JP3354668B2 - Jammer detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a jammer detecting apparatus for detecting and identifying the position of a jammer transmitting a jammer to a radio station performing spread spectrum (hereinafter referred to as "SS") communication. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a jamming radio detection device that achieves high-accuracy position identification using pilot radio waves spread in a sequence.

[0002]

2. Description of the Related Art As a conventional technique for detecting and identifying the position of an interfering station transmitting an interfering radio wave to a radio station performing SS communication, the correlation delay amount of a received wave using three or more monitor stations is known. There is a multi-monitor system that specifies the position of the source of the jamming radio wave from the Internet. Hereinafter, this method will be described with reference to FIG.

In the figure, the jamming radio wave transmitted from the jamming station 1 is divided into first, second, third and fourth monitoring stations 2a to 2a.
d. Then, the interfering radio waves received by the monitor stations 2a to 2d are transmitted to the processing station 4 via the electric communication paths 3a to 3d formed by coaxial cables and the like, respectively. The processing station 4 specifies the position of the jamming station 1 based on the jamming radio waves transmitted from the monitor stations 2a to 2d. It is assumed that the monitor stations 2a to 2d are located at points r ₁ to r ₄ meters from the antenna end of the jamming station 1, respectively. Further, since the position of the interfering station can be specified if there are at least three monitor stations, the case of three monitor stations will be described below as an example. The principle of specifying the position of the jamming station will be described in detail. The jamming station 1 sends the following jamming radio wave X (t) from its own antenna.

[0004]

(Equation 1)

Note that j = √-1, t is time, f _C is the carrier frequency of the jamming radio wave, and a (t) is the complex envelope of the jamming radio wave. The above a (t) is a complex number having the following characteristics. That is, a (t) is a complex stochastic process and a stationary process. The expected value of a (t) is 0,
If the autocorrelation function of a (t) is R _a (τ), and the power spectral density of a (t) is S _a (f), the Wiener-Hinchin theorem of the following equation holds.

[0006]

(Equation 2)

Further, a (t) is band-limited,
The assumption that S _a (f) = 0, | f |> B / 2> 0 (where B is the bandwidth (full width) of the jamming radio wave X (t) and B << f _C ) is continuous. Carrier a (t) = 1 or continuous tone a (t)
If it is other than = a ₀ cos (2πf _B t), it holds for almost all jamming radio waves. When the jamming radio wave X (t) having the above characteristics is transmitted from the antenna of the jamming station 1 and reaches a point r ₀ meters away from the antenna end, one of the electromagnetic field components of the jamming radio wave becomes It looks like an expression.

[0008]

(Equation 3)

Here, C ₀ is a complex propagation loss, and τ ₀ is a propagation delay time, which is represented by τ ₀ = r ₀ / c (c is the speed of light). Based on the above equation (3), the jamming radio wave received by the first monitor station 2a (r ₁ meter away from the jamming station 1) and sent to the beginning of the electric communication path 3a is expressed by the following equation. You.

[0010]

(Equation 4)

C ₁ ′ is a loss from the antenna end of the jamming station 1 to the beginning of the electric communication path 3 a, and τ ₁ ′ is a delay time from the antenna end of the jamming station 1 to the beginning of the electric communication path 3 a. τ ₁ ′ is represented by τ ₁ ′ = r ₁ / c + τ _M1 , in which case,
τ _M1 is the intra-station delay time of the first monitor station 2a. Then, the jamming radio wave represented by the above equation (4) is transmitted to the electric communication path 3a.
, And is received by the processing station 4 as follows.

[0012]

(Equation 5)

C ₁ is the total loss from the antenna end of the jamming station 1 to the processing station 4 via the first monitor station 2 a and the electric communication path 3 a, and τ ₁ is the _first loss from the antenna end of the jamming station 1. The total delay time from the monitor station 2a to the processing station 4 via the electric communication path 3a. τ ₁ is expressed by the following equation, in which case τ 1
_B1 is a delay time of the electric communication path 3a. τ ₁ = r ₁ / c + τ _M1 + τ _B1 (6) On the other hand, the interfering radio waves received by the second monitor station 2b and the third monitor station 2c are also the first monitor station 2a described so far. Are transmitted to the processing station 4 via the electric communication paths 3b and 3c, respectively, in the same manner as in the case where the data is received. And
The interfering radio waves received by the processing station 4 from the second monitor station 2b and the third monitor station 2c are expressed by the following equation (7), respectively.
It is expressed by equation (8).

