CN114697170A

CN114697170A - Frequency offset incoherent estimation method, device, equipment and storage medium

Info

Publication number: CN114697170A
Application number: CN202011619628.1A
Authority: CN
Inventors: 王志国
Original assignee: Qianxun Spatial Intelligence Inc
Current assignee: Qianxun Spatial Intelligence Inc
Priority date: 2020-12-30
Filing date: 2020-12-30
Publication date: 2022-07-01

Abstract

The application discloses a frequency offset incoherent estimation method, a device, equipment and a storage medium, wherein coherent accumulation is respectively carried out on multiplication results in N preset time periods to obtain N accumulation results, and the accumulation results comprise I components and Q components; performing dot-cross product operation on the I component and the Q component of the adjacent accumulated results according to the time sequence on the N accumulated results to obtain N-1 dot-product operation results and N-1 cross-product operation results; performing incoherent accumulation on the N-1 dot product operation result according to the sign of the dot product operation result to obtain a dot product operation accumulation result; performing incoherent accumulation on the N-1 cross product operation results according to the signs of the dot product operation results to obtain cross product operation accumulation results; and performing arc tangent frequency discrimination according to the dot product operation accumulation result and the cross product operation accumulation result after incoherent accumulation to obtain a frequency deviation incoherent estimation value, so that noise can be prevented from being further amplified in the frequency discrimination process, and the stability and the precision of the frequency deviation estimation result are improved.

Description

Frequency offset incoherent estimation method, device, equipment and storage medium

Technical Field

The present application relates to the field of wireless communication technologies, and in particular, to a frequency offset non-coherent estimation method, apparatus, device, and storage medium.

Background

With the development of wireless communication technology, wireless communication technology is applied in various fields such as radio communication, satellite navigation, radar signal processing, and the like. However, due to doppler effect, different sources of transmitter and receiver, etc., there is a carrier frequency offset phenomenon during wireless communication between the transmitter and the receiver. In order to stably track the carrier frequency, the carrier frequency offset needs to be estimated.

At present, under the conditions that signals are weak and modulation bit information cannot be accurately predicted, information of signal amplitude is lost due to a frequency offset non-coherent estimation mode in the related technology, so that noise in an estimation result of frequency offset is amplified, and stability and precision of the frequency offset estimation result are low.

Disclosure of Invention

An object of the embodiments of the present application is to provide a method, an apparatus, a device, and a storage medium for frequency offset incoherent estimation, which can prevent further amplification of noise during a frequency discrimination process, thereby improving stability and accuracy of a frequency offset estimation result.

In a first aspect, an embodiment of the present application provides a frequency offset non-coherent estimation method, including:

receiving a GNSS carrier signal and converting the GNSS carrier signal into a digital intermediate frequency signal;

multiplying the digital intermediate frequency signal by a local satellite pseudo-random code signal to obtain a multiplication result;

respectively carrying out coherent accumulation on the multiplication results in N preset time periods to obtain N accumulation results, wherein the accumulation results comprise I components and Q components, N is a positive integer and is more than or equal to 3;

performing dot-cross product operation on the I component and the Q component of the adjacent accumulated results according to the time sequence on the N accumulated results to obtain N-1 dot-product operation results and N-1 cross-product operation results;

performing incoherent accumulation on the N-1 dot product operation result according to the sign of the dot product operation result to obtain a dot product operation accumulation result; performing incoherent accumulation on the N-1 cross product operation results according to the signs of the dot product operation results to obtain cross product operation accumulation results;

and performing arc tangent frequency discrimination according to the dot product operation accumulation result and the cross product operation accumulation result after the incoherent accumulation to obtain a frequency offset incoherent estimation value.

In an implementable manner of the first aspect, the predetermined time period is a bit period of the GNSS carrier signal.

In an implementation manner of the first aspect, the non-coherently accumulating the N-1 dot product operation results according to signs of the dot product operation results to obtain the dot product operation accumulation results specifically includes:

when the sign of the dot product operation result is positive, accumulating the dot product operation result; and

when the sign of the dot product operation result is negative, accumulating the dot product operation result after negating the dot product operation result;

performing incoherent accumulation on the N-1 cross product operation results according to the signs of the dot product operation results to obtain cross product operation accumulation results, which specifically comprises the following steps:

when the sign of the dot product operation result is positive, accumulating the cross product operation result; and

and when the sign of the dot product operation result is negative, accumulating after negating the cross product operation result.

In an implementable manner of the first aspect, the method further comprises:

acquiring a carrier-to-noise ratio of a received GNSS carrier signal;

when the carrier-to-noise ratio is larger than a first threshold, setting the number N of segments of N preset time periods to be larger than a second threshold;

and when the carrier-to-noise ratio is smaller than a first threshold, setting the number N of segments of N preset time periods to be smaller than a second threshold.

In a second aspect, an embodiment of the present application provides a frequency offset non-coherent estimation method, including:

performing dot-cross product operation on the I component and the Q component of the adjacent accumulation results according to the time sequence on the N accumulation results to obtain N-1 dot-product operation results and N-1 cross-product operation results;

performing incoherent accumulation on the N-1 cross product operation results according to the signs of the dot product operation results to obtain cross product operation accumulation results;

and performing sinusoidal frequency discrimination according to the cross product operation accumulation result after incoherent accumulation to obtain a frequency offset incoherent estimation value.

In an implementation manner of the second aspect, the non-coherently accumulating the N-1 cross product operation results according to signs of the dot product operation results to obtain cross product operation accumulation results specifically includes:

In an implementable manner of the second aspect, the preset time period is a bit period of the GNSS carrier signal.

