JPS5835413A - Hybrid navigation system - Google Patents

Abstract

PURPOSE:To make the system highly precise, by obtaining the weighted average of position data at a weighting ratio corresponding to the evaluated value of the position data from a dead reckoning navigation device and a radio navigation device, with a plurality of lines of positions and measured results obtained by an NNSS receiver as references. CONSTITUTION:The orbit data and the lines of positions from the NNSS receiver 1 are inputted to a position measuring circuit 2a and a line of position memory 2b in a position measuring device 2. Meanwhile, the position data from a loran device 3a and the dead reckoning navigation device 3b in a navigation aid system 3 are computed to obtain the weighted average by a weighting function (f). The results are inputted to a memory 2c in synchronization with the input timing of the lines of positions from the receiver 1. At the same time the position data is inputted into memories 5a and 5b. The compensation as a result of the position measurement in the position measuring circuit 2a is applied, and the results are sent to memories 6a and 6b. The stored data in the memories 6a and 6b and in the memory 2b are compared in comparator circuits 7a and 7b, and the results are sent to an evaluating circuit 8. The load corresponding to the evaluated value is sent to the circuit 3c, and the weighted average is computed so as to enhance the overall accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a hybrid navigation system that uses the NN58 receiver as the core, an updated aid navigation device, an electric navigation device, and a 1m11 navigation device. Positioning lines can only be obtained at discrete intervals, so when 40 positioning lines are obtained, positioning is usually performed using the least squares method. Since it is necessary to know the movement of the aircraft, and it is also necessary to transpose the position line due to the movement, the necessary information to meet this request is generally provided by assistive navigation devices such as dead reckoning navigation devices and radio navigation devices. . Furthermore, by advancing the idea of such assistance navigation, assistance navigation equipment,
It is also possible to use both a dead reckoning navigation device and a radio navigation device, and form assistance information by taking a weighted average of their position information. With this configuration, it is possible to weight the position information from the single-vehicle navigation device so as to obtain the highest accuracy depending on the environment at the time.

However, since the factor that determines this weight is the product term such as the divergence of the position line at that time and the size of the ocean current, the state of this product term can be directly measured and the position from the assist navigation device can be determined before positioning. It is extremely difficult to automatically determine the above weighting ratio so that the information always has high accuracy.

Therefore, an object of the present invention is to use an aid navigation device that uses both a dead reckoning device and a radio navigation device as described above.
The purpose of this invention is to provide a hybrid navigation system in which positional information is always weighted optimally and positional information from an auxiliary navigation device is automatically made highly accurate regardless of the environment. Focusing on the fact that the position line obtained by the NN5S receiver is relatively accurate, we calculated the position lines obtained from the NN5S receiver and the positioning results from the NN5S receiver, respectively, from the dead reckoning navigation device and the radio navigation device. The present invention is characterized in that it is provided with an evaluation means for evaluating the position information of the evaluation means, and a weighted averaging means for performing a weighted average of the respective position information at a weighting ratio according to the evaluation value of the evaluation means.

Embodiments of the present invention will be described below with reference to page W:1. Figure 1 is a block diagram of a hybrid navigation system that is an embodiment of the present invention. In this embodiment, a Loran device is used as the radio navigation device.

In the figure, the NN58 receiver 1 outputs orbit information and position @ (LOP) to the positioning device 2, and a position line is output approximately every 25 seconds. The positioning device 2 has a built-in positioning circuit 2, a position line memory 2b, and a position information memory 2C as main components, and each of the memories 2b*2c has 40 storage areas.
are the position line from the NN5S receiver 1 and the position information (latitude information: ψ, longitude information
) are stored in correspondence, and the information input timing is synchronized for each of 1 to 40 pieces. In addition, the 40 pieces of information stored in the memory 2c are used as information for transposing the position line information stored in the memory 2b by synchronizing input with each position information, that is, as ship movement information, and are used for transposition work. is carried out in the positioning circuit 2 ◎ This transposition technology itself is common in the NN5S navigation system (as it is used and well known, the explanation of C'''e will be omitted.) The assist navigation device 3 is , a Loran device 3a%, a dead reckoning navigation device 3b including a ship speedometer and a navigation compass, and a weighted averaging circuit 3 that weights and averages the position information from these two navigation devices.
C, with the NN5S positioning result of the previous battle as the reference position,
The weighted average of the above two pieces of position information using the function f is output in synchronization with the position line input from the positioning device's memo')2clcNNSS receiver 1. In addition, the function f that determines the weighting ratio of the above two positional information should preferably give a larger weight to the Loran device 3 than to the past information seismic dead reckoning navigation device 3b, and the closer it gets to the present, the more weight to be given to the Loran device 3. It is preferable to use a so-called exponential smoothing function that increases the weight of the dead reckoning device, and it is desirable to change the degree of weight ratio change by changing the constant k. The reason for this is that dead reckoning calculates position information from moving speed and azimuth information, so the accuracy is not so bad when a relatively short time has elapsed from the reference time, but when the amount of movement is accumulated (over a long period of time) While radio navigation has the characteristic of increasing errors, it is independent every time (
Since the position is determined, the results vary widely, but
This is because there is a characteristic that the more the amount of movement is integrated, the closer it gets to the true value. Bird, when performing exponential smoothing like this, 1
．． The position line information, which is the output information from the stomach-toning device 3-Otori, is
In order to change the value to the cumulative amount of movement, it is necessary to convert it to speed information of the same dimension as the output of the dead reckoning navigation device 3b. This dimensional conversion can be easily realized by configuring a differentiation circuit including a slow circuit and calculating the difference between the current position line and the previous position line.

