JPH06314060A - Navigation device - Google Patents

Abstract

PURPOSE:To stereoscopically display the position of a satellite and a receiving state on a celestial globe on a plane figure. CONSTITUTION:By receiving electric waves from plural satellites by means of a GPS receiver 13 so that a present position is measured, and stereoscopically displaying the position of the satellite from which the electric wave is received on the celestial globe on the plane figure with the present position displayed on the screen of a display 15 as center, position measuring accuracy decided from the positional relation of the satellite whose electric wave is caught and electric wave receiving conditions understood by comparing the position of the satellite with reception environment are intuitively grasped on the celestial globe stereoscopically displayed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a navigation device for stereoscopically displaying a satellite position and a reception state on a celestial sphere of a plane figure.

[0002]

2. Description of the Related Art GPS (Global Position)
The navigation device using the Ning System) has a built-in GPS receiver that captures radio waves emitted from a plurality of GPS satellites launched into six circular orbits at an altitude of 21,000 km and measures the current position. GPS receivers currently in practical use simultaneously receive the radio waves of up to eight satellites, each of which transmits the current time and orbital data, and calculate the distance to the satellite from the time difference between transmission and reception from each satellite. The current position can be specified as an intersection of spherical surfaces drawn with a distance to the current position centered on at least three satellites. However, if the satellites and the clocks on the receiving side do not completely match, the spherical distances from the three satellites do not intersect at a single point, so the time delay is introduced by receiving the radio wave from the fourth satellite and receiving. By solving the equation using the error of the side clock as an unknown number, accurate three-dimensional positioning of latitude, longitude, and altitude becomes possible. Based on this, in order to enable accurate positioning at any place on the ground at any time and any time, 3 satellites are placed in 6 circular orbits with different inclination angles, and 4 satellites are always placed everywhere. A satellite deployment plan is underway to ensure that the

However, even if the radio waves emitted by the four satellites can be perfectly captured, if the satellites are close to each other, the positioning error of the current position, which is obtained as the intersection of the spherical distances, increases. Positioning accuracy is 30m ~
It varies in the range of 200 m. Furthermore, even if the satellite is near the horizon and the elevation angle is small, reception obstacles due to high-rise buildings and trees will occur, and the decrease in distance detection accuracy will likely lead to deterioration in positioning accuracy. It has been found that positioning accuracy is affected more or less by. Usually, if you can only receive 3 satellites,
The latitude and longitude can be obtained from the three received radio waves, but for the altitude, since the data at the time when four satellites were being received is borrowed, the positioning accuracy will be further reduced.

On the other hand, such a decrease in the positioning accuracy of the GPS receiver is recognized by a user who is actually using it as a gap between the current position where the positioning is performed and the actual current position, and the deterioration is caused by the time zone and the receiving environment. It may be a cause of impairing the reliability of the GPS receiver itself, such as variations in degree. Therefore, in order to convince the user that the deterioration of the positioning accuracy is due to the satellite arrangement and the surrounding reception environment, it is possible to suggest on the screen the background of the positioning accuracy deterioration to the user who specified the satellite information display mode. It has come to be requested that various consideration be given.

For example, when a satellite information display mode is designated, a conventional navigation device having a display 1 for displaying the screen shown in FIG. 8 has the number of satellites capable of capturing radio waves at that time in the upper left corner of the screen. It is displayed together with the satellite mark 2 and the positioning possible time zone (not shown) and the like are displayed in a bar graph. However, this one only displays the number of satellites that can be captured, so the satellites are near the horizon and the elevation angle is small, and the radio wave is blocked by skyscrapers and trees, so the reception sensitivity seems to have decreased. Occasionally, the difference between the actual positioning error and the display of the number of satellites was received with a sense of discomfort. Therefore, in the satellite information mode, a navigation device equipped with the display 3 for displaying the screen shown in FIG. 9 has come to be used. This navigation device not only displays the number of satellites that can be captured by radio waves, but also plots their positional relationship with respect to the present location on the circular coordinates with a circular satellite mark 4, and Based on the azimuth angle and the elevation angle, the user can understand the reception environment that the user actually sees. Therefore, for example, a satellite closer to the center of the circular coordinates has a larger elevation angle and is closer to the overhead of the current position, and the direction from the north, south, east, and west directions indicated by the cross line passing through the center points of the circular coordinates. It is possible to visually comprehend the status of satellite placement, such as whether or not there are satellites. Therefore, for example, the positioning accuracy may decrease because the satellites form a group in a narrow range, or the positioning accuracy may decrease because the satellite has a sufficient elevation angle but the direction of the satellite is behind a building or tree. , Can be seen by analyzing the satellite constellation on the circular coordinates.

