# Reception method and receiver for radio-navigation signal modulated with cboc or tmboc propagating signal

FIELD: physics.

SUBSTANCE: to receive a radio-navigation signal modulated by a signal containing a BOC (n_{1},m) component and a BOC (n_{2},m) component, correlation between the current signal at the reception point and the modulating signal, and correlation between the shifted signal at the reception point and the modulating signal is carried out in a time interval with duration T. The current signal at the reception point is generated in form of a binary signal containing one segment of the BOC (n_{2},m) signal with overall duration (1-α_{A})T during the said time interval. The shifted signal at the reception point is generated in form of a binary signal containing one segment of the BOC (n_{1},m) signal with overall duration α_{B}T during the said time interval.

EFFECT: high accuracy of synchronising a received signal with a reference signal.

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The invention relates to a method and receiver for radio navigation signal, the modulated SVOS ("Composite Binary Offset Carrier) or TMBOC ("Time-Multiplexes Binary Offset Carrier) propagating signal.

The prior art inventions

Satellite positioning system such as GPS (global positioning System), Galileo, GLONASS, QZSS, Compass, IRNSS, and others use a modulated navigation signal with spread spectrum. These signals essentially are pseudo-random codes, consisting of periodically repeating number sequences whose main function is to allow multiple access, code distribution Code Distribution Multiple Access - CDMA) and ensuring accurate measurement of the travel time for the transmitted satellite signal. Incidentally satellite positioning signals may also be useful data.

As for GPS, navigation signals are transmitted in the frequency band L1 centered at 1575.42 MHz and the frequency band L2 from the center 1227,6 MHz. The strip L5 with the center 1176,45 MHz will be added during the modernization of GPS. The Galileo satellites will transmit range: E2-L1-E1 (medium range L1 is similar to the plot for GPS), E5a (which according to the nomenclature of Galileo is the range L5, designed for GPS), E5b (centered at the frequency of 1207,14 MHz) and E6 (with center frequency 1278,5 MHz).

Navigation signals are generated by modulating the Central (carrier) frequency. To create a navigation signals have already been installed or, at least, considers various modulation schemes. To ensure interoperability and compatibility between GPS and Galileo, United States of America and the European Union worked out an agreement on certain points relating to the modulation signal in the L1 band, which is used by both systems. More detailed information on the proposed modulation schemes can be obtained from the publication "NGOS: New optimized modulation distribution recommended for GALILEO L1 OS and GPS L1C", Hine, etc. / "NGOS: The new optimized spreading modulation recommended for GALILEO L1 OS and GPS L1C Hein et al., InsideGNSS, may/June 2006, p.57-65.

One of the modulation schemes selected as a candidate for the modulation signal of the Galileo L1 OS, known under the name of "TMOS modulation". Moreover, this type of modulation has already been selected for signal L1C GPS. TMOS propagating signal, modulating the carrier can be described as an alternating sequence of segments of the first signal BOC (n_{1}m), and segments of the second signal VOS (n_{2}, m), where n_{1}>n_{2}. "BOC" refers to the modulation of the double offset of the carrier, which is an abbreviation for "Binary Offset Carrier". In General, the BOC (n, m) is a function which th time t,
defined by the formula:

where C_{m}(t) - pseudo-random code transmission speed of the signal elements×1023 Mcps provided that the values +1 or -1 and f_{sc}is the frequency of n×1.023 MHz. One condition applicable to n and m, is the fact that the ratio 2n/m is an integer. TMBOC_{m}(n_{1}n_{2}) propagating signal is determined by the formula:

where f_{n1}=n_{1}×1.023 MHz, f_{n2}=n_{2×}1.023 MHz, where S_{1}- Association "BOC (n_{1}m)" segments and S2 is the Union of "BOC (n_{2}m)" segments, S1 and S2 are complementary to each other on the time axis, and where C_{m}(t) is a pseudo-random code signal at the transmission rate of the signal elements m×1.023 Mcps and assuming the values +1 or-1. For GPS L1C and Galileo OS L1, m=1, n2=1 and n_{1}=6 will take place as applicable. The ratio between the length of the segments BOC (1,1)and the length of the segments BOC (6,1)" determines how the signal power is distributed between the two components.

Another possible modulation scheme to modulate the signal Galileo L1 OS known as the CBOC modulation". CBOC propagating signal, modulating the carrier, is a linear combination of the first signal BOC (n_{2}m), and the second signal VOS (n_{1}, m). In this case, the signal CBOC_{m}(n_{1}n_{2}) which may be written in the following form:

where V and W are real coefficients that determine the relative weight of the component BOC (n_{2}, m) and BOC (n_{1},.m). In the case of signal CBOC two components BOC are identical pseudo-random code. If this modulation is selected for Galileo L1 OS, it will apply m=1, n_{1}1=6 and n_{2}=1. Modulation CBOC (6,1) signal 10 shown in figure 1.

