CN104914427A - Adaptive time delay estimation ranging method and system based on received signal strength - Google Patents

Abstract

The invention provides an adaptive time delay estimation ranging method and a system based on received signal strength, which can improve the ranging precision. The method comprises steps: S1, electric field signals and magnetic field signals are acquired, and noise in the electric field signals and the magnetic field signals is eliminated; S2, strength of the electric field signals and strength of the magnetic field signals after the noise is eliminated are determined, and an electromagnetic field time delay estimation value is initially determined; and S3, according to the initially-determined electromagnetic field time delay estimation value, an electromagnetic field time delay initial value is determined, and the electric field signals and the magnetic field signals after the noise is removed are processed, and a communication distance between ranging targets can be determined. The method and the system can be applied to the communication field.

Description

Based on distance-finding method and the system of the adaptive time delay stimation of received signal strength

Technical field

The present invention relates to the communications field, refer to a kind of distance-finding method and system of the adaptive time delay stimation based on received signal strength especially.

Background technology

At present, when finding range near field electromagnetic field, employing adaptive time delay estimation algorithm estimates the time delay between electromagnetic field, and finds range to the communication distance between measuring distance of target according to the relation of the communication distance between the time delay between the electromagnetic field estimated and measuring distance of target.Described adaptive time delay estimation algorithm comprises: traditional adaptive time delay estimation algorithm and the adaptive time delay estimation algorithm of variable step.Wherein, although traditional adaptive time delay estimation algorithm accurately can estimate the time delay between two-way Received signal strength (electric field signal and field signal), but for the situation that time delays constantly changes, it is delayed to there is the regular hour in traditional adaptive time delay estimation algorithm, simultaneously, if need the target of range finding in constantly mobile change, traditional adaptive time delay estimation algorithm can not measure the distance between the target of range finding quickly and accurately.

Compared with traditional adaptive time delay estimation algorithm, the adaptive time delay estimation algorithm of variable step can improve the speed of convergence of adaptive algorithm effectively, improve the tracking performance of algorithm for change system, but the adaptive time delay estimation algorithm of variable step adopts larger step-length to improve speed of convergence in converged state, larger convergence error can be introduced, make the electromagnetic field time delay evaluated error in this stage comparatively large, if the position of measuring distance of target is all the time in change, then range error can be always larger.In addition, due to the impact of noise, when the cost function of adaptive time delay estimation algorithm exists local optimum and global optimum, if initial delay estimated value arranges improper, algorithm can converge on local optimum, makes time delay estimate to occur mistake.

Summary of the invention

The technical problem to be solved in the present invention is to provide a kind of distance-finding method and system of the adaptive time delay stimation based on received signal strength, to solve the problem that electromagnetic field time delay evaluated error is large, range error is large existing for prior art.

For solving the problems of the technologies described above, the embodiment of the present invention provides a kind of distance-finding method of the adaptive time delay stimation based on received signal strength, comprising:

S1: obtain electric field signal and field signal, and eliminate the noise in described electric field signal and field signal;

S2: the intensity determining the electric field signal after stress release treatment and field signal, and tentatively determine electromagnetic field time delay estimated value;

S3: according to the electromagnetic field time delay estimated value determination electromagnetic field time delay initial value tentatively determined, and the carrying out of the electric field signal after denoising and field signal is processed, determine the communication distance between measuring distance of target.

Alternatively, comprise before described S1:

Electromagnetic field time delay initial value is set electromagnetic field time delay difference DELTA _d, number of samples N, the peak-to-average power ratio R transmitted _tX;

Described S1 comprises:

By transmitting terminal, low frequency signal is launched;

Obtain the electric field signal in transmitting by electric field reception antenna and obtain the field signal in transmitting by magnetic field receiving antenna;

The noise in described electric field signal and field signal is eliminated by adaptive threshold noise blanking device;

Electric field signal after stress release treatment and field signal are stored in N number of storage space respectively.

Alternatively, the described noise eliminated in described electric field signal and field signal by adaptive threshold noise blanking device is comprised:

Determine the intensity of electric field signal and the field signal obtained;

According to the electric field signal determined and the intensity of field signal and the peak-to-average power ratio R transmitted of setting _tX, determine the threshold value B of adaptive threshold noise blanking device:

$B=\sqrt{{\left(\frac{R_{TX}}{10}\right)}^{10}E\left(\right|s\left(k\right){|}^2)}$

Wherein, E (| s (k) | ²) represent received signal strength, the signal that s (k) receives for receiving end, described signal comprises: electric field signal and field signal, contains noise in described electric field signal and field signal, and N is number of samples, and the span of k is 1,2 ..., N.

