JP3807845B2 - GPS navigation system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a GPS navigation device, and more particularly, to a GPS navigation device that can prevent measurement errors due to ship shaking.
[0002]
[Prior art]
In general, for example, a GPS navigation apparatus shown in FIG. 3 is known as a marine GPS navigation apparatus. The illustrated GPS navigation apparatus is mounted on a ship, and includes a GPS antenna unit 21, a GPS reception positioning unit 22, and a positioning result display unit 23. The GPS navigation device receives a radio wave from a GPS satellite by the GPS antenna unit 21 and performs positioning. As is well known, the GPS reception positioning unit 22 normally receives radio waves from four GPS satellites and obtains the position of the receiving device (that is, the position of the ship). At this time, the velocity component in the three-axis direction of the ship can also be obtained from the measurement of the pseudo distance change rate (Doppler frequency) between the four GPS satellites and the ship. That is, the moving speed (ship speed) of the ship can be obtained. Then, the positioning data and the moving speed are displayed on the measurement result display unit 23.
[0003]
[Problems to be solved by the invention]
In general, a GPS navigation apparatus performs positioning at a GPS antenna unit, that is, a position (point) where a radio wave from a GPS satellite is captured. When measuring ship speed, an instantaneous moving speed of the position of the GPS antenna unit is measured. It means that you are measuring.
[0004]
By the way, considering that the GPS antenna unit is mounted at a high position such as a mast, when the ship is shaken by wind waves such as stormy weather, the GPS antenna part is not changed even though the moving speed of the ship hardly changes. The position (point) of the section varies greatly according to the sway of the ship.
[0005]
Now, assuming that the moving speed of the ship hull itself is VR, the ship speed VR generally does not fluctuate due to the rolling / pitching of the hull, but the position of the GPS antenna is periodically changed in the traveling direction of the ship by pitching, for example. Fluctuates. Here, when this periodic speed fluctuation is VP, the ship speed Vm measured by the GPS navigation device is the result shown in FIG.
[0006]
On the other hand, when the measured ship speed Vm is averaged to avoid periodic fluctuations in the measured ship speed Vm, a response delay occurs in the averaged ship speed with respect to the actual ship speed. In other words, in general, data processing such as filtering is used when performing the averaging process. When such data processing is performed, the actual ship speed is changed, but the measurement ship is changed. The speed does not change (does not follow), resulting in a delayed response.
[0007]
As described above, the conventional GPS navigation apparatus has a problem that when the ship is shaken, the measurement ship speed fluctuates and the moving speed of the ship cannot be accurately grasped.
[0008]
An object of the present invention is to provide a GPS navigation apparatus capable of accurately measuring a ship speed without being subject to instantaneous fluctuations due to the shaking of the ship, and preventing a delay in response to the actual ship speed.
[0009]
[Means for Solving the Problems]
According to the present invention, an antenna unit that is mounted on a mobile body and receives radio waves from a GPS satellite, and the received radio waves received by the antenna unit are processed to calculate the position and moving speed of the mobile body as a positioning result. In a GPS navigation device having a GPS reception positioning unit that performs positioning and a positioning result display unit that displays the positioning result, an inclination angle that detects a tilt angle of the moving body with respect to a predetermined reference and obtains a detected tilt angle A detection unit, a fluctuation speed calculation unit that obtains a fluctuation speed of the position of the antenna unit as an antenna position fluctuation speed according to the detected tilt angle, and a correction that corrects the moving speed with the antenna position fluctuation speed to obtain a correction speed. A GPS navigation device having a speed calculation unit and providing the correction speed to the positioning result display unit instead of the moving speed is obtained.
[0010]
The moving body is, for example, a ship, the inclination angle detection unit measures an inclination angle with respect to the traveling direction of the ship, and the fluctuation speed calculation unit calculates a fluctuation speed with respect to the traveling direction.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below with reference to the drawings.
[0012]
With reference to FIG. 1, the illustrated GPS navigation apparatus is mounted on a ship, for example. The GPS navigation apparatus includes a GPS antenna unit 11, a GPS reception positioning unit 12, a positioning result display unit 13, an inclination angle detection unit 14, an antenna position fluctuation speed calculation unit 15, and a correction speed calculation unit 16.
[0013]
As described with reference to FIG. 3, this GPS navigation device receives radio waves from GPS satellites by the GPS antenna unit 11, performs positioning by the GPS reception positioning unit 12, and calculates the moving speed (measurement speed) of the ship. Then, the positioning data is given to the measurement result display unit 13. At this time, the measurement speed is given from the GPS reception positioning unit 12 to the correction speed calculation unit 16.
