CN1053304C - Frequency-hopping signal direction finding and intercept receiving method based on first-order bandpass sampling - Google Patents
Frequency-hopping signal direction finding and intercept receiving method based on first-order bandpass sampling Download PDFInfo
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Abstract
The present invention discloses a direction-finding, detecting and receiving method for a frequency hopping signal on the basis of first-order band-pass sampling. According to the characteristic that the interval between the frequency points of the frequency hopping signals is an integral multiple of a channel interval, the signals on all the frequency points can be moved to the same low frequency by the first-order band-pass sampling, and then the directions of multiple signals are found by an array direction-finding method so as to detect and receive the signals by digital beam forming; a broadband filter at a low frequency and a medium frequency and a beam forming algorithm are added to only conventional array direction-finding equipment so as to realize an integral direction-finding, detecting and receiving system for a frequency hopping signal. Therefore, the present invention has the characteristics of simple equipment, favorable performance, easy use, low cost, popularization value, application value, etc.
Description
The present invention relates to the direction finding and the intercept receiving method of a kind of Frequency Hopping Signal in the signal reconnaissance field, be specially adapted to the direction-finding system based on the array df method is expanded to the Frequency Hopping Signal direction finding and detects the incorporate system of receiving.
Frequency hopping communications is a kind of comparatively ripe spread spectrum communication technology at present, obtained using widely in multiple field owing to have stronger anti-intercepting and capturing and interference free performance, especially in the military communication field, Frequency Hopping Signal generally is to utilize pseudo noise code to change the carrier frequency frequency of signal, make it saltus step on the frequency set that is spaced apart standard channel interval integral multiple between the intrinsic Frequency point, at receiving terminal in order to receive Frequency Hopping Signal, need be synchronous with transmitting terminal, this just need know the key of frequency hopping pattern.The intercepting and capturing of Frequency Hopping Signal are scouted and are mainly comprised the 1. scouting of frequency set and frequency hopping pattern, the 2. direction finding of Frequency Hopping Signal, and 3. Frequency Hopping Signal detects receipts.
Because it is longer to be used to change cycle of pseudo noise code of carrier frequency, although can obtain its frequency set with quick equipment, but obtain very difficulty of its key by scouting frequency hopping pattern, Chang Gui Frequency Hopping Signal is detectd receipts and can only be utilized 1. guiding and tracking method like this, promptly utilize miscellaneous equipment to scout out the carrier frequency of Frequency Hopping Signal, reboot and detect receiving unit and detect receipts, 2. use the very complicated channelizing technology of hardware.
And to the direction finding of Frequency Hopping Signal and do not require as detecing receipts and need to catch all signals that therefore more selection is arranged, conventional Frequency Hopping Signal direction-finding method mainly contains following three kinds:
(1) the tracking mode direction finding when the guiding of fast frequency search equipment is arranged;
(2) the waiting type direction finding during the given frequency collection;
(3) the search collision type direction finding during no frequency set prior information.
When the frequency hopping rate of Frequency Hopping Signal was higher, because the restriction of indexs such as the time frequently of changing of direction-finding system, channel settling time, above direction-finding method all was difficult to satisfy high requirement, and guiding is detectd the receipts problem and then is difficult to more solve.
The objective of the invention is to avoid the weak point in the above-mentioned background technology and provide a kind of with Frequency Hopping Signal difference constantly, the frequency spectrum shift that occurs on the different carrier frequency handles to same low frequency, Frequency Hopping Signal direction finding and intercept receiving method based on first-order bandpass sampling that the full detail of Frequency Hopping Signal is remained.And the present invention also has detect suitable with the channelizing fruit of producing effects, the Frequency Hopping Signal direction finding that realizes according to this method with detect the characteristics such as to have equipment simple, and performance is good, and is easy to use, with low cost of receiving integral system.
