JPH03226623A - Navigation apparatus for vehicle - Google Patents

Abstract

PURPOSE:To display the current position of a vehicle stably by displaying the current position after performing map matching based on the absolute positional data by a satellite navigation system when the current position is not displayed within the probability circle. CONSTITUTION:The information of a predetermined area stored in a CD-ROM 1 is output to a CD (compact disk) player 2 and input to a CPU 11 through a decoder 8 and an interface circuit 14. An ON output from an operating switch 3 is, through an encoder 16 and the circuit 14, input to the CPU 11. The CPU 11 executes a predetermined operation in response to the input from the switch 3, so that an image is displayed at 6 through a display control circuit 5. Moreover, in a position recognizing circuit 4, the position of one's own vehicle which is recognized through the presuming navigation method and satellite navigation system is selectively input to the CPU 11 through a switching circuit. If the current position of the vehicle is not displayed within the probability circle, a navigation control unit 10 performs map matching on the basis of the data of the absolute position obtained by the satellite navigation system, and the current position of the vehicle is displayed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a napi game 7-I device for a vehicle.

(Prior art) For example, if we consider a situation in which a driver is driving a car toward a destination, the driver navigates an unfamiliar land using maps and roads in a lonely space isolated from the outside world. It can be said that I am in a state of simply stepping on the accelerator toward my intended destination, relying only on my senses and the scenery. In other words, even today, when combi coaters and data communications have developed and there is an overabundance of information, the essence of driving a car has hardly changed from when the car was first invented.

In view of these circumstances, the development of vehicle travel guidance devices generally referred to as navigation systems has recently become active.

The navigation system includes, for example, a direction sensor that detects the horizontal component of the geomagnetic vector and uses it as a direction parameter (hereinafter referred to as a geomagnetic method), or a gas rate gyro that uses the inertia of helium gas. The so-called dead reckoning/stem system uses three or four circular orbit satellites (referred to as C and PS navigation satellites) to detect the direction (hereinafter referred to as the inertial navigation method). So-called satellite navigation systems have been proposed, such as the GPSS system (Global Posi/Yoninog/Stem with Satellite), which allows accurate detection of the vehicle's position anywhere on the earth.

By the way, in such a navigation system for a vehicle, the most important thing is not only the cost but also the high guidance accuracy. What basically determines the guidance accuracy is the steering wheel position detection performance of the first stage of own vehicle position recognition. Therefore, the view is 1. ) Is the two types of sailing mentioned above currently considered the most promising based on l? This is the satellite navigation/stem based on the above-mentioned GPS S system that uses artificial satellites.

In the case of the satellite navigation system, the absolute position of the vehicle in two or three dimensions is recognized by receiving distance information and time information from a plurality of (at least three, preferably four or more) satellites. Therefore, there is an advantage that a sufficiently high self-vehicle position detection ability (positioning error of about ±30+e) can be ensured without particularly requiring correction by other means. Furthermore, even if the vehicle is transported by sea on a ferry boat or the like, there is no need to reset the port position, which is convenient.

However, at present, there are not enough navigation satellites launched in circular orbits around the earth, and it is difficult in practice to always secure a desirable number of four or more navigation satellites. Even if navigation satellites can be maintained at &V, since the satellites are orbiting on their own, depending on the timing, the alignment between each satellite may be poor, and the signal from one of the satellites may be lost. Deafness may also occur, where reception becomes impossible and proper three-dimensional positioning becomes impossible.

That is, as shown in FIG. 9, the navigation satellite described above has a time period (Th) in which positioning is possible and a time period (other than Th) in which positioning is not possible. Therefore, during the above-mentioned time period in which positioning is not possible, the positioning error becomes large, and the positioning data during that period cannot be used.

For this reason, conventionally, for example, Japanese Patent Application Laid-Open No. 632652
As seen in the invention described in Publication No. 9, two positioning systems are combined: a three-dimensional positioning/stem using a satellite and a two-dimensional positioning system using dead reckoning using the above-mentioned direction sensor, and the latter two-dimensional positioning system is combined. A map matching means is provided for the system, and accurate navigation data such as the current position is detected using the appropriate 3D positioning system using four or more satellites, the 1111th position, or the above 3D positioning/stem when possible. When proper 3D positioning is impossible due to poor satellite position or satellite alignment, dead reckoning is performed, and the 2D positioning data from the ``!l:/ stem is corrected based on the relationship with road network data. Some employ multiple/stem configurations to produce the most accurate port position indication data possible.

