EP1005105A2 - Arrangement for generating and automatic tracking of antenna diagrams in elevation for aircrafts during flight manoeuvres with the purpose of data transmission - Google Patents

Abstract

The arrangement has an antenna array of several antennas (39,49) with associated feeder (11-15) networks with transmitter and receiver branches (21,22). The antenna diagram is tracked using a control signal derived from the attitude angle of the aircraft in elevation so that the radiation or reception direction is always horizontal. Transmitted and received signals are phase shifted to produce the antenna diagram using delay lines (33a,33e,..) and mixers (31).

Description

The invention relates to a device for generating and automatically tracking Antenna diagrams in the elevation direction for aircraft, such as airplanes or earthbound missiles, in flight maneuvers for the purpose of data transmission, in particular broadband data transmission.

The broadband data transmission between aircraft moving relative to each other must be in the higher frequency range, that is to say in the microwave range, because only there is a sufficient number Transmission channels with a larger bandwidth are available. But there Free space attenuation increases with increasing frequency and the transmission power does not can be increased arbitrarily, antennas with higher profit, ie directed antennas be used.

So-called phased array antennas are used in the for fast tracking of directional antennas Known in the field of radar technology. The disadvantage of these common phased array antennas is that use them to align the antenna diagrams phase shifters in the transmission frequency range use that, especially at higher frequencies, a considerable attenuation in the phase networks cause and due to the requirements for phase stability in proportion are expensive.

No. 5,493,306 describes a phase-controlled antenna for automatic scanning by tracking an antenna pattern over a given angular range described. Here, phase-shifting delay lines in the Intermediate frequency level arranged and the intermediate frequency is in the individual branches mixed with the signal of a local oscillator in a mixer before the high frequency Signal is fed to the individual antennas of the array. The phase shift to The antenna diagram is tracked according to the principle of the Butler matrix, in its Network the delay lines are integrated.

Furthermore, from the document DE 197 37 136 A1 an antenna with azimuthally controllable Directional effect for the communication between a fixed and several mobile stations become known in which the phase is set in the intermediate frequency range, a frequency conversion by means of a frequency conversion before and after the circuit part one oscillator and one mixer.

The so-called frequency scanning method is known for use with radar devices, that dispenses with adjustable phase shifters and is therefore cheaper. With this frequency scanning method the individual antennas of an array with different lengths Feed lines, so that different depending on the fed frequency Set phase positions on the individual antennas, which results in different radiation angles surrender. Unfortunately, this method is unusable for data transmission because the Transmitted frequency changes depending on the required direction of radiation, so that the reception with a remote station is difficult to implement and antenna tracking after it Principle is completely impossible.

Due to the relative movement between the aircraft there is also a tracking in the azimuth range required, the required tracking rate is relatively low (a few seconds) is. In contrast, the tracking rate required to align the antennas in Elevation range due to the possible flight maneuvers mainly due to the usual rapidly changing flight positions in the roll axis of the aircraft can be much higher. The definition of the respective elevation angle depends on the position angle, i.e. the roll and the Plane pitch angle and azimuth angle to the opposite side.

The invention has for its object to provide a device with which a user data transmission between aircraft during flight maneuvers and quick tracking of Antenna diagrams in the elevation direction with little functional and equipment expenditure is possible.

An advantage of the invention is that the data transmission regardless of the angle at which the aircraft communicating with each other are at a constant carrier frequency can be done. Another advantage is that the phase shift leading to Alignment of the antenna diagrams of the sub-antennas involved is required on low frequencies is generated, so that with the use of relatively inexpensive Components for the transmitting and receiving devices without great effort the stability of the Tracking can be achieved.

The remaining critical part of the circuit in the high frequency range is largely unproblematic with regard to the transmission quality, since the antenna assembly is compatible with the functions for generating and tracking the antenna diagrams in the immediate vicinity of the antenna feed point and extends in the smallest space. So they are Supply lines extremely short, therefore insensitive to phase changes and practical damping-free.

Another advantage is the fact that there is no expensive power amplifier for the transmitting part high performance is required, but a number of small inexpensive parallel connected Low power transmit amplifiers can be used. Through this parallel connection of The reliability is also increased by several transmitter output stages or antenna assemblies the device according to the invention.

The object is achieved with the features of the main claim. alternative Embodiments are specified in the subclaims.