In an implementable manner of the second aspect, the method further comprises:

acquiring a carrier-to-noise ratio of a received GNSS carrier signal;

In a third aspect, an embodiment of the present application provides a frequency offset incoherent estimation apparatus, including:

the receiving module is used for receiving the GNSS carrier signal and converting the GNSS carrier signal into a digital intermediate frequency signal;

the calculation module is used for multiplying the digital intermediate frequency signal by the local satellite pseudo-random code signal to obtain a multiplication result;

the calculation module is further used for performing coherent accumulation on the multiplication results in the N preset time periods respectively to obtain N accumulation results, wherein the accumulation results comprise I components and Q components, N is a positive integer and is not less than 3;

the calculation module is also used for carrying out dot cross product operation on the I component and the Q component of the adjacent accumulation results according to the time sequence on the N accumulation results to obtain N-1 dot product operation results and N-1 cross product operation results;

the calculation module is also used for carrying out incoherent accumulation on the N-1 dot product operation result according to the sign of the dot product operation result so as to obtain a dot product operation accumulation result; performing incoherent accumulation on the N-1 cross product operation results according to the signs of the dot product operation results to obtain cross product operation accumulation results;

and the frequency discrimination module is used for performing arc tangent frequency discrimination according to the dot product operation accumulation result and the cross product operation accumulation result after the incoherent accumulation so as to obtain a frequency offset incoherent estimation value.

In an implementable manner of the third aspect, the preset time period is a bit period of the GNSS carrier signal.

In an implementation manner of the third aspect, the calculating module is specifically configured to accumulate the dot product operation result when the sign of the dot product operation result is positive; and when the sign of the dot product operation result is negative, accumulating the dot product operation result after negating the dot product operation result;

the calculation module is specifically used for accumulating the cross product operation result when the sign of the dot product operation result is positive; and when the sign of the dot product operation result is negative, accumulating after negating the cross product operation result.

In an implementable manner of the third aspect, the apparatus further comprises:

the acquisition module is used for acquiring the carrier-to-noise ratio of the received GNSS carrier signal;

the setting module is used for setting the number N of segments of N preset time periods to be larger than a second threshold when the carrier-to-noise ratio is larger than the first threshold;

and the setting module is further used for setting the number N of the segments of the N preset time periods to be smaller than a second threshold when the carrier-to-noise ratio is smaller than the first threshold.

In a fourth aspect, an embodiment of the present application provides a frequency offset incoherent estimation apparatus, including:

the calculation module is used for multiplying the digital intermediate frequency signal and the local satellite pseudo-random code signal to obtain a multiplication result;

the calculation module is also used for carrying out dot-cross product operation on the I component and the Q component of the adjacent accumulation results according to the time sequence on the N accumulation results to obtain N-1 dot product operation results and N-1 cross product operation results;

the calculation module is also used for performing incoherent accumulation on the N-1 cross product operation results according to the signs of the dot product operation results to obtain cross product operation accumulation results;

and the frequency discrimination module is used for performing sinusoidal frequency discrimination according to the cross product operation accumulation result after incoherent accumulation to obtain a frequency deviation incoherent estimation value.

In an implementation manner of the fourth aspect, the non-coherently accumulating the N-1 cross product operation results according to signs of the dot product operation results to obtain cross product operation accumulation results specifically includes:

In an implementable manner of the fourth aspect, the preset time period is a bit period of the GNSS carrier signal.

In an implementable manner of the fourth aspect, the apparatus further comprises:

the setting module is used for setting the number N of segments of N preset time periods to be larger than a second threshold when the carrier-to-noise ratio is larger than a first threshold;

In a fifth aspect, embodiments of the present application provide an electronic device, which includes a processor, a memory, and a program or instructions stored on the memory and executable on the processor, where the program or instructions, when executed by the processor, implement the steps of the method according to the first aspect or the second aspect.

In a sixth aspect, embodiments of the present application provide a readable storage medium on which a program or instructions are stored, which when executed by a processor, implement the steps of the method according to the first or second aspect.

In the embodiment of the application, a multiplication result is obtained by multiplying a digital intermediate frequency signal by a local satellite pseudo-random code signal; respectively carrying out coherent accumulation on the multiplication results in N preset time periods to obtain N accumulation results, wherein the accumulation results comprise I components and Q components, N is a positive integer and is more than or equal to 3; performing dot-cross product operation on the I component and the Q component of the adjacent accumulated results according to the time sequence on the N accumulated results to obtain N-1 dot-product operation results and N-1 cross-product operation results; performing incoherent accumulation on the N-1 dot product operation result according to the sign of the dot product operation result to obtain a dot product operation accumulation result; performing incoherent accumulation on the N-1 cross product operation results according to the signs of the dot product operation results to obtain cross product operation accumulation results; performing arc tangent frequency discrimination according to the dot product operation accumulation result and the cross product operation accumulation result after incoherent accumulation to obtain a frequency offset incoherent estimation value, and thus performing incoherent accumulation on the N-1 dot product operation result according to the sign of the dot product operation result to obtain a dot product operation accumulation result; and performing incoherent accumulation on the N-1 cross product operation results according to the signs of the dot product operation results to obtain cross product operation accumulation results, so that the loss of amplitude information during arc tangent frequency discrimination of any two adjacent IQ values after the dot product operation accumulation results and the cross product operation accumulation results of the two adjacent IQ values are obtained through calculation is avoided, further noise amplification in the frequency discrimination process is avoided, and the stability and the precision of a frequency deviation estimation result are improved.

Drawings

Fig. 1 is a schematic flowchart of a frequency offset non-coherent estimation method according to an embodiment of the present application;

FIG. 2 is a flow chart of another frequency offset non-coherent estimation method according to an embodiment of the present application;

FIG. 3 is a block diagram illustrating an architecture of a GNSS receiver receiving baseband tracking from an antenna for satellite signals according to an embodiment of the present disclosure;

FIG. 4 is a block diagram illustrating an architecture of a single trace channel process according to an embodiment of the present disclosure;

FIG. 5 is a flow chart illustrating a further method for non-coherent estimation of frequency offset according to an embodiment of the present application;

fig. 6 is a schematic structural diagram of a frequency offset incoherent estimation apparatus according to an embodiment of the present application;

fig. 7 is a schematic structural diagram of another frequency offset incoherent estimation apparatus provided in an embodiment of the present application;

fig. 8 is a schematic diagram of a hardware structure of an electronic device according to an embodiment of the present application.