(Problem to be Solved by the Invention) However, even if map matching is performed by the map matching means as described above, it is inevitable that a certain amount of error will occur in the detection and display of the current position by the dead reckoning system. As a result, there are cases where unreasonable map matching is performed, and the resulting display is undeniably unreliable.

However, when considering a system using only dead reckoning navigation, it is impossible to judge and recognize the reliability (accuracy) of the display state (display position). On the other hand, in the three-dimensional positioning system using the above satellite data, it is possible to detect a positioning error coefficient indicating the degree of positioning error, and it is possible to judge the accuracy of the C positioning data. Therefore, in a navigation system equipped with both dead reckoning/stem and satellite navigation/stem as described above, satellite data is used according to the accuracy range determined based on the level value of the positioning error coefficient of the satellite data. It is desirable to be able to stably display the current position by appropriately using map matching using dead reckoning navigation.

(Means for Solving the Problems) The present invention was made for the purpose of solving the above problems, and includes a satellite navigation/stem that recognizes the absolute position of a vehicle based on information from a satellite, and a direction A vehicle comprising: a dead reckoning navigation/stem for calculating the estimated position of the vehicle based on the distance traveled; and a manobuma means for matching the above-mentioned estimation i++ navigation/stem in relation to actual route network data. In the navigation device for 79, there is a 1lt11 position error detection means for detecting the level of positioning error in the satellite navigation/stem; A machine that determines whether the vehicle's current position is displayed within the circle or whether it is a fortune-telling, Pumanoting accuracy judgment 1
If the vehicle's current position is not displayed within the circle, map matching is performed based on the absolute position data from the satellite navigation/stem to display the vehicle's current position. This is a characteristic feature.

(Function) In the configuration of the vehicle navigation 7 device of the present invention,
First, a positioning error level detection means detects the level of positioning error in the satellite navigation system, and the current position of the vehicle is determined within a certain radius of 1,000 yen, the size of which is determined according to the level of positioning error detected by the positioning rule difference level detection means. A map matching accuracy determination means is provided for determining whether or not the vehicle current position is displayed within the probability circle, and if the display error is greater than a predetermined value, the original dead reckoning navigation/ Instead of map matching based on the positioning data of the stem, we use reasonable map matching within the range of the above probability circle based on the absolute position positioning data from the satellite navigation/stem to calculate the vehicle's current position without feeling strange (
It is designed to be displayed.

Therefore, in dead reckoning, even in cases where the positioning error is large and deviates from the probability circle mentioned above, the extreme skip display caused by performing map matching using the positioning data obtained by dead reckoning is eliminated, and the positioning data obtained by dead reckoning is as accurate as possible based on satellite data. Based on accurate positioning data, it becomes possible to make appropriate corrections with small changes in position.

(Effects of the Invention) As a result of the above, according to the vehicle navigation device of the present invention, the display of the current vehicle position is always stable.

(Embodiment) FIGS. 2 to 8 show the configuration and operation of a vehicle navigation device according to an embodiment of the present invention.

First of all, FIG. 2 shows the stem structure of the vehicle navigation device in the same embodiment. Reference numeral 10 indicates a navigation control unit that forms the center of the control unit. NotoIO is equipped with a central information processing unit (hereinafter simply referred to as CPU) +1 read-only memory with a built-in control program (
(hereinafter referred to as ROM) 12, a random access memory (hereinafter simply referred to as RAM) 13 that stores various control data at any time, various external devices to be described later, and the above CPL'11.
It is composed of an inter-fnis circuit 14, etc., which inputs and outputs data between the terminal and the terminal.

And the above-mentioned Navigation Key/Yon Control Uninote 10
As an external device to be combined with the above-described one, first, there is an in-vehicle device for reading out map information from a CD-ROM (compact disk type read-only memory) 1, which stores a large number of driving guide information in the above-mentioned map format at a plurality of scales. For C
D player 2, operation switch unit 3 for performing various operations such as setting, changing, and resetting destinations, changing optimal routes, and displaying detailed map contents; current vehicle position P1 (X n, Y
a display control circuit 5 which inputs the image signal output from the CPU 11 and displays it on the screen of, for example, a CRT display 6 in the meter cluster section; A video memory 7 and the like are provided.