Fig. 1

ein Blockschaltbild, das schematisch den funktionalen Aufbau der erfindungsgemäßen Anordnung zur Erzeugung und Nachführung eines Antennen-Diagramms darstellt,

Fig. 2

ein Beispiel für die Gestalt eines von der Anordnung erzeugten Antennen-Diagramms in verschiedenen Diagramm-Schwenkpositionen und

Fig. 3

die Anordnung eines möglichen Antennenarrays in einer gemeinsamen Einheit.

The invention is described below with reference to the attached FIGS. 1, 2 and 3, which show:

Fig. 1

2 shows a block diagram which schematically represents the functional structure of the arrangement according to the invention for generating and tracking an antenna diagram,

Fig. 2

an example of the shape of an antenna diagram generated by the arrangement in different diagram pivot positions and

Fig. 3

the arrangement of a possible antenna array in a common unit.

The block diagram shown in FIG. 1 shows the arrangement 1 according to the invention for generation and tracking of antenna diagrams with a system controller 3, a modulator 5, a demodulator 6 and an oscillator unit 7, comprising a first 8 and a second 9 oscillator, which are expediently formed together in one module. These dine Networks or assemblies 11, 12, 13, 14, 15, the one transmission branch 21 and one Include receiving branch 22.

Each transmission branch 21 is connected to the modulator 5 and each reception branch via a line 23 22 with a line 24 to the demodulator 6 in connection. Both the first oscillator 8 and also the second oscillator 9 are connected to the system controller 3, via which the arrangement of Figure 1 with other aircraft systems, in particular the position reference system 25 des Airplane is connected. The modulator 5 is used to transmit high-frequency signals with user data act upon. Accordingly, the demodulator 6 sets received modulated high-frequency signals into digital signals (user data), which are then processed can.

Each transmission branch 21 has on the side of the modulator 5 a first mixer 31, which of the first oscillator 8 received high-frequency signals with the modulator 5 coming signals mixes. As a result, the signal coming from the modulator 5, the one Intermediate frequency represents, in a signal at around the alignment frequency different frequency implemented. Seen from the modulator 5 is the first Mixer 31 has a delay line 33a connected to it, which sends the signal through the transmit alignment frequency with a phase shift and that to a second Mixer 35 is guided. The second mixer 35 mixes that from the delay line 33a coming signal with the signal generated by the second oscillator 9. This will make the the delay line 33a incoming signal into a signal with the transmission transmission frequency implemented. This signal becomes a transmit power amplifier or a transmit power amplifier 37 out, which is connected to a transmitting antenna 39. Preferably, the Transmit branches 21 in terms of hardware on an antenna assembly, e.g. on a circuit board integrated.

Similarly, receive branch 22 includes a receive antenna 49 and further from seen from this a receiving amplifier 47, a first mixer 45, one Delay line 43a, 43b, 43c, 43d, 43e and a second mixer 41. Here is the first mixer 45 with the second oscillator 9 and the second mixer 41 with the first Oscillator 8 connected. In this way, that coming from the receiving antenna 49 Signal with the receive transmission frequency with that generated by the second oscillator 9 Mixed signal and changed to a signal with a transmit alignment frequency. This Signal is through the delay line 43a, 43b, 43c, 43d, 43e with a Phase shift applied, supplied to the second mixer 41 and by this a signal coming from the first oscillator 8 mixed so that the signal is a receives constant transmission intermediate frequency. The switch 8b and the switch 9b by the System control are switched, ensure that for the transmission phase, the mixer 31 or 35 of the transmission branch and for the reception phase, the mixers 41 and 45 of the reception branch are supplied with oscillator signals.

The receive transmission frequency is preferably the same as the transmission transmission frequency and is in the range of 10 GHz, for example. The transmit alignment frequency or the receive alignment frequency, however, is lower than that Transmit transmission frequency or the reception transmission frequency, both preferably are in the range of 1 GHz.

In the alignment arrangement 1 there are 11 more parallel to the antenna network described Antenna networks 12, 13, 14, 15 arranged. These are essentially the same Components such as the antenna network 11 described. In a similar way components with the same function in the different working parallel to each other Provide antenna networks with the same reference symbols. The antenna networks 12, 13, 14, 15 thus each have a first mixer 31 and a second one in their transmitting branch 21 Mixer 35, a transmit power amplifier or transmit output stage 37 and a transmit antenna 39 and in their receiving branch 22 a first mixer 45, a second mixer 41, one each Receive amplifier 47 and a receive antenna 49.

