JPS62255886A - Moving position measuring instrument - Google Patents

Abstract

PURPOSE:To measure a position with high accuracy in spite of the of reception of a reflection wave of a navigation radio wave, by detecting the reception of the reflected wave of the navigation radio wave by monitoring a difference between an absolute position and a relative position in case when a receiving state of the navigation radio wave is good, and regarding the relative position in that case as the present position of a moving body. CONSTITUTION:A loran signal is received by a receiving circuit 12 and absolute position coordinates (XL, YL) of a moving body such as a vehicle, etc. are calculated by a receiving position arithmetic circuit 14. On the other hand, by an integrating operation from an azimuth by an earth magnetism sensor 16, a distance by a distance sensor 18, etc., an estimated position arithmetic circuit 20 calculates relative position coordinates (X0, Y0), and one of the coordinates (XL, YL), (X0, Y0) is selected by an arithmetic position selecting circuit 24. S/N, etc. at the time of reception of this circuit 12 are monitored by a receiving state monitoring circuit 22, and when the S/N is low, and also, a difference between the coordinates (XL, YL), (X0, Y0) is larger then a prescribed value by a reflected wave receiving and detecting circuit 26, it is decided that a loran reflected wave of a crest, etc. is detected, and the circuit 24, selects the coordinates (X0, Y0). Accordingly, a position is measured with high accuracy irrespective of reception of a reflected wave of a navigation radio wave.

Description

Detailed Description of the Invention (Field of the Invention) The present invention calculates the absolute position of a moving object using navigation radio waves, and calculates the relative position of the moving object by integrating the moving direction and distance of the moving object. The present invention relates to a mobile body measuring device that selects one calculated position as the current position of the mobile body depending on the reception state.

(Background of the Invention) This type of device is known from Japanese Patent Application Laid-Open No. 60-135817, and in that conventional device, an absolute position and a relative position are each selected as the current position of a moving object depending on the quality of navigation radio waves. ing.

However, in the past, when navigation radio waves reflected from large buildings, mountains, etc. are received when a moving vehicle is moving near large buildings, mountains, etc., when the reception condition is good at that time, Since the absolute position of the vehicle is determined from the reflected waves with a phase lag and the determined absolute position is selected as the current position of the vehicle, there has been a problem in that the accuracy of position measurement is significantly reduced.

(Object of the invention) The present invention has been made in view of the above-mentioned conventional problems,
The purpose is to provide a mobile position measuring device that is capable of highly accurate position measurement despite receiving reflected waves of navigation radio waves.

(Structure of the Invention) In order to achieve the above object, the present invention detects the reception of reflected waves of navigation radio waves by monitoring the difference between the absolute position and the relative position when the reception state of the navigation radio waves is good; It is characterized in that when the detection is performed, the relative position is selected as the current position of the moving object.

(Embodiments of the Invention) Hereinafter, preferred embodiments of the apparatus according to the present invention will be described based on the drawings.

FIG. 1 shows a device for measuring the current running position of a vehicle, and its antenna 10 receives Loran C radio waves.

Based on the reception data obtained by the reception circuit 12, the reception position calculation circuit 14 obtains position data (XL, VL) indicating the absolute current traveling position of the vehicle. The current traveling position of the vehicle is shown in latitude and longitude.

Furthermore, the traveling direction of the vehicle is detected by the geomagnetic sensor 16, and the traveling distance is detected by the distance sensor 18, and the estimated position calculation circuit 20 calculates the detected direction and distance by integrating them.
In this example, position data (xo, yo) indicating the relative position of the vehicle with respect to the reference position is obtained.

Note that the above reference position is given by position data (XL, yL), and the position data (XL, yL) is set immediately before radio wave reception becomes impossible.

Roughly speaking, the receiving state monitoring circuit 22 monitors the radio wave receiving state, and in this embodiment, the receiving state monitoring circuit 22 detects the SN ratio of the received signal obtained by the receiving circuit 12.

The SN ratio of the received signal is as per patent application No. 58-105540.
As shown in , it is determined probabilistically from the summation value of the binarized received signal.

