JP2006275904A - Position locating system and vehicle-mounted device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a position locating system and a vehicle-mounted device capable of solving the conventional problem which should be overcome to improve their precision in the future, by improving the absolute position precision of a movable body from current tens of meter level to tens of centimeter to several meter level. <P>SOLUTION: The position locating system is provided with a lane marker 13 for reflecting electric waves emitted from the movable body, beacons 11, 12 for sending positional information, representing the position where the lane marker 13 is set and the vehicle-mounted device 14 mounted on the moving body. The vehicle-mounted device 14 is provided with a position detection means for detecting the position of the moving body relative to the lane marker 13, a positional information acquisition means for acquiring the positional information of the lane marker 13 sent from the beacons 11, 12 and a position-locating means for locating the position of the moving body according to the position of the moving body calculated, based on the position of the moving body relative to the lane marker 13 and the positional information of the lane marker 13. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a position locating system and an in-vehicle device for detecting a current position of a mobile object, particularly an automobile, with high accuracy.

  About 20 years ago, a location technology that realized route guidance services for car navigation systems was put into practical use. Since then, the number of car navigation systems has been widespread, with the cumulative total now being 17 million, with one installed in four. A position locating system in a car navigation system is composed of GPS (global positioning system) positioning, differential correction, inertial navigation (direction sensor + vehicle speed sensor), map, and map matching.

  FIG. 10 shows an outline of a position location system in a car navigation apparatus. In FIG. 10, the positioning system includes a GPS satellite 121, a reference station 122, a GPS correction site (such as the Internet) 123 as an infrastructure, and an in-vehicle device 124 includes a GPS positioning device 125, an orientation sensor, and a vehicle speed sensor. Inertial navigation positioning device 126 and the like.

  Next, a conventional location system will be described from the infrastructure side. More than 24 GPS satellites 121 orbit about 20,000 km above the earth, and transmit the time of the atomic clock and the position of the satellite. The signal from the GPS satellite 121 is also received by the electronic reference point which is the reference station 122, and the difference between the position calculated at the electronic reference point and the electronic reference point is transmitted as a correction signal to the GPS correction site 123. Yes. The GPS correction site 123 calculates the correction data of the vehicle from the correction data of the three reference points closest to the vehicle based on the position information obtained from the GPS positioning provided by the vehicle, and returns the correction data to the vehicle. The vehicle performs correction based on this correction data. This is called Virtual Reference Station (VRS) correction among the differential corrections.

  Next, the in-vehicle device 124 side will be described. The vehicle is equipped with a positioning device 125 using a GPS positioning method, a positioning device 126 using inertial navigation, and two types of positioning devices. The GPS positioning device 125 calculates the position of the vehicle from signals from four or more GPS satellites 121. In order to improve the accuracy of the calculated absolute position information (for example, 35 ° north latitude and 135 ° east longitude), the simplified version of the above-described differential correction (the reference stations 122 are installed at eight locations in Japan, and the correction data is FM The absolute position is corrected by multiplex broadcasting.

  The inertial navigation positioning device 126 includes an azimuth sensor that detects the traveling direction of the vehicle and a vehicle speed sensor that detects the traveling distance. Therefore, the current vehicle position is calculated by calculating the direction by the azimuth sensor and the distance by the vehicle speed sensor based on the position of the vehicle measured last time. Because of the principle of inertial navigation, the position error of the vehicle accumulates in proportion to the distance traveled and the time traveled (for example, a position error exceeding 10 m may occur every 1 km traveled). Correction is performed to reset the accumulated error from time to time based on absolute position information.

  However, in urban areas and the like, it is difficult to capture four or more GPS satellites 121, and positioning is performed only by inertial navigation for a long time until absolute position information is obtained by GPS positioning. It is often several tens of meters. Further, map matching is a technique for specifying a traveling route based on a road on a map, and is not a technique for improving the accuracy. For this reason, the position locating device used in the current car navigation system is at a level that can identify the travel path but cannot identify the travel lane.

As another technique, a system that embeds a lane marker on a road and detects the traveling position of the vehicle with high accuracy has been proposed. However, even if the relative position of the vehicle with respect to the lane marker can be detected, the absolute position is detected. (See, for example, Patent Document 1).

