CN111630791A

CN111630791A - Device for receiving linearly polarized satellite signals

Info

Publication number: CN111630791A
Application number: CN201880069438.1A
Authority: CN
Inventors: 约亨·贝克; 安德烈亚斯·劳尔; 奥利弗·利奇克; 卢茨·文德利希; 西蒙·奥托
Original assignee: Nbb Holding Co
Current assignee: Nbb Holding Co; NBB Holding AG
Priority date: 2017-12-01
Filing date: 2018-11-15
Publication date: 2020-09-04
Also published as: EP3718224A1; WO2019105755A1; DE102017128631A1; AU2018376858A1; DE102017128631B4

Abstract

The invention relates to a device (10; 100) for receiving linearly polarized satellite signals, comprising at least one first and one second coupling-out probe (14, 16) which are oriented at an angle to one another and project into a hollow conductor (12) and each provide a linearly polarized input signal, and a signal processing device (13) for processing the two input signals. In order to improve the device (10; 100) such that it can be used to carry out an electronic correction of the polarization error angle that is not susceptible to interference, it is proposed according to the invention that the signal processing device (13) has a first combination element (22) which generates elliptically polarized high-frequency signals that are opposite to one another from the linearly polarized input signals, and that the signal processing device (13) has a controllable signal conversion system (32, 38) which converts the elliptically polarized high-frequency signals into elliptically polarized intermediate-frequency signals, wherein the intermediate-frequency signals have a predefinable phase shift relative to one another, and that the signal processing device (13) has a second combination element by means of which the elliptically polarized intermediate-frequency signals can be combined into the linearly polarized output signals.

Description

Device for receiving linearly polarized satellite signals

Technical Field

The invention relates to a device for receiving linearly polarized satellite signals, having a first and a second outcoupling probe, which are oriented at an angle to one another and project into a hollow conductor, wherein the first outcoupling probe supplies a linearly polarized first input signal, and wherein the second outcoupling probe supplies a linearly polarized second input signal, and having signal processing means for processing the two input signals.

Background

Such a device is intended to receive linearly polarized signals transmitted by satellites that are stationary with respect to the earth, in particular in the frequency range from 10.7GHz to 12.75 GHz. The satellite signals are linearly polarized, wherein two different signals in two polarization planes oriented perpendicular to one another are transmitted by a satellite stationary relative to earth, usually in the same frequency range, in particular at the same carrier frequency. One of the planes of polarization is commonly referred to as the vertical plane of polarization and the other plane of polarization is commonly referred to as the horizontal plane of polarization. The satellite signals are received by means of two coupling-out probes which project into the hollow conductor and are oriented at an angle to one another, preferably perpendicular to one another.

A difficulty in receiving linearly polarized satellite signals is that the outcoupling probe provided for this purpose should ideally be oriented in the polarization plane of the desired satellite signal. Furthermore, the outcoupling probe can absorb only a small part of the energy used by the receiving site, and the outcoupling probe receives not only the desired fraction of the satellite signal but also the fraction of the miniature signal transmitted in the other polarization plane. This results in a deterioration of the signal-to-noise ratio of the signal provided by the coupled-out probe.

The angular deviation between the plane of polarization of the desired satellite signal and the plane in which the coupled-out probe arranged for receiving the satellite signal is oriented is generally referred to as the polarization error angle.

In order to keep the polarization error angle as small as possible and ideally to obtain a polarization error angle of 0 °, receiving apparatuses are known in which the coupling-out probe together with the hollow conductor (into which the coupling-out probe projects) can be mechanically rotated about the longitudinal axis of the hollow conductor. This enables mechanical calibration of the receiving device. If the receiving device is operating stationary and only signals of a single satellite, which is stationary relative to the earth, should be received, this calibration can be performed once when the receiving device is installed. Under normal circumstances, no further calibration is then necessary.

Difficulties arise if the signals of different satellites that are stationary relative to the earth should be received alternately by the receiving device. For this purpose, the receiving device must be aligned with the respective satellite, wherein a correction of the polarization error angle must also be carried out, since the satellite that is stationary relative to the earth occupies different orbital positions, which lead to different polarization error angles.

Additional difficulties arise in the case of receiving devices which are not installed in a fixed position, but which are operated alternately at different locations. It has been shown that different polarization error angles occur at different locations even with respect to the same satellite, which is relatively stationary with respect to the earth, and these polarization error angles have to be corrected separately. If the receiving device is mechanically adjusted each time a location or satellite is changed, this will lead to significant failures based on the mechanical loading of the receiving device.