[0006]

The conventional navigation device described above displays the positional relationship of a plurality of satellites in a plane when the celestial sphere with the current position as the center is viewed from directly above the current position. It also has the advantage that the azimuth and elevation of each satellite can be easily analyzed visually.
Although it is possible to intuitively understand the relationship between the direction of the satellite and the traveling direction when determining whether the direction of the satellite is behind a building or a tree, a guideline for the elevation angle and height of the satellite is, for example, an elevation angle of 45 degrees. It is difficult to understand only roughly based on whether there is a satellite inside or outside the line, even if there are dense trees in the diagonal direction ahead and the satellites are hidden behind it. However, there is a problem that it is difficult to immediately judge the magnitude relationship between the angle of looking up at the tip of a tree and the elevation angle of the satellite read from the screen, and it is difficult to identify whether or not dense trees cause reception failure. It was

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a GPS receiver that receives radio waves from a plurality of satellites to position the present location, and a celestial sphere with a planar figure centered on the present location. It further comprises satellite position stereoscopic display means for stereoscopically displaying the position of the satellite that has received the radio wave.

Further, according to the present invention, the satellite position stereoscopic display means stereoscopically locates the position of the satellite specified by the azimuth angle and the elevation angle on the orbit of a three-dimensional celestial sphere about the present position in a two-dimensional orthogonal coordinate system. A two-dimensional display, comprising: a calculator for coordinate conversion to a position on the celestial sphere visually displayed and drawing, and a display for displaying the satellite position drawn by the calculator together with the stereoscopically displayed celestial sphere. An ellipse with an elevation angle of zero degrees centered on the current position in a Cartesian coordinate system, a crossing line indicating north, south, east, and west passing through the center of the ellipse, and a plurality of orbit lines having different azimuth angles intersecting at a point directly above the current position orthogonal to the ellipse. On the celestial sphere displayed stereoscopically with and, the radio wave captured satellite is displayed in dots based on its azimuth angle and elevation angle, and the radio wave captured satellite is scaled according to the relative azimuth angle relative to the current location. Or other characteristics such as displaying dots by distinguishing brightness, brightness, or color, and displaying dots by distinguishing size, brightness, or color depending on whether or not a satellite that has captured a radio wave is used for positioning. Is.

[0009]

According to the present invention, the GPS receiver receives radio waves from a plurality of satellites to measure the current position, and stereoscopically displays the position of the satellite receiving the radio waves on a celestial sphere with a plane figure centered on the current position. By doing so, it becomes possible to intuitively grasp the positioning accuracy determined by the positional relationship of the satellites captured by the radio waves, the radio wave reception status and the like which can be known from the comparison between the satellite position and the reception environment on the stereoscopic sphere.

[0010]

Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a schematic block configuration diagram showing an embodiment of a navigation device of the present invention, FIG. 2 is a diagram showing a relationship between a dot attribute for displaying a satellite position and a display area, and FIG. 3 is shown in FIG. FIG. 4 is a diagram for explaining the principle of coordinate conversion by a computing unit, FIG. 4 is a flowchart for explaining the operation of the navigation device shown in FIG. 1, and FIG. 5 is a step for determining the attributes of the display dots shown in FIG. It is a flow chart which shows one example.