The delay lines 33a, 33b, 33c, 33d, 33e and 43a, 43b, 43c, 43d, 43e in the respective Antenna network 11, 12, 13, 14, 15, however, have different lengths. The lengths of the Delay lines are provided so that in the center position or another defined position of the antenna diagram of an antenna or an antenna network 11, 12, 13, 14, 15 the phase positions caused in the delay lines are relative differ from each other by a multiple of the wavelength. So the antenna network points 12 has a delay line 33b in its transmitting branch 21 and 22 in its receiving branch a delay line 43b. Analog are in the antenna network 13 Delay lines 33c and 43c, in the antenna network 14, the delay lines 33d and 43d and the delay lines 33e and 43e are provided in the antenna network 15. The delay lines 33b and 43b are such that one in them Phase shift occurs that is at least one wavelength from that in the Delay lines 33a and 43a occurring phase shifts differs. in the Comparison to the phase shifts occurring in the delay line 33a or 43a occurs in the delay lines 33c and 43c by at least twice the wavelength larger phase shift, one in the delay lines 33d and 43d at least three times the wavelength larger phase shift and in the Delay lines 33e and 43e are larger by at least four times the wavelength Phase shift on. Due to the delay lines of the various antenna networks 11, 12, 13, 14, 15 occurring, different from each other Phase delays are achieved that the respective antenna diagram of the transmit antennas 39 or the receiving antennas 49 at a certain angle to a reference or Zero position is aligned so that the radiation always takes place in the horizontal direction. Because of the relatively large distance of the remote station compared to the height differences of the communicating aircraft is a correction due to different heights of the planes not required. Thereby, a direction becomes under the horizontal direction understood that runs parallel to the surface of the earth. The alignment or change of Antenna diagrams are made by vectorial addition of the individual signals of each transmitting antenna 39 or each receiving antenna 49, so that the signal level in a corresponding manner of the various antenna networks 11, 12, 13, 14, 15 when receiving or transmitting in add up vectorially to a specific send or receive direction. Since the Phase shift in the different antenna networks 11, 12, 13, 14, 15 through the delay lines 33a, 33b, 33c, 33d, 33e or 43a, 43b, 43c, 43d of different lengths, 43e in cooperation with the supply frequencies generated by the first oscillator 8 is can by changing these supply frequencies of the first oscillator 8, which over the first mixer 31 are overlaid with the signal coming from modulator 5, respectively Formation of the main beam direction of the antenna can be effected in a defined direction. This direction is the direction to the aircraft that contains the user data or signals to be sent should receive.

When changing the relative position of the two communicating aircraft Due to flight maneuvers, the resulting target angle becomes the main antenna beam direction by the system control 3 or by a system assigned to it determined and from it the frequency of the first oscillator 8 changed so that an alignment the antenna main beam direction in the desired direction given by the desired angle becomes. The setpoint angle is preferably determined by the aircraft reference system, e.g. the Inertial system, determined and with the azimuth angle to the opposite side in the elevation angle converted.

The second oscillator 9 in the transmitting part 21 causes that from the respective delay line 33a, 33b, 33c, 33d, 33e ultimately coming signal to the constant transmission transmission frequency is implemented. The first from the first oscillator 8 Mixer 31 introduced to align the respective antenna diagrams frequency deviation is thus subtracted from the same frequency deviation by the second oscillator 9 and the respective second mixer 35 are eliminated. In this way they send respective transmit antennas 39 the relevant data with the same transmission frequency, regardless of the orientation of those belonging to the respective transmission antennas 39 Antenna diagrams. This determines the fundamental frequency introduced by the second oscillator 9 essentially the transmit transmission frequency of the transmit antennas 39, since the frequency of the second oscillator 9 is large compared to the frequency of the first oscillator 8 and the frequency of the signal 23 coming from the modulator 5. When mixing the corresponding signals by the mixers 31, 35 in the transmitting part 21, the switches 8b, 9b are set so that the Signals of the first oscillator 8 to the assigned first mixer 31 or the signals of the second oscillator 9 to the respectively connected second mixer 35.