To determine the propagation time of a signal transmitted by the satellite (pseudoresistance) at the receiver, a method of obtaining a signal contains phase correlation. In the technical field it is well known correlation signal, modulating the radionavigation signal local reference signals of the modulating signal. The modulating signal is at the first detection of an unknown phase, which must be defined to calculate the position of the receiver. The method is usually carried out repeatedly and begins with an initial estimate of the unknown phase of the modulating signal. Then in the receiver produces a current reference signal of the modulating signal, that is, the copy of the modulating signal, the phase of which corresponds to the estimate, which is then correlated with the modulating signal. In parallel produces one or more offsets of the local reference signal of the modulating signal, that is, one or more copies of the modulating signal, the phase of which is about early or late relative to the assessment. This or these offset reference signal is also correlated baseband signal. The results of these correlations are then used to improve the assessment phase of the modulating signal. The method is then repeated as long as the phase is not defined with sufficient precision.

European patent application EP 1681773 describes this method in the case of the modulating signal type CBOC. The incoming signal, the simulated CBOC signal and the local reference signal this signal CBOC are thus correlated. This solution includes generating a reference signal CBOC receiver. Therefore, it is necessary to carry out the four-level quantization on the input of the correlator, which requires at least 2-bit architecture. In the same patent application mentioned second method, in which the correlation is performed between the incoming signal and the local reference signal to the first component BOC and the other correlation is performed between the incoming signal and the local reference signal of the second component BOC. The results of the two correlations are then combined. In this second method the local reference signals are one bit, which can be considered as an advantage with respect to the first solution. The price that you must pay, is doubling the number of correlation operations on sravnenie is with the first solution, everything else is the same.

French patent application 06 05551 is an improved method and an improved receiver for receiving the signal CBOC with component BOC (n_{1}, m) and the BOC (n_{2}, m), where n_{2}<n_{1}. To implement the correlation between the local signal and the CBOC signal transmitted by the satellite in a time interval of duration T, this app offers the generation of a local signal in the form of a binary signal (item 12 in figure 2), formed during the specified time interval, the alternating sequence containing at least one segment of the signal BOC (n_{1}m) 14 and at least one segment of the signal BOC (n_{2}m), 16, with at least one segment VOS (n_{1}m) 14 total duration of (1-α)T, while α is strictly between 0 and 1, and at least one segment BOC (n_{2}m) 16 total duration of (1-α)T. In particular, the method does not include the signal with more than two levels and does not require a larger number of correlators.

Figure 3 shows a simplified diagram of a receiving channel of the receiver, configured to perform the described in FR 06 05551 way. It should be noted that the same local binary signal S_{LOC}used for different correlations.

In the implementation described in FR 06 05551 sposobnastyami,
in particular, if m=1, n_{1}=6 and n_{2}=1, if α increases, i.e. if the local signal S_{LOC}the proportion of the component BOC (6,1) is increased to the detriment of the proportions of the component BOC (1,1), a deterioration of C/N ratio_{0}(the ratio of power From the carrier to the spectral noise density N_{0}) becomes greater, thereby making the signal more difficult. The deterioration of C/N ratio_{0}as a function of the value of the parameter α is shown in figure 4 for two types CBOC modulation signal (one eleventh of the total power in the component BOC (6,1), the other with two eleventh, this distribution of power is mentioned with reference to the example). On the other hand, if α increases, there is also an increase in the working characteristic of the synchronization ("implementation monitoring") and the best resistance to the effect of multipath propagation.

The purpose of the invention

The aim of the invention is to develop innovative ways of receiving a radionavigation signal modulated propagating signal.

General description of the invention

To get a radionavigation signal modulated with the modulating signal, the modulating signal contains a component BOC (n_{1}, m) and the BOC (n_{2}, m), n_{2}is strictly less than n_{1}the correlation is carried out in accordance with the s time interval of duration T between the current signal at the receiving and modulating signal and the offset between the signal at the point of admission (early or late) and the modulating signal.
According to the invention the current signal at the reception point is generated in the form of a binary signal containing within a specified time interval at least one segment of the signal BOC (n_{2}m) total duration of (1-α)T for a specified time interval, while α is a parameter greater than or equal to 0 and strictly less than 1. According to the invention is shifted signal at the reception point is generated in the form of a binary signal containing within a specified time interval at least one segment of the signal BOC (n_{1}m) total length α_{in}T within the specified time interval, with α_{in}is a parameter strictly greater 0 and less than or equal to 1, and α_{A}differs from α_{in}. Except in those cases in which α_{A}=0, current offset signal at the receiving end contains within a specified time interval at least one segment of the signal BOC (n_{i}, m), the total duration of at least one segment is equal to α. Except in those cases in which α_{in}=1, the offset signal at the receiving end contains within a specified time interval at least one segment of the signal BOC (n_{2}, m), the total duration of at least one segment is equal to (1-α_{in})So since α_{A}and α_{in}are different the mi,
the current and the offset signal at the receiving different proportions of segments BOC (n_{1}, m) and BOC (n_{2}, m). So, thanks to the invention can be adjusted separately current and the offset signal at the point of intake to achieve improved reception of navigation signals. This makes it possible, to some extent, to separate the improvement in the implementation of the synchronization from the deterioration of C/N ratio_{0}keeping the advantage of local binary signals.

