JPH04286976A - Gps navigation device for vehicle - Google Patents

Abstract

PURPOSE:To obtain a GPS navigation device of a vehicle for detecting an accurate current position by receiving a signal electric wave from a specified number of satellites constantly regardless of mounting position of a reception antenna. CONSTITUTION:Information which is transmitted from a plurality of satellites is received by a reception antenna 1 and is applied to a GPS navigation device for a vehicle for detecting a current position of a vehicle 2. An orientation detection means 4 for detecting an advancing orientation of the vehicle 2 and a satellite selection means 3 for selecting a satellite which can receive information from a plurality of satellites based on an orbit data of a plurality of satellites, a shape of the vehicle 2 which becomes a screening portion when a satellite is acquired when viewed from mounting position of a reception antenna, and an advancing direction of the vehicle 2 which is detected by the orientation detection means 4. Information from a specified number of satellites is received constantly, thus enabling an accurate current position of the vehicle 2 to be detected.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a GPS navigation system for a vehicle that detects the current position of a vehicle by receiving signal radio waves transmitted from a plurality of satellites.

0002

[Prior Art] When driving in the suburbs with few obstacles,
There is a known GPS navigation device for vehicles that determines the combination of satellites so that signals from satellites are not often unreceivable due to obstacles when driving in mountainous areas or urban areas with many obstacles. (See 1980-198074). This GPS navigation system for a vehicle selects satellites located at high elevation angles from the horizontal direction when driving in mountainous areas or urban areas with many obstructions.

0003

[Problems to be Solved by the Invention] However, since conventional devices select satellites that are above a certain elevation angle from the horizontal direction so that they can be received, the ceiling of the vehicle may be obstructed depending on the mounting position of the receiving antenna. There is a possibility that the signal radio waves from the selected satellite cannot be received.

An object of the present invention is to provide a GPS navigation device for a vehicle that always receives signal radio waves from a predetermined number of satellites and detects an accurate current position regardless of the mounting position of a receiving antenna.

[0005]

[Means for Solving the Problems] The present invention will be explained in conjunction with FIG. 1 showing the configuration of one embodiment.The present invention is a system for receiving information transmitted from a plurality of satellites by a receiving antenna 1, and for a vehicle 2. It is applied to a vehicle GPS navigation device that detects the current position of the vehicle 2, and includes a direction detection means 4 that detects the traveling direction of the vehicle 2, orbit data of a plurality of satellites, and captures satellites as seen from the mounting position of the receiving antenna 1. Satellite selection means 3 is provided for selecting a satellite capable of receiving information from among a plurality of satellites based on the shape of the vehicle 2, which sometimes serves as a shielding part, and the traveling direction of the vehicle 2 detected by the direction detection means 4. This achieves the above objective.

[0006]

[Operation] The satellite selection means 3 selects orbit data of a plurality of satellites,
The shape of the vehicle 2 that serves as a shielding part when capturing a satellite when viewed from the mounting position of the receiving antenna 1, and the direction detecting means 4
Based on the traveling direction of the vehicle 2 detected by, a satellite capable of receiving information is selected from among the plurality of satellites. This allows information to be received from a predetermined number of satellites at all times, and accurate current position detection.

[0007] In the section of the means and effects for solving the problems described above to explain the structure of the present invention, figures of embodiments are used to make the present invention easier to understand. It is not limited to.

[0008]

Embodiment FIG. 1 shows the configuration of one embodiment. In the figure,
Reference numeral 1 denotes a receiving antenna that receives signal radio waves such as time data from a satellite, and is mounted in the trunk of the rear part 2a of the vehicle 2. 3 is a 3-channel GPS receiver,
Detect the propagation delay time of signal data from three satellites,
The distance between each satellite and the vehicle 2 is calculated by multiplying the propagation velocity of the radio wave by the correction coefficient, and the current position of the vehicle 2 is thereby detected. Further, 4 is a vehicle orientation detection device that detects the traveling direction of the vehicle 2, and is configured using a well-known geomagnetic sensor or the like. 5 is a display device that displays a map around the current location of the vehicle 2 and the detected current location. Note that when positioning is performed based on time data from multiple satellites that are located close to each other, distance detection accuracy deteriorates, so in this example, signals from three satellites that are located a certain distance apart are used. Receive radio waves and perform positioning.

