JPH06130144A - Navigation system - Google Patents

Abstract

PURPOSE:To quicken rising in provision of navigational information. CONSTITUTION:The navigation system 11 comprises a GPS receiver 12 for receiving navigation radio waves from a plurality of GPS satellites 18 and measuring its own position, a CD-ROM unit 13 for recording map information and other relevant information in a CD-ROM to configure a map data base, a display/operating unit 14 including an LCD 14b and the like, and a controller 15 comprising a CPU and recording/working areas thereof, i.e., ROM, RAM 15b, a clock 15a, a common power supply therefor, i.e., a backup battery 15c, and a microprocessor controlling the entire system. The navigation system further comprises a fixed ground station 17 receiving navigation radio wave from the GPS satellite 18 and constantly updating the navigation data to keep a newest data, and a radio unit 16 for communication with the fixed ground station which takes in newest navigation data by radio from the fixed ground station 17 at higher data transmission rate than the GPS satellite 18 when the data collected from the GPS satellite 18 is inappropriate.

Description

Detailed Description of the Invention

[0001]

The present invention relates to GPS (Global Positio).
ning System Global Positioning System) related to a navigation device having a GPS receiver for receiving navigation radio waves from an artificial satellite to measure the current position of a moving body such as an automobile,
In particular, the present invention relates to a navigation device that speeds up the start of providing navigation information.

[0002]

2. Description of the Related Art Conventionally, as an example of a vehicle-mounted navigation device equipped with this type of GPS receiver, one shown in FIG. 3 is known. The navigation device 1 includes a controller 2 that controls the entire system, a display / operation unit 3 that is under the control of the controller 2, a CD-ROM unit 4 that stores map data and associated data. And a GPS receiver 5.

The display / operation unit 3 has operation buttons 3a,
A display device 3b such as an LCD (liquid crystal display) for displaying the own vehicle position on a map is provided, and the display device 3b is adapted to display the own vehicle position (current position of the own vehicle) mark 3c.

The GPS receiver 5 receives navigation radio waves from 3 to 4 GPS satellites and calculates the position of the vehicle based on the navigation data of the navigation radio waves, for example, in latitude, longitude and height.

The controller 2 is a CD-ROM
The map data is read from the unit 4 and the vehicle position data is read from the GPS receiver 5, and the vehicle position mark 3c is displayed on the display device 3b together with the road map. Further, when the operation button 3a is operated, it is possible to enlarge or reduce the map being displayed, and to use a database (for example, a tourist spot guide etc.) attached to the map. It is designed to provide navigation information necessary for driving.

When the GPS receiver 5 measures the position of the vehicle, the navigation data is processed according to the flowchart shown in FIG. 4, for example, and G is measured before the positioning is started.
It is necessary to collect and retain the navigation schedule of PS satellites (hereinafter referred to as almanac data) and the detailed orbit data of GPS satellites (hereinafter referred to as ephemeris data).

Further, it is necessary to prepare in advance the date and time of the vehicle position measurement and the approximate position of the vehicle position. Usually, the date and time are provided by the clock 2a of the controller 2. In addition, since the error of the approximate position of the own vehicle is usually within a range of several hundred km, the driver should select the map to be displayed as the current location, and the latitude and longitude of the center of the selected map should be the outline of the own vehicle position. It is used as position data.

Then, the almanac data and the ephemeris data of the navigation data once obtained are stored in the satellite data RAM 2b of the GPS receiver 5 or the controller 2 and retained by the backup battery 2c even when the power of the device is turned off. ing.

[0009]

However, in such a conventional navigation device 1, when the navigation device 1 is started up for the first time, or when the stored navigation data becomes old, or the backup battery 2c is exhausted, the R
When the data in the AM 2b disappears, the navigation radio waves broadcast from GPS satellites are received again by the GPS receiver to collect and retain the navigation data.

However, this received navigation data is shown in FIG.
It has a large amount of data and GP
Since the data transmission rate of the S satellite is as low as 50 baud, for example, 10 is required to receive all the received data.
It's taking a few minutes.

Also regarding the date and time, if an error occurs in the clock 2a of the controller 2 due to the exhaustion of the backup battery 2c, the vehicle position is determined based on the incorrect time. It costs. Alternatively, the positioning becomes impossible. For this reason, there is a problem that even if, for example, an automobile departs during that time, the navigation information may not be provided for, for example, ten minutes or more.

