WO2021220419A1

WO2021220419A1 - Positioning system, control device, positioning method, and program

Info

Publication number: WO2021220419A1
Application number: PCT/JP2020/018163
Authority: WO
Inventors: 誠史吉田
Original assignee: 日本電信電話株式会社
Priority date: 2020-04-28
Filing date: 2020-04-28
Publication date: 2021-11-04
Also published as: JP7380857B2; JPWO2021220419A1

Abstract

Provided is a positioning system which is provided with a plurality of nodes that operate as reference stations in carrier phase positioning, wherein: the plurality of nodes constitute a path including the top node and one or more nodes which are sequentially subordinate to the top node; each of nodes other than the top node in the plurality of nodes uses the immediately upper node thereof as a reference station to carry out carrier phase positioning; position information obtained as a result of carrier phase positioning in each node is transmitted to the immediately lower node thereof together with observation data of GNSS satellite signals which have been received in that node; and a mobile station uses the bottom node in the plurality of nodes as a reference station to carry out carrier phase positioning.

Description

Positioning systems, control devices, positioning methods, and programs

The present invention relates to a technique for measuring the position of a mobile station with high accuracy.

In recent years, positioning by the navigation satellite system, GNSS (Global Navigation Satellite System) has been utilized in a wide range of applications.

In the GNSS carrier phase positioning method (or GNSS interference positioning method: hereinafter, carrier phase positioning), the mobile station receives a plurality of GNSS satellite signals (hereinafter, satellite signal receiver) received by its own GNSS satellite signal receiver (hereinafter, satellite signal receiver). , Satellite signal) observation data, satellite signal observation data received by the satellite signal receiver at a fixed station (reference station) whose position is located at a known reference point, and movement using the position information of the fixed station (reference station). In order to calculate the relative displacement (baseline vector) of the station with respect to the fixed station, the baseline analysis by the carrier phase positioning calculation (hereinafter referred to as the carrier phase positioning calculation) is performed. Here, the observation data is information on the result of pseudo-distance and carrier phase phase measurement in the signal processing of the satellite signal receiver, and is also called Raw data (raw data). In the following description, the observation data shall include information necessary for positioning (information included in the navigation message, etc.) obtained by receiving the satellite signal. As the carrier phase positioning method, for example, a real-time kinematic method is used.

In carrier phase positioning, the convergence (Fix) rate of carrier phase positioning deteriorates in an urban canyon reception environment where a structure exists around the reception position of the satellite signal, and as a result, the positioning accuracy of the mobile station deteriorates. In particular, when the linear distance between the mobile station and the reference station (called the baseline length) is long, the deterioration tends to be large.

For the mobile station, it is desirable to select a reference station having a short baseline length and having highly reliable position information (position information is managed with high reliability), but a reference station having highly reliable position information As an example, the electronic reference points are not arranged at a geographically sufficient density, so that there is a problem that it is difficult for the mobile station to select an appropriate reference station.

The present invention has been made in view of the above points, and even when electronic reference points and the like are not densely arranged, higher positioning accuracy can be achieved by selecting a more appropriate reference station in which a mobile station exists in the vicinity. It is an object of the present invention to provide a method for realizing carrier phase positioning that can be obtained.

According to the disclosed technology, it is a positioning system including a plurality of nodes that operate as a reference station in carrier phase positioning.
The plurality of nodes form a path consisting of a top-level node and one or more nodes sequentially subordinate to the top-level node.
Each node other than the highest node in the plurality of nodes performs carrier phase positioning using the one higher node as a reference station.
The position information obtained as a result of carrier phase positioning at each node is transmitted to the next lower node together with the observation data of the GNSS satellite signal received at that node.
A positioning system is provided in which a mobile station uses the lowest node among the plurality of nodes as a reference station to perform carrier phase positioning.

According to the disclosed technology, even when the electronic reference points and the like are not densely arranged, the mobile station can select an appropriate reference station and perform subordinate carrier phase positioning via a plurality of reference stations.

It is a figure for demonstrating the example of the carrier phase positioning using one reference station. It is a figure which shows the example of the system configuration in embodiment of this invention. It is a figure which shows the example of the case of constructing a path autonomously. It is a figure which shows the example of the case where a path is constructed by a control device. It is a figure which shows the functional configuration example of a node. It is a flowchart which shows the operation example of an intermediate reference station. It is a block diagram of a control device. It is a figure which shows the hardware configuration example of the apparatus.

Hereinafter, an embodiment of the present invention (the present embodiment) will be described with reference to the drawings. The embodiments described below are merely examples, and the embodiments to which the present invention is applied are not limited to the following embodiments.

In the present embodiment, a station arranged at a reference point used for carrier phase positioning by a mobile station is referred to as a "reference station". In addition, the object to be positioned (the one whose position is unknown) is called a "mobile station".

The reference station may be a fixed station fixed to the ground or the like, or may be a moving mobile body (Moving Base Station). Hereinafter, when it is clearly stated that the reference station is a fixed station, it may be described as a reference station (fixed station), and when it is clearly stated that the reference station is a mobile body, it may be described as a reference station (mobile body).

In the following, a positioning system consisting of a master reference station, an intermediate reference station, a mobile station, etc. will be described, but the master reference station, the intermediate reference station, the mobile station, etc. are collectively referred to as a "node".

(Outline of Embodiment)
First, FIG. 1 shows a configuration example of an existing carrier wave phase positioning that does not have an intermediate reference station for comparison with the configuration according to the present embodiment. In the configuration example shown in FIG. 1, the mobile station 20 performs carrier phase phase positioning using a reference station 10 selected from a plurality of reference stations geographically dispersed.

The mobile station 20 selects, for example, the reference station 10 having the shortest baseline length from a plurality of reference stations, but the baseline length may not be sufficiently shortened depending on the arrangement density of the reference stations. In addition, the reception state of satellite signals at either or both of the reference station 10 and the mobile station 20 may not be good. In these situations, the mobile station 20 may not be able to obtain a convergent (Fix) solution for carrier phase positioning. If only the float solution or the differential (DGNSS) solution can be obtained without obtaining the convergence (Fix) solution, the accuracy of the position information as the positioning solution is low.

Even if a convergence (Fix) solution is obtained, if the position accuracy of the reference station 10 is low, the position accuracy obtained as a result of the carrier phase positioning operation (baseline length analysis) at the mobile station 20 is also low. However, in the prior art, since the mobile station 20 cannot know the position accuracy of the reference station 10, whether the positioning result by the carrier phase positioning using the reference station 10 selected by itself is reliable and its reliability. I couldn't know the degree of sex.