Particular difficulties arise in the case of receiving devices which are mounted on land or marine vehicles and which are in motion during operation. A continuous correction of the polarization error angle is necessary when the receiving device is in continuous motion, which cannot be realized in practice by mechanical adjustment.

Instead of mechanically rotating the receiving device, for example by means of an electric motor, it is proposed in US5,568,158 to electronically correct the polarization error angle. The input signals provided by the two coupling-out probes oriented perpendicular to one another are processed by means of a signal processing device. The input signals are amplified and attenuated by means of controllable attenuation elements and then combined, wherein additionally the phase of one of the input signals can be shifted by 180 ° by means of a phase shifter. The frequency of the combined signal resulting from the combination of the processed input signals is then reduced by means of a buck converter, so that an output signal with an intermediate frequency is present, which can then be fed to a receiver via a coaxial cable.

The problems caused by mechanically adjusting the receiving device are eliminated by electronic correction of the polarization error angle. It has been found, however, that the electronic correction by means of a controllable damping element, known from US5,568,158, is often disturbing in practice and is difficult to control.

Disclosure of Invention

The object of the invention is therefore to improve a device of the type mentioned at the outset such that it enables a simple and interference-free electronic correction of the polarization error angle.

This object is achieved according to the invention in a device of the generic type in that the signal processing device has a first combination element which generates, from two linearly polarized input signals, left-handed and right-handed elliptically polarized high-frequency signals, and the signal processing device has a controllable signal conversion system for each elliptically polarized high-frequency signal, wherein the high-frequency signals can be converted by means of the signal conversion system into elliptically polarized intermediate-frequency signals which are opposite to one another, wherein the intermediate-frequency signals have a predeterminable phase difference with respect to one another, and the signal processing device has a second combination element, wherein the two elliptically polarized intermediate-frequency signals can be combined into a linearly polarized output signal by means of the second combination element.

An elliptically polarized high-frequency or intermediate-frequency signal is understood to mean a signal which corresponds to an electromagnetic wave and whose deflection from the rest position revolves in an ellipse in a plane oriented perpendicularly to the propagation direction of the wave. The semi-axes of the ellipses can be identical or different, so that elliptical polarization also includes circular polarization as a special case in the present case, in which the deflection of the electromagnetic wave revolves in a circle in a plane oriented perpendicular to the propagation direction. Thus, the term "elliptical polarization" also includes circular polarization at the present time.

The concept of the present invention is that a linearly polarized satellite signal can be obtained completely from a received signal, which is provided by two coupling-out probes oriented at an angle to one another, by combining the linearly polarized input signals of the coupling-out probes into a left-handed elliptically polarized, in particular circularly polarized, high-frequency signal and into a right-handed elliptically polarized, in particular circularly polarized, high-frequency signal, and converting these oppositely elliptically polarized, in particular circularly polarized, signals into intermediate-frequency signals with a predefinable phase difference, and then combining the converted elliptically polarized, in particular circularly polarized, intermediate-frequency signals again into a linearly polarized output signal. The required phase difference of the elliptically, in particular circularly, polarized intermediate frequency signals can be determined by optimizing the signal-to-noise ratio of the output signal.

The device according to the invention enables an electronic correction of the polarization error angle that is less prone to interference. In a first step, the two linearly polarized input signals exiting the probe are converted into two elliptically polarized, in particular circularly polarized, high-frequency signals which are opposite to one another. For this purpose, the signal processing device has a first combination element. In order to generate an elliptically polarized, in particular circularly polarized, first high-frequency signal, for example a left-handed elliptically polarized, in particular circularly polarized, high-frequency signal, the first combination element performs a phase shift of 90 ° of the first input signal and subsequently forms a weighted sum of the 90 ° phase-shifted first input signal and the second input signal unchanged in its phase. In order to generate an elliptically polarized, in particular circularly polarized, second high-frequency signal, i.e. an elliptically polarized, in particular circularly polarized, high-frequency signal, for example with a right-hand rotation, the first combination element performs a phase shift of the second input signal by 90 ° and subsequently forms a weighted sum of the 90 ° phase-shifted second input signal and the first input signal unchanged in its phase. The first and second input signals, which are phase-shifted by 90 ° and unchanged in their phase, can be weighted in the sum formation, so that signals with the same weight or also with different weights are combined. Equal weighting of the signals leads to the special case of circular polarization of the sum signal, while different weighting leads to non-circular elliptical polarization of the sum signal.