Therefore, the present invention has been made in consideration of such circumstances, and an object thereof is to provide a navigation device capable of accelerating the start-up of a GPS receiver and accelerating the start-up of providing navigation information. It is in.

[0013]

The present invention is configured as follows in order to solve the above-mentioned problems.

That is, according to the present invention, the GP is mounted on a moving body.
Receiving a navigation radio wave from the S satellite and receiving the navigation radio wave from the GPS satellite, and a vehicle position measuring means for determining the current position of the moving body based on the navigation data and self-held time data. In a navigation device having a ground fixed station for storing the latest data of the navigation data, when positioning the own vehicle position by the own vehicle position positioning means, the navigation data obtained from the GPS satellite by the own vehicle position positioning means And a determination means for determining whether or not the time data is appropriate, and when the determination means determines that the time data is not appropriate, data corresponding to the inappropriate data is sent from the ground fixed station to the GPS satellite. And a wireless device which takes in data at a higher speed than the data transmission speed and gives it to the vehicle position measuring means.

[0015]

[Operation] The own vehicle position positioning means measures the arrival time of a radio wave including time data indicating radio wave transmission time, navigation data such as almanac data, ephemeris data, and the like by positioning its own vehicle position, At the time of the positioning, whether or not the navigation data and the self-maintained (timekeeping) time data held by the vehicle position measuring means are appropriate, that is, the clock held by the vehicle position measuring means itself. Is determined by the determining means whether the almanac data or the ephemeris data is old data to be updated.

When it is judged by this judging means that at least a part of the navigation data is not appropriate, the data corresponding to the inappropriate data, for example, accurate time data is fetched from the ground fixed station by radio communication and the own vehicle is fetched. The position of the own vehicle is measured by giving it to the position measuring means.

Therefore, according to the present invention, the data necessary for positioning the own vehicle is taken in from the ground fixed station whose data transmission speed is higher than that of the GPS satellite, so that the data collection can be speeded up. As a result, it is possible to speed up the vehicle position measurement and speed up the provision of navigation information.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the overall construction of an embodiment of the present invention. In the figure, a navigation device 1 is shown.
1 is for a vehicle mounted on a moving body such as an automobile, and GP
It has an S receiver 12, a CD-ROM (read-only compact disk memory), a CD-ROM unit 13 for recording map information and related information to form a map database, and a plurality of operation buttons 14a. A display / operation device 14 having an operation section and an LCD (liquid crystal display device) 14b, a CPU and R as a storage and work area thereof.
OM, RAM15b, clock 15a and RAM15b
With a backup battery 15c that is a common power source of
A controller 15 including a microprocessor or the like for controlling the entire system; a ground fixed station communication radio 16;
It has a ground fixed station 17.

The GPS receiver 12 has a plurality of Gs (not shown).
It is a vehicle position locating means for receiving navigation radio waves transmitted from the PS satellites 18, 18 ... To the ground via an antenna and positioning the vehicle position (current position of the vehicle).

In other words, the GPS receiver 12 is a GP that incorporates a highly accurate clock such as an atomic oscillator such as cesium.
The radio wave transmission time and the orbit information of the earth's orbit are received from the S satellite 18 as navigation radio waves, and the arrival time of the radio waves is measured by the clock 15
The distance between the receivers is detected by measuring with a. Further, when the distance from one GPS satellite 18 is known, the receiving point, that is, the position of the own vehicle is present on any of the spherical surfaces centering on the GPS satellite 18.

Therefore, by receiving similar navigation data from, for example, three GPS satellite data, the intersection of each spherical surface can be set as the receiving position, that is, the own vehicle position, and the current position can be measured by three-dimensional coordinates. can do. The most important feature of this navigation is that the position of the vehicle can be located anywhere in the world.

However, in this navigation, as shown in FIG. 4, a plurality of GPS satellites 18, 1 required for positioning are used.
The almanac data of 8 ..., the approximate position of the vehicle position, and the date and time of positioning must be collected and held in advance.

Therefore, if the pre-stored almanac data is older than, for example, a half-year valid period, or if the ephemeris data is older than, for example, a few-hour valid period, these data are collected from the GPS satellites 18. There is a need.

