CN102819016A - Passive detection system and method for detecting low-altitude target by using navigation radar signals - Google Patents

Abstract

The invention discloses a passive detection system for detecting a low-altitude target by using navigation radar signals and relates to the field of passive radars. The passive detection system comprises a non-cooperative navigation radar, a passive receiving system, a signal information processing module and a geographic information module used for displaying positioning results. The invention further discloses a method for passively positioning the low-altitude target by using the navigation radar. The method includes steps that: 1 the passive receiving system measures arrival angles of a direct arrival signal and a target echo; 2 direct arrival pulses are adopted to estimate the azimuth angle of a navigation radar emitting antenna scanning from a direct arrival path to a target reflection path; 3 the signal information processing module is adopted to obtain time delay of the target echo relative to the direct arrival signal; 4 measurement is obtained, a triangle formed by the navigation radar, the target and the passive receiving system is solved and three-dimensional coordinates of the target are obtained; and 5 the target position is given on an electronic map. The passive detection system and method have the capability of detecting the low-altitude target for maintaining electromagnetic silence and can achieve situation monitoring and early warning.

Description

Utilize the passive detection system and the method for navar acquisition of signal low target

One, technical field

The invention belongs to the passive radar technical field, particularly the movement overseas platform utilizes the passive detection technology of navar signal to low target.

Two, background technology

In modern times in the war, because the development of electronic attack technology, the monostatic radar radar system is being faced with advanced weaponries such as antiradiation missile, invisbile plane, and the serious day by day threats of means of warfare such as integrated electronics interference, low-level penetration.Therefore to improve the viability of radar, give full play to the usefulness of radar, must comprehensively adopt various countermeasure.

In traditional monostatic radar field, many antagonism four big measures that threaten have been proposed, comprise that the signal waveform that adopts particular design realizes that the low maneuverability of intercepting and capturing, improve radar prevents the attack of antiradiation missile etc.Yet,, pre-warning time is shortened because the restriction of earth curvature makes monostatic radar reduce the effective detection range of the cruise missile of hedgehopping.When for realization low target being surveyed the low-altitude dish beam configuration that adopts, the feeble signal of low target reflection is hidden in the land clutter noise, is difficult to differentiate.And the signal that self radiation source of target that utilizes a plurality of receiving stations to intercept and capture is launched comes the passive radar to target localization, is the effective measures of antagonism antiradiation missile.It arrives time delay and the angle of arrival parameter that each is stood through the measurement target signal, confirms the position of radiation source and carrier platform thereof (target).But when target is taked radio listening silence and do not transmitted, this passive radar will lose efficacy.

The most promising countermeasure is exactly that self does not launch electromagnetic signal; But utilize the reflected signal of electromagnetic signal on target of launching for other purposes in the environment; Obtain Doppler shift, step-out time and the angle of arrival etc. of target echo, thereby realize passive radar system target detection and location.When the radar of this system can keep " mourning in silence " in target, passive receiving station still can survey and follow the tracks of target.Research based on the continental rise passive detection system of TV DTV or frequency modulation broadcasting DAB, Wimax and signals such as Wifi local area network signal, GSM mobile handset has obtained significant achievement, has caused widely to pay close attention to.Its typical case's representative is " the reticent sentry " of U.S.'s development, and it made one's first appearance in the exhibition of Washington on October 12nd, 1998.Up to the present, existing many continental rise passive detection systems that concentrate on based on signals such as radio and television come out.Yet; By contrast; Sea region outside; Because motion platform receives the restriction of signal capable of using, do not see the report of studying carrier-borne, as to dive movement overseas platforms such as carrying passive detection system as yet, main cause is because possibly receive civil signal such as radio and television hardly in the marine site away from seashore hundreds of kilometer.

Along with the development of global maritime shipping industry, the IMO of International Maritime Organization (IMO) regulation, for fear of bumping against with other ships and to fixing waterborne target, most naval vessels all must be equipped with navar.Navar has spread on the private spitkit at present.And on large-scale cargo ship, must be equipped with the navar of a plurality of different-wavebands.At each marine busy navigation channel and harbour,, also have and be furnished with the navar of keeping watch on maritime traffic for the safety of shipping.Navar radiation source on all these platforms be carrier-borne, dive carrying etc. that the passive detection of movement overseas Platform Implementation and location provide maybe.

Three, summary of the invention

1. the technical matters that will solve

Technical matters to be solved by this invention is: a kind of system that utilizes the navar signal that low flyers such as cruise missile, extreme low-altitude aircraft are carried out passive detection is provided, its can be used for carrier-borne, supervision and the early warning of movement overseas platform to low latitude or treetop level target such as dive to carry.

