JPH03220411A - Navigation apparatus for vehicle - Google Patents

Abstract

PURPOSE:To improve the precision in position measurement and to facilitate current-position matching by providing a position measurement enabling time zone storage means of storing a time zone wherein a position measurement error is at a prescribed level or below, and a timer means and a current-position data storage means. CONSTITUTION:Based on a coefficient of a position measurement error computed on the basis of information sent from a position measuring satellite, a position measurement enabling time zone storage means stores a time zone wherein the position measurement error is at a prescribed level or below. When the time zone stored in the time zone storage means comes, a timer means starts a satellite information receiver automatically. A current-position data storage means stores and updates the current position data recognized by the satellite information receiver which is operated automatically by the timer means. Accordingly, proper measured position data are always stored automatically and therefore current position matching at the start of a satellite position measurement means can be executed with high precision.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a navigation device for a vehicle.

(Prior art) If we consider the current situation in which a driver is driving a car toward a destination, the driver navigates an unfamiliar land using a map 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 road signs and the scenery.

In other words, even today, when computers and data communications have developed and there is an overabundance of information, the essence of driving a car remains almost the same as it was when the car was invented.

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

The navigation system includes, for example, one that detects the horizontal component of the geomagnetic hector and uses it as an orientation parameter (hereinafter referred to as the geomagnetic method), and one that uses a gas rate gyro that uses the inertia of helium gas as an orientation sensor. (hereinafter referred to as inertial navigation method)
In addition to Nato, there are at least three circular orbit satellites (navigation satellites,
The GPSS method (Global
A method such as the Bonn/Yonning System with Kano Terite has been proposed.

Each of these navigation systems is equipped with a CD ROM and a CD player that store a large number of two-dimensional color map data as travel guide information for the vehicle, as well as a CD player for storing the destination to be reached. It has a destination setting means for setting a destination, a own vehicle position recognition means for recognizing the current position of the vehicle including the departure point, etc. It is configured to display two-dimensionally displayed map data as a color image on a CRT display (
For example, see Japanese Patent Application Laid-Open No. 62-209216).

When using such a navigation device, the driver follows the optimal driving route based on the map displayed moment by moment on the display screen of the CRT (driving along the optimal driving route while looking at the planned road). You will be able to reach your destination with peace of mind.Then, the vehicle position display mark that moves as you drive will be displayed as Ma, Puma,
The travel route is plotted and displayed on the CRT screen by means of ticking or the like.

By the way, in a navigation device for a vehicle such as the above-mentioned vehicle, first and foremost, high guidance accuracy is most important, not only because of cost issues. What basically determines the guidance accuracy is the vehicle position detection performance of the vehicle position recognition means. From that point of view, the three driving guidance methods mentioned above are currently the most promising.
It is based on the CPS5 method among the own military position detection methods.

In the case of the GPSS method, since it is possible to recognize the absolute position of the vehicle's own weight by receiving distance information and time information from multiple (as few as three) satellites, it does not require correction by other means. As such, it is possible to ensure a sufficiently high self-vehicle position detection ability (positioning error of about ±302).In addition, even if the vehicle is transported by sea as a ferry horde, the self-weight position can be determined again. I wonder if I need to reset the settings (this is convenient.

However, when accurately determining the position of the vehicle using the GPSS method as described above, altitude data of the vehicle's traveling position is originally required.

If there is no altitude take (altitude change data according to driving), only two-dimensional positioning data can be obtained, and there is a considerable error between the two-dimensionally measured travel distance and the actual travel distance. will occur. Therefore, when trying to perform three-dimensional positioning by obtaining altitude data as described above, the problem arises that the three navigation satellites mentioned above are not enough and a fourth navigation satellite is required for altitude measurement. . In other words, whether all the clocks on the three satellites are accurately synchronized (we know exactly whether they are ahead or behind), or whether the clock on the vehicle is inaccurate or not, and its progress is not accurate.・Since the delay is likely to be unknown, this means that four unknowns are required.

