JP6162630B2 - Target positioning system and target positioning method - Google Patents

Description

  Embodiments described herein relate generally to a target positioning system and a target positioning method for positioning a target such as an aircraft.

  With the expansion of airports and the like, operation and maintenance of a target positioning system called multi-lateration (MLAT) is being promoted as support for air traffic control operations that are becoming more complicated and countermeasures for erroneous entry to the runway.

  Multilateration is the reception of signals transmitted from targets such as aircraft by multiple receiving stations (sensors) on the ground, and the difference in reception time (TOA: Time of Arrival) of each sensor This is a system for estimating the position. According to this multilateration, for example, it is possible to monitor an area (blind area) that cannot be covered by an active airport surface detection radar (ASDE).

JP 2013-44602 A

"About multi-lateration for airport monitoring", Electronic Navigation Research Institute Research Presentation (11th June 2011)

  However, in the conventional multilateration, since the target positioning accuracy depends on the arrangement of each receiving station, there arises a problem that a positioning error becomes large or a positioning result appears at a completely different position depending on the target position.

  Accordingly, an object of the present embodiment is to provide a target positioning method capable of improving the target positioning accuracy and a target positioning system using the target positioning method.

According to the present embodiment, the target positioning system includes a plurality of receiving devices, a plurality of Doppler speed calculation units, a target positioning unit, a movement speed calculation unit, and an expected area setting unit. The plurality of receiving devices receive signals transmitted at a predetermined transmission frequency from the target. The plurality of Doppler velocity calculation units, based on a difference between a transmission frequency of a signal transmitted from the target and a reception frequency of a signal received by each of the plurality of reception devices, a target Doppler viewed from each of the plurality of reception devices. Calculate the speed. The target positioning unit calculates a hyperbola between the plurality of reception devices based on a difference in reception times of signals received by the plurality of reception devices, and calculates the hyperbola between the plurality of reception devices. The target is positioned by obtaining the intersection of The moving speed calculation unit calculates the target moving speed from the plurality of Doppler speed information calculated by each of the plurality of Doppler speed calculation units. The predicted area setting unit calculates a plurality of predicted hyperboloids at the next time by adding the target moving speed calculated by the moving speed calculating unit to each of the hyperboloids between the plurality of receiving devices. The logical product of a plurality of predicted hyperboloids at the next time is set as an expected area where the target is expected to be positioned at the next time. The predicted area setting unit adds a margin to a plurality of predicted hyperboloids at the next time.

Schematic which shows the whole structure of the target positioning system which concerns on this embodiment. The block diagram which shows the structure of the target positioning system shown in FIG. Schematic which shows the target Doppler speed seen from the receiving station shown in FIG. The block diagram which shows the structure of the positioning processing apparatus shown in FIG. Schematic which shows the setting process of the prediction area by the processing operation of the positioning processing apparatus shown in FIG. The flowchart which shows the processing operation of the positioning processing apparatus shown in FIG.

  Hereinafter, a target positioning system and a target positioning method according to the present embodiment will be described with reference to the drawings.

  FIG. 1 is a schematic diagram showing an overall configuration of a target positioning system according to the present embodiment.

  The target positioning system shown in FIG. 1 receives a plurality of signals installed on the ground from a transponder (response device) 200 installed on a target O such as an aircraft via an antenna 13 (for example, a mode S signal). In this system, the target O is received from the difference in the reception time (TOA: Time of Arrival) of the mode S signal among the plurality of receiving stations. In the target positioning system of the present embodiment, the target О is measured by hyperbolic positioning. This target positioning system includes a plurality of receiving stations (sensors) A to C and a positioning processing device 4 provided in the control tower 100.

  The plurality of receiving stations A to C receive signals transmitted from the transponder 200 installed at the target O via the antenna 13.

  The positioning processing device 4 is provided, for example, in a control tower 100 that collectively manages air traffic control operations at an airport or the like, and measures the target O based on signals received by a plurality of receiving stations A to C.

  FIG. 2 is a block diagram showing a configuration of the target positioning system shown in FIG. In FIG. 2, the configuration of the receiving station A is shown as an example, and the configurations of the receiving stations B and C are the same as those of the receiving station A.

  In the target positioning system shown in FIG. 2, the receiving station A includes a receiving device 2 and a velocity component calculator 3.

  The receiving device 2 includes an antenna 11, an antenna 12, a GPS (Global Positioning System) receiver 21 and a signal receiver 22.