The further technical matters to be solved of the present invention is: for movement overseas platform such as carrier-borne, as dive to carry provides a kind of localization method that utilizes the navar signal to low latitude or treetop level target, it can obtain the Three-dimension Target coordinate.

2. technical scheme

For solving the problems of the technologies described above, the present invention adopts following technical measures:

A kind of passive detection system that utilizes navar acquisition of signal low latitude or treetop level target is provided; Comprise non-cooperation navar, passive receiving system, signal message processing module and be used for the geography information module of display-object positioning result that wherein passive receiving system comprises and being used to extract synchronously and the direct wave passage of reference information and the scouting passage that is used to receive supervision spatial domain internal object scattered signal.

A kind of localization method that utilizes the navar signal to low latitude or treetop level target is provided, comprises step:

1. passive receiving system is measured the direct signal of navar and the angle of arrival of target echo;

2. utilize the fluctuation characteristic of direct wave pulse signal to estimate that the navar antenna scans the position angle in target scattering path from direct path;

The signal message processing module utilize navar signal that the direct wave passage intercepts and captures as a reference signal with scout relevant processing of target echo that passage receives, obtain the time delay of the relative direct wave signal of target echo;

4. obtain above-mentioned measurement result, separate the bistatic triangle that constitutes by navar, target and passive receiving system, just can obtain the three-dimensional coordinate of low latitude or treetop level target;

5. on electronic chart, provide the target location.

3. beneficial effect

The invention has the beneficial effects as follows: passive detection system of the present invention has advantages such as search coverage is wide, bearing accuracy is higher, environmental suitability is stronger; The ability of low latitudes such as remote passive detection cruise missile, extreme low-altitude aircraft, hedgehopping device can be provided for movement overseas platform such as carrier-borne, as dive to carry; Can keep watch on and distant early warning for the movement overseas optimal in structure provides situation, have application value in army.

Four, description of drawings

Fig. 1 is a passive detection system synoptic diagram of the present invention.

Fig. 2 is a system space solid geometry graph of a relation of the present invention.

Fig. 3 is the block diagram of the inventive method.

Fig. 4 is the process flow diagram of the time delay and the Doppler shift parameter estimation of target echo signal of the present invention.

Fig. 5 is the synoptic diagram of the concrete application result of the present invention.

Fig. 6 is the concrete positioning result of target on electronic chart that detects of using of the present invention.

Five, embodiment

Below in conjunction with Figure of description the present invention is described in further detail.

As shown in Figure 1; The present invention provides a kind of passive detection system that utilizes navar acquisition of signal low target, comprises non-cooperation navar radiation source, the passive receiving system of binary channels, signal message processing module and is used for the geography information module of display-object positioning result;

Wherein passive receiving system frequency of operation be tuned to during the transmission frequency of non-cooperation navar; The direct wave passage of passive receiving system will detect along baseline and propagate the non-cooperation navar signal that arrives; And its target reconnaissance passage will be intercepted and captured the homology coherent signal of monitor area internal object reflection; The signal of the passive receiving system intercepting and capturing of binary channels is transferred to the signal message processing module then; The direct wave signal carries out sorting and interference suppresses to the direct wave in the target echo signal to receiving; And utilize the signal message processing module that the relative time delay and the Doppler shift of target echo signal to be measured are measured, meanwhile utilize the fluctuation characteristic of the direct wave signal after the sorting that emitting antenna is estimated from the azimuth angle theta t that direct path scans the target scattering path; Utilize the angle of arrival, relative time delay, Doppler shift, the angle of arrival of direct wave signal, the emitting antenna azimuth angle theta of the target echo signal that is obtained then _tInformation is carried out target localization, and forms targetpath; Utilize the geography information module that target localization result and flight path information are presented on the electronic chart at last, form the integrated situational awareness picture of target.

As shown in Figure 2, the present invention also provides a kind of method of utilizing the navar signal to low latitude or treetop level target passive positioning, and embodiment is divided following step:

1. the passive receiving system of binary channels is measured the direct signal of navar and the angle of arrival of target echo;

2. utilize the fluctuation characteristic of direct wave pulse signal to estimate that the navar antenna scans the position angle in target scattering path from direct path;

The signal message processing module utilize navar signal that the direct wave passage intercepts and captures as a reference signal with scout the processing that be concerned with of target echo that passage receives, the time delay of the relative direct wave signal of acquisition target echo;

4. obtain above-mentioned measurement result, separate the bistatic triangle that constitutes by navar, target and passive receiving system, just can obtain the three-dimensional coordinate of low latitude or treetop level target;

5. on electronic chart, provide the target location.

Below provide and utilize the resolving of navar signal low latitude or treetop level target Passive Location.