Detailed Description

Features and exemplary embodiments of various aspects of the present application will be described in detail below, and in order to make objects, technical solutions and advantages of the present application more apparent, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are intended to be illustrative only and are not intended to be limiting. It will be apparent to one skilled in the art that the present application may be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present application by illustrating examples thereof.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

At present, in the related art, a dot-cross product operation is performed on two adjacent IQ components, then an inverse tangent frequency discrimination is directly performed on the dot-cross product operation results of the two IQ components, and then frequency discrimination results are accumulated to obtain a frequency offset estimation result. And accumulating the frequency discrimination result to accumulate the noise in the frequency deviation estimation result because the noise of single point cross product operation is large. And under the condition that the modulation bit information cannot be accurately predicted, the unknown signal can send polarity inversion, so that coherent integration time is limited, and under the conditions of long distance (such as satellite communication, deep space communication), shielding, indoor and interference, the received signal is weak, and the signal-to-noise ratio cannot be increased through longer integration time. Therefore, the frequency offset estimation method in the related art also causes information loss of signal amplitude, further increases noise in the frequency offset estimation result, and causes the result stability and accuracy of frequency offset estimation to be low.

In order to solve the technical problem in the related art, embodiments of the present application provide a frequency offset non-coherent estimation method, apparatus, device, and computer storage medium, which can solve the problem that a frequency offset estimation manner in the related art may cause information loss of signal amplitude, thereby causing noise of an estimation result of frequency offset to be amplified, and causing both stability and accuracy of the frequency offset estimation result to be low. First, a frequency offset non-coherent estimation method provided in the embodiment of the present application is described below.

Fig. 1 is a flowchart illustrating a frequency offset non-coherent estimation method 100 according to an embodiment of the present disclosure.

As shown in fig. 1, a frequency offset non-coherent estimation method 100 provided in the embodiment of the present application may include S101 to S106.

S101: and receiving the GNSS carrier signal and converting the GNSS carrier signal into a digital intermediate frequency signal.

The receiver can receive the GNSS carrier signal through the antenna, and perform low noise amplification, frequency mixing, filtering, automatic gain control and other processing on the GNSS carrier signal, and convert the GNSS carrier signal into a digital intermediate frequency signal after performing frequency mixing processing.

S102: and multiplying the digital intermediate frequency signal by a local satellite pseudo-random code signal to obtain a multiplication result.

Because the GNSS carrier signal has pseudo-random code modulation, after the GNSS carrier signal is converted into the digital intermediate frequency signal, the digital intermediate frequency signal also contains pseudo-random code modulation, and in order to remove the pseudo-random code modulation in the GNSS carrier signal, the digital intermediate frequency signal and the local signal pseudo-random code signal need to be multiplied, so that a multiplication result is obtained.

S103: and respectively performing coherent accumulation on the multiplication results in N preset time periods to obtain N accumulation results, wherein the accumulation results comprise I components and Q components, N is a positive integer and is not less than 3.

After the multiplication result is obtained, the multiplication result can be divided into N preset time periods, and then the multiplication results in the preset time periods are respectively subjected to coherent accumulation, so that N accumulation results are obtained. For example, the time corresponding to the multiplication result is 10ms, the multiplication result is divided into 5 time segments, each time segment includes the multiplication result of 2ms, and the multiplication results in each 2ms are coherently accumulated to obtain 5 accumulation results. Each accumulation result includes an I component and a Q component, i.e. the components of the accumulation result in the IQ coordinate system. It should be noted that the N accumulation results have a chronological order. Wherein N is a positive integer and is not less than 3.

In one embodiment, the multiplication result may be divided into the multiplication results for N preset time periods according to the bit period of the GNSS carrier signal. Wherein the preset time period may be a bit period of the GNSS carrier signal.

In one embodiment, to ensure the sensitivity of tracking the GNSS carrier signal, the carrier-to-noise ratio of the GNSS carrier signal may also be obtained, and the number of segments of the preset time period is determined according to the carrier-to-noise ratio. When the carrier-to-noise ratio is greater than a preset first threshold, the number N of segments of the N preset time periods is greater than a preset second threshold, and when the carrier-to-noise ratio is less than the preset first threshold, the number N of segments of the N preset time periods is less than the preset second threshold.

Therefore, the number of segments of the preset time period is determined according to the magnitude of the carrier-to-noise ratio, and the sensitivity and the dynamic capability of tracking the carrier signal of the GNSS can be considered.

S104: and performing dot cross product operation on the I component and the Q component of the adjacent accumulation results according to the time sequence on the N accumulation results to obtain N-1 dot product operation results and N-1 cross product operation results.

And performing dot-cross product operation on the I component and the Q component of two adjacent accumulation results based on the time sequence of each accumulation result so as to obtain an N-1 dot-product operation result and an N-1 cross-product operation result. Here, N-1 dot product operation results and N-1 cross product operation results can be obtained by simultaneously performing dot product operation and cross product operation on two adjacent accumulation results.

Dot product operation result dot of ith accumulation result_iSatisfying the following formula (1):

dot_i＝I_i+1I_i+Q_i+1Q_i (1)

cross product operation result cross of ith accumulation result_iSatisfies the following formula (2):

cross_i＝Q_i+1I_i+I_i+1Q_i (2)

wherein, I_iI component, Q, representing the ith accumulation result_iRepresenting the Q component, I, of the ith accumulation result_i+1I component, Q, representing the I +1 th accumulation result_i+1Representing the Q component of the i +1 th accumulation result.

S105: performing incoherent accumulation on the N-1 dot product operation results according to the signs of the dot product operation results to obtain dot product operation accumulation results; and performing incoherent accumulation on the N-1 cross product operation results according to the signs of the dot product operation results to obtain cross product operation accumulation results.

In an embodiment, in order to avoid low stability and low accuracy of the frequency offset estimation result obtained after frequency discrimination, after the dot product operation result of the ith accumulation result (i.e. the ith dot product operation result) is obtained by calculation, according to the sign of the ith dot product operation result, the ith dot product operation result and the previous i +1 dot product operation result are subjected to incoherent accumulation. After the cross product operation result (i.e. the ith dot product operation result) of the ith accumulation result is obtained through calculation, the ith cross product operation result and the previous i +1 dot product operation result are subjected to incoherent accumulation according to the sign of the ith dot product operation result. Wherein, i is 1, 2, 3, … …, N-1.

