TW201543058A - Satellite positioning-use radio wave interference detection mechanism and method, and augmentary information transmission system provided with satellite positioning-use radio wave interference detection mechanism - Google Patents

Abstract

Provided is a satellite positioning-use radio wave interference detection mechanism that can determine with a high degree of accuracy whether there is radio wave interference with a GPS signal, without increasing processing load. The satellite positioning-use radio wave interference detection mechanism comprises: a signal-to-noise ratio acquisition means that acquires a signal-to-noise ratio for a received GPS signal; a rate of change calculation means that calculates a time rate of change within a prescribed period of time with respect to the signal-to-noise ratio; and a determination means that determines whether there is radio wave interference with the received GPS signal, on the basis of the calculated time rate of change.

Description

Radio wave interference detecting mechanism for satellite positioning, radio wave interference detecting method for satellite positioning, and reinforcing information transmitting system having radio wave interference detecting mechanism for satellite positioning

The present invention relates to a system and method for determining whether a global positioning system (GPS) signal has radio wave interference.

The navigation of modern aircraft is supported by wireless facilities on the ground or by using a satellite navigation and rescue system. In recent years, the use of satellite navigation and rescue systems, because of the topography or form (land/sea) of the ground can achieve high-accuracy, high-reliability navigation on a global scale, so the development of technology and systems in advanced countries Import. Furthermore, the support for precision entry into the airport and landing for the most demanding safety of the aircraft is introduced into the Ground-Based Augmentation System (GBAS). GBAS is a system that uses GPS, GLONASS (GlObal NAvigation Satellite System) and other positioning satellites, and provides positioning and reinforcement information for aircraft for satellite navigation.

GBAS is based on the ground system to create reinforcement information, and with VHF signals, the correction information, integrity information, FAS (Final Approach Segment) via DGPS (Differential GPS) The last approach section) or the path information of the TAP (Terminal Area Path) is sent to the aircraft. The security or accuracy of navigation that cannot be obtained by GPS alone is ensured by using the reinforcement information received by the device on the aircraft.

However, the GPS signal transmitted from the GPS satellite at an output power of 50 W is affected by the medium passing through the positioning reference table, and becomes 10 to ¹⁶ W when received by the positioning reference station. Weak electric waves. Therefore, when the positioning reference table that receives the radio wave interferes with the radio wave from the other radio wave transmitting source, the waveform of the positioning signal is deformed, and the normal receiving process is hindered, and the positioning calculation cannot be performed. At this time, in GBAS, it is impossible to make high-accuracy and high-reliability reinforcement information.

Therefore, in the GBAS, it is detected whether or not there is interference of radio waves, and it is determined whether the reinforcement information made in the state of being interfered by the radio waves affects the safe navigation of the aircraft. When it is possible to create reinforcement information that hinders safe navigation due to interference of radio waves, the transmission of reinforcement information to the aircraft is stopped.

In the method of determining whether or not there is interference with radio waves or even whether the GPS signal is reliable, two methods have been generally proposed. One is the method of using the analog distance error, and the other is the method of using the carrier power to the noise power ratio.

In Japanese Laid-Open Patent Publication No. 2011-242296, it is disclosed that after correcting the influence of the ionization layer on the calculated simulation distance, a predetermined threshold value is set from the average value and the standard deviation of the correction result, and the threshold is used. A technique for determining whether a GPS satellite is faulty.

Further, in Japanese Laid-Open Patent Publication No. 2012-58185, a detection failure probability, a false alarm probability, and a lower limit in a power distribution ratio of a carrier power to a noise power ratio and a use of a carrier power to a noise power ratio have been disclosed. The technique of determining the reliability of the GPS signal by the probability of the monitoring threshold calculated by the probability.

[Previous Technical Literature] [Patent Literature]

Patent Document 1: Japanese Laid-Open Patent Publication No. 2011-242296

Patent Document 2: Japanese Patent Laid-Open Publication No. 2012-058185

When it is determined based on the analog distance output from the GPS receiver or the like and whether or not there is interference with the radio wave, the amount of calculation required for setting or determining the threshold value is large, and the load on the computer becomes a problem. Further, the error of the analog distance is not necessarily caused only by the interference of the radio waves, but also the state of the radio wave transmission process (ionosphere, convection ring) or the state of the receiver or the GPS satellite (fault), etc., and it is inferred that there are various reasons. When it is determined whether or not there is interference of radio waves using the carrier power to noise power ratio, the threshold value must be changed depending on the type of the interference wave to be detected. However, in the technique described in Patent Document 2, this is not disclosed at all. Kind of content.

The object of the present invention is to provide a radio wave interference detecting mechanism for satellite positioning, a radio wave interference detecting method for satellite positioning, and a reinforcing information transmitting system having the radio wave interference detecting mechanism for the satellite positioning, which does not increase the processing load, but can It is highly accurate to determine whether there is interference with radio waves of the GPS signal.

In order to achieve the above object, the radio wave interference detecting mechanism for satellite positioning of the present invention includes: a signal-to-noise ratio obtaining means for obtaining a signal-to-noise ratio of the received GPS signal; and a rate-of-change calculating means for calculating And the determining means is configured to determine whether there is radio interference with respect to the GPS signal received according to the calculated time change rate.