In the particular case where α_{A}=0, the current signal at the reception point is a local reference signal component BOC (n_{2}, m) of the combined signal during the specified interval correlation. The value of α_{in}can in principle be freely selected within the above range, however, it is preferable, from the upper part of this range, i.e. from 0.8 to 1.

In the particular case where α_{in}=1, the offset signal at the reception point is a local reference signal component BOC (n_{1}, m) of the combined signal during a specified time interval. The value of α_{A}can in principle be freely selected within the above range, however, it is preferable, from the lower part of this range, i.e. from 0 to 0.2.

Preferably, the value of the parameter α_{And}is significantly less than the value of the parameter α_{in
. The case when two conditions αA=0 and αin=1, is regarded as particularly preferred.}

Shifted signal at the point of reception may contain early local signal, and/or late signal, and/or the difference between the early local signal and late local signal. According to a preferred variant of the invention, the correlation is performed on the current channel receiver (between the incoming baseband signal and the current local binary signal), the "late" channel receiver (between the incoming baseband signal and late local binary signal), and "early" channel receiver (between the incoming baseband signal and the early local binary signal). According to another preferred variant of the invention, the correlation is performed on the first channel between the incoming baseband signal and the current local binary signal and the second channel between the incoming baseband signal and a difference early local binary signal and late local binary signal.

It should be noted that the method according to the invention is particularly preferred for receiving a radionavigation signal modulated baseband signal CBOC type, while the latter contains a linear combination with real parameters of the component BOC (n_{1}m), and the component is and BOC (n_{
2}, m). However, the method can also be used for receiving the navigation signal, the modulated baseband signal type TMOS, the latter contains an alternating sequence of segments of the component VOS (n_{1}m), and segments of the component BOC (n_{2}, m). Therefore, the receiver is arranged to implement the method could equally well be taken as signals modulated in accordance with the scheme CBOC and the signals modulated in accordance with the scheme of TMOS that would guarantee the compatibility of GPS L1 C/Galileo L1 OS, even if the CBOC modulation scheme was chosen for Galileo L1 OS.

A receiver for implementing the method contains, preferably, the generators of the local signal to generate a current signal at the reception point and offset of the signal at the receiving end together with the correlators for implementation within a time interval of duration T of the correlation between the current signal at the receiving and modulating signal. These generators local signal is made to generate a specified current signal at the receiving end in the form of a binary signal containing within a specified time interval at least one segment of waveform BOC (n_{2}m) total duration of (1-α)T for a specified time interval, with α_{And}is a parameter greater than or equal to 0 and strictly less is 1,
and for generating a specified offset signal at the receiving end in the form of a binary signal containing over a time interval at least one segment of the signal BOC (n_{1}m) total length α_{in}T within the specified time interval, with α_{in}is a parameter that is different from the parameter α_{A}and strictly greater than 0 and less than or equal to 1.

Preferably, the receiver comprises a generator current signal at the receiving end, the generator is shifted signal at the point of admission, the first correlator equipped with a mixer for mixing the baseband signal with the current signal at the point of reception that proceedeth out of the generator current signal at the receiving end, and the second correlator equipped with a mixer for mixing the baseband signal with an offset signal at the point of reception that proceedeth out of the generator is shifted signal at the receiving end.

Brief description of drawings

Other details and features of the invention will become clear from the detailed description of the preferred variants of the invention given below with the description with reference to the accompanying drawings on which is shown:

Figure 1 temporary image signal CBOC (6,1);

2 temporary image local binary signal formed by a sequence of segments of the BOC (6,1) and BOC (1,1);

Figure 3 schematic of diagra the mA receiver, using the same local binary signal in the current correlator and the correlator offsets;

Figure 4 view of the deterioration of C/N ratio_{0}as a function of the parameter α for receiver figure 3;

Figure 5 representation of the error tracking code as a function of the ratio C/N_{0}for receiver figure 3;

6 is a schematic diagram of the receiver is made with the possibility of implementing a new way;

Fig.7 schematic diagram of another receiver, configured to implement a new way;

Fig the errors view tracking code as a function of the ratio C/N_{0}for the new method with the condition α_{A}=0 and for different values of α_{in}and one comparative case;

Fig.9 output of the discriminator as a function of the difference between the code of the incoming signal and the local code for the new method, with the condition α_{A}=0 and for different values of α_{in}and one comparative case.