[0014]

(Equation 6)

Note that C ₂ and C ₃ are total losses corresponding to the above-described C ₁ , and τ ₂ and τ ₃ are total delay times corresponding to the above-mentioned τ ₁ . τ ₂ and τ ₃ are respectively τ ₂ = r ₂ / c + τ _M2
+ Τ _B2 , τ ₃ = r ₃ / c + τ _M3 + τ _B3 , where τ _M2 and τ _M3 are the second monitor station 2b and the third monitor station, respectively.
Τ _B2 and τ _B3 are the delay times of the electric communication path 3b and the electric communication path 3c, respectively. After receiving the jamming radio waves transmitted from the monitor stations 2a to 2c, the processing station 4 converts the intermediate frequency at which the position of the jamming station 1 can be easily processed, that is, the following equation (9). In the expression (9), i is i = 1, 2, 3. Specifically, the jamming waves represented by the above equations (5), (7) and (8) are calculated based on the equation (9) as shown in the following equations (10), (11) and (12). Is converted.

[0016]

(Equation 7)

Note that f _I is an intermediate frequency obtained by converting the carrier frequency (f _C ), and A _i (A ₁ , A ₂ and A ₃ ) is the interference station 1
Is the total loss (complex number) from the antenna end to the processing station 4 via the respective monitor stations 2a to 2c until it is converted to an intermediate frequency. Next, the processing station 4 performs the above (10), (11)
Using equations (12) and (12), the cross-correlations R ₁₂ and R ₁₃ for the next T seconds starting at time t ₀ and completing at t ₀ + T are calculated. Note that R ₁₂ and R ₁₃ are represented by the following equations (13) and (14), and in this case, T is T >> τ ₁ + τ ₂ + τ ₃ .

[0018]

(Equation 8)

The calculation results of the above two equations are respectively as follows:
Expressions (15) and (16) are obtained.

[0020]

(Equation 9)

At this time, the aforementioned τ ₁ (= r ₁ / c + τ _M1 +
τ _B1 ), τ ₂ (= r ₂ / c + τ _M2 + τ _B2 ) and τ ₃ (= r ₃ / c
+ Τ _M3 + τ _B3 ) is always constant irrespective of the time, and the absolute values of the cross-correlations R ₁₂ and R ₁₃ are given by the following (17) and (1)
Equation 8) is obtained. Then, the cross-correlation from time t ₀ to t ₀ + T becomes independent of t ₀ .

[0022]

(Equation 10)

In equations (17) and (18), | R
_Since the maximum value of _a (τ) | is when τ = 0, the maximum values of X ₁₂ (τ) and X ₁₃ (τ) are τ = τ ₂ −τ ₁ and τ =
Given when τ ₃ −τ ₁ . Further, the above-mentioned τ ₁ = r ₁ /
c + τ _M1 + τ _B1 , τ ₂ = r ₂ / c + τ _M2 + τ _B2 and τ ₃ = r
_By subtracting τ ₂ −τ ₁ and τ ₃ −τ ₁ using ₃ / c + τ _M3 + τ _B3 , the following equations (19) and (20) are derived.

[0024]

[Equation 11]

In these two equations, each of the monitor stations 2a to 2a
2c intra-station delay time τ _M1 , τ _M2 , τ _M3 and each electric communication path 3
If the delay times τ _B1 , τ _B2 , τ _{B3 of a} to 3c are known in advance by different measurements or the like, the result of the cross-correlation (τ =
τ ₂ −τ ₁ and τ = τ ₃ −τ ₁ ) and the speed of light (c),
r ₂ −r ₁ and r ₃ −r ₁ can be calculated. Therefore, the relative distance between the two monitoring stations and the jamming station, r ₂ −
From r ₁ , r ₃ -r ₁ , the antenna position of the interfering station can be specified from the plane coordinates of the monitor station by the same principle as in the hyperbolic navigation.