With passive receiving system position is initial point, calculated target positions in the rectangular coordinate system that non-cooperation navar-target-passive receiving system constitutes, and its space multistory geometric relationship is as shown in Figure 3.Among the figure, R _t, R _rBe respectively navar radiation source and passive receiving system range-to-go, object height is represented with H.θ _t, φ _tThe position angle and the angle of pitch of representing the relative navar of target respectively; θ _r, φ _rBe respectively the position angle and the angle of pitch of the passive relatively receiving system of target; θ _T, θ _RBe respectively the visual angle of the relative navar radiation source of target and passive receiving system on the bistatic plane.Generally speaking, for system of the present invention, the azimuth angle theta of the passive relatively receiving system of target _rWith angle of pitch φ _r, the relative direct wave pulse of target echo bistatic time delay τ can obtain more exactly.Suppose that c is the light velocity, then

R _t+R _r-L＝cτ (1)

Therefore, the orientable precondition of target is exactly θ _tThe two must have a parameter to survey with L.Because for native system, the positional information of non-cooperation navar is that priori is unknown, so L is a unknown parameter.And, utilize the fluctuation characteristic of its direct pulse sequence can estimate azimuth angle theta through comparing the signal of the different lobes emissions of navar antenna _t

By space geometry relation shown in Figure 3, utilize sine, can get

$\frac{L}{\sin ({\mathrm{\θ}}_r-{\mathrm{\θ}}_t)}=\frac{R_{t\⊥}}{\sin {\mathrm{\θ}}_r}=\frac{R_{r\⊥}}{\sin {\mathrm{\θ}}_t}---\left(2\right)$

Wherein, subscript _⊥The expression respective components, can be known again by Fig. 3 in the projection of vertical plane

$R_r=\frac{R_{r\⊥}}{\cos {\mathrm{\φ}}_r}---\left(3\right)$

H＝R _r⊥tanφ _r＝R _rcosφ _rtanφ _r＝R _rsinφ _r (4)

$R_{t\⊥}^2+H^2=R_t^2---\left(5\right)$

cosθ _R＝cosφ _rcosθ _r (6)

$L=\frac{R_r\cos {\mathrm{\φ}}_r}{\sin {\mathrm{\θ}}_t}\sin ({\mathrm{\θ}}_r-{\mathrm{\θ}}_t)---\left(7\right)$

Then

$R_{t\⊥}=\frac{R_r\cos {\mathrm{\φ}}_r\sin {\mathrm{\θ}}_r}{\sin {\mathrm{\θ}}_t}---\left(8\right)$

$R_t=\mathrm{c\τ}+\frac{R_r\cos {\mathrm{\φ}}_r}{\sin {\mathrm{\θ}}_t}\sin ({\mathrm{\θ}}_r-{\mathrm{\θ}}_t)-R_r---\left(9\right)$

H＝R _rsinφ _r (10)

Formula (8), (9), (10) substitution formula (5) are got

${\left[\frac{R_r\cos {\mathrm{\φ}}_r\sin {\mathrm{\θ}}_r}{\sin {\mathrm{\θ}}_t}\right]}^2+{\left[R_r\sin {\mathrm{\φ}}_r\right]}^2={[\mathrm{c\τ}+\frac{R_r\cos {\mathrm{\φ}}_r}{\sin {\mathrm{\θ}}_t}\sin ({\mathrm{\θ}}_r-{\mathrm{\θ}}_t)-R_r]}^2---\left(11\right)$

Separate formula (11) the oblique distance of target does

$R_r=\mathrm{c\&tau;}\frac{\left\{\right[1-\frac{\cos {\mathrm{\&phi;}}_r}{\sin {\mathrm{\&theta;}}_t}\sin ({\mathrm{\&theta;}}_r-{\mathrm{\&theta;}}_t)]+\sqrt{{{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HSA00000519351000041.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2{\mathrm{\&phi;}}_r+\left(\frac{{\cos \mathrm{\&phi;}}_r\sin {\mathrm{\&theta;}}_r}{\sin {\mathrm{\&theta;}}_t}\right)}^2}\}}{{[\frac{\cos {\mathrm{\&phi;}}_r}{\sin {\mathrm{\&theta;}}_t}\sin ({\mathrm{\&theta;}}_r-{\mathrm{\&theta;}}_t)-1]}^2-{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HSA00000519351000041.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2{\mathrm{\&phi;}}_r-{\left(\frac{\cos {\mathrm{\&phi;}}_r\sin {\mathrm{\&theta;}}_r}{\sin {\mathrm{\&theta;}}_t}\right)}^2}---\left(12\right)$

