RU120240U1 - SYSTEM FOR DETERMINING THE LOCATION OF A MOBILE OBJECT BY SIGNALS OF GLOBAL NAVIGATION SATELLITE SYSTEMS - Google Patents

Abstract

A system for determining the position of a mobile object based on signals from global navigation satellite systems, containing a space segment in the form of navigation spacecraft (NSA), a repeater located on a mobile object, which receives signals from an NSA and retransmits them, and a ground segment in the form of a ground measuring point (NIP) , receiving signals from the satellite and the repeater, while the repeater contains a serially connected receiver of signals from the satellite, a carrier frequency converter and a transmitter of relayed signals, and the NIP contains a serially connected unit for receiving and processing signals from the satellite, a correction unit and a unit for calculating the coordinates of the location of the repeater, the signal input of which is connected with the output of the unit for receiving and processing the signals of the repeater, characterized in that the correction unit contains a unit for calculating the ionospheric delay and a unit for calculating the error of ephemeris-time support (EVO) The first and second inputs of the correction unit are connected to the output of the unit for receiving and processing signals from the NSA, and the outputs, which form the first and second outputs of the correction unit, respectively, are connected to the first and second correcting inputs of the unit for calculating the coordinates of the location of the repeater, while the second input of the unit for calculating the error The EVO of the NSA is connected to the output of the meteorological data block, the second input of the ionospheric delay calculating block is connected to the output of the ionospheric data block, and the third input of the ionospheric delay calculating block is connected to the output of the repeater position pre-calculating block, the input of which, forming

Description

The utility model relates to the field of radio navigation and can be used in systems for determining the location and tracking the trajectory of objects moving in the above-ground space according to the signals of global navigation satellite systems (GNSS) GLONASS, GPS and the like.

Known systems for determining and tracking the location of moving objects by GNSS signals, in which the current coordinates of the trajectory of movement are determined on board the positioning object using the appropriate on-board navigation receivers, and then at certain times are transmitted over the air to the control point, where they are recorded and, if necessary are visualized, see, for example, patents: [1] - EP 0509775 A2, G01S 19/42, G01S 5/00, G01S 5/14, 10.21.1992; [2] - US 5025261, H04B 7/185, G01S 5/02, 06/18/1991; [3] - US 5644317, G01S 5/02, G01S 3/02, G01C 21/00, 01/01/1997. At the same time, onboard the positioning object, the navigation radio signals emitted by the GNSS navigation spacecraft (NSA) are received and their parameters are processed: the frequencies of the received radio signals and their delays relative to the local time scale. Reliable determination of coordinates requires simultaneous stable reception of signals from several spacecraft, the number of which should be no less than the number of simultaneously determined orthogonal parameters, which is usually four or more.

The disadvantage of the considered systems for determining and tracking the location of moving objects using GNSS signals is the need to use sophisticated avionics that correlates the signals received from the satellite, as well as the discreteness of receiving data on the coordinates of the positioning object at the checkpoint, which can be critical for highly dynamic objects for implementation of tracking.

Known systems for determining and tracking the location of moving objects by GNSS signals, in which the signals received from a satellite are received at a positioning object, are relayed to a ground-based measuring station (NPC), where they determine the current coordinates of the object, see, for example, patent [4 ] - EP 0508405 A1, G01S 5/14, G07C 5/00, G07C 5/08, 10/14/1992. The advantage of such systems is the transfer of signal processing and navigation computing procedures to the NPC, which allows to significantly simplify and reduce the cost of on-board equipment of the positioning object. These properties are especially important when using these devices on non-returnable, often-run types of objects, because allow you to make a certain contribution to reducing costs when performing tasks solved by these objects.

Among the systems of this type are known systems in which the NPC has an additional receiving channel connecting it to the NKA, see, for example, patents: [5] - US 5119102, H04B 7/185, G01S 5/02, 02.06.1992; [6] - US 5225842, H04B 7/185, G01S 5/02, 02/02/1992. The presence of such an additional receiving channel allows faster and more accurate navigation calculations, in particular, through the use of service information obtained directly from the satellite (as provided in [5]), as well as through the implementation of a local differential mode (as provided at 6]).