As described above, with the conventional position location system, it is possible to perform position location to the extent that an absolute position accuracy of several tens of meters and a route guidance service are realized.
Satoru Handa and two others, “Lane Marker System”, Matsushita Technical Journal Vol.47 No.5 Oct. (2001)

  In the conventional location system, the accuracy to realize the route guidance service of the car navigation device has been achieved, but the level to achieve the accuracy such as the detection of the driving lane used in the driving support service that is assumed in the future There is a situation that is far from. The reason for this is that only GPS absolute position correction corrects the accumulated error due to inertial navigation, and GPS satellites cannot be captured sufficiently in urban areas.

  The present invention provides a position locating system and an in-vehicle device that can improve the absolute position accuracy of a moving body from the current level of several tens of meters to a level of several tens of centimeters to several meters, for example, and solve the problem of future high accuracy. The purpose is to do.

  The position locating system of the present invention is a position locating system for locating the position of a moving body, and includes lane markers that reflect radio waves emitted from the moving body, and position information indicating positions where the lane markers are installed. A roadside device for transmission and a vehicle-mounted device mounted on the mobile body, the vehicle-mounted device detecting a position of the mobile body with respect to the lane marker, and a lane marker transmitted from the roadside device. Position information acquisition means for acquiring position information, and position positioning means for determining the position of the moving body based on the position of the moving body with respect to the lane marker and the position of the moving body calculated based on the position information of the lane marker. .

  The in-vehicle device of the present invention is mounted on a moving body, based on a signal from a lane marker that reflects radio waves emitted from the moving body and a roadside device that transmits position information indicating a position where the lane marker is installed. An in-vehicle device for locating the position of the moving body, a position detecting means for detecting the position of the moving body with respect to the lane marker, and a position information acquiring means for acquiring position information of the lane marker transmitted from the roadside device; Locating means for locating the position of the moving body based on the position of the moving body calculated based on the position of the moving body with respect to the lane marker and the position information of the lane marker.

  According to the present invention, by positioning the position of the moving body based on the position of the moving body with respect to the lane marker and the position of the moving body based on the position information of the lane marker, even in an urban area where GPS satellites cannot be sufficiently captured, for example, several Position positioning with high accuracy of 10 cm to several meters is possible, and services such as driving support systems can be provided.

  FIG. 1 shows the configuration of the position location system of this embodiment. In FIG. 1, the GPS satellite, GPS correction signal, and inertial navigation are the same as those shown in FIG. The newly added component for the embodiment of the present invention is a radio beacon 11 that communicates the position information of the lane marker 13 by quasi-microwave as a roadside device, or an optical beacon 12 that communicates the position information of the lane marker 13 by infrared rays. There is a lane marker 13 that reflects a radio wave at a frequency twice that of a transmission wave, for example, by a medium-long wave or ultrasonic wave type, which is embedded in a road. The in-vehicle device 14 has a function of obtaining position information of the lane marker 13 from a roadside device such as the radio wave beacon 11 or the optical beacon 12, a function of calculating the position from the lane marker 13, and the like.

  FIG. 2 is a schematic diagram of the radio wave beacon 11 and the optical beacon 12 installed in the vicinity of the road and the radio wave type lane marker 13 embedded in the road. Radio wave beacons 11 have already been installed at about 3,000 locations mainly on expressways, and traffic congestion information and radio wave beacon position information are transmitted to a substantially circular service area with a diameter of about 70 m by quasi-microwaves. Optical beacons 12 have already been installed at approximately 42,000 units (about 26,000 locations for each lane in the gantry 15) centering on general roads, with a roughly circular service area of approximately 3.5m in diameter. Infrared traffic information and optical beacon location information are transmitted.

  FIG. 3 shows a schematic configuration diagram of the in-vehicle device 14 and the radio wave type lane marker 13. The in-vehicle device 14 includes a transmission unit 35 that generates a 220 kHz radio wave emitted to the lane marker 13, a transmission antenna 34 that emits the 220 kHz radio wave generated by the transmission unit 35 toward the lane marker 13, and 440 kHz reflected from the lane marker 13. A detector 31 composed of three receiving antennas for receiving the radio wave, a receiver 32 for amplifying a 440 kHz received wave received by the detector 31, and a position detector 36 for detecting the position of the lane marker 13. .

