CN113272671A - Aircraft guidance using two antennas with different opening angles - Google Patents
Aircraft guidance using two antennas with different opening angles Download PDFInfo
- Publication number
- CN113272671A CN113272671A CN201980074200.2A CN201980074200A CN113272671A CN 113272671 A CN113272671 A CN 113272671A CN 201980074200 A CN201980074200 A CN 201980074200A CN 113272671 A CN113272671 A CN 113272671A
- Authority
- CN
- China
- Prior art keywords
- antenna
- aircraft
- power
- deviation
- signal received
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000034 method Methods 0.000 claims description 24
- 238000005259 measurement Methods 0.000 claims description 11
- 238000006073 displacement reaction Methods 0.000 claims description 10
- 230000000737 periodic effect Effects 0.000 claims description 3
- 238000012937 correction Methods 0.000 description 13
- 238000004364 calculation method Methods 0.000 description 6
- 238000004088 simulation Methods 0.000 description 6
- 238000004422 calculation algorithm Methods 0.000 description 5
- 238000012545 processing Methods 0.000 description 5
- 238000004891 communication Methods 0.000 description 4
- 238000001914 filtration Methods 0.000 description 4
- 230000005855 radiation Effects 0.000 description 4
- 230000001133 acceleration Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000003313 weakening effect Effects 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000012417 linear regression Methods 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 230000001360 synchronised effect Effects 0.000 description 2
- 230000001960 triggered effect Effects 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000013598 vector Substances 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S3/00—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received
- G01S3/02—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received using radio waves
- G01S3/14—Systems for determining direction or deviation from predetermined direction
- G01S3/28—Systems for determining direction or deviation from predetermined direction using amplitude comparison of signals derived simultaneously from receiving antennas or antenna systems having differently-oriented directivity characteristics
- G01S3/30—Systems for determining direction or deviation from predetermined direction using amplitude comparison of signals derived simultaneously from receiving antennas or antenna systems having differently-oriented directivity characteristics derived directly from separate directional systems
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S3/00—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received
- G01S3/02—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received using radio waves
- G01S3/14—Systems for determining direction or deviation from predetermined direction
- G01S3/28—Systems for determining direction or deviation from predetermined direction using amplitude comparison of signals derived simultaneously from receiving antennas or antenna systems having differently-oriented directivity characteristics
- G01S3/32—Systems for determining direction or deviation from predetermined direction using amplitude comparison of signals derived simultaneously from receiving antennas or antenna systems having differently-oriented directivity characteristics derived from different combinations of signals from separate antennas, e.g. comparing sum with difference
- G01S3/34—Systems for determining direction or deviation from predetermined direction using amplitude comparison of signals derived simultaneously from receiving antennas or antenna systems having differently-oriented directivity characteristics derived from different combinations of signals from separate antennas, e.g. comparing sum with difference the separate antennas comprising one directional antenna and one non-directional antenna, e.g. combination of loop and open antennas producing a reversed cardioid directivity characteristic
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
- G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
- G01S5/0257—Hybrid positioning
- G01S5/0263—Hybrid positioning by combining or switching between positions derived from two or more separate positioning systems
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D1/00—Control of position, course, altitude or attitude of land, water, air or space vehicles, e.g. using automatic pilots
- G05D1/02—Control of position or course in two dimensions
- G05D1/0202—Control of position or course in two dimensions specially adapted to aircraft
-
- G—PHYSICS
- G08—SIGNALLING
- G08G—TRAFFIC CONTROL SYSTEMS
- G08G5/00—Traffic control systems for aircraft, e.g. air-traffic control [ATC]
- G08G5/02—Automatic approach or landing aids, i.e. systems in which flight data of incoming planes are processed to provide landing data
- G08G5/025—Navigation or guidance aids
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q25/00—Antennas or antenna systems providing at least two radiating patterns
- H01Q25/002—Antennas or antenna systems providing at least two radiating patterns providing at least two patterns of different beamwidth; Variable beamwidth antennas
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
- H01Q3/02—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system using mechanical movement of antenna or antenna system as a whole
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Aviation & Aerospace Engineering (AREA)
- Automation & Control Theory (AREA)
- Variable-Direction Aerials And Aerial Arrays (AREA)
- Position Fixing By Use Of Radio Waves (AREA)
- Details Of Aerials (AREA)
Abstract
The invention relates to a guidance system (1) for an aircraft (A), comprising: -a first antenna (10) having a first opening angle (O1) of-3 dB, -a second antenna (20) having a second opening angle (O2) of-3 dB, the first opening angle (O1) being at least twice as large as the second opening angle (O2), the absolute value of the difference between the power of the signal received from the first antenna (10) and the power of the signal received from the second antenna (20) being at least equal to 10dB within the second opening angle (O2) of the second antenna (20).
Description
Technical Field
The present invention relates to the field of aircraft guidance, and more particularly to estimating the alignment of a determined orbit of an aircraft without the use of a satellite absolute positioning system.
Background
Guidance systems for existing aircraft, in particular for unmanned aircraft, enable autonomous guidance of the aircraft along a predetermined trajectory (corresponding for example to the journey of an observation mission). In order to perform this guidance, the position of the aircraft is determined at regular intervals and compared with the trajectory to be followed. The position is typically determined using a receiver of a satellite absolute positioning system, such as the GPS or galileo system.