The navigation device 11 shown in FIG.
A GPS receiver 13 that receives radio waves from satellites and measures the current position, centered on a computing unit 12 having a PU and a memory
Also, a key input device 14 for giving various inputs to the arithmetic unit 12 by key operation, or a display 15 for displaying an output of map data, satellite information, etc. is connected,
When the map near the current location read from the map information storage medium 16 such as a CD-ROM is displayed on the display 15, the current location determined by the GPS receiver 13 can be displayed on the map near the current location in an overlapping manner. here,
The arithmetic unit 12 and the display 15 constitute a satellite position stereoscopic display means for stereoscopically displaying the position of the satellite that has captured the radio wave on the celestial sphere centering on the current location. That is, in the computing unit 12, the GPS receiver 13 is centered around the present position.
The position of the satellite specified by the azimuth and elevation in the orbit of the three-dimensional celestial sphere is transformed into the position on the celestial sphere that is stereoscopically displayed in the two-dimensional Cartesian coordinate system, and is drawn. The display 15 is drawn by the computing unit 12. The satellite position is displayed together with the stereoscopic celestial sphere.

The celestial sphere on the display 15 has an ellipse with an elevation angle of zero degrees centered on the present location in a two-dimensional orthogonal coordinate system, a cross line that passes through the center of the ellipse and shows north, south, east, and west, and intersects the ellipse at the present location. The azimuth angle at the point directly above is different 8
Stereoscopic display is performed with the orbit line of the book. The satellites that have captured the radio waves are displayed as dots on the stereoscopic sphere that is stereoscopically displayed based on the azimuth and elevation. However, the display dot distinguishes the size and the brightness according to the area on the celestial sphere of the satellite that has captured the radio wave, and distinguishes the color according to whether or not the satellite is used for positioning. The above eight orbit lines are
For example, as shown in FIG. 2, considering the relative azimuth between the azimuth of the current location and the azimuth of the satellite viewed from the center of the earth, the clock with the highest azimuth at which the current azimuth and the satellite azimuthally overlap is the highest point. It is obtained by dividing the circumference, which turns 360 degrees in the direction and returns to the current position, into eight equal parts, each 45 degrees through the center of the circle. Here, the area divided by the eight orbital lines is divided into four areas: a front area, a left front area and a right front area, a left back and right back area, and a back area, and display dots are provided in each area. The size of is divided into four stages of extra large, large, medium and small,
The brightness is divided into two levels, light and dark, in the front area or the back area, and at the same time, the display dot color is displayed in green for satellites used for positioning and gray for satellites not used for positioning. The method is adopted. For information on whether or not the satellite that has captured the radio waves is used for positioning, add the current position information and the satellite position information to the G
It is supplied from the PS receiver 13 to the arithmetic unit 12.

By the way, the arithmetic unit 12 displays the position of the satellite identified by the azimuth angle α and the elevation angle β on the orbit of the three-dimensional celestial sphere about the current position, as shown in the display 1 shown in FIG.
In the two-dimensional X-Y coordinate system having the origin O (0,0) at the lower left corner of the display screen of No. 5, the celestial sphere (long radius Xc, long radius Xc, which is stereoscopically displayed around the point T (Xo, Yo) as a center. The following formula is used for coordinate conversion to the position P (X, Y) on the short radius Yc).

X = Xo + RP = Xo + Xpsinα = Xo + Xccosβ · sinα Y = Yo + TQ + QR = Yo + Xcsinβ + Ypcosα = Yo + Xcsinβ + Yccosβ · cosα However, Xp and Yp are loci when the celestial sphere is obtained from the point T as a long radius and an elliptic locus when viewed from a point T at an elevation radius β. The projection lengths on the major radius and the minor radius of the radius connecting the center point Q with the point P (X, Y) that envisions the center point Q at the azimuth angle α are RP = Xpsinα QR = Ypcosα.