[0026]

The prior art described above has the following problems. Intra-station delay time τ _M1 , τ _M2 , τ of each monitor station 2a to 2c
Delay time τ _B1 , τ _B2 , τ of _M3 and each of the electric communication paths 3a to 3c
_B3 has to be measured in advance. Since the environmental conditions such as temperature, humidity, and vibration are different between when the delay time is measured in advance and when the position of the interfering station is actually detected and specified, the position cannot be specified accurately. The details of this problem will be described below. In particular, the delay time of a telecommunication path varies greatly with the temperature of the atmosphere in which it is located. For example, when a 1.3 μm zero-dispersion optical fiber whose delay time is stable is used as an electric communication path, if the temperature changes by 1 ° C., 1 km per 1 km of the optical fiber.
The delay time of about 00p seconds changes. Therefore, in the case of a large-scale detection of an interfering station in which an optical fiber is laid for 20 km, if the temperature fluctuation is 10 ° C., the fluctuation of the delay time reaches 20 ns, which is an amount corresponding to an error of 6 m. It is not negligible for the purpose of detecting. SUMMARY OF THE INVENTION It is an object of the present invention to provide an interference radio wave detection device which solves the above-mentioned problems and improves the accuracy of specifying the position of an interference station.

[0027]

The SS communication has a low power density and can effectively use the entire spectrum.
Being spotlighted by mobile radio. Interference with SS communication is often performed, and it is necessary to specify the location of the source of the jamming radio wave. In a conventional modulation method, for example, communication of FM, AM, etc., it is sufficient to detect the transmission source of the carrier. However, in SS communication, since the power density is low, some contrivance is required. The present invention focuses on the fact that the interfering wave for SS communication does not match the designation of the spreading code and has large energy, and utilizes three or more monitor stations to determine the source of the interfering wave from the correlation delay amount of the received wave. A multi-monitor method for specifying a position is used. In this multiple monitor system, it is said that the position identification accuracy can be improved by increasing the number of monitor stations. However, in practice, the correlation is reduced due to fluctuations in the delay amount of an electric communication path formed by a cable or the like. It was difficult to obtain a peak.

Therefore, according to the present invention, a pilot station that generates a pilot wave which is spread spectrum by a designated code and has no information is placed as a fixed station, and a monitor station receives the pilot wave and the jamming wave at the same time.
The signal is transmitted to the processing station via a telecommunication path isolated from jamming radio waves, and the processing station extracts pilot radio waves from those radio waves and performs despreading processing, and performs telecommunications based on information obtained from the result of the despreading processing. Estimates the delay time in the channel and the monitor station, corrects the delay time, calculates the cross-correlation between the signals received by any two of the monitor stations, and calculates the propagation delay of the jamming radio wave reaching the two stations. The time difference was measured to locate the jamming station.

[0029]

[Action] Pilot station is a fixed station, known in certain types of pseudo-noise sequence _{(···· P -3, P -2,} P -1, P 0, P 1,
, P ₂ , P ₃ ,...), The pilot radio wave having the spectrum spread by the direct spreading method is always transmitted. The pseudo noise sequence P _k has a period N and is represented by the following equation. P _k = P _{k + N} (21) k is an arbitrary integer, and N is an integer of 2 or more. actually,
N is set to be sufficiently large, for example, 2 ²³ -1.
Further, the pseudo noise sequence P _k is also represented by the following equation.

[0030]

(Equation 12)

Note that M is a finite set, and the elements are complex numbers. Actually, M has BPSK (Binary-phase-shift).
keying) M = {-1,1} used for modulation and Q
M used for PSK (Quadriphase-shift keying) modulation
= {1, -1, j, -j}. The pilot radio wave is directly spread with such a pseudo noise sequence. Then, one of the electromagnetic field components of the pilot radio wave transmitted from the antenna of the pilot station is represented by the following equation.

[0032]

(Equation 13)

Note that f _P is the carrier frequency of the pilot radio wave, h (t) is the impulse response of the baseband filter (shown by the following equation (24)), and T _C is the symbol period of the spreading code.

[0034]

[Equation 14]

On the other hand, the monitor station receives the pilot radio wave and the jamming radio wave at the same time and sends them out to the electric communication path. Also,
The processing station receives both radio waves from the electric communication path, measures the delay time from the antenna end of the pilot station to the monitor station and the electric communication path by despreading the pilot radio wave, and also measures the delay time between the two monitor stations. Is performed.

