JPH0679063B2 - Moving body position detection method - Google Patents

Description

The present invention relates to a method for detecting a position of a moving body in a navigation system for a moving body such as an automobile or a ship, and is particularly suitable for use in detecting the position of an automobile among the moving bodies. It is a thing.

(Prior Art) As shown in FIG. 5, the conventional moving body position detection method is based on N (north) based on a rotating beacon wave emitted from a fixed station A whose receiving antenna is omnidirectional and a transmitting antenna. The relative angle information (θ _A ) between the body P and the fixed station A is obtained, and further,
_A rotary beacon method has been used in which similar angle information (θ _B ) is obtained from another fixed station B and the position of the mobile body P is obtained from the intersection of these two angles θ _A and θ _B.

(Problems of Prior Art) The conventional moving body position detection method of FIG. 5 has the following problems.

(1) In order to distinguish the signals from the two fixed stations A and B, rotating beacon waves of different frequencies must be used, which is uneconomical because the required radio spectrum spreads.

(2) In the case where there are two fixed stations, if the mobile body P is on the line XX connecting the two fixed stations A and B, two angles θ _A and θ _B
Are overlapped with each other, the position detection is the same as the position detection at one angle with N (north) as a reference, and the detection accuracy is deteriorated.

(3) Since the frequencies of the fixed stations A and B are different, when the signals from the fixed stations A and B are received, the dials must be adjusted to select the stations.

(Means for Solving the Problems) An object of the present invention is to pulse code signals of two or more fixed stations to separate signals for each station, and combine pulse code signals of each fixed station with a beacon rotary. The present invention provides a moving position detecting method capable of detecting the position of a moving body based on external radio wave information.

As shown in FIG. 1, the moving position detecting method of the present invention uses two or more fixed stations A, B, ... FSK type pulse signals P ₁ , P ₂ , P having pulse codes unique to each fixed station. ₃ ... Rotate in the same rotation cycle T as cardioid directivity (second
, And the pulse signals from the fixed stations A, B ... Are transmitted with a time difference so that they do not overlap when received by the mobile unit, and the fixed stations A, B ... By detecting the pulse signal P _n of the insensitive portion O of the cardioid type directivity among the pulse signals P ₁ , P ₂ , P _3, ... Then, the angle information is calculated and the azimuth of the moving body is obtained, the position of the azimuth is obtained on the map, and the position of the moving body is detected.

(Embodiment) An embodiment of the moving body position detecting method of the present invention will be described in detail with reference to FIGS. 1 to 4.

In the present invention, two or more fixed stations A, B ... (FIG. 1) use the FSK system pulse signal P having a pulse code unique to each fixed station.
₁ , P ₂ ... (Fig. 2) are transmitted with a cardioid directivity (Fig. 2) rotating at the same rotation period (T).

As shown in FIG. ₁ , the number of pulse signals P ₁ , P _2, ... Is n (arbitrary number) within one rotation cycle of the cardioid directivity. At this time, the transmission intervals of the pulse signals P ₁ , P _2, ... (Δ
T) is as follows.

(360 ° / n) → T / n = ΔT Each pulse P ₁ , P ₂ ... Of this pulse width Δt is, for example,
It is divided into 6 as shown in Fig. 4, and each fixed station has a unique pulse code by this combination, and it is modulated by the carrier wave so that the signal corresponding to the number of divided bits can be identified by the FSK method. is there. By the way, in the case of FIG.
2 ⁶ = 64 stations can be identified.

In the present invention, when the pulse signals P ₁ , P ₂ ... Are transmitted from the fixed stations A, B.
If the transmission time difference td (FIG. 1) between the fixed stations is small, the mobile station may receive pulse signals from the fixed stations in an overlapping manner. Therefore, according to the present invention, the fixed stations A, B ... Signal is synchronized with the synchronization signal Po, and the transmission time difference td (Fig. 1) of each fixed station A, B ... Is set longer than the radio wave propagation time, and the pulse signal from each fixed station is transmitted by the mobile unit. It does not overlap when received.