If the reference station 10 is an electronic reference point, it can be seen that the position accuracy of the reference station 10 is high, but since the electronic reference points are not geographically sufficiently densely arranged, the mobile station 20 uses the electronic reference point as the reference station. It is assumed that there are many cases where selection is not possible.

From the above viewpoint, in the present embodiment, the mobile station performs subordinate carrier phase positioning via a plurality of reference stations. That is, the reference station whose absolute position is strictly controlled is set as the master (parent) reference station, and one or more intermediate reference stations for positioning directly or indirectly subordinate to the master reference station are provided, and the master reference station is provided. And the one or more intermediate reference stations form one path to the mobile station. A fixed station is usually used as the master reference station, and an electronic reference point or the like is applicable.

Here, "subordinate" means a relative relationship in which an intermediate reference station is a mobile station (position is unknown) that performs carrier phase positioning using a reference station (position is known). In this case, the intermediate reference station that is the mobile station is said to be "subordinate" to the intermediate reference station (or master reference station) that is the reference station, and this relationship goes back to one or more reference stations. In other words, the intermediate reference station to which it is "subordinate" is also "subordinate" to other intermediate reference points to which it is "subordinate". The position accuracy of the intermediate reference point depends on the position accuracy of the "subordinate" intermediate reference station (or master reference station).

The mobile station performs carrier phase positioning using the lowest intermediate reference station among one or more intermediate reference stations. Further, one mobile station is subordinate to one master reference station via one or more intermediate reference stations. The "path" may be formed between the master reference station and the lowest intermediate reference station, or may be formed between the master reference station and the mobile station using the lowest intermediate reference station. You may.

One or more intermediate reference stations are reference stations selected from a plurality of geographically dispersed reference stations. The intermediate reference station may be a fixed station or a mobile (Moving Base Station). That is, a mobile station that performs carrier phase positioning using a certain intermediate reference station may be an intermediate reference station for another mobile station.

(Example of positioning system in this embodiment)
FIG. 2 shows an example of a positioning system that forms the above path. The positioning system shown in FIG. 2 includes a master reference station 100, an intermediate reference station 101, an intermediate reference station 102, an intermediate reference station 103, and a mobile station 200, and one path is formed by connecting these nodes. The term "connection" here means that one node becomes a reference station (a node whose position is known) and the other node uses the reference station to perform carrier phase positioning (a node whose position is unknown). It means that there is a relationship of becoming. More specifically, the upper (reference station) node and the lower (mobile station) node are connected by a communication network, and the upper (reference station) node to the lower (mobile station) node via the communication network. , Observation data, location information, and other information detailed below are transmitted.

The master reference station 100 is the highest reference station, and as described above, for example, it is a reference point such as an electronic reference point whose position (coordinates) is strictly controlled.

Each intermediate reference station, which is a reference station other than the master reference station 100, uses an intermediate reference station closer (upper) to the master reference station as a reference station, and sets itself as a mobile station (station whose position is unknown). Perform the operation. "Closer to the master reference station" means that the number of hops to the master reference station is smaller. For example, in the positioning system of FIG. 2, the intermediate reference station 101 having one hop to the master reference station 100 is closer to the master reference station 100 than the intermediate reference station 102 having two hops to the master reference station 100. In this embodiment, an upper limit may be set for the number of intermediate reference stations (that is, the number of hops) that can be subordinate to the master reference station 100.

In the example of the positioning system of FIG. 2, the intermediate reference station 101 performs carrier phase positioning using the master reference station 100, the intermediate reference station 102 performs carrier phase positioning using the intermediate reference station 101, and the intermediate reference station 103 performs carrier phase positioning. The carrier wave phase positioning is performed using the 102, and the mobile station 200 performs the carrier wave phase positioning using the intermediate reference station 103.

(About the information sent from the upper node to the lower node)
Each of the master reference station 100 and the intermediate reference stations 101 to 103 has its own position information (coordinate values), observation data obtained from its own received satellite signal, and information on its own positioning status, which is one node below ( Send to the direct lower node). The one lower node can perform the carrier phase positioning operation using the position information and the observation data received from the one higher node (direct upper node).

The position information of the node itself is the result of the carrier phase positioning operation in the node using the direct upper node as the reference station. However, regarding the master reference station 100 (electronic reference point or the like), the direct lower node may acquire the position information of the master reference station 100 from the server or the like that manages the master reference station 100 (electronic reference point or the like).

<How to send information>
Each node does not have to transmit the position information, the observation data, and the information regarding the positioning state at the same timing. For example, the position information may be transmitted only when the position information changes by a predetermined threshold value or more. The position information, the observation data, and the information on the positioning status may all be transmitted directly from the upper node to the lower node directly via the network, or may be transmitted via the server on the network. May be good. That is, the higher-level node may send the information to the server, and the server may send the information to the directly lower-level node of the higher-level node.

<Information on positioning status>
The information on the positioning status includes, for example, traceability information on positioning accuracy, the carrier phase positioning status (convergence (Fix), Float, DGNSS, positioning impossible), and carrier phase positioning at the node on which the carrier phase positioning is performed. Any one, any two, or all of the information indicating the reliability of the node. Note that the traceability information regarding the positioning accuracy may also serve as information indicating the reliability of the node that has performed the carrier phase positioning. Hereinafter, each information regarding the positioning state will be described.

<Traceability information on positioning accuracy>
The traceability information regarding the positioning accuracy that a node sends directly to the lower node is, for example, the convergence (Fix) solution of the carrier phase positioning in all the nodes from the master reference station, which is the highest node for the node, to the node. It is information indicating whether or not it has been obtained.

However, when the position information of the master reference station is acquired from the server that manages the master reference station (electronic reference point, etc.), the "traceability information regarding positioning accuracy" transmitted by a certain node is larger than that of the master reference station for that node. It may be information indicating whether or not a convergence (Fix) solution of carrier phase positioning is obtained in all the nodes from the intermediate reference station one lower to the node.

For example, in the example of FIG. 2, when the master reference station 100 is an electronic reference point and a convergence (Fix) solution is obtained at the intermediate reference station 101, the intermediate reference station 101 uses the electronic reference as traceability information regarding positioning accuracy. Information indicating that there is traceability to the point is transmitted to the intermediate reference station 102. When the intermediate reference station 102 that has received the information has obtained a convergent (Fix) solution, the intermediate reference station 102 transmits information indicating that there is traceability to the electronic reference point to the intermediate reference station 103.