The above exponential smoothing process was proposed by the present applicant in a patent application filed on the same day (name of the invention "hybrid navigation"), and if you read the specification that describes the skeleton invention in detail, □ Next, we will explain the evaluation means for evaluating the position information of both navigation devices, which is a component of this invention.
The position information from the dead reckoning navigation device 3b is stored in the memory 5b together with the weighted averaging circuit 3C.

5a, and 40 pieces of position information are also stored in this memory. Note that while the position information in the memory 2C is a weighted average result value, this position information is each position information obtained independently from the pot navigation device 3be3m. Furthermore, the input timing of the 40 pieces of information is the same as that of the memory 2c (synchronized with the position line input timing from the NNSS receiving shore 1).

Now, when 40 position lines are input to memory 2b, and 40 position information are input to memory 2C and memory 5 (51, 5b), positioning is executed at the same time as the dislocation in positioning route 1 and positioning 2. Ru. Depending on the positioning result, the memory 5as5
The information stored in the memo 95a and 6b is subjected to supplementary B propagation correction, etc.), is dimensional-converted into rectified position line information, and is transferred to the memos 95a and 6b, respectively. Therefore, at this stage, the positional information obtained from the 1st, 2nd, 31% dead reckoning position 3b is dimensionally converted into position line information and stored in the memory. In this case, the dimensional conversion is between the Mae1 position obtained from the orbit information and the NN5S
This is done by calculating the distance between each position in the memory 5**5b which has been corrected based on the measured position.

Next, comparison circuits 72 and 7b compare the cape memory information in memories 61 and 6b with the information stored in memory 2b for each of the 40 pieces of information. That is, NN5S reception lI
High precision position line obtained from l.

A comparison is made between the position line based on the output of the Loran device 3b obtained in synchronization with the position line based on the output of the dead reckoning navigation device 3b. Then, the comparison results are sent to the evaluation circuit 8. This evaluation circuit 8 basically uses the position line obtained from the NN5S receiver 1 as a reference k and the output of the Loran device 31 (evaluation of the accuracy of the position line and evaluation of the accuracy of the position line based on the output of the dead reckoning device 3b). Generally, this accuracy evaluation is
The evaluation is performed by looking at the variance of the comparison results, but it is also possible to perform the evaluation using other statistical methods. The corresponding threshold value is output to the weighted averaging circuit 3C. In the above table, when the comparison result variance value of the comparison circuit 71 is large, the value is increased, and when the comparison result variance value of the comparison circuit 7b is large, the i value is decreased, and j! can be added by taking into consideration the accuracy of the NN5S receiver l. That is, when the accuracy of the Loran device 31 is evaluated to be poor, the friend value becomes large and a greater weight is given to the information from the dead reckoning device 3b, while the accuracy of the dead reckoning device 3b is evaluated to be poor. In this case, the permanent value becomes small and the weight of the information from the dead reckoning device 3b becomes small, and conversely, the weight of the information from the Loran device 3b increases. Therefore, the weighting ratio is automatically determined in accordance with the accuracy of the one-vehicle navigation device so as to improve the accuracy of the entire assist navigation device 3.

Furthermore, after the weighting ratio is determined in this way.

Until the position line information is obtained again from the NN5S receiver, the weighted average value based on the ratio, that is, the aid navigation device 3
(The I! indicator is not shown), and the position will eventually be displayed continuously.As detailed above, according to this IjlI#c, the dead navigation device and the radio Position information from navigation devices is dynamically weighted averaged to always form the most accurate aid information, making the system more accurate and automated, significantly improving the performance of hybrid navigation systems. be.

[Brief explanation of the drawing]

The figure is a block diagram of a hybrid navigation system that is an embodiment of the present invention. 1...NN5S receiver, 2...Positioning device, 3.
...Aid navigation device s 3c...Weighted averaging circuit, 7
...Comparison circuit, 8...Evaluation circuit. Applicant Furuno Electric Co., Ltd. Representative Patent Attorney Hisao Komori

Claims (1)

[Claims] A dead reckoning navigation device and radio navigation that provide information for transposing a plurality of position lines determined by a NN8S receiver. In a hybrid navigation system having an auxiliary navigation device including a navigation device, each position information from the dead reckoning navigation device and the radio navigation device is calculated based on the plurality of positions obtained next to the NN5S reception and the NN5S positioning results. 1. A hybrid navigation system comprising: an evaluation means for evaluating; and a weighted averaging means for performing a weighted average of each piece of position information at a weighting ratio according to the evaluation value of the evaluation means.