CN111175696A - Single-base-station ultra-wideband AOA (automatic optical inspection) positioning method based on frequency modulated continuous waves - Google Patents
Single-base-station ultra-wideband AOA (automatic optical inspection) positioning method based on frequency modulated continuous waves Download PDFInfo
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- CN111175696A CN111175696A CN202010276611.4A CN202010276611A CN111175696A CN 111175696 A CN111175696 A CN 111175696A CN 202010276611 A CN202010276611 A CN 202010276611A CN 111175696 A CN111175696 A CN 111175696A
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- 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
- G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
- G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
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Abstract
The invention discloses a single-base-station ultra-wideband AOA (automatic optical access) positioning method based on frequency modulation continuous waves, wherein a positioning label sends frequency modulation continuous waves, a single-base-station ultra-wideband positioning system based on a linear antenna array receives signals sent by the positioning label, then frequency mixing processing is carried out, then high-frequency signals are filtered, frequency differences between the signals received by two adjacent antenna units are obtained, the distance difference of the signals reaching each antenna unit can be calculated through a derivation formula of the frequency differences, and then the arrival angle AOA is calculated by utilizing a trigonometric function according to the geometric relation of the antenna units. The invention has simple realization process, small calculation amount, no need of accurate synchronous clock and higher calculation result precision.
Description
Technical Field
The invention relates to the field of single-base-station antenna arrival angle positioning methods, in particular to a single-base-station ultra-wideband AOA positioning method based on frequency modulated continuous waves.
Background
In a single-base-station ultra-wideband (UWB) positioning system formed by antenna linear arrays, signals sent by positioning labels are received through the antenna linear arrays, then the arrival angle AOA is calculated according to the distance between the antenna linear arrays and the positioning labels and the direction information of antenna beams, and then the mobile positioning labels are positioned by utilizing a dynamic tracking algorithm. When a traditional single-base-station ultra-wideband (UWB) positioning system calculates the AOA, each antenna unit in an antenna linear array is required to have very accurate clock synchronization, but the problems of time error and delay among the antenna units cannot be solved, so that the calculated AOA has the problem of low accuracy.
Disclosure of Invention
The invention aims to provide a single-base-station ultra-wideband AOA (automatic optical access) positioning method based on frequency-modulated continuous waves, which aims to solve the problems of larger error and low precision in the AOA estimation of the angle of arrival in the prior art.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a single-base-station ultra-wideband AOA positioning method based on frequency modulation continuous waves is characterized in that in a single-base-station ultra-wideband positioning system, signals sent by a positioning label are received by an antenna linear array, and the method comprises the following steps:
(1) enabling the positioning tag to send frequency modulation continuous wave signals to the antenna linear array, and enabling each antenna unit in the antenna linear array to respectively receive the frequency modulation continuous wave signals;
(2) processing the signals received by each antenna unit to obtain the difference frequency between the signals received by any two adjacent antenna unitsf 0；
(3) And (3) utilizing the difference frequency obtained in the step (2)f 0The difference delta of the arrival distance of the frequency modulation continuous wave signal to any two adjacent antenna units is calculated according to the following formular：
In the formula, c is the propagation speed of the electromagnetic wave in the free space, T is the period of the frequency modulation continuous wave signal, and delta F is the bandwidth of the frequency modulation continuous wave signal;
(4) using the difference Δ in arrival distance calculated in step (3)rThen, according to the geometric relationship of each antenna unit in the antenna linear array, the arrival angle AOA of the frequency modulation continuous wave signal reaching any one antenna unit is calculated by utilizing a trigonometric function,let the angle of arrival AOA beθThe formula is as follows:
in the formula, the first and second images are shown,dand (4) accurately positioning the label by combining other distance measurement algorithms according to the distance between any two antenna units and the obtained arrival angle AOA.
The frequency modulation continuous wave-based single-base-station ultra-wideband AOA positioning method is characterized in that in the step (1), as the distance between each antenna unit in the antenna linear array is close, the frequency modulation continuous wave signals sent to the antenna linear array by the positioning tag are regarded as plane wave signals, and therefore the arrival distance difference delta of the frequency modulation continuous wave signals to any two adjacent antenna units isrThe same is true.
