JPS61235775A - Position measurement system - Google Patents

Abstract

PURPOSE:To simplify a system by mounting a repeating device on plural running bodies, and transmitting distance measurement signals to a control center (CS) through the time division of each repeating device. CONSTITUTION:Repeating devices mounted on the plural running bodies 2(2A-2D) repeat distance measurement signals which arrive from distance measurement signal generation sources (satellite) 1A-1D on time-division basis at the position of each running body 2 to transmit repetition outputs to the CS 3. Then, the CS 3 calculates the position of a corresponding body 2 on the basis of the distance measurement signals transmitted as successive repetition outputs on time-division basis to detect the positions of all the running bodies 2 on real-time basis.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a position measuring system, and in particular to a system capable of measuring the positions of a plurality of moving objects at a control station.

B. Summary of the Invention The present invention provides a position measurement system that receives ranging signals at a plurality of moving object positions and calculates the positions of the plurality of moving objects. By relaying distance signals in a time-sharing manner using each relay device and transmitting them to the control station, position data of multiple moving objects can be easily concentrated at the control station using a frequency band that is narrow enough for practical use. be.

C. Conventional technology As a system for constantly measuring the position of moving objects such as aircraft, ships, and vehicles traveling on the ground, sea, or in the air,
Conventional GPS system (Global Position
ing 5ystea+) is known. This cps
The system uses a plurality of satellites, for example four, as ranging signal generation sources, and receives information such as orbit information and clock information of each satellite from the ranging signal, which is a spread spectrum signal propagated from each satellite. By knowing the propagation time of the ranging signal between the satellite and the vehicle whose position is to be measured, the position of the vehicle can be calculated.

The spread spectrum signals used in this GPS system have an excellent feature in that they can perform highly confidential communication by using pseudo-noise code signals such as M-sequence code signals. There is an unavoidable problem that the band required for
)lz), ±1 as sideband
(MHz).

D Problems to be solved by the invention Using the GPS system with these characteristics,
If it is possible to measure the positions of multiple vehicles traveling within a designated controlled area on the sea or in the air using a real-time method, for example at a control station installed as a ground station at a designated location on the earth, it would be possible to use a variety of applications. niG
It is thought that the PS system can be applied. As a way to achieve this, GPS is installed on each vehicle, which serves as a ranging signal receiver that can measure the position based on the above-mentioned principle.
A receiver is installed on each vehicle to calculate the position of each vehicle, which changes from moment to moment as the vehicle moves, and the results of this calculation are sent to the control station via a separate transmission line between the vehicle and the control station. I think it would be a good idea to let them do so.

However, in this case, relatively complex and large ranging signal receivers must be prepared in a number corresponding to the number of moving objects, separate from the transmission path between each moving object and the control station. Therefore, there is an unavoidable disadvantage that the overall system configuration becomes large-scale.

The present invention has been made in consideration of the above points, and has n distance i
This paper attempts to propose a position measuring system that can reliably measure the moment-to-moment position of each traveling object by simply providing one No. t receiver at a control station.

E Means for Solving the Problem In order to solve this problem, in the present invention, distance measurement signal generation sources IA to ID that transmit the distance measurement signal PDT, and a plurality of traveling objects 2A, 2B...・A plurality of relay devices 11 are mounted on the top and receive the ranging signal PDT, perform frequency conversion, and then sequentially transmit the relay output S4 in a time-sharing manner, and sequentially receive the relay output S4 of the plurality of relay devices 11. A control station 3 for calculating the positions of the corresponding traveling bodies 2A, 2B, . . . is provided.

F effect The relay devices 11 mounted on the plurality of traveling bodies 2A, 2B... are configured to perform relay operations sequentially in a time-division manner, and thus distance measurement signals arriving from the generation sources IA to ID The distance measurement signal is relayed in a time-division manner at the position of each traveling object, and the relay output is transmitted to the control station 3.

