CN104808171A - Interferometer system with reduced quantity of reception channels - Google Patents
Interferometer system with reduced quantity of reception channels Download PDFInfo
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- CN104808171A CN104808171A CN201510182537.9A CN201510182537A CN104808171A CN 104808171 A CN104808171 A CN 104808171A CN 201510182537 A CN201510182537 A CN 201510182537A CN 104808171 A CN104808171 A CN 104808171A
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- array element
- receiving cable
- phase
- signal
- reference array
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S3/00—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received
- G01S3/02—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received using radio waves
- G01S3/14—Systems for determining direction or deviation from predetermined direction
- G01S3/46—Systems for determining direction or deviation from predetermined direction using antennas spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S1/00—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith
- G01S1/02—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith using radio waves
- G01S1/08—Systems for determining direction or position line
- G01S1/20—Systems for determining direction or position line using a comparison of transit time of synchronised signals transmitted from non-directional antennas or antenna systems spaced apart, i.e. path-difference systems
- G01S1/30—Systems for determining direction or position line using a comparison of transit time of synchronised signals transmitted from non-directional antennas or antenna systems spaced apart, i.e. path-difference systems the synchronised signals being continuous waves or intermittent trains of continuous waves, the intermittency not being for the purpose of determining direction or position line and the transit times being compared by measuring the phase difference
- G01S1/302—Systems in which the direction is determined by using an interferometric type transmitting antenna array
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S3/00—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received
- G01S3/02—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received using radio waves
- G01S3/04—Details
- G01S3/043—Receivers
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- Engineering & Computer Science (AREA)
- Remote Sensing (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Computer Networks & Wireless Communication (AREA)
- Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
- Variable-Direction Aerials And Aerial Arrays (AREA)
Abstract
The invention provides an interferometer system with the reduced quantity of reception channels. The configuration of a receiver and the reception channels is as follows: one array element is selected from M array elements to be used as a reference array element, and the other array elements are used as non-reference array elements; the reference array element is connected with the reception channels; r non-reference array elements are grouped; each group of the array elements are connected with one reception channel; each reception channel is switched between the r array elements through a duplexer and the switching period is T; the switching period is adapted to a stable period of a signal source, and the stable time less than a signal is guaranteed; the switching time of each duplexer is synchronized by a clock. The switching period is divided into r parts; each channel in former each 1/r period is connected with one of each groups of the receiving array elements in sequence; the reference array element and a reference channel are connected in the whole period. Therefore, a time division multiplex access manner is adopted so that the signal receiving is realized by using the fewer reception channels.
Description
Technical field
The invention belongs to interferometer passive location system practical technique field, be specifically related to a kind of interferometer that can reduce receiving cable.
Background technology
Interferometer direction finding foundation electric wave is in advancing, when electric wave from different directions arrives direction estimation antenna array, spatially the phase place of each direction-finder antenna unit reception is different, thus mutual phase differential is also different, by measuring wave phase and phase differential, utilize the relation between phase differential and arrival bearing can solve position angle, the angle of pitch of information source or radiation source, thus realize the location of radiation source.Compared with other detection means, detection instrument has the advantages such as locating speed is fast, miniaturization, is therefore widely used in the Passive Detention Systems such as communication and spaceborne, airborne, missile-borne.
In DF and location, need to record the phase differential between multiple reception array element, and in follow-up process, array number is more, constraint interferometer angle being asked for ambiguity solution problem is stronger, and direction finding precision is higher, can improve direction finding ability during low signal-to-noise ratio simultaneously.Therefore, current interferometer increases reception array number as far as possible under limited aperture condition, increases spatial information amount.In current reception system, receiving between array element and receiving cable is relation one to one, and therefore receiving cable number increases along with array number, this provides for improved the requirement to receiver.Add complicacy and the system power dissipation of receiver on the one hand, on the other hand requirement conforming between multiple receiver channel is significantly improved.
Summary of the invention
In view of this, the invention provides a kind of interferometer system reducing receiving cable, under the condition ensureing interferometer direction finding precision, receiving cable is down to the half about receiving array number, reduce the requirement that system docking receives machine.