In order to achieve the above object, the enhanced information transmitting system of the present invention includes: a reinforcing information generating means for generating reinforcing information by using the received GPS signal; a radio wave interference detecting mechanism for satellite positioning; and a control means, determining that there is no In the case of radio wave interference, the above-described reinforcement information is transmitted to the mobile body, and when it is determined that there is radio interference, the generated reinforcement information is not transmitted.

In order to achieve the above object, the radio wave interference detecting method for satellite positioning of the present invention obtains a signal-to-noise ratio of the received GPS signal; and calculates a time change rate of the obtained signal-to-noise ratio within a predetermined time. And determining that there is no radio wave interference with the GPS signal when the time change rate calculated as described above is included in the predetermined range, and determining that there is a GPS when the calculated time change rate is not included in the predetermined range The radio wave interference of the signal.

According to the aspect of the invention described above, it is possible to determine whether or not there is interference with radio waves of the GPS signal without increasing the processing load.

1‧‧‧GPS satellite

2‧‧‧ Positioning reference table

3‧‧‧ Radio interference detector

3a‧‧‧ Receive signal input unit

3b‧‧‧C/No Memory

3c‧‧‧ σ memory department

3d‧‧‧Detect ^t calculation department

3e‧‧‧Thres. Input Department

3f‧‧‧C/No Judgment Department

3g‧‧‧f(σ) memory department

3h‧‧‧σ determination department

3i‧‧‧ Radio Interference Judgment Department

4‧‧‧ Strengthening Information Writer

5‧‧‧ aircraft

10‧‧‧ Strengthening Information Transmission System

20‧‧‧ Strengthening information generation means

30‧‧‧ Radio wave interference detection mechanism for satellite positioning

31‧‧‧Signal to noise ratio acquisition means

32‧‧‧Change rate calculation means

33‧‧‧ means of judgment

40‧‧‧Control means

σ ₁ ‧‧‧simulated distance error threshold

σ[m]‧‧‧simulation distance error

C/No‧‧‧Signal to noise ratio

f(σ)‧‧‧ detection probability distribution

No[W]‧‧‧Measure noise power

PRN#1 to PRN#4‧‧‧GPS satellite group

T‧‧‧ moment

Thres.‧‧‧ threshold

Fig. 1 is a view for explaining the concept of various parameters used in the reinforcement information transmitting system of the first embodiment.

Fig. 2 is a system configuration diagram of a reinforcement information transmitting system of the first embodiment.

Fig. 3 is a block diagram showing the configuration of the radio wave interference detector 3 of the first embodiment.

Fig. 4A is an example of the data stored in the C/No memory unit 3b of the first embodiment.

Fig. 4B is an example of the data stored in the σ memory unit 3c of the first embodiment.

Fig. 5 is a diagram for explaining the difference in the change of C/No and Detect due to the presence or absence of radio wave interference caused by a pulse wave.

Fig. 6 is an example of the probability distribution f(σ) of the f(σ) memory unit 3g stored in the first embodiment.

Fig. 7 is a flowchart showing the operation of the reinforcement information transmitting system of the first embodiment.

Fig. 8 is a flowchart showing the operation of the reinforcement information transmitting system of the first embodiment.

Fig. 9 is a flowchart showing the operation of the C/No determination of the reinforcement information transmitting system of the first embodiment.

Fig. 10 is a view showing an example of a permitted area when Thres. changes with time.

Fig. 11 is a view for explaining the difference in the change of C/No and Detect due to the presence or absence of radio wave interference caused by the pulse wave.

Fig. 12 is a system configuration diagram of a reinforcement information transmitting system 10 according to an embodiment of the present invention.

Fig. 13 is a block diagram showing the configuration of the radio wave interference detecting mechanism 30 for satellite positioning according to the embodiment of the present invention.

Embodiments of the invention are described. The system configuration diagram of the reinforcement information transmission system is shown in Fig. 12, and the block diagram of the radio wave interference detection mechanism for satellite positioning is shown in Fig. 13. In Fig. 12, the reinforcement information transmitting system 10 includes a reinforcement information generating means 20, a satellite positioning radio wave interference detecting means 30, and a control means 40.

The reinforcement information generating means 20 receives the GPS signals for positioning from the GPS satellites, and generates the reinforcement information using the received GPS signals. Here, the reinforcement information refers to information necessary for reinforcing the misinformation contained in the GPS signal and for calculating the precise position of the mobile body.

The satellite positioning radio wave interference detecting mechanism 30 determines whether or not there is radio wave interference with respect to the received GPS signal. In Fig. 13, the satellite positioning radio wave interference detecting mechanism 30 includes a signal-to-noise ratio obtaining means 31, a change rate calculating means 32, and a determining means 33.

The signal-to-noise ratio acquisition means 31 acquires the signal-to-noise ratio of the received GPS signal and outputs it to the noise ratio change rate calculating means 31.

The change rate calculation means 32 calculates the time change rate of the acquired signal-to-noise ratio for a predetermined time and outputs it to the determination means 33.

The determining means 33 determines whether or not there is interference with the radio wave of the GPS signal based on the time change rate of the noise ratio of the input signal. In the determination means 33 of the present embodiment, for example, when the time change rate of the signal-to-noise ratio is not included in the predetermined range, it is determined that there is radio wave interference with the GPS signal. The other side When the time change rate of the signal-to-noise ratio is included in a predetermined range, the determination means 33 determines that there is no radio wave interference with the GPS signal.