The control station 3 can detect the positions of all moving objects in real time by calculating the positions of the corresponding moving objects based on the ranging signals that are sequentially transmitted as relay outputs in a time-sharing manner. .

By transmitting ranging signals from multiple relay devices to the control station 3 in a time-sharing manner in this way, it is possible to easily detect the positions of multiple moving objects using a frequency band that is narrow enough for practical use. The configuration of the position measurement system may be realized.

Embodiment G A detailed explanation will be given below with reference to the drawings as an embodiment in which the present invention is applied to a GPS system. In FIG. 1, IA,
IB, IC, and ID are satellites, and ranging signals PD each have information such as orbit information and clock information from each satellite IA to ID.
A plurality of traveling bodies 2A, 2B......T is a spread spectrum signal coded by a pseudo noise code.
is propagated to.

As shown in FIG. 2, each traveling body 2A, 2B, . . . is provided with a relay device fll, and its receiving antenna 1
2, the ranging signal PDT propagated from the four satellites IA to ID is received. Here, the ranging signal S1 received by the receiving antenna 12 is 1575.42±1
(MHz) spread spectrum signal, which is demultiplexed by the demultiplexer circuit 13 and supplied to the frequency converter circuit 14. The frequency converter circuit 14 converts the carrier frequency of the received ranging signal S1 into the transmission path to the control station 3. This converts the carrier frequency to an appropriate frequency, and lowers the carrier frequency to, for example, 500±1 (MHz) using the local oscillation output S2 generated in the separate relay device 11.

This frequency-converted output S3 is supplied to the transmitting antenna 16 via the transmission circuit 15, and the relay output S4 is thus transmitted from the transmitting antenna 16 to the control station 3 via the wireless transmission path 17.

The control station 3, as shown in FIG.
The relay output S4 transmitted from the wireless transmission path 17 is received by the receiving antenna 21 and supplied to the frequency conversion circuit 22, and the frequency of the ranging signal, that is, 1575.42, is determined by the local frequency signal S5 generated separately at the control station 3. The received signal S6 is converted into a received signal S6 having a frequency of ±1 (?fHz) and input to the ranging signal receiver 23. This ranging signal receiver 23 correlates the ranging signal PDT from each satellite IA to ID with the pseudo noise code assigned to the spread spectrum signal, thereby detecting each of the ranging signals included in the ranging signal. Information such as satellite orbit information and clock information is reproduced, and the positions of the traveling bodies 2A, 2B, . . . , which have transmitted the relay output S4, are determined by calculation.

The position data S7 obtained as a result is processed in a data processing device 24 consisting of, for example, a display, a recording device, or the like.

In this way, each of the traveling bodies 2A, 2B...... receives the ranging signal received from the satellite, and uses the relay device 11 to change the frequency of the carrier wave to a predetermined frequency (i.e., 500 [MHz)].
) directly to the control station 3.
It will be transmitted to. In this embodiment, the control station 3 sequentially designates, in a time-sharing manner, the relay device to which the relay output S4 is to be transmitted among the relay devices 11 of the respective traveling bodies 2A, 2B, . . . 2 people for each running body, 2
The control station 3 has a transmission time allocation command circuit 31 for receiving the relay outputs S4 transmitted from B, .

The transmission time allocation command circuit 31 is used for the traveling bodies 2A, 2B, . . .
Code generation circuits 32A, 32B, etc. corresponding to...
..., and in response to the clock signal S10 supplied from the timing signal generation circuit 34, the traveling bodies 2A, 2B, ...
Transmission command code signals 5IIA, 5IIB consisting of digital codes respectively assigned to...
is supplied to the switch circuit 33 from each code generation circuit 32A, 32B, . . . . The switch circuit 33 sequentially selects the transmission command code signals 5IIAS311B, . , modulates the carrier wave CR, and then sends it out to the wireless transmission path 38 through the transmission circuit 36 and further through the transmission antenna 37 as a transmission command signal S13.