Here, the principle used in the present invention will be analyzed more strictly. In FIG. 1, the pilot station 5
Pilot wave V _P (t) transmitted from the antenna end of
Reaches the antenna end of the first monitor station 6a at a distance of r ₁ ′ meters from the antenna end of the pilot station 5 with a delay time of τ _P1 , and furthermore, the delay time τ _M1 in the first monitor station 6a and the The signal reaches the processing station 7 under the influence of the delay time τ _B1 of the communication path 3a. Each monitor station 6a in FIG.
The distances (r _{1 to} r ₄ ) from the interfering station 1 to 6 d and the intra-station delay times (τ _{M1 to} τ _M4 ) are shown in FIG.
２2d. The pilot radio wave received from the first monitor station 6a by the processing station 7 is represented by the following equation.

[0037]

(Equation 15)

Τ ₁ ′ is the total delay time from the antenna end of the pilot station 5 to the processing station 4 via the first monitor station 6a and the electric communication path 3a, and is expressed by the following equation. despread _{τ 1 '= r 1' /} c + τ M1 + τ B1 ···· (26) (r 1 'V 1 / c = τ P1, c is the speed of light) represented by the above equation (25)' ( By performing the processing, the total delay time τ ₁ ′ can be known, or a time system t−τ ₁ ′ synchronized with the pilot radio wave can be created.

Next, the fact that the position of the interfering station 1 can be specified by spreading and demodulating the pilot radio wave will be described. That is,
Since the pilot station 5 is a fixed station, τ _P1 = r ₁ '/ c
Is known as a constant value. Therefore, even when τ _M1 and τ _B1 fluctuate due to environmental changes or the like, τ ₁ (formula (6))
And τ ₁ ′ (formula (26)) (see formula (27) below), the distance r ₁ from the antenna of the interfering station 1 to the first monitor station 2a can be known. τ ₁ −τ ₁ ′ = r ₁ / c r ₁ ′ / c (27) Specifically, the relationship of the following equation (28) is applied to the above equation (9), Cross-correlation is performed on Z _i (complex number). Here, T ₀ is a fixed number and T ₀ −τ ₁ ′> 0.

[0040]

(Equation 16)

That is, as shown in the following equations (29) and (30), the intra-station delay time τ of the i-th monitoring station 2a to 2c is obtained.
_Mi is independent of the delay time τ _Bi of each of the electric communication paths 3a to 3c.

[0042]

[Equation 17]

Accordingly, since T ₀ and r _i ′ in the above equation (30) are known, the maximum value of the cross-correlation is obtained.
_i (ie, r ₁ , r ₂ , r ₃ ) is known. by this,
The position of the source of the jamming radio wave can be specified by the same principle as that of the hyperbolic navigation.

[0044]

FIG. 1 is a schematic block diagram of a jammer detecting apparatus according to an embodiment of the present invention. The jamming station 1 transmits jamming radio waves to radio stations that are performing SS communication. Also,
A pilot station 5, which is a fixed station, transmits a pilot radio wave that has been spread with a pseudo noise sequence in order to specify the position of the interfering station 1. The first, second, third, and fourth monitor stations 6a to 6d receive the above-mentioned jamming radio waves and pilot radio waves, convert them into a signal format suitable for transmission, and then form a telecommunications system such as a coaxial cable. Roads 3a-3d
To send to. The processing station 7 receives the jamming radio waves and the pilot radio waves from the monitor stations 6a to 6d sent via the electric communication paths 3a to 3d, and processes them to specify the position of the jamming station 1. . The monitor station 6a
6d are located at points where the distance from the antenna end of the jamming station 1 is r ₁ to r ₄ meters and the distances from the antenna end of the pilot station 5 are r ₁ ′ to r ₄ ′ meters, respectively. Shall be located at

(First Embodiment) The details of each configuration will be described below with reference to FIGS. As shown in FIG. 2, the pilot station 5 (fixed station) is a double superheterodyne transmitter, and always generates a pilot wave that is spread spectrum by BPSK modulation using a 23-stage M-sequence pseudo-noise sequence. Let me send. Specifically, it is a pseudo-noise sequence represented by N = 2 ²³ −1 and M = {− 1, 1} in the equations (21) and (22) described in the section of operation. Further, in equation (23), the pilot wave carrier frequency f _P = 2484MH _Z, the impulse response h of the baseband filter (t) = sinc (t / T C),
This is a pilot radio wave having an electromagnetic field component represented by the symbol period T _C of the spreading code = 100 nsec.