Alternatively, described S2 comprises:

According to the electric field signal stored and field signal, determine the intensity of the electric field signal after stress release treatment and field signal;

According to the propagation formula of low frequency signal, by the intensity of the electric field signal after the stress release treatment determined and field signal, tentatively determine the communication distance between measuring distance of target;

According to the communication distance between measuring distance of target and the relation between electromagnetic field time delay, tentatively determine electromagnetic field time delay estimated value

Alternatively, described S3 comprises:

When time, upgrade the electromagnetic field time delay initial value of adaptive time delay stimation module when do not upgrade the electromagnetic field time delay initial value of adaptive time delay stimation module

According to the electromagnetic field time delay initial value determined and utilize adaptive time delay stimation module to process the electric field signal after stress release treatment and field signal, determine that electromagnetic field time delay estimates final value and upgrade electromagnetic field time delay initial value

If electromagnetic field time delay estimates final value for when definite value or error are in preset range, then estimate final value according to described electromagnetic field time delay determine the communication distance between measuring distance of target;

If electromagnetic field time delay estimates final value be in when constantly changing, then return step S1 and continue to perform.

The embodiment of the present invention also provides a kind of range measurement system of the adaptive time delay stimation based on received signal strength, comprising:

Stress release treatment unit, for obtaining electric field signal and field signal, and eliminates the noise in described electric field signal and field signal;

The preliminary determining unit of time delay, for determining the intensity of the electric field signal after stress release treatment and field signal, and tentatively determines electromagnetic field time delay estimated value;

Communication distance determining unit, for the electromagnetic field time delay estimated value determination electromagnetic field time delay initial value that basis is tentatively determined, and processes the carrying out of the electric field signal after denoising and field signal, determines the communication distance between measuring distance of target.

Alternatively, described system also comprises:

Initialization unit, for arranging electromagnetic field time delay initial value electromagnetic field time delay difference DELTA _d, number of samples N, the peak-to-average power ratio R transmitted _tX;

Described stress release treatment unit comprises:

Signal emission module, for launching low frequency signal by transmitting terminal;

Electric field signal receiver module, for obtaining the electric field signal in transmitting by electric field reception antenna;

Field signal receiver module, for obtaining the field signal in transmitting by magnetic field receiving antenna;

Stress release treatment module, for eliminating the noise in described electric field signal and field signal by adaptive threshold noise blanking device;

Signal storage module, for being stored to the electric field signal after stress release treatment and field signal respectively in N number of storage space.

Alternatively, described stress release treatment module comprises:

Received signal strength determination submodule, for determining the intensity of electric field signal and the field signal obtained;

Blanking interval threshold value determination submodule, for according to the intensity of the electric field signal determined and field signal and the peak-to-average power ratio R transmitted of setting _tX, determine the threshold value B of adaptive threshold noise blanking device:

$B=\sqrt{{\left(\frac{R_{TX}}{10}\right)}^{10}E\left(\right|s\left(k\right){|}^2)}$

Wherein, E (| s (k) | ²) represent received signal strength, the signal that s (k) receives for receiving end, described signal comprises: electric field signal and field signal, contains noise in described electric field signal and field signal, and N is number of samples, and the span of k is 1,2 ..., N.

Alternatively, the preliminary determining unit of described time delay comprises:

Received signal strength determination module, for according to the electric field signal stored and field signal, determines the intensity of the electric field signal after stress release treatment and field signal;

The preliminary determination module of communication distance, for the propagation formula according to low frequency signal, by the intensity of the electric field signal after the stress release treatment determined and field signal, tentatively determines the communication distance between measuring distance of target;

The preliminary determination module of time delay, for according to the communication distance between measuring distance of target and the relation between electromagnetic field time delay, tentatively determines electromagnetic field time delay estimated value

Alternatively, described communication distance determining unit comprises:

Time delay initial value determination module, for working as time, upgrade the electromagnetic field time delay initial value of adaptive time delay stimation module when do not upgrade the electromagnetic field time delay initial value of adaptive time delay stimation module

Time delay final value determination module, for according to the electromagnetic field time delay initial value determined and utilize adaptive time delay stimation module to process the electric field signal after stress release treatment and field signal, determine that electromagnetic field time delay estimates final value and upgrade electromagnetic field time delay initial value

Communication distance determination module, if estimate final value for electromagnetic field time delay for when definite value or error are in preset range, then estimate final value according to described electromagnetic field time delay determine the communication distance between measuring distance of target;

Return execution module, if estimate final value for electromagnetic field time delay be in when constantly changing, then return step S1 and continue to perform.

The beneficial effect of technique scheme of the present invention is as follows:

In such scheme, by the intensity of the electric field signal after stress release treatment and field signal, electromagnetic field time delay estimated value is carried out according to a preliminary estimate, and according to electromagnetic field time delay estimated value determination electromagnetic field time delay initial value according to a preliminary estimate, again the carrying out of the electric field signal after denoising and field signal is processed, thus determine the communication distance between measuring distance of target.Like this, according to electromagnetic field time delay estimated value determination electromagnetic field time delay initial value according to a preliminary estimate, in certain SNR ranges, the impact that cost function local optimum is estimated electromagnetic field time delay can be avoided, and when measuring distance of target is when moving fast, the present invention can constantly update the electromagnetic field time delay initial value of adaptive time delay estimation algorithm according to the intensity of the electric field signal got and field signal, effectively can improve the speed of convergence of adaptive time delay estimation algorithm, electromagnetic field Time delay Estimation Accuracy and distance accuracy.