Here, the frequency of the carrier wave CR is the traveling bodies 2A, 2B...
The carrier wave frequency (5
00 (MHz)) and the carrier wave frequency of the ranging signal (15
75, 42 (MHz)), and thus the transmission command signal 513 can be transmitted to each traveling body 2A, 2B, . . . without interference.

The transmission command signal S13 sent out from the transmission time allocation command circuit 31 of the control station 3 in this manner is transmitted to each traveling body 2A, 2B, . . . (FIG. 2). Each of the traveling bodies 2A, 2B, . The transmission control circuit 41 has a code determination circuit 42, and the code sent by the transmission command signal S13 is detected by each traveling body 2A, 2.
When there is a match with the code assigned to B..., this is detected and a code detection output 321 is supplied to the transmission control circuit 43. When the code detection output S21 is obtained, the transmission control circuit 43 controls the transmission circuit 15 to a transmission operation state using the transmission control signal S22,
This causes the relay operation of the ranging signal to be executed. On the other hand, when the code detection output S21 is not obtained, the transmission control circuit 43 controls the transmission circuit 15 to stop transmission, thereby controlling the relay device 11 not to perform the relay operation.

In the above configuration, each of the traveling bodies 2A, 2B... selects four satellites from among the satellites in its field of view, and transmits the ranging signal PDT arriving from each satellite to the relay device 11.
to be received. In this state, in the transmission time allocation command circuit 31 (FIG. 3) of the control station 3, the switch circuit 33 is activated for a predetermined period of time, for example, 1 (see
), the transmission command code signals 5IIASSIIB... of the code generation circuits 32A, 32B... are sequentially selected and the transmission command signal S13 is sent from the transmitting antenna 37.
Send as.

This transmission command signal S13 is transmitted to the traveling bodies 2A, 2B...
・Relay device 11 via receiving antenna 12 (Fig. 2)
The transmission command signal S13 is constantly received by the transmission control circuit 41, and when the content of the transmission command signal S13 becomes a code assigned to each traveling object 2A, 2B, etc., this is determined by the code determination circuit 42. By this, the receiving antenna 12
The transmission circuit 15 is controlled to be in a relay operation state in which the distance measurement signal PDT that is being received is sent from the transmission circuit 15 to the transmission antenna 16.

In this way, the transmission control circuits 41 of the traveling bodies 2A, 2B, etc. are sequentially designated by the transmission time allocation command circuit 31 of the control station 3 (Fig. 1), so that the Incoming ranging signal PD
T is sequentially relayed in a time-division manner by the relay devices 11 of the traveling bodies 2A, 2B, . . . , and transmitted to the control station 3.

In this way, each traveling body 2A, 2B,
The relay output S4 sequentially transmitted from . . . is received by the ranging signal receiver 23 (FIG. 3) via the receiving antenna 21 of the control station 3. Here, the ranging signal receiver 23 uses the method described below to locate the respective traveling bodies 2A, 2B, . (X, J, YLI
, Za) are calculated.

That is, the positions of the traveling bodies 2A, 2B... (XU,
The positions of satellites IA, IB, IC, ID with respect to Y, JSzo) are (X+ -Yt, Z+), (Xt, Yx, Z
X), CXS SY,, zs), (X4, Y4, Z4
), then the following four equations are established from the positional relationship between one traveling body, for example, the traveling body 2A and the four satellites IA to ID. Here, S, ~S4 are the distances from the traveling body 2A to the satellite IA. ~ Indicates the distance to ID, the following formula 8%) In formulas (5) to (8), C is the speed of light, a is the distance from the traveling body 2A to the control station 3, and T
u l-T ua is the ranging signal P from the satellites IA to ID
The clock time when DT was received, T□~T14, is the clock time when the ranging signal PDT was transmitted from the satellites IA~ID, Δ1. is the offset time between the clocks of the satellites IA to ID and the clock of the traveling object 2A.