Therefore, the inverse tangent frequency discrimination is not needed to be carried out after the point cross product operation is carried out on the single I component and the single Q component, the results of the point cross product operation are subjected to incoherent accumulation, and the noise amplification in the frequency deviation estimation result caused by accumulation of the frequency discrimination result too early is avoided.

In one embodiment, in order to avoid low stability and accuracy of the frequency offset estimation result obtained after frequency discrimination, after the dot product operation results of N-1 accumulation results (i.e., N-1 dot product operation results) are obtained by calculation, according to the sign of each dot product operation result, each dot product operation result is subjected to incoherent accumulation. After the cross product operation results (namely N-1 dot product operation results) of N-1 accumulation results are obtained through calculation, each cross product operation result is subjected to incoherent accumulation according to the sign of each dot product operation result. Wherein, i is 1, 2, 3, … …, N-1.

In one embodiment, to avoid the loss of information about the amplitude of the signal after the arctangent discrimination after the dot-cross product operation is performed on the individual I and Q components, which may increase noise, the arctangent discrimination may be performed based on a maximum likelihood rule. Specifically, based on the maximum likelihood rule, when the GNSS carrier signal is stably tracked, the maximum likelihood condition needs to be satisfied, and then the signs of the N-1 dot product operation results need to be the same. Based on this, S105 may further specifically include the following steps: and when the sign of the dot product operation result is positive, accumulating the dot product operation result. And when the sign of the dot product operation result is negative, negating the sign of the dot product operation result, and accumulating the dot product operation result after the sign is negated. Similarly, when the sign of the dot product operation result is positive, the cross product operation result is accumulated, when the sign of the dot product operation result is negative, the sign of the cross product operation result is inverted, and the cross product operation result after the sign is inverted is accumulated.

Therefore, the non-coherent accumulation is carried out on the dot product operation result and the cross product operation result with the negative dot product operation sign in the non-coherent accumulation process, and the non-coherent accumulation is carried out after the sign is turned over, so that the noise amplification in the frequency offset estimation result caused by accumulation of the frequency discrimination result too early is avoided.

S106: and performing arc tangent frequency discrimination according to the dot product operation accumulation result and the cross product operation accumulation result after the incoherent accumulation to obtain a frequency offset incoherent estimation value.

Performing arc tangent frequency discrimination on the dot product operation accumulation result and the cross product operation accumulation result after the incoherent accumulation to obtain a frequency deviation incoherent estimation value, specifically, the frequency deviation incoherent estimation value

Satisfies the following formula (3)

Wherein crossSum represents the cross product operation result after incoherent accumulation, dotSum represents the dot product operation result after incoherent accumulation, and T_cRepresenting time.

The above-described S104-S106 are described in detail below by way of specific example embodiments,

the N accumulation results can be expressed as { (I)₁，Q₁)，(I₂，Q₂)，……(I_N，Q_N)}。

As shown in fig. 2, S201: obtaining an accumulated result { (I)₁，Q₁)，(I₂，Q₂)，……(I_N，Q_N)}。

S202: when initializing, i is 1, dotSum is 0, crossSum is 0, wherein i is 1, 2, 3, … …, N-1.

S203: and judging whether i is smaller than N, if so, executing S204, and if not, executing S206.

S204: performing dot product operation (dot) on the ith accumulation result and the (i + 1) th accumulation result_i＝I_i+1I_i+Q_i+1Q_i) Sum-cross product operation (cross)_i＝Q_i+1I_i+I_i+1Q_i) Obtaining the dot product operation result and the cross product operation result, and judging the sign of the dot product operation result

Wherein the content of the first and second substances,

represents a symbol, and is compared with dot_iAre the same.

S205: to the ith dot product operation result

Sum of first i dot product operation results and incoherent accumulation sum (dotSum)_i-1) Adding

And will make i +1, execution continues with S203.

S206: and performing arc tangent frequency discrimination according to the dot product operation accumulation result and the cross product operation accumulation result after the incoherent accumulation to obtain a frequency offset incoherent estimation value.

As another example, the present application further provides a method for a GNSS receiver to receive baseband tracking from an antenna of a satellite signal, where the method for the GNSS receiver to receive baseband tracking from an antenna of a satellite signal may specifically include the following steps 31 to 34.

Step 31: the GNSS carrier signal is first received by the antenna of the receiver 301.

Step 32: the carrier signal received by the antenna is processed by the receiver 301, and the receiver 301 generally includes modules such as low noise amplifier, frequency mixing, filtering, automatic gain control, and the like, and finally outputs an intermediate frequency analog signal.

Step 33: the intermediate frequency analog signal is converted to a digital signal by an analog to digital converter 302 and subsequent processing is performed in the digital domain.

Step 34: in order to facilitate subsequent tracking channel processing, the digital signal output by the analog-to-digital converter 302 needs to be preprocessed by the preprocessor 303, which includes processing procedures of digital mixing, anti-interference, down-sampling, digital filtering, and weighting to a lower bit width, and the like, and is finally output to the parallel tracking channel 304 to simultaneously track multiple satellites.

The embodiment of the present application further provides a processing method for a single tracking channel, as shown in fig. 4, which describes a generation process of a cross-correlation signal, and the cross-correlation signal is output to a post-processing module to perform estimation of a code phase, a carrier frequency, and a carrier phase deviation, and specifically may include steps 41 to 47.

Step 41: in the tracking channel, the signal preprocessed by the preprocessor 303 is first compensated by the digital mixer 401 for local oscillation bias and doppler frequency offset and phase of the tracked satellite. The local oscillator bias is the same for the same type of satellite, and the doppler bias and phase of each satellite are different and related to the relative speed and distance between the satellite and the receiver. The other input of the mixer 401 is a digital carrier signal from a carrier digital oscillator module 402.

Step 42: the carrier digital oscillator module 402 is controlled by the frequency deviation and phase deviation signals output from the pll/pll 403, and outputs a complex exponential signal expected to be the same as the frequency and phase of the received satellite signal to the mixer 401 in step 5.

Step 43: the code digital oscillator module 404 is controlled by a code phase deviation signal output by a delay locked loop 405 to generate a code rate signal and a code phase signal that are expected to be the same as the received tracking satellite signal.

And step 44: based on the code rate signal and the code phase signal output by the code digital oscillator module 404, the code generator module 406 generates a specific pseudo random code signal, i.e., a local pseudo random code discrete signal, for the tracked satellite.