Such pilot radio waves are generated as follows. That is, the clock oscillator 51 generates a clock accurate 10 MHz _Z. The 23-stage M-sequence generation circuit 52 generates an M-sequence pseudo-noise sequence signal of N = 2 ²³ -1 cycle based on the clock from the clock oscillator 51. Frequency synthesizer 53a, 53b, based on the clock from the clock oscillator 51, respectively, the 2LO signal 484MH _Z, first 2000MH _Z
LO signal is being generated. Double balanced mixer 54a
Is a pseudo-noise sequence signal output from the 23-stage M-sequence generation circuit 52 and 4 pseudo-noise sequence signals output from the frequency synthesizer 53a.
Outputs a BPSK signal 484MH _Z by mixing the first 2LO signal 84MH _Z. The band-pass filter 55a is
The BPSK signal is output after removing unnecessary waves.

The double-balanced mixer 54b outputs the 484 MHz _Z B output from the band-pass filter 55a.
By mixing the first 1LO signal outputted 2000MH _Z from the PSK signal and the frequency synthesizer 53b, 1516
And it outputs the BPSK signal of MH _Z and 2484MH _Z. The band-pass filter 55b converts these BPSK signals into 2
484MH _Z by selecting only BPSK signal and outputs to the power amplifier 56. BPSK signal of the 2484MH _Z, after being amplified to a predetermined output by the power amplifier 56, and transmitted from the antenna 58 via the feed line 57. The frequency stability of the clock may be about 10 ⁻¹¹ or less per second, which can be realized by a highly stable crystal oscillator. In this case, the frequency variation in the 2.4 GHz _Z ^{bands, 2.4 × 10 9 × 10 -11} × √ ( elapsed time) H _Z R
Become MS.

On the other hand, the monitor stations 6a to 6d are dual superheterodyne receivers as shown in FIG. A pilot radio wave (BPSK signal) of _Z is received, converted into a signal format suitable for transmission, and then transmitted to the electric communication paths 3a to 3d. That is, the jamming radio wave and the pilot radio wave (hereinafter, referred to as a reception signal) received by the antenna 61 are input to the band-pass filter 63a via the power supply line 62. Bandpass filter 63a, for example 2484MH _Z has a band of ± 10 MHz _Z, and outputs except the unnecessary waves other than the band from the received signal to the low noise amplifier 64. The clock oscillator 65 is to generate a clock for accurate 10 MHz _Z.
Each of the frequency synthesizers 66a and 66b has a frequency of 2000M based on the clock from the clock oscillator 65.
The 1LO signal H _Z, is generating a first 2LO signal 470MH _Z.

The 2484 MHz _Z- band signal amplified and output by the low noise amplifier 64 is output from the frequency synthesizer 66 a by the double balanced mixer 67 a.
After being mixed with the 1LO signal 000MH _Z, is band-limited by band-pass filter 63 b, is converted to a 1IF signal 484MH _Z band (± 10MH _Z). The first IF signal is further supplied to a double balanced mixer 6.
7b, 47 output from the frequency synthesizer 66b
After being mixed with the 2LO signal 0MH _Z, it is band-limited by band-pass filter 63c, 14MH _Z band (± 10
MH _Z ). Electro-optical converter 6
8 (comprising a laser diode or the like)
After receiving the signal and converting it into light intensity, the signal is output to an electric communication path composed of an optical fiber, for example, the electric communication path 3a in the case of the first monitor station 6a. The frequency stability of the clock may be about 10 ^-11 or less per second as in the case of the pilot station 5, which can be realized by a highly stable crystal oscillator.

The processing station 7 is configured as shown in FIG. 4, and combines the jamming radio waves and the pilot radio waves transmitted from the monitor stations 6a to 6d via the electric communication paths 3a to 3d. The position of the jamming station 1 is specified by receiving the signals and processing them. That is, the second IF transmitted from the first monitor station 6a via the optical fiber
An optical signal having a signal (combined signal of the jamming radio wave and the pilot radio wave) as a component is input to the photoelectric converter 100a, and the signal is again input to the photoelectric converter 100a.
It is converted into an electric signal of 4 mH _Z band (± 10MH _Z). This 14 MHz _Z band signal is supplied to a despreading circuit 101 and a quadrature detector 102.
Is input to Despreading circuit 101 takes out only the pilot wave from the 14MH _Z band signals, and despreading processing of the pilot wave, the recovered carrier (14M
H _Z), and extracts the symbol clock (10 MHz _Z) and Epoch ^{_{(10MH Z ÷ (2 23 -1}} )). The epoch is a pulse indicating the beginning of the pseudo noise sequence, and its period is T _C (symbol period) × N (2 ²³ −1).