When the intermediate reference station 103 that has received the information has obtained a convergence (Fix) solution, the intermediate reference station 103 transmits information indicating that there is traceability to the electronic reference point to the mobile station 200. Upon receiving this information, the mobile station 200 performs carrier phase phase positioning using the intermediate reference station 103, so that the mobile station 200 is in a convergent (Fix) state of carrier phase positioning from an electronic reference point whose position is strictly controlled. Carrier phase positioning can be performed using the reference station (intermediate reference station 103) that continues to be used.

Assuming that the convergence (Fix) solution cannot be obtained at the intermediate reference station 102, the intermediate reference station 102 directly provides the traceability information regarding the positioning accuracy, which indicates that the traceability to the electronic reference point is cut off. It is transmitted to the intermediate reference station 103 which is a lower node. Further, the intermediate reference station 103 transmits information indicating that the traceability to the electronic reference point is cut off to the mobile station 200 as the traceability information regarding the positioning accuracy.

Upon receiving the information indicating that the traceability to the electronic reference point is cut off, the mobile station 200 stops using the intermediate reference station 103 as the reference station, and uses the intermediate reference station belonging to another path for carrier phase positioning, for example. It can be used as an opportunity to switch the path, which is selected as the reference station to be used. An example of the selection method will be described later.

<Status of carrier phase positioning>
The state of carrier phase positioning transmitted by a node directly to a lower node is, for example, FIX (information indicating that a convergent (Fix) solution has been obtained), FLOAT (information indicating that a Float solution has been obtained), and the like. DGNSS (information indicating that a DGNSS solution has been obtained) or positioning impossible (information indicating that a positioning solution cannot be obtained).

From this information, the following nodes can know whether or not a convergence (Fix) solution has been obtained in the carrier phase positioning using the upper node directly above the direct upper node.

However, even if a certain node receives "FIX" from the direct upper node, the traceability to the master reference station is cut off as the traceability information regarding the positioning accuracy from the direct upper node. When it is received, the node that has received the information may not trust the position information of the direct higher-level node.

<Reliability information>
The reliability information that a node sends directly to the subordinate nodes is, for example, whether or not the node is a fixed station, the actual availability of the node, the quality of the network (link status, packet loss rate, propagation delay, etc.). ), Interference signal reception status, convergence (Fix) rate, cycle slip rate, etc. From these reliability information, the lower node can determine the reliability (whether or not it is accurate) of the position information obtained from the direct upper node. For example, if it is found that the reliability is lower than the threshold value, it is possible to notify the direct lower node that the reliability (or accuracy) of the carrier phase positioning using itself as a reference station is low.

The availability of a node is the probability that it will be able to receive services from that node at some point in time. In the case of this example, receiving the service means obtaining the observation data and the position information used by the lower node from the node. For example, if a node is aging and often fails, its availability will be low. In addition, even if it is a little old, if it has a dual configuration such as hot standby, the decrease in availability can be suppressed.

The "network" in the quality of the network is a network to which the nodes are connected, and the observation data and the position information obtained by the node are transmitted to the lower node via the network. If the quality of the network is low (eg, irregular link breaks, frequent packet loss, high propagation delay), the lower node may not be able to receive the observation data and location information of the upper node. Occurs. Therefore, the quality of the network should be high.

The reception status of the interference signal is, for example, when a base station of the mobile network exists near the node, the downlink signal from the base station constantly affects the satellite signal received by the node as an interference signal. In some cases. When the node receives an interference signal, the reception quality of the satellite signal received by the node deteriorates, and the phase of the carrier wave of the satellite signal may not be accurately observed. Therefore, the strength of the interference signal should be small. The influence of the interference signal strength can be reduced when the satellite signal is received by means such as mounting a frequency filter that reduces the signal outside the band of the satellite signal.

The convergence (Fix) rate is the ratio of the time spent in the convergence (Fix) state in a certain period in the past. The convergence (Fix) rate depends on the reception status of satellite signals of the node (and the node directly above the node) and the carrier phase positioning performance of the node. When the convergence (Fix) rate is high, it is assumed that the node is in a relatively good reception environment (a reception environment with a high open porosity and close to open skies), and the carrier phase positioning performance of the node is high. , It is expected that the convergence (Fix) rate will be high in the future. Therefore, when the convergence (Fix) rate is high, the reliability of the node is high. The higher the convergence (Fix) rate, the better.

Cycle slip is a temporary synchronization of the satellite signal with the carrier phase in the satellite signal receiver when a momentary interruption in the reception of the satellite signal or a momentary change in the transmission path length due to multipath occurs while the node is observing the satellite signal. This means that the phase data is interrupted and the phase data is shifted (jumped). The cycle slip rate is the rate at which cycle slip occurs. If a node has a high cycle slip rate, that node is unreliable. The lower the cycle slip rate, the better.

The operation example of a certain node (assuming that it is an intermediate reference station) regarding traceability information related to positioning accuracy will be described below.

(Operation example 1)
The node determines traceability information regarding positioning accuracy based on its own reliability information and carrier phase positioning information, and notifies the traceability information directly to the lower node. Further, the traceability information regarding the positioning accuracy may be, for example, simple information indicated by "0" or "1". Here, "0" is information indicating that the traceability to the master reference station is cut off, and "1" is information indicating that there is traceability to the master reference station.

Upon receiving "0" (information indicating that traceability to the master reference station has been cut off) from the direct higher-level node, the node concerned has the state of carrier phase positioning using the direct higher-level node and its own reliability. Regardless of the information, "0" (information indicating that traceability to the master reference station has been cut off) is notified directly to the lower node.

The node that received "1" (information indicating that it has traceability to the master reference station) from the direct upper node has the carrier phase positioning state of FIX using the direct upper node and owns itself. If the reliability is, for example, better than the threshold value, "1" (information indicating that there is traceability to the master reference station) is notified directly to the lower node.

The node that received "1" (information indicating that it has traceability to the master reference station) from the direct superior node "is in the state of carrier phase positioning using the direct superior node is FIX, and is itself. If the reliability of is not better than the threshold, for example, "0" (information indicating that the traceability to the master reference station is cut off) is notified to the direct lower node.

If it is presumed that the acquisition of FIX occurs when the reliability is high, the reliability may not be used as described below.

That is, in this case, the node that has received "1" (information indicating that it has traceability to the master reference station) from the direct upper node has the carrier phase phase positioning state using the direct upper node FIX. For example, "1" (information indicating that there is traceability to the master reference station) is notified directly to the lower node. Further, the node that has received "1" (information indicating that it has traceability to the master reference station) from the direct higher-level node has "1" (information indicating that there is traceability to the master reference station), unless the state of carrier phase positioning using the direct higher-level node is FIX. 0 ”(information indicating that traceability to the master reference station has been cut off) is notified to the direct lower node.