The specified additional receiving channel connecting the NPC with the NSC is available in the adopted as a prototype system for determining the location of an object using GNSS signals described in the patent [7] - US 5379224, G01S 5/02, 01/03/1995, which implements a local differential mode.

The prototype system contains a space segment in the form of a GPS satellite, a relay located on a moving object, receiving and transmitting satellite signals, and a ground segment in the form of a NPC that receives relay signals and satellite signals.

The repeater contains serially connected receiver of signals of the NKA, the converter of the carrier frequency and the transmitter of the relay signals.

The NPC contains a block for receiving and processing signals from a repeater, as well as a series-connected block for receiving and processing signals from a satellite, a correction block, and a block for calculating coordinates of the location of a relay, the information input of which is connected to the output of a block for receiving and processing signals from a relay.

The work of the prototype system is as follows. NKA emit navigation radio signals, which are received by the NPC and the repeater. The repeater converts the carrier frequency of the received navigation radio signals and re-broadcasts them using the transmitter of the relay signals. Repeater signals are received at the NPC, where the pseudorange between the repeater and the satellite is determined using the unit for receiving and processing signals from the repeater. The pseudorange values between the repeater and the satellite are transmitted to the information input of the repeater location coordinate calculation unit, where the position of the repeater is determined by solving a system of equations based on the measured pseudorange and calculated coordinates of the satellite. The position of the repeater determined in this way can be clarified using the corrections obtained in the correction unit. To do this, using the block of reception and processing of signals from the spacecraft, the radio navigation signals coming directly from the spacecraft are received at the NPC, and the pseudorange between the NPC and the satellite is measured. At the same time, the distances between them are calculated using the a priori known coordinates of the NPC and the spacecraft. The result of comparing the measured and calculated values of the distances between the NPC and the NSC is the differential corrections that allow you to adjust the pseudorange measurements between the repeater and the NSC coming into the block for calculating the coordinates of the relay location. To a certain extent, this reduces the influence of the propagation conditions of navigation radio signals, the ephemeris and time errors of GNSS, increasing the accuracy of calculating the coordinates of the repeater due to the implementation of the local differential mode.

The disadvantage of the prototype system is the limited area of navigation service of the object with the accuracy implemented by the differential mode, which is especially typical for cases where the object’s trajectory (repeater trajectory) passes at high altitudes from the NPC, for example, through the ionospheric atmosphere, where the propagation conditions NKA navigation radio signals to the relay radically differ from the propagation conditions of the same signals to the NPC.

The technical result to which the utility model is directed is the creation of a system for determining the location of a moving object using GNSS signals, in which for any trajectories of the object (the trajectories of the repeater) there are no restrictions on the navigation service area of the object with the accuracy realized by the differential mode in conditions of radio communication in direction from repeater to NPC.

The essence of the utility model is as follows. The system for determining the location of a moving object by GNSS signals contains a space segment in the form of a satellite, a relay located on a moving object, receiving signals from a satellite and relaying them, and a ground segment in the form of a NPC receiving signals from a satellite and a relay. The repeater contains a serially connected receiver of signals from a satellite, a carrier frequency converter and a transmitter of relay signals, and the NPC contains a series-connected block from which to receive and process signals from a satellite, a correction block, and a block to calculate the coordinates of the location of the relay, the information input of which is connected to the output of the block for receiving and processing signals from the relay. At the same time, the correction block contains a block for calculating the ionospheric delay and a block for calculating the error of the ephemeris-time support (EVO) of the satellite, the first inputs of which, correspondingly, the first and second inputs of the correction block, are connected with the output of the block for receiving and processing signals of the satellite, and the outputs, forming, respectively, the first and second outputs of the correction unit are associated with the first and second correcting inputs of the unit for calculating the coordinates of the location of the repeater. The second input of the unit for calculating the error of the EVO NKA is connected with the output of the meteorological data block. The second input of the ionospheric delay calculation unit is connected with the output of the ionosphere data block, and the third input is connected with the output of the repeater position prediction unit, the input of which, forming the third input of the correction unit, is connected with the output of the repeater signal reception and processing block.