The control means 40 transmits the reinforcement information generated by the reinforcement information generating means 20 to the mobile body when the satellite positioning radio wave interference detecting means 30 determines that there is no radio wave interference. On the other hand, the control means 40 does not transmit the generated reinforcement information when it is determined that there is radio interference.

As described above, in the reinforcement information transmitting system 10, the satellite positioning radio wave interference detecting means 30 determines whether or not there is radio wave interference with the GPS signal based on the time rate of change of the noise ratio based on the signal of the received GPS signal. Thereby, the processing load is not increased, and it is possible to detect whether or not there is interference with the radio wave of the GPS signal with high accuracy.

Further, in the reinforcement information transmitting system 10, the control means 40 does not transmit the reinforcement information when it is determined that there is radio interference in the satellite positioning radio wave interference detecting means 30. Thereby, it is possible to suppress the reinforcement information with low reliability from being transmitted to the mobile body.

[First Embodiment]

[Description of composition]

The concept of various parameters used in the system of the first embodiment will be described using Fig. 1 . In this system, in order to determine whether or not there is interference from a radio wave source (not shown), the signal power C[W] and the measurement noise power No [W] of the GPS signal received in the positioning reference station 2 are used. The ratio C/No [dBHz] and the simulated distance error σ [m].

The analog distance system is defined as the time when the GPS signal transmission time between the GPS satellite 1 and the positioning reference station 2 is multiplied by the speed of light. However, due to GPS signals It is affected by the ionosphere or convection ring during its transmission, and therefore it is different from the distance measured when there is no influence such as ionosphere or convection. Further, the simulation distance also changes due to the elevation angle θ [deg.] of the GPS satellite 1 viewed from the positioning reference table 2.

The difference between the distance measured without the influence of the ionosphere or the convection coil and the actual measured distance is called the simulated distance error. Although the simulated distance error can be calculated using the actual observed data, for the sake of simplicity, the analog distance error σ and the theoretical calculation formula of the above-mentioned signal-to-noise ratio C/No are used. That is, in the case of white noise, C/No and σ satisfy the first expression.

Here, c, T _c , d, and T are respectively the speed of light [m/s], the wafer width [s], the wafer length [s], and the averaging time [s]. In the present system, it is determined whether or not C/No and the above-described σ satisfy predetermined conditions, and when predetermined conditions are satisfied, it is determined that there is no radio wave interference. Hereinafter, the determination of C/No is referred to as C/No determination, and the determination of σ is referred to as σ determination.

The reinforcing information transmitting system of this embodiment will be described. The GPS signals used in the GBAS are transmitted from the GPS satellites 1 constituting the GPS satellite group, respectively. The GPS satellite group is composed of a plurality of GPS satellites 1, and the GPS satellite 1 transmits the GPS signals for positioning to the ground while traversing the earth. In the present embodiment, four GPS satellites 1 (PRN1 to PRN4) are included. The GPS signal consists of a carrier consisting of RF sinusoidal signals, including PRN. The code of the code and the C/A code and the P(Y) code, and the navigation data including the health status of the satellite and the Ephemeris and Almanac and clock bias parameters. .

The system configuration diagram of this system is shown in Figure 2. The system includes a positioning reference group, a radio interference detector 3, and a reinforcing information generator 4.

The positioning reference station group is composed of a plurality of positioning reference bases 2 that receive GPS signals transmitted from the respective GPS satellites 1. In the present embodiment, each of the positioning reference stations 2 receives GPS signals in a period of ΔT [s]. In general, ΔT = 1 to 0.1 second. In the case of GBAS, since it is necessary to detect multipath or the like as a non-common error, the positioning reference table 2 is set to be at least 3 to 4. In the present embodiment, four positioning reference stages 2 (2-1 to 2-4) are included.

Each of the positioning reference stations 2 transmits the carrier wave, the ranging code, and the navigation data included in the received GPS signal to the reinforcing information generator 4. Further, each of the positioning reference stations 2 calculates C/No from the signal power and the noise power, and calculates σ from the calculated C/No using the first expression. Each of the positioning base stations 2 is configured to receive a GPS signal at time t, and set C/No and σ at this time to C/No ^t and σ ^{t , respectively} . Each of the positioning reference stations 2 transmits the calculated C/No ^t and σ ^t to the radio wave interference detector 3.

Fig. 3 is a block diagram showing the structure of the radio wave interference detector 3. The radio wave interference detector 3 is composed of a reception signal input unit 3a, a C/No memory unit 3b, a σ memory unit 3c, a Detect ^t calculation unit 3d, a Thres. input unit 3e, a C/No determination unit 3f, and a f(σ) memory. The unit 3g, the σ determination unit 3h, and the radio wave interference determination unit 3i are configured.

The reception signal input unit 3a receives C/No ^t and σ ^t transmitted from the respective positioning reference stations 2. Since the four positioning reference stations 2-1 to 2-4 receive the GPS signals from the four GPS satellites PRN#1 to PRN#4, respectively, the reception signal input unit 3a receives 16 C/No ^t and σ ^t .

The C/No memory unit 3b memorizes 16 C/Nos received by the reception signal input unit 3a for each reception time. As shown in FIG. 4A, C/No ^t of the GPS satellites PRN #1 to PRN #4 among the respective positioning reference stages 2-1 to 2-4 are sequentially stored in the C/No memory unit 3b.

