How autonomous reduce the limits of detection and tracking of carrier signals received on the orbit
(57) Abstract:The invention relates to a method of Autonomous lowering the limits of detection and tracking of bearing taken on orbit receiver equipped with orbital navigation system, inside or outside the specified receiver, the latter has at least one ring phase-locked loop. Through this ring phase-locked loop detect and/or track the carrier, enter the exact auxiliary data about the speed and eliminate the error between the actual speed and the calculated speed. Search Doppler frequency carrier adopted carried out in the vicinity of the predicted value of the frequency obtained by using the exact auxiliary data about the speed coming from orbiting navigation system. Achievable technical result is to increase the accuracy of detection. 2 C.p. f-crystals, 4 Il. The technical field
The invention relates to a method of Autonomous reduce the limits of detection and tracking of carrier signals received on the orbit.Prior art
The invention combines three main components, namely the receiver, Borja data on radial velocities. Each of these three components will be discussed below.The receiver can be arbitrary used on satellites( ,  ,). Received signals may be transmitted by other satellites in orbit, or from fixed points on the earth's surface.As examples can be given the following types of receivers:
- GPS, GLONASS, GNSS1, GNSS2;
- narrowband receiver DORIS.Navigation systems GPS and GLONASS described in documents  and , respectively.GNSS1 is a placed in a geostationary orbit addition of GPS and/or GLONASS, using the navigation equipment installed on satellites, the Inmarsat-3, GNSS2 is a promising "civil" a constellation of navigation satellites.Narrowband receiver DORIS is used as the system global positioning and navigation by the CNES (national center navigation). The signals transmitted in the system are narrowband signals.DORIS NG is a project of global positioning and navigation in space, which establishes the nicknames in orbit.The filter determine the orbital parameters established on the basis of the digital processor placed, for example, in the receiver. It uses approximate measurements made by the receiver, i.e., measuring pseudokarst relative to the radiation source signal (on earth or in orbit). These measurements, though not necessarily, may be supplemented by measurements of pseudorange performed by using the modulation of the received carrier. The data measured for the Autonomous determination of the orbital parameters and/or location and velocity of the satellite carrier. The definition of these measurements is presented in . As the filter can be used:
- Kalman filter ;
- the simplest filter approximation by the method of least squares;
- recursive filter approximation by the method of least squares.This filter can also define the following parameters:
V1= D1= radial velocity between the satellite and i-m emitter,
Ti= relative temporal mismatch between the standard time of the i-th transmitter and the standard time of the receiver.Thus, the filter can estimate pseudokarst PVi< / BR>PVi< i-th oscillator, not processed by the receiver and installed the filter, due to the fact that the data on the location, speed and time coefficients of the specified emitter can be estimated or known in advance. Orbital navigation system determines these pseudokarst with precision PV.Orbital navigation system can receive remote control signals describing the maneuvers of the satellite carrier. These maneuvers can be described by the parameters Vx(t0); Vy(t0) and Vz(t0), where Virepresents the components of the speed pulse at time t0.Maneuvers of the satellite can be described with an accuracy given by the parameters VxVyVzin the three-axis coordinate system. The overall accuracy of the description of the maneuver V is defined as
< / BR>The procedure of reducing the threshold by clarifying data on radial velocity or radial pseudokarst applicable to receivers having one or more rings of the phase-locked loop. It is believed that these rings are locked loop are based on digital technology.When the signal is accepted with the ratio signal/noise S/Nobelow the threshold of detection or synchronization required igaly, containing the external data obtained on the basis of the predictions of the radial velocity or pseudokarst. Normal detection in the tracking mode is illustrated in .These predicted values of velocity must be sufficiently accurate and come from the sensor separately from the receiver. For example, the sensor may be an inertial type.This procedure can also be used to track the carrier signals of the GPS system with low equivalent ratio of C/Notaken by the radio system, GPS, and radios associated with the inertial devices and using these receivers speed is maintained with high precision.The invention relates to a method of Autonomous lowering the limits of detection and tracking of carrier signals received on the orbit.Summary of the invention
The invention relates to a method of Autonomous lowering the limits of detection and tracking of carrier signals received on-orbit receiver associated with the integrated orbital navigation system, inside or outside a specified receiver, characterized in that priemlemoe" auxiliary data about the speed and eliminating the difference between the real and the computed pseudocerastes, moreover, the search for the Doppler shift of the received carrier is in the vicinity of the predicted value of the frequency obtained using the updated auxiliary data about the speed coming from the navigation system.The method according to the invention includes the following steps:
the receiver serves auxiliary data necessary to detect with conventional auxiliary data, so the receiver receives all the signals, the ratio C/Nowhich is such that C/No> C/No)awhere (C/No)athe threshold carrier is detected in the mode detection with conventional auxiliary data;
the thresholds of the bearing is reduced to values of (C/No)avfwhere (S/No)avfthe detection threshold of the bearing in the discovery mode, which uses the auxiliary velocity data received from orbiting navigation system.The method may have a preliminary phase in which when you turn on the unit you lack any internal or external auxiliary data is carried out and the detection of signals with respect TO/Nosuch that/No>(S/No)nawhere (C/No)nathe threshold table is P> When conducting maneuvers to correct the orbit, orbital navigation system retrieves a description of the listed maneuvers and accordingly updates the auxiliary velocity data received from the navigation system. To ensure that the implementation of such a maneuver could be found bearing taken with a low ratio of C/Noin the first place should be the following condition is fulfilled:
where PV is the uncertainty in the prediction of pseudokarst received from the navigation system in the absence of a maneuver.V - the accuracy of the description of the maneuver,
In the analyzed frequency band,
fi- carrier frequency of the signal transmitted by the i-th emitter,
C is the speed of light.If the modulated information carrier is tracked with a ratio C/Nosuch that (S/Nabout)avf< S/No< C/No)aand demodulation of this information is impossible, the information on the characteristic parameters of the emitters can be transmitted to the receiver using signals from an external remote control.Proposed invention the method consists in lowering the limits of detection and otsluzhiv the parameters of the orbit. In accordance with the invention, this lower threshold is provided in standalone mode on-Board receivers. The specified lower threshold may be relatively large.Brief description of drawings
The invention is further illustrated by description of specific variants of embodiments with reference to the accompanying drawings, in which:
Fig. 1 illustrates a block diagram of the receiver with reduced threshold through the use of external auxiliary accurate data about the speed, according to the invention;
Fig. 2 illustrates a block diagram of the receiver with an integrated device according to the invention;
Fig.3 illustrates one embodiment of the invention;
Fig. 4 illustrates application of the invention for the receiver signals with spread spectrum, according to the invention.Description of the preferred variants of the invention
In Fig.1 shows a receiver for spread spectrum, with the threshold reduced through the use of external auxiliary accurate data about speed. Shown only the basic circuit elements of digital processing.The receiver 10 includes a high frequency unit 11, connected at least to about the alley includes a filter ring-locked loop 14 and the adder 15. The master oscillator (oscillator with digital control) 16 generates in-phase component of the local reference frequency Fi(and in some cases, and its quadrature component) for discriminator 13 and the generator input connected to the output of the adder 15. The discriminator 13 may contain detectory filter. The adder 15 through the switch 18 also receives signals from an external sensor and transmitter speed 17, for example, the inertial unit. The switch 18 is again turned on when the carrier recovery scheme 19 need external auxiliary accurate data about the speed for detection and/or tracking the received carriers.Tracking
The ring phase-locked loop, ensures retention of bearing, "pushed" auxiliary data speed. In other words, the master oscillator of the specified ring changes the phase of the local reference oscillations at a rate equal to the external prediction speed. Thus, the "boost" ring eliminates the difference between the real and calculated velocities.The order of the above rings should be relevant to the master oscillator was operated that will allow serenitatis, allows the detection of the carrier frequencies are also "pushed" auxiliary data speed. Search Doppler frequency accepted by the carrier, is in the neighborhood of the predicted value of the frequency (the exact preset frequency taking into account the Doppler shift), obtained using external velocity.The search range of the carrier frequency of the received signal is less than the detection mode with the usual supporting information. Thus, the principles described above is operable, if the uncertainty in the prediction of Doppler shift FDless than the analyzed area of the frequency range Century.Therefore, the uncertainty in the prediction of pseudokarst PV must meet the following ratios:
FD<B, i.e. PV = B/fiC,
where C is the speed of light,
fithe carrier frequency of the signal transmitted by the i-th emitter.Thus, since the uncertainty in the Doppler shift is smaller than in normal cases, the effective detection can be performed with a lower scan rate than under normal conditions at the same time So Therefore, the detection threshold is reduced.
