JPH01119712A - Present position display apparatus - Google Patents

Abstract

PURPOSE:To urge the calibration of position data by alarming the generation of an error, by judging and displaying the generation of the error of estimated position data on the basis of the continuous distance of the non-coincidence of an estimated position with the present position on a road. CONSTITUTION:The present point is inputted by an operating part 2 to be set initially and a vehicle is allowed to run while a distance signal and an azimuth signal are inputted at every predetermined time from a running distance detection part and a running direction detecting part 4 in the first estimated position calculation part 6 to calculate an estimated position on the basis of dead reckoning. On the basis of the difference between this data and the road data stored in a road map memory 5, a road position is detected by the second estimated position calculating part 6'. It is judged whether this difference is within a predetermined threshold value and the data of the memory 5 or the data of the estimated position is displayed on a display 1 as the present position. When said difference is the threshold value or more, the running distance in a free mode state is measured by a free mode measuring part 7 and, when said distance reaches a predetermined distance, the generation of an error is judged by an error generation discriminating part 8 and the display signal of a running locus is formed by the display signal forming part 9 and displayed on the display to be confirmed by a driver.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a device that displays the current position of a vehicle, and more specifically, the present invention relates to a device that displays the current position of a vehicle.
and the amount of direction change, and then select the estimated position determined by the accumulated data and the estimated position on the road network according to the difference between the estimated position directly determined by the accumulated data and the road network data stored in memory. The present invention relates to a novel vehicle-mounted position display device that displays a position.

<Conventional technology> Conventionally, methods for detecting and displaying the position of a vehicle traveling at any point on a road transportation network have been based on a distance sensor, a direction sensor, and the necessary output signals from both sensors. A proposed δill navigation method has been proposed, which is equipped with a processing device that performs processing, integrates distance changes and azimuth changes that occur as the vehicle travels, and displays the road network along with the vehicle's current position. Errors that the distance sensor and direction sensor inevitably have are accumulated as the vehicle continues to drive, and the vehicle's position is displayed based on the obtained estimated position data, so there is no discrepancy between the road network and the vehicle's displayed position. has grown larger,
There is a problem with not knowing where you are driving.

As a display method that takes this positional shift problem into account, the above recommendation J
The estimated position data obtained based on the Ill navigation is compared with the road position data stored in memory in advance, and the amount of deviation between the position data and the road position data is calculated as a cumulative error, and the estimated position data is added to the above estimated position data. The estimated position data is corrected for the cumulative error, and the estimated position data is matched with the road position data.
A map matching method has been proposed that displays the position of a vehicle on the road (U.S. Patent Section 3.789.19).
11 in the specification).

Specifically, estimated vehicle position data is calculated based on vehicle travel distance data obtained by a distance sensor and vehicle travel direction data obtained by a direction sensor, and the calculated estimated position data and preliminarily Compare the road position data stored in memory, and if the difference between both data is within a predetermined threshold, the position data is corrected to locate on the nearest road, and vice versa. If the value exceeds a predetermined threshold value, no correction is performed at all, so that the correction is performed with high accuracy as a whole, and the current position is accurately displayed.

<Problems to be Solved by the Invention> However, in the position display method using map matching, if the difference between the two data is greater than a threshold value (for example, when a truck approaches, or when driving under an elevated track or at a railroad crossing, an external magnetic field If an excessive error occurs in the direction sensor due to the influence of As a result, if the vehicle continues to drive, the errors will accumulate and become irrecoverable errors.

More specifically, in the above system, the estimated position and road position are calculated at intervals of several seconds, and due to errors in the estimated position data (for example, distance measurement errors, map memory errors, etc.), or The difference between the two sets of data frequently exceeds a predetermined threshold due to a visit to a point that is not stored in memory, etc., and a warning to that effect is issued each time the difference between the two data exceeds a predetermined threshold. This has the disadvantage of causing anxiety. Also, in most cases, errors of this degree can be recovered by continuing to drive.
No special warning means are provided.

However, since this method does not take into account the occurrence of excessive errors in estimated position data that occur particularly when affected by an external magnetic field, this error cannot be recognized, resulting in the above-mentioned inconvenience.

<Object of the invention> This invention was made in view of the above problems,
It is an object of the present invention to provide a current position display device that can warn that an error exceeding an allowable range has occurred in current position data and prompt the calibration of the position data.

Means for Solving Problems> In order to achieve the above object, the current position display device of the present invention measures the continuous distance in a state where the estimated position determined by the integrated data and the road network data do not match. a free mode measuring means; an error occurrence determining means for determining that an error has occurred in the estimated position determined by the integrated data on the condition that the continuous distance of the non-matching state exceeds a predetermined distance; and warning signal generating means for generating a signal warning of the occurrence of a positional error.

