JPH01153988A - Position detecting device - Google Patents

Abstract

PURPOSE:To detect the position of a body to be detected with high accuracy by deriving position information on the object body from received signal information received from the object body and pieces of position information on a moving body and a satellite. CONSTITUTION:An underwater sensor 11 surveys an underwater body by a target detection sensor 115 and sends information on it to a transmitter 114 through a controller 111. A receiving antenna 112, on the other hand, receives L-band GPS signals from GPS satellites 13 and 13' and the received signals are converted by a frequency converter 113 to an S band and then sent to the transmitter 114. Then the transmitter 114 composes one signal of the S-band GPS signals and target detection signal and the composite signal is sent out by a transmitting antenna 116. A mother machine 12, on the other hand, receives L-band GPS signals from the satellites 13 and 13' by an L-band receiver 123 through a receiving antenna 12 and also receives the sent signal of the sensor 11 by an S-band GPS receiver 124 through a receiving antenna 122. Then demodulated data of the receivers 123 and 124 are sent to a computer 124 to find the position of the sensor 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a position detection device for detecting the position of an underwater object such as a submarine or a school of fish.

(Prior Art) Underwater sensors have conventionally been used as devices for detecting underwater objects such as submarines and schools of fish. This underwater sensor uses acoustics, magnetism, etc. - An example is a sonobuoy. Such an underwater sensor is, for example, one that is dropped and deployed from an aircraft (mother aircraft), and has a function of detecting objects in the water and reporting the detected information to the mother aircraft.

However, in order to know the position of the underwater sensor as described above, it is necessary to visually recognize the underwater sensor on the mother machine side or to detect the position using radar or the like. In order to improve position detection accuracy, it is also required that the mother machine pass directly above the underwater sensor. This limits the range of action of the mother aircraft, limits its flight pattern, and limits its search area. In particular, radar has many problems because the position detection accuracy of underwater sensors is limited and it is difficult to distinguish objects from other objects.

(Problems to be Solved by the Invention) As described above, conventionally there has been no effective means for accurately detecting the position of an object to be detected, such as an underwater sensor, from a remote position.

This invention was made to solve the above problem.
The present invention aims to provide a position detection device that is small and inexpensive without using radar, and can detect the position of an object with high precision at a distance from the object without relying on visual inspection.

[Configuration of the Invention (Means for Solving the Problems) In order to achieve the above object, a position detection device according to the present invention is mounted on a moving object, receives signals from a satellite, and determines the position of the moving object and the satellite. a first processing means for deriving information; a second processing means mounted on the object to be detected and receiving a signal from the satellite, converting the frequency and transmitting the signal; deriving means for receiving a signal transmitted from a second processing means and deriving position information of the second processing means from received signal information and position information of the mobile object and the satellite. .

(Function) The position detection device with the above configuration receives a signal from a satellite at the detected object, converts the frequency, and sends out the signal, and the moving object receives the signal from the satellite to obtain position information of the moving object and the satellite. At the same time, the signal transmitted from the object to be detected is received, and the position information of the object to be detected is derived from the received signal information and the position information of the mobile object and the satellite.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

Figure 1 shows its configuration, where 11 is an underwater sensor;
2 is a signal processing device mounted on the mother aircraft (aircraft, ship, etc.), and 13.13' is a GPS (Gronacle Positioning System) satellite. This satellite 13, 13'
may be a satellite of another system, or may be a single satellite, but here we will explain the case where a GPS satellite is used.

The underwater sensor 11 is totally controlled by a controller 111, and a receiving antenna 112 receives a signal (L band = 1575.42M) from a GPS satellite 13.13'.
Hz and 1227.80 MHz are carrier waves. Hereinafter, it will be referred to as a GPS signal. ) is received by the frequency converter 113.
After converting the signal into another different frequency band (for example, S band), the signal is sent to the transmitter 114. Further, this underwater sensor 11 has an underwater target detection sensor 115 that uses acoustics, magnetism, etc., and sends information obtained by this sensor 115 to a transmitter 114 via a controller 111. Then, the transmitter 114 synthesizes the frequency-converted GPS signal and the target detection signal,
The signal is transmitted from a transmitting antenna 116.

The signal processing device 12 receives GPS signals from GPS satellites 13 and 13'.
A receiving antenna 121 that receives the S signal and an underwater sensor 1
Each antenna 121 , 122 has a receiving antenna 122 that receives a signal from 1 (hereinafter referred to as a sensor signal).
The signals obtained by the respective L-band GPS receivers 123
, the S-band GPS receiver 124 detects the signals, and sends each signal to the computer 125. This computer 125 uses the received GPS
The position of the self (mother machine) and the position of the underwater sensor 11 are calculated from the signals and sensor signals, and each position information obtained here is sent to a display (not shown) and displayed.

GPS satellites 13 and 13' are satellites developed for detecting the position of mobile objects, and each uses spread spectrum technology to transmit unique PN code information, position information of the satellite itself, and transmission time information of this position information. Transmit as a GPS signal.

Here, to briefly explain the position detection means using GPS, the GPS receiver installed in the moving body uses the PN code information included in each GPS signal and the PN code registered in advance.
Each data is demodulated by matching with the code information.

This demodulated data includes signal transmission time information from the satellite, so this demodulated data and the PN obtained by the receiver
The reception time of each GPS signal can be detected by adding it to the delay time data necessary for code information matching. Therefore, if we detect the radio wave propagation time from the satellite to the mobile object, that is, the distance from the satellite to the mobile object, and obtain this distance information and the satellite's own position information in the demodulated data for each satellite, it is possible to The position of a moving object can be detected.

In the above configuration, the position detecting means will be explained below with reference to FIG.