Detailed description

Figure 1 shows the signal 10 CBOC (6,1)defined by the formula:

where V and W are weighting factors. Here and below the transmission rate of the elements of the pseudorandom signal code is set to 1, thus allowing to skip the index "m" in the legend, presents uravnenii the mi(1)-(3).

Different values of V and W are considered to signal the Galileo OS L1 depending on the multiplexing scheme of this signal. Used, for example, the legend CBOC (6,1,1/11), CBOC (6,1,2/11). Indexes 1/11 and 2/11" refers to the multiplexing scheme for the radionavigation signal and reference the specific weight of component BOC (1,1) and BOC (6,1). For SWOS (6,1, 1/11) V=0,383998 and W=0,121431, for CBOC (6,1, 2/11) V=0,358235 and W=0,168874. The sign "+" or "-" is sometimes used to refer to what precedes whether the "+" or "-" coefficient of W in equation (4): for example, SWOS (6,1, 1/11,-) or SVO (6,1, 1/11,+).

To ensure the best presentation of the advantages of this invention should first discuss the deterioration of C/N ratio_{0}, performance synchronization and multipath resistance in the case of a method of receiving a radionavigation signal, which uses the same local binary signal 12 on the current channel correlation and channel correlation bias, when the specified signal is generated within the correlation interval (time T) by alternating the sequence containing at least one segment of the signal BOC (6,1) 14 and at least one segment of the signal BOC (1,1) 16, and at least one segment of the BOC (6,1) 14 total duration α, and α is strictly between 0 and 1, α is at least one segment of the BOC (1,1)16 total duration of (1-α)T.
β=1-α and S_{LOC}(α) will be designated as local binary signal.

Shown in figure 3, the receiver includes a correlator 18.1-18.6, each of which has a mixer 20.1-20.6, which mixes the incoming signal type SWOS with a local copy of the binary signal S_{LOC}shown in figure 2 type, and the integrator 22.1-22.6, which integrates mixed signals and produces an output signal. The first "early" correlator 18.1 provides a correlation value of I_{E.SLOC(α)}the common mode part of the incoming signal CBOC (t-τ) and "early" copylocal binary signal S_{LOC}(τ is a pseudo-random phase code of the received signal, andis the assessment τ, Δ is the duration of the chip and n defines the length of the chip, whereby the local copy of the binary signal is relatively early assessment.) The second correlator 18.2 is "current" correlator that delivers the value of I_{P,SLOC(α)}correlation in-phase part of the incoming signal CBOC (t-τ) and a current copylocal binary signal. The third correlator is 18.3 "late" correlator that delivers the value of I_{LSLOC(α)}correlation in-phase portion of the input signal s_{LOC}(t-) and "late" copy of s_{LOC(α)}(t-
+Δ/n) local binary signal S_{LOC}. The correlator 18.4 supplies the correlation value Q_{E.SLOC(α)}the quadrature part of the incoming signal CBOC (t-τ) and "early" copy of s_{LOC}(t--αΔ/n) local binary signal S_{LOC}. The correlator 18.5 supplies the value of Q_{P,SLOC(α)}correlation of the quadrature part of the incoming signal SVOS (t-and current copy of s_{LOC}(t-local binary signal. The correlator 18.6 supplies the value of Q_{L.SLOC(α)}correlation of the quadrature part of the incoming signal CBOC (t-τ) and "late" copies of s_{LOC}(t-+Δ/n) local binary signal S_{LOC}.

This results in the following output of correlator:

where "X" represents the channel correlation when considering (X=L: late channel correlation, X=P: current channel correlation, X=E: early channel correlation), R_{BOC(6,1)}the autocorrelation function of the signal BOC (1,1); R_{BOC(6,1)}the autocorrelation function of the signal BOC (6,1) and R_{BOC(1.1)/BOC(6.1)}- the correlation function between the signal BOC (1,1) and the signal BOC (6,1); ε_{t}- the difference between the phase of the local pseudo-random code, the evaluation phase τ pseudo-random code of the incoming signal and the phase τ; ε_{φ}- the difference between the phase
carrier local signal and the phase φ; δ_{x}=-Δ/n for X=E, δ_{x}=0 for X=P and δ_{x}=+Δ/n for X=E, and r represents the correlator output noise.