In reception mode there is a superposition of those occurring in the respective reception part 22 Received signals on the one hand via the second oscillator 9 and the one assigned to it first mixer 45 and via the first oscillator 8 in connection with this assigned second mixer 41 instead. For this purpose, the switches 8b, 9b must be set so that the Signals of the first oscillator 8 to the assigned second mixer 41 or the signals of the second oscillator 9 to the respective first mixers 45 connected. The effect that into the respective receiving branches 22 via the first 8 and second oscillators 9 The phase shifts introduced are reversed to that in the respective transmission branches 21 intended mode of action. That coming from the receiving antenna 49 and from Receiving amplifier 47 amplified signal is by means of the second oscillator 9 at a corresponding position of the switch 9b and by means of the respective first mixer 45 a signal superimposed, which is made up of a fundamental frequency and one for the diagram panning required variable frequency forms. This creates a signal with a Reception alignment frequency by the second mixer 41 to an intermediate frequency brought. The signal with the intermediate frequency is sent to the demodulator via line 24 6 fed. By the vectorial addition of those obtained after mixing twice As in the case of transmission, received signals 24 are generated by different phase shifts Chart panning. Seen from the receiving antennas 49, the signals are behind the respective first mixers 45 via the delay lines 43a, 43b, 43c, 43d, 43e led to the phase delay resulting from these delay lines in a Convert diagram change to the reception of signals from the remote station horizontal direction, i.e. from a substantially parallel to the earth's surface trending direction. As for the broadcast case, the two mixes in the first Mixer 45 and in the second mixer 41 the reception frequency to that in line 24 present constant intermediate frequency implemented and supplied to the demodulator 6.

The system controller 3 calculates the elevation angle from the position angles, i.e. the rolling, Nick and azimuth angles, and places them in the required frequency offset for generation which together with the delay lines 33a, 33b, 33c, 33d, 33e or 43a, 43b, 43c, 43d, 43e caused phase shifts in the transmission or reception alignment frequency also effected um by the control signals for the first oscillator 8 and the second oscillator 9 generated. The phase shifts between the antenna networks occur, are provided so that there is a for sending or receiving The antenna main beam direction of the alignment arrangement 1 results in a target angle relative to an aircraft-fixed reference axis, i.e. is aligned with the remote station in every flight position. The phase shift to be provided for this in each antenna network depends on the Distances between the respective transmit 39 or the respective receive 49 antennas the antenna networks 11, 12, 13, 14, 15. These are preferably the same size. Are these different, determine the required phase positions for generation or education and Alignment of the antenna main beam direction according to known algorithms.

By the second mixer 35 in the respective transmission branch 21 and the first mixer 45 in respective receiving branch 22 is achieved that the end frequency or transmission frequency remains constant even if the orientation of the antenna main beam direction changes. In the FIG. 2 shows an example of an antenna main beam direction 70. With the help of described device can this in other pivot positions 71, 72, 73, 74, 75, 76th be moved.

Furthermore, the system controller 3 is provided for switching the control signals from Send on receive and vice versa as well as switch-on and switch-off signals for amplifier modules (not shown). It can also be provided that the system control 3 Send or receive frequency selection by specifying or changing the second Oscillator 9 controls the fundamental frequency.

With the help of the switches 8b and 9b, between the modes of transmission and reception switched. Alternatively, however, if different for sending and receiving Frequencies are used (frequency diversity), parallel transmission and reception be provided. Two first 8 or second 9 oscillators can then be provided.

The modulator 5 and the demodulator 6 can for the data to be sent or received all common types of modulation, such as AM (amplitude modulation), FM (Frequency Modulation), PM (Phase Modulation) or Spread Spectrum.

The entire circuit of the antenna networks 11, 12, 13, 14, 15, possibly also including the antennas 39, 49 is expediently on a common or PCB 80 common to at least one transmitting or receiving branch (FIG. 3) housed, which can be designed as a multilayer. The transmitting antennas can also be used 39 and receiving antennas 49 can be accommodated on this common plate, the antennas e.g. Patch or slot antennas can be and the active components are implemented in SMD or chip technology.

The fact that for each antenna a transmission or reception network and / or Pre-amplifier input stage is present, the reliability of the alignment arrangement 1 high. Above all, this is achieved with little functional equipment.

