Mode of preparation of initial data of range-difference navigational task

FIELD: the invention refers to the field of radio technique and may be used in range-difference systems of definition of the position of the sources of radio emissions.

SUBSTANCE: the mode is based on measuring of two differences of distances Δr12 and Δr13 to two pairs of mobile supporting points {O1,O2}and {O1,O3 , } the coordinates ,j= 1,2,3 supporting points Oj in the moment of time of measuring of distances, then the vector of measured values is transformed into the vector of the coordinates of the three points F1,F2 and M belonging to a hyperbolina: the vector is stored and transmitted along the channels of transmitting information into the center of processing information for using it in quality of initial data at solution a range-difference navigational task; at that the points F1 and F2 defines the focuses of the hyperbolina if it is a hyperbola or an ellipse or a focus and its projection on a directrix if it is a parabola and the third point belongs to the hyperbolina in such a manner that the position of its project on the direct F1F2 defines the form of the curve of the second order.

EFFECT: decreases volume of stored and transmitted data.

5 dwg

 

This proposal relates to the field of radio engineering and can be used in a differential-ranging systems location (WMD) emitters (IRI) to reduce the amount of stored and transmitted data on the results of the measurements required to calculate the coordinates of Iran.

Differential-ranging systems are multilateration systems WMD, Iran [1]. To measure the difference of the distances in REM systems WMD different methods are used: phase, frequency and time [2].

Known methods and devices for fault-based RDM method [1-11 and others].

One of the types of RDM systems WMD are multi-satellite space systems [e.g., 4], in which the role of reference points play a SPACECRAFT). When this share based systems for WMD, Iran groups of three and four KA.

The system of three SPACECRAFT allows to determine the coordinates of Iran, located on the surface of the Earth, and the system of the four SPACECRAFT allows to determine the coordinates of Iran, located on the Earth's surface and flight-lifting means (in space).

Examples of space mission systems using groups of three SPACECRAFT are white cloud (USA) [12], Roy (France) [13].

In these systems, the signal ground IRI taken three KA, which makes it possible to measure the difference of the distances from the RI to the two pairs of SPACECRAFT by measuring the difference of times of reception of the signal.

The algorithm to calculate the coordinates of the IRI is to determine the points of intersection of the two hyperboloids, asked differential-ranging measurements, and the Earth's surface [4].

The original system of equations has the form

where Δr1j=r1-rj, j=2, 3 is the difference of the distances from a pair of support points {O1Oj} to IRI,

the vector of desired coordinates of IRI in the geocentric coordinate system XYZ (GCSC [2]),

- coordinate vector of the j-th anchor point in GCSC (arrangement of reference points and IRI in GCSC shown in figure 1).

To solve this system of equations required input data in the form of values of two varieties of ranges Δr12and Δr13, GCP coordinates (coordinates of the SPACECRAFT at the time of measuring Δrij), as well as the values of the local radius of the Earth RCat the point of location of the IRI.

Thus, the vector of initial data for solutions of RDM navigation task consists of 12 scalar values: 9 coordinate three KAtwo values of the differences between the rangesas well as the values of RC. When thisandare the results a RCrefers to the a priori weight is Emim source data. For rough calculations of the coordinates of the IRI value of RCmay be taken equal to the average radius of the globe. For more precise WMD IRI using an iterative procedure, the essence of which consists in the following. In the first step as the value of RCis some evaluation(for example, the average radius of the Earth); the result of solving the system of equations defined by coordinates of Iran, and is the local radius of the Earth at the point obtained by the coordinate is used to re-solve the original system of equations in order to specify the coordinates.

In [4] described the method of preparation of initial data for solutions of RDM navigation tasks, which includes the following operations:

measure the difference ranges Δr12and Δr13from Iran to couples moving control points {O1O2} and {O1O3};

- measure coordinatesreference points Ojat the time of the measured distances;

the vector of measured valuestore and transmit the channel information to the information processing center to use as the source data in solving navigation tasks (determining the coordinates IRI).

While there are various options for obtaining the source data d is to be placed REM navigation tasks:

- determined on Board one of the AC group (for example, CA, see figa);

- defined in paragraph receiving information (PPI) (see figb);

- determined by ground-based means for measuring motion parameters KA;

- determined onboard by means of the AC.