First, in the underwater sensor II, the target detection sensor 115 searches for an underwater object, and when an object is detected, the controller 111 sends the information to the transmitter 114 .

On the other hand, the receiving antenna 112 detects the GPS satellite 13°1.
A frequency converter 113 converts each received signal into an S-band signal, and then sends it to a transmitter 114. Then, the transmitter 114 transmits the S-band GP signal.
The S signal and the target detection signal are combined and sent to the transmitting antenna 11B.
Send from.

On the other hand, the mother unit ■2 uses GPS satellite 13. It receives the low-band GPS signal from
In addition to receiving it with the band receiver 123, the underwater sensor 11
S-band GP transmission signal is transmitted through the receiving antenna 122.
It is received by the S receiver 124. And each GPS receiver 1
The demodulated data of 23 and 124 is sent to the computer 125, and the position of the underwater sensor 11 is determined by the following processing (see FIG. 2).

In Figure 2, ellipsoid A represents the mother aircraft 12 and the GPS satellite 13.
is the focal point, and the underwater sensor 11 is placed at one point 17 on the surface. The distance C and each absolute position between the base machine 12 and the GPS satellite 13 can be calculated by the computer 125 in the base machine 12 from the demodulated data of the L-band receiver 123. In addition, an L-band GPS signal sent from the GPS satellite 13 propagates to the S-band GPS receiver 124 over a distance a, is converted into an S-band signal by the underwater sensor 11, and is then further propagated over a distance X before being received. . Therefore, by analyzing the demodulated data of the S-band receiver 124 with the computer 125, the distance fia
+x can be found. Therefore, the shape and position of the ellipsoid A are determined in absolute space. Similarly, GPS satellite 1
Based on the GPS signal from 3', the mother aircraft 12 and GPS satellite 1
The shape and position in absolute space of the ellipsoid B with 3' as the focal point and the underwater sensor 11 as one point on the surface are determined.

Here, in order to obtain the spatial coordinates of the underwater sensor 11 ((x, y, z) coordinates with the origin at the center of the earth) and the clock error Δt (total of 4 unknowns), signals from at least 4 GPS satellites are required. However, since the underwater sensor 11 is located above the sea surface, one unknown quantity disappears from x2 + y2 + z2 - r2 (r: radius of the earth), and if the clock error Δt is taken as the allowable error, the number of unknowns becomes two. . Therefore, according to this position detection method, the position of the underwater sensor 11 can be detected using at least two GPS satellites. That is, G.P.
It is sufficient to find the intersection of the two ellipsoids formed by the S satellites 13 and 13'.

In order to improve this measurement accuracy, the frequency of the underwater sensor 11 is slightly shifted from the frequency of the GPS signal, and the frequency converter 11
The oscillation error of the frequency converter 113 may be corrected using the S-band GPS receiver 124 or the computer 125 of the mother unit 2. Also, L band G
Mother aircraft 12 and GPS satellite 1 obtained by PS receiver 123
3.13' position information can be used to estimate the GPS information from the underwater sensor 11 and the S-band GPS receiver 12.
4 can also facilitate tracking of the signal from the underwater sensor 11.

Here, we will discuss the points that should be considered in actual operation. First, in the underwater sensor 11, if the program of the controller 111 is set to transmit only when the target detection sensor 115 detects a target, there is no need to always transmit, which is also effective in terms of power consumption. However, even if it is desired to always track the position of the underwater sensor 12, this can be done if the underwater sensor 11 is equipped with a sufficient power source.

In addition, when it is necessary to transmit special information regarding target detection, such as a sensor identification number, the frequency converter 113
It is also possible for the transmitter 114 to further modulate and transmit the converted GPS signal with some code, or to transmit the information at a frequency slightly shifted from that of the GPS signal. Incidentally, sending and receiving the sensor identification number described above is extremely effective since it is possible to manage a plurality of underwater sensors at the same time.

Therefore, if the position detection device with the above configuration is used,
Since the GPS signal is frequency-converted and sent on the underwater sensor 11 side, the position of the sensor 11 can be detected with high accuracy by the base device 12 located at a distance from the underwater sensor 11. In this case, the underwater sensor 11 can be kept small and lightweight, and can be realized at low cost.

In the above embodiment, the GPS signal received by the underwater sensor 11 is demodulated on the mother unit 12 side.
It can also be implemented by installing a PS receiver, calculating the distance and position on the underwater sensor 11 side, and transmitting the information. However, although this configuration eliminates the need for the frequency converter 113, it is equipped with a GPS receiver that is more expensive, requires more calculations, and has a larger volume and weight.
1 is disadvantageous in terms of size and weight and is often used in large numbers, so the above embodiment is economically advantageous.

[Effects of the Invention] As described above, the present invention provides a position detection device that does not use radar, is small and inexpensive, and can detect the position of an object with high accuracy at a distance from the object without relying on visual inspection. can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a position detection device according to the present invention, and FIG. 2 is a diagram for explaining position detection means of the embodiment. 11... Underwater sensor, 111... Controller, 112...
...Receiving antenna, 114...Transmitter, 115...
Target detection sensor, tte...transmission antenna, 12...
・Signal processing device, 121...L band receiving antenna,
122...S band receiving antenna, 123...L band GPS receiver, 124...S band GPS receiver, 125...computer, 13.13'...GPS satellite. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] a first processing means mounted on a moving object to receive a signal from a satellite and derive position information of the moving object and the satellite; and a first processing means mounted on a detected object to receive a signal from the satellite and frequency-convert the signal. a second processing means for transmitting a signal, and a second processing means installed in the mobile body and receiving the signal transmitted from the second processing means, and performing the second processing from the received signal information and the position information of the mobile body and the satellite. A position detection device comprising derivation means for deriving position information of the means.