The single-base-station ultra-wideband AOA positioning method based on frequency modulated continuous waves is characterized in that in the step (1), a positioning tag sends frequency modulated continuous wave signals to an antenna linear array and selects triangular wave signals.
The frequency modulation continuous wave-based single-base-station ultra-wideband AOA positioning method is characterized in that in the step (2), signals received by any two adjacent antenna units are firstly subjected to frequency mixing processing, then high-frequency signals in the frequency mixing signals are filtered, and then difference frequency between the signals received by any two adjacent antenna units can be obtainedf 0。
The single-base-station ultra-wideband AOA positioning method based on frequency modulated continuous waves is characterized in that positioning of a static positioning label or a positioning label which is considered to be static at the current moment is achieved by using the arrival angle AOA obtained by calculation in the step (4) and combining other ranging algorithms.
The single-base-station ultra-wideband AOA positioning method based on frequency modulated continuous waves is characterized in that other distance measurement algorithms are TOA positioning algorithms or TOF positioning algorithms.
The single-base-station ultra-wideband AOA positioning method based on frequency modulated continuous waves is characterized in that when a positioning label moves, dynamic positioning of the moving positioning label is achieved by using the calculated arrival angle AOA of each time point when the positioning label moves and combining a dynamic tracking algorithm.
The single-base-station ultra-wideband AOA positioning method based on frequency modulated continuous waves is characterized in that the dynamic tracking algorithm can adopt an LMS algorithm or a Kalman filtering algorithm.
The AOA algorithm calculates the arrival angle AOA through the difference frequency of the signals received by the adjacent antenna units, and compared with the traditional AOA algorithm, the AOA algorithm has the advantages of simple implementation process, small calculation amount, no need of an accurate synchronous clock, no introduction of time error and higher accuracy of the calculation result.
Drawings
FIG. 1 is a block flow diagram of the method of the present invention.
Fig. 2 is a schematic diagram of a model of a linear array of antennas in an embodiment of the invention.
Fig. 3 is a time-frequency curve diagram of signals received by any two adjacent antennas according to an embodiment of the present invention.
Detailed Description
The invention is further illustrated with reference to the following figures and examples.
As shown in fig. 1, the method for single-base-station ultra-wideband AOA positioning based on frequency modulated continuous waves, in a single-base-station ultra-wideband positioning system, where a linear array of antennas receives a signal sent by a positioning tag, includes the following steps:
(1) enabling the positioning tag to send frequency modulation continuous wave signals to the antenna linear array, and enabling each antenna unit in the antenna linear array to respectively receive the frequency modulation continuous wave signals;
(2) firstly, carrying out frequency mixing processing on signals received by any two antenna units, then filtering high-frequency signals in the frequency mixing signals to obtain difference frequency between the signals received by any two adjacent antenna unitsf 0；
(3) And (3) utilizing the difference frequency obtained in the step (2)f 0The difference delta of the arrival distance of the frequency modulation continuous wave signal to any two adjacent antenna units is calculated according to the following formular：
In the formula, c is the propagation speed of the electromagnetic wave in the free space, T is the period of the frequency modulation continuous wave signal, and delta F is the bandwidth of the frequency modulation continuous wave signal;
(4) and (3) calculating the difference delta of the arrival distance by using the formula (1) in the step (3)rThen, according to the geometric relationship of each antenna unit in the antenna linear array, the arrival angle AOA of the frequency modulation continuous wave signal reaching any one antenna unit is obtained by utilizing trigonometric function calculation, and the arrival angle AOA is set asθThe formula is as follows:
in the formula, the first and second images are shown,dis the spacing between any two antenna elements. According to the obtained Arrival angle AOA, in combination with other ranging algorithms, a TOA (Time 0f Arrival) positioning algorithm and a TOF (Time of flight) positioning algorithm are optimized, and accurate positioning of the label can be achieved.
The principles of the present invention are further illustrated as follows:
in the single-base-station ultra-wideband positioning system, the arrival time and the distance of the incident signal of each antenna unit in the antenna linear array have a simple linear relationship, multi-antenna joint estimation is easy to perform, and an array model using a uniform linear array as a receiver is shown in fig. 2.
