JP3825082B2 - Multi-point monitoring device for landslides - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a landslide multipoint monitoring apparatus.
[0002]
[Prior art]
A landslide multipoint monitoring apparatus is introduced in, for example, “Real-time Landslide Detection System Using Precise Carrier Phase GPS” (Proceeding of ION GPS-95, 1877-1884, Hitoshi Kondo).
[0003]
The following items are required for landslide monitoring.
(1) The ability to determine several locations on the ground simultaneously.
(2) These position determinations can be measured in real time.
(3) These position determinations can be measured with an accuracy of 1 to 2 cm.
(4) The deviation of the measurement point can be measured accurately and its reliability is high.
(5) It can be measured over a long period.
[0004]
For this purpose, GPS receivers arranged at several locations in the measurement area are connected together in a relay unit, connected to the interface unit via this, and further connected to the interface unit at a reference point outside the measurement area. A communication network that connects the two was developed. And the measured value of each GPS receiver is input into a computer, and it calculates.
[0005]
More specifically, a baseline (baseline length) vector is calculated in real time between each GPS receiver and the reference point GPS receiver. The deviation from the initial position is determined by the measurement result of this vector, and when it is large, it appears as an alarm on the computer screen.
[0006]
The reference point GPS receiver uses NovAtel's (AG20) (NovAtel) or ASHTECH's (Z-12) format, and the GPS receiver at each measurement point is Canada. Novatel (AG20) or Ashtech (Z-12) format is used. The relay unit is as shown in FIG. 7, and the interface unit is as shown in FIG. Note that power is supplied to each GPS receiver via an interface unit. The monitoring area by this is about 800m diameter range. In the measurement results, changes in latitude / longitude and changes in baseline (baseline length) with respect to time are shown in units of 1 cm. FIG. 6 shows an example of a conventional network.
[0007]
[Problems to be solved by the invention]
The above system has the following problems.
(1) Since existing GPS antennas and expensive GPS receivers are unitized in one-to-one correspondence, the cost becomes very high.
(2) If a landslide occurs as the number of landslide monitoring points increases, the GPS receiver is damaged along with the GPS antenna, so the loss is very large.
(3) Since the number of GPS receivers increases, the failure rate increases, which is very disadvantageous for maintenance.
[0008]
[Means for Solving the Problems]
Therefore, in the landslide multipoint monitoring apparatus according to the present invention, the GPS antennas arranged at a plurality of locations in the measurement area are connected to any one of the plurality of antenna switches, and the antenna switches are connected in cascade. Is connected to at least one first GPS receiver installed outside the measurement area via an automatic disconnection connector, and a reference GPS antenna outside the measurement area is connected to the outside of the measurement area. is connected to the second GPS receiver, by determining the deviation of the respective GPS antenna with respect to the reference GPS antenna by comparing the first GPS receiver and measurement results input to the second GPS receiver Real-time mode that continuously monitors the GPS antenna at a specific location, and precise location of all GPS antennas Measurement to performs long-term monitoring mode for calculating the movement of the ground.
[0009]
In the present invention, a GPS receiver is used for precise position measurement, but instead of having a one-to-one correspondence between the GPS receiver and the GPS antenna, a number of GPS antennas are prepared and a computer is set at regular intervals. The GPS antenna at the monitoring point is switched by the control, and many points are monitored by one GPS receiver. This method results in a system that can withstand practical use in terms of cost.
[0010]
The GPS antenna system and the GPS receiver system can be remotely operated.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Although the GPS receiver is used for precise position measurement, the GPS receiver and the GPS antenna are not made to correspond one-on-one, but many GPS antennas are prepared and monitored by computer control at regular intervals. By switching the GPS antenna at a point, many points are monitored by one or more GPS receivers (first GPS receivers) arranged outside the measurement value range (monitoring region). This method results in a system that can withstand practical use in terms of cost.
[0012]
FIG. 1 shows an overview of a monitoring system according to the present invention.
Within a measurement area (monitoring area), a plurality of antenna switches 20 connected to a plurality of GPS antennas 10 via automatic drop connectors 36 are arranged at a plurality of locations. Between each antenna switch 20, RF lines 1 and 2, SW data It is connected by a line and a power supply line.
For example, GPS antenna models 511 and 521 manufactured by Novatel, Canada or an antenna for (Z-12) manufactured by Ashtec, Inc. are suitable for the GPS antenna. For example, AG20 manufactured by Novatel, Canada is used for the GPS receiver. Z-12 from Ashtech, USA is suitable.
[0013]
One of these antenna switches 20 is connected to a plurality of GPS receivers 22 (GPS 1 and 2 in the case of illustration) via a line amplifier 24.