In addition, when the node of interest is the intermediate reference station of the mobile body, if the state of the carrier phase positioning using the direct upper node is not FIX, the node immediately responds to the direct lower node by itself. Send information that tells you "Not available (Do not Use)". The node that receives the information that conveys "Unavailable (Do not Use)" stops the carrier phase positioning using the moving body, and at the same time, transfers the information that conveys "Unavailable (Do not Use)" to the lower node directly. Notify against. Note that this operation may be performed regardless of the type of node (mobile or fixed station).

(Operation example 2)
In operation example 2, it is assumed that the node of interest is an intermediate reference station of a fixed station.

The node determines traceability information related to positioning accuracy based on its own reliability information and carrier phase positioning information, and notifies it directly to the lower node. Further, as in the operation example 1, "0" is information indicating that the traceability to the master reference station is cut off, and "1" is information indicating that the traceability to the master reference station is present. ..

The node receives "1" (information indicating that it has traceability to the master reference station) from a direct higher-level node, and then "0" (indicates that traceability to the master reference station has been cut off). Information) is received.

When the node receives "1" (information indicating that it has traceability to the master reference station), the convergent (Fix) solution (own own) obtained by carrier phase positioning using a direct higher-level node. Position information) is held. When the node receives "0" (information indicating that traceability to the master reference station has been cut off) from a direct higher-level node, it together with "0" (information indicating that traceability to the master reference station has been cut off). , Position information held, observation data, carrier phase positioning status using direct upper node (FIX or not, etc.), own reliability information including own fixed station directly Send to the subordinate nodes of.

As for the direct lower node, if the reliability of the direct upper node which is a fixed station at the time when the convergence (Fix) solution is obtained is sufficient, the obtained position information can be regarded as reliable, for example, directly. Sends traceability information (this is referred to as "2" here) indicating that "traceability to the master reference station is cut off, but traceability to a reliable fixed station is provided" to the subordinate nodes of. ..

A node that receives "2" from a direct higher node has "2" if the state of carrier phase positioning using the direct higher node is FIX and its reliability is, for example, better than the threshold. (Information indicating that there is traceability to a reliable fixed station) is notified directly to the subordinate nodes.

A node that receives "2" from a direct higher node is not "the state of carrier phase positioning using the direct higher node is FIX, and its reliability is not better than the threshold, for example". Notify "0" (information indicating that there is traceability to the master reference station) directly to the lower node.

Assuming that obtaining FIX is highly reliable, reliability may not be used as described below.

That is, in this case, the node that receives "2" from the direct upper node has "2" (traceability to a reliable fixed station) if the state of carrier phase positioning using the direct upper node is FIX. Information indicating that there is) is notified to the direct lower node. In addition, the node that received "2" (information indicating that there is traceability to a reliable fixed station) from the direct upper node must be in the state of carrier phase positioning using the direct upper node unless it is FIX. Notify the direct lower node of "0" (information indicating that traceability has been cut off).

(How to build a path)
The path connecting the master reference station, one or more intermediate reference stations, and the mobile station may be set by a manual operation to set a higher node in each intermediate reference station and the mobile station, or may be set automatically. When it is set automatically, it may be constructed by the autonomous operation of each node, or information is collected from each node that becomes a master reference station, one or more intermediate reference stations, and a mobile station via a network. A capable control device 300 may determine the path and notify each node of the direct higher-level node. Hereinafter, an example in which a path is constructed by the autonomous operation of each node will be described as a path construction method example 1, and an example in which the control device 300 constructs a path will be described as a path construction method example 2.

<Example of path construction method 1>
Example 1 of the path construction method will be described with reference to FIG. Here, it is assumed that there are three nodes, node 100 is a node serving as a master reference station, node 101 is a node serving as an intermediate reference station, and node 200 is a mobile station. Further, it is assumed that the node 100 knows in advance that it is a node that can be a master reference station. That is, the node 100 does not need to search (select) the reference station. The node 101 may be a fixed station or a mobile body.

It is assumed that each node other than the node 100 collects and holds the information necessary for selecting its own direct superior node as the reference station from each of the other nodes. This information may include information for identifying the "domain" of the reference station. A "domain" is used, for example, to identify the administrator of a reference station when a node selects a reference station in order to configure a path with reference stations of the same operator. In addition, the access authority to the information of the node may be managed.

The state shown in (a) is a state in which a connection relationship does not yet exist. First, the node 101 determines the direct upper node as the node 100 based on the collected information of the node 100 and the information of the node 200. This state is shown in (b).

At the time of (b), the above-mentioned operation (notification of information on positioning from the upper node to the lower node, etc.) is performed, and the node 200 also uses that information when directly selecting the upper node. can do.

For example, the node 200 has information that a convergent (Fix) solution has been obtained by carrier phase positioning using a higher-level node (node 100) obtained from the node 101 (information that it has traceability to the master reference station), and , The reliability of the node 101 is high, and the baseline length between the node 101 and the node 101 is sufficiently short compared to the baseline length between the node 100 and the node 101. decide. As a result, the path shown in (c) is constructed. By repeating such an operation, a longer path can be constructed.

If the node 101 fails, the node 200 detects the failure and selects another node as a direct upper node. In this way, when each node detects that the upper node has failed, it autonomously selects another node, so that the path is autonomously switched dynamically.

<Path construction method example 2>
Example 2 of the path construction method will be described with reference to FIG. In the path construction method example 2, the control device 300 is provided. The control device 300 can communicate with each node via a communication network such as a mobile network or the Internet.

Here, too, there are three nodes, node 100 is a node serving as a master reference station, node 101 is a node serving as an intermediate reference station, and node 200 is a mobile station.

For each node, the control device 300 collects information necessary for selecting a direct higher-level node as a reference station from each node (S1, S2, S3).

When the control device 300 grasps that the node 100 is the only electronic reference point, for example, the node 100 is uniquely determined as the master reference station 100.

After that, the control device 300 executes the selection process described with reference to FIG. That is, first, regarding the node 101, the control device 300 determines the direct higher-level node as the node 100 based on the collected information of the node 100 and the information of the node 200. This state is shown in FIG. 3 (b).

At the time when the selection of (b) is made, the control device 300 notifies the node 101 that the node 100 is the master reference station and the node 100 is selected as a direct superior node to the node 101.

As a result, the above-mentioned operation (notification of information on positioning from upper to lower) is performed, and the notification information is notified from the node 101 to the control device 300. The control device 300 can also use the information in selecting a direct superior node with respect to the node 200.