  The GPS receiver 21 receives a GPS signal including time information (GPS time) transmitted from a GPS satellite via the antenna 11.

  The signal receiver 22 receives the mode S signal transmitted via the antenna 13 from the transponder 200 installed at the target O via the antenna 12. The mode S signal is a signal for performing question answering collectively or individually based on an address uniquely assigned to each target O. The mode S signal received by the signal receiver 22 includes, for example, altitude information of the target O, identification information of the target O, and the like. The signal receiver 22 refers to the GPS time of the GPS signal received by the GPS receiver 21 and adds a time stamp indicating the reception time of the received signal to the mode S signal (received signal). The reception signal to which the time stamp is added is transmitted from the signal receiver 22 to the speed component calculator 3.

The velocity component calculator 3 calculates the difference between the transmission frequency (center frequency) (for example, 1090 MHz) of the mode S signal transmitted from the transponder 200 of the target О and the reception frequency of the reception signal received by the signal receiver 22. The Doppler speed Vm _x (x = A, B, C,...) Of the target O as viewed from the receiving station is calculated. Equation (1) is an example of a formula for calculating the Doppler velocity Vm _x.

The target positioning system of the present embodiment performs a process for calculating the Doppler velocity Vm _x in each of the receiving stations A through C. The Doppler speeds Vm _{A to} Vm _C information calculated by the receiving stations A to _C and the time stamp information added to the received signal are transmitted from the speed component calculator 3 to the positioning processor 4.

FIG. 3 is a schematic diagram showing the Doppler speed Vm _A of the target O as viewed from the receiving station A shown in FIG. As shown in FIG. 3, the Doppler speed Vm _A is defined as a direction in which the target OO leaves the receiving station A is +, and a direction in which the target OO approaches the receiving station A is −. Note that the directions of + and − are the same as those of the receiving station A for the Doppler speeds Vm _{B to} Vm _C of the target O as viewed from the receiving stations B to _C.

  FIG. 4 is a block diagram showing a configuration of the positioning processing device 4 shown in FIG.

  The positioning processing device 4 includes an information collecting unit 41, a target positioning unit 42, an expected area setting unit 43, and a determination unit 44.

The information collecting unit 41 collects Doppler velocities Vm _{A to} Vm _C and time stamps from the receiving stations A to _C.

  The target positioning unit 42 refers to the time stamp collected by the information collecting unit 41, calculates the difference in reception time of the received signal at each of the receiving stations A to C, and measures the target O by hyperbolic positioning. For example, when using three locations of receiving stations A, B, and C, by obtaining the intersections of the hyperbolic curves calculated between the receiving stations A and B, between the receiving stations B and C, and between the receiving stations C and A, respectively. The position T of the target O is estimated.

  The prediction area setting unit 43 predicts that the target O is expected to be positioned at the reception time (hereinafter referred to as the next time) when the reception signal transmitted from the transponder 200 is received by each of the receiving stations A to C next. Set the area. The predicted area setting unit 43 includes a moving speed calculating unit 43-1, a predicted hyperboloid calculating unit 43-2, and a margin adding unit 43-3.

The moving speed calculation unit 43-1 calculates the moving speed Vm (vector component) of the target O from the Doppler velocities Vm _{A to} Vm _C collected by the information collecting unit 41. Expression (2) is an example of an expression for calculating the moving speed Vm (vector component) of the target O, and the moving speed Vm (vector component) that satisfies Expression (2) is obtained. Incidentally, Vm _x is the direction towards the receiving station A to the target o + and to the orientation of the target o approaches to the receiving station A - to. Similarly, the receiving station B and the receiving station C are similarly formulated to solve the ternary linear equation and calculate the moving speed Vm (vector component).

  The predicted hyperboloid calculator 43-2 sets the hyperboloid calculated in the process of performing the positioning process between the receiving stations as the hyperboloid at the current time, and calculates the moving speed at each point of the calculated hyperboloid at the current time. A hyperboloid that takes into account the moving speed Vm (vector component) calculated by the unit 43-1 is calculated. The predicted hyperboloid calculator 43-2 sets the calculated hyperboloid as the predicted hyperboloid at the next time.

  The margin adding unit 43-3 adds a ± margin as coordinates to the predicted hyperboloid at the next time calculated by the predicted hyperboloid calculating unit 43-2.