Then, the SN ratio detection signal of this reception letter 5t34 viewing circuit 22, the position data (XL, y
L) and the position data of the estimated position calculation circuit 20 (XD, V
D) is provided to the calculation position selection circuit 24.

In this calculation position selection circuit 24, when it is confirmed from the SN ratio of the received signal that the radio wave reception condition is good, the position data (XL, yL> is the position data (x, , ¥1 ), and the received signal S
If it is confirmed that radio wave reception is no longer possible due to a drop in the N ratio, the relative position is recorded using the ISI data (xo, y
o) is position data (Xi,
It is selected as V Kasumi.

In this manner, the calculation position selection circuit 24 selects the absolute position and relative position of the vehicle as its current traveling position, depending on the quality of the radio wave reception state.

Here, the position data (X
L, yL), position data of the calculation position selection circuit 24 (Xo
, Vo) and the SN ratio detection signal of the reception status monitoring circuit 22 are given to the reflected wave reception detection circuit 26, and the reflected wave reception detection circuit 26 confirms that the radio wave reception status is good from the SN ratio of the received signal. and absolute position data (X
Reflected wave reception is detected when a large difference is recognized between the relative position data (xo, yo) and the relative position data (xo, yo).

Then, the detection signal is given to the calculation position selection circuit 24, and the calculation position selection circuit 24 uses the detection signal to convert relative position data (xo, yo> to position data (XH, yi) indicating the current traveling position of the vehicle. Selected.

The operation of this embodiment is explained in a flowchart in FIG. Movement amount data indicating the amount is obtained by the estimated position calculation circuit 20 (step 100)
.

Then, the receiving state monitoring circuit 22 receives the SN ratio and the set SN ratio C for each detected Loran station.

(for example, −26 dB>) is compared in the calculation position selection circuit 24 (step 102>), and if it is confirmed that the SN ratio of the received signal is equal to or higher than the setting S N Lt Co for all 092 stations (if the result is positive in step 102) judgment),
The reception position calculation circuit 1 uses the reception data of the reception circuit 12.
Position data (XL, yL) indicating the absolute position of the vehicle in 4
is obtained, and this position data (X L s y
L) is applied to the calculation position selection circuit 24 (step 104).

In the calculation position selection circuit 24, when the received signal SN ratio for each Loran station is equal to or higher than the set SN ratio Co, the reception position calculation circuit 14 uses data indicating the absolute position of the vehicle (
Since it is possible to calculate XL, yL> and to calculate it accurately, this position data (XLN yL> is selected as data □J % yH indicating the current traveling position of the vehicle) (step 106). .

Next, position data (X
o, yo) is changed to its position data (xL, yL) (step 108).

During the above operation, 19
If the received signal SN ratio falls below the set SN ratio Go and position measurement using Loran C radio waves becomes impossible (negative determination at step 102), position data indicating the relative position at that time is An integration process is performed in which the movement amount data is sequentially incremented for (Xo, yo), and the position data (xo, yo) obtained by the integration process becomes position data (xH) indicating the current traveling position of the vehicle. , yH) (step 110).

If the S/N ratio of Loran C radio waves decreases and position measurement using them becomes impossible, the relative position based on the absolute position obtained using Loran C radio waves immediately before and its relative position is selected as the current driving position of the vehicle.

Here, the received signal SN ratio of each Loran station is the set SN ratio Co
If the reception status is good (step 1)
02 (affirmative judgment), the previously determined position data (XL,')/L) and the current position data (XL, VL
) is used to find the distance 1iIP that the vehicle has traveled during that time (step 112), and in the same way, the distance that the vehicle has traveled during that time is found using the position data (xo, yo) (step 114). .

Next, the absolute value Q of the difference between these travel distances P and D is determined (step 116), and the distance difference Q is compared with the set distance QO (step 118).

At that time, if the vehicle is driving near a mountain as shown in Figure 3 and the reflected wave of the Loran radio wave is received by the antenna 10, the reflected wave will be different from the Loran radio wave as shown in Figure 4 ( A
As a result, the tracking point is also delayed by the value Δt as shown in Fig. 4 (B), for example, a delay of 1 μsec is 300 m.
This corresponds to the error of

The reflected wave reception detection circuit 26 detects the reception of reflected waves when the distance difference Q exceeds the set distance QO, and when this is detected, the reflected wave reception detection flag F is set and the calculation position selection circuit 26 detects this fact. 24 (step 120
>, the calculated position selection circuit 24 selects the relative position data (XD, VD) of the estimated position calculation circuit 20 as position data (x., yH) indicating the current traveling position of the vehicle (step 110).

