JPH0820505B2 - GPS receiver - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a GPS receiver that receives radio waves from GPS satellites to determine the position of a reception point, and particularly to a highly accurate position from only three satellites ( The present invention relates to a device for obtaining latitude, longitude (same below) and height.

(Prior Art) A conventional GPS receiver is known as a device that receives signals from four GPS satellites and accurately measures the latitude, longitude, and height of a reception point. When such a GPS receiver is installed in an automobile etc. and travels in mountainous areas, etc., it is possible to receive only the radio waves from three satellites because it is blocked by mountains and forests along the road, and accurate measurement is possible. I couldn't.

(Problems to be solved by the invention) However, even in the measurement by three satellites, if the height of the receiving point can be separately given by some method, the position of the receiving point is accurately determined. To be This matter is known, but actually, in cars etc., the height of the receiving point is calculated separately,
It is extremely difficult to input to the GPS receiver.

(Means for Solving the Problems) In order to solve this problem, the present invention directly gives the height of the receiving point separately given when receiving the signals from three satellites and determining the position as a known number. , The data of a plurality of positions is calculated at one receiving point by changing this as an unknown number, and a virtual line (a line of the first position) of one position is first obtained. If the line of the position of the road near the receiving point (the line of the second position) is given separately from the data of the position of the road stored in ROM, and the latitude and longitude of the receiving point are obtained as the intersection of the lines of these two positions. At the same time, the height is also accurately determined, and the embodiments will be described in detail below with reference to the drawings.

(Embodiment) FIG. 1 is a block diagram showing an embodiment of the present invention, in which 1 is a GPS receiver, 2 is a height memory, 3 is a position calculator, and 4 is a CD RO.
M and 5 are indicators.

The GPS receiver 1 is the same as the conventional GPS receiver, and if the signals from the four GPS satellites are obtained, the latitude, longitude and height of the receiving point can be obtained. If only signals from three GPS satellites can be obtained, the latitude and longitude of the receiving point can be obtained by giving height data separately.

At this time, if the height data has an error with respect to the height of the true reception point, an error also occurs in the obtained latitude and longitude. For example, in FIG. 2, the true position of the receiving point is 0 (Φ,
λ, h). Φ is the true latitude of the receiving point, λ is the true longitude of the receiving point, and h is the true height of the receiving point.

Here, if an error of Δh is given to the height data separately given with respect to the true height h of the reception point, this error Δ
Errors of ΔΦ and Δλ occur in the latitude and longitude of the receiving point 0'obtained using the height data having h. The magnitude of this error is determined by the arrangement of the three GPS satellites received by the GPS receiver 1. However, if the error Δh of the height data is sequentially changed, the calculated value of the receiving point will be 0. ′
Also changes, and the locus of 0'becomes a single line passing through the true reception point 0 as shown in FIG. That is, by changing the height data, one position line (first position line) using the GPS signal is obtained.

The height data thus used is stored in the height memory 2 and sent to the GPS receiver 1. The height data stored in the height memory 2 can be increased or decreased by the position calculator 3.

The calculated latitude and longitude values obtained by the GPS receiver 1 are sent to one input terminal of the position calculator 3. Road position information is sent from the CD ROM 4 to the other input terminal of the position calculator 3. The position calculator 3 can know the latitude and longitude of each point of the road forming the shape of the road from the position information of the road sent from the CD ROM 4. The CD ROM4 is known as a large-scale memory suitable for such a purpose, and road data nationwide can be stored in one CD.

In FIG. 3, it is assumed that the position of the road sent from the CD ROM 4 to the position calculator 3 is as shown in FIG. 3 (second position line). This can be obtained, for example, by searching the corresponding part of the CD ROM using the approximate position of the receiving point by GPS as an index.
On the other hand, it is assumed that the latitude and longitude of the reception point sent from the GPS receiver 1 to the position calculator 3 are 0 '. The position calculator 3 detects that 0'is not present on the road 7, and increases or decreases the height data of the height memory 2 to obtain the line 6 of the first position. Since the initial position of the receiving point 0'is obtained by inputting arbitrary height data, it is normal that 0'does not exist on the road 7, but the receiving point on the vehicle is originally on the road 7. It should be in. That is, the latitude and longitude 0'of the receiving point sent by the GPS receiver 1 to the position calculator 3 is moved along the line 6 of the first position, and eventually the height corresponding to the position 0 of the true receiving point is reached. When the data h of the above is given to the height memory 2 from the position calculator 3, the position of the receiving point is obtained using this height data h.
The latitude and longitude 0'of the receiving point sent from the S receiver 1 to the position calculator 3 are 0, which coincides with the road 7. Therefore, the position calculator 3 detects this and sets the latitude and longitude of the 0 point as the latitude and longitude of the true reception point, and at the same time, the height data stored in the height memory 2 at the true reception point. The height of The above calculation process is automatically performed by the configuration shown in FIG.

The true latitude, longitude, and height values of the reception point thus determined are sent from the position calculator 3 to the display device 5 and displayed.

2 and 3 are explanatory diagrams showing the process of calculating the true reception point, and the display 5 displays the road 7 and the true reception point 0 and additional information (latitude of the reception point 0) on the road 7. , Longitude, height, etc.) are displayed.

(Effects of the Invention) As described above, only signals from three GPS satellites can be received, such as when traveling in a mountainous area with a car, and the receiving point constantly fluctuates in height and height. Even if it is difficult to provide the data separately, the true latitude, longitude, and height of the receiving point can be determined by using the line information of the second position such as the road position without using the height data of the map information. Since it can be obtained, there is an advantage that the time period during which the measurement accuracy deteriorates can be greatly reduced compared to the conventional GPS receiver.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram of a line at a first position with a height as a parameter, and FIG. 3 is an explanatory diagram of a process for obtaining a true reception point. is there. 1 ... GPS receiver, 2 ... Height memory, 3 ... Position calculator, 4 ... CD ROM, 5 ... Display.

Claims (1)

[Claims] 1. Data of a plurality of positions (latitude, longitude (same below)) are calculated at one reception point by receiving signals from at least three GPS satellites and changing height data to obtain 1 Means for obtaining a virtual line of the position of the book, means for giving a line of the position of the road near the reception point from the storage means of the road data, and calculation means for obtaining the position of the reception point as the intersection of the lines of these two positions A GPS receiver comprising: a display unit that displays the calculated position of the reception point.