Due to the fact that the SPACECRAFT can be in the footprint of PPI and ground-based measurements for a limited time, the most appropriate is when the values ofanddetermined onboard by means of the SPACECRAFT and transmitted to the AUP from time to time (when possible) as many odinnadtsatikratnyh vectors of the original data of the navigation tasks, where each vector corresponds to the results of observation of the same IRI.

This method is chosen as a prototype.

The disadvantage of this method is the need for storage and transmission over the radio link KA-PPI significant amounts of data.

The aim of the invention is to reduce the amount of stored and transmitted data by replacing odinnadtsatiletnego vector source data equivalent on the information contained in the vector smaller the size of the property.

This objective is achieved in that the vector of initial data REM navigation tasks containing the coordinate values of the three reference points (O1O2O3) and two varieties ranges from IRI to two pairs of these reference points, processed, and evaluated the parameters of a spatial curve which is the intersection of the two hyperbolic surfaces provisions IRI corresponding to values Δr12and Δr13the values of(gierbolini [14, 15]).

The proposed method involves the following operations:

measure the difference ranges Δr12and Δr13from Iran to couples moving control points {O1O2} and {O1O3};

- measure coordinatesreference points Ojat the time of the measured distances;

- convert the vector of measured valuesin vectorcoordinates of three points that belong hypersaline;

- vectorstore and transmit the channel information to the information processing center to use as the source data in solving navigation tasks (determining the coordinates IRI).

The principle underlying the proposed method consists of the following is relevant.

For convenience and clarity, further introduce into consideration the coordinate system Oxyz set so that its origin coincides with the midpoint of the segment O1O2the ox axis collinear to the vectorand the plane HOU coincides with the plane of O1O2O3(see figure 3). Then in the system Oxyz O1(-a,0,0), O2(a,0,0} and O3(x3,y3,0),

where a=|O1O2|/2,

x3=(b2-with2)/a,

b=|O1O3|/2,

c=|O2O3|/2,

and, therefore, can be written

Erected in the square right and left side of equation (1), we obtain

consequently,

If you expand the brackets in the left part and make simplifications, equation (2) takes the form of the canonical equations to two hyperboloid of rotation

where

Thus, from the above reasoning it follows that the location of Iran belongs to the surface described by equation (3).

Similarly, typing in consideration of the coordinate system O h u z', the beginning of which coincides with the midpoint of the segment O1O3the axis O x' collinear in choru and the plane h O y' coincides with the plane of O1O2O3you can get the location of Iran belongs to the surface described by the equation

where

x',y',z' coordinates of IRI in the coordinate system O'x'y'z'.

Because the location of Iran belongs simultaneously to two surfaces, therefore, it belongs to the line of intersection of these surfaces.

On the other hand, the hyperboloid is defined by its focus directorially plane and eccentricity [16]

r=s·d

where r is the distance from the point of the hyperboloid to focus.

d - the distance from the point of the hyperboloid to directorially plane;

ε>1 - eccentricity (fixed value).

Therefore, the line of intersection of two hyperboloids with a common focus (gierbolini) is described by a system of equations

where r is the distance from point gierbolini to focus.

Therefore

Equation (5) represents the equation of the plane. Therefore, all points gierbolini belong to one plane, described by equation (5). Since all points gierbolini at the same time belong and the hyperboloid of rotation, therefore, hyperbolise the two the is curve of the second order (other more obvious evidence of this fact is given in [15]).

Therefore, the vector data sourceuniquely corresponds to the curve of the second order, which is the line position on Iran, and instead of a vector, you can send a description gierbolini. A minimal set of data sufficient to describe the curve of the second order in three-dimensional space, are the coordinates of three points that belong to a given curve.

Standard form gierbolini is a hyperbola or an ellipse, and in some cases the parabola. It is therefore necessary to consider the possibility of transmission in the vector of coordinates of the three pointscharacterizing hypersaline, information about the form gierbolini and its parameters.