Step 45: the local pseudo random code signal generated by the code generator module 406 is output to the code memory 407, and the length of the code memory 407 is the same as the number of the parallel correlators 408, and corresponds to one another.

Step 46: each correlator 408 first multiplies the pseudo random code signal stored in a unit of the corresponding code memory 407 by the frequency offset and phase offset removed signal output in the previous step 9 to release the pseudo random code modulation of the received signal.

Step 47: accumulating the signals which are output in the step 10 and have the offset frequency, the carrier phase deviation and the pseudo-random code modulation removed, outputting the accumulated result to the post-processing module 409 at intervals of a preset time, and simultaneously resetting to start the next accumulation. The plurality of correlators 408 perform parallel processing and perform accumulation, output, and clear operations simultaneously, and the parallel correlators 408 are spaced in time the same as the sampling spacing of the local pseudorandom code signal.

According to the frequency offset non-coherent estimation method provided by the embodiment of the application, a multiplication result is obtained by multiplying a digital intermediate frequency signal and a local satellite pseudo-random code signal; respectively carrying out coherent accumulation on the multiplication results in N preset time periods to obtain N accumulation results, wherein the accumulation results comprise I components and Q components, N is a positive integer and is more than or equal to 3; performing dot-cross product operation on the I component and the Q component of the adjacent accumulated results according to the time sequence on the N accumulated results to obtain N-1 dot-product operation results and N-1 cross-product operation results; performing incoherent accumulation on the N-1 dot product operation result according to the sign of the dot product operation result to obtain a dot product operation accumulation result; performing incoherent accumulation on the N-1 cross product operation results according to the signs of the dot product operation results to obtain cross product operation accumulation results; performing arc tangent frequency discrimination according to the dot product operation accumulation result and the cross product operation accumulation result after incoherent accumulation to obtain a frequency offset incoherent estimation value, and thus performing incoherent accumulation on the N-1 dot product operation result according to the sign of the dot product operation result to obtain a dot product operation accumulation result; and performing incoherent accumulation on the N-1 cross product operation results according to the signs of the dot product operation results to obtain cross product operation accumulation results, so that the loss of amplitude information during arc tangent frequency discrimination of any two adjacent IQ values after the dot product operation accumulation results and the cross product operation accumulation results of the two adjacent IQ values are obtained through calculation is avoided, further noise amplification in the frequency discrimination process is avoided, and the stability and the precision of a frequency deviation estimation result are improved.

The embodiment of the application also provides another frequency offset non-coherent estimation method.

Fig. 5 is a flowchart illustrating a method 500 for non-coherent frequency offset estimation according to an embodiment of the present application.

As shown in fig. 5, a frequency offset non-coherent estimation method 500 provided by the embodiment of the present application may include S501-S506.

S501: and receiving the GNSS carrier signal and converting the GNSS carrier signal into a digital intermediate frequency signal.

S502: and multiplying the digital intermediate frequency signal by the local satellite pseudo-random code signal to obtain a multiplication result.

S503: and respectively carrying out coherent accumulation on the multiplication results in N preset time periods to obtain N accumulation results, wherein the accumulation results comprise I components and Q components, N is a positive integer and is more than or equal to 3.

S504: and performing point cross product operation on the I component and the Q component of the adjacent accumulated results according to the time sequence on the N accumulated results to obtain N-1 point product operation results and N-1 cross product operation results.

It should be noted that S501 is the same as S101, S502 is the same as S102, S503 is the same as S103, and S504 is the same as S104, and for the sake of brevity, the detailed description of S501 to S5,4 refers to the detailed description of S101 to S104, and only the differences will be described in detail here.

S505: and performing incoherent accumulation on the N-1 cross product operation results according to the signs of the dot product operation results to obtain cross product operation accumulation results.

Therefore, the inverse tangent frequency discrimination is not needed to be carried out after the point cross product operation is carried out on the single I component and the Q component, the result of the point cross product operation is subjected to incoherent accumulation, and noise amplification in the frequency offset estimation result caused by accumulation of the frequency discrimination result too early is avoided.

In one embodiment, in order to avoid low stability and accuracy of the frequency offset estimation result obtained after frequency discrimination, after cross product operation results of N-1 accumulation results (i.e., N-1 dot product operation results) are obtained by calculation, each cross product operation result is subjected to incoherent accumulation according to a symbol of each dot product operation result. Wherein, i is 1, 2, 3, … …, N-1.

Therefore, the inverse tangent frequency discrimination is not needed to be carried out after the cross product operation is carried out on the single I component and the single Q component, the results of the cross product operation are subjected to incoherent accumulation, and the noise amplification in the frequency deviation estimation result caused by accumulation of the frequency discrimination result too early is avoided.

In one embodiment, to avoid loss of information about the amplitude of the signal after the inverse tangent discrimination after the cross product operation on the individual I and Q components, which may increase noise, the inverse tangent discrimination may be performed based on a maximum likelihood rule. Specifically, based on the maximum likelihood rule, when the GNSS carrier signal is stably tracked, the maximum likelihood condition needs to be satisfied, and then the signs of the N-1 dot product operation results need to be the same. Based on this, S505 may further specifically include the following steps: when the sign of the dot product operation result is positive, the cross product operation result is accumulated, when the sign of the dot product operation result is negative, the sign of the cross product operation result is inverted, and the cross product operation result after the sign is inverted is accumulated.

Therefore, the inverse tangent frequency discrimination is not needed to be carried out after the cross product operation is carried out on the single I component and the single Q component, the results of the cross product operation are subjected to incoherent accumulation, in the incoherent accumulation process, the sign is required to be turned over and then subjected to incoherent accumulation aiming at the dot product operation result with the negative sign, and the noise amplification in the frequency deviation estimation result caused by accumulation of the frequency discrimination result too early is avoided.

S506: and performing sinusoidal frequency discrimination according to the cross product operation accumulation result after incoherent accumulation to obtain a frequency offset incoherent estimation value.