Correlation R_{CBOC/CLOC(α)}signal of SWOS defined in the formula (4) and correlation of local binary signal S_{LOC(α)}will be discussed below:

The autocorrelation function R_{SLOC(α)}local binary signal S_{LOC(α)}can be approximately expressed as:

and the autocorrelation function R_{CBOC}function CBOC written as:

The deterioration of C/N ratio_{0}can be formulated as:

that means that the higher the value of α, the greater the loss of signal correlation relative to the case in which the reference signal CBOC is used as a local signal. The deterioration of C/N ratio_{0}shown in figure 4 for the reception of signals CBOC (6,1, 1/11) (curve 24) and signal CBOC (6,1, 2/11) (curve 26). It should be noted that to obtain the deterioration of C/N ratio_{0}less than 3 dBs, the value of α should be chosen in the range from 0 to 0.4.

The output values of the correlator used in the loop to minimize the values of e_{t}. For example, it is possible to compute the discriminator scalar D works (discriminator scalar product):

The resulting theoretical error tracking code is formulated as:

where the filtered autocorrelation function given by the formula:

and filtered functions intercorrelation given by the formula:

In the above equations (11)-(11") represents the bandwidth of the RF filter head (filter here is assumed to be rectangular), B_{L}- band loop filter DLL, T is the integration time used for correlation, P is the power used by the input signal; d is the interval between the early local signal and late local signal, N_{0}- the level of the spectral density of thermal noise and G_{x}- the Fourier transform-signal X.

Error tracking code is represented as a function of the ratio C/N_{0}figure 5 for different values of and, in the case of a tracking signal CBOC (6,1, 2/11, "-") distance in 0.1 chip between early local binary signal and late local binary signal, 12 MHz input filter (one-sided) and 4 MS integration time (for correlation). It can be noted that the error decreases when α increases. Based on the implementation of synchronization, it would be preferable to choose α close to 1. In fact, from the above it is seen that for this value the deposits of α deterioration of C/N ratio_{
0}is essential.

It should also be noted that for α=0,2 envelope when multipath propagation is equivalent to that obtained when using the CBOC (6,1, 2/11, "-") reference signal as a local signal.

According to this invention uses a different current and offset signals at the receiving end. This makes it possible to optimize shifted signals at the point of admission regardless of the current signal at the point of reception. Figure 6 shows a diagram of the first receiver 60, is arranged to implement the method. The receiver includes a correlator 62.1-62.6, each of which has a mixer 64.1-64.6, which mixes the incoming signal CBOC type to the local copy of the binary signal, and the integrator 66.1-66.6 that integrates mixed signals and produces an output signal.

The receiver has a set of generators 68.1-68.3 local binary signal. Generator 68.1 generates an early copy of s_{LOC/2}(t--Δ/n) local binary signal s_{LOC2}. The signal s_{LOC2}contains over a correlation interval segment of the signal BOC (6,1) total duration α_{In}T, if α_{B}≠1, the segment signal BOC (1,1), duration (1-α_{B})So now we assume that α_{B}located in the half-open interval]0,1], which allows to address a particular case α_{B}=1 at the same time as in other cases.
If α_{B}=1, s_{LOC2}is a pure signal BOC (6,1). For values of α_{B}strictly less than 1, s_{LOC2}also contains a segment of the BOC (1,1) and may, for example, have the appearance of the signal 12 figure 2. Generator 68.3 generates a late copy of s_{LOC/2}(t-+Δ/n) local binary signal s_{LOC2}. Generator 68.2 generates a current copy of S_{LOC1}(t-local binary signal s_{LOC1}. The signal s_{LOC1}contains over a correlation interval segment of the signal BOC (1,1) with a total duration of (1-α_{A})T if α_{A}≠0, the segment signal BOC (6,1) duration α_{A}T. suppose Further that α_{A}located in the half-open interval [0,1[. If α_{A}=0, S_{LOC1}is a pure signal BOC (1,1). For values of α_{And}strictly big 0, S_{LOC2}also contains a segment of the BOC (6,1) and may also have the appearance of the signal 12.