Subsequently, the elliptically, in particular circularly, polarized high-frequency signals which are opposite to one another are converted by means of a controllable signal conversion system into elliptically, in particular circularly, oppositely polarized intermediate-frequency signals which have a phase difference which can be set in advance. For this purpose, the at least one signal conversion system can also perform a predefinable phase shift in addition to the frequency conversion, so that the intermediate frequency signals have a predefinable phase difference with respect to one another.

Preferably, the two signal conversion systems perform a phase shift in addition to the frequency conversion. For example, a first controllable signal conversion system can be supplied with a left-handed elliptically polarized, in particular circularly polarized, high-frequency signal, which is converted by the first signal conversion system into a left-handed elliptically polarized, in particular circularly polarized, intermediate-frequency signal with a changed phase, and a second controllable signal conversion system can be supplied with a right-handed elliptically polarized, in particular circularly polarized, high-frequency signal, which is converted by the second signal conversion system into a right-handed elliptically polarized, in particular circularly polarized, intermediate-frequency signal with a changed phase.

In a further step, elliptically, in particular circularly, polarized intermediate frequency signals which are opposite to one another are combined into a linearly polarized output signal by means of a second combination element.

It has now been demonstrated that the signal-to-noise ratio of a linearly polarized output signal can be optimized by varying the phase shift performed by at least one controllable signal conversion system, wherein the output signal corresponds to a satellite signal transmitted in a first polarization plane, for example to a satellite signal transmitted in a horizontal polarization plane. The output signal has practically no share of the satellite signal transmitted in a second plane of polarization, e.g. a vertical plane of polarization, orthogonal to the first plane of polarization. The addition of the oppositely elliptically, in particular circularly, polarized intermediate signals eliminates the proportion of the interfering second satellite signal, wherein the elimination can be recognized by the fact that the output signal has the best signal-to-noise ratio.

In an electrically rotatable receiving device, the polarization error angle can be corrected in such a way that the signal-to-noise ratio of the output signal provided by the receiving device is optimized by the mechanical rotation of the device. In the device according to the invention, no mechanical rotation is necessary, rather the signal-to-noise ratio of the output signal can be optimized by changing the phase difference of the oppositely elliptically polarized, in particular circularly polarized, intermediate frequency signal.

As already mentioned, the first combination unit is configured in such a way that a left-handed elliptically polarized high-frequency signal and a right-handed elliptically polarized high-frequency signal can be generated from the two linearly polarized input signals. It is particularly advantageous if, by means of the first combination element, a left-handed circularly polarized high-frequency signal and a right-handed circularly polarized high-frequency signal can be generated from the two linearly polarized input signals. As already mentioned, this can be achieved by performing equal weighting when summing first and second input signals that are phase-shifted by 90 ° and that have not changed in their phase.

For controlling the signal conversion system, the signal processing device advantageously has a control unit.

Preferably, the use of a control unit is allowed to provide the at least one signal conversion system with a special phase control signal.

Advantageously, the two signal conversion systems each perform a phase shift, wherein the first signal conversion system can be supplied with a first phase control signal corresponding to a first phase shift angle, and wherein the second signal conversion system can be supplied with a second phase control signal corresponding to a second phase shift angle.

The phase shift angles are not necessarily the same. In particular, it can be provided that the two phase shift angles differ only in their sign, but do not differ in their absolute value, so that a left-handed circularly polarized signal is shifted in its phase by, for example, a phase angle + Φ, while a right-handed circularly polarized signal is shifted by a phase angle- Φ, where Φ can assume values between 0 ° and 90 °.

Preferably, a microprocessor can be used as the control unit.

The controllable signal conversion system is preferably designed as a buck converter, wherein at least one signal conversion system has a phase-locked loop (phase-locked loop) which can be supplied with a phase control signal. Buck converters with a phase-locked loop (also referred to as phase-locked loop) are known to those skilled in the art. Standard circuits are involved, which are produced inexpensively in large numbers for completely different purposes of use. The phase control signal can be used to shift the phase of the signal converted by the buck converter.

Preferably, the two controllable signal conversion systems have a phase-locked loop (phase-locked loop) which can be supplied with the phase control signal.

Advantageously, the signal conversion systems are each formed with a single integrated circuit. Integrated circuits can constitute a compact set of electrical structures that can be inexpensively manufactured in large quantities.