The essence of the utility model and its feasibility are illustrated by illustrative materials presented in figures 1-3, where:

figure 1 presents the structural diagram of the inventive system;

figure 2 is a conditional example of a model of the ionosphere, a horizontal slice;

figure 3 is a conditional example of a model of the ionosphere, a vertical slice.

The inventive system in the considered exemplary embodiment (Fig. 1) contains a space segment representing a constellation of the spacecraft 1 emitting navigation radio signals in the frequency ranges L1 and L2, a ground segment in the form of a NPC 2, and also a relay 3 located at the positioning object - a highly dynamic flying apparatus, the trajectory of which passes through the ionospheric layer of the atmosphere.

The relay 3 contains a series-connected receiver 4 of the NCA signals, designed to receive navigation radio signals in the frequency range L1, a carrier frequency converter 5 and a transmitter 6 of relayed signals, designed to transmit relay signals of the NCA 1 in the UHF band.

NPC 2 contains a repeater signal reception and processing unit 7, the input of which, formed by the corresponding receiving antenna, is connected by the radio channel to the repeater 3, and the output is connected to the information input of the repeater location coordinate calculation unit 8, the output of which is the information output of the system. The NPC 2 also includes a unit 9 for receiving and processing NKA signals, the input of which, formed by the corresponding receiving antenna, is connected by radio channels to those in the radio-visibility zone of the NKA 1, and the output through the block 10 is connected to the corresponding correcting inputs of the unit 8 for calculating the coordinates of the relay location.

The correction block 10 comprises a block 11 for calculating the ionospheric delay and a block 12 for calculating the error of the EVO of the satellite, the first inputs of which, respectively, forming the first and second inputs of the block 10 of the correction, are connected with the output of the block 9 for receiving and processing the signals of the satellite. The second input of the ionospheric delay calculation unit 11 is connected to the output of the ionosphere data unit 13, and the third input is connected to the output of the relay position pre-calculation unit 14, the input of which, forming the third input of the correction unit 10, is connected to the output of the relay signal reception and processing unit 7. The output of the ionospheric delay calculation unit 11, forming the first output of the correction unit 10, is connected to the first correcting input of the repeater location coordinate calculation unit 8. The second input of the block 12 for calculating the error of the EVO NKA is connected with the output of the block 15 of weather data. The output of the error calculation unit 12 of the EVA NKA, forming the second output of the correction unit 10, is connected with the second correcting input of the relay position calculation unit 8 of the repeater.

The system is as follows.

NKA 1 emit navigation radio signals in the frequency ranges L1 and L2.

Repeater 3 with the help of receiver 4 signals NKA carries out navigation radio signals from NKA 1, located in the radio visibility zone of relay 3 (at least four NKA), in the frequency range L1. Received navigation radio signals are frequency-converted using a carrier frequency converter 5 and re-emitted by a relay transmitter 6 in the UHF band.

Relay signals are received at NPC 2 using a repeater signal reception and processing unit 7, which correlates the received signals and measures the pseudorange of relay 3 with respect to each i-th satellite 1 located in the radio visibility zone (D ^P _meas .). The processing results — the values of the pseudorange of the relay 3 to each of the satellite 1 located in the radio-visibility zone of the relay 3 — are received in the form of digital signals to the information input of the repeater 8 coordinates of the location of the relay, and also to the input of the block 14 for calculating the position of the relay, which is part of the block 10 corrections.