For achieving the above object, technical scheme of the present invention is: this system comprises the array be made up of M array element, multiple receiving cable, two phase detectors and angle computer, array is used for the signal that Received signal strength source is sent, an array element is chosen as reference array element from array, remaining array element is non-reference array element, a receiving cable is connected separately with reference to array element, be designated as reference channel, by non-reference array element r one group, often organize non-reference array element and jointly connect a receiving cable, be designated as non-reference passage; Then be total to N number of non-reference passage,
The receiving cable connecting one group of non-reference array element is switched between r non-reference array element by switch, and the switching time of each switch, switching cycle T was less than the steady cycle of signal source by clock synchronous; Switching cycle is equally divided into r part, in every r part time, connects in this group non-reference array element; Reference array element and reference channel keep being connected within the whole cycle.
Each receiving cable connects an analog to digital converter, and for the signal received in receiving cable is converted to digital signal, wherein obtaining digital signal with reference to receiving cable is X
0, the digital signal of i-th non-reference passage acquisition is X
i, wherein r=1 ~ N, the inversion frequency of digital to analog converter is r/T.
The output of each digital to analog converter connects two phase detectors respectively; By X in phase detector
ir sub-sequence X is divided into according to its time sequencing
i1, X
i2..., X
ir, the length of each subsequence is the 1/r of switching cycle; I=1 ~ N; Simultaneously for X
0r sub-sequence X is divided into according to its time sequencing
01, X
02..., X
0r, X
01, X
02..., X
0rlength be the 1/r of switching cycle; By subsequence X
i1, X
i2..., X
irwith subsequence X
01, X
02..., X
0rrespective items carries out conjugate multiplication, respectively the corresponding space phase item R obtained between each non-reference array element and reference array element
i1, R
i2..., R
ir; To R
i1, R
i2..., R
irget phase place and to phase average, the space quadrature obtained between each non-reference array element and reference array element exports in angle computer.
Angle computer utilizes the relation between phase differential and angle, solves position angle and the angle of pitch.
Preferably, r=2.
Beneficial effect:
1, receive array element timesharing in the present invention and connect receiving cable, the reception array element of more than 2 or 2 is connected with a receiving cable timesharing, significantly can reduce the quantity of receiving cable, a reference array element and reference channel are set simultaneously, for providing time-frequency phase reference in subsequent treatment, avoid time phase and space phase aliasing, can effectively extract array manifold phase information.Not reducing on the basis receiving array element quantity, significantly reducing receiving cable quantity, while guarantee positioning precision, reducing the complicacy of receiver.
2, consider the inversion frequency of actual analog to digital converter, adopt 2 to receive array element in the present invention and connect a receiving cable, the receiving cable of half can not only be reduced like this, and the analog to digital converter not needing employing upper frequency can be ensured.
Accompanying drawing explanation
Fig. 1-7 yuan uniform circular array schematic diagram, wherein the solid line connected between array element is baseline;
Fig. 2-receiving cable block diagram;
The block diagram of the interferometer system that Fig. 3-the present invention proposes;
Fig. 4-4 channel receiver sampling and subsequence divide sequential chart.
Embodiment
To develop simultaneously embodiment below in conjunction with accompanying drawing, describe the present invention.
Embodiment 1,
Conveniently the present invention describes, and without loss of generality, for M unit uniform circular array.Suppose there is a space radiation source, be θ relative to the position angle of array, the angle of pitch is
position angle is defined as the projection of information source radiation direction in XOY plane and the angle of X-axis, and the angle of pitch is defined as the angle of information source radiation direction and XOY plane, as shown in Figure 1.Suppose that signal S (t) is for narrow band signal, then array received signal X (t) can be expressed as the response of array to signal, i.e. the product of array steering vector and signal:
In formula, A, ω, Φ
0be respectively the amplitude of signal, angular frequency and first phase, g
0for array element amplitude gain,
for the steering vector of array, T is transposition symbol, [φ
0φ
1φ
6] be the space phase of each array element Received signal strength, for θ and
function, for circle battle array, space phase can be expressed as:
Two receive array element and form a baseline, and as shown in Figure 1, baseline can regard a binary line array as, and the space quadrature between two array elements is:
In formula, R is the radius of array, θ
ifor the angle of each array element-circle center line connecting and X-axis, λ is signal wavelength,
for the distance between array element i, j.As long as therefore obtain [φ
0φ
1φ
6] or phase difference
i-φ
j, just can according to (2) or (3) obtain θ and
thus realize the location of radiation source.