For example, it can be provided that the phase-locked loop of the at least one signal conversion system is connected to an oscillating circuit, which supplies an oscillating signal to the phase-locked loop, and that the phase-locked loop has a loop filter, which can be loaded with a phase control current. Phase locked loops with loop filters are well known to those skilled in the art and therefore need not be elaborated upon. The phase control current is a phase control signal by means of which a phase shift can be obtained. The phase control current is loaded, that is to say introduced into the loop filter, to cause a phase shift of the oscillator signal and this in turn causes a phase shift of the intermediate frequency signal provided by the buck converter.

Advantageously, a controllable current supply element is associated with the phase-locked loop, which supplies the phase-controlled current to the loop filter of the phase-locked loop.

Preferably, the current providing element is controllable by a control unit of the signal processing device.

It can be provided that the current supply element is designed as a current pulse sensor or as a digital/analog converter, which is acted upon by the control unit for controlling the signal.

In an advantageous embodiment of the invention, the controllable signal conversion systems each have a phase-locked loop (phase-locked loop), wherein the phase-locked loop is connected to a controllable DDS synthesis circuit (Direct digital synthesis-synthesis) which supplies a reference clock signal to the phase-locked loop, wherein the frequencies of the reference clock signals are identical and the phases of the reference clock signals have a phase difference (phase offset) that can be set. Controllable DDS synthesis circuits are known per se to the person skilled in the art and therefore do not need to be elaborated on at present. With the aid of a controllable DDS synthesis circuit, two phase control signals can be generated in the form of two reference clock signals having the same frequency and a predefinable phase offset. One of the two reference clock signals may be supplied to the phase-locked loop of the first buck converter, while the other reference clock signal may be supplied to the phase-locked loop of the second buck converter. This results in the buck converter providing an intermediate frequency signal which differs in its phase in a predefinable manner.

Preferably, the DDS synthesis circuit is controllable by a control unit of the signal processing device.

The buck converters preferably each have a mixing element, with the aid of which the frequency of the elliptically, in particular circularly, polarized high-frequency signal can be converted into an intermediate frequency.

The intermediate frequency is preferably 0.95GHz to 2.15 GHz.

Advantageously, the signal processing device has an amplifier with a controllable degree of amplification for each linearly polarized input signal. This allows amplifying the linearly polarized input signals provided by the coupled-out probe independently of one another in a predefinable manner. The amplifiers may be alternately turned off for testing purposes.

Advantageously, the signal processing device has an amplifier control element for controlling the amplifier.

Preferably, the control signal may be provided by the control unit to the amplifier control element.

In an advantageous embodiment of the invention, the signal processing device has a controllable level controller for each elliptically polarized, in particular circularly polarized, intermediate frequency signal. The level controller can be designed, for example, as a controllable damping element or also as a controllable amplification element. The undesired level differences of the two intermediate frequency signals can be eliminated by means of the level adjuster. In particular, it can be ensured by means of a controllable level regulator that the level of the intermediate frequency signal supplied to the second combination element is equally high, so that the same input level is present at the input of the second combination element. This in turn leads to an optimum amplitude of the output signal, wherein undesired signal contributions are suppressed.

Advantageously, the level regulator can be provided with a control signal by the control unit.

As mentioned, it is advantageous that the level of the elliptically, in particular circularly, polarized intermediate frequency signal can be adjusted to the same value, since an output signal with a high amplitude and a small proportion of undesired signals can thereby be obtained.

In an advantageous embodiment of the invention, a filter element is arranged downstream of the second combination element. Undesired spectral components of the output signal can be removed by means of the filter element.

The filter element is preferably designed as a low-pass or band-pass filter.

In order to be able to supply the individual components of the signal processing device with control signals which are dependent on the power of the output signal, it is advantageous if the signal processing device has a power detector which can be acted upon by the second combination element with the signal to be measured which corresponds to the output signal of the device, and the power detector supplies the control unit of the signal processing device with measured values which correspond to the measured power. The power detector can be used to control the aforementioned level regulator, for example, in such a way that the amplitude of the intermediate frequency signal present at the input of the combination element is equally large.

Drawings

The following description of advantageous embodiments is provided to illustrate the invention in detail with reference to the accompanying drawings. Wherein:

FIG. 1: a block diagram of an advantageous first embodiment of an apparatus for receiving linearly polarized satellite signals is shown;

FIG. 2: a block diagram of an advantageous second embodiment of an arrangement for receiving linearly polarized satellite signals is shown.

Detailed Description

An advantageous first embodiment of the device according to the invention for receiving linearly polarized satellite signals is shown in fig. 1 and generally takes the reference numeral 10. The device has a hollow conductor 12 and signal processing means 13. The first coupling-out probe 14 and the second coupling-out probe 16 project into the hollow conductor 12. The two coupled-out

probes

14, 16 are oriented at an angle to one another, preferably perpendicular to one another.