By mixing the radiation or reception frequency twice with that of the first 8 and second oscillator 9 generated signals is achieved that the phase shift in an easily manageable lower frequency range and thus with lower power. Since the antenna networks 11, 12, 13, 14, 15 are located directly at the entry point of the respective Transmitting 39 or receiving 49 antenna are located, the supply lines are extremely short and therefore for Phase changes insensitive and practically damping-free. Another advantage is there in that no expensive output stages with high power are required for the transmission branches 21, but only a number of small, inexpensive amplifier modules connected in parallel be used. This parallel connection of several antenna networks means that Reliability increased. As a result, the prevailing can be carried out with little effort Requirements can be easily achieved.

In a further embodiment, the transmitting 39 and receiving antennas 49 can be parts of the Aircraft structure. In the case of aircraft, this arrangement results in particular in the Advantage that the radar backscatter cross section and the aerodynamic conditions are not or change only relatively little.

In a further embodiment, each antenna field of the antenna networks 11, 12, 13, 14, 15 for the transmitting (21) and the receiving branch (22) also with only one antenna field be realized. Such an antenna field would then have a corresponding one for each antenna Switches or a circulator can be assigned to these antennas in case of sending the corresponding functions of the transmission branch 21 and in the event of reception to assign corresponding functions of the receiving branch 22.

The antenna networks or assemblies 11, 12, 13, 14, 15 can be in aircraft structural parts be integrated.

Claims (5)

Device for generating and automatically tracking the antenna diagram in the elevation direction during flight maneuvers for the purpose of broadband data transmission between aircraft, in which an array antenna is formed from a plurality of antennas (39, 49) with associated feed networks (11, 12, 13, 14, 15), each with one transmitting branch and one receiving branch (21, 22), and the antenna diagram is formed by means of the control signal (3) calculated in the elevation direction is tracked according to the position angles of the aircraft so that the emission or reception direction always points in the horizontal direction, in which the signals to be transmitted and received by the antennas (39, 49) are subjected to a phase shift in each antenna to generate the antenna diagram, in which the phase shifts between the individual antennas are achieved by means of feed lines assigned to each antenna, which are designed as delay lines (33a, .., 33e, 43a, .., 43e), which differ from one another by at least one or a multiple each one wavelength, so that at frequencies that deviate from the center frequency, different phase positions result for each antenna, in which the delay lines (33a, 33b, 33c, 33d, 33e; 43a, 43b, 43c, 43d, 43e) for generating the phase shifts are located between a first (31, 45) and a second (35, 41) mixer, in which the mixers (31, 45) are each controlled by a first (8) and a second (9) oscillator, the frequency of which is controlled by means of the control signal (3) calculated from the position angles of the aircraft so that the signal frequency in the delay lines (33a, 33b, 33c, 33d, 33e; 43a, 43b, 43c, 43d, 43e) is changed in such a way that a phase shift corresponding to the elevation angle arises from the phase shifts, the generation of the phase shifts being lower compared to the transmission frequency Frequency range occurs and a constant transmission frequency is achieved by the second mixer (35; 41) by subtracting a frequency corresponding to the manipulated variable, and in which the control signal (3) is calculated from the roll, pitch and azimuth angles of the attitude of the aircraft to the remote station. Device for generating and automatically tracking the antenna diagram in the elevation direction for aircraft according to claim 1, characterized in that the antennas (39, 49) of the transmitting branch (21) and the receiving branch (22) by one each common antenna is replaced, which with the other feed networks (11, 12, 13, 14, 15) is connected by a switch or a circulator. Device for generating and automatically tracking the antenna diagram in the elevation direction for aircraft according to claim 1 or 2, characterized characterized in that the feed networks (11, 12, 13, 14, 15) two units through the Integration of the transmission branches (21) and the reception branches (22) to a total of two Form circuit boards. Device for generating and automatically tracking the antenna diagram in the elevation direction for aircraft according to claim 1 or 2 thereby characterized in that the feed networks (11, 12, 13, 14, 15) by a single unit form the integration on a circuit board. Device for generating and automatically tracking the antenna diagram in the elevation direction for aircraft according to one of the preceding claims, characterized in that the antenna networks (11, 12, 13, 14, 15) in aircraft structural parts are integrated.

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