At the same time, the navigation radio signals from the satellite 1, located in the radio visibility zone of the NIN 2, of both frequency ranges L1 and L2 are received on the NPC 2 using the block 9 of the reception and processing of the NSC signals, which performs correlation processing of the received signals, phase measurements and measurements of the pseudorange NPC 2 relative to each i-th satellite 1, located in the radio visibility zone of NPC 2 (D ^Н _ISM ), and also calculates the zenith distances z of these satellite 1.

From the output of the block 9 of the reception and processing of the NKA signals, the data on phase measurements, pseudo-range measurements and zenith distances z _i in the form of corresponding digital signals are input to the block 11 for calculating the ionospheric delay, where the following computational operations are carried out to determine the delay in the propagation of the navigation radio signal along the “ NKA-relay ”, due to the influence of the ionosphere, as well as its rate of change:

1. The integrated electron concentration (total electron content - TEC _i ) and the rate of its change (dTEC _i ) along the NKA-NIP path are calculated for all i-NKA 1 located in the radio visibility zone of NIP 2:

where A = (1 / β) · (f _L1 · f _L2 ) ² / (f _L1 ² -f _L2 ² ) - constant (its own for each GNSS);

β≈40,308 m ³ / s ² ;

ΔФ = Ф (t _{k + 1} ) -Ф (t _k ) is the increment of phase measurements in the interval Δt;

Δt = t _{k + 1} -t _k is the discrete pseudo-rangefinder and phase measurements (time interval between the current (t _{k + 1} ) and previous (t _k ) epochs of measurements);

Δτ _2/1 is the offset of the radiated navigation radio signal of the L2 range relative to the navigation radio signal of the L1 range, calculated as:

where ISC _{L1C / A} | _GPS , ISC _L2C | _GPS , Δτ _n - corresponding corrections, which are transmitted in frames of digital information GNSS GPS and GLONASS.

2. The calculation of the values of the vertical components of the integrated electron concentration TVEC _n and its rate of change dTVEC _n corresponding to the location of the NPC 2:

Where:

- i - number (index) of NKA 1;

- n - the number of NCA 1 located in the radio visibility zone of NPC 2 at the current time;

- z _i is the zenith distance of the i-th spacecraft 1;

- B (z _i ) = {1- [R _E / (R _E + h _m )] ² · sin ² z _i } ^1/2 ;

- R _E is the average radius of the Earth;

- h _m - the average value of the height of the ionosphere.

3. The values of the vertical components of the integrated electron concentration TVEC _p and its rate of change dTVEC _p corresponding to the current position of the repeater are determined 3. For this, data taken from the output of the unit 14 for calculating the position of the repeater and information on the state of the ionosphere obtained from the output of the unit 13 are used. The ionosphere model used for these purposes can be figuratively presented in the form of horizontal and vertical slices corresponding to fixed time instants. A horizontal section of the ionospheric model (Fig. 2) is characterized by a reference (coordinate) grid with known values of the vertical components of the integrated electron concentration of TVEC at its nodal points. The vertical section of the ionospheric model (Fig. 3) describes the electron concentration (n _e ) in the corresponding altitude layer of the ionosphere (h). Bringing these data (by interpolation) to the location of NPC 2 at the time of measurement and comparing them with the calculated values of TVEC _n and dTVEC _n allows us to evaluate the adequacy of the model to real conditions and, if necessary, adjust its parameters. Further, using the specified model and the calculated coordinates of the relay 3, the values of TVEC _p and dTVEC _{p are} determined for the current position of the relay 3.

4. The ionospheric delay is calculated. along the “NKA-relay” route for each i-th HKA 1 located in the radio-visibility zone of the relay 3, and its rate of change :

The mathematical relationships given in formulas (1) to (7) are determined by well-known relations (see, for example, [8] - Schaer S. Mapping and Predicting the Earth's Ionosphere Using the Global Positioning System // Ph. D. Dissertation, Astronomical Institute of the University of Bern, Switzerland, 1999; [9] - Akim E.L., Tuchin D.A. Ionospheric component of pseudorange measurements of near-Earth spacecraft / RAS.M. Keldysh Institute of Applied Mathematics // M. , Preprint, 04/04/2004).