The first outcoupling probe 14 supplies a linearly polarized first input signal to a controllable first amplifier 18, which is amplified by the controllable first amplifier 18 and supplied to a first input 20 of a first combination element 22. The second coupling-out probe 16 supplies a second linearly polarized input signal to a controllable second amplifier 24, which second input signal is amplified by the controllable second amplifier 24 and supplied to a second input 26 of the first combination element 22.

First combination element 22 generates a left-handed elliptically polarized, in particular circularly polarized high-frequency signal from the two linearly polarized input signals, which is supplied via a first strip 28 to a signal input 30 of a controllable first signal conversion system 32. Furthermore, first combination element 22 generates a right-handed elliptically polarized, in particular circularly polarized high-frequency signal, which is supplied via a second band pass 34 to a signal input 36 of a controllable second signal conversion system 38.

In order to generate a left-handed elliptically polarized, in particular circularly polarized high-frequency signal, the first combination element 22 performs a phase shift of the linearly polarized first input signal present at the first input 20 by 90 ° and subsequently forms a weighted sum of the phase-shifted linearly polarized first input signal and the linearly polarized second input signal present at the second input 26, which is unchanged in its phase. The sum of these two signals forms a left-handed elliptically polarized, in particular circularly polarized, high-frequency signal.

In order to generate a right-handed elliptically polarized, in particular circularly polarized, high-frequency signal, the first combination element 22 performs a phase shift of the linearly polarized second input signal present at the second input 26 and subsequently forms a weighted sum of the phase-shifted linearly polarized second input signal and the linearly polarized first input signal present at the first input 20, which is unchanged in its phase. The sum of these two signals forms a right-handed elliptically polarized, in particular circularly polarized, high-frequency signal.

In the summation formation, the first and second input signals, which are phase-shifted by 90 ° and which have not been changed in their phase, can be weighted such that signals having the same weight or also different weights are summed. Equal weighting of the signals leads to the special case of circular polarization of the high-frequency signals, while different weighting leads to non-circular elliptically polarized high-frequency signals.

The first combination element 22 can be designed, for example, as a directional coupler or as a 3dB hybrid coupler.

The controllable first signal conversion system 32 is configured as an integrated circuit with a first buck converter 33 having a first mixing element 35 and a second phase-locked loop 37(phase-locked loop) with a first loop filter 47. By means of the controllable first signal conversion system 32, the left-handed elliptically polarized, in particular circularly polarized, high-frequency signal is converted into a left-handed elliptically polarized, in particular circularly polarized, intermediate signal, wherein at the same time a predetermined first phase shift is carried out as a function of a first phase control current which is present at a control input 39 of the controllable first signal conversion system 32. The first phase control current constitutes a first phase control signal which is supplied to a first loop filter 47 of the first phase locked loop 37.

The controllable second signal conversion system 32 is configured as an integrated circuit with a second buck converter 40, which has a second hybrid element 41 and a second phase-locked loop 43(phase-locked loop) with a second loop filter 53. By means of the controllable second signal conversion system 32, the right-handed elliptically polarized, in particular circularly polarized, high-frequency signal is converted into a right-handed elliptically polarized, in particular circularly polarized, intermediate signal, wherein at the same time a predetermined second phase shift is carried out as a function of a second phase control current which is present at a control input 45 of the controllable second signal conversion system 38. The second phase control current constitutes a second phase control signal which is supplied to a second loop filter 53 of the second phase locked loop 43.

The intermediate frequency of the elliptically, in particular circularly, polarized intermediate frequency signal is 0.95GHz to 2.15 GHz.

To obtain the first phase shift, the first phase control current provided at the control input 39 of the controllable first signal conversion system 32 is coupled into the first loop filter 47 of the phase locked loop 37 of the controllable first signal conversion system 32. The oscillation circuit 46 supplies the phase-locked loop 37 with an oscillation signal. By coupling in the first phase control current, a phase shift of the oscillator signal occurs, and this in turn results in a first phase shift of the left-handed elliptically polarized, in particular circularly polarized, intermediate frequency signal provided by the controllable first signal conversion system 32.

To obtain the second phase shift, the second phase control current provided at the control input 45 of the second controllable signal conversion system 38 is coupled into the second loop filter 53 of the phase locked loop 43 of the second controllable signal conversion system 32. The oscillation circuit 46 supplies the phase-locked loop 43 with an oscillation signal which is identical to the oscillation signal supplied to the first phase-locked loop 37. By coupling in the second phase control current, a phase shift of the oscillator signal occurs, and this in turn results in a second phase shift of the right-handed elliptically, in particular circularly, if signal provided by the controllable second signal conversion system 32.