Accompanying drawing explanation

The method flow diagram of the distance-finding method of the adaptive time delay stimation based on received signal strength that Fig. 1 provides for the embodiment of the present invention;

The structural representation of the transmitting terminal that Fig. 2 provides for the embodiment of the present invention and receiving end;

The time delay that Fig. 3 provides for the embodiment of the present invention and communication distance, relation schematic diagram between path loss and communication distance;

The structural representation of the adaptive time delay stimation module based on received signal strength that Fig. 4 provides for the embodiment of the present invention;

The structural representation of the basic adaptive time delay stimation module that Fig. 5 provides for the embodiment of the present invention;

The adaptive time delay stimation module based on received signal strength that Fig. 6 provides for the embodiment of the present invention is to the optimum results schematic diagram of SETDE algorithm.

Embodiment

For making the technical problem to be solved in the present invention, technical scheme and advantage clearly, be described in detail below in conjunction with the accompanying drawings and the specific embodiments.

The present invention is directed to the problem that existing electromagnetic field time delay evaluated error is large, range error is large, a kind of distance-finding method and system of the adaptive time delay stimation based on received signal strength are provided.

Embodiment one

Shown in Fig. 1, the distance-finding method of a kind of adaptive time delay stimation based on received signal strength that the embodiment of the present invention provides, comprising:

S1: obtain electric field signal and field signal, and eliminate the noise in described electric field signal and field signal;

S2: the intensity determining the electric field signal after stress release treatment and field signal, and tentatively determine electromagnetic field time delay estimated value;

S3: according to the electromagnetic field time delay estimated value determination electromagnetic field time delay initial value tentatively determined, and the carrying out of the electric field signal after denoising and field signal is processed, determine the communication distance between measuring distance of target.

Described in the embodiment of the present invention based on received signal strength (Received Signal Strength, the distance-finding method of adaptive time delay stimation RSS), by the intensity of the electric field signal after stress release treatment and field signal, electromagnetic field time delay estimated value is carried out according to a preliminary estimate, and according to electromagnetic field time delay estimated value determination electromagnetic field time delay initial value according to a preliminary estimate, again the carrying out of the electric field signal after denoising and field signal is processed, thus determine the communication distance between measuring distance of target.Like this, according to electromagnetic field time delay estimated value determination electromagnetic field time delay initial value according to a preliminary estimate, in certain SNR ranges, the impact that cost function local optimum is estimated electromagnetic field time delay can be avoided, and when measuring distance of target is when moving fast, the present invention can constantly update the electromagnetic field time delay initial value of adaptive time delay estimation algorithm according to the intensity of the electric field signal got and field signal, effectively can improve the speed of convergence of adaptive time delay estimation algorithm, electromagnetic field Time delay Estimation Accuracy and distance accuracy.

In the embodiment of the present invention, Received signal strength comprises: electric field signal and field signal.

In the embodiment of the distance-finding method of the aforementioned adaptive time delay stimation based on received signal strength, alternatively, comprise before described S1:

Electromagnetic field time delay initial value is set electromagnetic field time delay difference DELTA _d, number of samples N, the peak-to-average power ratio R transmitted _tX;

Described S1 comprises:

By transmitting terminal, low frequency signal is launched;

Obtain the electric field signal in transmitting by electric field reception antenna and obtain the field signal in transmitting by magnetic field receiving antenna;

The noise in described electric field signal and field signal is eliminated by adaptive threshold noise blanking device;

Electric field signal after stress release treatment and field signal are stored in N number of storage space respectively.

In the embodiment of the present invention, the communication distance between measuring distance of target can be determined according to the time delay of the signal intensity that receives or electromagnetic field respectively.But in complex environment, due to reasons such as buildings block, the decay of Received signal strength is not only relevant to communication distance, simultaneously when receiving end signal to noise ratio (S/N ratio) is lower, received signal strength calculates and has error, and the distance-finding method therefore based on received signal strength is accurate not, but, low frequency signal can penetrate buildings better, when non line of sight and signal to noise ratio (S/N ratio) lower also effectively can extract Delay, therefore be more applicable to indoor range finding.