For the ellipse and hyperbola, it is advisable to transfer the coordinates of the foci F1and F2and the point M belonging hypersaline. For ellipse - coordinates of the point M'orthogonal projection on which a straight F1F2belongs to the segment [F1O], where |F1O|=|F1F2|/2, and for the hyperbola - coordinates of the point M, the orthogonal projection on which a straight F1F2does not belong to the segment [F1F2]. For a parabola, it is advisable to transfer the coordinates of the focus F1points F2which PR is under the point F 1on directorially plane, and the point M'orthogonal projection on which a straight F1F2belongs to the segment [OF2]where |OF2|=|F1F2|/2 (figure 4).

There odinnadcatiletnij vectorto reduce the amount of transmitted data without loss of information about the location of the IRI can be replaced deletecomponent vector

Thus, the proposed method is compared with the prototype provides the possibility of reducing the amount of stored and transmitted data by replacing odinnadtsatiletnego vector source data equivalent on the information contained dietitianenergy vector.

The proposed method can be applied in surveillance systems, and navigation systems. It allows you to reduce the volume of stored and transmitted data at 18%, which can be used either to increase the efficiency of the information transmission process, or to improve the quality of communication through the use of error-correcting redundant encoding.

References

1. Multi-radio system / Wascontrolled, Aratow, Lntercom; edited by Prof. OTA. - M.: Radio and communication, 1986. - 264 C.

2. Shortcuts, MS Statistical theory of regionaliga the AI. - M.: Radio and communication, 1985. - 344 S.

3. Sibel A.G. Differential-ranging method of direction finding emitters and realizing it device. RF patent №2204145 from 10.05.2003.

4. Network satellite navigation system / Usershave, Ali, Nevanac and others; Ed. FAV and Wasserchemie. - M.: Radio and communication, 1982. - 272 p, 1993. - 415 S.

5. The dulevich V.E., Korostelev, A., Miller Y.A. and other Theoretical bases of radar / edited Vaitulevich. - M.: Owls. radio, 1964. - 732 S.

6. Theoretical bases of radar. Textbook for high schools / Under the editorship Aderman. - M.: Owls. radio, 1970. - 560 C.

7. Finkelstein M.I. fundamentals of radar. - M.: Owls. radio, 1973. - 496 S.

8. Belotserkovsky G.B. fundamentals of radar and radar devices. - M.: Owls. radio, 1975. - 336 S.

9. Klimenko, N., Klimenko S.V. current state of theory and practice of radiointerference // Foreign Radioelectronics, 1990, No. 1. - P.3-14.

10. The method of determining the location of the transmitter by measuring the difference of the delay times. Pat. GDR 274102.

11. Method hyperbolic determine where and device for its implementation. Pat. GDR 229866.

12. Andronov A. Space electronic reconnaissance system of the U.S. Navy "white cloud" // aubinoe military review, 1993, No. 7. - P.57-60.

13. Zuravin Y. French Secret "Roy" // news of cosmonautics, t is m, No. 3, 2005. - P.55-56.

14. Snow, D.A. Mutual intersection of three related hyperbolic surfaces provisions of the detected object // Radiotekhnika, No. 12, 1994, s-14.

15. Sibel A.G. Form gierbolini // Electromagnetic waves and electronic systems, 2002, No. 9, pp.37-39.

16. Korn G.A., Korn T.M. Handbook of mathematics for scientists and engineers. Definitions, theorems, formulas. / Under the General editorship Igirimbabazi. - M.: Nauka, 1984. - 831 S.

The method of preparation of initial data differential-ranging navigation tasks, based on the measurement of two varieties of ranges Δr12and Δr13from the emitters to the two pairs of movable control points {O1O2} and {O1About3}, coordinatesj=1, 2, 3 anchor points Aboutjat the time of the measured distance, wherein the transform vector of measured valuesin vectorcoordinates of three points of F1F2and M belonging hypersaline; vectorstore and transmit the channel information to the information processing center to use as the source data when solving differential-ranging navigation tasks; at this point F1and F2define the tricks gierbolini, e is whether it is a hyperbola or ellipse, or focus and its projection on the headmistress, if it is a parabola, and the third point belongs hypersaline so that the position of its projection on a straight line F1F2defines the shape of the curve of the second order.



 

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