For example, the control device 300 has information that a convergent (Fix) solution has been obtained by carrier phase positioning using a higher-level node (node 100) obtained from node 101 (information that it has traceability to a master reference station). And, regarding the node 200, the node 101 is set to the node based on the information that the reliability of the node 101 is high and the baseline length with the node 101 is sufficiently shorter than the baseline length with the node 100. Determined as a direct superior node to 200. As a result, the path shown in FIG. 3C is constructed. By repeating such an operation, a longer path can be constructed.

If the node 101 fails, the control device 300 detects the failure and selects another node as a direct superior node to the node 200. In this way, when the control device 300 detects that any of the nodes constituting the path has failed, it selects another node for the node that used that node as the higher-level node, so that the path becomes It switches dynamically.

(About node selection method)
Next, an example of a method (determination criterion) in which the control device 300 selects a direct superior node (direct superior node) of a certain node (target node) will be described. The same selection method is applied when each node autonomously selects its own direct superior node.

Hereinafter, an example of a judgment criterion (judgment method) for selecting a direct upper node by the control device 300 will be described. Hereinafter, for convenience, an example in which a higher-order node is directly selected based on individual judgment criteria will be described, and then an example of a combination of judgment criteria such as scoring will be described. The information used in each of the following determination methods is collected from each node and is held by the data storage unit 330 of the control device 300.

<(Example 1) Baseline length>
In Example 1, the control device 300 selects a directly higher node of the target node based on the linear distance (baseline length) between the nodes calculated based on the position information of each node.

For example, the baseline length can be used when narrowing down the candidates, such as setting a threshold value for the baseline length and selecting one or more nodes within the threshold range. In addition, when a plurality of nodes are selected by a criterion other than the baseline length, the node having the shortest baseline length is selected from the plurality of nodes, and finally the direct upper node is determined. Baseline length can also be used for.

<(Example 2) Position accuracy>
In the carrier phase positioning of the target node, if the position accuracy of the direct upper node is low, the accuracy of the positioning solution of the carrier phase positioning of the target node is also low. Therefore, in Example 2, the control device 300 directly selects the upper node based on the position accuracy of the node.

For example, it is assumed that each node holds its own position accuracy index value (accuracy index value), notifies the control device 300 of the accuracy index value, and the control device 300 holds the accuracy index value.

As an example, the accuracy index value takes a value from 0 to 100, and the larger the value, the better (higher) the accuracy. Assuming that there are four nodes, node A, node B, node C, and node D, as candidates for direct superior nodes to the target node, the accuracy index values of each are node A = 90, node B = 85, and node C = 75. , Node D = 60.

For example, the control device 300 selects node A as the node with the best position accuracy. Alternatively, a threshold value of the accuracy index value may be set, and a node whose accuracy is equal to or higher than the threshold value may be selected. As an example, assuming that the threshold value is 80, the control device 300 selects the node A and the node B.

Regarding the setting of the accuracy index value described above, for example, when the node is an electronic reference point, a high value such as accuracy index value = 100 is set. In addition, when a node (a node other than the electronic reference point) directly refers to the electronic reference point (directly subordinate to the electronic reference point) and performs carrier phase positioning to obtain its own position information. Since the traceability to the electronic reference point is high, a high value such as accuracy index value = 90 is set.

Further, for example, a node (a node other than the electronic reference point) performs carrier wave phase positioning using "a node that obtains its own position information by performing carrier wave phase positioning depending on the electronic reference point". In the case of a node that has obtained its own position information in, the traceability to the electronic reference point is lower than in the above case, so for example, a value such as accuracy index value = 80 is set.

Further, for example, when the node is a mobile body, a lower value is usually set as the accuracy index value than when the node is a fixed station. However, the moving body is equipped with a high-precision relative positioning unit (IMU (Inertial Measurement Unit), LiDAR (Light Detection and Ranking), etc.) together with an absolute positioning unit (GNSS carrier phase positioning means), and cooperates with them. If it is possible to perform highly accurate positioning at all times by providing a mechanism for operating the unit, a higher value is set as the accuracy index value in consideration of this.

The above-mentioned accuracy index value may be set manually (manually) by the node owner, the service provider of the control device 300, or the like, or the rule as shown in the above example may be programmed. Then, the node itself or the control device 300 may automatically set the accuracy index value. Further, the accuracy index value may be set dynamically.

It is an example to use the accuracy index value as described above when directly selecting the upper node based on the position accuracy of the node. The higher the traceability to the electronic reference point, the higher the traceability to the electronic reference point, for example, according to the information on the traceability to the master reference station (electronic reference point, etc.) (how many hops are away from the electronic reference point, etc.) without using the accuracy index value ( The smaller the number of hops to the electronic reference point), the better the position accuracy may be considered and the node may be selected.

<(Example 3) Satellite signal reception status>
Basically, carrier phase positioning by the target node when the degree of coincidence between the satellite signal well received by the target node and the satellite signal well received by the direct superior node is higher than when it is low. The convergence (Fix) rate of the calculation and the accuracy of the positioning solution are high. Example 3 is an example based on such a viewpoint, and Examples 3-1 to 3-3 will be described below. In addition, Example 3-1 and Example 3-2 and Example 3-3 may be used individually, or a plurality of them (including all of them) may be applied in combination.

<Example 3-1>
In Example 3-1 the control device 300 is based on the degree of coincidence between the satellite signal well received by the target node and the satellite signal well received by another node that is a direct candidate for the superior node. Then, select the upper node directly for the target node. It should be noted that "good reception" means, for example, reception quality of satellite signals (eg, CNR (Carrier-to-Noise Ratio: carrier-to-noise ratio)) or SNR (Signal-to-Noise Ratio: signal-to-noise ratio). The ratio)) can be determined by being equal to or greater than a predetermined threshold. Hereinafter, as an example, CNR is used as the reception quality.

For example, each node transmits the received satellite signal identification information (code) and its CNR to the control device 300 as real-time information. The control device 300 directly selects a higher-level node using the information.

As an example, suppose that there are two nodes, node X and node Y, which are candidates for direct higher-level nodes, and the satellite signals received by the node X, node Y, and the target node at the CNR equal to or higher than the threshold value are (node X = S1, S2). , S3, S4, S5), (node Y = S3, S4, S5, S6, S7, S8), (target node = S1, S2, S5, S6, S7, S8).

In this case, of the node X and the node Y, the node Y has a higher degree of coincidence of the satellite signals with the target node (the number of matching satellite signals is larger), so that the control device 300 can use the node X and the node Y. Of these, node Y is directly selected as the upper node.

In the above example, the satellite signal whose CNR is equal to or higher than a predetermined threshold is used, because the satellite signal having a high CNR is a visible satellite signal (a signal that arrives directly from the GNSS satellite without being blocked by a building or the like). This is because it can be estimated that there is.