In the embodiment of the present invention, such as, by the emitting antenna of transmitting terminal, low frequency signal can be launched, recycling receiving antenna receives the electric field signal in transmitting and field signal, after receiving electric field signal and field signal, also need the number of samples N arranging receiver 211 for sampling to electric field signal and field signal, the electric field signal after sampling and field signal carry out self-adaptive processing by adaptive time delay stimation module 213.Shown in Fig. 2, the emitting antenna of transmitting terminal can be electric field antenna, and low frequency signal 203 is launched by electric field antenna 202 by the transmitter 201 of transmitting terminal, low frequency signal frequency-adjustable herein, modulation system is optional, and emissive power is adjustable, and described low frequency signal is low frequency and narrow bandwidth signal.Distance between the receiver 211 of receiving end and transmitter 201 is r204, and receiving antenna comprises: magnetic field receiving antenna 205 and electric field reception antenna 206, receives the field signal in transmitting and electric field signal respectively.In order to the impact of noise decrease intensity to received signal, the field signal received and electric field signal respectively by AGC filter module 208, AGC filter module 207 filtering noise, AGC enlargement factor is adjustable herein, wave filter is according to the Feature Selection that transmits, through AGC filter module conditioning after field signal and electric field signal sample respectively by AD sampling thief 210, AD sampling thief 209, sample frequency according to signal frequency, distance accuracy require adjustable.In the embodiment of the present invention, emitting antenna can be various electric field antenna, and receiving antenna can be various electric field reception antenna and magnetic field receiving antenna, such as, electric field antenna, electric field reception antenna can adopt monopole antenna, and magnetic field antenna, magnetic field receiving antenna can adopt tours antenna.

In the embodiment of the present invention, in order to reduce in S2 computational load when calculating RSS value, the electric field signal after sampling in S1 and field signal are stored in N number of storage space, respectively again to utilize in S2.

In the embodiment of the distance-finding method of the aforementioned adaptive time delay stimation based on received signal strength, alternatively, the described noise eliminated in described electric field signal and field signal by adaptive threshold noise blanking device is comprised:

Determine the intensity of electric field signal and the field signal obtained;

According to the electric field signal determined and the intensity of field signal and the peak-to-average power ratio R transmitted of setting _tX, determine the threshold value B of adaptive threshold noise blanking device:

$B=\sqrt{{\left(\frac{R_{TX}}{10}\right)}^{10}E\left(\right|s\left(k\right){|}^2)}$

Wherein, E (| s (k) | ²) represent received signal strength, the signal that s (k) receives for receiving end, described signal comprises: electric field signal and field signal, contains noise in described electric field signal and field signal, and N is number of samples, and the span of k is 1,2 ..., N.

In the embodiment of the present invention, represent received signal strength RSS by the average power formula (1) of Received signal strength:

$RSS=E\left(\right|s\left(k\right){|}^2)=\frac{sum\left(\right|s\left(k\right){|}^2)}{N}$ Formula (1)

In formula (1), the signal that s (k) receives for receiving end, comprises electric field signal, field signal and noise in s (k), N is number of samples, and the span of k is 1,2 ..., N.Therefore, during by RSS primary Calculation electromagnetic field time delay estimated value, the error of calculation is derived from RSS value and comprises electric field signal intensity, field signal intensity and noise intensity simultaneously.In order to make electromagnetic field time delay evaluated error as far as possible little, must when calculating RSS value, remove the impact of noise as far as possible, exceeded the noise of threshold value in the present invention by adaptive threshold noise blanking device filtering amplitude, Received signal strength s ' (k) after filtering noise is expressed as formula (2):

$s^{\′}\left(k\right)=\left\{\begin{array}{cc}s\left(k\right)& \left|s\left(k\right)\right|\≤B\\ 0& \left|s\left(k\right)\right|>B\end{array}\right.$ Formula (2)

In formula (2), B is the threshold value of adaptive threshold noise blanking device, and when threshold value B arranges too small, most echo signal (echo signal comprises: electric field signal, field signal) by filtering, can increase the error of calculation of RSS value; When threshold value B arranges excessive, to the blanking limited use of noise.In indoor range finding environment, can change along with the movement of measuring distance of target, therefore threshold value B needs Strength Changes according to receiving end echo signal and adaptively changing, when the threshold value B of adaptive noise blanking interval equals the peak value of echo signal, blanking best results.

In the embodiment of the present invention, the peak value of echo signal can pass through peak-to-average power ratio (Peak-to-Average Power Ratio, PAPR) and calculate.Peak-to-average power ratio is defined as formula (3):

$PAPR=10{\log }_{10}\left(\frac{max|s\left(k\right){|}^2}{E\left(\right|s\left(k\right){|}^2)}\right)$ Formula (3)

In the embodiment of the present invention, suppose that the peak-to-average power ratio of transmitting terminal echo signal is R _tX, receiving end is s (k) containing noisy signal, then the threshold value B of adaptive noise blanking interval can represent with formula (4):

$B=\sqrt{{\left(\frac{R_{TX}}{10}\right)}^{10}E\left(\right|s\left(k\right){|}^2)}$ Formula (4)

In the embodiment of the distance-finding method of the aforementioned adaptive time delay stimation based on received signal strength, alternatively, described S2 comprises:

According to the electric field signal stored and field signal, determine the intensity of the electric field signal after stress release treatment and field signal;

