(a) Field of the Invention
The invention relates to an electronic device, particularly to a road side data exchange device.
(b) Description of the Related Art
The global positioning system (GPS) has been extensively used in daily life and the most commonly seen application is a vehicular positioning device for planning and navigating the destination and promoting traffic safety, etc. However, GPS cannot have positioning 100% precisely yet and have an error of about 10˜15 meters without using calibration.
In order to perform more precisely satellite-based positioning, a calibration signal from a differential GPS should be received to do calibration. Reference stations are set and are used to acquire calibration values of the GPS positions so as to effectively calibrate errors caused by satellite electronic clocks, ephemeris, ionosphere and troposphere. However, the error caused by multipath still cannot be effectively improved. When a user is far away from the reference station, the differences of the terrain, weather or ionosphere data at which the user and the reference station are located are the major factors to cause the calibration result away from the expected value. Besides, the cost of setting up reference stations for the differential GPS is high and reference stations usually are set up in the spacious or boundless areas having few barriers, such as mountain or suburban areas to collect more complete satellite data.
In the differential GPS, after the server collects and compiles the data of each reference station, a user should acquire the real-time calibration data through a mobile network. However, since the city having larger traffic flow usually is farther away from the location where the reference station is set up, the difference of the satellite calibration data is larger and the vehicular positioning system cannot acquire the calibration value of its environment and only has the limited calibration result. Besides, when the vehicular positioning system acquires the calibration data, the calibration data needs to be downloaded from the server through a 3G network and the cost of the network connection is needed. If there are many users downloading at the same time, the server may be overloaded to cause a service problem.
One object of the invention is to provide a road side data exchange device for providing a data exchange mechanism to exchange data between road side data exchange devices so as to promote the positioning precision of a vehicular positioning device.
An embodiment of the invention provides a road side data exchange net. The road side data exchange net includes a plurality of road side data exchange devices, disposed on neighboring roadsides separately. The road side data exchange device includes a positioning system for receiving satellite data regularly or periodically; a calculator for calculating a calibration value of the satellite data to generate an analyzed result data; and a database for storing the analyzed result data. Each of the road side data exchange device broadcasts the analyzed result data from its database to all of neighboring road side data exchange devices to supply the analyzed result data to an electronic device.
Another embodiment of the invention provides a method of road side data exchange. The method includes the following steps. At first, a plurality of road side data exchange devices are provided separately on road sides to exchange satellite calibration data to form a road side data exchange net. Then, an electronic device is provided to search the nearest road side data exchange device. Communication with the nearest road side data exchange device is performed via a preset communication protocol to acquire the satellite calibration data. A satellite positioning data is calibrated according to the satellite calibration data. Then, satellite positioning is performed according the calibrated satellite positioning data.
The embodiments of the invention provide a road side data exchange net and a method of road side data exchange. The road side data exchange devices disposed in the city can receive the observation data of GPS and the road side data exchange devices can be further connected in a net to exchange data through wireless transmission. The positioning device communicates with the road side data exchange devices through a dedicated short range communication (DSRC) protocol to acquire a calibration value suitable for that area so as to spare the cost of connecting to a mobile network for acquiring the calibration data from the server. Besides, the satellite positioning precision can be increased.
Other objects and advantages of the invention can be better understood from the technical characteristics disclosed by the invention. In order to clarify the above mentioned and other objects and advantages of the invention, examples accompanying with figures are provided and described in details in the following.
As shown in
In an embodiment, the electronic device may use a dedicated short range communication (DSRC) protocol to communicate with the road side data exchange devices. The invention is not limited to this example. Any current or future to-be-developed communication method may be used in communication of the present invention. In addition, the electronic device of this embodiment may be any mobile positioning device, such as onboard unit (OBU) in a vehicular, or any portable positioning device, etc. It should be noted that the number and types of road side data exchange devices are not limited to the above example and can be adjusted according to actual needs.
The road side data exchange device 210 includes a global positioning system (GPS) 213, a calculator 212 and a database 211. The GPS 213 receives satellite data regularly or periodically. The calculator 212 calculates a calibration value of the satellite data to generate an analyzed result data Ar. In an embodiment, the analyzed result data Ar may be a GPS error calibration value. The database 211 stores the analyzed result data Ar. Each of the road side data exchange devices 210 broadcasts the analyzed result data Ar from its database 211 to the database 211′ of all of neighboring road side data exchange devices 210′ to exchange data with the other road side data exchange devices so as to form a data exchange net.
As shown in
In an embodiment, the electronic device 300 may be disposed in a vehicle. In another embodiment, the electronic device 300 may be a portable device or a vehicular device. When the electronic device 300 is a vehicular device, the communication device 301 may be an onboard unit (OBU). The onboard unit may use a dedicated short range communication (DSRC) protocol to communicate with at least one road side data exchange device 210.
By the above method, the electronic device 300 may communicate with the road side data exchange net of the invention to acquire a precise GPS signal to have a better satellite positioning effect.
In an embodiment, as shown in
Although the present invention has been fully described by the above embodiments, the embodiments should not constitute the limitation of the scope of the invention. Various modifications or changes can be made by those who are skilled in the art without deviating from the spirit of the invention. Any embodiment or claim of the present invention does not need to reach all the disclosed objects, advantages, and uniqueness of the invention. Besides, the abstract and the title are only used for assisting the search of the patent documentation and should not be construed as any limitation on the implementation range of the invention.
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101111225 A | Mar 2012 | TW | national |
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Number | Date | Country | |
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