The quadrature detector 102 is a 90-degree hybrid 103
And a double-balanced mixer 104a, 104b,
The reproduced carrier wave output from the despreading circuit 101 is orthogonally distributed by the 90-degree hybrid 103, and the orthogonally distributed reproduced carrier wave is output from the photoelectric converter 100a.
The divided 14 MHz _Z band signals are mixed by double-balanced mixers 104a and 104b, respectively, to output baseband signals of I and Q components. I, the baseband signal Q component, respectively, the low-pass filter 105a of the cut-off frequency 10 MHz _Z, unwanted waves are removed by 105b A /
It is output to D converters 106a and 106b.

[0052] The timing circuit 107, based on the input from the despreading circuit 101 symbol clock (10 MHz _Z) and Epoch ^{_{(10MH Z ÷ (2 23 -1}} )), the sampling pulse (30 mH _Z) and sample number Generate and output K. Note that the sample number K is set to 0 at the rising or falling edge of the epoch, and K = 0, 1, 2, 3,..., {3 × (2 ²³ −1) −1}. The number of ranges is monotonically increasing one by one in synchronization with the sampling pulse, and the sampling pulse is an A / D converter.
This serves as a conversion start signal for 106a and 106b. The A / D converters 106a and 106b are low-pass filters 105a and 105, respectively.
The baseband signals of the I and Q components output from 5b are A / D converted (for example, quantized with a 12-bit resolution) in synchronization with the sampling pulse and output. The photoelectric converter 100a, the despreading circuit 101, the quadrature detector 102, the low-pass filters 105a and 105b, the A / D converters 106a and 106b, and the timing circuit 107 constitute a baseband signal generation circuit 71a. ing.

The baseband signal generation circuit 7 as described above
Baseband signal generation circuit 71 having the same function as 1a
b to 71d are also provided corresponding to the electric communication paths 3b to 3c, respectively, and the second, third and fourth monitor stations 6b are respectively provided.
Based on the combined signal of the interfering radio wave and the pilot radio wave transmitted from .about.6d, the baseband signals I _K and Q _{K of} the quantized I and Q components and the sample number K are generated. The cross-correlation calculator 72 is composed of a memory, a multiplier and an accumulator.
Receiving the quantized baseband signals I _K and Q _{K of} the I and Q components and the sample number K, respectively, inputted from 〜71d, and performing a discrete cross-correlation operation, the above-mentioned (17) and (18)
X ₁₂ (τ) and X ₁₃ (τ) shown in the equation and X ₁₄ (τ) derived in the same manner are output. The position measuring device 73 is
Based on these X ₁₂ (τ), X ₁₃ (τ) and X ₁₄ (τ), τ that gives the maximum value is calculated, and the position of the jamming station 1 is specified.

(Second Embodiment) This embodiment is different from the first embodiment in that the configurations of the monitor stations 6a to 6d and the processing station 7 are changed. Therefore, the schematic configuration of the jammer detection device is as shown in FIG. 1, and the pilot station 5 is as shown in FIG. The configurations of the monitor stations 6a to 6d and the processing station 7 in the second embodiment are shown in FIGS. 5 and 6, respectively. In addition,
The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted.

Referring to FIG. 5, each monitor station 6a to 6d will be described. Pilot radio jamming and 2484MH _Z (BPSK signal) as in the first embodiment, 484MH _Z zone after being received by the antenna 61 (± 10M
H _Z ) is converted into a first IF signal, and the band-pass filter 6
3b. This 484 MHz _Z band signal is input to the despreading circuit 201 and the quadrature detector 202. Despreading circuit 20
1, takes out only the pilot wave from the 484MH _Z band signal, as in the first embodiment, and despreading processing of the pilot wave, the recovered carrier (48
4 mH _Z), and extracts the symbol clock (10 MHz _Z) and Epoch ^{_{(10MH Z ÷ (2 23 -1}} )).