[0014]
Here, referring also to FIG. 2, the inclination angle of the hull is detected by the inclination angle detection unit 14 according to the motion of the ship, and is provided to the antenna position fluctuation speed calculation unit 15 as the detected inclination angle ΘP. That is, the tilt angle detection unit 14 detects the tilt angle of the hull with respect to a predetermined reference to obtain a detected tilt angle.
[0015]
The antenna position fluctuation speed calculation unit 15 calculates the fluctuation amount of the antenna position from the detected inclination angle ΘP and the height HA of the antenna part. Then, the antenna position fluctuation speed VP during a specified time (predetermined time) T is determined according to the fluctuation amount of the antenna position. Note that VP is approximately expressed by 2HA · sin (ΘP / 2) / T. The antenna position fluctuation speed calculation unit 15 gives the antenna position fluctuation speed VP to the correction speed calculation unit 16 (when this antenna position fluctuation speed is the same direction as the traveling direction of the ship, it becomes a positive value, and the traveling direction of the ship When the direction is the opposite direction, it becomes a negative value).
[0016]
As described above, the correction speed calculation unit 16 is supplied with the measurement speed from the GPS reception positioning unit 12, and the correction speed calculation unit 16 corrects the measurement speed Vm according to the antenna position fluctuation speed VP. In other words, the correction speed calculation unit 16 subtracts the antenna position fluctuation speed VP from the measurement speed Vm to obtain a correction speed (that is, a speed obtained by removing the speed fluctuation portion of the antenna part), and gives it to the positioning result display unit 13. Then, the positioning result display unit 13 displays the correction speed as the ship speed VR.
[0017]
In the above-described example, the example in which the antenna portion is inclined in the navigation direction of the ship has been described. However, the position variation of the antenna portion that is a problem when actually measuring the navigation speed of the vessel is relative to the navigation direction of the vessel. Although fluctuations in other directions are not a problem, the measurement speed can be corrected in the same manner when the antenna portion is inclined in a direction different from the navigation direction of the ship.
[0018]
As described above, in the present invention, since the ship measurement speed is corrected by the fluctuation speed of the antenna section, an accurate ship movement speed can be obtained without being affected by the instantaneous fluctuation of the antenna section.
[0019]
Furthermore, in the present invention, since the ship measurement speed is corrected without averaging the ship measurement speed by data processing such as filtering, a measurement speed without a response delay with respect to the actual ship speed can be obtained.
[0020]
【The invention's effect】
As described above, in the present invention, the fluctuation speed of the antenna unit is measured, and the ship measurement speed is corrected according to the antenna part fluctuation speed. However, there is an effect that the ship speed can be measured accurately and without a response delay.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an example of a GPS navigation apparatus according to the present invention.
FIG. 2 is a diagram for explaining a method for calculating an antenna unit fluctuation speed in the GPS navigation device shown in FIG. 1;
FIG. 3 is a diagram showing a conventional GPS navigation device.
4 is a diagram showing a comparison between a measured speed and an actual speed in the GPS navigation device shown in FIG. 3. FIG.
[Explanation of symbols]
11, 21 GPS antenna unit 12, 22 GPS reception positioning unit 13, 23 Positioning result display unit 14 Inclination angle detection unit 15 Antenna position fluctuation speed calculation unit 16 Correction speed calculation unit

Claims (2)

An antenna unit mounted on the mobile body for receiving radio waves from GPS satellites, and a GPS reception positioning unit for processing the received radio waves received by the antenna unit and calculating the position and moving speed of the mobile body as a positioning result; A GPS navigation device having a positioning result display unit for displaying the positioning result, and further detecting an inclination angle of the moving body with respect to a predetermined reference to obtain a detected inclination angle, and the detection There is a fluctuation speed calculation part that obtains the fluctuation speed of the position of the antenna unit as an antenna position fluctuation speed according to an inclination angle, and a correction speed calculation part that corrects the moving speed with the antenna position fluctuation speed to obtain a correction speed. The GPS navigation apparatus is characterized in that the corrected speed is given to the positioning result display unit instead of the moving speed. 2. The GPS navigation apparatus according to claim 1, wherein the moving body is a ship, the inclination angle detection unit measures an inclination angle with respect to a traveling direction of the ship, and the fluctuation speed calculation unit is associated with the traveling direction. A GPS navigation apparatus characterized by calculating a fluctuation speed.

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