Data processing: measuring – calibrating – or testing – Measurement system – Orientation or position
Reexamination Certificate
2000-09-28
2003-02-04
Hilten, John S. (Department: 2863)
Data processing: measuring, calibrating, or testing
Measurement system
Orientation or position
C702S152000, C342S357490
Reexamination Certificate
active
06516285
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field to which the Invention
The present invention relates to position detecting apparatus with DSRC feature and its control method, and in particular to a driving-support system in automobile applications.
2. Description of the Related Art
Conventional position detecting means using radio waves include a position detecting system using satellites and a position detecting system using communication base stations.
The former is a position detecting system using a scheme whereby radio waves are received from a plurality of satellites on a predetermined orbit and the current position of the user is obtained from the difference of the time required for radio waves to reach the Earth. Standalone technologies include the GPS (Global Positioning System) and the GLONASS (Global Navigation Satellite System).
The latter is a system whereby the approximate position of the user can be detected at the center of a telecommunications operator by determining which base station area the user is located through the use of densely installed communications base stations. The PHS (Personal Handyphone System) is one of such technologies currently in use.
In addition to the position detecting systems that use satellites, the DSRC (Dedicated Short Range Communication) technology is drawing people's attention and used for communication means etc., in the ETC (Electronic Toll Collection system) apparatus.
When wishing to mount a position detecting system using satellites and a DSRC system on car navigation apparatus, etc. at the same time, high costs and increased power consumption are major problems that prevent such an implementation.
In conventional car navigation apparatus, as shown in an example of
FIG. 11
, a GPS module
601
is mounted as position detecting means and a DSRC module
602
for ETC is mounted as a DSRC system, both interconnected with a navigation apparatus main unit
603
for displaying information to the driver. The GPS module is composed of an antenna section
604
for receiving GPS signals, an RF section
605
, and a GPS baseband processor
606
. The GPS baseband processor
606
uses a GPS signal preprocessor
608
for performing high-speed demodulation on RF input signals
607
that have been converted to the baseband bandwidth and uses a CPU
609
, a ROM
610
, a RAM
611
, an RTC (real-time clock)
612
, and a non-volatile RAM
613
dedicated for GPS for controlling the GPS signal preprocessor and process and save demodulated signals.
Meanwhile, the DSRC module
602
is composed of an antenna section
614
for receiving DSRC signals, an RF section
615
, and a DSRC baseband processor
616
. The DSRC baseband processor uses a DSRC signal preprocessor
618
for performing high-speed demodulation on RF input signals
617
that have been converted to the baseband bandwidth and uses a CPU
619
, a ROM
620
, a RAM
621
, a cipher processing circuit
622
, and a memory card
623
dedicated for DSRC for controlling the GPS signal preprocessor and process and save demodulated signals.
Power supply used is adapted, as shown in
FIG. 12
, to directly feed power to the GPS module
701
and the DSRC module
702
.
DSRC map data supply mechanism, as shown in
FIG. 13
, is composed of a geographical information DB (database)
803
that provides ROM geographical information
802
recorded on CD-ROMs, etc., depending on the search input
801
, position detecting apparatus
805
for outputting the current coordinate information
804
, a display data generation circuit
807
for inputting coordinate information and searching the geographical information DB to acquire RAM geographical information and to generate and output geographical display data
806
corresponding to the geographical display range on the monitor, and a monitor
808
for receiving and displaying the geographical display data.
Geographical data display operation using position detecting apparatus and with DSRC apparatus is executed according to the flowchart in FIG.
14
.
First, after display operation has started, in step S
901
, coordinate information is acquired from the GPS. Instep S
902
, display range is determined according to the coordinate information. In step S
903
, collation with the geographical information DB is made to determine whether a tollgate is present or not in the display range, and if any, in step S
904
, the tollgate coordinates and the toll are overlapped on the geographical image to generate display data. Otherwise, in step S
905
, the geographical image alone is displayed on the monitor as display data.
Next, activation of the DSRC section will be explained with reference to the flowchart in FIG.
15
.
Once the DSRC section is activated via starting the engine of a vehicle, the DSRC section is under permanent power feed. In step S
1002
, the carrier sense, or output to detect whether radio waves in a bandwidth to be received are present or not, is checked. In case no carriers are detected, execution is exited and DSRC baseband processing is terminated. Otherwise, DSRC signal processing is executed in step S
1004
.
However, providing separate communication circuits in the position detecting means and the DSRC means has a drawback that product costs and power consumption are too high.
SUMMARY OF THE INVENTION
The invention is proposed in view of the foregoing situation and aims at reducing power consumption and providing low-cost and compact position detecting apparatus with DSRC feature and its control method.
Position detecting apparatus with DSRC feature according to the first aspect of the invention comprises position detecting means for receiving radio waves for position detection and outputting position information and DSRC means for receiving radio waves for DSRC and processing signals, characterized in that the position detecting means and the DSRC means are controlled via the same CPU and share part or whole of storage means and that the position detecting means is adapted to operate in either the full drive mode or suppress mode.
Via such a configuration, the position detecting means is adapted to operate at least in the full drive mode and suppress mode so that both modes can be used without increasing the throughput of CPU, by normally driving the position detecting means in the full drive mode and using the suppress mode only when the DSRC means is used.
Position detecting apparatus with DSRC feature of the first aspect of the invention according to the second aspect of the invention is characterized in comprising timing signal generating means for determining the approach to a DSRC base station and driving the DSRC means as well as placing the position detecting means in the suppress mode.
Via such a configuration, in addition to the advantage of the first aspect of the invention, the approach to a DSRC base station position is determined, timing signals are generated, and the timing signals are used to place the position detecting means in the suppress mode. This allows position detection and DSRC to be performed more efficiently.
Position detecting apparatus with DSRC feature of the first or second aspect of the invention according to the third aspect of the invention is characterized in further comprising a geographical database and position-related information adding means that adds and saves anew onto the storage means information obtained via DSRC means and new DSRC base station position information.
Via such a configuration, in addition to the foregoing advantages, received information that is not found in the database can be easily added. Position-related information can be automatically added within apparatus. This eliminates the need for updating the database thus saving database update costs. The storage means may be separately provided to store DSRC base station position information or the information may be stored in storage means for GPS.
Position detecting apparatus with DSRC feature of the second aspect of the invention according to the fourth aspect of the invention is characterized in that the position detecting means is adapted to
Hagiwara Yasunori
Hori Satoshi
Miyazawa Hideo
Cherry Stephen J.
Hilten John S.
Matsushita Electric - Industrial Co., Ltd.
Pearne & Gordon LLP
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