However, the continuous distance may be in units of road units.

Furthermore, the signal that warns of the occurrence of an error in the estimated position may be a signal that highlights the estimated position of the vehicle. However, it is preferable that the estimated position is represented by a travel trajectory.

Furthermore, the signal warning of the occurrence of an error in the estimated position may be a voice.

With the above current position display device, the distance traveled by the vehicle and the amount of change in direction are obtained and integrated at predetermined timings, and the estimated position determined directly from the integrated data is combined with the road network data stored in the memory. When driving while selecting and displaying the estimated position determined by the integrated data and the estimated position on the road network according to the difference between , when the vehicle position cannot be displayed on the road, the free mode measurement means measures the continuous distance in which the estimated position and the road network data do not match, and the error occurrence determination means determines whether the above coincidence occurs. It is determined that an error has occurred in the estimated position on the condition that the continuous distance in the state of not moving exceeds a predetermined distance,
Since the warning signal generating means generates a signal warning of the occurrence of an error in the estimated position according to the above determination result, it is possible to make the driver aware that there is an error in the estimated position data, and prompt the driver to calibrate the position data. be able to.

In other words, even during normal driving, the difference between the estimated position determined by the integrated data and the affected position on the road network may exceed a predetermined threshold due to errors that the direction sensor, distance sensor, map memory, etc. inevitably have. In most cases, the error can be recovered by driving a predetermined distance, so the error is stored in the memory after the predetermined distance has been traveled, without displaying a message that an error has occurred each time it occurs. By determining that an error has occurred in the estimated position data only when the position on the road cannot be detected, it becomes possible to accurately detect that an error has occurred.

Furthermore, if the predetermined distance is in units of road, even if the vehicle travels a considerable distance, the location data can be easily calibrated because the error occurrence point and the current location are on the same road.

Furthermore, the same effect as described above can be achieved even when the signal warning of the occurrence of an error in the estimated position is a signal highlighting the estimated position of the vehicle. When the estimated position is represented by a driving trajectory, the driving trajectory from the point where the error occurred can be compared with the road pattern, and the form of positional deviation can be seen, so the position data can be calibrated accurately. be able to.

<Example> Hereinafter, embodiments will be described in detail with reference to the accompanying drawings showing examples.

FIG. 1 is a block diagram showing an embodiment of the current position display device of the present invention, which includes a display (1), an operation section (2) for inputting an initial setting position (current location), etc., and a travel distance detection section. (3), a driving direction detecting section (4), a road map memory (5) which stores the road network of a predetermined range in advance, and a rain detecting section (3) outputted from (4) at predetermined time intervals. A first estimated position calculation unit (6) that calculates an estimated position by inputting a traveling distance detection signal and a driving direction detection signal, and a difference between the estimated position and the road network data in the road map memory (5) is determined by a predetermined value. a second estimated position calculation unit (6') that calculates the estimated position on the road (road position) when the second estimated position is equal to or less than the threshold;
a free mode measurement unit (7) that continues to measure the travel distance in a state where the estimated position and the road network data are equal to or higher than a predetermined threshold (hereinafter referred to as free mode); an error occurrence determination unit (8) that determines that an error has occurred in the estimated position on the condition that it exceeds the estimated position; and an error occurrence determination unit (8) that determines that an error has occurred in the estimated position on the condition that and a trajectory display signal generation section (9) that generates a driving trajectory by connecting the driving paths and a signal for highlighting the driving trajectory.

To explain in more detail, the display (1) displays the road network, estimated vehicle position or road position, travel trajectory, etc. stored in the road map memory (5). A device capable of two-dimensional display, such as a liquid crystal panel, can be used.

The operation unit (2) has a group of keys, such as a point specification key for specifying a point such as a destination or current location, and a correction key (not shown) for instructing correction of estimated position data.The above point specification key operation It is possible to input the current location, that is, initial setting data.

The mileage detection unit (3) has, for example, a photoelectric switch that detects the rotation of the wheel, and obtains the rotation speed of the wheel by counting the number of output pulse signals from the photoelectric switch.
Any configuration that calculates the traveling distance per unit time by multiplying by a predetermined constant indicating the outer circumference of the wheel using a multiplier may be sufficient, but it is also possible to calculate the traveling speed of the vehicle based on Doppler shift etc. and integrate it. A conventionally known configuration such as one that calculates the traveling distance can be used.

As the traveling direction detection section (4), for example, a geomagnetic sensor that outputs rotation angle data per unit time by detecting the horizontal component of the geomagnetism can be used, but a gyro or the like can also be used.

The road map memory (5) stores road network data (combined data of points and lines indicating the direction of roads, distances between branch points, etc.) over a predetermined range in advance, and is stored in a semiconductor memory, a cassette, etc. Tapes, CD-ROMs, etc. can be used.