However, it may happen that the computer of the aircraft cannot determine the current position of the aircraft, either due to a failure of a component of the aircraft, for example a GPS receiver, or due to the unavailability of signals of the positioning system (for example in the event of signals of the positioning system becoming cluttered). In this case, the computer is unable to guide the aircraft so that it follows a predetermined trajectory. Thus, the aircraft is at risk of collision and getting lost at unknown locations.
To avoid this, the current position of the aircraft may be determined using another system integrated on the aircraft, for example using an inertial unit to constantly measure the linear and angular accelerations of the aircraft. The integral of the signal provided by the inertial unit is then used to determine the displacement of the aircraft and thus its relative position with respect to the final position provided by the satellite positioning system. However, the uncertainty of the position determined in this way can be high. This is because the accumulation over time of the deviation between the movement determined by integration and the actual movement of the aircraft can produce a positional drift of the aircraft relative to its actual position. This drift may correspond to a flight of kilometers per hour from the last position provided by the satellite positioning system.
It has therefore been proposed that, in addition to this, data measured by an on-ground inclinometer can be used for correcting the position data provided by the inertial unit and deriving corrected position data from the position data provided by the inertial unit, which corrected position data compensates for the drift of the inertial unit. To this end, the deviation meter is connected to a directional antenna of a ground station configured to constantly measure the direction in which the aircraft is located relative to a reference direction (e.g. north). For more details of this system, the reader is specifically referred to patent document FR3033924 in the name of applicant.
However, this deviator is not system-usable.
Therefore, there is a need for a guidance method that enables an aircraft to be safely guided from a remote return point to an airport autonomously and to land on its runway, even if satellite positioning is not available, even if there is a significant drift in the current position of the aircraft determined based on signals from its inertial units.
Disclosure of Invention
It is an object of the present invention to propose an alternative to the use of an inclinometer on the ground, so as to be able to estimate the position of the aircraft and its landing simply and effectively, even if satellite positioning is not available or there is any drift in the current position of the aircraft.
To this end, the invention proposes a system for guiding an aircraft, comprising:
-a first antenna having a first half-power beamwidth,
-a second antenna having a second half-power beamwidth,
the system is characterized in that:
-the first beamwidth is at least twice the second beamwidth,
-the absolute value of the deviation between the power of the signal received from the first antenna and the power of the signal received from the second antenna is at least equal to 10dB within the second beamwidth of the second antenna.
Some preferred but non-limiting features of the guidance system, which can be used individually or in combination, are as follows:
-the first antenna is omnidirectional.
-the first antenna and the second antenna are coaxial.
-the first beam width is between 3 ° and 5 ° and the second beam width is between 0.5 ° and 1.5 °.
-the first antenna has a gain between 25dB and 35dB and the second antenna has a gain between 35dB and 50 dB.
-the first and second antennas move as a single component, and the system further comprises means for displacing the first and second antennas.
According to a second aspect, the invention proposes a method for autonomous guidance of an aircraft using a guidance system according to any one of claims 1 to 6, said method comprising the following steps:
s1: positioning a first antenna and/or a second antenna such that a boresight of the first antenna and/or the second antenna is aligned at an assumed position of an aircraft,
s2: measuring the power of a signal received by the first antenna,
s3: simultaneously, measuring the power of the signal received by the second antenna,
s4: determining a deviation between the power of the signal received by the first antenna and the power of the signal received by the second antenna,
s5: deriving any misalignment error between the line of sight of the first antenna and/or the second antenna (on the one hand) and the aircraft (on the other hand) based on the determined deviation.
Some preferred but non-limiting features of the guidance method that can be used individually or in combination are as follows:
-during steps S1 to S3, the first and second antennas are coaxial.
The method further comprises the following step before step S5:
s6: angularly shifting the first and second antennas by a plurality of beam steering angles, then repeating steps S2-S4 for each beam steering angle to determine a respective offset for each beam steering angle, an
S7: the maximum value of the deviation obtained is evaluated.
-during the shifting step S6, the first and second antennas perform an angular scan along an azimuth and/or a tilt angle in accordance with a periodic pattern.
-performing steps S6 and S7 only if the deviation determined based on the assumed position of the aircraft in step S5 is less than a determined threshold.
-the method further comprises: the following steps after step S7: positioning the first and second antennas such that the boresight of the first and second antennas is substantially aligned with a direction corresponding to the determined maximum of the deviation.
-during step S6, the beam steering angle is greater than or equal to the second beam width and less than or equal to twice the second beam width.
During step S7, the maximum of the deviations is estimated by a time-domain convolution method, or based on a second-order polynomial approximation of the measurements obtained in steps S2 and S3 and associating a given deviation with each beam steering angle.
Drawings
Other features, objects and advantages of the invention will become more apparent upon reading the following detailed description, with reference to the accompanying drawings given by way of non-limiting example, in which:
fig. 1 schematically shows a radiation diagram of an example of a first antenna and an example of a second antenna, both coaxial, that can be used in the guidance system of the invention.
Fig. 2 schematically shows a radiation diagram of another example of a first antenna and one example of a second antenna, both of which are coaxial, which can be used in a guidance system according to the invention.
Fig. 3 schematically shows a radiation diagram of another example of a first antenna and one example of a second antenna, both of which are coaxial, which can be used in a guidance system according to the invention.