The σ memory unit 3c memorizes the 16 σ ^t received by the reception signal input unit 3a for each reception time. As shown in FIG. 4B, σ ^t of the GPS satellites PRN #1 to PRN #4 in each of the positioning reference stations 2-1 to 2-4 is sequentially stored in the σ memory unit 3c.

Detect ^t calculating section 3d from the memory based on C C / No memory portion 3b of the / No ^t and The time change rate Detect ^t of C/No at time t is calculated. The calculation of Detect ^t is performed based on the formula (second equation) of the back-off difference shown below. In particular, Detect ^t used when detecting a pulse-shaped interference wave is expressed as PW_Detect ^t .

Thres. Input 3e accepts the threshold for C/No determination The input of Thres. Threshold Thres. is set according to the use environment of GBAS. For example, measure C/No in the state where there is no radio wave interference for about 1 year, and calculate the difference calculated by the dt interval of Equation 2 for the obtained C/No by satellite position (for example, 5° per elevation angle and azimuth angle). The cells are counted according to each observation satellite to determine the degree distribution. Furthermore, for this degree distribution, the false alarm probability value obtained from the availability requirement of the GBAS specified by the International Civil Aviation Organization (ICAO) is applied, and the obtained value is set to Limit Thres. When the take-off and landing support of the aircraft 5 is performed by the GBAS, the threshold Thres. is preferably set to be slightly smaller than the cruise time.

The C/No determination unit 3f performs C/No determination for each C/No ^t using the PW_Detect ^t calculated by the Detect ^t calculation unit 3d and the threshold Thres. received by the Thres. input unit 3e. A pulse-shaped interference wave is detected. The σ determination unit 3h of the present embodiment detects a pulse-shaped interference wave having a pulse width longer than ΔT.

The C/No decision is explained. As described above, the C/No of the GPS signal changes in accordance with the elevation angle θ when the positioning reference table 2 views the GPS satellite 1. Since θ and time t satisfy the relationship of θ=ωt, the C/No changes depending on the time t. That is, regardless of radio wave interference, C/No changes within a certain range with a change in t. Fig. 5 shows changes in C/No and Detect accompanying changes in t when the influence of radio wave interference contained in the GPS signal is removed by a broken line or when the influence of radio wave interference contained in the GPS signal is removed by a certain method. Here, it is set to ω = 0.10 rad/s. When there is no radio wave interference, the C/No and Detect systems change monotonically with the change of t.

Then consider the case of interference with radio waves. In this embodiment, It is assumed that the GPS signal interferes with the pulsed electric wave sent from the radio wave transmission source in the vicinity of t=440 s. Fig. 5 shows changes in C/No and Detect accompanying changes in t in solid lines. When there is interference with a pulsed radio wave, C/No and Detect greatly change.

In the C/No determination, it is determined whether or not the PW_Detect ^t of each measurement point indicated by the black circle shown in FIG. 5 is included in the permission area defined by the threshold Thres. Here, the threshold value is Thres.=0.5 dBHz/sec. The determination is performed for each C/No ^t , and a value of 0 or 1 is set as a flag on each signal based on the determination result. When PW_Detect is included in the license area, it is set to 0. If it is not included in the license area, it is set to 1, and then the logical sum is calculated for all C/No ^t .

The f(σ) memory unit 3g is a memory probability distribution f(σ) used for the simulation distance error σ of the σ determination. In the present embodiment, the constant period C/No is measured in a state where there is no radio wave interference or a state in which the influence of radio wave interference included in the GPS signal is removed by a certain method, and the result of the measurement according to C/No is stored. Made f(σ). Let f(σ) be shown in Fig. 6. In addition, f(σ) is standardized in such a manner as to satisfy the third formula.

When the logical sum = 1 in the C/No determination in the C/No determination unit 3f, the σ determination unit 3h performs σ determination for each σ ^t .

The σ decision is explained. In the σ determination, the simulated distance error detection failure probability reference specified by ICAO is used. The σ determination unit 3h first calculates the simulated distance error threshold σ ₁ from the detected probability distribution f(σ) and a predetermined reference value. The σ determination unit 3h of the present embodiment sets a predetermined reference value of 1 × 10 ^-5 and calculates a simulated distance error threshold σ ₁ that satisfies the fourth expression. That is, the total shaded area (hatching) portions of FIG. 6 becomes σ 1 × 10 ^-5 to is the σ _1.

The σ determination unit 3h then compares each |σ ^t | with σ ₁ to determine whether each |σ ^t | has reliability. The σ determination unit 3h determines that there is reliability when |σ ^t |<σ ₁ , and determines that there is no reliability when |σ ^t |≧σ ₁ .

The radio wave interference determining unit 3i determines whether or not the received GPS signal is reliable based on the determination result from the C/No determining unit 3f or the σ determining unit 3h, and transmits the determination result to the reinforcing information generator 4. The radio interference evaluation unit 3i indicates that the logical sum in the C/No determination is 0 or the logical sum in the C/No determination is 1, but when |σt| < σ ₁ is satisfied in the σ determination, the reinforcement information is indicated. The creator 4 transmits the reinforcement information to the aircraft 5. On the other hand, the radio wave interference determining unit 3i sets the logical sum to 1 in the C/No determination, and when the σ determination satisfies |σ ^t |≧σ ₁ , instructs the reinforcing information generator 4 not to transmit the reinforcing information to the aircraft. 5.

In the second drawing, the reinforcement information generator 4 transmits the reinforcement information signal to the aircraft 5 only when receiving an instruction to transmit the reinforcement information from the radio wave interference determination unit 3i.