In equations (1) 2 to (8), the unknowns are the three values Xu1
There are four values: Yu, ZU, and one value (Δtu+a/C). On the other hand, the numerical values X1, Yl % Zt, Tu
Since t~T, J4, T□~T14 are known numbers, we can finally calculate the four unknowns for equations (1) 2~(4) based on the data obtained from the ranging signals PDT of the four satellites IA-LD. Solution (possibly the position of the traveling body 2A (Xo, Y
u%Zo) can be obtained by calculation.

The above description has been about the running body 2A, but other running bodies 2
Similarly, the positions of B, 2C, . . . can be determined by calculation.

In this way, the ranging signal receiver 23 detects a large number of traveling objects 2A, 2.
By sequentially specifying each of the traveling bodies 2A, 2B, . . . by the relay output S4 transmitted from B. Therefore, even when the position of each traveling object changes, this can be detected in real time.

Therefore, by time-divisionally receiving the relay outputs S4 from a large number of moving objects into the control station 3, it is possible to commonly use the wireless transmission path 17 of the same frequency band for all moving objects. Therefore, data from a plurality of moving objects can be reliably captured using an occupied frequency band that is narrow enough for practical use. Incidentally, in a CPS system, in order to transmit a ranging signal consisting of a spread spectrum signal encoded with an 11th noise code, ±1 is required.
For example, if you try to acquire data from a large number of moving objects using a frequency division method, the frequency band as a whole will become extremely wide, making it impractical. However, such inconvenience can be effectively avoided by configuring as described above.

In addition, in the above, each traveling body 2A, 2B, old...
(sec), but this time can be changed as necessary. For example, 1 [-5ec]
It can be shortened to a certain extent. In this way, real-time performance can be further improved.

Furthermore, in the above description, each traveling body is specified one by one from the control station 3 side and the relay operation is performed, but instead of this, all the traveling bodies 2A, 2B, . . .
... may be equipped with a clock calibrated to the reference time, and the times at which relay operations should be performed may be assigned to each traveling object in advance.In this way, each traveling object 2A may be equipped with a clock calibrated to the reference time. , 2B... can concentrate the relay output S4 on the control station 3 at a predetermined time without being controlled by the control station 3, and even in this case, the same effect as in the above case can be obtained. can be obtained.

Further, in the above description, an embodiment has been described in which the present invention is applied to a GPS system using a satellite as a ranging signal source, but the source of the ranging signal is not limited to this. Even if a ground fixed station is used, it is possible to obtain a position measuring system that can easily detect the position of each traveling object in the same way as in the above case.

H Effects of the Invention As described above, according to the present invention, when position data is input from a plurality of moving objects to the control station, each moving object is relayed in a time-sharing manner sequentially for a predetermined period of time. By doing so, it is possible to realize a position measuring system with a simple configuration that only requires the use of an occupied frequency band that is sufficiently narrow for practical use.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram showing a position measuring system according to the present invention, and FIGS. 2 and 3 are block diagrams showing detailed configurations of a relay device and a control station for a traveling body. IA~ID・・・Satellite, 2A～2D・・・・・・
Running body, 3... Control station, 1
1... Relay device, 13... Branching circuit,
14... Frequency conversion circuit, 15... Transmission circuit, 23... Ranging signal receiver, 24...
...Data processing device, 31...Transmission time allocation command circuit, 32A to 32G...Code generation circuit, 33...Switch circuit, 35... Modulation circuit, 36... Transmission circuit, 41...
Transmission control circuit, 42... Code determination circuit, 43
...Transmission control circuit.

Claims (1)

[Scope of Claims] (a) A distance measurement signal generation source that transmits a distance measurement signal; (b) A distance measurement signal generation source that transmits a distance measurement signal; (c) a control station that sequentially receives the relay outputs of the plurality of relay devices and calculates the position of the corresponding traveling object. measurement system.