The correlator 62.1 supplies the correlation value of the I_{E.SLOC2(t-t)}the common mode part of the incoming signal CBOC (t-τ) and "early" copy of s_{LOC2}(t--Δ/n) local binary signal S_{LOC2}. (As noted above, τ is the phase of the pseudorandom code of the received signal, andassessment τ, Δ is the duration of the chip and the n - defines the duration of the chip, whereby the local copy of the binary signal which is relatively early assessment
). The correlator 62.2 is "current" correlator that delivers the value of I_{P,SLOC1(αA)}correlation in-phase portion of the input signal, SWOS (t-τ) and a current copy sLOC(τ-local binary signal S_{LOC1}. The correlator is 62.3 "late" correlator that delivers the value of I_{L,SLOC2(αB)}correlation in-phase part of the incoming signal CBOC (t-τ) and "late" copies of s_{LOC2}(t-+Δ/n) local binary signal S_{LOC2}. The correlator 62.4 supplies the correlation value Q_{E,SLOC2(αB)}the quadrature part of the incoming signal CBOC (t-τ) and "early" copy of s_{LOC2}(t--Δ/n) local binary signal S_{LOC2}. The correlator 62.5 supplies the value of Q_{P,SLOC1(αA)}the quadrature part of the incoming signal CBOC (t-τ) and a current copy of s_{LOC1}(t-local binary signal S_{LOC1.}The correlator 62.6 supplies the value of Q_{L,SLOC(αB)}correlation of the quadrature part of the incoming signal CBOC (t-τ) and "late" copies of s_{LOC2}(t-+Δ/n) local binary signal S_{LOC2.}Reasons of clarity, Fig.6 shows only connections, respectively, of the generators 68.1, 68.2 and 68.3 to mixers 64.4, 64.5 and 64.6. Connection to mixers 64.1, 64.2 and 64.3 are not shown.

7 shows a schematic diagram drugog the receiver 70, made with the possibility of implementing the method. The receiver 70 includes correlators 72.1-72.4, each of which has a mixer 74.1-74.4, which mixes the incoming signal CBOC type to the local copy of the binary signal, and the integrator 76.1-76.4, which integrates mixed signals and produces an output signal.

The receiver has a set of generators 78.1-78.3 local binary signal. Generator 78.1 generates an early copy of s_{LOC2}(t--Δ/n) local binary signal S_{LOC2.}Generator 78.3 generates a late copy of s_{LOC2}(t-+Δ/n) local binary signal S_{LOC2}. Generator 78.2 generates a current copy of s_{LOC1}(t-local binary signal s_{LOC1}. The signals S_{LOC1}and S_{LOC2}have been identified in the description of 6. The adder 77 produces the difference between early copy of s_{LOC2}(t--Δ/n) and late copy of s_{LOC2}(t-+Δ/n) local binary signal S_{LOC2}that it receives from the generators and 78.1 78.3. The difference is entered in the mixers 74.1 and 74.3. The correlator 72.3 supplies the correlation value Q_{E,SLOC2(αB)}-Q_{L,SLOC2}(αB) of the quadrature part of the incoming signal CBOC (t-τ) and the difference between early and late copies of the local binary signal S_{LOC2}. The correlator 72.4 supplies the value of Q_{P,SLOC1(αA)/sub>
correlation of the quadrature part of the incoming signal CBOC (t-τ) and current copies of sLOC1(t-)local binary signal SLOC1.}

In both types the implementation of the new method can calculate the discriminator scalar product, which is formulated as follows:

For reception of a signal CBOC (6,1, 1/11) or CBOC (6,1, 2/11) the most important drawback of this approach use the same local binary signal on the current channel and the channel offset was loss of correlation. With this invention the current signal at the reception point can be selected with a greater proportion of the signal BOC (1,1), conducted without thereby reducing the aspect ratio of the signal BOC (6,1) in early or late local signals that improve synchronization.

Below will be discussed special case α_{A}=0, i.e. the case in which the current signal at the reception point is a signal BOC (1,1). The first consequence is that the loss of correlation (deterioration of C/N ratio_{0}in the phase tracking (which uses only the current correlators) is minimal (about 0.9 dBs signal CBOC (6,1, 2/11) and approximately 0.5 dBs signal CBOC (6,1, 1/11), as can be seen in figure 4).

Theoretical error tracking code is achieved with α_{A}=0 and the drive is imination scalar product:

It should be noted that the square member of correlation between local binary signal and BOC (6,1) modulation signal represented in equation (11), is replaced here by a square member, which is great. Therefore, the quadratic error tracking code decreases when decreasing α_{A}.

It is shown that for the modulating signal CBOC (6,1, 2/11, '-') standard deviation error tracking code decreases for all ratios of C/N_{0}if it increases the value of the parameter α_{B}(α_{A}=0). The best implementation tracking is obtained in the limiting case α_{B}=1 (pure BOC (6,1) in the form of early and late local signal).

Theoretical predictions were tested using a model with the following settings:

+ the reception signal of SWOS (6,1, 2/11, "-") with a duration of 40;

+ integration time of 4 MS;

+ automatic adjustment delay (DLL loop) with support for the carrier and having a bandwidth of 1 Hz;

+ system phase-locked loop (PLL loop having a bandwidth of 10 Hz, the discriminator based only on the quadrature portion;

+ bandwidth of 10 MHz input (one-way).