The aircraft 5 receives the reinforcement information from the reinforcing information generator and the GPS signals from the GPS satellites 1 to calculate its own precise position. And height information.

[Description of the action]

Next, the operational sequence of the reinforcement information transmitting system of the present embodiment will be described using Figs. 7 and 8.

The GPS satellite groups PRN#1 to PRN#4 transmit GPS signals composed of a carrier wave, a distance code, and navigation data toward the positioning reference station groups 2-1 to 2-4 in a ΔT second period (S1).

Each of the positioning reference stations 2 receives the GPS signal from the GPS satellite groups PRN #1 to PRN #4 at time t (S2), and transmits the carrier wave, the distance code, and the navigation data to the reinforcement information generator 4. Further, each of the positioning reference stations 2 calculates a ratio C/No ^t of the power of the received signal and the power of the noise at the time of reception, and calculates a simulated distance error σ ^t (S3) according to the first equation, and calculates the calculated distance. The C/No ^t and σ ^{t are} sent to the radio wave interference detector 3.

The reinforcement information generator 4 receives the carrier wave, the distance code, and the navigation data transmitted from each of the positioning reference stations (S4), and creates reinforcement information (S5).

The radio wave interference detector 3 receives C/No ^t and σ ^t (S6) transmitted from the respective positioning reference stations 2 by the reception signal input unit 3a, and stores them in the C/No memory unit 3b and the σ memory unit 3c ( S7). The data in the C/No memory unit 3b and the σ memory unit 3c are stored as shown in Figs. 4A and 4B, respectively.

Next, the radio wave interference detector 3 acquires C/No ^t from the C/No memory unit 3b. (S8), the Detect ^t calculation unit 3d calculates the time change rate PW_Detect ^{t of the} C/No based on the second equation (S9). In order to detect an interference wave generated in a pulse shape, it is preferable that the difference interval dt is set to be small. By setting the difference interval dt to be small, it is possible to grasp the detailed time change of C/No. Therefore, even if the interference wave is generated in a pulse shape, the time change of C/No can be grasped. Here, it is set to dt=ΔT.

Next, the threshold value Thres. (>0) used in the C/No determination is acquired by the Thres. input unit 3e (S10). Even if there is no radio wave interference, C/No changes by about 2.5 dBHz from the average value C/No _∞ ^t , so the threshold Thres. is preferably about 0.5 dBHz/s. The threshold Thres. is ideally input in advance before the detection of radio wave interference is performed.

Thereafter, the C/No determination unit 3f performs C/No determination using C/No ^t and PW_Detect ^t (S11). The sequence of operations at the time of C/No determination is shown in Fig. 9. First, as shown in the fifth formula, the sizes of C/No, C/No _∞ ^t -Thres., and C/No _∞ ^t +Thres. are compared (S111).

When the fifth expression is satisfied, the flag is set to 0 (S112), and if it is not satisfied, the flag is set to 1 (S113). The C/No determination is performed for each C/No ^t , and each signal is set with a flag of 0 or 1.

After the processing of the C/No determination is performed, the logical sum of the flags set by the respective signals is calculated (S12).

Next, it is determined whether the calculated logical sum is 0 or 1 (S13). When the logical sum is 0, since the flag of all the signals is 0, it can be inferred that the radio wave interference wave is not received, and the reliability of the signal is obtained. Therefore, the instruction reinforcement information producer 4 transmits the reinforcement information to the aircraft 5. On the other hand, when the logical sum is 1, at least one of the 16 signals stored in the C/No memory unit 3b is in a state in which the flag 1 is set. Therefore, it is possible to receive radio wave interference, so the σ determination unit The σ decision is performed 3h.

When the σ determination is performed, σ ₁ satisfying the fourth expression is calculated from the detection probability distribution f(σ) stored in the f(σ) storage unit 3g and a predetermined reference value (S14). The calculated σ ₁ is transmitted to the σ determination unit 3h. Further, σ ^{t is} obtained from the σ memory unit 3c (S15).

Comparing the obtained magnitudes of σ ^t and σ ₁ (S16), when all |σ ^t | are less than σ ₁ , it is regarded as having the reliability of the GPS signal, and the instructing reinforcing information generator 4 transmits the reinforcement information. To aircraft 5. At this time, it will not be used continuously without the use of GBAS. On the other hand, among the 16 GPS signals for σ ^t determination, when there is at least one of |σ ^t | of σ ₁ or more, since the radio wave interference is received and the analog distance error detection failure probability criterion of ICAO is not satisfied, The reliability of the GPS-free signal can be inferred. Therefore, no reinforcement information is sent to the aircraft 5.

The reinforcement information generator 4 receives the reinforcement information transmission instruction after the C/No determination (S17), or receives the reinforcement information transmission instruction after the σ determination (S18), and transmits the reinforcement information to the aircraft 5 (S19).

[Explanation of effect]

The C/No determination is made before the made reinforcement information is transmitted to the aircraft 5, and the reliability of the data used for the reinforcement information is evaluated. Thereby, the reinforcement information created by suppressing the GPS signal received by the radio wave interference is transmitted to the aircraft 5, and the aircraft 5 can achieve safe navigation. Further, after the C/No determination is performed, the analog distance error detection failure probability reference defined by ICAO is referred to. Therefore, even if it is determined that there is radio wave interference based on the C/No determination, the compensation can be used as long as the analog distance error detection failure probability criterion is satisfied. Strong information, and the continuous navigation of the aircraft 5 can be carried out.