However, currently there are not enough navigation satellites launched into circular orbits around the Earth, and it is practically difficult to always secure four or more navigation satellites, and even if four
Even if it becomes possible to secure a set of navigation satellites, since the satellites are orbiting independently on their own, depending on the timing, the alignment between the satellites may be poor, and the signal from one of the satellites may not be received. There may also be a situation where reception becomes impossible and proper three-dimensional positioning becomes impossible.

In other words, depending on the relationship between the navigation satellites mentioned above and their scheduled flight times, there are times in the day when positioning is possible (Th) and times when positioning is not possible (Th), as shown in Figure 7.
(other than). Therefore, during the above-mentioned time period when positioning is impossible, the positioning error becomes large, and the positioning take (
In particular, altitude take) cannot be used (cannot be input into the current position data memory).

For this reason, for example, as seen in the invention described in Japanese Patent Application Laid-Open No. 63-26529, in the three-dimensional positioning system GPS type vehicle travel guidance device proposed so far, four or more By combining two positioning systems: a 3D positioning system using satellites and a 2D positioning/stem using 3 satellites, and installing a separate altimeter that does not use satellites, it is possible to achieve proper 3D positioning using 4 (18 satellites). If possible, navigation data such as the current position is detected and memorized using the 3D positioning/stem described above, but if proper 3D positioning is impossible due to overlapping satellites, the above 3 satellites that can be received are used. There is a system that employs a combination/stem configuration in which altitude information from the altimeter is incorporated into two-dimensional positioning data to form positioning data.

In addition, especially when an altimeter is not installed, it is possible to manually input the specified altitude data into the memory section in advance, or to update the altitude information sequentially using the latest 3D positioning data from previous trips. Other methods are being considered, such as storing the information in memory and reusing it as approximate data for future trips.

(Problem to be Solved by the Invention) However, as described above, the two-dimensional positioning system combined with an altimeter cannot take advantage of the advantages of the GPS system, and there is a problem in that accuracy decreases.

Also, manually setting altitude data according to the driving route is completely unacceptable to general users. Therefore, in consideration of such circumstances, it is reasonable to reuse the final altitude approximation data obtained from the above-mentioned travel as subsequent altitude data.

However, if this is done, a new problem arises as to how to obtain accurate altitude data in relation to the fluctuation of the positioning error coefficient as described above.

(Means for Solving the Problems) The present invention was made for the purpose of solving the above-mentioned problems.
In a vehicle equipped with a satellite receiver that receives time information and recognizes the current position of its own weight based on the information, positioning is performed based on a positioning error coefficient calculated based on information sent from the positioning satellite. a time zone storage means for storing a time zone in which the error is less than a predetermined level; a timer means for automatically starting the satellite/transmission device when a time zone that has been memorized by the time zone storage means; and the timer. The present invention is characterized by further comprising current position data storage means for storing and updating current position data recognized by the satellite receiving device which is automatically activated by the means.

(Function) In the configuration of the vehicle navigation device of the present invention,
A positioning error coefficient representing a positioning error level is detected, and a time period in which the positioning error coefficient is less than a predetermined value and the positioning accuracy is better than a predetermined level is stored in advance based on the relationship with the expected arrival time of the positioning satellite. Then, when the time slot reaches the specified time period, the timer means activates a satellite receiver, which is a satellite-based current position recognition means, to store and update the recognized current position data.

Therefore, according to this configuration, proper positioning data is always automatically stored, and current positioning can be performed with high precision when a new satellite positioning means is activated.

(Effects of the Invention) As a result of the above, according to the vehicle navigation device of the present invention, it is possible to provide a vehicle navigation device with high positioning accuracy and easy current positioning.

(Embodiment) FIGS. 2 to 7 show the structure and operation of a navigation device for a vehicle according to an embodiment of the present invention.

First, FIG. 2 shows the stem structure of the vehicle travel guidance system in the same embodiment, and the reference numeral IO is a navigation control unit that forms the center of the control unit, and the navigation control unit IO is as follows: A central information processing unit (hereinafter simply referred to as CPU) 11, a read-only memory (hereinafter referred to as
Random access memory (hereinafter simply referred to as RAM) 1 that stores various control data at any time (referred to as ROM) 12
3. It is composed of an interface circuit 14, etc., which inputs and outputs data between various external devices to be described later and the CPU 11.