The built-in clock 15a as described above
When there is an error in the time data, the positioning of the vehicle position based on this error takes a very long time or the positioning cannot be performed.

Therefore, there is a method of receiving and collecting the data necessary for positioning the own vehicle position from the GPS satellites 18. In that case, the data is time data indicating the radio wave transmission time as shown in FIG. , Ephemeris data of the GPS satellites 18 and almanac data of the GPS satellites 18, and in order to receive all the almanac data of all the GPS satellites 18, the data transmission rate of the GPS satellites 18 is, for example, 50 baud. Therefore, for example, it takes 10 minutes or more. In other words, it takes 10 minutes for the navigation device 11 to start after turning on the power switch,
During that time, no navigation information can be provided.

Therefore, in such a case, the controller 15 transmits the navigation data to G according to the program shown in FIG.
It is designed to be received wirelessly from the ground fixed station 17 rather than from the PS satellite 18.

The ground fixed station 17 constantly receives navigation radio waves from the GPS satellites 18, constantly updates the navigation data, and always stores the latest data. The ground fixed station communication radio 16 requests navigation data. When the signal was wireless,
Data transmission speed is faster than GPS satellite 18, eg 2
It is designed to transmit the latest navigation data at 400 baud.

FIG. 2 shows a flow chart of the program of the controller 15 when the navigation data is fetched from the ground fixed station 17 by the ground fixed station communication radio 16 as described above. This program will be described below.
In the figure, S10 to S21 indicate each step of the flowchart.

First, in S10, the navigation device 11
When the power switch is turned on, the controller 15 determines in S11 whether the built-in clock 15a is accurate. The clock 15a, as shown in FIG.
The backup battery 15c is shared by the RAM 15b that stores the navigation data from S8. Therefore, due to the consumption of the backup battery 15c, the timepiece 15
When an error occurs in a, it is considered that a malfunction occurs in the RAM 15b at the same time.
By checking whether or not the data in the predetermined area is normal, it is possible to determine whether or not the timepiece 15a is normal.

When it is determined in S11 that the timepiece 15a is normal, the process proceeds to S12, and when it is determined that there is an abnormality, the process proceeds to S13. If the clock 15a has an error, as described above, it takes a very long time to determine the position of the vehicle, or the position cannot be determined.

Therefore, in S13, the ground fixed station communication radio 16 is automatically activated, and in S14, the time data,
The almanac data and the ephemeris data are requested to the ground fixed station 17 and captured at the data transmission speed of the GPS satellite 18, for example, 2400 baud, which is higher than 50 baud. Then, in S15, the acquired data is downloaded to the GPS receiver 12, and in S16, the vehicle position is measured.

Since the time data stored in the ground fixed station 17 is accurate and the almanac data and the ephemeris data are the latest data, the position of the own vehicle can be accurately and quickly determined.

On the other hand, in S12, it is determined whether or not the almanac data is in the RAM 15b, and if there is, it is determined whether or not the almanac data has passed the valid period of, for example, half a year, and it is within the valid period. If so, the process proceeds to S17, and if NO, the process proceeds to S18.

At S18, the terrestrial fixed station communication radio 16
Is automatically activated, and in S19, the almanac data and the ephemeris data are wirelessly requested to the ground fixed station 17, and the data are wirelessly fetched from here to the GPS receiver 12 in S15. It is downloaded and the vehicle position is measured in S16.

Further, in S17, it is determined whether or not the ephemeris data is data within the valid period of, for example, several hours. If YES, that is, if the data is within the valid period,
At S15, the time data of the normal clock 15a and the almanac data and the ephemeris data within the valid period are
Data is loaded to the GPS receiver 12, and the position of the vehicle is measured in S16.

On the other hand, if the ephemeris data exceeds the valid time in S17, the ground fixed station communication radio 16 is activated in S20, and the ephemeris data is wirelessly requested to the ground fixed station 17 in S21. In addition, this data is taken in and given to the GPS receiver 12 in S15, S
At 16, the vehicle position is measured. After starting the positioning operation of the own vehicle position in S16, if the positioning is not completed within the predetermined time in 2 of S16, the process returns to S13 again, and the following steps for starting the ground fixed station communication radio 16 in S13 are performed. repeat.