(C/No)a- the capture threshold in detection mode when the normal auxiliary information;
(S/No)avfthe threshold of grip bearing in discovery mode using the exact auxiliary data speed. The definition of thresholds (C/Noand (S/No)adescribed in . Threshold (C/No)avfis a function of several parameters:
(C/No)avf= g(T; PV; B).
The invention has the following procedures performed in the receiver signals with spread spectrum, equipped with orbital navigation system.Step 1 (optional)
The receiver starts in the cold mode (in the absence of external and internal auxiliary data). In this case, it captures all the signals with a C/N ratiooso that:
C/No(S/No)na.Originally captured signals allow the receiver, though not necessarily, take messages, with which the receiver can determine the position and/or speed and/or temporary factors sources i, thereby ensuring convergence (convergence, tuning) orbital navigation system using the first measurement pseudokarst and the corresponding si is drugs.Stage 2
The receiver receives the auxiliary data needed to detection mode with the usual supporting information. This information is not very accurate and may be information of one of the following types:
1) date and time of the clock of the receiver;
2) position/velocity (or, though not necessarily, the orbital parameters of radiation sources;
3) position/velocity or orbital parameters of the satellite carrier.These data can be fully or partially received in step 1. In this case, they are in the receiver (e.g., position/velocity of the radiation sources can be transmitted by these sources). While retaining the possibility of Autonomous operation.When all or part of the above-mentioned approximate ancillary data received in the receiver by moving the external remote control operation is not fully Autonomous.When stage 1 is not met, these auxiliary data are necessarily outside of the receiver.These approximate auxiliary data allows the receiver to capture the signal with the C/N ratioothan described for stage 1, as:
(C/No)a< (S/Nabout)PA.It is assumed that the number of such measurements is sufficient to ensure such adjustment orbital navigation systems, in which the accuracy of the orbital parameters of the satellite carrier will be higher than in phase 1.Stage 3
After step 2 is performed, it is believed that the accuracy of the output parameters orbital navigation systems and characteristic parameters of the emitters corresponds to the quality of auxiliary data about the speed necessary to further lower the threshold for seizure of the bearing to the value of (C/No)avf.In contrast to previously known methods, the exact auxiliary velocity data received from orbiting navigation system built into the receiver.Therefore, the accuracy of the navigation system can be improved. In addition, in case of worsening conditions the signals from the radiation sources, deterioration of accuracy may be limited so as to ensure the fulfillment of the condition:
(C/No)avf< C/No)a.Stage 4
In the event of a maneuver to correct the orbit of the satellite, arcaroli, issued by the navigation system.To guarantee capture of pseudo-random code sequences taken when performing maneuvers with a low ratio of C/Nofirst of all must be fulfilled the following condition:
where PV is predicted navigation system is pseudokarst in the absence of a maneuver, V - accuracy of description of the maneuver.Step 5
When a pseudo-random sequence is monitored by the ratio C/Noso that:
(C/No)avf< C/No< C/No)a< / BR>demodulation of the signal transmitted by the emitters, it is not always possible.In the latter case, the updated values of the characteristic parameters of the signal emitters (location and/or velocity and/or time factors) should be transferred to the receiver using an external remote control, if necessary. So, for example, receivers GPS or GLONASS, these parameters can be the ephemerides of the satellites used in the system.In Fig.2 shows a receiver 29 for a companion, having at least one high-frequency unit 30, the receiving signal and 32. Built-in navigation system 33 receives from the ring-locked loop information if (C/No) > (S/No)a. This navigation system provides accurate supporting data speed in the ring phase-locked loop. Built-in orbital navigation system receives a description of the maneuvers of the satellite and external data.In Fig.3 shows a variant embodiment in which the orbital navigation system 33 is embedded in the onboard computer 34, is placed on the satellite.In Fig.4 shows an example embodiment in which the receiver 29 provides a signal processing spread spectrum.In the receiver 29 is provided at least one ring phase-locked loop 32 and at least one ring-locked loop in the code sequence 35. The ring phase-locked loop includes a switch 19 located between the filter ring F(R) and the adder 15.Ring-locked loop in the code sequence contains the discriminator 36, the inlet of which a carrier, modulated adopted a pseudo-random codes coming from the high-frequency unit 11. This discriminator may contain detectory filter. Output DRA 37 and the reference frequency, proportional to the velocity generated by the master oscillator OS N 16. The specified output of the adder is connected to specifying the code generator 39, which in turn is connected to a reference generator local code 40.The generator 40 with one side connected to the correlator 41, giving him the common-mode reference code sequence, and on the other hand - to the discriminator 36, giving him a reference code sequence ahead and the reference code sequence with a delay. The discriminator 13 ring phase-locked loop connected to the correlator 41.Ring-locked loop code sequence 35 takes the exact auxiliary velocity data from the master oscillator OCN 16. The switch 18 is switched on if the ring-locked loop for carrier requires accurate supporting data rate coming from the built-in orbital navigation system 33, for use in tracking modes and/or seizure of the bearing.The switch 18 remains off, if the condition C/No< C/No)avf. In this case, ring-locked loop for carrier detect and accompanies the signal and the switch 18 is switched on. So obstime 33 in the ring-locked loop in the code sequence 35.Variants of use of the invention
The application of the method applies to cases receiving bearing Board the spacecraft at low energy balance in the radio link between the emitters and the above-mentioned satellites. The method in accordance with the invention can be used in the following cases.From the point of view of the types of receivers
Navigation using satellite navigation systems like GPS, GLONASS.Navigation using transceivers signals with spread spectrum. The energy characteristics of the communication line can be at the beginning and end of the span of the footprint of the control station and receive telemetry (TM/TC), or at the beginning and end of the passage the service area of the satellite-relay TDRSS.Navigation using narrowband receiver DORIS.Navigation using the receiver for spread spectrum transmitted by a group of ground-based radio beacons equipped with antenna systems with hemispherical directional diagrams. It is believed that the radiation power of these beacons is optimized for reception of signals of low-orbit satellites. Consequently the I less favorable.Positioning using signal receivers, satellite systems (like GPS, GLONASS) or using signals with spread spectrum transmitted by a group of ground-based radio beacons (like DORIS NG). The number of interferometric measurements using bearing taken with a ratio C/No> C/No)athat is not necessarily satisfactory when solving problems related to positioning. In certain cases it may be necessary detection and/or tracking of the bearing taken with a ratio C/No> (S/No)avf.For the orbits
Navigation using GPS or DORIS NG for some geostationary transient orbits, for example:
- conventional geostationary transition orbit (OTG);
- Versiliana orbit (OSPS);
- podsyhanija orbit (OSBS);
- drifting orbit (ODD).Navigation can be done using at least two antennas with a small gain, if the capture threshold signal is low (see /7/).Positioning using receivers on satellites on highly-elliptical orbits-type:
- orbit "Zip";
the traditional satellite systems, located on circular orbits with a period of about 12 hours, as receiving antennas are used terrestrial antenna with a hemispherical radiation pattern.Navigation using receivers on satellites in low-earth orbits, connected to one or more inexpensive reception antennas, which are not optimal, but good enough to ensure that the receiver phase 2 in accordance with the present invention.Sources of information
1. Orbital Navigation with a GPS Receiver on the HETE Spacecraft" (10N GPS, January 1994, S. 645-656).2. "ESA Dual-Standard S-Band Transponder: A Versatile TT&C Equipment for Communications via a Data Relay Satellite or Directly with the Ground Network" by J. L. Gerner (42nd Congress of the International Federation of astronauts, October 5-11, 1991).3. "Standardization Agreement: Characteristics of the global position determination system NAVSTAR (GPS)" (OTAN, STANAG 4294).4. "GLONASS Approaches Full Operational Capability (FOC)" by P. Daly (10N GPS, September 1995).5. Module 6 Space Vehicle Technologies and Procedures-space location; (Cepadues Editions).6. "Low-Orbit Navigation Concepts" by H. James Rome (vol 35, 3, 1988, S. 371-390).7. "GPS Techniques for Navigation of Geostationary Satellites" by P. Ferrage, J. L. Issler, G. Campan and J. C. Durand (10N GPS, 12-15 September 1995).8. "Applicability of GPS-Based Orbit Determination Systems to a Wide Range of HEO Missions" by J. Potti, P. Bernedo and A. Pasetti (10N GPS signals from radiation sources, taken on orbit receiver that has access to signals from orbiting navigation satellite system, characterized in that the receiver set at least one ring phase-locked loop frequency of the received signals, take the receiver signals with the ratio signal/noise S/Nowhen C/No> (S/No)nawhere the ratio (C/No)nais the capture threshold of the carrier frequencies of the signals of the radiation sources, in the absence of auxiliary data signal is accepted by the receiver signals the auxiliary data from orbital speed of the satellite navigation system and carry out the seizure signal ratio S/Nowhen C/No> (S/No)awhere the ratio (C/No)ais the capture threshold of the carrier frequencies of the signals of the radiation sources, detection mode using the auxiliary data signals, and (S/No)na> (S/No)athen use the ring phase-locked loop frequency of the received signal, which changes the phase of the local reference signal to correct the error between the actual and calculated orbital satellite navigation system pseudologia (S/No)a> (S/No)avfwhere (S/No)avf- the capture threshold of the carrier frequencies of the signals of the radiation sources in the discovery mode using the exact auxiliary data about the speed coming from orbiting navigation satellite systems, the specification of auxiliary data on the rate issued by the orbital satellite navigation system is provided
where PV is the forecasting error of the auxiliary data pseudokarst issued by the navigation system in the absence of the orbit control of satellites;
C is the speed of light;
fi- carrier frequency of the signal transmitted by the i-th radiation source;
In the analyzed frequency band.2. The method according to p. 1, characterized in that in the case of maneuver to control the orbit of a satellite orbiting navigation satellite system signal carrying the information about the speed specified maneuver, and update the auxiliary data rate issued by the satellite orbital navigation system, while fulfilling the following condition
where V is the accuracy of the maneuver of the satellite.3. The method according to p. 1, characterized in that parametrov radiation sources about the location, speed and temporal misalignment pass to a receiver using an external remote control.
FIELD: the invention refers to radio technique means of determination of a direction, location, measuring of distance and speed with using of spaced antennas and measuring of a phase shift or time lag of taking from them signals.