When the receiving antenna 1 is attached to the trunk of the rear part 2a of the vehicle 2 or an attached device such as a spoiler as shown in FIG. 1, the ceiling of the vehicle becomes a shield when viewed from the mounting position of the receiving antenna 1. , satellites within the range of angle θ1 with respect to the horizontal direction, and within the range of angles θ2 and θ3 with respect to the vehicle traveling direction shown in FIG. 2, become undetectable. The receiver 3 is a vehicle 2 that serves as a shielding part when viewed from the installation position of the receiving antenna 1 when capturing multiple satellites.
shape data and orbit data of each satellite are stored in internal memory.

FIG. 3 is a flowchart showing the current position detection operation of the vehicle 2. In step S1, the receiver 3 reads the current time measured by an internal timer. That is, the receiver 3 measures the delay time of time data from each satellite based on this time, and calculates the distance to each satellite. In step S2, the traveling direction of the vehicle 2 is detected by the vehicle direction detection device 4. In step S3, the orbit data of each satellite is read from the memory, and in the subsequent step S4, the shape data of the vehicle is read from the memory.

[0011] In step S5, all satellites capable of receiving signal radio waves are selected based on the shape data of the vehicle, the traveling direction of the vehicle, and the orbit data of each satellite. Next, in step S6, three satellites are selected from among the selected receivable satellites according to the number of channels of the receiver 3. At this time, as described above, in order to improve position detection accuracy, satellites that are located at a certain distance from each other are selected. In the following step S7, the selected three satellites are acquired, and the signal radio waves from each satellite are received for each channel of the receiver 3. Then, in step S8, the distance to each satellite is calculated based on the propagation delay time of the signal radio wave from each satellite, and the current position of the vehicle 2 is detected based on this distance information. In step S9, from the receiver 3 to the display device 5,
The current position information is output to the vehicle 2, and the detected current position is displayed on the surrounding map of the vehicle 2.

[0012] In this way, signal radio waves are determined based on the orbit data of a plurality of satellites, the shape of the vehicle 2 which serves as a shielding part when capturing satellites as seen from the mounting position of the receiving antenna 1, and the traveling direction of the vehicle 2. Since we selected satellites that can receive , and then selected three satellites that are located far apart from each other, a part of the vehicle 2 may be blocked by the shielding part depending on the installation position of the receiving antenna 1. Therefore, the current position of the vehicle 2 can be accurately detected by constantly receiving signal radio waves from the three selected satellites.

Note that the number of channels of the receiver 3 is not limited to the above embodiment, and may be four or more channels. Further, the number of satellites to be selected is not limited to the above embodiment, and may be four or more.

In the configuration of the above-described embodiment, the vehicle direction detection device 4 constitutes the direction detection means, and the receiver 3 constitutes the satellite selection means.

[0015]

As explained above, according to the present invention, the orbit data of a plurality of satellites, the shape of the vehicle that serves as a shielding part when acquiring a satellite when viewed from the mounting position of the receiving antenna, and the traveling direction of the vehicle can be obtained. Based on this, the satellite that can receive information is selected from among multiple satellites, so regardless of the installation position of the receiving antenna, signal radio waves are always received from a predetermined number of satellites and accurate vehicle current status is determined. The location can be detected.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment.

FIG. 2 is a diagram showing a range in which satellites cannot be detected in the direction of travel of the vehicle, as viewed from the mounting position of the receiving antenna.

FIG. 3 is a flowchart showing the current position detection operation of the vehicle.

[Explanation of symbols]

1 Receiving antenna 2 Vehicle 2a　Vehicle rear 3 Receiver 4 Vehicle orientation detection device 5 Display device

Claims (1)

[Claims] Claims: 1. A GPS navigation system for a vehicle that detects the current position of a vehicle by receiving information transmitted from a plurality of satellites by a receiving antenna, comprising: azimuth detecting means for detecting the traveling direction of the vehicle; Based on the orbit data of the satellite, the shape of the vehicle that becomes a shielding part when capturing the satellite when viewed from the mounting position of the receiving antenna, and the traveling direction of the vehicle detected by the direction detecting means, A GPS navigation device for a vehicle, comprising: satellite selection means for selecting a satellite capable of receiving the information from among the satellites.