Instead of using CNR, the position information of each node that is a direct candidate for the upper node, the position information of the target node, the orbit information of each GNSS satellite, and the geospatial information of the structure around each node ( Based on the dynamic map, 3D building map, sky image information, etc.), the visible satellite signal at the current time of each node that is a candidate for the target node at the current time and the direct superior node is calculated, and based on that. You may directly select the upper node.

<Example 3-2>
In Example 3-2, the control device 300 uses a satellite signal that matches a satellite signal that is well received by the target node and a satellite signal that is well received by the node that is a direct candidate for the higher-level node. The upper node is directly selected based on the obtained DOP (Division of Precision) value. The DOP value is a value that indexes the arrangement state of satellites, and the smaller the value, the higher the positioning accuracy tends to be.

The “goodly received satellite signal” in Example 3-2 may be a satellite signal based on reception quality (CNR, SNR, etc.), or may be a position information of each node that is a direct candidate for a higher-level node. , The visible satellite signal obtained by calculation from the position information of the target node, the orbit information of the GNSS satellite, the geospatial information of the structures around each node, and the like.

As an example, suppose that there are two nodes, node X and node Y, that are directly candidates for higher-level nodes, and the satellite signals that node X, node Y, and the target node are receiving well are (nodes X = S1, S2, S4, S5), (node Y = S3, S5, S6, S7, S8), (target node = S1, S2, S3, S4, S5, S6, S7, S8).

At this time, the satellite signals that match between the node X and the target node are S1, S2, S4, and S5. The satellite signals that match between the node Y and the target node are S3, S5, S6, S7, and S8. If the DOP value in S1, S2, S4, S5 is 2 and the DOP value in S3, S5, S6, S7, S8 is 3, the control device 300 is among the node X and the node Y. Select node X directly as the superior node.

<Example 3-3>
If the degree of coincidence between the satellite type and the frequency band of the satellite signals used by the direct upper node and the target node is high, it can be expected that the accuracy of the carrier phase positioning solution of the target node is high. Therefore, in Example 3-3, the control device 300 uses the target node based on the degree of coincidence between the satellite type and frequency band used by the target node and the satellite type and frequency band directly used by each candidate node of the upper node. Select the direct upper node for.

As an example, assuming that there are two direct upper node candidate nodes, node X and node Y, the satellite type (A, B, C) and frequency band (F1, F2) used by node X, node Y, and the target node, respectively. , F3) (node X = A _F1 , B _F1 , B _F2 , C _F1 , C _F2 , C _F3 ), (node Y = A _F1 , A _F2 , A _F3 , B _F1 , B _F2 , C _F1 ), (Target nodes = A _F1 , A _F2 , B _F1 , B _F2 , C _F1 ).

In this case, of the node X and the node Y, the node Y has a higher degree of coincidence with the target node (the number of matching satellite types and frequency bands is larger), so that the control device 300 can use the node X and the node Y. Of these, node Y is directly selected as the upper node.

<(Example 4) Reliability>
It is preferable that the node used by the target node for performing carrier phase positioning has high reliability from the viewpoint of maintaining stable and high positioning accuracy than when the reliability is low.

As the reliability index, as described above, availability performance, network quality (link state, packet loss rate, propagation delay, etc.), interference signal reception status, convergence (Fix) rate, cycle slip rate, convergence (Fix) ) There are conditions, etc. These are examples, and indicators other than these may be used as reliability indicators.

Each of these pieces of information is transmitted from each node to the control device 300 as real-time information. However, information having low real-time property (for example, actual availability) may be transmitted to the control device 300 from, for example, a server that manages each node. The control device 300 selects the node with the highest reliability from the plurality of candidate nodes. Alternatively, the control device 300 selects one or more nodes whose reliability is higher than a predetermined threshold value.

The above availability results, network quality (link state, packet loss rate, propagation delay, etc.), interference signal reception status, convergence (Fix) rate, cycle slip rate, convergence (Fix) state, etc. are independent of each other. It may be used, or one index value of reliability may be obtained by combining any one or more (including all).

<Example of index usage>
For each of the above-mentioned indexes, each value or state itself may be used as a condition for directly selecting a higher-level node, or a unified index value (referred to as a reliability index value here) may be directly converted into a higher-level node. May be used to select. The conversion from each index value to a unified reliability index value may be performed manually, or may be performed automatically by determining a rule. Further, one reliability index value may be derived by combining a plurality of index values. For example, "availability x A + packet loss rate x B + interference signal strength x C + cycle slip rate x D" (A, B, C, D are predetermined constants) may be used as the reliability index value.

As an example, the reliability index value takes a value of 0 to 100, and the larger the value, the higher the reliability. Assuming that there are four nodes, node A, node B, node C, and node D, as direct candidates for higher-level nodes, the reliability index values of each are node A = 99, node B = 85, node C = 75, and node. It is assumed that D = 50.

For example, the control device 300 selects node A as the most reliable node. Alternatively, a node whose reliability index value threshold value is set and the accuracy is equal to or higher than the threshold value may be selected. As an example, assuming that the threshold value is 80, the control device 300 selects the node A and the node B.

(Example of using a combination of node selection criteria)
The control device 300 combines at least any one or more (or all) of the above-mentioned determination criteria of Examples 1 to 4 and scores them to obtain a score for the target node from among a plurality of nodes whose baseline length is equal to or less than the threshold value. You may directly select the upper node.

For example, the score S is set to "S = baseline length index value x α + position accuracy index value x β + satellite signal reception state index value x δ + reliability index value x γ" (α, β, δ, γ are predetermined constants). Calculate and select the node with the largest S. α, β, δ, and γ are determined in advance by, for example, experiments. The constant of any one or more of α, β, δ, and γ may be 0. For example, the baseline length may be used only to narrow down the first candidate, and α may be set to 0 in the above score calculation. That is, the baseline length may be excluded from the above score calculation. In addition, the combination of judgment criteria used for node selection may be changed depending on the use case.

(Device configuration example)
FIG. 5 shows a functional configuration diagram of the nodes 200 constituting the positioning system according to the present embodiment. The node 200 is assumed to be a mobile body (mobile station), but even if it is a fixed station, it has basically the same configuration.

As shown in FIG. 5, the node 200 has an information transmission / reception unit 210, a higher reference station determination unit 220, a data storage unit 230, an absolute positioning unit 240, a relative positioning unit 250, a positioning control unit 260, and an output unit 270.