If the GPS information display mode is selected, the satellite position information is first acquired by the GPS receiver 13 in step (101) of FIG. This satellite position information includes the satellite usage status, azimuth angle, and elevation angle, and the required data is acquired for all satellites that have captured the radio waves. Next, the azimuth angle, elevation angle, and altitude of the current location are calculated according to the distance to the satellite whose radio waves have been captured.

By the way, steps (101), (10
Since the azimuth angles of the satellite and the current position obtained in 2) are both absolute azimuths with true north as a reference, it is necessary to find the relative azimuth angle facing the satellite from the current position. Therefore, in the subsequent step (103), the azimuth angle of the satellite viewed from the current position, that is, the relative azimuth angle is obtained by subtraction from each absolute azimuth angle of the satellite and the current position. Then, the relative azimuth angle obtained here corresponds to the azimuth angle α used for the above-described coordinate conversion.

Next, the process proceeds to step (104) for determining the attribute of the display dot indicating the satellite position according to the position of the satellite on which the radio wave is captured on the celestial sphere. This step (104)
The detailed contents of the satellite are shown in Fig. 5. If the satellite position is ahead of the current position in the traveling direction, it is a small dot, if it is on the left and right in the traveling direction, it is a medium dot, and it is on the left and right in the traveling direction. For example, it is displayed with a large dot, and if it is in the front of the traveling direction, the brightness is reduced, if it is behind the traveling direction, the brightness is increased, and the display color is divided into green and gray depending on whether it is used for positioning. Different.

That is, first, in step (201), the satellite position is discriminated in any of the four regions according to the relative azimuth. Specifically, the four areas are areas ahead of the traveling direction (0 ° ≦ α ≦ 45 °, 315 ° ≦ α ≦ 360.
°) and the left and right areas in front of the traveling direction (45 ° <α ≤ 90
°, 270 ° ≤ α <315 °) and left and right regions behind the traveling direction (90 ° <α ≤ 135 °, 225 ° ≤ α <270
°) and the area behind the traveling direction (135 ° <α <225
4) areas, and when the belonging area is discriminated in step (201), step (30
1), (401), (501), and (601). In step (301), the size of the display dot is first designated as a small dot, and in the following step (302), it is determined whether or not it is a satellite used for positioning. Then, in the case of satellites used for positioning, dark green is designated in step (303), and in the case of satellites not used for positioning, dark gray is designated in step (304).

Similarly, in step (401), the size of the display dot is first designated as a medium dot, and the result of the determination in step (402) is received. In the case of the satellite used for positioning, step ( In 403), in the case of a satellite that is designated as dark green and is not used for positioning,
In step (404), a dark gray designation is received. Further, in step (501), the size of the display dot is first designated as a large dot, and the determination step (502)
For satellites used for positioning, follow step (5
In the case of a satellite which is designated as bright green in 03) and is not used for positioning, in step (504),
Received a light gray designation. In addition, step (60
In 1), first, the size of the display dot is designated as an extra large dot, and in the case of the satellite used for positioning following the determination step (602), in step (603), the bright green color is designated and positioning is performed. For unused satellites,
In step (604), a light gray designation is received.

When the attribute of the display dot is thus determined, the drawing position of the display dot is calculated according to the above formula in step (105) of FIG. This drawing operation is repeated every time the current position and the satellite position are known from the received radio waves while the navigation device 11 is actually used. Even if the route guidance mode is selected, the current position is displayed on the map near the current position on the screen. Operation unit 1
It will be performed without interruption as the work given to 2. Therefore, in the final determination step (106), steps (101) to (106) are continuously performed until it is determined that the navigation device 11 has stopped operating due to the power being turned off. Therefore, even if the satellite information display mode is suddenly switched during the route guidance mode, the receivable satellites can be immediately displayed on the stereoscopically displayed celestial sphere. Therefore, when the positioning accuracy deteriorates, the reason can be immediately understood at a glance from the screen switched to the satellite information display mode.

As described above, the navigation device 11
According to the above, the celestial sphere centering on the present location is not displayed two-dimensionally in the plane viewed from the position directly above the present location, but the altitude is known outside the latitude and longitude. The celestial sphere and satellite positions can be displayed stereoscopically, which makes it easier to visually recognize the satellite distribution and azimuth and elevation of individual satellites, and the direction of the satellites behind a building or tree. When deciding whether or not to be, it is possible to intuitively understand not only the relationship between the azimuth of the satellite and the heading, but also the elevation angle and altitude. Even if the satellite is hidden in one direction, it is possible to judge at a glance the magnitude relationship between the angle of looking up at the tip of the tree and the elevation angle of the satellite read from the screen, and whether or not dense trees cause reception failure. To understand intuitively Can.

In the above embodiment, the satellites that have captured the radio waves are displayed in dots by distinguishing the size and the brightness according to the position on the celestial sphere or the area to which they belong, and the display colors are displayed by distinguishing whether or not they are used for positioning. However, for example, as shown in FIG. 6, four types of display dots, which are a combination of two sizes of large and small and three types of brightness of large brightness, medium brightness, and small brightness, are assigned to the above-mentioned four areas, and positioning is performed. It is also possible to display the dots in different colors according to whether or not they are used. Also, FIG.
As shown in, for example, a celestial sphere displayed as a plane figure is divided into four equal parts, for example, satellites belonging to the front area are green, satellites belonging to the left and right areas are yellow, and satellites belonging to the back area are red. The display dots may be displayed separately and the size of the display dot may be changed according to whether or not the satellite is used for positioning.

[0023]

As described above, according to the present invention, a GPS receiver that receives radio waves from a plurality of satellites to position the current location, and the radio waves are received on a celestial sphere having a planar figure centered on the current location. Since the satellite position stereoscopic display means for stereoscopically displaying the position of the satellite is provided and configured, the two-dimensional positional relationship of the plurality of satellites is shown in the plane viewed from the position directly above the current position of the celestial sphere with the current position as the center. Instead of displaying it, the altitude can be known in addition to the latitude and longitude, and the satellite position can be stereoscopically displayed on the celestial sphere of the plane figure. Angles and elevations are easy to visually recognize, and when judging whether the direction of the satellite is behind a building or a tree, intuitive not only the relationship between the direction of the satellite and the heading but also the angle of elevation and altitude are intuitive. Can be grasped in , For example, if there are dense trees in the diagonal direction ahead and the satellites are hidden behind them, you can judge at a glance the magnitude relationship between the angle of looking up the tip of the tree and the elevation angle of the satellite read from the screen. However, it has an excellent effect that it is possible to intuitively understand whether or not dense trees cause reception failure.

Further, according to the present invention, the satellite position stereoscopic display means stereoscopically locates the position of the satellite specified by the azimuth and elevation on the orbit of a three-dimensional celestial sphere about the current position in a two-dimensional orthogonal coordinate system. Since an arithmetic unit for converting the coordinates into a position on the celestial sphere to be visually displayed and drawing and a display for displaying the satellite position drawn by the arithmetic unit together with the stereoscopically displayed celestial sphere are provided, The satellite displayed on the satellite orbit of the three-dimensional celestial sphere can be dot-displayed with the azimuth and elevation angles on the celestial sphere stereoscopically displayed in the two-dimensional Cartesian coordinate system suitable for display on the display. The route of radio waves connecting the current location and the satellite can be grasped three-dimensionally, which allows the surrounding environment to be seen in the actual field of view, that is, the skyscrapers surrounding the current location, dense trees, or elevated railway lines. And highways, etc. actually determined such whether cause radio failure, by matching against the display screen, the effects of the equal is intuitively possible.