Performing sinusoidal frequency discrimination on the cross product operation accumulation result after incoherent accumulation to obtain a frequency deviation incoherent estimation value, specifically, a frequency deviation incoherent estimation value

Satisfies the following formula (5):

In one embodiment, in order to ensure the sensitivity of tracking the GNSS carrier signal, the carrier-to-noise ratio of the GNSS carrier signal may also be obtained, and the number of segments of the preset time period is determined according to the carrier-to-noise ratio. When the carrier-to-noise ratio is greater than a preset first threshold, the number N of segments of the N preset time periods is greater than a preset second threshold, and when the carrier-to-noise ratio is less than the preset first threshold, the number N of segments of the N preset time periods is less than the preset second threshold.

Therefore, the number of segments of the preset time period is determined according to the magnitude of the carrier-to-noise ratio, and the sensitivity of tracking the carrier signal of the GNSS can be ensured.

According to the frequency offset non-coherent estimation method provided by the embodiment of the application, a multiplication result is obtained by multiplying a digital intermediate frequency signal and a local satellite pseudo-random code signal; respectively carrying out coherent accumulation on the multiplication results in N preset time periods to obtain N accumulation results, wherein the accumulation results comprise I components and Q components, N is a positive integer and is more than or equal to 3; performing cross product operation on the I component and the Q component of the adjacent accumulated results according to the time sequence on the N accumulated results to obtain N-1 cross product operation results; performing incoherent accumulation on the N-1 cross product operation results according to the signs of the dot product operation results to obtain cross product operation accumulation results; and performing arc tangent frequency discrimination according to the dot product operation accumulation result and the cross product operation accumulation result after incoherent accumulation to obtain a frequency deviation incoherent estimation value, thus performing incoherent accumulation on the N-1 cross product operation results according to the sign of the dot product operation result to obtain a cross product operation accumulation result, avoiding the loss of amplitude information when performing arc tangent frequency discrimination on any two adjacent IQ values after calculating the cross product operation accumulation result of the two adjacent IQ values, further avoiding the further amplification of noise in the frequency discrimination process, and further improving the stability and the precision of the frequency deviation estimation result.

Based on the frequency offset incoherent estimation method provided in the embodiment of fig. 1 of the present application, accordingly, the present application provides a frequency offset incoherent estimation apparatus of an embodiment. The frequency offset non-coherent estimation apparatus provided in the embodiment of the present application is described in detail below.

Fig. 6 is a schematic structural diagram of a frequency offset non-coherent estimation apparatus 600 according to the present application.

As shown in fig. 6, the apparatus 600 for non-coherent estimation of frequency offset provided by the present application may include: a receiving module 601, a calculating module 602 and a frequency discriminating module 603.

A receiving module 601, configured to receive a GNSS carrier signal and convert the GNSS carrier signal into a digital intermediate frequency signal;

a calculating module 602, configured to multiply the digital intermediate frequency signal with a local satellite pseudorandom code signal to obtain a multiplication result;

the calculating module 602 is further configured to perform coherent accumulation on the multiplication results within N preset time periods to obtain N accumulation results, where the accumulation results include an I component and a Q component, where N is a positive integer and is greater than or equal to 3;

the calculating module 602 is further configured to perform a cross product operation on the I component and the Q component of the adjacent accumulated results according to the time sequence for the N accumulated results to obtain N-1 dot product operation results and N-1 cross product operation results;

the calculating module 602 is further configured to perform incoherent accumulation on the N-1 dot product operation result according to a sign of the dot product operation result to obtain a dot product operation accumulation result; performing incoherent accumulation on the N-1 cross product operation results according to the signs of the dot product operation results to obtain cross product operation accumulation results;

the frequency discrimination module 603 is configured to perform arc tangent frequency discrimination according to the dot product operation accumulation result and the cross product operation accumulation result after the incoherent accumulation to obtain a frequency offset incoherent estimation value.

In one embodiment of the present application, the predetermined time period is a bit period of the GNSS carrier signal.

In an embodiment of the present application, the calculating module 602 is specifically configured to accumulate the dot product operation result when the sign of the dot product operation result is positive; and when the sign of the dot product operation result is negative, accumulating the dot product operation result after negating the dot product operation result;

the calculating module 602 is further configured to accumulate the cross product operation result when the sign of the dot product operation result is positive; and when the sign of the dot product operation result is negative, accumulating after negating the cross product operation result.

In one embodiment of the present application, the apparatus 600 further comprises:

Each module/unit in the apparatus shown in fig. 6 has a function of implementing each step in fig. 1, and can achieve the corresponding technical effect, and for brevity, the description is not repeated here.

According to the frequency offset non-coherent estimation device provided by the embodiment of the application, a multiplication result is obtained by multiplying a digital intermediate frequency signal and a local satellite pseudo-random code signal; respectively carrying out coherent accumulation on the multiplication results in N preset time periods to obtain N accumulation results, wherein the accumulation results comprise I components and Q components, N is a positive integer and is more than or equal to 3; performing dot-cross product operation on the I component and the Q component of the adjacent accumulated results according to the time sequence on the N accumulated results to obtain N-1 dot-product operation results and N-1 cross-product operation results; performing incoherent accumulation on the N-1 dot product operation result according to the sign of the dot product operation result to obtain a dot product operation accumulation result; performing incoherent accumulation on the N-1 cross product operation results according to the signs of the dot product operation results to obtain cross product operation accumulation results; performing arc tangent frequency discrimination according to the dot product operation accumulation result and the cross product operation accumulation result after incoherent accumulation to obtain a frequency offset incoherent estimation value, and thus performing incoherent accumulation on the N-1 dot product operation result according to the sign of the dot product operation result to obtain a dot product operation accumulation result; and performing incoherent accumulation on the N-1 cross product operation results according to the signs of the dot product operation results to obtain cross product operation accumulation results, so that the loss of amplitude information during arc tangent frequency discrimination of any two adjacent IQ values after the dot product operation accumulation results and the cross product operation accumulation results of the two adjacent IQ values are obtained through calculation is avoided, further noise amplification in the frequency discrimination process is avoided, and the stability and the precision of a frequency deviation estimation result are improved.

Based on the frequency offset incoherent estimation method provided in the embodiment of fig. 5 in the present application, accordingly, the present application provides a frequency offset incoherent estimation apparatus of an embodiment. The frequency offset non-coherent estimation apparatus provided in the embodiment of the present application is described in detail below.