Thus obtained values of the delay in the propagation of the navigation radio signal due to the influence of the ionosphere on the NKA-relay route, as well as the speed of its change in the form of corresponding digital signals, are received from the output of the ionospheric delay calculation unit 11 to the first correcting input of the relay location coordinate calculation unit 8.

At the same time, from the output of the HKA signal reception and processing unit 9, data on the measured pseudorange values (D ^H _meas ) and zenith distances z _i are received in the form of digital signals to the input of the HKA EVA error calculation unit 12, where the following computational operations are performed:

1. Based on a priori known coordinates of NPC 2, for each moment of time, the calculated (D ^H _calculation ) distance from NPC 2 to each i-th HKA 1 located in the radio visibility zone of NPC 2 is _determined , compared with the measured (D ^H _meas ) pseudorange and for each from these HKA 1 the total error of pseudorange measurement is calculated expressed in time equivalent and reduced to the frequency of the signal f _L1 in the range L1:

where: c is the speed of light.

At the same time, by differentiation, the rate of change of this error is estimated:

2. The ionospheric component Δ _{ui of the} measurement error of the pseudorange along the NKA-NIP path using the two-frequency method is calculated:

where: D ^H _measi (f _L1 ) is the measured pseudo range at the signal frequency f _L1 in the range L1;

D ^H _measi (f _L2 ) - measured pseudorange at the signal frequency f _L2 in the range L2.

At the same time, by differentiation, the rate of change of this error is estimated:

3. The tropospheric component Δ _{mp of the} measurement error of the pseudorange along the NKA-NIP highway is calculated using the troposphere model and the current values of temperature, pressure and humidity of the atmospheric air coming from the output of meteorological unit 15:

where: T is the temperature ([K]);

p is the atmospheric pressure ([mbar]);

e - partial pressure of water vapor ([mbar]), characterizing the humidity of the air;

z _i is the zenith distance of the i-th spacecraft 1;

In and δR - correction factors that determine the specificity of the location of NIN 2.

At the same time, by differentiation, the rate of change of this error is estimated:

4. The calculation of the error of the EVO NKA and the rate of change of this error in accordance with the expressions:

The thus calculated values of the error of the EVO of the spacecraft and the speed of its change in the form of corresponding digital signals are fed to the second correcting input of the relay position calculation unit 8 of the relay.

Thus, the following information and correction signals are received at the inputs of the unit 8 for calculating the coordinates of the relay location:

- to the information input from the output of the block 7 of the reception and processing of the signals of the relay received measured values of the pseudorange D ^P _meas ,

- the first correcting input from the output of the block 11 calculating the ionospheric delay receives the delay value of the radio signal due to the influence of the ionosphere on the NKA-relay, and its rate of change ,

- to the second correcting input from the output of the unit 12 for calculating the error of the EVA NKA and its rate of change .

In block 8 of the calculation of the coordinates of the location of the repeater, the following computational operations are performed:

1. The total corrective corrections are calculated. to the measured pseudo-ranges to each i-th NSS 1 located in the visibility range of the relay 3, as the algebraic sum of the terms:

where: t ₀ - time point for the formation of amendments;

t is the current time.

2. The measured values of the pseudorange up to each i-SCA 1 are corrected as the algebraic sum of the terms:

3. The coordinates of the repeater 3 are calculated by solving a system of equations with four unknowns (x, y, z, Δt ^' ), using the corrected values of ^{P P} _and pseudo- _ranges up to four or more of the satellite 1:

where: i is the number of the NCA 1 (i≥4);

D _i is the true geometric distance from the repeater to the i-th spacecraft 1;

x _HKAi , for _HKAi , z _HKAi - coordinates of i-NKA 1;

x, y, z - coordinates of the relay 3;

Δt ^' - the mismatch of the time scales of the NCA 1 and NPC 2;

c is the speed of light.