SUBSTANCE: the proposed mode of determination of coordinates of an unknown transmitter is based on the transmitter's emitting of a tracing signal to the satellite, on receiving of signals of an unknown transmitter and legimite transmitters which coordinates are known, on forming a file of clusters, on selection of the best clusters out of which virtual bases are formed for calculating coordinates of legimite and unknown transmitters according to the coordinates of legimite transmitters and the results of calculation of their coordinates one can calculate mistakes of measuring which are taken into account at calculating the coordinates of the unknown transmitter.
EFFECT: increases accuracy of determination of coordinates of an unknown transmitter in the system of a satellite communication with a relay station on a geostationary satellite.
2 dwg, 1 tbl
FIELD: aeronautical engineering; determination of aircraft-to-aircraft distance.
SUBSTANCE: aircraft-to-aircraft distance is determined by the following formula: where position of first of first aircraft is defined by azimuth α1, slant range d1, altitude h1 and position of second aircraft is determined by azimuth α2, slant range d2 and altitude h2. Proposed device includes aircraft azimuth indicators (1,4), flying altitude indicators (2,5), indicator of slant range to aircraft (3,6), adders (7, 14, 15, 19), multiplication units (8-12, 16, 18), cosine calculation unit 913), square root calculation units (17-20) and indicator (21).
EFFECT: avoidance of collision of aircraft; enhanced safety of flight due to determination of true aircraft-to-aircraft distance with altitude taken into account.
FIELD: radio engineering, applicable in receivers of signals of satellite radio navigational systems.
SUBSTANCE: the micromodule has a group of elements of the channel of the first frequency conversion signals, group of elements of the first channel of the second frequency conversion of signals, group of elements of signal condition of clock and heterodyne frequencies and a group of elements of the second channel of the second frequency conversion signals.
EFFECT: produced returned micromodule, providing simultaneous conversion of signals of standard accuracy of two systems within frequency ranges.
FIELD: railway transport.
SUBSTANCE: proposed repair team warning device contains "n" navigational satellites, dispatcher station consisting of receiving antenna, satellite signals receiver, computing unit to determine corrections to radio navigational parameter for signals from each navigational satellite, modulator, transmitter, transmitting antenna and computer of standard values of radio navigational parameters, movable object installed on locomotive and consisting of satellite signals receiving antenna, satellite signals receiver, computing unit for determining location of movable object, first receiving antenna, first receiver, first demodulator, matching unit, modulator, transmitter, transmitting antenna, second receiving antenna, second receiver and second demodulator, and warming device consisting of receiving antenna, receiver, demodulator, computing unit for determining distance between movable object, warning device, modulator, transmitter, transmitting antenna, satellite signals receiving antenna, satellite signals receiver and control unit.
EFFECT: improved safety of track maintenance and repair teams in wide zone of operation.
FIELD: the invention refers to navigational technique and may be used at designing complex navigational systems.
SUBSTANCE: an integrated satellite inertial-navigational system has a radioset connected through an amplifier with an antenna whose outputs are connected to a computer of the position of navigational satellites and whose inputs are connected with the block of initial installation of the almanac of data about satellites' orbits. The outputs of this computer are connected with the inputs of the block of separation of radio transmitting satellites. The outputs of this block are connected with the first group of inputs of the block of separation of a working constellation of satellites whose outputs are connected with inputs of the block of computation of a user's position. The system has also a meter of projections of absolute angle speed and a meter of projections of the vector of seeming acceleration which are correspondingly connected through a corrector of an angle speed and a corrector of seeming acceleration with the first group of inputs of the computer of navigational parameters whose outputs are connected with the first group of the outputs of the system. The system also includes a computer of initial data which is connected with three groups of inputs correspondingly to the outputs of the meter of projections of absolute angle speed and the meter of projections of a vector of seeming acceleration and to the outputs of a block of integration of information and also to the outputs of the block of computation of a user's position. At that part of the outputs of the computer of initial data are connected to the inputs of the computer of navigational parameters and all outputs are connected to the first group of the inputs of the block of integration of information whose second group of inputs is connected with the outputs of the corrector of an angle speed and the corrector of seeming acceleration, and the third group of inputs is connected to the outputs of the block of computation of a user's position. One group of the outputs of the block of integration of information is connected to the second group of the inputs of the block of selection of a working constellation of satellites, the other group of the outputs are directly connected to the second group of the outputs of the system, the third group of the outputs are connected to the inputs of the corrector of seeming acceleration and the fourth group of the outputs are connected with the inputs of the corrector of an angle speed and the second group of the inputs of the computer of initial data.