In actual applications, space phase is often difficult to directly obtain, and general space quadrature solves angle.Due to the demand of Used for Unwrapping Phase Ambiguity and the requirement of raising positioning precision, need to increase reception array element quantity M, receiving cable quantity also increases thereupon, and this will bring two problems: 1, the increase of receiving cable causes receiver complicacy significantly to improve; 2, there is inconsistency in interchannel, and the increase of receiving cable causes the impact of interchannel inconsistency on direction finding more serious.Therefore, reception array element quantity and receiving cable quantity define conflict group.
Receive array element timesharing and connect receiving cable, the reception array element of more than 2 or 2 is connected with a receiving cable timesharing, effectively can reduce the quantity of receiving cable, a reference array element and reference channel are set simultaneously, for providing time-frequency phase reference in subsequent treatment, avoid time phase and space phase aliasing, can effectively extract array manifold phase information.Not reducing on the basis receiving array element quantity, significantly reducing receiving cable quantity, while guarantee positioning precision, reducing the complicacy of receiver.
Embodiment 2,
Receiver and receiving cable configuration in the present invention: choose an array element in M array element as reference array element, remaining array element is non-reference array element, reference array element is connected with reference channel, non-reference array element one group between two, often organize array element and connect a receiving cable, each receiving cable is switched between two array element by diplexer, switching cycle is T, switching cycle should adapt with the steady cycle of signal source, and ensureing the stationary time being less than signal, the switching time of each diplexer passes through clock synchronous.Be divided into two by switching cycle, in front half period, each expanding channels often organizes one that receives in array element, and switch to another array element in rear half period, reference array element and reference channel keep being connected within the whole cycle.Can, by the mode of time-sharing multiplex, realize realizing Signal reception with less receiving cable like this.
Signal sampling: after receiver amplification, mixing, low pass, A/D, as Fig. 2, in switching cycle T, each receiving cable exports a digital signal sequences, suppose that signal length is l, segmentation is carried out in the output of each passage, and wherein the first half of each sequence is expressed as subsequence 1.
Phase place is asked for: owing to the reference channel after segmentation and the time phase between non-reference passage being alignment, therebetween difference is only the space phase that the angle of pitch in spacing wave source and position angle produce, and therefore utilizes this feature can in the hope of the space quadrature between each array element and reference array element.The subsequence 1 of each passage, subsequence 2 are done conjugate multiplication with the subsequence 1 of reference channel, subsequence 2 respectively.In the signal that conjugate multiplication obtains, because item ω t time phase in phase place is eliminated, phase bit position is remaining space quadrature between each passage subsequence and reference channel subsequence only, the space quadrature namely between each array element and reference array element.Signal after conjugate multiplication is averaged, reduces the impact of noise, then utilize phase detector to carry out phase place to it and ask for, the space quadrature of each array element to signal can be obtained, finally utilize the relation between phase differential and angle to solve azimuth angle theta and the angle of pitch
The block diagram of the interferometer system of the present embodiment as shown in Figure 3.
Embodiment 2:
Embodiments of the present invention for convenience of description, are described for 7 yuan of uniform circular arrays below.The present invention is not limited only to this array, is applicable to various array.
As shown in Figure 1, scheme comprises 7 and receives array element and 4 receiving cables array configurations mode, and receiving cable as shown in Figure 2.Wherein 0# array element is connected with reference to receiving cable, 1# and 2# array element shares No. 2 passages, 3# and 4# array element shares No. 3 passages, 5# and 6# array element shares No. 4 passages.Wherein each receiving cable connects two reception array elements by diplexer timesharing.
2, by after receiver process and A/D, obtain 4 railway digital signals, represent the signal received through 0#-6# array element respectively: [X
0x
1x
2x
3].
3, by [X
0x
1x
2x
3]
tbe divided into two subsequences respectively, the half in the cycle that the length of each subsequence and array element switch, obtains [X
01x
02x
11x
12x
21x
22x
31x
32], as shown in Figure 4.
