JPS6218017B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a receiver for phase comparison navigation;
This invention relates to a Dekka coordinate converter for converting Dekka lanes into a latitude/longitude coordinate system for display.

The phase comparison navigation receiver is, for example, one known as a DECCA Navigator. In the Detsuka system, three slave stations are arranged in a star shape with a master station at the center, approximately 100 meters apart, and the master station and each slave station form pairs and emit radio waves of the same frequency. . This is received by a receiver installed on a moving object such as a ship. Then, the point where the phase difference between the radio waves from the master station and its paired slave station is constant is on the hyperbola, which is the locus of the point where the difference between the distance from the master station and the distance from the slave station is constant. By measuring the phase difference of the incoming radio waves at the receiver, it is possible to know on which hyperbola the mobile object is currently located. Furthermore, by performing this operation on pairs of the master station and other slave stations, the position of the moving body can be determined as the intersection of two hyperbolas. Such a hyperbola is usually called a lane in the Detsuka system. In the Detsuka system, three slave stations subordinate to one master station are named red (R), green (G), and purple (P), respectively.

Lanes in the Detsuka system form a hyperbola connecting points where the difference in distance from the main station and each slave station is constant, and generally do not coincide with the latitude and longitude lines on the map. Previously, the method used was to use a map that superimposed Detsuka Lane with latitude and longitude, and read Detsuka Lane as latitude and longitude, but this was inconvenient, so
Attempts have been made to automatically convert Dekka lanes into latitude and longitude for display using a Dekka coordinate converter using a microprocessor.

FIG. 1 is an explanatory diagram showing an example of a digital reception system. In the figure, reference numeral 1 indicates an antenna, and a Detsuka radio wave input from the antenna 1 is detected by a Detsuka receiver 2 for a phase difference to generate a Detsuka lane signal. The Detsuka lane signal is applied to the Detsuka coordinate converter 3, from Detsuka lane to latitude,
The signal is converted into a signal indicating longitude and displayed on, for example, an X-Y plotter (not shown).

Such a Detsu Lane signal is a signal θ, which is a signal representing the phase difference between radio waves between the main station and the slave station, which is obtained by dividing the decimal part of the lane into 100 equal parts, that is, the % lane signal, and is expressed as the following two types of signals. It is output by

The signals in formula (1) are output for each pattern of R, G, and P, so there are six types in total. The Detsuka coordinate converter can convert two patterns by selecting two types of signals, so a total of four types of signals.
It is configured to obtain the current depth lane by extracting the % lane signal of each type of pattern and integrating this signal from the starting point.
Regarding the coordinate conversion method to calculate latitude and longitude from such % lane signals, for example,
It is described in FUJITSU Vol. 32 No. 4 separate volume "DP-80 Type Dekka Coordinate Conversion Processor".

However, the average value of lanes measured in this way at a certain point may not match the lane value calculated from the latitude and longitude of that point. Among these errors, fixed errors that do not vary over time are called system errors, and are based on various causes that occur in connection with the path of radio waves from the transmitting point to the receiving point. ,
Most of this is thought to be caused by the inaccurate assumed value of the radio wave propagation velocity used to calculate the hyperbolic pattern.

Therefore, it is necessary to correct this system error, but correcting based on radio wave propagation speed not only complicates calculations, but also makes it difficult to grasp the geographical meaning from a navigation point of view. Therefore, it is conceivable to perform correction by adding or subtracting a fixed amount of correction measured in advance for each sea area to or from the coordinate transformation results. Such a method is also advantageous because the systematic error exhibits a nearly constant bias for each ocean area within a certain range. That is, the display value in this case is determined by the following equation.

Display value = coordinate transformation result + correction value (2) In order to perform the calculation of equation (2) on the coordinate transformation result, add (+) to the east and north directions and (-) to the west and south direction to the correction value. System errors can be easily corrected by giving a sign and setting a correction value from the keyboard by setting (+) to increase the coordinate transformation result and (-) to decrease it. For such correction data, for example, the "Detsuka Correction Table" created by the Japan Coast Guard Hydrographic Department
It is described in.

By using such a correction method, the correction value matches the geographical sense, and the correction becomes easy.
However, the latitude and longitude are both determined so that degrees increase in the opposite direction with the 0° line as the border, and the northern and southern latitudes, as well as the eastern and western longitudes. Therefore, if a certain correction value is determined in a certain sea area that straddles the 0° line, the correction value will be given a constant sign and value regardless of latitude and longitude, so if a ship, etc. crosses the 0° line. This causes a phenomenon in which the correction applied to the coordinate transformation results is in the opposite direction. For example, in a certain sea area that includes the 0° longitude line, the correction value is + towards the east.
0.20′, from the coordinate transformation result that the moving object exists at 0.30′ east longitude, 0.50′ east longitude (=0.30′+
0.20′), but if you move westward and cross the 0° longitude line, for example,
From the coordinate transformation result that it exists at 0.30′, the west longitude
The display will be 0.50'(=0.30'+0.20'), which will result in a large error from the true position of 0.10' west longitude (=0.30'-0.20'). Therefore, in such sea areas, the above-mentioned correction method cannot be used.