Fig. 4 shows an example of a deviation measurement in dB between the power of the signal received by a first antenna and the power of the signal received by a second antenna, both coaxial, aligned on the same radio transmitter and able to be used in the guidance system of the invention, during a sinusoidal scan (in degrees) with respect to the pointing angle and during a second-order polynomial approximation of the measurement results.
Fig. 5 shows an example of the deviation between the power received by the first antenna and the power received by the second antenna for fig. 4, where the aircraft starts drifting at t-2000 s.
Fig. 6 to 8 show simulation results of a given example when triggering an angle measurement algorithm, fig. 6 showing the power of the signals received from the first antenna and from the second antenna, fig. 7 showing between the antennas as raw (dsirss) and as filtered (dsirss)Filtering) Fig. 8 shows the state of the goniometry algorithm (0 is the preparation phase after the filtering reset of the power offset, 1 is the filtering phase without correction calculation, 2 is the scanning and correction phase).
Fig. 9 very schematically shows an example of a system for guiding an aircraft according to an embodiment of the invention.
FIG. 10 is a flowchart of the steps of an exemplary embodiment of a method for guiding an aircraft according to the present invention.
Detailed Description
Embodiments of the present invention relate to a system 1 for an autonomously guided aircraft a, the system comprising two antennas 10, 20, the beamwidth of the antennas 10, 20 being selected as: it is possible to determine whether the aircraft a is in the desired direction by simply comparing the respective signal powers of the antennas 10, 20, or conversely, whether the aircraft a deviates from the desired direction and, where applicable, the direction of the aircraft a, which is actually found by iteration.
More precisely, the guidance system 1 comprises a first antenna 10 having a first half-power beamwidth O1 and a second antenna 20 having a second half-power beamwidth O2. The first beam width O1 is at least twice the second beam width O2, and the absolute value of the deviation (difference) between the power of the signal received from the first antenna 10 and the power of the signal received from the second antenna 20 within the second beam width O2 of the second antenna 20 is at least equal to 10 dB.
Therefore, the first antenna 10 has a wide beam width compared to the second antenna 20.
For example, the first beam width O1 may be between 3 ° and 5 °, typically on the order of 4 °, while the second beam width O2 may be between 0.5 ° and 1.5 °, typically on the order of 1 °.
Furthermore, the first antenna 10 may have a gain between 25dB and 35dB, for example in the order of 30dB, and the second antenna 20 has a gain between 35dB and 50dB, for example in the order of 40 dB.
The guidance system 1 is based on the principle that the aircraft a is a radio transmitter so that when the radio transmitter moves away from the receiver antenna, the power of the signal measured by the antenna decreases. However, it can be seen that when a single antenna is used, the weakening of the signal power measured by that antenna can also be attributed to a number of factors including increased distance between the aircraft a and the antenna, radio transmission problems, antenna power failure, weather conditions, shadowing (the presence of another radio transmitter between the aircraft a being guided and the antennas 10, 20), etc. This weakening of the signal does not therefore necessarily lead to a misalignment of the aircraft a with the line of sight of the antenna (i.e. the axis of symmetry of the main lobe of said antenna).
However, the deviation between the signal powers of two antennas 10, 20 aligned on the same radio transmitter remains constant regardless of the distance between the radio transmitter and the two antennas 10, 20. Thus, if the deviation between the signal powers measured by two given antennas 10, 20 is less than a given threshold or becomes weaker, this necessarily means that the aircraft a is not aligned with the antennas 10, 20.
The choice of an antenna 10 with a wide beam width and an antenna 20 with a narrow beam width makes it possible to obtain a power deviation sufficient to detect the misalignment of the aircraft a, and the difference between the gains of the two antennas 10, 20 is significant enough to make the measurement accuracy sufficient to guide the aircraft a. Furthermore, it is also necessary to enable sufficient angular scanning to be performed if a weakening of the power deviation is detected.
With particular reference to fig. 1, fig. 1 schematically shows a radiation pattern of an example of a first antenna 10 and an example of a second antenna 20, the first and second antennas being coaxial. The power deviation E1 is greatest when the radio transmitter is aligned with the axes X1, X2 of the antennas 10, 20 (aircraft a 1). On the other hand, when the radio transmitter is not aligned (aircraft a2), the power deviation E2 between the two antennas 10, 20 is low.
It should be appreciated that using the power offset to guide aircraft a allows the determination of the power offset to be independent of:
the distance between the aircraft a and the antennas 10, 20, provided that this distance remains less than a threshold detection limit;
a radio transmission;
power deficiency at the transmitter antenna;
weather conditions;
any shadowing;
and others.
In particular, in either case, the signal power received by each of the antennas 10, 20 is similarly attenuated, so that in each of the above cases the power deviation remains constant for the same position and the same alignment of the radio transmitter.
Preferably, the first antenna 10 and the second antenna 20 are coaxial to maximize the overlap between their beam width ranges. However, in one embodiment, the first antenna 10 and the second antenna 20 may be non-coaxial. In this case, the antennas 10, 20 are positioned such that the beam width of the first antenna 10 overlaps with the beam width of the second antenna 20 (see fig. 2), wherein the beam width of the first antenna 10 is wide.
Where applicable, the first antenna 10 with wide beamwidth O1 may be omni-directional. The second antenna 20, on the other hand, is directional and steerable (fig. 3).