The phase shift by the controllable first signal conversion system 32 is inversely equal to the phase shift by the controllable second signal conversion system 38. The controllable first signal conversion system 32 results in a phase shift by an angle + phi, while the controllable second signal conversion system 38 results in a phase shift by an angle-phi.

The control of the

signal conversion systems

32 and 38 takes place by means of a control unit 50 which is designed in the embodiment shown as a microprocessor 32.

The microprocessor 52 loads the first current supply element 54 with a first control signal, which corresponds to a first phase shift angle predefined by the microprocessor, and causes the first current supply element 54 to couple a first phase control current into the first loop filter 47 of the phase locked loop 37 of the controllable first signal conversion system 32, wherein the coupling takes place via the first phase control line 56 and the control input 39 of the controllable first signal conversion system 32.

In a corresponding manner, the microcontroller 52 loads the second current supply element 58 with a second control signal, which corresponds to a second phase shift angle predetermined by the microprocessor, and causes the second current supply element 58 to couple the second phase control current into the first loop filter 53 of the phase-locked loop 43 of the controllable second signal conversion system 38, wherein the coupling takes place via the second phase control line 60 and the control input 45 of the controllable second signal conversion system 38.

As already mentioned, the second phase shift angle is not the same as the first phase shift angle. Preferably, the second phase shift angle is inversely equal to the first phase shift angle.

The left-handed elliptically polarized, in particular circularly polarized, intermediate frequency signal provided by first signal conversion system 32 is supplied via a controllable first level adjuster 62 to a first input 64 of a second combination element 66. The right-handed elliptically polarized, in particular circularly polarized, intermediate frequency signal provided by the controllable second signal conversion system 38 is supplied via a controllable second level regulator 68 to a second input 70 of the second combination element 66. The level of the intermediate frequency signals present at the inputs 64 and 70 is adjusted to the same value by means of the

level adjusters

62 and 68. The second combination element 66 combines the intermediate frequency signals by summing them. Since the intermediate frequency signals are elliptically, in particular circularly, polarized in opposite directions to one another and since the amplitudes of the intermediate frequency signals present at the input terminals 64 and 70 are equally large, the combination of the intermediate frequency signals results in a linearly polarized output signal being present at the first output 72 of the second combination element 66.

The second combination element 66 can be designed, for example, as a directional coupler or as a 3dB hybrid coupler.

The signal-to-noise ratio of the output signal can be maximized by varying the phase shift angle Φ. The output signal optimized by a suitable choice of the phase shift angle Φ corresponds to a linearly polarized satellite signal which is transmitted in the polarization plane and is received in portions by the two

outcoupling probes

14 and 16. The output signal provided by the second combination element 66 has practically no signal contribution of the linearly polarized second satellite signal transmitted in a second polarization plane oriented perpendicular to the first polarization plane.

If an output signal corresponding to the linearly polarized second satellite signal should be provided, the phase angle Φ only needs to be increased by 90 °.

The change of the phase shift angle Φ to optimize the output signal is effected by means of a microprocessor 52, which can be programmed for this purpose. For example, microprocessor 52 can be preset with an initial value for the phase shift angle, which changes in steps or also continuously until the output signal has the greatest signal-to-noise ratio. Alternatively, it can be provided that the microprocessor calculates an initial value of the phase shift angle, wherein in particular the current position of the device 10, i.e. its GPS data, and the desired orbital position of the satellite that is stationary relative to the earth can be integrated into the calculation.

A filter element 74, which in the example shown is designed as a bandpass 76, is coupled to first output 72 of second combination element 66. The filtered output signal may be transmitted from the band pass 76 via a common coaxial cable 80 to a receiver not shown in the figure, for example a TV receiver.

A control signal can be transmitted from a receiver, not shown in the figures, via a coaxial cable 80 to a first control signal input 82 of microprocessor 52, wherein the control signal can be coupled out of coaxial cable 80 by means of a coupling-out element 84. A filter 86 is downstream of the coupling-out element 84, so that the first control signal input 82 can be supplied with a control signal having a frequency of 22kHz, for example. In particular, the control signal transmitted to microprocessor 52 via coaxial cable 80 may be a measure of the signal-to-noise ratio for the output signal.