According to the propagation formula of low frequency signal, by the intensity of the electric field signal after the stress release treatment determined and field signal, tentatively determine the communication distance between measuring distance of target;

According to the communication distance between measuring distance of target and the relation between electromagnetic field time delay, tentatively determine electromagnetic field time delay estimated value

In the embodiment of the present invention, according to the received signal strength RSS after the sampling stored, and low frequency signal propagation model, communication distance between electromagnetic field time delay and measuring distance of target relation, tentatively determine the communication distance between measuring distance of target and electromagnetic field time delay estimated value wherein, electromagnetic field time delay Δ _tand the relation of the communication distance r between measuring distance of target is expressed as formula (5):

$r=\frac{\mathrm{\λ}}{2\mathrm{\π}}\sqrt[3]{\cot \left({\mathrm{\ω\Δ}}_t\right)}$ Formula (5)

In formula (5), ω is the center angular frequency transmitted, and λ is the wavelength transmitted.

In the embodiment of the present invention, referring to the relation of communication distance between the electromagnetic field time delay that Figure 3 shows that between electric field signal and field signal and measuring distance of target, the relation between path loss and communication distance, wherein, T is the maximum delay between electric field signal and field signal, λ is signal wavelength, and communication distance is (0-0.6) λ.

In the embodiment of the present invention, the electromagnetic intensity transmitted decays along with the increase of communication distance, when respectively with electric field receiving antenna and magnetic field receiving antenna receive transmit time, the propagation formula of low frequency signal is expressed as formula (6), formula (7):

$\frac{P_{RX}}{P_{TX}}{|}_{like}=\frac{k^4}{4{\mathrm{\π}}^2}{A}_{RX}{A}_{TX}(\frac{1}{{\left(kr\right)}^2}-\frac{1}{{\left(kr\right)}^4}+\frac{1}{{\left(kr\right)}^6})$ Formula (6)

$\frac{P_{RX}}{P_{TX}}{|}_{ulike}=\frac{k^4}{4{\mathrm{\π}}^2}{A}_{RX}{L}_{\mathrm{TX}}(\frac{1}{{\left(kr\right)}^2}+\frac{1}{{\left(kr\right)}^4})$ Formula (7)

In formula (6), " like " represents that emitting antenna and receiving antenna are electric field antenna or magnetic field antenna; In formula (7), " ulike " to represent in emitting antenna and receiving antenna that one for electric field antenna, and one is magnetic field antenna, P _tXthe power input of emitting antenna, P _rXthe output power of receiving antenna, A _tXthe useful area of emitting antenna, A _rXthe useful area of receiving antenna, _rbe the communication distance between measuring distance of target, k=2 π/λ is wave number, and λ is the wavelength that transmits.

In the embodiment of the distance-finding method of the aforementioned adaptive time delay stimation based on received signal strength, alternatively, described S3 comprises:

When time, upgrade the electromagnetic field time delay initial value of adaptive time delay stimation module when do not upgrade the electromagnetic field time delay initial value of adaptive time delay stimation module

According to the electromagnetic field time delay initial value determined and utilize adaptive time delay stimation module to process the electric field signal after stress release treatment and field signal, determine that electromagnetic field time delay estimates final value and upgrade electromagnetic field time delay initial value

If electromagnetic field time delay estimates final value for when definite value or error are in preset range, then estimate final value according to described electromagnetic field time delay determine the communication distance between measuring distance of target;

If electromagnetic field time delay estimates final value be in when constantly changing, then return step S1 and continue to perform.

In the embodiment of the present invention, shown in Fig. 2, the digital signal 212 after sampling is by obtaining the electromagnetic field time delay Δ between field signal and electric field signal based on the adaptive time delay stimation module 213 of received signal strength _t214, then obtain the communication distance r215 between measuring distance of target according to the communication distance between measuring distance of target and the relation between electromagnetic field time delay, wherein, based on the structural representation of the adaptive time delay stimation module of received signal strength for shown in Fig. 4.

In the embodiment of the present invention, first arrange based on the electromagnetic field time delay initial value in the adaptive time delay stimation module 213 of received signal strength electromagnetic field time delay difference DELTA _d, wherein, electromagnetic field time delay difference DELTA _daccording to electromagnetic field time delay estimated value error range determine.When time, upgrade the electromagnetic field time delay initial value of adaptive time delay stimation module when do not upgrade the electromagnetic field time delay initial value of adaptive time delay stimation module according to the electromagnetic field time delay initial value determined and utilize adaptive time delay stimation module to process the electric field signal after stress release treatment and field signal, determine that electromagnetic field time delay estimates final value and upgrade electromagnetic field time delay initial value if electromagnetic field time delay estimates final value for when definite value or error are in preset range, then estimate final value according to described electromagnetic field time delay determine the communication distance between measuring distance of target.