The first antenna 10 and the second antenna 20 move as one part. The term "move as one part" will be understood herein to mean that the first antenna 10 and the second antenna 20 perform the same movement simultaneously. For this purpose, the first antenna 10 and the second antenna 20 may be firmly connected together using a clamping connection, or separated from each other, but displaced in a synchronized manner and according to the same action.
Furthermore, the guidance system 1 comprises a displacement device 2 for displacing the first and second antennas 20.
Preferably, the first antenna 10 and the second antenna 20 are displaced simultaneously by one and the same displacement device 2 or by two separate but synchronized displacement devices 2.
The displacement device 2 may for example comprise an antenna-carrying positioner 10, 20 configured to receive alignment instructions from the computer 6 (see below) and to execute said instructions.
The guidance system 1 may also comprise a plurality of positioning devices 3 configured to determine the assumed position of the aircraft a. These means 3 may comprise, for example, an inertial unit integrated on the aircraft a, configured to integrate the movements (acceleration and angular speed) of the aircraft a to estimate its azimuth (roll, pitch and heading), linear speed and position. To this end, the inertial unit 3 generally comprises accelerometers for measuring the linear accelerations of the aircraft a in three orthogonal directions, and gyroscopes for measuring the three components of the angular velocity vectors (roll, pitch and yaw). The inertial unit 3 also provides the attitude (roll, pitch and heading angle) of the aircraft a.
In a variant, the positioning means 3 may comprise a system for absolute positioning by means of satellites, for example the GPS or galileo system.
Finally, the guidance system 1 comprises a system 4 and data processing devices 5, 6, the system 4 being intended to receive signals from the first antenna 10 and signals from the second antenna 20.
The data processing device 5, 6 may be integrated in a unit on board the aircraft a and/or on the ground and may comprise one or more communication interfaces 4 and one or more computers 5, 6. For example, the unit on the ground and the aircraft a may communicate by radio, and both the unit on the ground and the aircraft a include a communication interface 4 of the antenna type. In the form of an embodiment, the data processing device 5, 6 comprises an onboard computer 5 connected to the means for determining the assumed position of the aircraft a and a ground computer 6.
Each computer 5, 6 may comprise a processor or microprocessor of the x-86 or RISC type, for example a controller or microcontroller, a DSP, an integrated circuit such as an ASIC or a programmable circuit such as an FPGA, a combination of the above components or any other combination of components capable of implementing the calculation steps of the guidance method. As will be seen later, the surface computer 6 may be configured to: based on the positioning information transmitted by the positioning means 3, e.g. an inertial unit, and the angular alignment error corresponding to the position drift of the aircraft a, an alignment command is sent to the displacement means 2, e.g. a positioner, the angle is scanned in order to provide beam steering of the antennas 10, 20, a search is made for the best signal direction corresponding to the aircraft a direction, and any angular alignment correction is calculated based on the measurement of the power of the signals received by the antennas 10, 20 during the scan.
Meanwhile, the communication interface 4 may be any analog or digital interface that allows a computer to exchange information with other components of the guidance system 1 (e.g., the antennas 10, 20, the displacement device 2, or the positioning device 3). The communication interface may comprise, for example, an RS232 serial interface, a USB, firewire, HDMI interface or an ethernet type network interface.
Thus, determining the power offset between the first antenna 10 and the second antenna 20 enables to correct a significant drift of the current position of the aircraft a determined on the basis of the signals from its inertial unit 3 (or any other means for determining the assumed position of the aircraft a) by determining whether the position of the aircraft a effectively corresponds to the assumed position, or whether the aircraft a is misaligned with respect to the assumed position.
Guidance of the aircraft a can then be performed using the aforementioned guidance system 1 according to the following steps.
During a preliminary step S0 of the guidance method S, the assumed position of the aircraft a is determined.
For example, the assumed position of the aircraft a may be conventionally determined by an inertial unit 3 integrated on board the aircraft a.
However, this is not restrictive, as the inertial unit 3 may be optional. The assumed position of the aircraft a can be determined by any means 3. For example, the assumed position of aircraft A may be determined based on the last known position of aircraft A as measured by a satellite absolute positioning system (e.g., GPS or Galileo system 1).
During a first step S1, the first antenna 10 and/or the second antenna 20 are aligned in the above-identified (designated) assumed position of the aircraft a.
To this end, the first antenna 10 and the second antenna 20 are displaced so that the respective lines of sight X1, X2 (preferably coaxial) of the first antenna 10 and the second antenna 20 intersect the assumed position of the aircraft a.
During the second step S2 and the third step S3, the power of the signals received by the first antenna 10 and the second antenna 20 is measured simultaneously. In particular, the power of the signal may be measured in dBm.
During a fourth step S4, a deviation between the power of the signal received by the first antenna 10 and the power of the signal received by the second antenna 20 is determined by the data processing device 5, 6, in particular the surface computer 6.
If the determined power deviation is reduced relative to the expected power deviation, the computer 5 may send a shift command to the shifting device 2, for example to a positioner carrying the first and second antennas 20, to angularly shift the first and second antennas by a plurality of beam steering angles (step S6), and to align the boresights X1, X2 of the first and second antennas at a position different from the assumed position established during the preliminary step S0.
During step S6, the first antenna 10 and the second antenna 20 are angularly displaced along the azimuth angle and/or the tilt angle.