So, the above navigation key 7yon control unit 10
The first external device that can be combined with this is a CD that stores travel guide information in the form of maps on multiple pages and at several scales.
- In-vehicle CD player 2 for reading map information and altitude data from ROM (compact read-only memory) 1, setting, changing, and resetting destinations;
An operation switch unit 3 that performs various operations such as changing the optimal route and displaying detailed map contents; a vehicle position recognition device 4 that detects the current vehicle position Pn; CRT display 6 in cluster section
A display control circuit 5 for displaying on the screen of
A video memory 7 or the like attached to the video memory 7 is provided.

CD player 1'2', t, drives the above-mentioned CD-ROMI, and reads map information of a desired predetermined area and altitude data corresponding to it from among the map information of all of Japan stored in the CD-ROMI. It is output according to the designated address (designated north, south, east, west), and is manually inputted to the above-mentioned CFull via the Tecoder 8 and the interface circuit 14. Each of the read information is temporarily stored in RA~113. The output of the CD player 2, which has been Tecoded via the Tecoder 8, is also output to the side of a normal in-vehicle audio device (AMP, equalizer, speaker, etc.) 9.

The above CD-ROMI is designed to store map information of about 30,000 color still images, and in the case of this embodiment, at least two scales (normal/enlarged) are available. In addition, the map information content (each vane map)
It is configured so that it can be enlarged or reduced in four stages (area level a, 1 to 4).

Next, the operation switch 3 is composed of, for example, a screen touch type, and includes (1) menu, (2) information, (3) reset, (4) enlargement, (5) reduction, (6) details, Various operation switches such as (7) correction, (8) altitude reading, etc. are provided. The ON output of the operation switch 3 is encoded by the Juncoder 16 and then sent to the interface circuit 14.
It is manually inputted to the CPU II via the CPU. The CPU II is
In response to the input from the operation switch 3, a predetermined calculation (program processing) is performed to operate the display control circuit 5 for driving the CRT, thereby displaying an image corresponding to the contents of the command.

Furthermore, the own military position recognition device 4 that recognizes the current position of the own vehicle
In the case of this embodiment, for example, as shown in FIG. It is composed of a combination of recognition means, and each output thereof is inputted to the CPU 11 via a switching circuit 20.

First, the first vehicle position recognition means 4A, as shown in FIG. 3, includes a vehicle speed sensor (wheel speed sensor) 42 that detects the vehicle speed (wheel fA), a geomagnetic sensor (orientation sensor) 41 consisting of a magnetic compass, It is comprised of a signal processing circuit 43 which receives detection signals from both sensors 42 and 41, detects the direction of movement of the vehicle and the relative distance from a reference value, and determines the current position of the vehicle. Further, the second own vehicle position recognition means 4B
For example, the global positioning satellite system (G
As shown in the figure, there is a ground main control station 76 that transmits radio waves from a ground station antenna 75, and at least four aircraft that each receive radio waves from the ground station antenna 75. Artificial navigation satellite (GPS satellite) 77A
77D and each of these satellites 77A to 77D, calculates a positioning error coefficient (GDOP value) indicating the degree of the geometric positioning error, and uses the positioning error coefficient data from the ground antenna 75. Monitor station 8 superimposed on radio waves
5, the GP receives radio waves from the four satellites 77A to 77D as shown in
Based on the reception timing between the radio waves received by the S receiver 44 and the GPS receiver 44, the four satellites 77A-
The signal processing circuit 45 detects the current position of the vehicle A by grasping the distance, altitude, and time between the 77D and the vehicle A, and also detects the positioning error coefficient due to the deterioration of radio waves, etc. lateral error coefficient detection f, stage 46.