The information transmission / reception unit 210 acquires the information transmitted from each of the other nodes (information necessary for directly selecting the upper node). The acquired information is stored in the data storage unit 230. In addition, the data storage unit 230 also stores the information necessary for directly selecting the upper node of the node 200 itself. In addition, the information transmission / reception unit 210 receives the observation data, the position information, and the information on the positioning status from the selected direct upper node, and transmits the observation data, the position information, and the information on the positioning status to the direct lower node.

The upper reference station determination unit 220 reads information from the data storage unit 230, and uses the read information to directly select a higher node for the node 200. The selection operation of the upper reference station determination unit 220 is the same as the selection operation of the control device 300 described above.

The absolute positioning unit 240 receives the satellite signal and performs code positioning or carrier phase positioning. The relative positioning unit 250 is a vehicle speed pulse measuring unit, an IMU, an in-vehicle camera, a LiDAR, a GNSS Doppler shift measuring unit, and the like. The vehicle speed pulse measuring device shows the speed of the vehicle, that is, the distance traveled in a unit time. A three-dimensional angular velocity and acceleration are obtained by a three-axis gyro and a three-direction accelerometer mounted on the IMU. The relative position of the vehicle can be obtained from the movement of the object in the image taken by the in-vehicle camera. In LiDAR, the distance to the object can be measured and the relative position of the vehicle can be obtained by irradiating the object with the laser beam and observing the scattered or reflected light. In the GNSS Doppler shift, the relative position can be obtained from the speed of the vehicle obtained by measuring the frequency change of the carrier wave.

The relative positioning unit 250 may be a plurality of positioning means among positioning means such as a vehicle speed pulse measuring machine, an IMU, an in-vehicle camera, a LiDAR, and a GNSS Doppler shift measuring machine, or may be one positioning means. good. When the relative positioning unit 250 has a plurality of positioning means, a mechanism may be provided for selecting and outputting the most accurate positioning result from the positioning results obtained by each of the plurality of positioning means. However, a mechanism may be provided in which all or part of the positioning results obtained by each of the plurality of positioning means are coupled by a Kalman filter or the like and output.

Further, the relative positioning unit 250 is supplied with a high-precision clock signal obtained by time synchronization with the GNSS signal from the absolute positioning unit 240. Even if the high-precision clock signal is interrupted, the relative positioning unit 250 can maintain the accuracy of the clock signal by holdover (self-propelled operation of the oscillator) regardless of the time synchronization with the GNSS signal. When the node 200 is a fixed station, the relative positioning unit 250 may not be provided.

The positioning control unit 260 switches the positioning means to the relative positioning unit 250 to perform positioning when, for example, in an urban canyon environment or the like, the absolute positioning unit 240 cannot obtain a convergence (Fix) solution. Perform continuous control. Further, the positioning control unit 260 determines the traceability to the master reference station and determines the action based on the information regarding the positioning state directly received from the higher-level node. Also, based on its own positioning result, it creates information to be sent directly to the lower node. For example, when the positioning control unit 260 receives the information for transmitting "unavailable (Do not Use)" directly from the upper node, the positioning control unit 260 transmits "unavailable (Do not Use)" directly to the lower node and another It is possible to instruct the upper reference station determination unit 220 to directly select the node as the upper node.

The output unit 270 outputs the current position, which is the positioning solution output from the positioning control unit 260, to the outside of the device. The current position is represented by (x, y, z) three-dimensional coordinates, but the output information may be the three-dimensional coordinates themselves in the geographic coordinate system or the projected coordinate system, or other information. You may. For example, a control signal may be output to the control unit of the autonomous vehicle, or image information indicating the position on the map may be output.

The node 200 may be a single physically cohesive device, or a device in which some functional parts are physically separated and a plurality of separated functional parts are connected by a network. May be good.

Further, the node 200 may include all the functions shown in FIG. 5, or even if some functions are provided on the network (for example, on the cloud) and the remaining functions are mounted on the node 200 and used. good.

For example, observation data (also called Raw data) is output from the GNSS carrier phase positioning receiver provided in the node 200, and the observation data is provided on the cloud for carrier phase positioning calculation processing via the information transmission / reception unit 210. The carrier wave phase positioning calculation may be performed on the cloud by transmitting to the functional unit. In this case, the carrier phase positioning calculation processing function unit on the cloud returns the positioning calculation result to the positioning control unit 260 via the information transmission / reception unit 210.

FIG. 6 is a diagram showing an operation example of the node 200. In S101, the upper reference station determination unit 220 directly selects the upper node. Further, here, it is assumed that there is also a directly lower node in which the node 200 is directly selected as the upper node.

In S102, the absolute positioning unit 240 directly executes the carrier phase positioning operation using the upper node. In S103, the positioning control unit 260 uses the information transmission / reception unit 210 to observe observation data, position information which is a positioning result, information on a positioning state, and information necessary for directly selecting a higher-level node (traceability information, etc.). Is sent directly to the lower node. In S104, the positioning control unit 260 directly transmits observation data, position information, information on the positioning status, and information necessary for directly selecting the upper node (traceability information, etc.) via the information transmission / reception unit 210. Receive from.

While the processes of S102 to S104 are being repeated, for example, when information for transmitting "unavailable (Do not Use)" is directly received from a higher-level node, the process transitions to START (S101) and another node is directly higher-level. Select as a node.

(Configuration example of control device 300)
FIG. 7 shows an example of the functional configuration of the control device 300. As shown in FIG. 7, the control device 300 includes an information acquisition unit 310, a path determination unit 320, a data storage unit 330, and an information providing unit 340.

The information acquisition unit 310 acquires the information transmitted from each node. The acquired information is stored in the data storage unit 330.

The path determination unit 320 reads information from the data storage unit 330 and creates a path by directly selecting a higher-level node for each node using the read information. The selection method is as described above. The information providing unit 340 transmits the information of the directly higher node selected by the path determining unit 320 to each node.

(Hardware configuration example)
FIG. 8 shows a hardware configuration example of a computer that can be used as the control device 300 or the “information transmission / reception unit 210, higher reference station determination unit 220, positioning control unit 260” of the node 200 according to the embodiment of the present invention. It is a figure which shows. The computer of FIG. 8 has a drive device 1000, an auxiliary storage device 1002, a memory device 1003, a CPU 1004, an interface device 1005, a display device 1006, an input device 1007, an output device 1008, and the like, each of which is connected to each other by a bus B. ..

The program that realizes the processing on the computer is provided by, for example, a recording medium 1001 such as a CD-ROM or a memory card. When the recording medium 1001 storing the program is set in the drive device 1000, the program is installed in the auxiliary storage device 1002 from the recording medium 1001 via the drive device 1000. However, the program does not necessarily have to be installed from the recording medium 1001, and may be downloaded from another computer via the network. The auxiliary storage device 1002 stores the installed program and also stores necessary files, data, and the like.