Optionally, during step S6, with each shift, the beam steering angle through which the first antenna 10 and the second antenna 20 are shifted is greater than or equal to the second beam width O2 and less than or equal to twice the second beam width O2.
Steps S2 to S6 are then repeated until the power deviation reaches a maximum, or at least reaches a predetermined threshold corresponding to an acceptable alignment between the lines of sight X1, X2 of the antennas 10, 20 and the aircraft a. The alignment associated with the maximum power deviation then substantially indicates the direction of the aircraft a.
In one variant, during step S6, the first antenna 10 and the second antenna 20 may perform a scan in accordance with a predetermined pattern, and then determine a maximum power deviation based on the different power deviations determined for each beam steering angle of the angular scan in order to derive therefrom the direction of the aircraft a.
Preferably, the angular scanning is performed in a periodic pattern.
For example, fig. 4 shows an example of measuring the deviation between the power of the signal received by the first antenna 10 and the power of the signal received by the second antenna 20, which are coaxial and aligned on the same radio transmitter during a sinusoidal scan with respect to the pointing angle.
In another example, the scanning may follow a Lissajous (Lissajous) curve so that the end of the scanning angle region is generally good, while ensuring overlapping intersection of the signal main lobes of the first antenna 10 and the second antenna 20.
In order to determine the alignment correction angle and to align the boresights X1, X2 of the antennas 10, 20 with the direction of the aircraft a, in a first embodiment the ground computer 6 (or any other processing device) may establish a quadratic polynomial approximation (parabolic regression) of the measurements, for example according to the least squares method, connecting the scan angle (along the abscissa, corresponding to the angle between the measured direction during the scan and the assumed position of the aircraft a determined during the preliminary step S0) to the power deviation obtained in step S3. Where applicable, the least squares method may be weighted to take into account the confidence associated with each measurement.
The alignment correction angle is then obtained by determining the abscissa of the maximum value of the quadratic polynomial established as described above (step S7).
Where applicable, to ensure the robustness of the algorithm:
the correction may be limited to the maximum amplitude of the scan, and/or
The correction may be filtered over a number of scan periods using a low-pass filter (e.g. a kalman filter), the time constant of which may be set, for example, to one quarter of a scan period, and/or
The scanning may be triggered based on a standard of deviation of the filtered power, and/or
The scan may be terminated when a correction convergence criterion is met.
Once the scan has been performed and the angular alignment error representative of the drift of the position of the aircraft a and/or any initial alignment error caused by incorrect initial parameterization of the orientation of the carrier positioner 2 on the ground has been determined, the antennas 10, 20 are displaced by the carrier positioner 2 (or any other suitable moving means) in order to align the actual position of the aircraft a identified above.
This embodiment enables the alignment correction angle to be determined. However, the presence of a secondary lobe in the signal of the antenna 10, 20 (see e.g. fig. 1) may increase the level of the signal measured at the edges of the main lobe, and correction calculations may be made in the opposite direction by means of regression calculations that produce convex rather than concave solutions. Then, the maximum value becomes the minimum value.
If the solution is convex, computer 6 may apply a linear regression, and then select the maximum value of the linear regression over the scan interval. Furthermore, the scan magnitude may be selected as a function of the filtered value of the power offset, such that the magnitude is higher when the filtered value is lower.
In a second embodiment, which may be used with the first form of embodiment, the maximum value of the power offset is determined by a time domain convolution method (step S7). This form of embodiment enables, where applicable, to take account of hysteresis in the control of the displacement means 2 by introducing hysteresis times along the azimuth and inclination angles, which enables to correlate the power deviation with the beam steering actually applied to the antennas 10, 20.
The time domain convolution method for calculating the position of the signal maximum is based on the following assumptions:
for narrow beam steering angles, the gain of the antenna with the largest gain appears as a paraboloid of revolution.
For low beam steering angles, the gain of the antenna with the lowest gain is considered constant.
The scanning in each axis (vertical and horizontal) is sinusoidal, of the type σx＝axsin(nxω t), where x represents an azimuth axis or an inclination angle axis. The scan is applied to each axis over a period of T2 pi/ω.
The power deviation Δ RSSI can then be modeled as a paraboloid of revolution by the following equation:
wherein: the Δ RSSI is the power deviation measured in steps S2 and S3,
εAzand εElRespectively the angular error of the azimuth angle and the inclination angle,
σAzand σElRespectively the scan angle of the azimuth and the inclination angle,
theta is the half of the half power beamwidth of the notional parabolic antenna, the gain profile of which corresponds to the difference between the gain profiles of the antennas 10, 20.
Then, the time domain convolution method includes calculating the following amplitudes along each scan axis (i.e., along azimuth and inclination angles) over a scan period of T ═ 2 pi/ω:
thus, the angle error εAz(in azimuth) and angular error εElProportional to the convolution of the power deviation Δ RSSI and the corresponding on-axis scan period (along the tilt angle):
and
it should be noted that the results are for
And nAz≠nElAnd for (σ) as defined abovex＝axsin(nxω t)) corresponding to the scan amplitude of the scan2 AzAnd a2 ElIs effective.
Where applicable, step S6 may be implemented only when the power deviation is less than a predetermined threshold.
Example (c):
the simulation was performed using actual data recorded during the flight of the aircraft a. During this flight, the range reaches 140km, the carrier first (phase 1) moving along a linear track at a speed of 36m/s and then along an endless track or a spiral track as the carrier approaches the ground station (phase 2).