In the embodiment of the present invention, if electromagnetic field time delay estimates final value be in when constantly changing, then return step S1 to continue to perform, thus accurate tracking range finding can be realized to the measuring distance of target of movement fast, when measuring distance of target is when moving fast, the present invention can constantly update the initial delay estimated value of adaptive time delay estimation algorithm according to the RSS value of change.When signal to noise ratio (S/N ratio) is in certain scope, the error of the electromagnetic field time delay value calculated according to RSS and true electromagnetic field time delay within the specific limits, effectively can improve the speed of convergence of adaptive time delay estimation algorithm.Simultaneously, due to error within the specific limits, electromagnetic field time delay initial value also can more close to true time delay, effectively can avoid the impact that the local optimum of cost function is estimated time delay, adaptive time delay estimation algorithm is made finally to converge on true time delay, thus the actual communication distance obtained between measuring distance of target, thus improve distance accuracy.

In the embodiment of the present invention, the relation for the communication distance between the relation between the communication distance between RSS value and measuring distance of target and measuring distance of target and electromagnetic field time delay sets up look-up table, can save computing time, improves range finding speed.

The adaptive delay algorithm for estimating based on received signal strength that the embodiment of the present invention provides is applicable to various adaptive time delay estimation algorithm.Referring to the structural representation that Figure 5 shows that basic adaptive time delay stimation module, in actual applications, adaptive time delay stimation module can for different noise circumstances, different signal to noise ratio (S/N ratio)s adopts based on lowest mean square (Least Mean Square, LMS)/least mean p-norm (Least Mean P-norm, the adaptive time delay estimation algorithm of distinct methods and derivative algorithm thereof such as LMP), as lowest mean square time delay estimadon (Least Mean Square Time Delay Estimator, LMSTDE), binding hours delay estimation (Constrained Time Delay Estimator, CTDE), specify time delay estimadon (Explicit Time Delay Estimator, ETDE), simple clear and definite time delay estimadon (Simplified Explicit Time Delay Estimator, SETDE), specify time lag and gain estimation (Explicit Time Delay and Gain Estimator, the adaptive time delay estimation algorithm such as ETDGE).

In the embodiment of the present invention, referring to Figure 6 shows that the adaptive time delay stimation module based on received signal strength provided by the invention is to the optimum results of SETDE algorithm, as can be seen from Figure 6 electromagnetic field time delay step D _sstep=2.5T _sand when changing according to sinusoidal manner, wherein, T _sit is the time interval between sampled point, tradition SETDE algorithm cannot follow the tracks of Delay Variation, after improvement based on received signal strength indicator (Received Signal Strength Indication, RSSI)-SETDE algorithm still can follow the tracks of Delay Variation rapidly, thus can realize accurate tracking range finding to the measuring distance of target of movement fast.

Embodiment two

The present invention also provides a kind of embodiment of range measurement system of the adaptive time delay stimation based on received signal strength, because the range measurement system of the adaptive time delay stimation based on received signal strength provided by the invention is corresponding with the embodiment of the distance-finding method of the aforementioned adaptive time delay stimation based on received signal strength, object of the present invention should can be realized by the process step performed in said method embodiment based on the range measurement system of the adaptive time delay stimation of received signal strength, explanation explanation in the distance-finding method embodiment of the therefore above-mentioned adaptive time delay stimation based on received signal strength, also the embodiment of the range measurement system of the adaptive time delay stimation based on received signal strength provided by the invention is applicable to, to repeat no more in embodiment below the present invention.

The embodiment of the present invention also provides a kind of range measurement system of the adaptive time delay stimation based on received signal strength, comprising:

Stress release treatment unit, for obtaining electric field signal and field signal, and eliminates the noise in described electric field signal and field signal;

The preliminary determining unit of time delay, for determining the intensity of the electric field signal after stress release treatment and field signal, and tentatively determines electromagnetic field time delay estimated value;

Communication distance determining unit, for the electromagnetic field time delay estimated value determination electromagnetic field time delay initial value that basis is tentatively determined, and processes the carrying out of the electric field signal after denoising and field signal, determines the communication distance between measuring distance of target.

The range measurement system of the adaptive time delay stimation based on received signal strength described in the embodiment of the present invention, by the intensity of the electric field signal after stress release treatment and field signal, electromagnetic field time delay estimated value is carried out according to a preliminary estimate, and according to electromagnetic field time delay estimated value determination electromagnetic field time delay initial value according to a preliminary estimate, again the carrying out of the electric field signal after denoising and field signal is processed, thus determine the communication distance between measuring distance of target.Like this, according to electromagnetic field time delay estimated value determination electromagnetic field time delay initial value according to a preliminary estimate, in certain SNR ranges, the impact that cost function local optimum is estimated electromagnetic field time delay can be avoided, and when measuring distance of target is when moving fast, the present invention can constantly update the electromagnetic field time delay initial value of adaptive time delay estimation algorithm according to the intensity of the electric field signal got and field signal, effectively can improve the speed of convergence of adaptive time delay estimation algorithm, electromagnetic field Time delay Estimation Accuracy and distance accuracy.