In FIG. 2, a single base station ultra-wideband positioning system is formed byNLinear array of antenna elements (in principle)NAngle of arrival AOA) can be calculated for = 2), the distances between adjacent antenna elements are alldIn the case that the distance between the mobile node and the base station is so far that the size of the antenna array of the base station can be ignored, the signal sent by the positioning tag to the single-base-station ultra-wideband positioning system can be considered to be a plane wave signal.
The geometrical relationship between the antenna elements of the linear array of antennas can be concluded: the first-arriving signal arrival distances between adjacent antenna elements have the same difference. According to FIG. 2The difference in signal arrival distance between adjacent antenna elements is shown as ΔrThen, each antenna unit satisfies the following relationship:
r n =(n-1)*Δr+r 0n=1,2,…,N(1)，
Δr=d*cosθ(2)，
in the formulas (1) and (2),Nin order to determine the number of the antenna elements,r 0the distance the first-arriving signal reaches the antenna unit 1,r n the first arrival signal arrives at the antenna unitNThe distance of (a) to (b),dis the spacing of the adjacent antenna elements,θis angle of arrival AOA. Due to the spacing of adjacent antenna elementsdAs a constant, it is only required to obtain the difference delta between the arrival distances of the frequency-modulated continuous wave signals to any two adjacent antenna unitsrThe angle of arrival AOA can be calculated.
To obtain the difference in signal arrival distance Δ between adjacent antenna elementsrThe positioning tag is required to transmit Frequency Modulated Continuous Wave (FMCW), and the single base station based on the antenna linear array receives the FMCW signal transmitted by the positioning tag. The present invention takes an FMCW signal as an ideal triangular wave as an example, as shown in fig. 3. Regardless of the influence of spurious amplitude modulation, noise and clutter, when the positioning tag and the single base station are assumed to be relatively static in a short time, the frequency of the FMCW signal transmitted by the positioning tag periodically changes according to the rule of a triangular wave, the time-frequency curve of signals received by two adjacent antenna units is shown in (a) in fig. 3, and the time-frequency curve of the corresponding difference frequency signal is shown in (b) in fig. 3.
Because the time-frequency curve shapes of the received signal and the transmitted signal are the same, only one delay exists in time, the distances between each antenna unit and the positioning tag serving as the transmitting information source are different, the time-frequency curves of the signals received by two adjacent antenna units also have a time difference, as shown in fig. 3, the delay time tau and the arrival distance difference delta of the FMCW signal arriving at any two adjacent antenna unitsrThe relationship is as follows:
τ=Δr/c(3)，
in the formula (3)cTo be in free spaceAnd the triangular relationship contained in (a) in fig. 3 shows:
in the formula (4)f 0In order to be the frequency of the difference frequency,Tfor the period of the triangular wave modulated signal, ΔFFor bandwidth modulation. Combining equation (3) and equation (4) can obtain an equation of the difference of the arrival distance of the FMCW signal to any two adjacent antenna units:
the difference frequency is seen by equation (5)f 0And difference of distance ΔrLinearly in relation to the modulation signal parameter ΔFAndTunder certain conditions, only the difference frequency is measuredf 0Then, the difference Δ between the arrival distances of the FMCW signal to any two adjacent antenna elements can be obtained by equation (5)r. The angle of arrival AOA can be obtained according to the formula (2) that isθ：
The algorithm can obtain more accurate arrival angle AOA, and the calculated arrival angle AOA is combined with a related distance measurement algorithm to realize the positioning of a static positioning label or a positioning label which is considered to be static at the current moment.
When the positioning label moves, the dynamic positioning of the positioning label in the moving process can be realized by utilizing the calculated arrival angle AOA of each time point when the positioning label moves and combining the LMS algorithm or the Kalman filtering algorithm.
The embodiments of the present invention are described only for the preferred embodiments of the present invention, and not for the limitation of the concept and scope of the present invention, and various modifications and improvements made to the technical solution of the present invention by those skilled in the art without departing from the design concept of the present invention shall fall into the protection scope of the present invention, and the technical content of the present invention which is claimed is fully set forth in the claims.