4, X
11, X
21, X
31respectively with X
01conjugate multiplication, obtains R
10, R
20, R
30; X
12, X
22, X
32respectively with X
02conjugate multiplication, obtains R '
10, R '
20, R '
30.In R, cancellation item time phase, only remains the space quadrature between array element.
5, to R
10, R
20, R
30, R '
10, R '
20, R '
30get phase place and to phase average, the space quadrature between each array element and reference array element can be obtained: (φ
1-φ
0), (φ
2-φ
0) (φ
3-φ
0), (φ
4-φ
0), (φ
5-φ
0), (φ
6-φ
0), with reference to (3).
6, utilize the relation between phase differential and angle, as (2) or (3), solve angle θ and
In concrete operations, the corresponding relation between array element and passage can in the light of actual conditions flexible configuration, and as 7# array element connects with reference to receiving cable, 1# and 6# array element shares No. 1 passage, 2# and 5# array element shares No. 2 passages, 3# and 4# array element shares No. 3 passages.。
To sum up, these are only preferred embodiment of the present invention, be not intended to limit protection scope of the present invention.Within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (2)
1. one kind is reduced the interferometer system of receiving cable, it is characterized in that, this system comprises the array be made up of M array element, multiple receiving cable, two phase detectors and angle computer, described array is used for the signal that Received signal strength source is sent, an array element is chosen as reference array element from array, remaining array element is non-reference array element, a receiving cable is connected separately with reference to array element, be designated as reference channel, by non-reference array element r one group, often organize non-reference array element and jointly connect a receiving cable, be designated as non-reference passage; Then be total to N number of non-reference passage,
The receiving cable connecting one group of non-reference array element is switched between r non-reference array element by switch, and the switching time of each switch, switching cycle T was less than the steady cycle of signal source by clock synchronous; Switching cycle is equally divided into r part, in every r part time, connects in this group non-reference array element;
Described reference array element and reference channel keep being connected within the whole cycle;
Each receiving cable connects an analog to digital converter, and for the signal received in receiving cable is converted to digital signal, wherein obtaining digital signal with reference to receiving cable is X
0, the digital signal of i-th non-reference passage acquisition is X
i, wherein r=1 ~ N, the inversion frequency of described digital to analog converter is r/T;
The output of each digital to analog converter connects two phase detectors respectively; By X in described phase detector
ir sub-sequence X is divided into according to its time sequencing
i1, X
i2..., X
ir, the length of each subsequence is the 1/r of described switching cycle; I=1 ~ N; Simultaneously for X
0r sub-sequence X is divided into according to its time sequencing
01, X
02..., X
0r, X
01, X
02..., X
0rlength be the 1/r of described switching cycle; By subsequence X
i1, X
i2..., X
irwith subsequence X
01, X
02..., X
0rrespective items carries out conjugate multiplication, respectively the corresponding space phase item R obtained between each non-reference array element and reference array element
i1, R
i2..., R
ir; To R
i1, R
i2..., R
irget phase place and to phase average, the space quadrature obtained between each non-reference array element and reference array element exports in angle computer;
Described angle computer utilizes the relation between phase differential and angle, solves position angle and the angle of pitch.
2. a kind of interferometer system reducing receiving cable as claimed in claim 1, is characterized in that, r=2.
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| CN201510182537.9A CN104808171B (en) | 2014-12-19 | 2015-04-16 | A kind of interferometer system for reducing receiving channel |
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| CN2014107979874 | 2014-12-19 | ||
| CN201410797987 | 2014-12-19 | ||
| CN201510182537.9A CN104808171B (en) | 2014-12-19 | 2015-04-16 | A kind of interferometer system for reducing receiving channel |
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Cited By (2)
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| CN110007267A (en) * | 2019-01-29 | 2019-07-12 | 杭州电子科技大学 | A kind of uniform circular array interferometer direction finding ambiguity solution method based on mixed baseline |
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Cited By (4)
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| CN110007267A (en) * | 2019-01-29 | 2019-07-12 | 杭州电子科技大学 | A kind of uniform circular array interferometer direction finding ambiguity solution method based on mixed baseline |
| CN110007267B (en) * | 2019-01-29 | 2020-08-18 | 杭州电子科技大学 | Uniform circular array interferometer direction finding ambiguity resolving method based on mixed base line |
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