Thereby the object height that is easy to get does

$H=\mathrm{c\&tau;}\frac{\left\{\right[1-\frac{\cos {\mathrm{\&phi;}}_r}{\sin {\mathrm{\&theta;}}_t}\sin ({\mathrm{\&theta;}}_r-{\mathrm{\&theta;}}_t)]+\sqrt{{{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HSA00000519351000041.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2{\mathrm{\&phi;}}_r+\left(\frac{{\cos \mathrm{\&phi;}}_r\sin {\mathrm{\&theta;}}_r}{\sin {\mathrm{\&theta;}}_t}\right)}^2}\}}{{[\frac{\cos {\mathrm{\&phi;}}_r}{\sin {\mathrm{\&theta;}}_t}\sin ({\mathrm{\&theta;}}_r-{\mathrm{\&theta;}}_t)-1]}^2-{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HSA00000519351000041.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2{\mathrm{\&phi;}}_r-{\left(\frac{\cos {\mathrm{\&phi;}}_r\sin {\mathrm{\&theta;}}_r}{\sin {\mathrm{\&theta;}}_t}\right)}^2}\sin {\mathrm{\&phi;}}_r---\left(13\right)$

As shown in Figure 4, the flow process about time delay and Doppler shift parameter estimation in the signal message processing module may further comprise the steps:

(1) direct wave signal delay conjugation and make product with target echo signal;

(2) utilize cic filter that the result of step (1) is extracted, thereby reduce data sampling rate, dwindle the frequency analysis scope, and the result that will extract carries out filtering through low-pass filter;

(3) filtered data are made Fast Fourier Transform (FFT) FFT, thereby obtain estimating at the Doppler shift of this time delay unit;

(4) repeat (1), (2) and (3) process, carry out peak value on mutual ambiguity function plane then and detect, obtain the maximal possibility estimation of target time delay and Doppler shift.

As shown in Figure 5; Be an application example of the present invention; Utilize the signal of the frequency of the navar emission on the commercial passenger traffic steamer, to the bistatic range difference and the Doppler shift results estimated of the relative direct wave signal of target echo in monitor area, intercepted and captured for 9.41GHz.

As shown in Figure 6; For the present invention specifically uses; Utilize the target angle of arrival information that passive detection system obtains and the bistatic range difference and the Doppler shift of target; Resolve the distance of the relative passive detection system of the target that obtains in electronic chart, all found target being respectively 31.5km, 19.7km and 70km place apart from passive detection system at last.

Claims (6)

1. utilize the passive detection system of navar acquisition of signal low target, it is characterized in that: comprise non-cooperation navar, passive receiving system, signal message processing module and geography information module;

When wherein the frequency of operation of passive receiving system is tuned at the transmission frequency of non-cooperation navar radiation source; Highly sensitive passive receiving system will detect along baseline and propagate direct wave signal and the target echo after the scattering of monitor area internal object that arrives; The signal of then passive receiving system being intercepted and captured is transferred to the signal message processing module; Obtain navar direct signal and time delay and Doppler shift through between the same source signal of target reflection; And utilize the signal message processing module, and resolve three-dimensional coordinate, speed, the flight path that obtains low latitude or treetop level target with the target time delay that receives and Doppler shift information and direct wave and the target echo angle of arrival, the parameter pairing of emission visual angle; Utilize the geography information module to preserve the signal message processing module at last and resolve the target position information that obtains at every turn, and on electronic chart, show the positioning result and the flight path of corresponding target.

2. passive detection system as claimed in claim 1 is characterized in that: described navar signal is S, the signal of C or many kinds of frequency ranges of X.

3. passive detection system as claimed in claim 1 is characterized in that: described navar is that navar, bank base harbour surveillance radar, commercial boat-carrying navar are kept watch in maritime traffic.

4. passive detection system as claimed in claim 1 is characterized in that: can be according to the adjustment of the monitor area of the system non-cooperation navar that utilizes of Dynamic Selection adaptively.

5. localization method that utilizes navar acquisition of signal low target, comprise step: 1. passive receiving system is measured the direct signal of navar and the angle of arrival of target echo; 2. utilize the fluctuation characteristic of direct wave pulse signal to estimate that the navar antenna scans the position angle in target scattering path from direct path; The signal message processing module utilize navar signal that the direct wave passage intercepts and captures as a reference signal with scout relevant processing of target echo that passage receives, obtain the time delay of the relative direct wave signal of target echo; 4. obtain above-mentioned measurement result, the bistatic triangle that Xie Youfei cooperation navar, target and passive receiving system constitute just can obtain the three-dimensional coordinate of low latitude or treetop level target; 5. on electronic chart, provide the target location.

6. method as claimed in claim 5 is characterized in that: it can survey aerial and sea-surface target equally, can position aircraft, guided missile, surface ship at a distance.

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