The object of the present invention is achieved like this, and method of the present invention comprises following technical measures:
(1) utilizing the array df method that common-frequency multi-signal is carried out direction finding handles;
(2) utilize digital beam formation method to suppress the co-channel interference signal, improve the letter of useful signal
Make an uproar (doing) ratio;
When (3) utilizing first-order bandpass sampling, if frequency spectrum is oppositely placed, then signal phase and frequency spectrum are just
Opposite when placing, the direction finding result differs 180 °;
Method of the present invention also comprises the technical measures step:
(1) use broadband Low Medium Frequency filter to cover the frequency hopping scope of Frequency Hopping Signal;
(2) press the optimum sampling frequency selection purposes formula of first-order bandpass sampling:
Determine the Low Medium Frequency frequency of each signal and the frequency of sampling with signal bandwidth and channel spacing
Rate is so that the signal that occurs on different frequency is all moved through first-order bandpass sampling
Same low frequency;
(3) utilize high speed low pass sampling (be higher than Low Medium Frequency filter bandwidht two times) in direction finding
Obtain the frequency hopping pattern of Frequency Hopping Signal simultaneously.
Purpose of the present invention can also reach by following technical measures:
(1) utilizes the skill of broadband Low Medium Frequency filter with the frequency hopping scope of covering Frequency Hopping Signal
Art measure step: broadband Low Medium Frequency filter is divided into one group narrower (wideer than individual channel
Many) the Low Medium Frequency filter, each filter all connect corresponding bandpass sampling with
The frequency-division section processing unit constitutes the broad-band channel system.
(2) utilize high speed low pass sampling (be higher than Low Medium Frequency filter bandwidht two times) in direction finding
Obtain the technical measures step of the frequency hopping pattern scouting of Frequency Hopping Signal simultaneously: direction finding place
The reason part is to adopt with the high speed low pass in the broad-band channel filter bandwidht more than two times
The sample frequency sampling utilizes FFT to obtain the frequency hopping pattern of signal, and obtains surveying at frequency domain
To handling needed covariance matrix, in addition the numeral of high-speed sampling gained is believed
Number carrying out double sampling obtains the low frequency signal of same frequency and detects to receive and handle.
The present invention compares background technology following advantage:
(1) the present invention only increases the Low Medium Frequency filter of corresponding broadband in the array df equipment of routine
Ripple device and numeral filter bundle form integrated test that algorithm can realize Frequency Hopping Signal to
Detect receipts, therefore the equipment made from the inventive method is simple, with low cost.
(2) the present invention can realize the full signal energy of Frequency Hopping Signal is intercepted and captured, its direction finding with detect
The fruit of producing effects is suitable with very complicated channelizing equipment, so performance is good.
3. the inventive method and all easy to use with the equipment of this method manufacturing has popularization and answers
Use value.
Below in conjunction with drawings and Examples the present invention is described in further detail.
Fig. 1 is an embodiments of the invention electricity functional-block diagram.
With reference to Fig. 1, embodiments of the invention are made up of aerial array and duplexer battle array 1, zero-signal source, school 2, multichannel receiver 3, broad-band channel filter 4, frequency synthesizer 5, bandpass sampling and frequency-division section processor 6, sampling clock generator 7, integrated treatment and watch-dog 8.Wherein embodiment multichannel receiver 3 is made of 8 and the multichannel receiver 3-1 to 3-8 that connects, 2 bandwidth of each multichannel receiver 3-1 to 3-8 serial connection are broad-band channel filter 4-1-1,4-1-2 to 4-8-1, the 4-8-2 of 10MHz, each broad-band channel filter 4-1-1 to 4-8-1 connects bandpass sampling and frequency-division section processor 6-1, and each broad-band channel filter 4-1-2 to 4-8-2 connects bandpass sampling and frequency-division section processor 6-2.