Second combining element 66 has a second output 88 to which a power detector 90 is coupled. The power detector 90 is electrically connected to a second control signal input 94 of the microprocessor 52. The signal to be measured, which corresponds to the output signal present at the first output 72, can be supplied by the second combination element 66 to the power detector 90. The power detector provides a measured value corresponding to the measured power to the microprocessor 52. Based on this measured value, the microprocessor 52 can control two

level regulators

62 and 68, by means of which the level of the elliptically, in particular circularly, polarized intermediate frequency signal can be changed in such a way that the same level is present at the inputs 64 and 70 of the second communication element 66.

In consideration of the measured values provided by the power detector 90, the microprocessor 52 can also provide a control signal to the amplifier control unit 96, which causes the amplifier control unit 96 to provide corresponding control signals to the

controllable amplifiers

18 and 24, which control signals each correspond to a specific degree of amplification. This makes it possible to change the level of the linearly polarized input signal. Furthermore, functional tests can be performed by alternately switching off the

amplifiers

18, 24, and undesired phase errors can be identified.

An advantageous second embodiment of the device for receiving linearly polarized satellite signals according to the invention is schematically illustrated in fig. 2 and generally takes the reference numeral 100.

The device 100 is largely designed identically to the device 10 described earlier with reference to fig. 1. Accordingly, the same reference numerals are used in fig. 2 as in fig. 1 for the same components, and reference is made to the above explanation about these components to avoid repetition.

Device 100 differs from device 10 in that phase locked

loops

37 and 43 of

buck converters

33 and 40 are connected to a controllable DDS synthesis circuit 102, which provides phase control signals in the form of reference clock signals to both phase locked

loops

37, 43, respectively. The reference clock signals are identical in terms of their frequency, however, they have a phase difference (phase offset) that can be set in their phase. The DDS synthesis circuit 102 is controlled by the control unit 50, which presets the DDS synthesis circuit 102 with a phase difference. The coupling of the phase control current into the phase locked

loop

37, 43 is eliminated in the device 100. In contrast, it is achieved by providing reference clock signals which are identical in terms of their frequency but have a predefinable phase difference in their phase that the step-down

converters

33 and 40 provide oppositely elliptically polarized, in particular circularly polarized, intermediate frequency signals which differ in their phase in accordance with the predefinable phase difference of the reference clock signal.

In the arrangement 100, the oppositely elliptically polarized, in particular circularly polarized, intermediate frequency signals are also combined with one another after they have passed through the

controllable level adjusters

62 and 68, so that a linearly polarized output signal is present at the output 72 of the second combination element 66. By varying the phase shift angle of the two elliptically, in particular circularly, polarized intermediate frequency signals, the signal-to-noise ratio of the output signal can be optimized. The change of the phase shift angle is performed by means of a DDS synthesis circuit 102 controlled by the control unit 50, which supplies the phase-locked

loops

37 and 43 with phase control signals in the form of reference clock signals having a phase difference preset by the control unit 50.

The

devices

10 and 100 make it possible to receive linearly polarized satellite signals in an optimum manner in any polarization plane, without the need for mechanical calibration of the

device

10 and 100 movements for this purpose. The satellite signals are coupled into the hollow conductor 12 and are received in each case by a specific portion by two coupling-out

probes

14, 16, which are oriented at an angle to one another, preferably perpendicular to one another. The signal contribution corresponds to the orientation of the coupled-

out probe

14, 16 with respect to the polarization plane of the satellite signal. The linearly polarized input signals provided by the two coupling-out

probes

14, 16 are converted into oppositely elliptically polarized, in particular circularly polarized, high-frequency signals, which are converted into oppositely elliptically polarized, in particular circularly polarized, intermediate-frequency signals, wherein a phase shift by a predetermined phase shift angle is simultaneously carried out by providing a phase control signal. The elliptically polarized, in particular circularly polarized, intermediate frequency signals are then combined to a linearly polarized output signal. The signal-to-noise ratio of the output signal can be maximized by varying the phase shift angle. As already mentioned, the microprocessor 52 can be pre-set with a first phase shift angle, or the first phase shift angle can be calculated by the microprocessor 52, wherein the location coordinates (GPS coordinates) of the

devices

10 and 100 and the desired orbital position of the satellite stationary relative to the earth can be incorporated into the calculation. The phase shift angle can then be varied by the microprocessor 52 in stages or also continuously until an optimum signal-to-noise ratio of the output signal is reached. The output signal then has the largest amplitude and in fact only the signal contribution of the desired linearly polarized satellite signal, but in practice no signal contribution of the undesired satellite signal. Thus, correction of the polarization error angle can be achieved electronically with the

devices

10 and 100.