The first estimated position calculating section (6) receives distance data output from the traveling distance detecting section (3) and rotation angle data Δθ output from the traveling direction detecting section (4) at each of the predetermined timings. Based on , the east-west component of the above distance △
X(-△JXcos△θ), and the north-south direction component △y(
−ΔJXsinΔθ)
1), and the estimated position data (Px'+
Δx, Py'+Δy).

The second estimated position calculation unit (6') calculates the estimated position data (P
x'+Δx, Py'+Δy) and position data (Px) on the road network stored in advance in the map memory (5).

Py) and determines whether the difference between both data is within a predetermined threshold or not, and if the difference between both data is within a predetermined threshold, A road position data output unit (G2°) that outputs the data (Px, Py) as the current position, and an estimated position data output unit (G2°) that outputs the estimated position data when the difference between both data exceeds a predetermined threshold. 63'). In order to deal with complex road networks, it is preferable not to set an error range for the predetermined threshold value, but if the error range is too small, the driving direction detection section (4) will inevitably have an error. Since positional deviations between the estimated position data and the road position data occur frequently, the range is set in consideration of errors in the driving direction detection section (4), map memory (5), etc.

The free mode measurement unit (7) receives the estimated position data signal as input, and while this estimated position data is output,
That is, the distance traveled in the free mode state is measured.

The error occurrence determining section (8) determines that an error exceeding an allowable range has occurred in the distance data ΔJ1 and the rotation angle data Δθ when the travel distance in the free mode state reaches a predetermined distance. On the contrary, estimated position data (Px'+△x, Py'+Δy) is generated before reaching the predetermined distance.
and the current position on the road (Px.

Py) substantially match, it is determined that the error has been corrected.

Regarding the distance for determining the free mode state, to be more specific, the distance to stop at nearby points on the road for meals, breaks, etc., and which road is currently being displayed. Considering the distance that can be determined from the net, it is set to approximately 1kn+.

The trajectory display signal generation unit (9) is connected to the matching determination unit (131
A position memory that sequentially stores the previous road position (Px', Py') and estimated position data obtained at predetermined time intervals after calculating the previous road position, in response to an error signal greater than a predetermined threshold from '). (91) and the error occurrence determination section (8)
An emphasis section (92 ). Note that it is also possible to provide a sound generating device that warns that an error is generated in accordance with the emphasis signal.

The operation of the current position display device is as follows.

The current location is input and initialized using the operation unit (2), the vehicle is driven, and the first estimated position calculation unit (6) detects the travel distance detection unit (3) and the travel direction detection unit (3) at predetermined intervals. 4) calculates the estimated position based on dead reckoning using the distance signal and direction signal as input, and the second estimated position calculating section (6') calculates the estimated position from the first estimated position calculating section (6). The road position is detected based on the difference between the position data and the road data stored in the road map memory (5). Then, display the estimated position or road position on the display (1)
is supplied to. Next, free mode total 71? J part (7
), measure the distance traveled in free mode,
The error occurrence determination unit (8) determines that an error exceeding the allowable range has occurred based on the continuous distance of the free mode state. Next, the trajectory display signal generation section (9) generates a signal for highlighting the traveling trajectory according to the error detection signal and supplies it to the display (1), thereby detecting the traveling distance detecting section (3) and the traveling direction. It is possible to make the driver aware that the data from the detection unit (4) has an error exceeding the permissible range.

To explain in more detail, the driver operates the point designation key to input the current location (PxO, PyO),
PXO, PyO) are temporarily stored in the position memory. After the vehicle starts, the running pressure 11iI detection unit (3) obtains a running distance signal, the running direction detection unit (4) obtains a direction signal, and the first
The estimated position calculation unit (6) calculates the current position (PxO, P
Based on the distance data Δ41 after a predetermined time has elapsed from yO) and the rotation angle data Δθ1, the east-west direction component ΔX1 and the north-south direction component Δy1 of the distance data are calculated, and the initial setting position (PxO) is calculated.

The coordinate position (estimated position) (PXO+Δ
x+, PyO+Δy+). Furthermore, the second estimated position calculation unit (6') calculates the coordinate position (PXO+△
xl, PyO+△y+) closest road map memory (5
) on the road, and if this difference is within a predetermined threshold, this position (
PXI, Py+) is displayed on the display (1) as the vehicle's current position. Conversely, if the difference exceeds a predetermined threshold, the estimated position data (PXO+△x1.PyO+△y+) is displayed on the display (
1). As described above, the road position is calculated at predetermined time intervals, and the road position displaced from the previous position is calculated. That is, while driving, the previous position (Px'
, Py'), the east-west direction component △X of the above distance is calculated based on the distance data △J and the rotation angle data △θ
(-△JXcos△θ), and the north-south direction component △y (-
△JXsinΔθ) is calculated, and the previous position (Px',
Estimated position data (Px'+ΔX) is obtained by adding each of the above components Δx1Δy to Py').

py'+△y), and the previous position data (Px',
Pyo) and displacement position data (PX'+△x, Py'+Δ
Calculate the current position (Px, Py) on the road stored in the road map memory (5) within the error range that may exist in relation to y), and combine the estimated position and the road position. The error is displayed on the display (1). The above-mentioned error range is set based on the error that the traveling distance detecting section (3) and the traveling direction detecting section (4) inevitably have in a normal state that is not affected by an external magnetic field or the like.