The determination based on the simulation distance error detection failure probability criterion is performed only when it is determined that there is radio interference in the C/No determination. Thereby, the time required for the determination or the calculation load can be alleviated, and the GPS signal can be quickly determined whether or not the reliability is reliable.

In the present embodiment, the threshold value Thres. is set to a constant value, but as shown in Fig. 10, the threshold value Thres. (permitted area) may be changed with time. As a result, the level of safety required for the GPS signal can be flexibly responded even if it changes at any time. For example, if the aircraft 5 performs a cruise signal, the GPS signal required for the safety of the GPS signal is low in time to set the threshold Thres. to be large, and if the time zone is high, the time zone must be high. It is desirable to set the threshold Thres. to be small.

In the present embodiment, the radio wave interference detector 3 is shown on the ground, but it may be provided on the aircraft 5.

[Second embodiment]

The second embodiment will be described with respect to a reinforcement information transmitting system for detecting whether or not there is constant radio wave interference. The time change of C/No when there is no radio wave interference or when the influence of radio wave interference is removed by a certain method is shown by a broken line in Fig. 11 . On the other hand, the time change of C/No when a constant radio wave interference is received is shown by a solid line in Fig. 11 . In the present embodiment, it is assumed that an electric wave between the t = 430 and 510 seconds and the constant time of about 40 seconds produces an interference.

[Description of composition]

When the Detect is calculated, in the first embodiment, Detect is calculated by referring to C/No before one cycle in order to detect the pulse change of C/No. In this reality In the example, Detect is calculated from C/No before a few cycles in order to detect a constant change of C/No. Here, reference is made to C/No before 5 cycles as an example.

In the present embodiment, the Detect ^t calculation unit 3d calculates Detect ^t based on the processing different from the first embodiment. The configuration other than the Detect ^t calculation unit 3d is the same as that of the first embodiment, and therefore the description thereof will be omitted.

Detect ^t 3d based retracted difference calculating portion according to the following formula (Formula 6) is calculated Detect ^t. In the present embodiment, in order to refer to C/No before 5 cycles, it is assumed that dt = 5 ΔT. In particular, Detect ^t used when detecting a constant interference wave is expressed as CW_Detect ^t .

[Description of the action]

The radio wave interference detector 3 receives C/No ^t and σ ^t (S6) transmitted from the respective positioning reference stations 2 by the reception signal input unit 3a, and stores them in the C/No memory unit 3b and the σ memory unit 3c ( S7). The data in the 4th and 4th drawings are stored in the C/No memory unit 3b and the σ memory unit 3c, respectively. Then, use C/No ^t and The Detect ^t calculation unit 3d calculates CW_Detect ^t based on the sixth equation (S9).

Next, the threshold value Thres. (>0) used in the C/No determination is acquired by the Thres. input unit 3e (S10). The C/No determination unit 3f performs C/No determination, and sets a flag of 0 or 1 for each signal (S11). After the flag is set, the logical sum of the flags is calculated for each C/No ^t (S12). When the logical sum is 0, the reinforcement information producer 4 is instructed to transmit the reinforcement information to the aircraft 5. When the logical sum is 1, the determination is made by the σ determination unit 3h (S15). As a result of the σ determination, when all of |σ ^t | are less than σ ₁ , the radio wave interference is received, but it can be inferred that the operation of the GBAS is not hindered, so the instructing reinforcement information generator 4 transmits the reinforcement information to the aircraft 5. When there is at least one of |σ ^t | of σ ₁ or more, since the safety requirements of the GBAS are not satisfied, the instructing reinforcement information generator 4 is not required to transmit the reinforcement information to the aircraft 5.

The reinforcement information generator 4 receives the reinforcement information transmission instruction after the C/No determination (S17), or receives the reinforcement information transmission instruction after the σ determination (S18), and transmits the reinforcement information to the aircraft 5 (S19).

[Explanation of effect]

By obtaining the long-term time change of C/No with reference to C/No before 5 cycles, it is possible to detect whether there is constant interference. As a result, it is possible to suppress the transmission of the reinforcement information based on the GPS signal subjected to the constant radio wave interference to the aircraft 5.

[Third embodiment]

In the first and second embodiments, Detect ^t is calculated for the purpose of detecting a single interference wave, and the threshold Thres. is set. In the present embodiment, it is assumed that there are two types of constant interference waves and pulse-shaped interference waves having different constant times. However, the constant time is set to a maximum period of n ΔT seconds.

[Description of composition]

In the present embodiment, C/No ^t is used. To calculate Detect ^t . here, Is the C/No ^t before the i cycle. In the present embodiment, based Detect ^t calculating section 3d calculates Detect ^t according to the first, the second embodiment different processes. The configuration other than the Detect ^t calculation unit 3d is the same as that of the first and second embodiments, and therefore the description thereof will be omitted.

Detect ^t calculating section 3d calculates based Detect ^t according to the following equation backward difference (Formula 7). Especially will use C/No ^t and The calculated Detect ^{t is} expressed as CW(i)_Detect ^t . However, i=1, 2 ^··· , n.

The Thres. input unit 3e receives the input of the threshold Thres. when the C/No determination unit 3f performs the C/No determination. In the present embodiment, the threshold Thres._i is set as the threshold Thres. with respect to each i.