The principle of implementing the inventive method is as follows: determine that according to characteristic and best first-order bandpass sampling frequency selection purposes formula that the Frequency Hopping Signal Frequency point occurs IF-FRE and sample frequency make the signal that occurs all move same low frequency through first-order bandpass sampling on different frequency.The centre frequency of supposing bandpass signal is ω
C, bandwidth is 2 ω
B, by the first-order bandpass sampling theorem as can be known, [0, ω
Cω
B] in can place m the positive frequency spectrum of signal at most,
Wherein [X] expression is no more than the maximum integer of X, when choosing sampling frequency displacement coefficient n and satisfy 0≤n≤m, can get the optimum sampling frequencies omega
0For
Consider the indirect problem of first-order bandpass sampling during design, promptly how to determine the centre frequency of each signal, could all move same low frequency to the signal on all Frequency points by an identical sample frequency.By formula (2) as can be known, as long as select
Get final product.So at first determine sample frequency ω according to Frequency Hopping Signal bandwidth and channel spacing
0, determine the center frequency points of each Low Medium Frequency signal then by formula (3), determine good center frequency points among the embodiment after, design the local frequency of corresponding multichannel receiver 3.At this moment, the centre frequency of sampling back Frequency Hopping Signal all is shifted to ω
0On/4 the low frequency.
Because ω
0Choose and will guarantee that signal does not have and mix repeatedly, therefore may be greater than channel spacing, at this moment for making a part of ω
CWith ω
0Satisfy formula (3), should get ω
0Be two times channel spacing, this moment another part ω
CSatisfy
This is the reverse situation of placing of signal spectrum just.Frequency spectrum oppositely place to the direction finding did not influence (just since phase place be contrary, and make 180 ° of positive good jobs of direction finding result), only influential to the demodulation of some particular modulation type signal.
Because the signal in the broad-band channel filter bandwidht is all moved centre frequency after bandpass sampling and 6 samplings of frequency-division section processor be ω
0On/4 the low frequency, therefore inevitably a plurality of signals can appear in handling bandwidth, at this moment in bandpass sampling and frequency-division section processor 6, utilize common direction finding processing method to handle, calculate and need to utilize the array processing method that many signal handling capacities are arranged that the many signals after sampling are carried out direction finding, array df is handled and is adopted Multiple Signal Classification method (MUSIC) and weighting subspace fitting method (WSF) to carry out the direction finding processing among the embodiment, and they have the enough robustnesss of unknown rf frequency.
Have a plurality of signals in the processing bandwidth among the embodiment after the sampling, the receipts of detecing to Frequency Hopping Signal have just constituted interference like this, and being detectd receipts, Frequency Hopping Signal needs certain noise (doing) ratio, at this moment to utilize digital beam to form and curb interference signal, useful Frequency Hopping Signal be carried out signal interference ratio strengthen.Because identical sampling time delay is to the phase shift difference of the signal generation of different carrier frequency, and the Frequency Hopping Signal carrier frequency is unpredictable, thereby the wave beam of this moment forms, and can not to adopt the inventor be the method based on the first-order bandpass sampling time delay that proposes in 97118773.8 in the Chinese patent patent No., embodiment adopts in bandpass sampling and frequency-division section processor 6 and realizes that comparatively complicated conventional digital waveform established law forms beam directional figure, to obtain having the signal of higher signal interference ratio, be used for demodulation.
When utilizing a broadband Low Medium Frequency filter 4 to cover whole frequency hopping bandwidth, can produce two problems, the one, in the actual environment for use, electromagnetic spectrum density is higher, and the interference signal number in whole frequency hopping bandwidth might surpass wave beam and form the limit that suppresses number to disturbing, and can't effectively detect receipts, the 2nd, Frequency Hopping Signal is separated timing need handle higher signal to noise ratio than direction finding, and the noise synergistic effect during owing to sampling is when signal is more weak, signal to noise ratio may be too low, so that can't demodulation.For overcoming the above problems, need utilize the broad-band channel technology, whole frequency hopping bandwidth is divided into the P sub-frequency bands, each sub-band is covered by a Low Medium Frequency filter correspondingly, same bandpass sampling and frequency-division section processor 6 are received in the output of one group of corresponding (covering similar frequency bands) filter, in each bandpass sampling and frequency-division section processor 6, do and cover the direction finding in the bandwidth and detect the receipts processing, result to each frequency-division section is carried out compound splicing in integrated treatment and watch-dog 8 then, obtains total direction finding and detects the receipts result.P elects 2 as among the embodiment, and the broad-band channel filter is respectively 4-1-1,4-1-2 to 4-8-1,4-8-2.