Claims

1. Device for receiving linearly polarized satellite signals, having at least one first and one second outcoupling probe (14, 16) which are oriented at an angle to one another and project into a hollow conductor (12), wherein the first outcoupling probe (14) provides a linearly polarized first input signal, and wherein the second outcoupling probe (16) provides a linearly polarized second input signal, and having a signal processing device (13) for processing the two input signals, characterized in that the signal processing device (13) has a first combination element (22) which generates a left-handed and a right-handed elliptically polarized high-frequency signal from the two linearly polarized input signals, and in that the signal processing device (13) has a controllable signal conversion system (32) for each of the two elliptically polarized high-frequency signals, 38) Wherein the high-frequency signals are converted by means of two controllable signal conversion systems (32, 38) into elliptically polarized intermediate-frequency signals which are opposite to one another, wherein the intermediate-frequency signals have a phase difference which can be predetermined relative to one another, and the signal processing device (13) has a second combination element (66), wherein the two elliptically polarized intermediate-frequency signals can be combined into a linearly polarized output signal by means of the second combination element (66).

2. Device according to claim 1, characterized in that a left-handed circularly polarized high-frequency signal and a right-handed circularly polarized high-frequency signal can be generated from two linearly polarized input signals by means of the first combination element (22).

3. The device according to claim 1 or 2, characterized in that the signal processing means (13) have a control unit (50) for controlling the signal conversion system (32, 38).

4. Device according to claim 3, characterized in that the control unit (50) is designed as a microprocessor (52).

5. Device according to one of the preceding claims, characterized in that the controllable signal conversion system (32, 38) is designed as a buck converter (33, 40), wherein at least one signal conversion system (32, 38) has a phase-locked loop (37, 43) which can be supplied with a phase control signal.

6. The device according to claim 5, characterized in that the controllable signal conversion system (32, 38) is designed as an integrated circuit.

7. Device according to claim 5 or 6, characterized in that the phase-locked loop (37, 43) is connected to an oscillation circuit (46) which supplies an oscillation signal to the phase-locked loop (37, 43), and in that the phase-locked loop (37, 43) has a loop filter (47, 53) which can be loaded with a phase control current, wherein the phase control current is a phase control signal.

8. Device according to claim 5, 6 or 7, characterized in that a controllable current supply element (54, 58) is assigned to the phase-locked loop (37, 43), which current supply element supplies a phase control current to a loop filter (47, 53) of the phase-locked loop (37, 43).

9. Device according to claim 8, characterized in that the current supply element (54, 58) is designed as a current pulse sensor or as a digital-to-analog converter.

10. Device according to claim 5 or 6, characterized in that the controllable signal conversion systems (32, 38) each have a phase-locked loop (37, 38), wherein the phase-locked loops (37, 43) are connected to a controllable DDS synthesis circuit (102) which supplies the phase-locked loops (37, 43) with a phase control signal in the form of a reference clock signal, wherein the frequencies of the reference clock signals are identical and the phases of the reference clock signals have a phase difference that can be predetermined from one another.

11. The device according to one of claims 5 to 10, characterized in that the buck converters (33, 40) each have a mixing element (35, 41), wherein the frequency of the elliptically polarized high-frequency signals can be converted into an intermediate frequency by means of the mixing elements (35, 41).

12. Device according to any of the preceding claims, characterized in that the signal processing means (13) have a controllable amplifier (18, 24) for each linearly polarized input signal.

13. The device according to claim 12, characterized in that the controllable amplifier (18, 24) is connected to an amplifier control element (96).

14. The apparatus according to claim 13, characterized in that the amplifier control element (96) is provided with a control signal by a control unit (50).

15. Device according to any of the preceding claims, characterized in that the signal processing means (13) have a controllable level adjuster (62, 68) for each intermediate frequency signal.

16. Device according to claim 15, characterized in that the level regulators (62, 68) can be provided with control signals, respectively, by a control unit (50).

17. Device according to any of the preceding claims, characterized in that the level of the intermediate frequency signal can be adjusted to the same value.

18. Device according to any one of the preceding claims, characterized in that a filter element (74) is provided after the second combination element (66).

19. Device according to claim 18, characterized in that the filter element (74) is designed as a band pass (76).

20. The device according to one of the preceding claims, characterized in that the signal processing device (13) has a power detector (90) which can be loaded by the second combination element (66) with a signal to be measured which corresponds to the output signal of the second combination element (66), wherein the power detector (90) supplies a measured value corresponding to the measured power to the control unit (50).