Claims (8)
1. A single-base-station ultra-wideband AOA positioning method based on frequency modulation continuous waves is characterized in that in a single-base-station ultra-wideband positioning system, signals sent by a positioning label are received by an antenna linear array, and the method comprises the following steps:
(1) enabling the positioning tag to send frequency modulation continuous wave signals to the antenna linear array, and enabling each antenna unit in the antenna linear array to respectively receive the frequency modulation continuous wave signals;
(2) processing the signals received by each antenna unit to obtain the difference frequency between the signals received by any two adjacent antenna unitsf 0；
(3) And (3) utilizing the difference frequency obtained in the step (2)f 0The difference delta of the arrival distance of the frequency modulation continuous wave signal to any two adjacent antenna units is calculated according to the following formular：
In the formula, c is the propagation speed of the electromagnetic wave in the free space, T is the period of the frequency modulation continuous wave signal, and delta F is the bandwidth of the frequency modulation continuous wave signal;
(4) using the difference Δ in arrival distance calculated in step (3)rThen, according to the geometric relationship of each antenna unit in the antenna linear array, the arrival angle AOA of the frequency modulation continuous wave signal reaching any one antenna unit is obtained by utilizing trigonometric function calculation, and the arrival angle AOA is set asθThe formula is as follows:
in the formula, the first and second images are shown,dthe distance between any two antenna units can be combined with other ranging algorithms to accurately position the label according to the obtained angle of arrival AOA。
2. The frequency-modulated continuous wave-based single-base-station ultra-wideband AOA positioning method according to claim 1, wherein in step (1), the distance difference Δ between the arrival distances of the frequency-modulated continuous wave signals to any two adjacent antenna units is determined as a plane wave signal by the positioning tag, because the antenna units in the antenna linear array are closer to each otherrThe same is true.
3. The frequency modulated continuous wave based single base station ultra wide band AOA positioning method according to claim 1, wherein in step (1), the positioning tag sends the frequency modulated continuous wave signal to the antenna linear array, and the triangular wave signal is selected.
4. The frequency-modulated continuous wave-based single-base-station ultra-wideband AOA positioning method according to claim 1, wherein in the step (2), the signals received by any two adjacent antenna units are first subjected to frequency mixing processing, and then high-frequency signals in the frequency mixing signals are filtered out, so that the difference frequency between the signals received by any two adjacent antenna units can be obtainedf 0。
5. The frequency-modulated continuous wave-based single-base-station ultra-wideband AOA positioning method according to claim 1, wherein the positioning of the stationary positioning tag or the positioning tag considered stationary at the current time is realized by using the angle of arrival AOA calculated in the step (4) in combination with other ranging algorithms.
6. The frequency modulated continuous wave based single base station ultra wide band AOA positioning method according to claim 5, wherein the other ranging algorithm is a TOA positioning algorithm or a TOF positioning algorithm.
7. The single-base-station ultra-wideband AOA positioning method based on frequency modulated continuous waves according to claim 5, wherein when the positioning tag moves, the dynamic positioning of the moving positioning tag is realized by using the calculated arrival angle AOA of each time point when the positioning tag moves, in combination with a dynamic tracking algorithm.
8. The frequency modulated continuous wave based single base station ultra wide band AOA positioning method according to claim 7, wherein the dynamic tracking algorithm may adopt LMS algorithm or Kalman filtering algorithm.
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| CN114295084A (en) * | 2021-12-28 | 2022-04-08 | 江西理工大学 | Self-adaptive TOF (time of flight) calculation method based on improved tongue line function LMS (least mean Square) algorithm and thickness measurement technology adopting method |
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Cited By (8)
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| CN114295084A (en) * | 2021-12-28 | 2022-04-08 | 江西理工大学 | Self-adaptive TOF (time of flight) calculation method based on improved tongue line function LMS (least mean Square) algorithm and thickness measurement technology adopting method |
| CN114295084B (en) * | 2021-12-28 | 2023-09-26 | 江西理工大学 | Adaptive TOF calculation method based on improved skip tongue line function LMS algorithm and thickness measurement technology adopting method |
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