When selected processor performance very high (fast operation), at this moment can carry out the sampling of high speed low pass to the output of broad-band channel filter 4, sampled signal is done rapid fourier change (FFT), can obtain the frequency hopping pattern of Frequency Hopping Signal, carry out windowing (mainly removing the frequency spectrum of useless interference signal) at frequency domain and handle the covariance matrix that can obtain the required signal of direction finding processing.In addition, the high-speed sampling signal is carried out double sampling, can obtain the low frequency signal of same frequency, and detect to receive and handle.In bandpass sampling and frequency-division section processor 6, use the sample frequency of 25MHz that the output of broad-band channel filter 4 is sampled among the embodiment, after obtaining frequency hopping pattern by frequency range, go again that the result to bandpass sampling and frequency-division section processor 6-1 and 6-2 carries out compound splicing in integrated treatment and the watch-dog 8, obtain total frequency hopping pattern.Being used to detect the double sampling frequency of receiving processing is 50kHz.
Aerial array and 8 of duplexer battle array 1 usefulness are positioned at space diverse location bay the ELECTROMAGNETIC RADIATION SIGNATURE such as frequency hopping of spatial transmission are received in the embodiment of the invention, input to multichannel receiver 3, multichannel receiver 3 is delivered to broad-band channel filter 4 through frequency conversion and after amplifying, input bandpass sampling and frequency-division section processor 6 are moved same low frequency with first-order bandpass sampling after frequency-division section filtering.The embodiment of the invention works in the ultrashort wave frequency range, mainly to 30 to 88MHz Frequency Hopping Signal direction finding with detect receipts, the bandwidth of this frequency range Frequency Hopping Signal is generally 16kHz, the Frequency Hopping Signal channel spacing is generally 25kHz, interval between each Frequency point in the frequency set of this Frequency Hopping Signal should be elected 2 times channel spacing as, be 50kHz, know that by formula (3) preceding each Frequency Hopping Signal of bandpass sampling should appear at 62.5kHz on low frequency, 112.5kHz, 162.5kHz going up, equifrequent point (or knows when frequency spectrum is oppositely placed by formula (4), each Frequency Hopping Signal appears at 37.5kHz on low frequency, 87.5kHz, 137.5kHz on the equifrequent point), by first-order bandpass sampling its centre frequency is all moved 12.5kHz.
2 its effects of zero-signal source, school are the calibrating signals that produce on the required direction finding frequency, select to be input to each channel of multichannel receiver 3 by aerial array and duplexer battle array 1, with the amplitude and the phase place inconsistency of calibration channel.Frequency synthesizer 5 is used to provide the local vibration source frequency signal of multichannel receiver 3, expansion for the ease of channel number, the local vibration source signal adopts the mode of serial connection along separate routes, promptly the local vibration source signal of N-1 channel is that local oscillation signal by N channel provides, and makes broad-band channel filter 4 cover corresponding frequency hopping bandwidth.The effect of broad-band channel filter 4 is that frequency-division section covers whole frequency hopping bandwidth among the embodiment, makes to obtain whole frequency hopping points, again can lessen any interference and noise to direction finding with detect the influence of receipts.
The effect of bandpass sampling and frequency-division section processor 6 is that bandpass sampling (also can carry out the sampling of high speed low pass when needs are scouted frequency hopping pattern) is carried out in the output of corresponding broad-band channel filter 4, and the array df that the signal in this frequency range carries out common-frequency multi-signal handled and forms digital beam, useful Frequency Hopping Signal is detectd to receive handle (when the high speed low pass is sampled, also can obtain frequency hopping pattern).7 effects of sampling clock generator are the needs according to system, produce required sampled clock signal.The result who handles through bandpass sampling and frequency-division section processor 6 inputs to integrated treatment and watch-dog 8 and carries out compoundly handling with splicing, finishes direction finding and detects receipts.Integrated treatment and watch-dog 8 also are used for the monitoring of entire equipment.