Fig. 7 is a schematic structural diagram of another frequency offset incoherent estimation apparatus 700 according to an embodiment of the present application.

The embodiment of the present application as shown in fig. 7 provides a frequency offset incoherent estimation apparatus 700, which may include the frequency offset incoherent estimation apparatus 700 provided by the present application, and may include: a receiving module 701, a calculating module 702 and a frequency discriminating module 703.

A receiving module 701, configured to receive a GNSS carrier signal and convert the GNSS carrier signal into a digital intermediate frequency signal;

a calculating module 702, configured to multiply the digital intermediate frequency signal with a local satellite pseudorandom code signal to obtain a multiplication result;

the calculating module 702 is further configured to perform coherent accumulation on the multiplication results within N preset time periods to obtain N accumulation results, where the accumulation results include an I component and a Q component, where N is a positive integer and is greater than or equal to 3;

the calculating module 702 is further configured to perform a cross product operation on the I component and the Q component of the adjacent accumulated results according to the time sequence for the N accumulated results to obtain N-1 dot product operation results and N-1 cross product operation results;

the calculating module 702 is further configured to perform incoherent accumulation on the N-1 cross product operation results according to the sign of the dot product operation result to obtain a cross product operation accumulation result;

the frequency discrimination module 703 is configured to perform sinusoidal frequency discrimination according to the cross product operation accumulation result after the incoherent accumulation to obtain a frequency offset incoherent estimate.

In an embodiment of the present application, performing incoherent accumulation on N-1 cross product operation results according to signs of dot product operation results to obtain cross product operation accumulation results, specifically including:

In one embodiment of the present application, the apparatus 700 further comprises:

Each module/unit in the apparatus shown in fig. 7 has a function of implementing each step in fig. 5, and can achieve corresponding technical effects, and for brevity, no further description is provided here.

According to the frequency offset non-coherent estimation device provided by the embodiment of the application, a multiplication result is obtained by multiplying a digital intermediate frequency signal and a local satellite pseudo-random code signal; respectively carrying out coherent accumulation on the multiplication results in N preset time periods to obtain N accumulation results, wherein the accumulation results comprise I components and Q components, N is a positive integer and is more than or equal to 3; performing cross product operation on the I component and the Q component of the adjacent accumulated results according to the time sequence on the N accumulated results to obtain N-1 cross product operation results; performing incoherent accumulation on the N-1 cross product operation results according to the signs of the dot product operation results to obtain cross product operation accumulation results; and performing arc tangent frequency discrimination according to the dot product operation accumulation result and the cross product operation accumulation result after incoherent accumulation to obtain a frequency deviation incoherent estimation value, thus performing incoherent accumulation on the N-1 cross product operation results according to the sign of the dot product operation result to obtain a cross product operation accumulation result, avoiding the loss of amplitude information when performing arc tangent frequency discrimination on any two adjacent IQ values after calculating the cross product operation accumulation result of the two adjacent IQ values, further avoiding the further amplification of noise in the frequency discrimination process, and further improving the stability and the precision of the frequency deviation estimation result.

Fig. 8 shows a hardware structure diagram of an electronic device provided in an embodiment of the present application.

As shown in fig. 8, the electronic device may include a processor 801 and a memory 802 that stores computer program instructions.

Specifically, the processor 801 may include a Central Processing Unit (CPU), an Application Specific Integrated Circuit (ASIC), or one or more Integrated circuits configured to implement the embodiments of the present Application.

Memory 802 may include mass storage for data or instructions. By way of example, and not limitation, memory 802 may include a Hard Disk Drive (HDD), a floppy Disk Drive, flash memory, an optical Disk, a magneto-optical Disk, a tape, or a Universal Serial Bus (USB) Drive or a combination of two or more of these. In one example, memory 802 can include removable or non-removable (or fixed) media, or memory 802 is non-volatile solid-state memory. The memory 802 may be internal or external to the integrated gateway disaster recovery device.

In one example, the Memory 802 may be a Read Only Memory (ROM). In one example, the ROM may be mask programmed ROM, programmable ROM (prom), erasable prom (eprom), electrically erasable prom (eeprom), electrically rewritable ROM (earom), or flash memory, or a combination of two or more of these.

The memory 802 may include Read Only Memory (ROM), Random Access Memory (RAM), magnetic disk storage media devices, optical storage media devices, flash memory devices, electrical, optical, or other physical/tangible memory storage devices. Thus, in general, the memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., memory devices) encoded with software comprising computer-executable instructions and when the software is executed (e.g., by one or more processors), it is operable to perform operations described with reference to the methods according to an aspect of the present disclosure.

The processor 801 reads and executes the computer program instructions stored in the memory 802 to implement the method/steps in the embodiments shown in fig. 1 and 5, and achieve the corresponding technical effects achieved by the example shown in fig. 1 and 5 executing the method/steps, which are not described herein again for brevity.

In one example, the electronic device can also include a communication interface 803 and a bus 810. As shown in fig. 8, the processor 801, the memory 802, and the communication interface 803 are connected via a bus 810 to complete communication therebetween.

The communication interface 803 is mainly used for implementing communication between modules, apparatuses, units and/or devices in the embodiments of the present application.

The bus 810 includes hardware, software, or both to couple the components of the electronic device to one another. By way of example, and not limitation, a Bus may include an Accelerated Graphics Port (AGP) or other Graphics Bus, an Enhanced Industry Standard Architecture (EISA) Bus, a Front-Side Bus (Front Side Bus, FSB), a Hyper Transport (HT) interconnect, an Industry Standard Architecture (ISA) Bus, an infiniband interconnect, a Low Pin Count (LPC) Bus, a memory Bus, a Micro Channel Architecture (MCA) Bus, a Peripheral Component Interconnect (PCI) Bus, a PCI-Express (PCI-X) Bus, a Serial Advanced Technology Attachment (SATA) Bus, a video electronics standards association local (VLB) Bus, or other suitable Bus or a combination of two or more of these. Bus 810 may include one or more buses, where appropriate. Although specific buses are described and shown in the embodiments of the application, any suitable buses or interconnects are contemplated by the application.