The mathematical dependences given in formulas (8) ÷ (18) are determined by well-known relations (see, for example, [10] - GLONASS. Principles of construction and functioning / Edited by A.I. Perov, V.N. Kharisov. // M., Radio Engineering, 2010, p.272-304, 440-452).

The coordinates of the positioning object (coordinates of the relay 3) obtained as a result of solving the system of equations are removed from the output of the block 8 for calculating the coordinates of the location of the relay, which forms the information output of the system.

Thus, in the claimed system, high-precision (due to the implemented differential mode) positioning of the positioning object is performed - the aircraft, the trajectory of which passes at high altitudes from NPC 2 through the ionospheric layer of the atmosphere, where the propagation conditions of navigation radio signals from NSC 1 to located on the positioning object of the relay 3 radically differ from the propagation conditions of the same signals from the NKA 1 to NPC 2.

The above shows that the claimed utility model is feasible and gives a technical result, which consists in creating a system for determining the location of a moving object using GNSS signals, in which, for any trajectories of an object carrying a relay 3, there are no restrictions on the navigation service area of the object with a differential accuracy of radio communication conditions in the direction from repeater 3 to NPC 2.

Information sources

1. EP 0509775 A2, G01S 19/42, G01S 5/00, G01S 5/14, publ. 10/21/1992.

2. US 5025261, H04B 7/185, G01S 5/02, publ. 06/18/1991.

3. US 5644317, G01S 5/02, G01S 3/02, G01C 21/00, publ. 07/01/1997.

4. EP 0508405 A1, G01S 5/14, G07C 5/00, G07C 5/08, publ. 10/14/1992.

5. US 5119102, H04B 7/185, G01S 5/02, publ. 06/02/1992.

6. US 5225842, H04B 7/185, G01S 5/02, publ. 06/02/1992.

7. US 5379224, G01S 5/02, publ. 01/03/1995.

8. International GPS Service. Information and Resources / IGS Central Bureau, 2001.

9. Schaer S. Mapping and Predicting the Earth's Ionosphere Using the Global Positioning System // Ph. D. Dissertation, Astronomical Institute of the University of Bern, Switzerland, 1999.

10. Akim E.L., Tuchin D.A. Ionospheric component of pseudorange measurements of near-Earth spacecraft / RAS. Institute of Applied Mathematics M.V. Keldysh // M., Preprint, 04.04.2004.

11. GLONASS. The principles of construction and operation / Ed. A.I. Perova, V.N.Kharisova. // M., Radio Engineering, 2010, p.272-304, 440-452.

Claims (1)

A system for determining the location of a moving object by signals from global navigation satellite systems, containing a space segment in the form of navigation spacecraft (NSC), a relay located on a moving object, receiving signals from the NSC and relaying them, and a ground segment in the form of a ground measuring station (NPC) receiving the signals of the NKA and the repeater, while the repeater contains a series-connected receiver of the signals of the NKA, the carrier frequency converter and the relay transmitter signals, and the NPC contains a serially connected unit for receiving and processing signals of the NSC, a correction unit and a unit for calculating coordinates of the location of the repeater, the signal input of which is connected to the output of the unit for receiving and processing signals of the repeater, characterized in that the correction unit contains a unit for calculating the ionospheric delay and a unit calculation of the error of the ephemeris-time support (EVO) of the spacecraft, the first inputs of which, respectively, forming the first and second inputs of the correction block, are connected with the output of the reception and processing the NKA signals, and the outputs forming the first and second outputs of the correction unit, respectively, are connected to the first and second correcting inputs of the repeater location coordinate calculation unit, while the second input of the EVA error calculation unit of the NKA is connected to the output of the meteorological data block, the second input of the ionospheric calculation unit the delay is associated with the output of the ionosphere data block, and the third input of the ionospheric delay calculation block is connected with the output of the repeater position prediction block, the input of which, forming the third input of the correction block is connected with the output of the block of reception and processing of the signal of the repeater.