Claims (3)
1. Frequency Hopping Signal direction finding and intercept receiving method based on a first-order bandpass sampling may further comprise the steps:
(1) utilizing the array df method that common-frequency multi-signal is carried out direction finding handles;
(2) utilize digital beam formation method to suppress the co-channel interference signal, improve the letter of useful signal
Make an uproar (doing) ratio;
When (3) utilizing first-order bandpass sampling, if frequency spectrum is oppositely placed, then signal phase and frequency spectrum are just
Opposite when placing, the direction finding result differs 180 °;
It is characterized in that further comprising the steps of:
(1) use broadband Low Medium Frequency filter to cover the frequency hopping scope of Frequency Hopping Signal;
(2) press the optimum sampling frequency selection purposes formula of first-order bandpass sampling:
Determine the Low Medium Frequency frequency of each signal and the frequency of sampling with signal bandwidth and channel spacing
Rate is so that the signal that occurs on different frequency is all moved through first-order bandpass sampling
Same low frequency;
(3) utilize high speed low pass sampling (be higher than Low Medium Frequency filter bandwidht two times) in direction finding
Obtain the frequency hopping pattern of Frequency Hopping Signal simultaneously.
2. Frequency Hopping Signal direction finding and intercept receiving method based on first-order bandpass sampling according to claim 1, it is characterized in that utilizing the step of broadband Low Medium Frequency filter with the frequency hopping scope of covering Frequency Hopping Signal: broadband Low Medium Frequency filter is divided into the Low Medium Frequency filter of a group narrower (much wideer than individual channel), each filter all connects corresponding bandpass sampling and frequency-division section processing unit, constitutes the broad-band channel system.
3. Frequency Hopping Signal direction finding and intercept receiving method based on first-order bandpass sampling according to claim 1 and 2, the step that the frequency hopping pattern that it is characterized in that utilizing high speed low pass sampling (be higher than Low Medium Frequency filter bandwidht two times) to obtain Frequency Hopping Signal in direction finding is scouted: the direction finding processing section be with more than two times in the high speed low pass sample frequency sampling of broad-band channel filter bandwidht, utilize rapid fourier change (FFT) to obtain the frequency hopping pattern of signal, and obtain direction finding at frequency domain and handle needed covariance matrix, in addition the digital signal of high-speed sampling gained is carried out double sampling and obtain the low frequency signal of same frequency and detect to receive and handle.
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| CN98101616A CN1053304C (en) | 1998-04-22 | 1998-04-22 | Frequency-hopping signal direction finding and intercept receiving method based on first-order bandpass sampling |
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| CN100442772C (en) | 2005-10-19 | 2008-12-10 | 华为技术有限公司 | A bridge forwarding method |
| CN101127696B (en) | 2006-08-15 | 2012-06-27 | 华为技术有限公司 | Data forwarding method for layer 2 network and network and node devices |
| JP6212043B2 (en) * | 2011-09-15 | 2017-10-11 | サムスン エレクトロニクス カンパニー リミテッド | Apparatus and method for selecting a beam in a beamforming based wireless communication system |
| CN106788505B (en) * | 2016-11-29 | 2019-02-15 | 西安空间无线电技术研究所 | A kind of processing method of radiometer broadband signal |
| CN109981136B (en) * | 2019-03-21 | 2020-10-09 | 西安电子科技大学 | A method, device and computer storage medium for capturing a frequency hopping communication signal |
| CN113507332B (en) * | 2021-07-08 | 2022-05-06 | 四川九洲电器集团有限责任公司 | Frequency hopping broadband multi-network signal detecting and receiving method and system |
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