  On the other hand, the lane marker 13 is a passive multiple reflection type radio wave lane marker. The lane marker 13 receives a 220 kHz radio wave emitted from the transmission antenna 34 of the in-vehicle device 14, and receives a 220 kHz signal received by the reception antenna unit 5 at 440 kHz. A frequency conversion unit 37 that converts the signal to 440 kHz, a transmission antenna unit 8 that transmits the converted 440 kHz signal to the in-vehicle device 14, and a case 9.

  As a feature of the system composed of the lane marker 13 and the in-vehicle device 14, the lane marker 13 does not require a battery, can be given information by phase identification, and the antenna installation height is mostly 20 to 50 cm from the vehicle lower surface. It can be installed in any vehicle or bumper, and it can operate normally even when the vehicle is stopped or slow. In addition, since the detector of the in-vehicle device 14 operates with a radio wave output within the weak wireless standard, an application for radio wave use on the vehicle side is unnecessary and low power consumption.

  Further, since the position of the reflected wave from the lane marker 13 is calculated by the ratio of two or more antenna inputs, the vehicle side can accurately calculate the distance from the lane marker 13. By having these characteristics, it is possible to realize high-accuracy lateral position detection accuracy.

  FIG. 4 is a block diagram showing a schematic configuration of the in-vehicle device 14 of the present embodiment. The in-vehicle device 14 includes a GPS positioning unit 61 that receives a GPS signal from a GPS satellite 65 and performs GPS positioning, an inertial navigation positioning unit 62 that measures the current position of the vehicle using an azimuth sensor and a vehicle speed sensor, and a radio beacon 11 or light. The lane marker position acquisition unit 63 that acquires the position information of the lane marker 13 from the beacon 12 and the current position of the vehicle measured by the inertial navigation positioning unit 62 are obtained as a positioning result by the GPS positioning unit 61 or a relative position between the vehicle and the lane marker 13. A vehicle position locating unit 64 that corrects the position based on the positioning result and locates the current position of the vehicle.

  Further, the in-vehicle device 14 includes a transmission antenna 34, reception antennas 43 to 45 that constitute the detector 31, a transmission amplifier 51 and an oscillation circuit 56 that constitute the transmission unit 35, and reception amplifiers 52 to 52 that constitute the reception unit 32. 54 and detection circuits 57 to 59, a phase difference detection unit 55 constituting the position detection unit 36, and a relative position calculation unit 60 that calculates a relative position between the vehicle and the lane marker 13.

  In FIG. 4, the oscillation circuit 56 oscillates a signal having a frequency of 220 kHz and outputs the output to the transmission amplifier 51 for transmission to the lane marker 13. The transmission antenna 34 is a substantially annular or substantially rectangular loop antenna. The receiving antennas 43 to 45 are antennas for receiving a transmission wave having a frequency of 440 kHz from the lane marker 13. The reception amplifiers 52 to 54 are amplifiers for amplifying the reception signals. The detection circuits 57 to 59 detect the amplified signals amplified by the reception amplifiers 52 to 54 and output them to the relative position calculation unit 60. In FIG. 4, three systems of receiving circuits are provided, and are arranged on the left, center and right of the bumper of the vehicle. The phase difference detector 55 detects the phase difference between the transmission radio wave and the reception radio wave.

  Next, the operation of the in-vehicle device 14 will be described. The transmission antenna 34 transmits a radio wave having a frequency of 220 kHz to the lane marker 13 as a continuous wave. The receiving antennas 43 to 45 are arranged on both sides and the center of the bumper of the vehicle, and are tuned with respect to the frequency of 440 kHz from the lane marker 13, and are reflected from the lane marker 13 when the vehicle passes near the lane marker 13. The received radio wave having a frequency of 440 kHz is received and amplified. The signals detected by the detection circuits 57 to 59 are output to the relative position calculation unit 60. In addition, the phase difference detector 55 performs a phase comparison between the transmission radio wave and the reception radio wave, and outputs the result to the relative position calculation unit 60. The relative position calculation unit 60 calculates the relative position of the vehicle with respect to the lane marker 13 by comparing the electric field strength of the radio waves received by the three receiving antennas 43 to 45.