Thereafter, while the reception of the reflected wave is confirmed because the flag F is set (affirmative determination in step 122), the position data (X, y), (XD%
'10) is used to find the positioning error K between the absolute position and the relative position (step 124), and the error K is the setting error K.
o (step 126).

If the error K exceeds the setting error Ko (negative determination in step 126), a foul wave of the Loran C radio wave has been received, and therefore the data indicating the relative position (Xo, y
o) is data (Xi,
Vi) is selected by the calculation position selection circuit 24, but
If the error K is less than the fixed error KO (affirmative determination in step 126), the reflected wave reception detection circuit 26 determines that the influence of the foul wave has faded, and the flag is reset by 1. (Step 128), and the calculation position selection circuit 24 receives the position data (XL
, :! l/L) is selected as position data □J, yH) indicating the current traveling position of the vehicle (step 106).

Note that in the reflected wave reception detection circuit 26, if the distance difference Q is less than or equal to the setting Qo and no reflected wave reception is detected (negative determination in step 118), the flag F is reset (step 128). , calculation position selection circuit 24
Then, the position data (XL, yL) becomes the position data (Xj,
Vi) (step 106).

In addition, the calculation position selection circuit 24 determines whether or not the reception condition has been continuously good (step 130).
Otherwise, the position data (XL, yL) indicating the absolute position is selected as the position data (X·, yi) indicating the current traveling position of the vehicle regardless of whether or not reflected waves are received (step 106).

As can be understood from the above explanation, in this embodiment, whenever the vehicle travels a predetermined distance, the reflection occurs when the difference between the absolute position and the relative position increases continuously in a specific section (several hundred meters). A determination has been made that a wave is currently being received, in which case position data (Xo, yo
) is selected as the position data (xH, yH) indicating the current traveling position instead of the data (XL, VL>) indicating the absolute position.

Therefore, according to this embodiment, it is possible to accurately measure the current traveling position of the vehicle despite receiving reflected waves.

In this embodiment, the distance difference Q is calculated for each predetermined distance, and the reflected wave reception is detected when the distance difference Q becomes equal to or greater than the set distance Qo over a predetermined section. Calculate the distance difference Q for each period of time (10 to 20
It is also possible to detect the reception of reflected waves when the distance difference Q becomes equal to or greater than the set distance Qo.

(Effects of the Invention) As explained above, according to the present invention, the relative position obtained by the fault processing of the moving direction and distance of the moving object is the current position of the moving object when the reflected wave reception is detected. Therefore, it is possible to accurately measure the current position of the moving object despite receiving reflected waves.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a preferred embodiment of the device according to the present invention, FIG. 2 is a flowchart explaining the operation of the embodiment shown in FIG. 1, FIG. 3 is a diagram explaining the reflected wave receiving operation, and FIG. FIG. 3 is a signal diagram showing a phase delay effect of reflected waves. 10... Antenna 12... Receiving circuit 14... Reception calculation circuit 16... Geomagnetic sensor 18... Distance sensor 20... Estimated position calculation circuit 22... Reception state monitoring circuit 24... Calculation position selection circuit 26...Reflected wave reception detection circuit Figure 3 Mountain V > 1 time - 7''

Claims (1)

[Claims] (1) Absolute position calculation means for calculating the absolute position of a moving object using navigation radio waves; Relative position calculation means for calculating the relative position of the moving object with respect to a reference position by integrating the moving direction and distance of the moving object; reception condition monitoring means for monitoring the reception condition; calculation position selection means for selecting the absolute position and the relative position as the current position of the moving body depending on whether the reception condition is good; reflected wave reception detection means for detecting the reception of reflected waves of navigation radio waves by monitoring the difference from the position; and reflected waves for selecting the relative position as the current position of the moving body when the reception of reflected waves of navigation radio waves is detected. A mobile position measuring device comprising: calculation position selection means at the time of reception;