Then, at a fixed station A at t = 0, an N (north) direction cardioid directivity radio wave as shown in FIG. 2 (a) is transmitted, and this cardioid directivity is shown in FIG. B)
Suppose that it is rotated by the angle θ as shown in. In this case, the sensitivity in the θ direction becomes a zero point, that is, a dead part 0 as shown in FIG. At this time, the pulse signals P ₁ , P _2, ...
The reception level of is as shown in FIGS. 3 (a) and 3 (b).

In the present invention, two or more pulses are detected by detecting the pulse (Pn in FIGS. 1 and 3) of the dead portion 0 of the pulse signals P ₁ , P ₂ ... To get the angle information from the fixed station. In this case, since the pulse signal Pn of the insensitive part 0 has a pulse interval of a cycle t (FIG. 3) which is 1 / n of the rotation cycle T of the cardioid type directivity, a plurality of pulses can be obtained by detecting this pulse signal Pn The angle information from the fixed station can be obtained. Specifically, the time t from the synchronization signal Po in FIG. 3 (a) until the cardioid directivity acyclic portion 0 is measured, and the rotation angle θ (FIG. 2B) is obtained from the following equation.

θ = 360 × (t / T) This rotation angle θ is the angle based on N (north) between the fixed station and the moving body. In this case, the number n of the pulse signals P ₁ , P _2, ... In the position rotation cycle T corresponds to the angular resolution.

In the present invention, the position of the moving body can be detected by calculating the angle information thus obtained in the same manner as in the prior art to obtain the direction of the moving body and comparing the direction on the map.

(Effect of the invention) The mobile body position detection method of the present invention provides a cardioid directivity in which FSK pulse signals having pulse codes unique to each fixed station from two or more fixed stations are rotated at the same rotation cycle T. Since the pulse signals from the fixed stations are transmitted with a transmission time difference td so that they do not overlap with each other when received by the mobile unit, the following effects can be obtained.

． Insensitive part 0 of pulse signals from two or more fixed stations
Since the angle information can be obtained from a plurality of fixed stations by detecting the pulse signal Pn of 1, the position information of the moving body can be accurately detected by processing this angle information in the same manner as in the conventional case.

． Since the pulse signals transmitted from two or more fixed stations are of the FSK system having a pulse code unique to each fixed station, the fixed stations can be identified by one frequency. Therefore, the required radio spectrum is narrow and economical.
Also, there is no hassle of adjusting the dial by tuning as in the past.

[Brief description of drawings]

FIG. 1 is a model explanatory view of transmission pulse signals of two stations by the moving body position detection method of the present invention, FIGS. 2 (a) and 2 (b) are cardioid directivity pattern explanatory views, and FIG. 3 (a). ) Is an explanatory diagram of the receiving level of the receiver, (b) is an explanatory diagram showing the receiving level of the receiver in pulses, FIG. 4 is an explanatory diagram showing an example of pulse signal division, and FIG. 5 is a conventional position It is explanatory drawing of a confirmation method. A is a fixed station P ₁ , P ₂ is a pulse signal td is a propagation time difference T is a rotation period ΔT is a pulse interval Pn is a pulse signal of a dead part t is 1 / n of the rotation period T Cycle of

Claims (1)

[Claims] 1. A FSK type pulse signal having a pulse code peculiar to each fixed station from two or more fixed stations is provided with a cardioid directivity that rotates at the same rotation period (T), and each fixed Pulse signals from stations are transmitted with a time difference (td) so that they do not overlap when received by a mobile unit, and pulses of the cardioid directivity insensitive portion of the pulse signals transmitted from each fixed station. (Pn) is detected to obtain angle information from two or more fixed stations, and the angle information is processed to detect the position of the moving body.