The antenna switch 20 is also connected to the computer 26.
[0014]
On the other hand, a GPS antenna 12 provided at a reference point outside the measurement area (monitoring area) is connected to a second GPS receiver 28 for the reference point, and the GPS receiver 28 is connected to the GPS receiver 22 (No. 1, No.2).
GPS No. 1 can communicate with the control center computer 32 via a modem 30 via a dedicated line, and GPS No. 2 communicates with the control center 32 via a modem 26 via a dedicated line. This result is output to the printer 34 and the display. The 400 MHz band is used for communication. An FMV series manufactured by Fujitsu Limited is suitable for the computer 32.
[0015]
An automatic dropout connector 36 is provided in the middle of the antenna switch and the GPS receiver line. When the distance between the antenna switch and each GPS receiver is abnormally increased, the automatic drop-off connector is removed, so there is no influence on the GPS receiver. A commercially available one can be used as the automatic dropout connector 36.
[0016]
In order to monitor a landslide in real time mode using the network shown in FIG. 1, the following procedure is adopted. The antenna to be observed is determined by the computer 32, the antenna switching time is determined in consideration of the 22 and 28 GPS specifications being used, and the measurement is automatically performed according to the order set from the computer 32. Are received and displayed by 32 computers. Depending on the situation, the antenna at a specific position is continuously monitored and its movement is displayed every moment.
[0017]
In the long-term monitoring mode, the following procedure is adopted.
Long-term monitoring mode is a method that monitors slow movements over a long period of time and tries to capture movements of several centimeters a year. In this method, the distance between the two points of the reference station antenna 12 and the GPS antenna 10 is observed by a GPS surveying method, and the position of the GPS antenna 10 is regularly measured to accurately measure the baseline length. Calculate the secular change, analyze the movement of each antenna position over the long term, and calculate the movement of the ground.
[0018]
FIG. 2 shows the measurement system according to the invention in another representation.
That is, on the mobile station side, transmissions from a plurality of GPS antennas are input to the first receiver via the antenna switching device, and transmissions from the GPS antenna at the reference point are received by the second GPS receiver. The correction information is input to the first GPS receiver. These data are input to a computer for calculation.
[0019]
3 to 5 show examples of outputs in the X direction, Y direction, and height direction in the computer.
[0020]
【The invention's effect】
(1) A large number of GPS antennas are systematically switched in a real-time mode, and a single GPS receiver is used to monitor and monitor multiple points, thereby significantly reducing costs.
(2) When a landslide actually occurs, only the GPS antenna is automatically disconnected and the GPS receiver outflow loss is eliminated, so that the loss is minimized.
(3) This system can be switched to the long-term monitoring mode when the landslide is gentle. In addition, when the landslide is sudden, it is possible to switch to the real time mode and monitor every moment.
(4) Since the monitoring point can be freely selected for each point, the entire system has flexibility. The more points, the greater the cost reduction effect.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a GPS communication network according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram showing a GPS communication network according to another embodiment of the present invention.
FIG. 3 is a graph showing X-direction deviation due to the network of FIG. 2;
4 is a graph showing a deviation in the Y direction by the network of FIG. 2;
FIG. 5 is a graph showing the deviation in the height direction by the network of FIG. 2;
FIG. 6 is an explanatory diagram showing a conventional GPS measurement system.
FIG. 7 is a circuit diagram showing an example of a circuit of the relay unit.
FIG. 8 is a circuit diagram showing an example of an interface unit.
[Explanation of symbols]
10, 12 GPS antenna 20 Antenna switch 22 GPS receiver 24 Line amplifier 30 Modem 32 Computer 36 Automatic disconnection connector

Claims (2)

GPS antennas arranged at multiple locations in the measurement area are connected to one of a plurality of antenna switches, which are connected in cascade, and one of the antenna switches located at the end is connected via an automatic disconnection connector. The reference GPS antenna outside the measurement area is connected to the second GPS receiver outside the measurement area, and the first GPS receiver is connected to at least one first GPS receiver installed outside the measurement area. Real-time continuously monitoring the GPS antenna at a specific position by determining the deviation of each GPS antenna with respect to the reference GPS antenna by comparing the measurement results input to the receiver and the second GPS receiver mode, and precisely measuring the position of all of the GPS antenna, performs long-term monitoring mode for calculating the movement of the ground Multi-point monitoring system of sliding.   The landslide multipoint monitoring apparatus according to claim 1, wherein the GPS antenna system and the GPS receiver system can be remotely operated.

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