EFFECT: increases autonomous of the system, expands composition of forming signals, increases accuracy.
FIELD: satellite radio navigation, geodesy, communication, applicable for independent instantaneous determination by users of the values of location co-ordinates, velocity vector components of the antenna phase centers of the user equipment, angular orientation in space and bearing.
SUBSTANCE: the method differs from the known one by the fact that the navigational information on the position of the antenna phase centers of ground radio beacons, information for introduction of frequency and time corrections are recorded in storages of the user navigational equipment at its manufacture, that the navigational equipment installed on satellites receives navigational radio signals from two and more ground radio beacons, and the user navigational equipment receives retransmitted signals from two satellites.
EFFECT: high precision of navigational determinations is determined by the use of phase measurements of the range increments according to the carrier frequencies of radio signals retransmitted by satellites.
3 dwg, 1 tbl
FIELD: radio communication.
SUBSTANCE: in accordance with the invention, the device for radio communication provides for getting of first time base (for example, getting of the code time shift) from the signal received from the transmitter on the ground. The predetermined shift based at least on the delay of propagation of received signal is applied to the first time base for obtaining of the second time base. For example, the second time base may be equalized with the time base of the satellite system of position finding (for example, GPS NAVSTAR).
EFFECT: synchronizing signal is generated, with has a time code shift based on the second time base.
6 cl, 12 dwg
FIELD: aviation engineering.
SUBSTANCE: device has on-ground automated system for controlling air traffic made in a special way, interrogation unit and re-translator mounted on air vehicles and made in a special manner as well. Autonomous duplication is used for measuring distance between flying vehicles.
EFFECT: widened functional abilities.
FIELD: radio navigation aids, applicable in digital correlators of receivers of satellite radio navigation system (SPNS) signals, in particular, in digital correlators of receivers of the SPNS GLONASS (Russia) and GPS (USA) signals.
SUBSTANCE: the legitimate signal in the digital correlator is detected by the hardware, which makes it possible to relieve the load of the processor and use its released resources for solution of additional problems. The digital correlator has a commutator of the SPNS signals, processor, digital mixers, digital controllable carrier-frequency oscillator, units of digital demodulators, accumulating units, programmed delay line, control register, digital controllable code generator, reference code generator and a signal detector. The signal detector is made in the form of a square-law detector realizing the algorithm of computation of five points of the Fourier sixteen point discrete transformation with additional zeroes in the interval of one period of the, c/a code with a subsequent computation of the modules of the transformation results and their incoherent summation and comparison with a variable threshold, whose value is set up depending on the noise power and the number of the incoherent readout. The signal detector has a controller, multiplexer, complex mixer, coherent summation unit, module computation unit, incoherent summation unit, noise power estimation unit, signal presence estimation unit and a unit for determination of the frequency-time coordinates of the global maximum.
EFFECT: provided acceleration of the search and detection of signals.
2 cl, 6 dwg
FIELD: submarine, marine terrestrial and close-to-ground navigation, in particular type GPS and GLONASS systems.
SUBSTANCE: at a time instant, that is unknown for the receiver, a signal is synchronously radiated by several radiators with known co-ordinates. The radiated signals are received by the receiver, the signal speed square is measured in the current navigation session, the Cartesian co-ordinates of the receiver are computed according to the moments of reception of the radiated signal and the measured signal speed square.
EFFECT: enhanced precision of location of the signal receiver.