The CD-player 2 drives the CD-ROMI and transmits information on a desired area out of map information for all of Japan stored on the CD-ROMI to a designated address (longitude X and latitude Y). and the above CPIJ via the decoder 8 and the interface circuit 14.
11.

The read information is temporarily stored in the RAM 13. The output of the CD player 2 decoded via the decoder 8 is a normal in-vehicle audio device (A M
P, equalizer, speaker, etc.) is also output to the 9 side.

The above-mentioned CD-ROMI is designed to store, for example, map information of about 30,000 color still images, and in the case of this embodiment, map information of at least two types of scales (normal/enlarged) is stored. Provided.

Next, the operation switch 3 is composed of, for example, a screen touch type, and includes (1) menu, (2) information, and (3)
Reset, (4) Enlarge, (5) Reduce, (6) Details, (7)
There is also a control switch for models such as ShuiL. The ON output of the operation switch 3 is encoded by the encoder/coder 16 and then sent to the CP via the interface circuit 14.
It is input to L111. The CPU II performs a predetermined calculation (program processing) in response to the input from the operation switch 3 and operates the display control circuit 5 for driving the CRT.
An image corresponding to the above command contents is displayed.

Furthermore, a vehicle position recognition device 4 that recognizes the current vehicle position.
In the case of this embodiment, for example, as shown in FIG.
It is constructed by combining two different sets of own force position recognition means 4B, A and the second own force position recognition means 4B using GPS satellite navigation described above, and their respective outputs are sent via a switching circuit 20. It is designed to be selectively input to CPji II.

First, the first vehicle position recognition means 4A includes a geomagnetic sensor 41 that detects the geomagnetism, such as a flux gate, as shown in FIG. ) and a wheel speed sensor 42 that detects the vehicle's traveling direction (azimuth θ) and a predetermined reference point P based on the outputs from both these sensors 41 and 42.
5tart: Detect the relative side @(l from P o (Xo, Yo) and find the current position of the vehicle P n (X n, Y
n) (the recognition mechanism will be described later, see FIG. 4) 43.

In other words, if at least the exact traveling route 1lli and the traveling direction θ of the vehicle are known, the relative positional relationship between the two points from point a to point an can be easily known. If the starting point P5tart=Po(Xo, Yo) is known (set at the time of start), then the position an of the running vehicle can be known.

For example, Figure 4 shows the basic principle.
Assuming that we are traveling from a known starting point a1 to a point an, a certain distance (about 5 m) al-a,, ay'a
3. 83'a4q aa'a5+ as'ags
as'a7q al-a8, as-aes as
~an(unit movement distance a between each point, (t !+
13...In is determined from the output of the wheel speed sensor 42) Each time the vehicle travels, the geomagnetic sensor 41 calculates the change in the traveling direction θ and performs coordinate transformation, and calculates the east-west and north-south points between the two points. distance Δx= 1 cosθ and Δy
= 1 sin θ are calculated, and the values are sequentially added. As a result, the vehicle position at point an (Pn)
will be identified.

Further, the second own vehicle position recognition means 4B utilizes a global positioning satellite/stem (GPSS) as shown in FIG. 5, for example, and as shown in FIG.
A main control station 76 on the ground that transmits radio waves from the ground station antenna 75, and a small number (at least 4 (preferably 18)) of artificial navigation satellites (G P
S satellites) 77A to 77D, and each of these satellites 77A to 77D
77D, calculates the positioning error coefficient GDOP value indicating the degree of positioning error of the 4 waves, and calculates the positioning error coefficient GDOP.
For the ground station system equipped with a monitor station 85 that superimposes the value on the radio waves transmitted from the ground station antenna 75, the four GPS
G receiving each transmission radio wave from M law satellites 77A to 77D
Based on the reception timing between each satellite radio wave received by the PS receiver 44 and the GPS receiver 44, the distance, altitude, and time between the four satellites 77A to 77D and the vehicle A are ascertained. a second signal processing circuit 45 on the satellite navigation system side that absolutely detects the current position P11 of the vehicle A, and positioning error coefficient determining means that specifically determines the level of the positioning error coefficient GDOP value of the satellite radio wave. (circuit) 46. The positioning error coefficient determining means (circuit) 46 determines the entire '' received by the GPS receiver 44:
4 When the GDOP value included in the satellite is below a predetermined value due to poor satellite alignment, and when the strength of the 74 waves (electric field strength) itself is below a predetermined value (for example, when a vehicle is running in a tunnel) This outputs a positioning error determination signal when radio waves cannot be received, etc. The positioning error determination signal is divided into, for example, four stages 0.1.2.3 and output depending on the degree of the positioning error. The positioning error 111 constant signal indicates that the positioning error power is 4-larger as the value lj-larger.

Further, the switching circuit 20 switches the satellite-based second own vehicle position recognition means ( Satellite navigation/stem) 4B is selected, while when the positioning error judgment value 2 and 3 signals are output (large error), the first military position recognition means using geomagnetism (dead reckoning navigation system) 4A is selected. The current position signal of the selected vehicle is output to the CPU II of the navigation unit 10.

By the way, when displaying the above-mentioned own military position, although the size can be increased or decreased depending on the accuracy of the positioning method used, errors associated with positioning are unavoidable, and errors accumulate especially in dead reckoning, so the self-weight There is a possibility that the current location of the vehicle may gradually shift from the road on which the vehicle is being driven and be displayed on the wrong road.

The vehicle navigation system of this embodiment uses so-called map matching, which corrects the current position of your vehicle by drawing it to the road where your vehicle is most likely to be traveling among the roads near your own army. This is performed as necessary, such as every predetermined distance traveled or every predetermined time, thereby correcting positional deviations as needed and preventing the above-mentioned errors from accumulating. Then, in order to perform this map matching, restore all the roads near your army and create a candidate list.
In addition to memorizing this information, as the vehicle travels, it evaluates the possibility of driving on each road to determine whether or not its own troops are traveling on that road. The map matching means for performing the evaluation has a /stem configuration as shown in FIG. 1 and is incorporated in the CPU II. In addition, road traffic data necessary for this purpose is stored in the RAM 13. While the switching means is in use, the switching circuit 20 shown in FIG. 3 inputs both outputs of the first signal processing circuit 43 and the second signal processing circuit 45 to the CPU II. According to the stacking range determined according to the judgment value 01.2.3 of the positioning error coefficient judgment means 46, each positioning data is effectively used properly to perform a stable map matching display. .

The navigation control unit 10 shown in FIG. Navigation control is performed to always follow the optimal route, and the selection of the optimal route in relation to the destination P end and the display of the own military position Pn are performed, for example, as shown in FIG. That is, first, before starting the operation, in step S, the above-mentioned CD-ROM is
Load it into the D player 2 and drive the CD player 2. As a result, map information (normal scale) of the optimal driving route is set corresponding to the destination P end that you are about to go to.
or becomes readable.

Next, the process proceeds to step S, and by operating the operation switch 3, the destination P end to which the user is about to go is specifically set.

Furthermore, in this state, the above-mentioned own force position recognition device 4 is activated to determine the accurate own vehicle position P o (X o
, Y o) (input into RAM).

Then, in the continuation (step S), the above current vehicle position P5
Set an optimal route from P o (X o, Y o) to the set destination P end, and initial base from the starting point PO based on the optimal route; (N
The O3 map is displayed on the screen of the CRT display 6 on the meter cluster side, and the map and the map are displayed on the screen corresponding to the detected positions detected by the own vehicle position recognition devices 4A and 4B. , and print the own vehicle position mark MP in a superimposed manner by making full use of the marking means. This is then updated sequentially as the vehicle progresses.

Next, we will explain in detail the combination unit control operation according to the positioning error level between the GPS satellite navigation system, the dead reckoning system, and the map matching/stem using the navigation/yeon control unit 10 by referring to the flowchart in FIG. explain.

First, in step S1, the current values (two-dimensional coordinates) Xo, "j'o" of the starting point Po (see FIGS. 4 and 8) are input.

Then, in step S, it is determined whether the vehicle has actually started traveling. As a result, if it is determined to be YES (travel start), the current direction θ of the vehicle detected by the second vehicle position recognition means 4B is inputted, and furthermore, the moving distance l is calculated in step S4.

Then, the process proceeds to step S5, and from the traveling direction θ manually calculated in step S3 and the traveling route @ (traveling distance) 1 calculated in step S, the movement point is determined in the same manner as in the case of FIG. 4 described above. Calculate the position of P , (X ++ Y ,).

After that, the process proceeds to step S6, where the moving point P, (
It is determined whether there is road network data for the area corresponding to (X,, Y+). As a result, Y
If ES (exists), proceed to Step S7 and compare it with the road data to approximate the two-dimensional position (corrected position) P =
Calculate (X 2 + Y t). On the other hand, if there is no road data with No in step S6, step S
Proceed to l& and leave the above estimated positions X,, Y as they are.
+Y, substitute.

Next, the process advances to step S8. This station is ugly.

Then, it is determined whether the GPS navigation satellites are in a positioning deaf state where they can be properly received, and then the process proceeds to step S, where the positioning error level GDOP value (0 , 1, 2, 3) is calculated (see Figure 8).

The radius L that determines the size for the probability (r1 month or above GDO
It is determined according to the level of P value 0.1, 2.3 (for example, 1'
When o, L=30+n, when 1, L=lO○m, when 2, L
= 200m, L = 300m at 3).

After that, go through 8 more steps, x=pX c>
Calculate '-(Y 2 Y c)'' to find the value of IN for deviation from the probability centers Xc and YC in Figure 8 (
However, X, , Yc; the own vehicle position based on the positioning data obtained by the second own vehicle position recognition means 4Bi). Then, compare the value of I with the above value, and determine if L>x(YES)
If P 2 (X t, y-) is inside the probability radius of Then, find the two-dimensional seat collars X and Y for map matching. On the other hand, if L≦&(No), P, (Xf+ y
Step sr if t) is outside the probability of radius
Proceeding to step s, two-dimensional position values X and Y for map matching are determined based on the satellite positioning data xc and yc of the second self-army position recognition means 4B.

As a result, if L<1, where the value in Figure 8 g is outside the radius probability range, use satellite positioning data instead of dead reckoning/map matching that involves extreme displacement by stem. As a result, map matching of an appropriate amount of displacement is performed, and the current vehicle position can be displayed stably and without any discomfort.

[Brief explanation of drawings]

Fig. 1 is a diagram corresponding to the claims of the vehicle navigation device of the present invention, Fig. 2 is a block diagram showing the overall system configuration of the device, and Fig. 3 is the position of the own vehicle in Fig. 2. FIG. 4 is a block diagram showing the internal configuration of the recognition device; FIG. 4 is an explanatory diagram showing the recognition principle of the first own force position recognition means in the same own force position recognition device; FIG. FIG. 6 is a flowchart showing the operation of the basic navigation control unit in the configuration shown in FIG. 2, and FIG. Flowchart showing current position recognition and display operation using motion, FIG. 8 is an explanatory diagram showing map-matching operation of the flowchart in FIG. 7, and FIG. 9 shows satellite status within -day (24 hours). This is a forecast map of the satellite flight. 1...CD-ROM 2...CD player 3...Operation switch 4...To the slot position recognition device 4...First slot position recognition means-x B...・Second military position recognition means 6...CR
T-display 10...Nahike-7 Yono control Uni-noto 11.
...Cl) L 41...Geomagnetic sensor 42...Wheel speed sensor 44...GPS receivers 77A to 77D/Navigation satellite applicant Tsuta Co., Ltd. agent

Claims (1)

[Claims] 1. A satellite navigation system that recognizes the absolute position of the vehicle based on information from satellites, a dead reckoning system that calculates the estimated position of the vehicle based on the direction and distance traveled, and an actual dead reckoning system for the above dead navigation system. A vehicle navigation device comprising a map matching means for performing matching in relation to road network data, a positioning error level detecting means for detecting the level of positioning error in the satellite navigation system, map matching accuracy determination means for determining whether the current vehicle position is displayed within a probability circle with a predetermined radius determined according to the detected positioning error level; A vehicle navigation device characterized in that, if the vehicle is not located, map matching is performed based on absolute position data from the satellite navigation system to display the vehicle's current position.