  FIG. 5 shows the structure of the radio wave type lane marker 13. In FIG. 5, 5 is a receiving antenna of ferrite and coil, 6 is a frequency multiplication circuit, 7 is a phase shifter, 8 is a transmitting antenna formed of a copper pattern on the substrate, 9 is a case, 4 is a lid, and 33 is a phase display. (30 ° in this example).

  FIG. 6 shows a circuit diagram of the radio wave type lane marker 13. In FIG. 6A, 5 is a receiving antenna of ferrite and a coil, 6 is a frequency multiplier circuit using a diode bridge, 7 is a phase shifter composed of a capacitor and a resistor, and 8 is a transmitting antenna shown in the circuit diagram. FIG. 6B is a block diagram showing the function of the radio wave type lane marker 13. When the frequency converter 37 is configured by a diode bridge, the frequency of the signal received by the receiving antenna 5 is doubled and transmitted. Output from the antenna 8. The signal waveforms at points E, F, and G in FIG. 6A will be described later.

  FIG. 7 is a diagram showing the components of the radio wave type lane marker 13 shown in FIG. The horizontal axis of the waveform in FIG. 7B indicates time, and the vertical axis indicates amplitude. As shown in the figure, the frequency of the 220 kHz received radio wave (E) received by the receiving antenna 5 is doubled by a frequency multiplier circuit 6 composed of a diode bridge and converted to a signal (F) having a frequency of 440 kHz. The Next, a phase difference of a predetermined amount (15 ° in FIG. 7B) is given by the phase shifter 7 composed of a capacitor and a resistor, and is transmitted from the transmission antenna 8 as a reflected transmission radio wave (G). This phase difference can be changed to any value by changing the circuit constant.

  Next, the operation of the lane marker 13 will be described. The lane marker 13 transmits a radio wave having a phase difference given by the phase shifter 7 at a frequency of 440 kHz, which is different from the received radio wave of a frequency of 220 kHz. Because the frequency of the reception radio wave and the transmission radio wave are different, even if a radio wave having a frequency of 220 kHz is transmitted from the transmission source (for example, the in-vehicle device 14) to the lane marker 13, the lane marker 13 transmits a radio wave having a frequency of 440 kHz different from that frequency. Since it transmits, there is no interference and the vehicle-mounted apparatus 14 can calculate the relative position of the lane marker 13 correctly.

  FIG. 8 shows an example of the embedded position of the radio wave type lane marker 13 and the phase to be added. As shown in FIG. 8, the lane marker 13 is embedded on a straight line in a direction orthogonal to the lane direction. Since the radio lane marker 13 has an arrival distance of about 2 m, it can be reflected to all vehicles traveling (because the lane width is 4 m or less) when embedded in the vicinity of the white line and in the center of the lane.

  FIG. 8 shows an example in which a number of phases such as up and down lane centers and white line neighborhoods are given to a three-lane road. In this example, the phase difference of each lane marker 13 is 360 ° / 15 = 24 ° because it has three lanes in the upper and lower lanes.

  Moreover, it is necessary to install a roadside machine corresponding to these lane markers 13 and communicate the position information of the lane markers 13. One radio beacon 11 is installed at one point, and an optical beacon 12 is installed corresponding to each lane marker 13 or two lane markers 13 installed nearby. The position information of the lane marker 13 only needs to communicate the phase and position information corresponding to the lane marker 13 with respect to one point, and has the same communication content.

  Next, the operation of the position locating system having the above configuration will be described with reference to FIG. FIG. 9A is a diagram showing the mounting position of the antenna when the vehicle 10 is viewed from the side, and a 220 kHz medium-long wave is constantly transmitted from the transmission antenna mounted on the bumper 41 of the vehicle 10. When the vehicle 10 approaches a position of about 2 m from the lane marker 13, the reflected wave from the 440 kHz lane marker 13 reaches the three receiving antennas of the bumper 41 of the vehicle 10. This reflected wave becomes maximum when the lane marker 13 is closest.