The results of the simulations shown in Fig and in tables 1-3.

Table 1 | |||

C/N_{0}(dB-Hz) | C/N_{0}deterioration (dB) | ||

CBOC | α_{in}=0.5 | α_{in}=1 | |

30 | 0 | -0.50 | -0.49 |

35 | 0 | -0.54 | -0.54 |

40 | 0 | -0.55 | -0.55 |

45 | 0 | -0.56 | -0.56 |

50 | 0 | -0.56 | -0.56 |

Table 2 | |||

C/N_{0}(dB-Hz) | The standard deviation of the error tracking ID (m) | ||

CBOC | α_{in}=0.5 | α_{in}=1 | |

30 | 0.467 | 0.653 | 0.467 |

35 | 0.241 | 0.336 | 0.242 |

40 | 0.112 | 0.154 | 0.138 |

45 | 0.074 | 0.102 | 0.075 |

50 | 0.043 | 0.063 | 0.046 |

Table 3 | |||

C/N_{0}(dB-Hz) | The standard deviation of the error tracking phase (rad) | ||

CBOC | α_{in}=0.5 | α_{in}=1 | |

30 | 0.0841 | 0.0904 | 0.0909 |

35 | 0.0461 | 0.0492 | 0.0493 |

40 | 0.0252 | 0.0267 | 0.0267 |

45 | 0.0144 | 0.0154 | 0.0154 |

50 | 0.0075 | 0.0079 | 0.0079 |

Figure 9 shows the discriminator scalar product (via I_{P,SLOC(α)}^{2}+Q_{P,SLOC(α)}^{2}=I_{P,BOC(1,1)}^{2}+Q_{P,BOC(1,1)}^{2}to receive the signal SVOS(6,1, 2/11, '-') for different values of α_{B.}By comparison, also shown is the curve obtained by using the local signal CBOC (6,1, 2/11, '-'). For larger values of α_{In}more pronounced wrong point tracking. Thus, it should be made clear tracking method. The curves in figure 9 were obtained using the following parameters: length 0.1 chip between early local binary signal and late local binary signal, the input filter 15 MHz (one-sided) and 4 MS integration time (for correlation).

With regard to multipath propagation, it is obvious that the greater the proportion of the BOC (6,1) local binary signal, the closer the resulting envelope errors when multipath propagation is coming to envelope errors multipath propagation of the local signal BOC (6,1). It is difficult to see how the working accuracy of the statistics,
based on multipath propagation, influenced for values of α_{in}≥0,3. However, it is assumed that the operating characteristic remains approximately the same. In this case, in light of the above analysis is probably preferable to use the larger value of α_{B}close to 1 or even equal to 1.

A detailed analysis of the operating characteristics of the new method it is assumed that α_{A}=0. It is obvious that similar working characteristics can be obtained for values of α_{A}close, but other than 0. Also noticed that the optimal choice of α_{A}and α_{B}will be greatly dependent on the modulating signal radionavigation signal. This may be the CBOC signal, as indicated in the detailed description, or alternatively, once again, the signal type TMBOC, as expected for a signal L1C GPS.

In the analysis discussed only the discriminator scalar product. However, it should be noted that there are other discriminatory, which can also be used to implement the present invention, in particular early-minus-late" or "current" discriminator, for example, to determine the phase of the incoming signal.

Also it should be mentioned that to obtain multiple transmitted by the satellites signals to the receiver, you must have a lot of channels when the mA. For each receive channel receiver, there is a set of correlators, as described in this invention, the output signals are combined to generate the detection signal energy estimation of the received signal, and the tracking mode signal discriminator pseudo-random code.

1. The method of receiving a radionavigation signal modulated baseband signal, with a modulating signal contains a component VOS (n_{1}m), and component VOS (n_{2}, m), where n_{1}different from the n_{2}and VOS (n, m) each time is determined by the function of time t according to the formula:

VOS(n, m)(t)=C_{m}(t)·sign[sin(2πf_{sc}t)],

where t is time, C_{m}(t) - pseudo-random code transmission speed of the signal elements m·1023 Mcps, provided that the values +1 or -1 and f_{sc}is the frequency n·1.023 MHz, and n and m are integers selected so that the ratio 2n/m is an integer,

moreover, with the implementation of the method is performed within a time interval of duration T, the correlation between the current signal at the receiving and modulating signal, and the correlation between the shifted signal at the receiving and modulating signal

characterized in that

the current signal at the reception point is generated in the form of a binary signal containing within a specified time interval at least one segment of waveform BOC (n_{2
m) total duration of (1-αA)T within the specified time interval, with αAis a parameter greater than or equal to 0 and strictly less than 1, and the fact thatshifted signal at the point of reception is generated in the form of a binary signal containing within a specified time interval at least one segment of waveform BOC (n1m) total length αBT within the specified time interval, with αBis a parameter strictly greater 0 and less than or equal to 1, and the parameters αAand αBare various.}

