device comprising a real radar image data generating means for generating radar image data, and a position estimating means for comparing the pseudo radar image data and the real radar image data and estimating the most similar part of both as the current position. (2) Claim 1, further comprising a correction means for correcting the output of the self-position detection means based on the difference between the current position obtained by the position estimation means and the position obtained by the self-position detection means.
Navigation equipment as described.