In the embodiment of the range measurement system of the aforementioned adaptive time delay stimation based on received signal strength, alternatively, described system also comprises:

Initialization unit, for arranging electromagnetic field time delay initial value electromagnetic field time delay difference DELTA _d, number of samples N, the peak-to-average power ratio R transmitted _tX;

Described stress release treatment unit comprises:

Signal emission module, for launching low frequency signal by transmitting terminal;

Electric field signal receiver module, for obtaining the electric field signal in transmitting by electric field reception antenna;

Field signal receiver module, for obtaining the field signal in transmitting by magnetic field receiving antenna;

Stress release treatment module, for eliminating the noise in described electric field signal and field signal by adaptive threshold noise blanking device;

Signal storage module, for being stored to the electric field signal after stress release treatment and field signal respectively in N number of storage space.

In the embodiment of the range measurement system of the aforementioned adaptive time delay stimation based on received signal strength, alternatively, described stress release treatment module comprises:

Received signal strength determination submodule, for determining the intensity of electric field signal and the field signal obtained;

Blanking interval threshold value determination submodule, for according to the intensity of the electric field signal determined and field signal and the peak-to-average power ratio R transmitted of setting _tX, determine the threshold value B of adaptive threshold noise blanking device:

$B=\sqrt{{\left(\frac{R_{TX}}{10}\right)}^{10}E\left(\right|s\left(k\right){|}^2)}$

Wherein, E (| s (k) | ²) represent received signal strength, the signal that s (k) receives for receiving end, described signal comprises: electric field signal and field signal, contains noise in described electric field signal and field signal, and N is number of samples, and the span of k is 1,2 ..., N.

In the embodiment of the range measurement system of the aforementioned adaptive time delay stimation based on received signal strength, alternatively, the preliminary determining unit of described time delay comprises:

Received signal strength determination module, for according to the electric field signal stored and field signal, determines the intensity of the electric field signal after stress release treatment and field signal;

The preliminary determination module of communication distance, for the propagation formula according to low frequency signal, by the intensity of the electric field signal after the stress release treatment determined and field signal, tentatively determines the communication distance between measuring distance of target;

The preliminary determination module of time delay, for according to the communication distance between measuring distance of target and the relation between electromagnetic field time delay, tentatively determines electromagnetic field time delay estimated value

In the embodiment of the range measurement system of the aforementioned adaptive time delay stimation based on received signal strength, alternatively, described communication distance determining unit comprises:

Time delay initial value determination module, for working as time, upgrade the electromagnetic field time delay initial value of adaptive time delay stimation module when do not upgrade the electromagnetic field time delay initial value of adaptive time delay stimation module

Time delay final value determination module, for according to the electromagnetic field time delay initial value determined and utilize adaptive time delay stimation module to process the electric field signal after stress release treatment and field signal, determine that electromagnetic field time delay estimates final value and upgrade electromagnetic field time delay initial value

Communication distance determination module, if estimate final value for electromagnetic field time delay for when definite value or error are in preset range, then estimate final value according to described electromagnetic field time delay determine the communication distance between measuring distance of target;

Return execution module, if estimate final value for electromagnetic field time delay be in when constantly changing, then return step S1 and continue to perform.

The above is the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the prerequisite not departing from principle of the present invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims (10)

1. based on a distance-finding method for the adaptive time delay stimation of received signal strength, it is characterized in that, comprising:

S1: obtain electric field signal and field signal, and eliminate the noise in described electric field signal and field signal;

S2: the intensity determining the electric field signal after stress release treatment and field signal, and tentatively determine electromagnetic field time delay estimated value;

S3: according to the electromagnetic field time delay estimated value determination electromagnetic field time delay initial value tentatively determined, and the carrying out of the electric field signal after denoising and field signal is processed, determine the communication distance between measuring distance of target.

2. method according to claim 1, is characterized in that, comprises before described S1:

Electromagnetic field time delay initial value is set electromagnetic field time delay difference △ _d, number of samples N, the peak-to-average power ratio R transmitted _tX;

Described S1 comprises:

By transmitting terminal, low frequency signal is launched;

Obtain the electric field signal in transmitting by electric field reception antenna and obtain the field signal in transmitting by magnetic field receiving antenna;

The noise in described electric field signal and field signal is eliminated by adaptive threshold noise blanking device;

Electric field signal after stress release treatment and field signal are stored in N number of storage space respectively.

3. method according to claim 2, is characterized in that, the described noise eliminated in described electric field signal and field signal by adaptive threshold noise blanking device is comprised:

Determine the intensity of electric field signal and the field signal obtained;

According to the electric field signal determined and the intensity of field signal and the peak-to-average power ratio R transmitted of setting _tX, determine the threshold value B of adaptive threshold noise blanking device:

$B=\sqrt{{\left(\frac{R_{TX}}{10}\right)}^{10}E\left({\left|s\left(k\right)\right|}^2\right)}$

Wherein, E (| s (k) | ²) represent received signal strength, the signal that s (k) receives for receiving end, described signal comprises: electric field signal and field signal, contains noise in described electric field signal and field signal, and N is number of samples, and the span of k is 1,2 ..., N.