The positioning error coefficient detection means 46 includes the GPS receiver 44
The positioning error coefficient value (GDOP) included in the entire received radio wave
: 0.1, 2.3) or above a predetermined value, and when the electric field strength (field strength D) is below a predetermined value (for example, when a vehicle is driving in a tunnel, etc.) (when unable to do so, etc.)
This outputs a positioning error increase signal. moreover,
The self-weight position recognition means 4 in FIG. 3 includes a switching circuit 20 that selectively switches between the geomagnetic type and the satellite-based vehicle position recognition means 4A and 4B. When the coefficient detection means 46 does not output the positioning error increase signal, the satellite-based second own vehicle position recognition means 4B is selected, while when the positioning error increase signal is output, -
selects the first port position recognition means 4A of the geomagnetic type and outputs the current self-weight position signal of the selected vehicle to the CPU II of the navigation control unit 10.

Further, reference numeral 60 indicates a timer that determines and sets the positioning available time period.

The navigation control unit 10 shown in FIG. Navigation control is performed to follow the route, and the optimal route in relation to the destination Po is displayed as shown in FIG. 5, for example.

That is, first, before starting operation,
, the above-mentioned CD-ROMI is loaded into the CD player 2, and the CD player 2 is driven. This makes it possible to read the map information (normal scale) of the optimal travel circuit set corresponding to the destination Po that the user is about to go to.

Next, proceed to step S, and by operating the operation switch 3, the objective tlI! Po
Set specifically.

Furthermore, in this state, the above-described own vehicle position recognition means 4 is operated to accurately determine the own vehicle position Ps including the altitude take () ().
Read tart (input to RAM).

Then, in the following step S3, the current vehicle position P5 is
Set the optimal route from tart to the set destination Po, and set the starting point P based on the optimal route.
The initial page 7 (\O1 map) from t is displayed on the screen of the CRT display 6 on the meter cluster side, and the own vehicle position mark NIP is plotted in a superimposed state on the map road on the screen. This is then updated sequentially as the vehicle progresses.

Next, the above-mentioned altitude take (H) rewriting operation by the above-mentioned navigation control unit 10 will be explained in detail with reference to the flowchart of FIG.

First, in Step S, for example, the appropriate positioning possible time period hs(N) to hr(,)(
4 times/day), reset the empty value N of the timer T to N=O (VJ period setting).

Next, the process proceeds to step S, where the current GPS receiver 44 is
It is determined whether or not the power supply is not an ACC (Vcc) power supply but a 1,000B state, that is, a hacked-up state (non-starting state).

As a result, if it is determined as YES, the process proceeds to step S3, and the set count value of the timer T (positioning available time period T
Set value for counting h) Ns in step S If
~S 24 and set to the set value N s (N 5 = N), while if the determination is No, step S 12
- Step 8 moves to perform positioning possible time zone setting operation in the normal navigation control state.

Next, when the setting operation of N=Ns in step S3 is completed, it is determined in step S4 whether or not the current timer count value N is greater than 0, that is, the count of the timer T (
Only after determining whether or not decrement) has been completed does the process proceed to step S, where it is determined whether the current time has reached the start time hs (,) of the positioning available time zone shown in Fig. 7 above. do. If the answer is YES, indicating that the positioning possible time hs(N) has been reached, the process proceeds to the following step S.
The main power supply (Vcc) of the PS receiver 44 is turned on to start receiving positioning information from the GPS navigation satellites 77A to 77D.

On the other hand, in the case of NO, where the above-mentioned positioning possible time hs (v) has not yet been reached, the count setting value N of the above-mentioned timer T is set.
is decremented for one cycle (BN=N-1).

On the other hand, as in step S above, the GPS receiver 44
When the receiving operation starts, altitude data (H) is then obtained from the distance information and time information from the GPS navigation satellites 77A to 77D.

Then, the process further advances to step S8 to determine whether the current time has reached the end time hE(N) of the positioning possible time zone Th in FIG. 7. If YES, the above positioning operation is ended and step Proceed to S.

