JPS6364726B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a positioning method using radio navigation devices such as Loran, Omega, Detsuka, etc., and in particular, the apparent positioning accuracy of the navigation device by reducing the influence of error factors specific to radio navigation. on how to improve.

Error factors specific to radio navigation include the divergence and intersection angle of position lines, and this influence increases as the divergence increases and the intersection angle decreases. For example, in Loran, which calculates position lines with a time difference of 0.1 μs, the error is relatively small at around 40 to 50 m near the intersection of baselines, but at the position where the divergence and intersection angle are the worst, the error is 200 to 50 m. 300
It extends to m. In other words, depending on the sea area, a change of 0.1 μs will cause a positional shift of 200 to 300 meters in the displayed latitude and longitude. Therefore, in order to eliminate this error and improve accuracy, conventionally a positioning method has been implemented in which positioning data is averaged as appropriate. In this method, positioning data is averaged by exponential smoothing or the like within an appropriate period, and the result is used as the current positioning position.

However, such a positioning method has the disadvantage that a time delay occurs due to averaging processing, and furthermore, if the accuracy is to be further improved, a further time delay occurs.

An object of the present invention is to provide a positioning method that does not cause time delays and does not cause large errors even in sea areas where position lines have a large divergence and a small intersection angle.

This invention was made based on the fact that an error of 200 to 300 m greatly exceeds the normal ship speed range when converted into speed.

In hybrid navigation that combines radio navigation and dead reckoning, this invention sets a movement limit range for a ship based on speed information from a dead reckoning device, and calculates the measured movement value based on the positioning result of the radio navigation device. Compare with the limit width, if the measured value is within the limit width, use the same value, if it exceeds the maximum value, change the maximum value,
The feature is that when the amount is less than the minimum value, the minimum value is regarded as the amount of movement.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a navigation device that implements the positioning method of the present invention, and FIG. 2 is a flowchart showing the operation of the navigation device.

The navigation device of this embodiment uses hybrid navigation that combines radio navigation and dead-reckoning navigation, uses Loran 1 as the radio navigation device, and includes a log and a gyroscope to set limits on the amount of movement of the ship. Dead reckoning navigation equipment 2 is used.

Loran 1 outputs position line 1 (hereinafter referred to as lop1), position line 2 (hereinafter referred to as lop2), and station code, and latitude/longitude converter 3 calculates latitude/longitude information from these information. The calculated latitude and longitude information is displayed on the display 4.

The dead reckoning device 2 outputs the ship speed divided into a speed V in the latitude direction and a speed Vλ in the longitude direction, and the position change calculation unit 5 calculates the position change for each lop measurement time of Loran with respect to the reference position from this speed information. The limit width D is
The limit width D ₁ in the latitude direction and the limit width D ₂ in the longitude direction are calculated and output to the latitude/longitude converter 3 .

Next, the operation of this navigation device will be explained with reference to FIG.

FIG. 2A shows the operating procedure of the dead reckoning navigation device consisting of the dead reckoning device 2 and the position change calculation unit 5. At step n ₁ (hereinafter step ni is simply referred to as ni), the dead reckoning device 2 calculates the latitudinal velocity V and the longitudinal velocity.
Vλ is measured. Usually this speed unit is KT (knots). In n ₂ , an error tolerance value is added or subtracted from these speeds V and Vλ to obtain speed limit values (minimum value and maximum value) that are considered to normally occur. In this example, the above error tolerance is 5KT,
This value may be varied depending on the sea area, etc. Next, at _n3 , the movement amount limit value for each measurement time is determined from the above-mentioned speed limit value and the measurement interval of Loran 1, and the difference between the minimum value and the maximum value, that is, the maximum movement limit width D is determined. dmin and dmax are the minimum (restriction) value and maximum (restriction) value for the amount of movement in the latitude direction, and dλmin and dλmax are the minimum (restriction) value and maximum (restriction) value for the amount of movement in the longitudinal direction.

On the other hand, the operation shown in FIG. 2B is executed by the Loran navigation device asynchronously with the above operation. This figure 2B
All of the steps shown in , except for n ₁₃ and n ₂₀ , are executed by the latitude/longitude converter 3, and are actually executed by the microcomputer built in the converter 3.

First, in _n10 , estimated positions q (latitude position) and λq (longitude position), which are the reference positions of the position to be measured from now on, are set. This estimated position is usually the previously determined position. In n ₁₁ , from the estimated position and the master and slave station positions obtained from the station code, a conversion coefficient α,
Find β. Then the estimated position lopTC ₁ at n ₁₂ ,
Find TC ₂ . Next, at n ₁₃ , the current position lopT ₁ , T ₂
is measured with Loran 1. And this measurement lopT ₁ ,
T ₂ and the estimated position lopTC ₁ , TC ₂ obtained by calculation
The differences dT ₁ and dT ₂ are obtained as lop changes (n ₁₄ ), and these lop changes are converted into latitude/longitude changes d and dλ using the conversion coefficients α and β.

This procedure of n ₁₀ to _{n 15} is exactly the same as the procedure of the conventional positioning method.

Steps n ₁₆ to n ₁₉ are steps for suppressing the amount of change obtained in the above procedure to the limit width D obtained in step n ₃ . At first
In n ₁₆ , the limit width D ₁ and d of the amount of movement in the latitude direction obtained in n ₃ , and the limit width of the amount of movement in the longitudinal direction
Compare D ₂ and dλ respectively. If both d and dλ are within the limit width D ₁ and D ₂ , then d and dλ are set to the values △ and △λ for positioning position calculation (n ₁₇ ), but if d or dλ is within the limit width D ₁ Or if it is over D ₂ , proceed with n ₁₈ . That is, d is dmin
If it is less than or equal to △=dmin, and d is dmax
If it is above, Δ=dmax. Also, dλ
If dλmin or less, △λ=dλmin, and dλ is
If it is greater than or equal to dλmax, Δλ=dλmax. In this way, in n ₁₈ , a limit is placed on the positioning result of Loran 1, and when the amount of movement based on the positioning result exceeds the maximum value of the amount of movement that is normally considered, that maximum value is considered as the amount of movement at that time, Further, when the amount of movement based on the positioning result does not reach the minimum value of the amount of movement that is normally considered, the minimum value is regarded as the amount of movement at that time.

Once the movement amounts △ and △λ are obtained in this way, these values are added to the original estimated positions q and λq to obtain the measured positions s and λs (n ₁₉ ), and the values are further displayed on the display 4. (n ₂₀ ), and updates the estimated position for the next positioning (n ₂₁ ). The above processing is executed every measurement time of Loran 1.

As described above, according to the present invention, even if the positioning position is in a sea area where the position lines have a large divergence and a small intersection angle, it is possible to reduce the variation in the change in the positioning position. positioning error can be reduced without

[Brief explanation of drawings]

FIG. 1 is a block diagram of a navigation device that implements the positioning method of the present invention, and FIG. 2 is a flowchart showing the operation of the navigation device.

Claims (1)

[Claims] 1. In hybrid navigation that combines radio navigation and dead reckoning, a ship's movement limit width is set based on the speed information of a dead reckoning navigation device, and the movement distance measurement value based on the positioning result of the radio navigation device is used as the limit width. When the measured value is within the limit range, the value is taken as is, when it exceeds the maximum value, the maximum value is taken, and when it is below the minimum value, the minimum value is taken as the movement amount. positioning method.