  That is, as shown in FIG. 9B, the line connecting the lane markers 13 becomes maximum when the bumper 41 of the vehicle 10 exceeds. From the signal level ratio of the 440 kHz radio waves arriving at the three receiving antennas at this time, the distance from the nearest lane marker 13 (the left or right direction information and distance of the vehicle 10) can be calculated with high accuracy. . This distance can be obtained by triangulation with at least two antennas and an in-vehicle device, and one antenna can be used for calibration.

  Further, the phase information (72 ° in FIG. 9B) from the nearest lane marker 13 is also detected. In the vicinity of the lane marker 13, the radio beacon 11 or the optical beacon 12 is installed, and the phase and position information of the lane marker 13 are communicated. It is possible to accurately calculate the position of the vehicle 10 when the lane marker 13 is exceeded.

  For example, in FIG. 9B, the position information (latitude and longitude) of the lane marker 13 having a phase of 72 ° is (A1, B1), the position information of the lane marker 13 having a phase of 48 ° is (A2, B2), If the distance is D and the distance between the center of the lane and the receiving antenna (center) 44 is d, the position (latitude, longitude) of the vehicle 10 is ((A1 + A2) d / D, (B1 + B2) d of the center of gravity by triangulation. / D).

  Based on the position information of the vehicle 10 described above, the vehicle position locating unit 64 corrects the position information calculated by the inertial navigation positioning unit 62 (direction sensor + vehicle speed sensor). Since this correction is effective in areas where sufficient GPS satellites cannot be captured (for example, high-rise buildings, tunnels, underground malls, etc.), it is necessary to install infrastructure such as radio wave beacon 11, optical beacon 12, and lane marker 13 Only in these areas. The infrastructure installation interval may be set so that the position error due to inertial navigation reaches an error that causes a problem with high-accuracy positioning. For example, the infrastructure is embedded every 1 km as shown in FIG.

  Since the improvement of the position accuracy in the present embodiment is achieved not only in the horizontal direction of the vehicle 10 but also in the vertical direction, the embedment point of the lane marker 13 is set, for example, as a stop line on the roadway side of the crosswalk or a stop line It can be considered to be a few hundred meters ahead.

  The correction of position information by inertial navigation may be performed not only by correction by relative position determination of the lane marker 13 or the like but also by correction of absolute position determination by GPS or the like, and a position determination with a high reliability level can be selected. Moreover, even if it correct | amends with the combination, it is the same meaning as this Embodiment.

  In this embodiment, the radio lane marker 13 is used. However, the radio lane marker 13 can be similarly realized by changing the radio lane marker 13 to a magnetic lane marker. However, the magnetic lane marker corresponds to the phase of the radio lane marker. It is difficult to combine radio wave lane markers with only a negative binary polarity and a service area of 70m.

  In addition, since the configuration in the present embodiment is based on the car navigation device, it is advantageous in terms of cost to be integrated with the car navigation device.

  The position locating system and in-vehicle apparatus of the present invention are such that the position of the moving body is determined based on the position of the moving body with respect to the lane marker and the position of the moving body based on the position information of the lane marker, thereby preventing the GPS satellite from being sufficiently captured. In addition, for example, it is possible to provide highly accurate position positioning of several tens of centimeters to several meters, and it is possible to provide a service such as a driving support system, and the current position of a mobile object, particularly an automobile, can be highly accurate. It is useful as a position location system for detection and an in-vehicle device.

Schematic configuration diagram of a position location system in an embodiment of the present invention Explanatory drawing of the position location system in embodiment of this invention Configuration diagram of in-vehicle device and radio wave type lane marker in an embodiment of the present invention Schematic block diagram of an in-vehicle device in an embodiment of the present invention Structure diagram of radio wave type lane marker according to an embodiment of the present invention Circuit diagram of radio wave type lane marker according to an embodiment of the present invention Explanatory drawing of the phase of the received radio wave of the radio | wireless type lane marker concerning embodiment of this invention, and the reflected radio wave The figure which shows the example of the embedding of the radio wave type lane marker concerning embodiment of this invention, and the phase to provide. (A) is a figure which shows the mounting position to the vehicle of the antenna concerning embodiment of this invention, (b) is a figure which shows the position calculation example of the vehicle concerning embodiment of this invention, and a lane marker Schematic configuration diagram of a conventional location system