The first antenna 10 has a gain of 30dB and a first half-power beamwidth O1 of 0.9 deg., while the second antenna 20 has a gain of 44dB and a second half-power beamwidth O2 of 4.0.
By simulating the beam steering angle, the power received at the antennas 10, 20 (parabolic antenna 44dB and patch antenna 30dB) is artificially reduced. The power signal (RSSI) of each antenna is corrected in the following manner:
wherein: 0i is the half-power beamwidth of antenna i (first antenna 10 or second antenna 20);
θ i is the beam steering angle of the antenna i (the first antenna 10 or the second antenna 20) with respect to the line of sight Xi (X1 or X2).
The drift is simulated by a drift velocity of 2m/s perpendicular to the alignment axis, which is the worst case scenario. The drift angle of the antenna is simulated by:
wherein: dTLS→VAIs the distance between the antenna 10, 20 on the ground and the aircraft. To emphasize the effect of drift effects on magnitude and speed, the actual test distance used as the basis for the simulation was artificially reduced by 25km in the simulation.
tStart ofIs the simulated drift start time (here 2000s),
Vdrift ofIs the drift velocity in m/s (here 2 m/s).
The noise on the gain measurement is set to 3dB and the model describing the gain variation around the maximum is parabolic. The matching defect was 0.8 °.
The angular displacement of the aircraft is measured every 14 seconds.
Fig. 5 shows the shape of the received power without using the goniometric algorithm for the onset of drift at t-2000 s. In this figure, it can be seen that the signal deviation (on the ordinate) between the two antennas 10, 20 gradually decreases as the beam is steered beyond the first beam width O1.
Fig. 6 to 8 are graphs showing simulation results in which the goniometric algorithm is triggered according to the first embodiment, in which:
0 corresponds to the preparation phase after the power offset filter is reset (after the scan sequence is output);
1 corresponds to a filtering phase without correction calculation;
2 corresponds to the scanning and correction phase.
For this simulation, scans were performed at a period of seven seconds in order to accumulate enough measurement points on one scan to perform accurate correction calculations and ensure that the speed capability of the positioner was not exceeded.
When the drift speed reaches about 4 ° per minute, the power deviation between the two antennas 10, 20 cannot be maintained at the highest level, which translates into a drag force that takes the aircraft out of the active area of the main lobe of the second antenna 20.
Claims (14)
1. A system for guiding an aircraft (A), comprising:
-a first antenna (10) having a first half-power beamwidth (O1),
-a second antenna (20) having a second half-power beamwidth (O2),
the system (1) is characterized in that:
-the first beam width (O1) is at least twice the second beam width (O2),
-within the second beam width (O2) of the second antenna (20), the absolute value of the deviation between the power of the signal received from the first antenna (10) and the power of the signal received from the second antenna (20) is at least equal to 10 dB.
2. The guidance system (1) according to claim 1, wherein the first antenna (20) is omnidirectional.
3. The system (1) according to claim 1 or 2, wherein the first antenna (10) and the second antenna (20) are coaxial.
4. The system (1) according to any one of claims 1-3, wherein the first beam width (O1) is between 3 ° and 5 ° and the second beam width (O2) is between 0.5 ° and 1.5 °.
5. The system (1) according to any one of claims 1-4, wherein the first antenna (10) has a gain between 25dB and 35dB and the second antenna (20) has a gain between 35dB and 50 dB.
6. System (1) according to any of claims 1-5, wherein the first antenna (10) and the second antenna (20) are moved as a single component, and the system (1) further comprises a displacement device (2) for displacing the first antenna (10) and the second antenna (20).
7. Method (S) for autonomous guidance of an aircraft (A) using a guidance system (1) according to any one of claims 1 to 6, comprising the steps of:
s1: positioning a first antenna (10) and/or a second antenna (20) such that a line of sight (X1, X2) of the first antenna (10) and/or the second antenna (20) is aligned on an assumed position of the aircraft (A),
s2: measuring the power of the signal received by the first antenna (10),
s3: simultaneously, measuring the power of the signal received by the second antenna (20),
s4: determining a deviation between the power of the signal received by the first antenna (10) and the power of the signal received by the second antenna (20),
s5: deriving any misalignment error between the line of sight (X1, X2) of the first antenna (10) and/or the second antenna (on the one hand) and the aircraft (on the other hand) based on the determined deviation.
8. The method (S) of claim 7, wherein, during steps S1 to S3, the first antenna (10) and the second antenna (20) are coaxial.
9. The method (S) according to claim 7 or 8, further comprising, before step S5, the steps of:
s6: angularly shifting the first antenna (10) and the second antenna (20) by a plurality of beam steering angles, then repeating steps S2 to S4 for each beam steering angle to determine a respective offset for each beam steering angle, an
S7: the maximum value of the deviation obtained is evaluated.
10. The method (S) according to claim 9, wherein during said shifting step S6, said first antenna (10) and said second antenna (20) perform an angular sweep along an azimuth and/or a tilt angle according to a periodic pattern.
11. Method (S) according to claim 9 or 10, wherein steps S6 and S7 are only performed if the deviation determined in step S5 on the basis of the assumed position of the aircraft (a) is less than a determined threshold value.
