Patent Application
20190072393
The disclosure relates to determining the global position coordinates of a motor vehicle.
An on board unit (OBU) is the part of the dedicated short range communications (DSRC) system that is installed in the moving vehicle. The on board equipment (OBE) contains other equipment in addition to the OBU, such as a human machine interface unit and other communication equipment for the car. The road side unit (RSU) is the part of the DSRC system that is installed on the side of the road. The road side equipment (RSE) contains the RSU in addition to other equipment to link the RSU to the backend network that may be hosted in the cloud.
The DSRC implementation of RSU standard does not require precise GPS time in order to function properly.
The present invention may use RSE as a local base station in a Real Time Kinematic (RTK) module in a DSRC system. After the GPS receiver in the RSE is able to get a fix, the fix information can be used as input to an RTK engine along the pre-known location of the RSE to calculate certain GPS system errors such as orbital inaccuracies and ionic sphere modeling. The RSU in turn may send output parameters from the RTK module over the DSRC channel to the OBU and then to the GPS receiver in the OBE. With the RTK errors or correction model delivered to the GPS receiver in the OBE, the GPS receiver may be able to achieve a lane-accurate position fix.
In one embodiment, the invention comprises on board equipment in a motor vehicle, including a DSRC radio receiving a calculated GPS position error from road side equipment. The calculated GPS position error is based upon a difference between a known position of the road side equipment and a position estimated by a first GPS receiver within the road side equipment. A second GPS receiver is communicatively coupled to the DSRC radio and estimates a position of the vehicle. The second GPS receiver adjusts the estimation of the vehicle position based upon the calculated GPS position errors and/or correction model done in the RSE.
In another embodiment, the invention comprises a global positioning method for a motor vehicle, including the following steps performed within the motor vehicle. A calculated GPS position errors and/or correction model is received from road side equipment. The calculated GPS position error is based upon a difference between a known position of the road side equipment and a position estimated by a first GPS receiver within the road side equipment. A global position of the motor vehicle is estimated. The estimation of the vehicle's global position is adjusted based upon the calculated GPS position error and/or correction model. The adjusted estimation of the vehicle's global position may be accurate within less than one meter.
In yet another embodiment, the invention comprises a global positioning arrangement for a motor vehicle. The arrangement includes on board equipment disposed within the motor vehicle and road side equipment. The road side equipment includes a first GPS receiver estimating a global position of the road side equipment. A module is communicatively coupled to the first GPS receiver and calculates a GPS position error based upon a difference between a known global position of the road side equipment and the global position of the road side equipment as estimated by the first GPS receiver. A first radio receives the calculated GPS position error from the module and wirelessly transmits the calculated GPS position error and or correction model. The on board equipment includes a second radio receiving the calculated GPS position error from the first radio. A second GPS receiver is communicatively coupled to the second radio and estimates a position of the vehicle. The on board equipment adjusts the estimation of the vehicle position based upon the calculated GPS position error or the correction model.
In a further embodiment, the invention comprises a global positioning arrangement for a motor vehicle. The arrangement includes road side equipment having a first GPS receiver estimating a position of the road side equipment. A module is communicatively coupled to the first GPS receiver and calculates a GPS position error based upon a difference between a known position of the road side equipment and the position of the road side equipment as estimated by the first GPS receiver. The module models at least one factor that caused the GPS position error. A first radio receives the at least one factor model from the module and wirelessly transmits the at least one factor model. On board equipment is disposed within the motor vehicle. The on board equipment includes a second radio receiving the at least one factor model from the first radio. A second GPS receiver is communicatively coupled to the second radio and estimates a position of the vehicle dependent upon the at least one factor model.
An advantage of the present invention is that it may, in OBE, reduce GPS position error from meters to lane-accurate (e.g., centimeters). This is very important for robust implementation of many safety apps in the connected industry.
A better understanding of the present invention will be had upon reference to the following description in conjunction with the accompanying drawings.
During use, RSE 12 has a pre-known position which was determined when RSE 12 was permanently and fixedly installed. This pre-known position may be communicated to RTK module 20. GPS receiver 18 may calculate a position and communicate this calculated position to RTK module 20. RTK module 20 may then calculate a GPS position error based on a difference between the GPS calculated position and the pre-known position of the RSE. RTK module 20 then may transmit the calculated GPS position error to DSRC radio 22. Next, DSRC radio 22 of RSE 12 may transmit the RTK calculated GPS position error over DSRC channel 16.
DSCR radio 24 of the OBU and OBE 14 may receive the RTK calculated GPS position error over DSRC channel 16. GPS receiver 26 may receive and use the RTK calculated GPS position error to correct and/or adjust its own calculated global position coordinates such that its adjusted global position coordinates are accurate to within less than one meter and thus the lane that the vehicle having ORE 14 is in can be reliably determined. More particularly, the error calculated between the calculated position of RSE 12 and the actual position of RSE 12 might not he used directly to correct the position calculation of OBE 14. Rather, the error calculated between the calculated position of RSE 12 and the actual position of RSE 12 may be used to model factors that caused the error, such as satellite orbital inaccuracies, local ionic sphere and perhaps other factors. Then these factor models may be used in, and applied to, the position calculation of OBE 14. The modeling of the errors may be performed in RSE 12 or in OBE 14.
Next, in step 204, a global position of the motor vehicle is estimated. For example, GPS receiver 26 may calculate its own calculated global position coordinates.
In a final step 206, the estimation of the vehicle's global position is adjusted based upon the calculated GPS position error. For example, GPS receiver 26 may receive and use the RTK calculated GPS position error to correct and/or adjust its own calculated global position coordinates.
The foregoing description may refer to “motor vehicle”, “automobile”, “automotive”, or similar expressions. It is to be understood that these terms are not intended to limit the invention to any particular type of transportation vehicle. Rather, the invention may be applied to any type of transportation vehicle whether traveling by air, water, or ground, such as airplanes, boats, etc.
The foregoing detailed description is given primarily for clearness of understanding and no unnecessary limitations are to be understood therefrom for modifications can be made by those skilled in the art upon reading this disclosure and may be made without departing from the spirit of the invention.
This application claims benefit of U.S. Provisional Application No. 62/554,116 filed on Sep. 5, 2017, which the disclosure of which is hereby incorporated by reference in its entirety for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| 62554116 | Sep 2017 | US |