  FIG. 5 is a schematic diagram showing a process of setting an expected area by the processing operation of the positioning processing device 4 shown in FIG.

  For example, as shown in FIG. 5A, the prediction area setting unit 43 uses a hyperboloid calculated in the process of performing the positioning process between the receiving stations A and B in the target positioning unit 42 as a hyperboloid at the current time. And As shown in FIG. 5B, the predicted hyperboloid calculator 43-2 is calculated by the moving speed calculator 43-1 at each point of the hyperboloid at the current time calculated by the target positioning unit 42. A hyperboloid with the moving speed Vm taken into account is calculated. This calculated hyperboloid is used as the predicted hyperboloid at the next time. Further, as shown in FIG. 5C, the margin adding unit 43-3 adds a ± margin as a coordinate to the predicted hyperboloid at the next time calculated by the predicted hyperboloid calculating unit 43-2, and sets the margin. The range of the added predicted hyperboloid is set as an area filter. The predicted area setting unit 43 calculates area filters between the receiving stations B and C and between the receiving stations C and A in addition to the receiving stations A and B, and calculates the logical product of the calculated area filters between the receiving stations. Take. The predicted area setting unit 43 sets the logical product of the area filters between the receiving stations as the predicted area in which the target O is expected to be positioned at the next time.

  The determination unit 44 determines whether the target positioning unit 42 positioned at the next time in the target positioning unit 42 is included in the predicted area set by the predicted area setting unit 43. When the next time target O is included in the set prediction area, the positioning processing device 4 outputs the positioning result of the next time to a display device or the like. When the target positioning unit 42 does not include the target OO measured at the next time in the set expected area, the positioning processing device 4 discards the positioning result at the next time and changes the processing operation to the information collecting unit. Return to 41.

  Here, the processing operation of the positioning processing device 4 in the above configuration will be described below.

  FIG. 6 is a flowchart showing the processing operation of the positioning processing device 4 shown in FIG.

As shown in FIG. 6, the positioning processing device 4 collects Doppler velocities Vm _{A to} Vm _C and time stamps from the receiving stations A to C at the information collecting unit 41 (step ST1).

  Next, the positioning processing device 4 refers to the time stamp collected by the information collecting unit 41 in the target positioning unit 42, calculates the difference in the reception time of the received signal between the receiving stations A to C, The target О is determined by hyperbolic positioning (step ST2).

Next, the positioning processing device 4 calculates the moving speed Vm (vector component) of the target O from the Doppler speeds Vm _{A to} Vm _C collected by the information collecting unit 41 by the moving speed calculating unit 43-1. (Step ST3).

  The positioning processing device 4 uses the predicted hyperboloid calculator 43-2 to move the moving speed Vm calculated by the moving speed calculator 43-1 to each point of the hyperboloid at the current time calculated by the target positioning section 42. Calculate a hyperboloid taking into account. This calculated hyperboloid is used as the predicted hyperboloid at the next time (step ST4). The positioning processing device 4 adds a margin of ± as coordinates to the predicted hyperboloid at the next time calculated by the predicted hyperboloid calculator 43-2 in the margin adder 43-3 (step ST5), and adds the margin. The range of the predicted hyperboloid is set as an area filter. The positioning processing device 4 calculates area filters between the receiving stations B and C and between the receiving stations C and A in addition to the receiving stations A and B, and calculates a logical product of the calculated area filters between the receiving stations. . The positioning processing device 4 sets the logical product of the area filters between the receiving stations as an expected area where the target O is expected to be positioned at the next time (step ST6).

  After the predicted area is set by the predicted area setting unit 43, the positioning processing device 4 performs a positioning process of the target О at the next time (step ST7). In step ST7, the positioning processing device 4 refers to the time stamp collected by the information collecting unit 41 at the next time in the target positioning unit 42, and the reception time of the received signal between the receiving stations A to C. The next time target О is determined by hyperbolic positioning.

  Here, the positioning processing device 4 determines in the determination unit 44 whether or not the target O measured at the next time by the target positioning unit 42 is included in the predicted area set by the predicted area setting unit 43 (step). ST8). When the target positioning unit 42 has positioned the target OO positioned at the next time in the predicted area (Yes in step ST8), the positioning processing device 4 outputs the positioning result at the next time to a display device or the like (step ST9) The processing operation is returned to step ST1. If the target positioning unit 42 does not include the target OO measured at the next time in the predicted area (No in step ST8), the positioning processing device 4 discards the positioning result at the next time and performs the processing operation. Return to step ST1.