Explanation of symbols

DESCRIPTION OF SYMBOLS 4 Cover 5 Reception antenna part 6 Frequency low multiplier circuit 7 Phase shifter 8 Transmission antenna part 9 Case 10 Vehicle 11 Radio wave beacon 12 Optical beacon 13 Lane marker 14,124 In-vehicle apparatus 31 Detector 32 Reception part 33 Phase display 34 Transmission antenna 35 Transmission part 36 Position detector 37 Frequency converter 41 Bumper 43 Receiving antenna (right)
44 Receiving antenna (center)
45 Receiving antenna (left)
DESCRIPTION OF SYMBOLS 51 Transmission amplifier 52,53,54 Reception amplifier 55 Phase difference detector 56 Oscillation circuit 57,58,59 Detection circuit 60 Relative position calculation part 61 GPS positioning part 62 Inertial navigation positioning part 63 Lane marker position information acquisition part 64 Vehicle position location part 65,121 GPS satellite 101,102 White line 122 Reference station 123 GPS correction site 125 GPS positioning device 126 Inertial navigation positioning device

Claims (13)

A position locating system for locating a moving object,
A lane marker that reflects radio waves emitted from the mobile body;
A roadside device that transmits position information indicating a position where the lane marker is installed;
An in-vehicle device mounted on the movable body,
The in-vehicle device includes a position detection unit that detects a position of the moving body with respect to the lane marker, a position information acquisition unit that acquires position information of the lane marker transmitted from the roadside device, and a position of the moving body with respect to the lane marker. And a position locating means for locating the position of the moving body based on the position of the moving body calculated based on the position information of the lane marker.   The position locating system according to claim 1, wherein the lane marker reflects a radio wave having a frequency different from a frequency of the radio wave emitted from the moving body.   The position locating system according to claim 1, wherein at least two of the lane markers are installed at different points within a radio wave reachable range from the moving body.   4. The position locating system according to claim 3, wherein a plurality of the lane markers are installed in a direction substantially orthogonal to the lane in the center of the lane and in the vicinity of the lane separation line.   The position locating system according to claim 1, wherein the position detecting unit includes at least two receiving antennas at different positions within a radio wave arrival range from the lane marker.   The position determination system according to claim 3, wherein the roadside device is a radio beacon that transmits position information of each lane marker.   The position determination system according to claim 3, wherein the roadside device is an optical beacon that transmits position information of each lane marker.   The position locating system according to claim 3, wherein each lane marker reflects radio waves emitted from the moving body with different phase differences.   The position locating system according to claim 8, wherein the position detecting unit identifies a lane marker based on a phase difference of radio waves reflected from the lane marker.   The position locating system according to claim 9, wherein the position locating unit specifies a lane in which the moving body travels by identifying the lane marker.   The vehicle-mounted device includes means for calculating the position of the moving body by inertial navigation using an azimuth sensor and a vehicle speed sensor mounted on the vehicle-mounted device, and the position locating means calculates the position of the moving body calculated by inertial navigation. The position locating system according to any one of claims 1 to 10, further comprising a unit that corrects the position of the mobile body that has been positioned. The position of the moving body is determined based on signals from a lane marker mounted on the moving body that reflects radio waves emitted from the moving body and a roadside device that transmits position information indicating a position where the lane marker is installed. An in-vehicle device,
Position detecting means for detecting the position of the moving body with respect to the lane marker;
Position information acquisition means for acquiring position information of the lane marker transmitted from the roadside machine;
An on-vehicle apparatus comprising: a position locating unit that locates the position of the moving body based on the position of the moving body based on the position of the moving body with respect to the lane marker and the position information of the lane marker.   The correction means which correct | amends the position of the said mobile body calculated by the inertial navigation using the direction sensor and vehicle speed sensor mounted in the said vehicle-mounted apparatus with the position of the said mobile body located by the said position location means. In-vehicle device.

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