12. The method (S) according to claim 10, further comprising, after step S7, the steps of: positioning the first antenna (10) and the second antenna (20) such that the lines of sight (X1, X2) of the first antenna (10) and the second antenna (20) are substantially aligned with the direction corresponding to the maximum of the determined deviation.
13. The method (S) according to any one of claims 9-12, wherein, during step S6, the beam steering angle is greater than or equal to the second beam width (O2) and less than or equal to twice the second beam width (O2).
14. The method (S) according to any one of claims 9 to 13, wherein, during step S7, the maximum value of the deviation is estimated by a time-domain convolution method, or based on a second-order polynomial approximation of the measurements obtained in steps S2 and S3 and associating a given deviation with each beam steering angle.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR1801007 | 2018-09-27 | ||
| FR1801007A FR3086784B1 (en) | 2018-09-27 | 2018-09-27 | GUIDANCE OF AN AIRCRAFT USING TWO ANTENNAS WITH A DIFFERENT OPENING ANGLE |
| PCT/EP2019/076320 WO2020065074A1 (en) | 2018-09-27 | 2019-09-27 | Aircraft guidance using two antennas having different opening angles |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113272671A true CN113272671A (en) | 2021-08-17 |
| CN113272671B CN113272671B (en) | 2023-12-22 |
Family
ID=67107471
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201980074200.2A Active CN113272671B (en) | 2018-09-27 | 2019-09-27 | Aircraft guidance using two antennas with different opening angles |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP3857249A1 (en) |
| CN (1) | CN113272671B (en) |
| FR (1) | FR3086784B1 (en) |
| IL (1) | IL281831B1 (en) |
| WO (1) | WO2020065074A1 (en) |
Citations (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4136343A (en) * | 1977-05-02 | 1979-01-23 | Martin Marietta Corporation | Multiple source tracking system |
| CN1306710A (en) * | 1997-12-16 | 2001-08-01 | 北点技术有限公司 | Appts and method for reusing satellite broadcast spectrum for terrestrially broadcast signals |
| JP2010181074A (en) * | 2009-02-04 | 2010-08-19 | Toshiba Corp | Guidance device |
| CN103454647A (en) * | 2012-06-01 | 2013-12-18 | 霍尼韦尔国际公司 | Systems and methods for the selection of antennas in aircraft navigation systems |
| CN104319483A (en) * | 2014-10-16 | 2015-01-28 | 中国科学院深圳先进技术研究院 | Controllable antenna system and controlling method for antenna |
| CN105144472A (en) * | 2013-04-02 | 2015-12-09 | 瑞典爱立信有限公司 | Radio antenna positioning |
| CN105186102A (en) * | 2015-09-15 | 2015-12-23 | 西安星通通信科技有限公司 | Digital-beam-tracking-based communication-in-moving antenna system and tracking method |
| US9304198B1 (en) * | 2013-10-04 | 2016-04-05 | Sandia Corporation | Navigator alignment using radar scan |
| US20160178729A1 (en) * | 2014-01-10 | 2016-06-23 | Raytheon Company | Detection of stealth vehicles using vhf radar |
| CN106415672A (en) * | 2014-03-31 | 2017-02-15 | 赛峰电子与防务公司 | Method of transmitting flight data recorded by a black box of an aircraft by a radioelectric beam whose directivity changes if a critical state of the aircraft is detected |
| CN107407937A (en) * | 2015-03-16 | 2017-11-28 | 赛峰电子与防务公司 | The automatic householder method of aircraft lands |
| US20170358851A1 (en) * | 2015-06-05 | 2017-12-14 | Viasat, Inc. | Methods and systems for mitigating interference with a nearby satellite |
| US20180006371A1 (en) * | 2016-07-01 | 2018-01-04 | Gogo Llc | Dynamic effective radiated power (erp) adjustment |
| CN108293094A (en) * | 2016-02-29 | 2018-07-17 | 惠普发展公司有限责任合伙企业 | Determine subject image whether in view finder of camera using unidirectional and omnidirectional antenna |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6417803B1 (en) * | 2001-04-03 | 2002-07-09 | The Boeing Company | Beam alignment system and method for an antenna |
| US7313403B2 (en) * | 2003-08-06 | 2007-12-25 | Hong Kong Applied Science And Technology Research Institute Co., Ltd. | Location positioning in wireless networks |
| WO2008112765A1 (en) * | 2007-03-15 | 2008-09-18 | Compass Auto Tracker Llc | An apparatus and method for a directional finder |
-
2018
- 2018-09-27 FR FR1801007A patent/FR3086784B1/en active Active
-
2019
- 2019-09-27 WO PCT/EP2019/076320 patent/WO2020065074A1/en unknown
- 2019-09-27 EP EP19787163.5A patent/EP3857249A1/en active Pending
- 2019-09-27 IL IL281831A patent/IL281831B1/en unknown
- 2019-09-27 CN CN201980074200.2A patent/CN113272671B/en active Active
Patent Citations (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4136343A (en) * | 1977-05-02 | 1979-01-23 | Martin Marietta Corporation | Multiple source tracking system |
| CN1306710A (en) * | 1997-12-16 | 2001-08-01 | 北点技术有限公司 | Appts and method for reusing satellite broadcast spectrum for terrestrially broadcast signals |
