JPH0637286Y2 - Combined heading measuring device - Google Patents

Description

[Detailed Description of the Invention] The present invention uses a radio wave of NAVSTAR / GPS system to detect the heading of a ship or the heading of an aircraft, and a heading measuring device that combines a GPS compass and a magnet compass. Regarding

The GPS heading measurement device uses GPS radio waves to measure the heading.Therefore, when the heading measurement value is fixed, the heading measurement is fixed due to interference of radio interference or interruption of radio waves due to obstacles. However, as shown in FIG. 1 (b), there are inconveniences such as a slight fluctuation around the true azimuth (a), and sometimes a large fluctuation. However, as shown in FIG. 2 (d), the indicated value when the heading of the ship is rotated once has the property of showing an extremely accurate indicated value. However, the minute fluctuations described above can be reduced by averaging.
On the other hand, in the case of the magnet compass, when the heading is fixed, as shown in FIG. 1 (c), the true heading (a)
On the other hand, there is the inconvenience of having a large error of several degrees to several tens of degrees (this is called deviation) peculiar to each region on the earth,
The indicated value is extremely stable. However, as shown in Fig. 2 (e), the indicated value when the heading is rotated once is indicated by the indicated value (f) including an error peculiar to each region on the earth.
There is an inconvenience that the indicated value of the fluctuation of about 2 cycles is shown around this (this is called the error). In addition, when the heading changes due to a needle change or the like, the GPS heading measuring device has a slow follow-up due to averaging, but the magnet compass has a fast follow-up.

The present invention aims to obtain a highly reliable measurement value of the heading by combining the GPS heading measuring device and the magnet compass with the characteristics of the measurement errors which are just complementary. However, it will be described in detail below with reference to the drawings.

FIG. 3 shows an embodiment of the present invention, 1 is a magnet compass, 2 is a converter for converting the indicated value of the magnet compass 1 into an electric signal, and 3 is a GPS heading for determining the heading G
PS bow direction measuring device, 4 is a correction calculator. This correction calculator 4 receives the heading θ _M measured by the magnet compass 1 transmitted from the converter 2 and the heading θ _G transmitted from the GPS heading measuring device 3 to calculate the true heading. Correction calculation of.

Now, θ _M −θ _G is obtained from the values of θ _M and θ _G measured when the previous GPS heading measuring device 3 was operating stably.
Also, from the values of θ _M and θ _G measured this time, similarly, θ _M −θ _G
Ask for. If the difference between the previous θ _M −θ _G and the current θ _M −θ _G is more than the set threshold value, it is considered that there is an abnormality in the measurement of the GPS bow direction measuring device 3 at that time, and this time. By not adopting θ _G for measurement, remove abnormal measurement values due to GPS radio wave abnormality. Next, a set of θ _M and θ _G at each time point is obtained from a large number of measured values of θ _{G from} which abnormal data is removed in advance and a measured value of θ _M measured at the same time.

On the other hand, the error model ε for the true heading θ of θ _M
(Θ) is approximately ε (θ) = Σ ^N _{i = 0} AiSin (iθ +
φ), the coefficient Ai is obtained by means such as the least square method using the measured values of the plurality of sets of θ _M and θ _G , and the error model ε (θ) of the magnet compass is obtained. This calculation is repeatedly performed due to needle changes, yawing, etc., and always uses the latest error model ε.
(Θ), and the correction value ε obtained by this error model
Add (θ _G ) to θ _M measured this time to obtain the true heading.

As described above, according to the present invention, it is possible to always automatically and accurately indicate the heading direction without requiring any manpower, without being affected by the movement position of the ship and the fluctuation of the magnetic distribution inside the ship. Even when installed on a ship, there is no need to measure the deviation for correcting the deviation, and it is possible to give a more accurate heading indication than in the case of using a magnetic compass alone or a GPS heading measuring device alone. In addition, there is an advantage that it is possible to perform safe and highly accurate automatic navigation when using it on a ship or an aircraft.

[Brief description of drawings]

1 and 2 are explanatory views for explaining a conventional device,
FIG. 3 is a block diagram showing an embodiment of the present invention. 1 ... Magnet compass 2 ... Converter 3 ... GPS heading measuring device 4 ... Correction calculator

Claims (1)

[Scope of utility model registration request] 1. A GPS heading measuring device, a magnet compass, and a converter for converting a pointing direction of the magnet compass into an electric signal, and the heading θ _G measured by the GPS heading measuring device and the conversion. From the heading θ _M measured by the magnet compass transmitted from the vessel, the means for obtaining the measured value difference θ _M −θ _G at any time, and between the measured value difference when the GPS is operating stably and the measured value difference this time, and means to remove this unusual θ _G in the time of θ _G abnormally and considered when setting the threshold or more of difference that came out, abnormal θ _G has been removed θ _G
Theta _M using the means for obtaining the coefficients of the error model from a plurality of sets of theta _M, means for determining the error model epsilon (theta) to the true heading theta of theta _M using the coefficient, the said error model And a compensating calculator having a means for compensating the above to calculate a true compass direction.