  According to the above configuration, in the target positioning system of the present embodiment, the predicted area setting unit 43 sets the predicted area where the target O is expected to be positioned at the next time. As a result, even if the positioning error of the target О becomes large due to the influence of reflection or shielding by the building, the target positioning system will determine that the target О that has a large positioning error beyond the expected area range is a false detection. It is possible to reduce the positioning error to within the expected area. Moreover, even if a positioning result appears in a completely different position, the target positioning system can determine that it is a false detection because it is outside the expected area.

  Therefore, the target positioning system of the present embodiment can improve the positioning accuracy of the target O.

  Moreover, although this embodiment is implemented for multilateration (MLAT), it can be applied to wide area multilateration (WAM) having the same positioning method and MSPSR (multistatic PSR) using elliptical positioning. Is possible.

  In the target positioning system of the present embodiment, the time information is acquired from the GPS signal received by the GPS receiver 21, but the present invention is not limited to this. The target positioning system of the present embodiment may be acquired using another device that can acquire time information such as a common clock.

  In addition, in FIG. 1, as a specific example, a target positioning system in which three receiving stations A to C are arranged on the ground is shown, but even in a target positioning system in which four or more receiving stations are arranged on the ground, Good.

  The ± margin added to the predicted hyperboloid at the next time may be arbitrarily set according to the required positioning accuracy of the target О. The WAM ± margin may be set to ± 30 m, for example.

  As mentioned above, although embodiment was described, this embodiment is shown as an example and is not intending limiting the range of invention. This embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. This embodiment and its modifications are included in the scope of the present invention and the gist thereof, and are also included in the invention described in the claims and the equivalent scope thereof.

  О ... target, 100 ... control tower, AC ... receiving station, 200 ... transponder, 11-13 ... antenna, 2 ... receiving device, 21 ... GPS receiver, 22 ... signal receiver, 3 ... speed component calculator, DESCRIPTION OF SYMBOLS 4 ... Positioning processing apparatus, 41 ... Information collecting part, 42 ... Target positioning part, 43 ... Expected area setting part, 43-1 ... Moving speed calculating part, 43-2 ... Expected hyperboloid calculating part, 43-3 ... Adding a margin Part, 44 ... determination part.

Claims (2)

A plurality of receiving devices for receiving signals transmitted from a target at a predetermined transmission frequency;
A plurality of Doppler speeds for calculating a target Doppler speed viewed from each of the plurality of receiving apparatuses based on a difference between a transmission frequency of a signal transmitted from the target and a reception frequency of a signal received by each of the plurality of receiving apparatuses. A calculation unit;
Calculating a hyperbola between the plurality of receiving devices based on a difference in reception time of signals received by the plurality of receiving devices, and obtaining an intersection of the hyperbola calculated between the plurality of receiving devices; A target positioning unit for positioning the target with
A moving speed calculator that calculates the moving speed of the target from a plurality of Doppler speed information calculated by each of the plurality of Doppler speed calculators;
A plurality of predicted hyperboloids for the next time are calculated by adding the target moving speed calculated by the moving speed calculator to each hyperboloid between the plurality of receiving devices, and a plurality of predictions for the calculated next time are calculated. An expected area setting unit for setting a logical product of hyperboloids as an expected area where a target is expected to be positioned at the next time ;
The predicted area setting unit adds a margin to a plurality of predicted hyperboloids at the next time . Receive signals transmitted from the target at a predetermined transmission frequency at multiple locations,
Based on the difference between the reception frequency of the transmission frequency and the plurality location signals received by each of the signal transmitted from the target, and calculates a plurality of Doppler velocity of the target as seen from the plurality locations respectively,
Based on the difference between the reception time of the received No. signal with the plurality of locations, respectively, to calculate the hyperbolic between said plurality of locations, positioning the target by finding the intersection of the hyperbolas between calculated in each between said plurality of locations And
Calculate the moving speed of the target from the calculated plurality of Doppler speed information,
A plurality of predicted hyperboloids at the next time are calculated in consideration of the calculated target moving speed for each hyperboloid between the plurality of locations, and a logical product of the plurality of predicted hyperboloids at the next time is calculated. Set as the expected area where the target is expected to be positioned at the next time ,
A target positioning method for adding a margin to a plurality of predicted hyperboloids at the next time .