The C/No determination unit 3f performs C/No determination for each C/No ^t using CW(i)_Detect ^t and the threshold Thres._i. In the present embodiment, C/No determination is performed for 16 × i GPS signals.

[Description of the action]

The radio wave interference detector 3 receives C/No ^t and σ ^t (S6) transmitted from the respective positioning reference stations 2 by the reception signal input unit 3a, and stores them in the C/No memory unit 3b and the σ memory unit 3c, respectively. (S7). The data of the fourth A picture and the fourth picture B are stored in the C/No memory unit 3b and the σ memory unit 3c, respectively.

Then use C/No ^t and The Detect ^t calculation unit 3d calculates CW(i)_Detect ^t (S9) from the seventh expression.

Next, the Thres._i (>0) used in the C/No determination is acquired by the Thres. input unit 3e (S10). The C/No determination unit 3f performs C/No determination, and sets a flag of 0 or 1 for each signal (S11). After the flag is set, the logical sum of the flags is calculated for each C/No ^t (S12). When the logical sum is 0, the reinforcement information producer 4 is instructed to transmit the reinforcement information to the aircraft 5. When the logical sum is 1, the determination is made by the σ determination unit 3h (S15). As a result of the σ determination, when all of |σ ^t | are less than σ ₁ , the radio wave interference is received, but it can be inferred that the operation of the GBAS is not hindered, so the instructing reinforcement information generator 4 transmits the reinforcement information to the aircraft 5. When there is at least one of |σ ^t | of σ ₁ or more, the reinforcement information generator 4 is instructed not to transmit the reinforcement information to the aircraft 5.

The reinforcement information generator 4 receives the reinforcement information transmission instruction after the C/No determination (S17), or receives the reinforcement information transmission instruction after the σ determination (S18), and transmits the reinforcement information to the aircraft 5 (S19).

[Explanation of effect]

By performing C/No determination using all C/Nos up to the i-cycle, it is possible to detect interference waves having various constant times including pulses. As a result, it is possible to suppress the reinforcement information generated based on the GPS signal subjected to the interference of the radio waves from being transmitted to the aircraft 5.

Here, the frequency of the interference wave of each constant time is first obtained when the interference of the radio wave contained in the GPS signal is removed in the absence of radio wave interference or by a certain method, and the threshold value Thres. _i is ideal. For example, when the frequency of occurrence of interference waves during a constant time of 1 second is high, but the frequency of occurrence of interference waves during a constant time of m (<n) seconds is low, it does not affect the safe operation of GBAS. By using the threshold Thres._i Set to a little smaller than the threshold Thres._m, you can detect the interference wave that affects the operation of GBAS with high probability. As a result, it is possible to suppress the transmission of the reinforcement information based on the GPS signal with low reliability to the aircraft 5.

In addition, the threshold Thres._i may also vary over time rather than being a certain value. When the intensity of the interference wave also changes with time, the threshold value Thres._i is set to match the most dominant interference wave at each time. As a result, it is possible to detect interference waves of various constant times that affect the operation of the GBAS with high probability, and to suppress the transmission of the reinforcement information with low reliability.

As an application example other than the GBAS of the present invention, for example, it is determined whether or not the reinforcement information of the GPS signal used for the automatic travel of the mobile body can be transmitted. At this time, the cruising and take-off and landing states of the aircraft correspond to parking and high-speed traveling, respectively. When the mobile body performs automatic control in a state where the highway is moving at a high speed or the like, there is a possibility that a major accident occurs due to a deviation included in the position calculated based on the GPS signal. On the other hand, since it moves at a low speed while traveling on a city street, even if the position calculated based on the GPS signal contains a slight deviation, the possibility of a major accident is low. Therefore, by changing the threshold Thres. in accordance with the moving speed of the moving body and determining the reliability of the GPS signal, it is possible to suppress the transmission of the reliability information having low reliability to the mobile body. As a result, safer automatic travel of the moving body can be performed.

The invention is not limited to the above-described embodiments, and modifications and the like within the scope of the gist of the invention are included in the invention. Further, some or all of the above embodiments may be described as the following supplementary notes, but are not limited to the following.

[Note 1]

A radio wave interference detecting system for satellite positioning, characterized in that: a method for calculating a signal-to-noise ratio of a GPS signal received at a predetermined period; and making a reinforcement information of the received GPS signal and transmitting the information to the mobile body And means for calculating a time rate of change of the signal-to-noise ratio of the received GPS signal; and means for controlling whether the reinforcing information can be transmitted to the mobile body based on the time rate of change.

[Note 2]

The radio wave interference detecting system for satellite positioning according to supplementary note 1, further comprising: a first determining means for determining whether said time change rate is included in a predetermined range; and said time change rate is not included in said predetermined range The means for creating the reinforcement information and transmitting it to the mobile body does not transmit the reinforcement information to the mobile body.

[Note 3]

The radio wave interference detecting system for satellite positioning according to supplementary note 1, further comprising: means for receiving a GPS signal at a predetermined cycle, and calculating a simulated distance error of the received GPS signal; and storing a degree distribution of the simulated distance error of the GPS signal Means; means for calculating a simulated distance error threshold from the aforementioned degree distribution and a predetermined reference value; a second determining means for comparing the magnitude of the simulated distance error with the simulated distance error threshold; and when the simulated distance error is equal to or greater than the simulated distance error threshold, determining that the received GPS signal has received a radio wave The means of handling interference.