Therefore, according to the present embodiment, even when the data necessary for positioning the vehicle position has an error or is old, such as when the navigation device 11 is started,
The own vehicle position is accurately and quickly measured, and the own vehicle position is displayed on the map displayed on the display device 14 as shown in FIG.
4c can be displayed.

Moreover, since the data necessary for positioning the own vehicle position is fetched from the ground fixed station 17 having a higher data transmission rate than the GPS satellite 18, the navigation device 11
The start-up of can be accelerated.

However, in this embodiment, the navigation device 1
However, the present invention is not limited to the time of activation of No. 1 and can be appropriately applied even after the activation.

Further, as the ground fixed station 17, the GP
A GPS data service institution that constantly collects navigation data at a location sufficient for S satellite 18 observation and provides these navigation data through wireless communication, etc. upon request, or GPS.
There is a head office of a vehicle operation management system that collectively manages position information of vehicles such as trucks obtained by a receiver at a business office of the head office. Such a ground fixed station can calculate the error in the distance from the GPS satellite, which is generated as a result of the positioning, from the navigation data based on the known position. Therefore, if this error is used as a correction value in the positioning calculation by the GPS receiver on the vehicle side, the positioning accuracy is improved (Differentiation
al GPS).

In normal use, high positioning accuracy is not always required. Therefore, in order to improve the positioning accuracy, in a vehicle operation management system that performs business use, such as monitoring the location of a car or managing work such as work, for a certain period of time, when the vehicle starts or ends, or when the headquarters inquires. In the above, the parameter necessary for positioning the own vehicle position may be automatically transmitted to the head office via the wireless device.

In general use, important route points are set along the drive route,
Alternatively, when the vehicle approaches the set point, the GPS service organization may automatically request the parameter via the radio to give the parameter.

Further, the ground fixed station communication radio 16
The wireless line between the ground fixed station 17 and the ground fixed station 17 has a low operating cost for commercial use and is used for normal business such as MCA (Multi-Channe).
lAccess) system, or the wireless line of the teleterminal system can be used.

Furthermore, this navigation device 11
It is sufficient to use a wireless line intermittently, so a next-generation cordless phone (in the UK, as a telepoint in the UK, is considered to be a service for car phones (cell phones) or near buildings such as station buildings and public institutions in the future. A method of accessing a public communication network such as (starting practical use) may be adopted, and according to this, the configuration can be relatively inexpensive.

[0046]

As described above, according to the present invention, the navigation data necessary for positioning the vehicle position at the time of start-up can be provided as necessary.
Since the data is collected from the ground fixed station, which has a higher data transmission rate than that from the GPS satellites, by radio, it is possible to speed up the start of providing navigation information.

[Brief description of drawings]

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

FIG. 2 is a flowchart of a processing program of the controller shown in FIG.

FIG. 3 is a block diagram showing a configuration of a conventional navigation device.

FIG. 4 is a flowchart showing a general procedure for positioning a vehicle position by a GPS receiver.

FIG. 5 is a diagram showing a general configuration of navigation data.

[Explanation of symbols]

 11 Navigation Device 12 GPS Receiver 13 CD-ROM Unit 14 Display / Operation Device 14a Operation Button 14b LCD (Liquid Crystal Display Device) 14c Own Vehicle Mark 15 Controller 15a Clock 15b Satellite Data RAM 15c Backup Battery 16 Ground Station Fixed Radio 17 Ground Station 18 GPS Satellite

Claims (1)

[Claims] 1. A vehicle position locating means which is mounted on a mobile unit, receives navigation radio waves from GPS satellites, and obtains the current position of the mobile unit based on the navigation data and self-maintained time data, In a navigation device having a ground fixed station for receiving the navigation radio wave from a GPS satellite and storing the latest data of the navigation data, the own vehicle position is measured when the own vehicle position is measured by the own vehicle position measuring means. Judgment means for judging whether or not the navigation data and the time data obtained from the GPS satellite by the positioning means are appropriate, and data corresponding to the inappropriate data when the determination means judges that the navigation data and the time data are not appropriate. A radio device that takes in from the ground fixed station at a higher speed than the data transmission speed of the GPS satellites and gives it to the own vehicle position measuring means. Characteristic navigation device.