4. method according to claim 3, is characterized in that, described S2 comprises:

According to the electric field signal stored and field signal, determine the intensity of the electric field signal after stress release treatment and field signal;

According to the propagation formula of low frequency signal, by the intensity of the electric field signal after the stress release treatment determined and field signal, tentatively determine the communication distance between measuring distance of target;

According to the communication distance between measuring distance of target and the relation between electromagnetic field time delay, tentatively determine electromagnetic field time delay estimated value

5. method according to claim 4, is characterized in that, described S3 comprises:

When time, upgrade the electromagnetic field time delay initial value of adaptive time delay stimation module when do not upgrade the electromagnetic field time delay initial value of adaptive time delay stimation module

According to the electromagnetic field time delay initial value determined and utilize adaptive time delay stimation module to process the electric field signal after stress release treatment and field signal, determine that electromagnetic field time delay estimates final value and upgrade electromagnetic field time delay initial value

If electromagnetic field time delay estimates final value for when definite value or error are in preset range, then estimate final value according to described electromagnetic field time delay determine the communication distance between measuring distance of target;

If electromagnetic field time delay estimates final value be in when constantly changing, then return step S1 and continue to perform.

6. based on a range measurement system for the adaptive time delay stimation of received signal strength, it is characterized in that, comprising:

Stress release treatment unit, for obtaining electric field signal and field signal, and eliminates the noise in described electric field signal and field signal;

The preliminary determining unit of time delay, for determining the intensity of the electric field signal after stress release treatment and field signal, and tentatively determines electromagnetic field time delay estimated value;

Communication distance determining unit, for the electromagnetic field time delay estimated value determination electromagnetic field time delay initial value that basis is tentatively determined, and processes the carrying out of the electric field signal after denoising and field signal, determines the communication distance between measuring distance of target.

7. system according to claim 6, is characterized in that, described system also comprises:

Initialization unit, for arranging electromagnetic field time delay initial value electromagnetic field time delay difference △ _d, number of samples N, the peak-to-average power ratio R transmitted _tX;

Described stress release treatment unit comprises:

Signal emission module, for launching low frequency signal by transmitting terminal;

Electric field signal receiver module, for obtaining the electric field signal in transmitting by electric field reception antenna;

Field signal receiver module, for obtaining the field signal in transmitting by magnetic field receiving antenna;

Stress release treatment module, for eliminating the noise in described electric field signal and field signal by adaptive threshold noise blanking device;

Signal storage module, for being stored to the electric field signal after stress release treatment and field signal respectively in N number of storage space.

8. system according to claim 7, is characterized in that, described stress release treatment module comprises:

Received signal strength determination submodule, for determining the intensity of electric field signal and the field signal obtained;

Blanking interval threshold value determination submodule, for according to the intensity of the electric field signal determined and field signal and the peak-to-average power ratio R transmitted of setting _tX, determine the threshold value B of adaptive threshold noise blanking device:

$B=\sqrt{{\left(\frac{R_{TX}}{10}\right)}^{10}E\left({\left|s\left(k\right)\right|}^2\right)}$

Wherein, E (| s (k) | ²) represent received signal strength, the signal that s (k) receives for receiving end, described signal comprises: electric field signal and field signal, contains noise in described electric field signal and field signal, and N is number of samples, and the span of k is 1,2 ..., N.

9. system according to claim 8, is characterized in that, the preliminary determining unit of described time delay comprises:

Received signal strength determination module, for according to the electric field signal stored and field signal, determines the intensity of the electric field signal after stress release treatment and field signal;

The preliminary determination module of communication distance, for the propagation formula according to low frequency signal, by the intensity of the electric field signal after the stress release treatment determined and field signal, tentatively determines the communication distance between measuring distance of target;

The preliminary determination module of time delay, for according to the communication distance between measuring distance of target and the relation between electromagnetic field time delay, tentatively determines electromagnetic field time delay estimated value

10. system according to claim 9, is characterized in that, described communication distance determining unit comprises:

Time delay initial value determination module, for working as time, upgrade the electromagnetic field time delay initial value of adaptive time delay stimation module when do not upgrade the electromagnetic field time delay initial value of adaptive time delay stimation module

Time delay final value determination module, for according to the electromagnetic field time delay initial value determined and utilize adaptive time delay stimation module to process the electric field signal after stress release treatment and field signal, determine that electromagnetic field time delay estimates final value and upgrade electromagnetic field time delay initial value

Communication distance determination module, if estimate final value for electromagnetic field time delay for when definite value or error are in preset range, then estimate final value according to described electromagnetic field time delay determine the communication distance between measuring distance of target;

Return execution module, if estimate final value for electromagnetic field time delay be in when constantly changing, then return step S1 and continue to perform.