[Note 4]

According to the radio wave interference detecting system for satellite positioning of the fourth aspect, the second determination is performed only when it is determined that the GPS signal has been subjected to radio wave interference in the first determination.

[Note 5]

The radio wave interference detecting system for satellite positioning according to Supplementary Note 1 or 2, wherein the aforementioned predetermined range refers to a range in which the influence of the pulse-like radio wave interference can be ignored.

[Note 6]

The radio wave interference detecting system for satellite positioning according to supplementary note 5, wherein the aforementioned mobile system aircraft; The aforementioned predetermined range is narrower than when the aircraft is taken off and landed.

[Note 7]

The radio wave interference detecting system for satellite positioning according to supplementary note 1, further comprising calculating the time variation according to a signal-to-noise ratio of the received signal of the GPS signal and a signal-to-noise ratio of the GPS signal received before one cycle. The means of rate.

[Note 8]

The radio wave interference detecting system for satellite positioning according to supplementary note 1, further comprising calculating the aforementioned time based on a signal-to-noise ratio of the received GPS signal and a signal-to-noise ratio of the GPS signal received before the plurality of cycles Means of rate of change.

[Note 9]

The radio wave interference detecting system for satellite positioning according to supplementary note 1, further comprising: a signal-to-noise ratio according to a signal of the received GPS signal, and a signal-to-noise ratio of each GPS signal received up to a plurality of cycles The means for calculating the aforementioned time change rate are respectively calculated.

[Note 10]

A radio wave interference detecting method for satellite positioning, comprising: calculating a signal-to-noise ratio of a GPS signal received at a predetermined period; and calculating a noise ratio using a signal of the received GPS signal a step of determining a time rate of change of a signal of the received GPS signal to a noise ratio; performing a first determination of whether the time rate of change is included in a predetermined range; and the time rate of change is not included in the predetermined range In the meantime, the step of stopping the transmission of the reinforcement information is performed for the means for generating the reinforcement information of the received GPS signal and for transmitting to the mobile body.

[Industrial availability]

The invention of the present invention can be widely applied to a GBAS that uses a GPS signal to calculate position information, an automatic travel system of a mobile body, and the like.

This application claims Japan to be applied for on February 27, 2014. Priority is claimed on Japanese Patent Application No. 2014-036092, the entire disclosure of which is hereby incorporated by reference.

1‧‧‧GPS satellite

2‧‧‧ Positioning reference table

Claims (10)

A radio wave interference detecting mechanism for satellite positioning includes: a signal-to-noise ratio obtaining means for obtaining a signal-to-noise ratio of a received GPS signal; and a rate-of-change calculating means for calculating the obtained signal pairing And a determining means for determining whether there is interference with the radio wave received by the GPS signal received according to the calculated time rate of change. The radio wave interference detecting mechanism for satellite positioning according to the first aspect of the invention, wherein the predetermined time period is shorter than a pulse width of the pulsed electric wave. The radio wave interference detecting mechanism for satellite positioning according to the first aspect of the invention, wherein the predetermined time period is a length of a radio wave in which a standing wave that interferes with the GPS signal is detected. The radio wave interference detecting mechanism for satellite positioning according to any one of claims 1 to 3, wherein the determining means determines that there is no GPS signal when the calculated time change rate is included in a predetermined range. The radio wave interferes, and when the calculated time change rate is not included in the predetermined range, it is determined that there is radio wave interference with the GPS signal. A reinforcing information transmitting system, comprising: a reinforcing information generating means for generating reinforcing information by using the received GPS signal; and applying for a radio wave interference detecting mechanism for satellite positioning according to item 4 of the patent scope; When it is determined that there is no radio wave interference, the control means transmits the generated reinforcement information to the mobile body, and when it is determined that there is radio interference, the generated reinforcement information is not transmitted. A reinforcement information transmission system according to claim 5, further comprising a simulation distance error calculation means for calculating a simulation distance error σ using the received GPS signal; wherein the control means determines that there is radio interference Further, it is determined whether or not the aforementioned simulated distance error σ satisfies the analog distance error detection failure probability criterion, and when satisfied, the generated reinforcement information is transmitted to the mobile body. A reinforcing information transmitting system according to claim 6 of the patent application, further comprising a σ threshold calculating means for calculating a simulated distance based on a degree distribution of a simulated distance error σ of the GPS signal without radio interference and a predetermined reference value The error threshold σ'; the control means determines that the simulation distance error detection failure probability criterion is satisfied when |σ|<σ', and determines that the simulation distance error detection is not satisfied when |σ|≧σ' A failure probability benchmark. A reinforcing information transmitting system according to claim 5, wherein the aforementioned mobile system aircraft; the predetermined range applicable to the determining means when the aircraft is taken off and landed is set to be used when the aircraft is cruised. The aforementioned predetermined range is narrower. A reinforcing information transmitting system according to item 5 of the patent application scope, further comprising receiving means for receiving the aforementioned GPS signal. A radio wave interference detecting method for satellite positioning is to obtain a signal-to-noise ratio of a received GPS signal; and calculate a time change rate of the obtained signal-to-noise ratio within a predetermined time; and When the time change rate is included in the predetermined range, it is determined that there is no radio wave interference with respect to the GPS signal, and when the calculated time change rate is not included in the predetermined range, it is determined that there is radio wave interference with the GPS signal.