2. The method according to claim 1, in which α_{A}0.

3. The method according to claim 1, in which α_{B}is 1.

4. The method according to claim 2, in which α_{B}is 1.

5. The method according to claim 1, in which α_{A}less than α_{B}.

6. The method according to claim 1, in which the current signal at the receiving end contains within a specified time interval at least one segment of waveform BOC (n_{1}m) total length α_{A}T during a specified time interval, with α_{A}is strictly between 0 and 1.

7. The method according to claim 1, in which the offset signal at the receiving end contains within a specified time interval at least one segment of waveform BOC (n_{2}m) total duration of (1-α_{B})T within the specified time interval, with α_{B}located straw is about between 0 and 1.

8. The method according to claim 1, in which the offset signal at the receiving end contains early local signal, or late local signal, or the difference between the early local signal and late local signal.

9. The method according to claim 1, in which n_{2}=1, n_{1}=1 and m=1.

10. The method according to one of claims 1 to 9, in which a modulation signal which modulates the radio-navigation signal is the modulating signal type SVO, with a modulating signal type SWOS contains a linear combination with real parameters of the component VOS (n_{1}m), and component VOS (n_{2}, m).

11. The method according to one of claims 1 to 9, in which a modulation signal which modulates the radio-navigation signal is the modulating signal type TMOS, with a modulating signal type TMOS contains an alternating sequence of segments of the component VOS (n_{1}m), and segments of the component VOS (n_{2}, m).

12. A receiver for receiving a radionavigation signal modulated baseband signal, with a modulating signal contains a component VOS (n_{1}m), and component VOS (n_{2}, m), where n_{1}different from the n_{2}and VOS (n, m) each time is determined by the function of time t according to the formula:

VOS(n, m)(t)=**C**_{m}(t)·sign[sin(2πf_{sc}t)],

where t is time, C_{m}(t) - pseudo-random code transmission speed of the signal elements m·1023 Mcps, provided that the values +1 or -1 and f_{
sc}is the frequency n·1.023 MHz, and n and m are integers selected so that the ratio 2n/m is an integer,

the receiver contains the generators of the local signal to generate a current signal at the reception point and offset of the signal at the receiving end together with the correlators for implementation within a time interval of duration T of the correlation between the current signal at the receiving and modulating signal, and the correlation between the shifted signal at the receiving and modulating signal

the generators of the local signal is made to generate the current signal at the receiving end in the form of a binary signal containing within the specified time interval at least one segment of waveform BOC (n_{2}m) total duration of (1-α_{A})T within the specified time interval, and α_{A}is a parameter greater than or equal to 0 and strictly less than 1,

and to generate a shifted signal at the receiving end in the form of a binary signal containing within a specified time interval at least one segment of waveform BOC (n_{1}m) total length α_{B}T within the specified time interval, and α_{B}is a parameter that is different from the parameter α_{A}and strictly greater 0 and less than or equal to 1.

13. The receiver section 12, containing the generator current SIG is Ala at the point of reception, the generator is shifted signal at the point of admission, the first correlator equipped with a mixer for mixing the baseband signal with the current signal at the receiving end, and the second correlator equipped with a mixer for mixing the baseband signal with an offset signal at the point of reception.

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FIELD: radio engineering.

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FIELD: physics.

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29 cl, 6 dwg, 5 tbl

FIELD: physics.

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FIELD: physics.

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5 cl, 2 dwg

FIELD: physics.

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40 cl, 9 dwg

FIELD: information technology.

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EFFECT: high accuracy of position finding.

8 cl, 3 dwg

FIELD: physics.

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1 dwg

FIELD: physics.

SUBSTANCE: device includes a GPS/GLONASS receiver, an antenna, a user interface (keyboard, display, sound), a communication interface, nonvolatile memory, a microcontroller, consisting of a unit for calculating the coordinate vector from code measurements, a unit for calculating the increment of the coordinate vector from phase measurements, a filter unit based on a least-square method, a unit for calculating a specified coordinate vector from the filtration results, a unit for working with interfaces, where the microcontroller includes a unit for analysing stability of the phase solution, a unit for evaluating duration of measurements and geometrical factor of the constellation of satellites, as well as a correcting unit consisting of a counter for counting stable solutions and a decision unit for deciding on continuing measurements, interfaces for time marking external events and outputting the second mark.

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1 dwg

FIELD: physics.

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14 cl, 34 dwg