[0056] quadrature detector 202 of the 484MH _Z band by mixing the 484MH _Z band signal 2 min is output from the reproduction carrier and band-pass filter 63b outputted from the despreading circuit 201, I, Q Output the baseband signal of the component. The I, Q baseband signals components, respectively, the low-pass filter 105a of the cut-off frequency 10MH _Z, A / D converter 106a after unnecessary waves are removed by 105b, are input to 106b, the timing circuit 107 A / D conversion is performed in synchronization with the output sampling pulse.
The multiplexing circuit 205 multiplexes the quantized baseband signals I _K and Q _{K of} the I and Q components and the sample number K and outputs the result to the electro-optical converter 68. The electro-optical converter 68 (comprising a laser diode or the like) receives these signals and converts them into optical ON / OFF signals, and converts them into an electric communication path composed of an optical fiber, for example, the first monitor station 6a. In the case of, the signal is output to the electric communication path 3a.

Next, the processing station 7 will be described with reference to FIG. From the first monitor station 6a to the optical fiber (the electric communication path 3)
The optical signal transmitted via a) is converted into an optical-electrical
The signal is input to 0a and converted into an electric signal again. That is, the quantized I and Q component baseband signals I _K ,
An electric signal obtained by multiplexing Q _K and the sample number K is output. The demultiplexing circuit 206a receives the multiplexed electric signal from the photoelectric converter 100a and quantizes the I and Q signals.
The component baseband signals I _K and Q _K and the sample number K are separated and output to the cross-correlation calculator 72. As described above, the optical signals transmitted from the second, third, and fourth monitoring stations 6b to 6d via the optical fibers (the electric communication paths 3b to 3d) are also used as described above. Demultiplexing circuit 206b
After being converted into electric signals by ~ 206d,
The quantized baseband signals I _K and Q _{K of} the I and Q components and the sample number K are separated. Then, similarly to the first embodiment, a discrete cross-correlation calculation is performed by the cross-correlation calculator 72, and the position of the interfering station 1 is specified by the position measurement device 73.

(Other Embodiments) In the first and second embodiments, the case where the optical communication lines 3a to 3d use optical fibers has been described. However, the present invention is not limited to this. It may be a wireless transmission line that is not easily affected (for example, a 2GHz _Z microwave line of the FM system).

[0059]

According to the present invention, the interference wave is received simultaneously with the pilot wave, the time information contained in the pilot wave is extracted by despreading, and the cross-correlation of the interference wave is obtained between different monitor stations based on this. Therefore, the position of the interfering station can be specified with high accuracy without being affected by the delay time of the electric communication path or the delay time in the monitor station.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a jammer detection device showing an embodiment of the present invention;

FIG. 2 is a diagram showing a configuration of a pilot station;

FIG. 3 is a configuration diagram showing a first embodiment of a monitor station;

FIG. 4 is a configuration diagram showing a first embodiment of a processing station,

FIG. 5 is a configuration diagram showing a second embodiment of the monitor station;

FIG. 6 is a configuration diagram showing a second embodiment of the processing station;

FIG. 7 is a schematic configuration diagram of a conventional jammer detection device.

[Explanation of symbols]

1... Jamming station, 2a to 2d, 6a to 6d... Monitor station,
3a to 3d: electric communication path, 4, 7, processing station, 5:
Pilot station.

Claims (1)

(57) [Claims] 1. A fixed transmission for transmitting a pilot radio wave having a spectrum spread using a predetermined pseudo-noise sequence.
And position placed pilot station (5), and said pilot radio a function of the jamming can be received simultaneously, the received radio waves can be delivered into a signal format suitable for transmission function and each comprising a different was put in place three stations or more monitors station (6 a to 6 d), said isolated from jammer, telecommunications path kicked set <br/> in response to said monitor station (3 a to 3 d), signals, each sent out of the monitor station receives through the telecommunication channel, and despreading processing extracts a pilot wave from each of the signal received, based on the results obtained information from the inverse diffusion processing A function of estimating the delay time in the electric communication path and the monitor station, and performing a cross-correlation operation between signals received by any two of the monitor stations while correcting the estimated delay time, Reach the two stations And a processing station (7) having a function of measuring the difference in propagation delay time of the interfering radio waves.