The present invention aims to eliminate such drawbacks of the prior art, and its purpose is to use a fixed correction value determined by the direction even in sea areas including the 0° line of latitude and longitude. The object of the present invention is to provide a coordinate converter that can eliminate system errors by correcting coordinate conversion results. In order to achieve this purpose, the Detsuka coordinate converter of the present invention converts Detsuka lane signals into latitude and
In a Detsuka coordinate converter that converts into a signal indicating longitude, means for setting a correction value for the latitude and longitude converted from the Detsuka lane signal, adding the correction value to the converted latitude and longitude, and adding the correction value to the latitude or longitude signal. The present invention is characterized by comprising means for determining the corrected latitude and longitude signals by changing the sign of the correction value for the latitude or longitude and performing addition when the correction value changes by more than 0°.

Examples will be described below.

FIG. 2 is a block diagram showing the structure of an embodiment of the digital coordinate converter of the present invention. In the same figure, 11
is an analog multiplexer, 12 is a sample hold circuit, and 13 is an analog digital (A/D)
Converter, 14 is an input control circuit, 15 is an interface circuit, 16 is a keyboard, 17 is a microprocessor, 18 is a display, 19 is an output circuit, 20
21 is a correction result determination circuit, and 21 is a data bus.

A lane signal from a deck receiver (not shown) is input to an analog multiplexer 11.
Under the control of the input control circuit 4, the analog multiplexer 11 reads the H and V signals of two designated patterns among R, G, and P in a time-sharing manner.
This is input to the sample hold circuit 12. The sample and hold circuit 12 samples the input signal and holds it for a certain period of time. The A/D converter 13 A/D converts the sampled and held signals to generate a digitized signal, which is input to the microprocessor 17 via the data bus 21.

The digitized lane signal input to the microprocessor 17 consists of the H and V signals shown by equation (1) for each pattern as described above, and from this, the microprocessor performs the following calculations. Then, the % lane signal θ is determined.

θ=tan ⁻¹ (H/V) (3) The microprocessor 17 further performs necessary coordinate transformation on the obtained % lane signal for each pattern to calculate latitude and longitude. At this time, correction data necessary for correcting system errors is set by the keyboard 16, and the data on the keyboard 16 is interfaced by the interface circuit 15 and sent to the microprocessor 17 via the data bus 21. is input. The microprocessor 17 adds correction values to the obtained latitude and longitude to generate latitude and longitude signals whose system errors have been corrected.

The latitude and longitude signals corrected for system errors generated by the microprocessor are sent to the data bus 21.
The information is then added to the display 18, and the display 18 thereby provides a visual display of latitude and longitude. The latitude and longitude signals are also applied to the output circuit 19 via the data bus 21. The output circuit 19 thereby generates and outputs a signal for operating an external X-Y plotter (not shown) or the like.

On the other hand, the latitude and longitude signals are input to the correction result determination circuit 20 via the display 18. The correction result determination circuit 20 determines when the latitude or longitude value has changed by more than 0° and sends a signal to the microprocessor 17. The microprocessor 17 changes the sign of the correction value input from the keyboard 16 and adds the correction value to generate a corrected latitude and longitude signal. Therefore, even after the latitude or longitude exceeds 0°, the correction value set before the 0° line is not changed and can be used as is to correct the system error. Figure 3 shows the sign change of the correction value according to the method of the present invention, where the correction value at position (1) was +0.20' at first, but when it crossed the 0° line, it changed to position (2). Because of the position,
It is shown that the correction value has become -0.20'.

As explained above, according to the Detsuka coordinate converter of the present invention, in the sea area including the 0° line of latitude and longitude, the latitude and longitude are By performing coordinate transformation to This is convenient and allows the operator's geographical sense to match the sign of the correction value, making it extremely effective in using the Detsuka system.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing a decca reception system, Fig. 2 is a block diagram showing the configuration of an embodiment of the decca coordinate converter of the present invention, and Fig. 3 explains the sign change of the correction value according to the method of the present invention. This is a diagram. 1...Antenna, 2...Detsuka receiver, 3...
Detsuka coordinate converter, 11... Analog multiplexer, 12... Sample hold circuit, 13...
Analog-digital (A/D) converter, 14...
Input control circuit, 15...interface circuit, 1
6... Keyboard, 17... Microprocessor, 18... Display, 19... Output circuit, 20...
...Correction result determination circuit, 21...Data bus.

Claims (1)

[Claims] 1. In a Detsuka coordinate converter that converts Detsuka lane signals into signals indicating latitude and longitude, means for setting correction values for latitude and longitude converted from Detsuka lane signals, and adding the correction values to the converted latitude and longitude. and means for determining the corrected latitude and longitude signals by changing the sign of the correction value for the latitude or longitude and adding the correction value when the latitude or longitude signal changes by more than 0°. Detsuka coordinate converter.