Next, the free mode measurement unit (7) uses the estimated position data (PX' + Δx + PY° + Δy) and the road position (P
X, Py) is greater than a predetermined threshold,
Measure the distance traveled from the previous position (PX', Py'). Further, the error occurrence determination unit (8) determines that an error has occurred in the estimated position data when the travel distance in the free mode state reaches a predetermined distance.

Next, the trajectory display signal generation section (9) generates position data from the previous road position stored in the position memory (91) to the current point in accordance with the output signal from the error occurrence determination section (7). The driving trajectory is generated by integrating the data. By generating a signal that highlights the trajectory and supplying it to the display (1), it is possible to warn that an error has occurred in the estimated position data and to prompt the user to calibrate the position data. can.

Figure 2 shows a specific display form, and shows the estimated position data (P
x'+△x, py+△y) and road position (Px, Py)
If the difference is within a predetermined threshold range (E), the vehicle position is displayed on the road at predetermined timings as indicated by points (A). However, if an excessive error occurs in the rotation angle data, the estimated position (B) obtained at the next timing will be outside the threshold range (E). This threshold range (
If the estimated position data (B) shown by the broken line after looking from E) does not recover to within the threshold range (E) even after traveling a predetermined distance, The driving trajectory is highlighted.

In summary, when driving while detecting the road position based on the output signals from the travel distance detection section (3) and the travel direction detection section (4), due to the influence of external magnetic fields, etc. If the estimated position and road network data do not match, an error exceeding the allowable range will occur in the estimated position data, that is, the traveling distance detection section (3) and the traveling direction detection section (4), depending on the continuous distance in the free mode state. By determining whether the vehicle is running and generating and displaying the travel trajectory after unmatching, it is possible to warn that the estimated position data has an error that exceeds the allowable range, and to prompt the calibration of the estimated position data. .

It should be noted that the present invention is not limited to the above-mentioned embodiments; for example, instead of displaying the traveling trajectory, the position on the road can be replaced with a dot display to display the traveling trajectory; , the distance for determining the free mode state is approximately 11
It is also possible to set it for each road unit (between intersections, between traffic lights, etc.) instead of for each un, and it is also possible to make various design changes without changing the gist of this invention. .

<Effects of the Invention> As described above, this invention solves the problem that when driving by map matching, an error occurs in the estimated position data based on the continuous distance of discrepancy between the estimated position and the current position on the road. It is unique in that it determines that there is an error in the estimated position data, and also displays a message indicating that an error has occurred in the estimated position data, warning the driver that an error has occurred and prompting the driver to calibrate the estimated position data. be effective.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a current position display device of the present invention, and FIG. 2 is a diagram showing an outline of a display form. (1)...Display, (6)...First estimated position calculation section, (6')...Second estimated position calculation section, (7
)...Free mode measurement section, (8)...Error occurrence determination section, (9)...Trajectory display signal generation section Patent applicant Sumitomo Electric Industries, Ltd. i'l- Agent Patent attorney Kamei Hirokatsu i knee! (2 others)

Claims (4)

[Claims] 1. The distance traveled by the vehicle at each predetermined timing, and the amount of direction change, and then integrate the integrated data. Estimated position and memory determined directly by data The difference between the road network data stored in Accordingly, the estimated position determined by the integrated data Select and display the location and estimated location on the road network. Vehicle-mounted position display device as shown , determined by the above cumulative data. Estimated location and road network data do not match Free mode to measure the continuous distance of the state Measuring means and continuation of the above inconsistent state provided that the distance exceeds a predetermined distance. to the estimated position determined by the integrated data. Error occurrence determination to determine that an error has occurred and the estimated position according to the above judgment result. An alarm system that generates a signal to warn of the occurrence of an error. and a warning signal generating means. Current position display device. 2. The given distance is in units of road. The present invention as stated in claim 1 above Position display device. 3. A signal warns of an error in the estimated position. Above is a signal that highlights the estimated position of the vehicle. Claim 1 or 2 Current position display device. 4. Although the estimated position is represented by a travel trajectory, As stated in claim 3 above, which is current position display device.