Further, according to the present invention, the satellite position stereoscopic display means is an ellipse centered at the current location and having an elevation angle of zero degrees, a crossing line passing through the center of the ellipse and showing north, south, east and west, and intersecting the ellipse at the current location. On the celestial sphere, which is stereoscopically displayed with a plurality of orbital lines having different azimuth angles intersecting at the point directly above, the radio wave captured satellite is dot-displayed based on the azimuth angle and the elevation angle. Although the celestial sphere, which is a three-dimensional solid, is a two-dimensional figure, it can be displayed on the screen as a three-dimensional diagram that accurately captures the features of the three-dimensional object with depth, which allows the satellite displayed on the celestial sphere to be seen from the current location. The recognition of which direction and to what extent it is looking up has an excellent effect such as being able to obtain the feeling of catching the satellite with eyes.

Further, the satellite position stereoscopic display means displays the satellite captured by the radio wave in a dot display by distinguishing the size, the brightness or the color according to the magnitude of the relative azimuth angle with respect to the present location, or the satellite captured the radio wave is displayed. Since the dot display is made by distinguishing the size, the brightness, or the color depending on whether or not it is used for positioning, from the dot indicating the position of the satellite displayed in the two-dimensional orthogonal coordinate system, not only the position of the satellite, Read at a glance information such as whether the satellite is ahead or behind the direction of travel, whether it is on the left or right of the direction of travel, and whether it is used for positioning. This makes it possible to objectively and intuitively grasp the superiority and inferiority of the reception environment and the background thereof.

[Brief description of drawings]

FIG. 1 is a schematic block configuration diagram showing an embodiment of a navigation device of the present invention.

FIG. 2 is a diagram showing a relationship between a dot attribute for displaying a satellite position and a display area.

FIG. 3 is a diagram for explaining the principle of coordinate conversion by the computing unit shown in FIG.

FIG. 4 is a flowchart for explaining the operation of the navigation device shown in FIG.

5 is a flowchart showing an example of steps for determining the attribute of the display dot shown in FIG.

FIG. 6 is a diagram showing a modified example of a relationship between a dot attribute for displaying a satellite position and a display area.

FIG. 7 is a diagram showing another modified example of the relationship between the attribute of the dot displaying the satellite position and the display area.

FIG. 8 is a diagram showing an example of a display screen of a conventional navigation device.

FIG. 9 is a diagram showing another example of a display screen of a conventional navigation device.

[Explanation of symbols]

 11 navigation device 12 satellite position stereoscopic display means (calculator) 13 GPS receiver 14 key input device 15 satellite position stereoscopic display means (display) 16 map information storage medium

Claims (5)

[Claims] 1. A GPS receiver that receives radio waves from a plurality of satellites to measure the current position, and a satellite position that stereoscopically displays the position of the satellite that received the radio waves on a celestial sphere with a planar figure centered on the current position. A navigation device comprising a stereoscopic display means. 2. The satellite position stereoscopic display means stereoscopically displays the position of the satellite specified by the azimuth angle and the elevation angle on the orbit of a three-dimensional celestial sphere about the current position in a two-dimensional orthogonal coordinate system. The arithmetic unit for converting the coordinates into a position on the celestial sphere for drawing, and the display for displaying the satellite position drawn by the arithmetic unit together with the stereoscopically displayed celestial sphere. Navigation device. 3. The satellite position stereoscopic display means is orthogonal to the ellipse having a zero degree elevation angle centered on the present location in the two-dimensional Cartesian coordinate system, a cross line indicating north, south, east and west passing through the center of the ellipse, and the ellipse. The satellite which has captured a radio wave is displayed in dots on the celestial sphere which is stereoscopically displayed with a plurality of orbit lines having different azimuth angles intersecting at a point directly above the present location, based on the azimuth angle and the elevation angle. 1. The navigation device according to 1. 4. The satellite position stereoscopic display means displays dots of the radio wave-captured satellite by distinguishing the size, brightness, or color according to the relative azimuth angle with respect to the current location. The described navigation device. 5. The satellite position stereoscopic display means displays dots of the radio wave-captured satellites by distinguishing their size, brightness or color depending on whether or not they are used for positioning. The described navigation device.