The memory device 1003 reads and stores the program from the auxiliary storage device 1002 when the program is instructed to start. The CPU 1004 realizes the functions related to the control device 300 or the "information transmission / reception unit 210, higher reference station determination unit 220, positioning control unit 260" of the node 200, etc., according to the program stored in the memory device 1003. The interface device 1005 is used as an interface for connecting to a network. The display device 1006 displays a programmatic GUI (Graphical User Interface) or the like. The input device 1007 is composed of a keyboard, a mouse, buttons, a touch panel, and the like, and is used for inputting various operation instructions. The output device 1008 outputs the calculation result. The display device 1006 is an example of the output unit 270.

(Effect of embodiment)
As described above, according to the embodiment of the present invention, even when the electronic reference points and the like are not densely arranged, the mobile station selects an appropriate reference station and subordinate carrier phase positioning via a plurality of reference stations. Can be done. As a result, the convergence (Fix) rate can be increased by shortening the baseline length, and the GNSS positioning performance in a non-ideal reception environment such as an urban canyon reception environment can be improved.
(Summary of embodiments)
In this embodiment, at least the positioning system, control device, positioning method, and program described in the following items are provided.
(Section 1)
A positioning system equipped with multiple nodes that operate as a reference station in carrier phase positioning.
The plurality of nodes form a path consisting of a top-level node and one or more nodes sequentially subordinate to the top-level node.
Each node other than the highest node in the plurality of nodes performs carrier phase positioning using the one higher node as a reference station.
The position information obtained as a result of carrier phase positioning at each node is transmitted to the next lower node together with the observation data of the GNSS satellite signal received at that node.
A positioning system in which a mobile station performs carrier phase positioning using the lowest node among the plurality of nodes as a reference station.
(Section 2)
Each node other than the highest-level node in the plurality of nodes transmits information indicating whether or not a convergence solution has been obtained at each node from the highest-level node to its own node to a lower-level node. The positioning system described in the section.
(Section 3)
In the carrier phase positioning using the upper node, the fixed station node in the plurality of nodes is lower than the position information when the convergent solution is obtained as its own position information when the convergent solution cannot be obtained. The positioning system according to paragraph 1 or 2 transmitted to a node.
(Section 4)
In the carrier phase positioning using the upper node, the node in the plurality of nodes transmits information indicating that the node cannot be used to the lower node when a convergent solution cannot be obtained. The positioning system according to any one of the third items.
(Section 5)
An information acquisition unit that acquires information on each node in the plurality of nodes of the positioning system according to any one of items 1 to 4.
A control device including a path determination unit that determines the path by selecting one node higher than each node based on one or more information including information other than the baseline length.
(Section 6)
A positioning method executed in a positioning system having a plurality of nodes operating as a reference station in carrier phase positioning.
The plurality of nodes form a path consisting of a top-level node and one or more nodes sequentially subordinate to the top-level node.
Each node other than the highest node in the plurality of nodes performs carrier phase positioning using the one higher node as a reference station.
The position information obtained as a result of carrier phase positioning at each node is transmitted to the next lower node together with the observation data of the GNSS satellite signal received at that node.
A positioning method in which a mobile station performs carrier phase phase positioning using the lowest node among the plurality of nodes as a reference station.
(Section 7)
A program for operating a computer as each part of the control device according to the fifth item.

Although the present embodiment has been described above, the present invention is not limited to such a specific embodiment, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It is possible. For example, in the above-described embodiment, the embodiment in which the master reference station is mainly assumed to be a fixed station in which position information such as an electronic reference point is highly managed is described, but the master reference station is a mobile body. May be good. That is, in an embodiment such as platooning, the leading vehicle is provided with means for estimating its own position with high accuracy by using LiDAR, a camera, a dynamic map, or the like, and a plurality of subsequent vehicles have a subordinate carrier phase with the leading vehicle as the master reference station. This corresponds to a usage pattern such as adjusting the distance between vehicles and the traveling lane by positioning.

10 Reference station 20 Mobile station 100 Master reference station 101-103 Intermediate reference station 200 Mobile station, node 210 Information transmission / reception unit 220 Upper reference station determination unit 230 Data storage unit 240 Absolute positioning unit 250 Relative positioning unit 260 Positioning control unit 270 Output unit 300 Control Device 310 Information acquisition section 320 Path determination section 330 Data storage section 340 Information provision section 1000 Drive device 1001 Recording medium 1002 Auxiliary storage device 1003 Memory device 1004 CPU
1005 Interface device 1006 Display device 1007 Input device 1008 Output device

Claims

A positioning system equipped with multiple nodes that operate as a reference station in carrier phase positioning.
The plurality of nodes form a path consisting of a top-level node and one or more nodes sequentially subordinate to the top-level node.
Each node other than the highest node in the plurality of nodes performs carrier phase positioning using the one higher node as a reference station.
The position information obtained as a result of carrier phase positioning at each node is transmitted to the next lower node together with the observation data of the GNSS satellite signal received at that node.
A positioning system in which a mobile station performs carrier phase positioning using the lowest node among the plurality of nodes as a reference station.
A claim in which each node other than the highest-level node in the plurality of nodes transmits information indicating whether or not a convergence solution has been obtained at each node from the highest-level node to its own node to a lower-level node. The positioning system according to 1.
In the carrier phase positioning using the upper node, the fixed station node in the plurality of nodes is lower than the position information when the convergent solution is obtained as its own position information when the convergent solution cannot be obtained. The positioning system according to claim 1 or 2, which is transmitted to a node.
A node in the plurality of nodes transmits information indicating that the node cannot be used to the lower node when a convergent solution cannot be obtained in the carrier phase positioning using the upper node. The positioning system according to any one of 3.
An information acquisition unit that acquires information on each node in the plurality of nodes of the positioning system according to any one of claims 1 to 4.
A control device including a path determination unit that determines the path by selecting one node higher than each node based on one or more information including information other than the baseline length.
A positioning method executed in a positioning system having a plurality of nodes operating as a reference station in carrier phase positioning.
The plurality of nodes form a path consisting of a top-level node and one or more nodes sequentially subordinate to the top-level node.
Each node other than the highest node in the plurality of nodes performs carrier phase positioning using the one higher node as a reference station.
The position information obtained as a result of carrier phase positioning at each node is transmitted to the next lower node together with the observation data of the GNSS satellite signal received at that node.
A positioning method in which a mobile station performs carrier phase phase positioning using the lowest node among the plurality of nodes as a reference station.
A program for making a computer function as each part in the control device according to claim 5.