The electronic device may execute the frequency offset incoherent estimation method in the embodiment of the present application based on the currently intercepted spam short messages and the short messages reported by the user, thereby implementing the frequency offset incoherent estimation method described in combination with fig. 1 and 5.

In addition, in combination with the frequency offset non-coherent estimation method in the foregoing embodiments, the embodiments of the present application may provide a computer storage medium to implement. The computer storage medium having computer program instructions stored thereon; the computer program instructions, when executed by a processor, implement any of the frequency offset non-coherent estimation methods in the above embodiments.

It is to be understood that the present application is not limited to the particular arrangements and instrumentality described above and shown in the attached drawings. A detailed description of known methods is omitted herein for the sake of brevity. In the above embodiments, several specific steps are described and shown as examples. However, the method processes of the present application are not limited to the specific steps described and illustrated, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps, after comprehending the spirit of the present application.

The functional blocks shown in the above-described structural block diagrams may be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, it may be, for example, an electronic Circuit, an Application Specific Integrated Circuit (ASIC), suitable firmware, plug-in, function card, or the like. When implemented in software, the elements of the present application are the programs or code segments used to perform the required tasks. The program or code segments may be stored in a machine-readable medium or transmitted by a data signal carried in a carrier wave over a transmission medium or a communication link. A "machine-readable medium" may include any medium that can store or transfer information. Examples of a machine-readable medium include electronic circuits, semiconductor memory devices, ROM, flash memory, Erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, Radio Frequency (RF) links, and so forth. The code segments may be downloaded via computer networks such as the internet, intranet, etc.

It should also be noted that the exemplary embodiments mentioned in this application describe some methods or systems based on a series of steps or devices. However, the present application is not limited to the order of the above-described steps, that is, the steps may be performed in the order mentioned in the embodiments, may be performed in an order different from the order in the embodiments, or may be performed simultaneously.

Aspects of the present disclosure are described above with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the disclosure. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, implement the functions/acts specified in the flowchart and/or block diagram block or blocks. Such a processor may be, but is not limited to, a general purpose processor, a special purpose processor, an application specific processor, or a field programmable logic circuit. It will also be understood that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware for performing the specified functions or acts, or combinations of special purpose hardware and computer instructions.

As described above, only the specific embodiments of the present application are provided, and it can be clearly understood by those skilled in the art that, for convenience and simplicity of description, the specific working processes of the system, the module and the unit described above may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again. It should be understood that the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive various equivalent modifications or substitutions within the technical scope of the present application, and these modifications or substitutions should be covered within the scope of the present application.

Claims

1. A method of non-coherent estimation of a frequency offset, comprising:

respectively carrying out coherent accumulation on multiplication results in N preset time periods to obtain N accumulation results, wherein the accumulation results comprise I components and Q components, N is a positive integer and is more than or equal to 3;

performing incoherent accumulation on the N-1 dot product operation results according to the signs of the dot product operation results to obtain dot product operation accumulation results; performing incoherent accumulation on the N-1 cross product operation results according to the signs of the dot product operation results to obtain cross product operation accumulation results;

2. The method of claim 1, wherein the predetermined time period is a bit period of the GNSS carrier signal.

3. The method of claim 1, wherein the non-coherently accumulating N-1 dot product operation results according to signs of the dot product operation results to obtain dot product operation accumulation results, specifically comprising:

the non-coherent accumulation of the N-1 cross product operation results according to the sign of the dot product operation result to obtain a cross product operation accumulation result specifically includes:

and when the sign of the dot product operation result is negative, accumulating the cross product operation result after negating the cross product operation result.

4. The method of claim 1, further comprising:

acquiring a carrier-to-noise ratio of the received GNSS carrier signal;

when the carrier-to-noise ratio is larger than a preset first threshold, setting the number N of segments of N preset time periods to be larger than a second threshold;

and when the carrier-to-noise ratio is smaller than the first threshold, setting the number N of segments of N preset time periods to be smaller than a second threshold.

5. A method of non-coherent estimation of a frequency offset, comprising:

6. The method of claim 5, wherein the non-coherently accumulating N-1 cross product operation results according to the sign of the dot product operation result to obtain a cross product operation accumulation result, specifically comprising:

7. A frequency offset non-coherent estimation apparatus, comprising:

the calculation module is used for multiplying the digital intermediate frequency signal by a local satellite pseudo-random code signal to obtain a multiplication result;

the calculation module is further configured to perform coherent accumulation on the multiplication results within the N preset time periods to obtain N accumulation results, where the accumulation results include an I component and a Q component, N is a positive integer, and N is greater than or equal to 3;

the calculation module is further configured to perform incoherent accumulation on the N-1 dot product operation results according to the signs of the dot product operation results to obtain dot product operation accumulation results; performing incoherent accumulation on the N-1 cross product operation results according to the signs of the dot product operation results to obtain cross product operation accumulation results;

8. A frequency offset non-coherent estimation apparatus, comprising:

the calculation module is further configured to perform coherent accumulation on the multiplication results within the N preset time periods to obtain N accumulation results, where the accumulation results include an I component and a Q component, where N is a positive integer and is greater than or equal to 3;

the calculation module is further configured to perform a cross product operation on the I component and the Q component of the adjacent accumulation results according to the time sequence for the N accumulation results to obtain N-1 dot product operation results and N-1 cross product operation results;

the calculation module is further configured to perform incoherent accumulation on the N-1 cross product calculation results according to the sign of the dot product calculation result to obtain a cross product calculation accumulation result;

and the frequency discrimination module is used for carrying out sinusoidal frequency discrimination according to the cross product operation accumulation result after the incoherent accumulation so as to obtain a frequency offset incoherent estimation value.

9. An electronic device, characterized in that the device comprises: a processor, and a memory storing computer program instructions; the processor reads and executes the computer program instructions to implement the method of frequency offset non-coherent estimation according to any of claims 1-4, or to implement the method of frequency offset non-coherent estimation according to claim 5 or 6.

10. A computer storage medium having computer program instructions stored thereon, which when executed by a processor implement the method of non-coherent estimation of frequency offset according to any of claims 1-4 or the method of non-coherent estimation of frequency offset according to claim 5 or 6.