In step S8, it is determined whether proper altitude data Hn has actually been obtained through the positioning operation. Then, if YES that appropriate review data Hn has been obtained, step
Go to block S1゜ and read the above altitude data memory (RAM).
The altitude data Hn-, in the middle is replaced with the newly obtained altitude data Hn.

Then, after decrementing the set count value N to N-t (step S), the step S described above is performed.
Return to step 4 and repeat the above operation (step.

Repeat steps S4 to S, 1).

On the other hand, when appropriate altitude data Hn cannot be obtained,
From step S9, go straight to step S.

Jump to 1.

As a result of the above, in the case of this example, the positioning possible time period T h=
Since the altitude data in the altitude data memory 60 is updated only when the appropriate altitude data H is obtained between hs(1,I) and hE(s), the positioning accuracy is improved and the reliability of the navigation function is improved. Sexuality will greatly improve.

Moreover, since the above altitude data is updated by a timer control means that automatically controls the operation according to the positioning possible time period Th determined in advance by the position of the satellite array used in orbit, the current position can be easily determined. becomes easier.

By the way, the altitude data H (H
The determination and storage control of the positioning available time period Th necessary for updating n) is performed as follows.

That is, first, in step S11, the operation is started on the condition that, for example, the vehicle has started traveling.

Then, first in step S If, the GPS navigation satellite 77
Determine whether or not A to 77D and the GPS receiver 44 are in a receiving state, and if they are in a receiving state, step S1
Proceed to step 4 to update the satellite data.

Then, in step S I S+ S I 6, N=0.
After performing each reset of t=o, further step S1
Proceed to step 7. In step S+7, it is determined whether or not reception of four or more GPS navigation satellites can be expected at the time t, and if YES, the process proceeds to step S III and the upper step S1 sets N to N=N. -1 (proceed to step S19 and set the positioning available time hs(s) to h
Set s(v)=t. And then step S
After proceeding to to and setting t=tJ-Δt, the following step S
7. Then again at time 1 (1 = 1 + Δt) 4 or more GPs
Determine whether reception of the S navigation satellite can be expected.

If the result is YES, step and switch until the result is No.
,. , S, 1, and when the result is No, the process proceeds to step StZ and the positioning possible time zone end time hE(
, ) to fllt at that time (hE(+1)=
1) Do. Then, in step S23, it is determined whether the above-mentioned time t has reached 24:00, which is the end time of the measurement day, and the above-mentioned operation is continued until then. And YE
When it becomes S, N5 is set to H and the process returns to step S (step S, 4).

On the other hand, if reception of four or more GPS navigation satellites determined as No in step S is not expected, proceed to step StS and change the time t to 1=1+Δt, and then perform the measurement in step S. The progress of the day is repeatedly determined.

[Brief explanation of drawings]

Fig. 1 is a claim correspondence diagram 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 steering wheel position recognition device of Fig. 2. 4 is an explanatory diagram showing the recognition principle of the self-weight position recognition device, and FIG. 5 shows the basic navigation control unit operation in the configuration shown in FIG. 2. Flowchart, Figure 6 is a flowchart showing the current position recognition operation (altitude data history new operation) in 3D side position, Figure 7 is the flowchart showing the current position recognition operation at the time of 3D side position (altitude data history new operation), Figure 7 is the l
This is a flight schedule map of F+. l...CDROM 2...CD player 3...Operation switch 4...Vehicle position recognition device 6...CRT display unit 10...Navigation key 7 control unit 11...
...CPU 41...Geomagnetic sensor 42...Wheel speed sensor 4.1...CPS receiver 60...Timer 77A-77D -Navigation satellite Figure 1

Claims (1)

[Claims] 1. In a vehicle equipped with a satellite receiving device that receives distance information, time information, etc. from multiple positioning satellites and recognizes the current position of the vehicle based on the information, the information sent from the positioning satellites a time zone storage means for storing a time zone in which the positioning error is below a predetermined level based on a positioning error coefficient calculated based on the positioning error coefficient; 1. A navigation device for a vehicle, comprising: a timer means for activating the timer means; and a current position data storage means for storing and updating current position data recognized by the satellite receiving device automatically activated by the timer means.