| JP2010181074A (en) * | 2009-02-04 | 2010-08-19 | Toshiba Corp | Guidance device |
| CN103454647A (en) * | 2012-06-01 | 2013-12-18 | 霍尼韦尔国际公司 | Systems and methods for the selection of antennas in aircraft navigation systems |
| CN105144472A (en) * | 2013-04-02 | 2015-12-09 | 瑞典爱立信有限公司 | Radio antenna positioning |
| US9304198B1 (en) * | 2013-10-04 | 2016-04-05 | Sandia Corporation | Navigator alignment using radar scan |
| US20160178729A1 (en) * | 2014-01-10 | 2016-06-23 | Raytheon Company | Detection of stealth vehicles using vhf radar |
| CN106415672A (en) * | 2014-03-31 | 2017-02-15 | 赛峰电子与防务公司 | Method of transmitting flight data recorded by a black box of an aircraft by a radioelectric beam whose directivity changes if a critical state of the aircraft is detected |
| CN104319483A (en) * | 2014-10-16 | 2015-01-28 | 中国科学院深圳先进技术研究院 | Controllable antenna system and controlling method for antenna |
| CN107407937A (en) * | 2015-03-16 | 2017-11-28 | 赛峰电子与防务公司 | The automatic householder method of aircraft lands |
| US20170358851A1 (en) * | 2015-06-05 | 2017-12-14 | Viasat, Inc. | Methods and systems for mitigating interference with a nearby satellite |
| CN105186102A (en) * | 2015-09-15 | 2015-12-23 | 西安星通通信科技有限公司 | Digital-beam-tracking-based communication-in-moving antenna system and tracking method |
| CN108293094A (en) * | 2016-02-29 | 2018-07-17 | 惠普发展公司有限责任合伙企业 | Determine subject image whether in view finder of camera using unidirectional and omnidirectional antenna |
| US20180006371A1 (en) * | 2016-07-01 | 2018-01-04 | Gogo Llc | Dynamic effective radiated power (erp) adjustment |
Non-Patent Citations (5)
| Title |
|---|
| XIE HONGSEN ET AL.: "Analysis of Phased Array Antennas Vibration Effects on the Performance of Shipborne MLS", APPLIED MECHANICS AND MATERIALS * |
| 何清举;孙前贵;: "利用GNSS实现高轨卫星自主导航的新方案", 飞行器测控学报, no. 01 * |
| 孟京: "弹载主INS与SAR天线IMU传递对准方法", 哈尔滨工业大学学报, vol. 44, no. 1 * |
| 王立国;叶亮;: "基于北斗双模终端的散射天线对准系统", 无线电工程, no. 05 * |
| 郭鹏鹏 等: "对再入飞行器精确制导的探讨", 企业技术开发, vol. 34, no. 32 * |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2020065074A1 (en) | 2020-04-02 |
| FR3086784A1 (en) | 2020-04-03 |
| CN113272671B (en) | 2023-12-22 |
| EP3857249A1 (en) | 2021-08-04 |
| IL281831B1 (en) | 2024-06-01 |
| FR3086784B1 (en) | 2020-09-25 |
| IL281831A (en) | 2021-05-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP3239730B1 (en) | Method for improving platform guidance or navigation using uniquely coded signals | |
| US9404754B2 (en) | Autonomous range-only terrain aided navigation | |
| US8886373B2 (en) | System and method for assisting in the decking of an aircraft | |
| JP3656575B2 (en) | Satellite tracking antenna controller | |
| US8521427B1 (en) | Vehicle navigation using cellular networks | |
| US7218273B1 (en) | Method and device for boresighting an antenna on a moving platform using a moving target | |
| US7667645B2 (en) | GPS gyro calibration | |
| US10012736B2 (en) | System and process of determining vehicle attitude | |
| EP2835708A2 (en) | Method and system for remotely controlling a vehicle | |
| JP2019105465A (en) | Deception signal detection system and deception signal detection method | |
| JP5605539B2 (en) | MOBILE POSITION ESTIMATION TRACKING DEVICE, MOBILE POSITION ESTIMATION TRACKING METHOD, AND MOBILE POSITION ESTIMATION TRACKING PROGRAM | |
| CN113794497B (en) | Mobile satellite communication antenna terminal with anti-interference positioning function | |
| US20100282894A1 (en) | Antenna pointing bias estimation using radar imaging | |
| CN111638514B (en) | Unmanned aerial vehicle height measurement method and unmanned aerial vehicle navigation filter | |
| CN110741272B (en) | Radio beacon system | |
| CN113701751A (en) | Navigation device based on multi-beam antenna | |
| CN115855041A (en) | Agricultural robot positioning method, system and device | |
| Łabowski et al. | Estimation of flight path deviations for SAR radar installed on UAV | |
| Labowski et al. | Motion compensation for unmanned aerial vehicle's synthetic aperture radar | |
| KR101387665B1 (en) | Self-alignment driving system | |
| CN113272671B (en) | Aircraft guidance using two antennas with different opening angles | |
| CN113721188B (en) | Multi-unmanned aerial vehicle self-positioning and target positioning method under refusing environment | |
| US20230009797A1 (en) | Method and device for measuring the altitude of an aircraft in flight relative to at least one point on the ground | |
| CN113820733A (en) | Moving carrier navigation method and device based on directional antenna and Doppler information | |
| RU2809930C1 (en) | Integrated complex of on-board equipment for unmanned aerial vehicle |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |