阅读说明：本技术 用于补偿干扰影响的方法和装置 (Method and apparatus for compensating for interference effects ) 是由 M·福西克 P·古尔登 M·戈廷格 于 2018-04-25 设计创作，主要内容包括：本发明涉及一种用于补偿无线电定位系统中的噪声、尤其是相位噪声的方法,所述无线电定位系统具有非相关的第一和第二发送接收单元,其中,基于由第一发送接收单元发送的和由第一发送接收单元接收的信号来生成第一测量信号(s<Sub>m1</Sub>(t))和至少一个第二测量信号(s<Sub>m2</Sub>(t)),其中,第一测量信号(s<Sub>m1</Sub>(t))的通过噪声、尤其是相位噪声引起的第一频移相反于、尤其是正好相反于第二测量信号(s<Sub>m2</Sub>(t))的通过噪声、尤其是相位噪声引起的第二频移。(The invention relates to method for compensating noise, in particular phase noise, in a radio positioning system having uncorrelated and second transceiver units, wherein a th measurement signal(s) is generated on the basis of signals transmitted by a th transceiver unit and received by a th transceiver unit m1 (t)) and at least second measurement signals(s) m2 (t)), wherein the th measurement signal(s) m1 (t)) the th frequency shift caused by noise, in particular phase noise, is opposite, in particular exactly opposite, to the second measurement signal(s) m2 (t)) by a second frequency shift caused by noise, in particular phase noise.)

1. Method for compensating noise, in particular phase noise, or system deviations in a secondary radar system, in particular a radio positioning system, having an uncorrelated th and at least th second transmitting-receiving units, wherein,

transmitting th transmission signal(s) through th transceiver unit₁₁(t)), the st th transmission signal has a th th interference component caused by noise or system deviation,

signals(s) with st ₁₁(t)) simultaneously or overlapping in time, transmitting at least second transmission signals(s) through the th transceiver unit₁₂(t)), the second th transmission signal has a second th interference component caused by noise or system deviation,

each transmitting signal(s)₁₁(t)，s₁₂(t)) is arranged such that, when the respective transmitted signal is reprocessed and evaluated, the phase and/or frequency shift caused by the interference component is at least partially compensated.

2. The method according to claim 1 or 2, wherein,

th signal(s) is transmitted by the second transmitting and receiving unit₂₁' (t)) and at least second signals(s)₂₂'(t))，

Receiving the transmitted second signal(s) by a th transceiver unit₂₁' (t)) as a received th second signal(s)₂₁(t)) and receiving the transmitted second signal(s)₂₂' (t)) as a received second signal(s)₂₂(t))，

By the transmitted st th signal(s)₁₁(t)) and a received th second signal(s)₂₁(t)), in particular by mixing and/or by correlation, preferably in the form of complex conjugate multiplication, to generate the th measurement signal(s)_m1(t)), and a second signal(s) transmitted-method and apparatus for reducing interference caused by phase noise in a radar system₁₂(t)) and a received second signal(s)₂₂(t)), in particular by mixing and/or by correlation, preferably in the form of a complex conjugate multiplication, to generate the second measurement signal(s)_m2(t))。

3. Method according to claim 2, wherein the th measurement signal(s)_m1(t)) th interference component of the second measurement signal(s) caused by noise or system deviations_m2(t)) the second interference components caused by noise or system offset are complex conjugated to each other.

4. method according to the preceding claim, wherein a signal(s) is transmitted₁₁(t)) has at least th factors, the th factor in combination with a transmitted second signal(s)₁₂(t)) complex conjugate by a second factor.

5. method according to the preceding claim, wherein a signal(s) is transmitted₁₁(t)) includes at least frequency ramps having a th slope, and transmits a second th signal(s)₁₂(t)) comprises fewer frequency ramps having a second slope, wherein the th slope has a different sign than the second slope, wherein the amount of the th and second slopes is preferably at least substantially the same.

6. The method according to of the preceding claim, in particular according to of claims 2 to 5, wherein the signal(s) for the th measurement is generated by the same th HF generator (LO1)_m1(t)) and a second measurement signal(s)_m2(t)) or the st th signal(s) for transmission₁₁(t)) and a second th signal(s)₁₂(t)) of the base HF signal.

7. The method according to of the preceding claim, in particular according to of claims 2 to 6, wherein a th th signal or a th measurement signal(s) is transmitted_m1(t)) modulating the output of the generator (G11) according to the th signal, and sending a second signal or a second measurement signal(s)_m2(t)) according to the output of the second modulation generator (G12), or alternatively, the th signal(s) sent₁₁(t)) and a transmitted second th signal(s)₁₂(t)) or the th measurement signal(s)_m1(t)) and a second measurement signal(s)_m2(t)) from the output of the common modulation generator (G1).

8. method according to the preceding claim, wherein a signal(s) is generated for transmission₁₁(t)) and/or a second th signal(s)₁₂(t)) and then modulating the corresponding transmitted signal with a modulation generator, in particular a vector modulator, wherein the transmitted st th signal(s)₁₁(t)) and/or a second th signal(s)₁₂(t)) is preferably generated by applying a modulation signal to the real or complex input of a modulation generator, in particular a vector modulator, preferably in such a way that the signal(s) is added to the transmitted st nd th signal(s)₁₁(t)) generates a transmitted, preferably mirrored, second signal(s)₁₂(t))。

9. method according to the preceding claim, wherein the signal(s) is measured from the th measuring point_m1(t)) and/or the second measurement signal(s)_m2(t)) deriving a frequency, in particular a beat frequency, preferably containing time-of-flight information; and/or measuring the signal(s)_m1(t)，s_m2(t)) or a signal derived from the measurement signal or parts thereof, in particular the respective frequencies (preferably containing time-of-flight information), preferably the beat frequencies, are combined, preferably added, to one another.

10. The method according to of the preceding claim, in particular according to of claims 2 to 9, wherein the th measurement signal(s) is generated by a th mixer (M11)_m1(t)) and a second measurement signal(s) is generated by a second mixer (M12)_m2(t)), or, alternatively, a th measuring signal(s) is generated by a common, in particular complex, mixer (M1)_m1(t)) and a second measurement signal(s)_m2(t))。

11. method according to the preceding claim, wherein the measurement signal is an FMCW signal, in particular an FMCW ramp, a mixed product of SFCW signals or OFDM signals, preferably generated with uncorrelated local oscillators, in particular with a th local oscillator in the th transceiver unit and a second local oscillator in the second transceiver unit.

12. Method according to of the preceding claim, wherein the clock offsets of the transmitting and receiving units are determined by comparing the measurement signals and/or the synchronization of the transmitting and receiving units is carried out by a temporal variation of the clock offsets.

13. Device for compensating noise, in particular phase noise or system deviations, in a secondary radar system, preferably a radiolocalization system, having an uncorrelated th and second transceiver unit, in particular for carrying out the method according to of the preceding claim,wherein at least of the th transmitting/receiving units are used for generating and transmitting th th transmitting signals with th th interference components caused by noise or system deviation(s)₁₁(t)) and for generating and simultaneously or temporally overlapping transmitting at least second transmission signals(s) having a second interference component caused by noise or system offset₁₂(t)), the at least st th transceiver unit being designed such that, when the transmitted signal is reprocessed and evaluated, the phase and/or frequency shift caused by the interference component can be at least partially compensated.

14. The device according to claim 13, having a measurement signal generating device which is designed such that the th measurement signal(s)_m1(t)) from the transmitted st th signal(s) from the second transceiver₁₁(t)) and a received th second signal(s)₂₁(t)) is generated, in particular, by mixing, preferably in the form of complex conjugate multiplication, and/or the second measurement signal(s) is generated_m2(t)) from the second transmitted signal(s) from the second transceiver unit₁₂(t)) and a received second signal(s)₂₂(t)), in particular by mixing, preferably in the form of a complex conjugate multiplication.

15. The device according to claim 14, wherein the th measurement signal(s)_m1(t)) th interference component and the second measurement signal(s)_m2(t)) are complex conjugated to each other.

16. apparatus as claimed in any of claims 13 to 15, wherein the transmitted signal has a factor of , the factor of being related to the second transmitted signal(s)₁₂(t)) complex conjugate by a second factor.

17. an apparatus as claimed in any of claims 13 to 16, having a st transceiver, the th transceiver being for

Sending st thSignal(s)₁₁(t)) and a second th signal(s)₁₂(t))，

Receiving the transmitted th signal(s)₂₁' (t)) as a received th second signal(s)₂₁(t)) and a transmitted second signal(s)₂₂' (t)) as a received second signal(s)₂₂(t))，

Preferably, the transmitting and receiving apparatus has a transmitting antenna (TX) and a receiving antenna (RX) such that the transmitting antenna (TX) transmits the st nd signal and the second th signal and the receiving antenna (RX) receives the received th signal and the second signal, or

Preferably, the transmitting and receiving devices have a common transmit receive antenna (TX/RX) such that the common transmit receive antenna (TX/RX) transmits the st th signal(s)₁₁(t)) and a second signal(s) to the received th signal₂₁(t)) and transmits a second th signal(s)₁₂(t)) and to the received second signal(s)₂₂(t)) receiving.

18. apparatus according to claims 13 to 17, wherein, inter alia, there are or more mixers (M11, M12; M21, M22; M1, M2; M_RXTM) measuring signal generating device for generating a th measuring signal(s) from a transmitted th th signal and a received th second signal, in particular by mixing_m1(t)), and is designed to generate a second measurement signal(s) from the transmitted second signal and the received second signal, in particular by mixing_m2(t))。

19. apparatus according to claims 13 to 18, wherein the measurement signal generating device has a th measurement signal generating unit, in particular a th mixer (M1), and a second measurement signal generating unit, in particular a second mixer (M2), wherein the th measurement signal generating unit generates the th measurement signal, in particular by mixing, and the second measurement signal generating unit generates the second measurement signal, in particular by mixing(ii) a Alternatively, the measurement signal generating devices have a common measurement signal generating unit, in particular a common mixer (M)_RXTX), wherein a common measurement signal generation unit generates, in particular by mixing, the th measurement signal and, in particular by mixing, the second measurement signal.

20. an apparatus according to any one of the preceding claims 13 to 19, characterized by a HF generator (LO1), the HF generator being arranged to generate a signal(s) for the th measurement signal(s)_m1(t)) and a second measurement signal(s)_m2(t)) or the st th signal and the second th signal for transmission.

21. an apparatus according to any of the preceding claims 13 to 20, characterized in that the th modulation generator (G11) and the second modulation generator (G12) send th th signals(s)₁₁(t)) or the th measurement signal(s)_m1(t)) a second signal(s) transmitted in accordance with the output of said th modulation generator₁₂(t)) or a second measurement signal(s)_m2(t)) depending on the output of said second modulation generator, or a common modulation generator (G1) transmitting a th signal(s)₁₁(t)) and a second th signal(s)₁₂(t)) or the th measurement signal(s)_m1(t)) and a second measurement signal(s)_m2(t)) from the output of the common modulation generator.

22. Use of the method of claims 1 to 12 and/or the device of of claims 13 to 21 for increasing the accuracy of distance measurements and/or for safety-relevant applications and/or for compensating interference effects on the basis of simplified hardware, for example for generating local oscillator signals by means of a PLL and/or for evaluating the signal phase for estimating the velocity, for angle estimation and/or for SAR processing.

23. Radar system, in particular secondary radar system, designed for carrying out the method according to of claims 1 to 12 and/or having the device according to of claims 13 to 21 and/or for use according to claim 22, wherein the radar system has an uncorrelated and at least second transceiver units.

Technical Field

The invention relates to a method and a device for compensating interference effects, in particular phase noise, in a secondary radar system, in particular a radio positioning system.

Background

Secondary radar systems or systems for radio positioning are known in principle, they may have a system comprising at least two spatially separated non-correlated transmit-receive units NKSE1, NKSE2 with local oscillators LO1, LO2 and mixers Ml, M2 (see fig. 1), respectively, based on (non-correlated) local oscillators L1, L2 (due to the spatial separation of -based transmission lines, usually air transmission lines), it is in principle not possible to make distance measurements on the side with the accuracy of the main radar.

The secondary radar method is explained next (refer to fig. 1, where τ is the channel transit time). The baseband signal of NKSE1 or NKSE2 obtained after the mixing process can be passed through

In which A is₁Describing the amplitude of the signal,a phase curve of the effective signal is described,

uncorrelated phase noise (statistically independent in NKSE1 and 2) is described and

describing the correlated phase noise (in the same way as in NKSE1 and 2), in the embodiment of such an uncorrelated radar system known from DE 102014104273 a1, the synthesized measurement signal is generated by multiplication in the spectral range, which requires the raw data of the two stations to be transmitted to or a central computing unit of the two NKSEs.

The signal thus obtained corresponds in principle to the response of the main radar.

The resultant measurement signal

Is characterized in that the influence of the associated phase noise can be compensated. Said influence constitutes a significant contribution to the degradation of the signal quality and, if possible, to the allowance of only relevant measurements, only limited. The relevant signal sequences are required, for example, for a velocity estimation, for (backward) synthetic aperture radars or for an angle estimation by means of holographic reconstruction.

Furthermore, the amount of data obtained by analog-to-digital conversion is relatively large, and therefore an efficient data transmission method is required in order to calculate the raw data of two stations at sites.

A radar system is known from DE 102014104273A 1, in which the data scanned by the A/D converter after the mixing process are transmitted from units to another units (NKSE1 and NKSE2) or to a central computing unit, where the two units can be transmitted at the same time via the same mutual radio channel in a full-duplex manner, so that the phase noise (also referred to as beat signals) of the two mixed signals is correlated in the intermediate frequency (ZF). after the combined mixing of these beat signals, the influence of the phase noise and the influence of the interference caused by the systematic deviation in the signal generation/scanning can be suppressed relatively strongly, which in particular allows a correlated measurement or compensation of the uncorrelated phase noise and the interference quantities in the two NKSEs.

Overall, the accuracy of the measurement is regarded as worthwhile to be improved in known secondary radar systems, in particular in distance measurements.

Disclosure of Invention

The object of the present invention is to provide a method and a device for compensating for noise, in particular phase noise or system deviations, in a secondary radar, in particular a radio positioning system, which allow a higher accuracy in the measurement (in particular distance measurement).

This object is achieved in particular by the independent claims.

In particular, the object is achieved by a method for compensating noise, in particular phase noise or system deviations, in a secondary radar system, in particular a radio positioning system, having an uncorrelated th and at least second transmit-receive units, wherein a th th transmit signal having a 1 st 2 th interference component caused by noise or system deviations is transmitted by a 0 th transmit-receive unit, wherein at least second th transmit signals having a second th interference component caused by noise or system deviations are transmitted by a th transmit-receive unit simultaneously with or overlapping in time with a th th transmit signal, the transmit signals being preferably arranged such that, when the transmit signals are reprocessed and evaluated, a phase shift and/or a frequency shift caused by the interference component is at least partially compensated.

Preferably:

transmitting (simultaneously or overlapping in time) a th second signal and at least second signals(s) by means of a second transceiver unit₂₂'(t))，

Receiving the transmitted second signal as a received second signal and the transmitted second signal as a received second signal through an th transmitting-receiving unit,

the th measurement signal is generated from the transmitted th signal and the received th second signal, in particular by mixing and/or by correlation, preferably complex conjugate multiplication, and the second measurement signal is generated from the transmitted th signal and the received second signal, in particular by mixing and/or by correlation, preferably complex conjugate multiplication.

An (optionally independent) aspect of the invention is that not only the st transmission signal or the th measurement signal, but also (at least ) transmitted second signals or second measurement signals are generated, which are arranged such that a phase shift caused by (phase) noise or system movements and/or a frequency shift of (measurement frequency, in particular mixing frequency or beat frequency) is at least partially cancelled.

With a particularly adapted signal shape, data transmission as in the prior art can be superfluous if necessary. Furthermore, the remaining part of the (phase) noise can also be additionally suppressed (correlated contribution of the phase noise). This makes it possible to impose lower requirements on the quality of the components used for generating the high-frequency carrier signal if necessary. Furthermore, the phase noise level in particular does not form a lower limit for the accuracy of the radar measurement (in particular the distance measurement). It is also possible to utilize spatially distributed transmit and receive antennas, especially when transmission takes place over the same radio channel (especially because (contrary to known solutions) mutual transmission channels are not mandatory).

The measurement signal is understood to mean, in particular, a mixed signal derived from the transmitted signal of (for example st transceiver) of the transceivers and from the signals received by the transceiver (for example st transceiver) from another transceivers (for example second transceivers), such a mixture may be, in particular, a complex conjugate multiplication of the transmitted signal of the (transceivers) and the signals received by another transceivers.

Overall, the method enables, in particular, an effective reduction or (complete) suppression of (correlated) phase noise and/or system deviations. This can improve the accuracy of the distance measurement in a radio positioning system, for example.

The th interference component of the th measurement signal and the second interference component of the second measurement signal are preferably complex conjugates of one another, so that an effective reduction (or complete suppression) of noise, in particular (correlated) phase noise, can be carried out in a particularly simple manner.

The transmission of the second signal is preferably carried out simultaneously or at least overlapping in time with the transmission of the 0 signal, the transmission of the second signal is preferably carried out simultaneously or overlapping in time with the transmission of the 1 second signal, the overlapping in time being understood in particular to mean that at least 2 of the second 6 or second signal are transmitted during 20%, preferably 50%, of the signal duration of the transmission of the 3 43 or 5 second signal, the transmission of the second signal and of the second signal is preferably carried out overlapping in time with the transmission of the and second signals, the overlapping in time being understood in particular to mean that the second and/or second signal are also transmitted at least during 20%, preferably 50%, of the signal duration of the transmission of the and/or second signals.

The transmitted st signal preferably has at least a st th factor, which th factor is complex-conjugated with the second factor of the transmitted second signal, as a result of which an effective reduction (suppression) of (phase) noise can be carried out in a particularly simple manner.

In preferred embodiments, the signal transmitted comprises at least frequency ramps with a slope and the second signal transmitted comprises at least frequency ramps with a second slope, wherein the slope has a different sign than the second slope, wherein the magnitude of the and of the second slope is preferably (at least substantially) identical.

The basic HF signals for the th and second measurement signals (or for the transmitted th th and second th signals) are preferably generated by the same th HF generator.

Generally, the transmitted st (or th second) signal and the second (or second) signal are preferably arranged such that they have associated phase noise.

The basic HF signal is understood to mean, in particular, a high-frequency signal which comes (directly) from the output of a corresponding generator (oscillator). The base HF signal can then be subsequently modulated if necessary.

The base HF signal and/or the transmitted signal may have a frequency of at least 100MHz or at least 1 GHz.

Preferably, the transmitted th signal or th measurement signal is dependent on the th modulation generator output and the transmitted signal or second measurement signal is dependent on the second modulation generator output alternatively, the transmitted th th and second th signals or the th and second measurement signals may be dependent on a common modulation generator output.

The transmitted st signal may correspond to th/output of the th modulation generator the transmitted second signal may correspond to the output of the second modulation generator.

As long as a common modulation generator is used, signals generated by means of Direct Digital Synthesis (DDS) can be used in particular.

Preferably, (base) signals for the st signal and/or the transmitted second signal are generated (at a relatively low frequency) and the respective transmitted signals are then modulated by means of a modulation generator, in particular a vector modulator, wherein the transmitted st th and/or second th signal is preferably generated in such a way that the modulation signal is preferably applied to the real or complex input of the modulation generator, in particular the vector modulator, in such a way that the transmitted, preferably mirrored, second th signal is generated in addition to the transmitted st signal.

Alternatively or additionally, the measurement signals or the signals derived from the measurement signals or parts thereof, in particular the corresponding frequencies (preferably comprising time-of-flight information), preferably the beat frequencies, are combined, preferably added, with one another.

Preferably, the th measurement signal is generated by the th mixer (in particular by complex conjugate multiplication) and the second measurement signal is generated by the second mixer (in particular by complex conjugate multiplication). alternatively, the th measurement signal and the second measurement signal may be generated by a common, in particular complex, mixer (in particular by complex conjugate multiplication). in each case, a measurement signal having the desired properties can be generated in a simple manner.

In various embodiments, the measurement signal may be a mixed product of an FMCW signal, in particular an FMCW ramp, an SFCW signal (where SFCW stands for stepped frequency continuous wave) or an OFDM signal (where OFDM stands for orthogonal frequency division multiplexing). These signals are preferably generated using a (common) local oscillator.

The clock offsets of the transmitting and receiving units are preferably determined by comparing the measurement signals, a synchronization of the transmitting and receiving units can be carried out by a temporal course of (the stated) clock offsets, as a result of which accurate measurements, in particular distance measurements, can be carried out in a simple manner.

The above object is achieved, in particular, by an apparatus for compensating noise, in particular phase noise or system deviations, in a secondary radar system, preferably a radio positioning system, having an uncorrelated th and second transceiver unit, in particular for carrying out the method according to of the preceding claim, wherein th th transmit signals for generating and transmitting 0 th th interference components caused by noise or system deviations and at least th th transceiver units for generating and simultaneously or temporally overlapping at least second transmit signals having second interference components caused by noise or system deviations are formed, preferably so that, in the reprocessing and evaluation of the transmit signals, the phase and/or frequency shift caused by the interference components is at least partially compensated.

The device preferably has a measurement signal generating device which is designed such that the th measurement signal is generated from the th th signal transmitted from the second transceiver unit and the th second signal received from the second transceiver unit, in particular by mixing, preferably complex conjugate multiplication, and/or the second measurement signal is generated from the second th signal transmitted from the second transceiver unit and the second signal received from the second transceiver unit, in particular by mixing, preferably complex conjugate multiplication.

Preferably, the th interference component of the th measurement signal and the second interference component of the second measurement signal are complexes of conjugates with each other.

The apparatus preferably has a transceiver for transmitting the st nd and second th signals and for receiving the transmitted th signal as a received th signal and the transmitted second signal as a received second signal.

The th transceiver unit preferably has a transmit antenna and a receive antenna such that the transmit antenna transmits the th th signal and the second th signal and the receive antenna receives the th and second signals received alternatively, the transceiver unit may have a common transmit receive antenna, wherein the common transmit receive antenna transmits the th th signal and receives the th second signal received and transmits the second th signal and receives the second signal received.

The measurement signal generating device has in particular or more mixers.

Furthermore, the measurement signal generating device can be designed to generate a measurement signal from the transmitted th signal and the received th second signal, in particular by mixing (preferably by complex conjugate multiplication), and/or to generate a second measurement signal from the transmitted second signal and the received second signal, in particular by mixing (preferably by complex conjugate multiplication).

Preferably, the measurement signal generating device has an th measurement signal generating unit, in particular an th mixer, and a second measurement signal generating unit, in particular a second mixer, wherein the th measurement signal generating unit generates, in particular, a th measurement signal by mixing (preferably by complex conjugate multiplication), and the second measurement signal generating unit generates, in particular, a second measurement signal by mixing (preferably by complex conjugate multiplication). alternatively, the measurement signal generating devices may have a common measurement signal generating unit, in particular a common mixer, wherein the common measurement signal generating unit generates, in particular, a th measurement signal by mixing (preferably by complex conjugate multiplication) and, in particular, generates the second measurement signal by mixing (preferably by complex conjugate multiplication).

Preferably, the device has an th HF generator for generating a basic HF signal for the th and second measurement signal or for the th th and transmitted second signal.

In embodiments, the apparatus has an th modulation generator and a second modulation generator, the transmitted th th signal or th measurement signal is dependent on the output of the th modulation generator, and the transmitted second th signal or second measurement signal is dependent on the output of the second modulation generator.

The above-described object is further solved, inter alia, by a method of the above-described type and/or by the use of an apparatus of the above-described type for increasing the accuracy of distance measurements and/or for safety-relevant applications and/or for compensating interference effects on the basis of simplified hardware, for example for generating a local oscillator signal by means of a PLL and/or for evaluating the signal phase for estimating the speed, for angle estimation and/or for SAR processing.

The object is further achieved by radar systems, in particular secondary radar systems, which are designed to carry out the method described above and/or have an arrangement of the type described above, wherein the radar system has and at least (non-relevant) second transmitting and receiving units.

The method or the corresponding device according to the invention, in particular for compensating (phase) noise or system deviations, can be used in the method according to DE 102014104273A A1 (subsequently referred to as method I or configuration I) or in the method or configuration according to the not yet published german patent application with application number 102016100107.4 and in the corresponding international patent application with application number PCT/EP2017/050056 (subsequently method II or configuration II), method II or configuration II being a further step of method I or configuration I.

DE 102014104273 a1 and the yet unpublished patent applications DE 102016100107.4 and PCT/EP2017/050056 are to be understood as forming part of the present application (in particular with regard to the method on which the method according to the invention for compensating (phase) noise or the corresponding device can be used).

In particular, the method according to the invention and the corresponding device for compensating for (phase) noise or system deviations can be used in a radar system, wherein in /the (uncorrelated) th transmitting and receiving unit a signal is generated and transmitted, in particular transmitted, over a path, in a further , in particular a second/second transmitting and receiving unit a further signal is generated and transmitted, in particular transmitted, over a path, in an evaluation device, in particular in an transmitting and receiving unit, a signal of the transmitting and receiving unit is formed by a signal and a signal received over a path by the further transmitting and receiving unit forming a comparison signal, and in the evaluation device, in particular in the further transmitting and receiving unit, a signal of the further 360 transmitting and receiving unit and a signal of the further signal configuration formed by such a 363 signal of the further transmitting and receiving unit by such a further signal configuration can be used in a comparison, in particular, in a complex signal processing or comparison, in a further evaluation device, in which a complex signal is formed by a comparison between the second signal, in which a further signal is preferably formed by a complex signal is generated by a comparison, or a comparison signal is used in a comparison between the second transmitting and a further signal processing step of the second signal, wherein the comparison signal, a comparison signal is used in which a comparison signal is formed by the comparison signal is used in a comparison system or a comparison, or a comparison signal is formed by a comparison signal processing step of a comparison between the comparison of the second transmitting and a second signal processing step of the evaluation device, wherein the comparison of the comparison.

The (uncorrelated) second transceiver unit can in principle be constructed analogously to the (uncorrelated) th transceiver unit and optionally generate a third measurement signal (mixed signal) analogously to the th measurement signal (mixed signal) and a fourth measurement signal (mixed signal) analogously to the second measurement signal (mixed signal).

An uncorrelated transmitter-receiver unit is understood to mean a transmitter-receiver unit which transmits signals which are uncorrelated with respect to the signals of another transmitter-receiver units (even if the signals of the st transmitter-receiver unit or the another transmitter-receiver unit are themselves correlated).

For example, the respective transceiver unit can be designed as an arrangement of, in particular, or more antennas, comprising smaller signal-generating or signal-processing components, while other components, such as a signal comparison unit or an evaluation device, are connected to such an arrangement as structurally independent components.

The evaluation device can be an integral part of or more (two) transceivers or be connected to or more (two) such transceivers, if appropriate, physically separate evaluation devices can be provided, which are connected to the respective transceiver or to the remaining components of the respective transceiver, or alternatively, the evaluation devices can be integrated, if appropriate, for example in a common housing and/or as structural units into and/or another (non-relevant) transceiver.

Drawings

The embodiment is explained next in with the aid of the drawing.

Showing:

fig. 1 shows a secondary radar comprising two uncorrelated transmit receive units;

fig. 2 shows a schematic configuration of a radar system according to the present invention;

fig. 3 shows a graph of the course of the frequency of the signal used as a function of time;

FIG. 4 shows a schematic representation of alternative embodiments for a radar system according to the invention, and

fig. 5 shows a schematic illustration of another alternative embodiments for a radar system according to the invention.

Detailed Description

In the following description, the same reference numerals are used for the same and identically functioning components.

The signals are distinguished in particular in that the frequency shift by the (phase) noise is (exactly) opposite to the frequency shift by the (phase) noise of the further signals (which may correspond, for example, to conventional FMCW signals; if appropriate only with frequency ramps), the signals are furthermore preferably transmitted and received simultaneously (at least overlapping in time).

Fig. 2 shows a schematic diagram of possible configurations, in which two signals (s11(t) and s12(t) or s21(t) and s22(t)) are generated in the respective NKSE1 or NKSE2 from the same beat source LO1 or LO2, which includes modulation generators G11 and G12 or G21 and G22, it is alternatively also possible to use a modulator of only per NKSE, for example by means of Direct Digital Synthesis (DDS), which results in the two transmitted signals being influenced in opposition by a noise contribution (in particular phase noise through an FMCW ramp or non-linearity occurring in the same shape), a mixing process with a mixer M11 or M12 (or likewise with mixers M21 and M22 on NKSE2) generates in principle two signal components, of which have a relatively low beat frequency for the detection of the relevant signal components and can be separated from the high-frequency contributions, for example by means of a hardware and/low-pass filter implemented in software.

Fig. 3 shows the temporal course of the transmitted and received signals. Here, s11(t) and s12(t) describe signals transmitted simultaneously by NKSE1, or s21(t) and s22(t) describe signals transmitted (simultaneously) by NKSE2 received by NKSE 1. Signals s12(t) and s22(t) are characterized by frequency ramps having a positive slope. The comparison signals s11(t) and s21(t) are characterized by a negative slope of the frequency ramp with respect to time. For the following explanation it is assumed that the distance to NKSE2 should be determined at NKSE 1. This in principle requires only the transmission of a signal from NKSE2 to NKSE1, but not vice versa. Similar to this specification, NKSE2 may also (if necessary separately) determine the distance to NKSE1 if NKSE1 transmits the signal. When signals are transmitted in two NKSEs, the distance estimation can be performed simultaneously in two transmit-receive units. Furthermore, it should be assumed first that the two stations are synchronized in time.

It should furthermore be assumed that the two stations are presynchronized in Time, for example Using the method in US 7940743 or as described in precision Distance and Velocity Measurement for Real Time positioning in multiprocess environment Using a Frequency-Modulated Continuous-Wave radar radio access, s.roehr, p.gulden, m.vossek, 2008. This presynchronization is mainly used to ensure that the relevant signal components remain in the baseband after the low-pass filtering. Accurate synchronization can also be achieved by compensating the beat source, but also by post-processing and correcting the received signal in the manner described below.

In general, the change process in fig. 3 only functions as a possible embodiment, so that a time-shifted (for example, starting at Ts/2) part of the signal profile can also be selected if necessary, alternatively, the start frequency can also be provided with an offset B or-B for the two ramps in order to prevent the crossing of the two ramps, a conceivable implementation can also be the simultaneous use of a plurality of frequency ramps or a plurality of comparison signals at NKSE1 and/or NKSE 2.

The signals shown in fig. 2 and 3 and transmitted by NKSE2 can (assuming complete time synchronization first) be passed through

And

description, wherein B gives the bandwidth used by the radar system, f_c2Given the carrier frequency of NKSE2,

gives the phase noise of the local oscillator LO2, and μ ═ B/T_sThe scan rate (i.e., frequency increase per time unit) is given. Signal s received at NKSE1₂₁(t)＝As′₂₁(t-t) and s₂₂(t)＝As′₂₂(t- τ) is here treated as an attenuated and time-shifted version of the signal transmitted by NKSE 2.

Two linear frequency modulated signals

And

dependence on carrier frequency f on NKSE1_c1Phase noise of local oscillator LO1

And the size defined above.

The mixing product is generated after the mixing process and low-pass filtering (preferably implemented by the hardware of the measurement system in order to reduce thermal noise and interference with other radio applications) of the signal received by NKSE1 with the locally generated signal

And

in systems with real-valued scanning, the description of the complex number of the mixed signal can also be made via the Hilbert transform after digitization.

A complete calculation of the mixing product can be obtained as follows.

For s_m1(t) argument Φ_m1(t) gives:

for s_m2(t) argument Φ_m2(t) gives:

the addition of two signal shapes results in a signal with a resulting argument phi_msyn(t) composite mix signal:

Φ_msyn(t)＝2π{2μτt+Bτ-μτ²}

quadratic terms can be generally ignored here, in particular in narrow-band radar systems with a relatively slow FMCW chirp and an operating range of several hundred meters, since μ τ²Suitable is < B tau.

Thus, the two mixed signals have a positive frequency component dependent on the transit time.

In this regard, two beat frequencies can be determined (calculated) (by differentiation)

And

they are subject to statistical deviations by the correlated noise contribution δ f (t) and the deterministic frequency shift Δ f (caused by the different carrier frequencies at NKSE1 and NKSE 2). Complex conjugate phase curve based on a mixed signal, signal f_b11(t) is shifted to higher frequencies by these two components and the signal f_b12(t) to a lower frequency if the two quantities have positive values.

By summing, a resultant measuring signal is then obtained, which has a measuring frequency

f_b(t)＝f_b11(t)+f_b12(t)＝2μτ

It no longer has a correlation with the associated phase noise δ f (t) and the frequency shift Δ f. The result can be solved for τ and by the propagation velocity c with the electromagnetic wave (usually in air)₀Is x/c₀To estimate the distance between NKSE1 and NKSE 2. Based on the linear relationship, the detection of multiple objects, i.e. the reception of multiple time-shifted and attenuated replicas (superposition or linear combination of target responses) of the transmitted signal, can be carried out.

The phases of the two mixed signals can be grouped as follows:

two time signals s can follow_m1(t) and s_m2(t) Fourier transform of

Wherein, is configured of phi₂(t) ═ 2 π μ τ t and Φ₃Application to-pi B tau (term mu tau)²/2 is negligibly small according to the above assumptions). Phi₁(t) contains all residual components whose phase shift is at s_m1(t) and s_m2(t) are complex conjugated with each other. The signal Sm1(f) is at an abscissa value f in the frequency range_max，1Δ f + μ τ + δ f (t) has a maximum value by number, and S_m2(f) At f_max，2If the phase values of the two signals, which are associated with a maximum value, are now determined, the aspect yields ψ_max，1(t)＝Φ₁(t)+Φ₃And another aspect produces psi_max，2(t)＝-Φ₁(t)+Φ₃Wherein the sum of the phase values ψ₀＝ψ_max，1(t)+ψ_max，2(t)＝2Φ₃Providing a synthetic phase

ψ₁＝ψ_max，1(t)+ψ_max，2(t)＝-2πBτ。

The phase value can thus be determined, which is proportional to the distance value or the channel transit time. The phase deviation of the synthesized mixed signal depends in this case only on the thermal noise, but not on the phase noise of the local oscillator used. It is therefore particularly advantageous for accurate distance estimation that the resultant mixture product f_b(t) and also the determined phase of the resulting signal₁The closed calculation of (2).

If a time shift T occurs with respect to the starting time point of the FMCW sequence₀The resulting mixing frequency f is known from WO 2010/019975A 1_b(t)＝2μ(τ-T₀) In NKSE1 and f_b2(t)＝2μ(τ+T₀) Produced in NKSE2And (4) generating. Unknown time shifts can thus be corrected by mutual calculation (or addition). This is advantageously also possible by means of the detected phase deviation using the signal shape, since ψ is found at NKSE1₁＝-2πB(τ-T₀) Applicable and applicable at NKSE2 psi₂＝-2πB(τ+T₀) The method is applicable. The phase shifts of the determined phase values relative to one another are thus linearly dependent on the transit time τ and the time shift T0 in the channel. The occurring deviations can be determined and corrected by subtraction. Alternatively, the estimated values for the distance or the channel transit time can also be determined directly by addition. Furthermore, the synchronization method does not require simultaneous transmission and reception (duplex operation) of two stations, but can be performed sequentially.

Particularly advantageously, the phase estimate ψ₀Can be influenced by the variation of the starting frequency of the FMCW chirp, i.e. the parameter B, since it changes the phase deviation of the two mixed signals from one another depending on the quality of the presynchronization. This temporal synchronization can also be implemented by a change in the starting frequency of the up and down sweeps. Very accurate synchronization is achieved with a starting frequency that is far apart from each other, i.e. a high "distance" B of the two FMCW ramps.

Fig. 4 shows a circuit diagram of a system of embodiments comprising complex mixers and an up-conversion in the transmit branch the block circuit diagram shown in fig. 2 contains two real-valued mixers which can be used for the separation of the up-and down-scanning and which are also replaced by complex mixers (M in fig. 4)_RX1) It is likewise possible to replace the two modulation generators G1 and G2 of NKSE1 in fig. 2 by (G1 in fig. 4) whose signals can then be replaced by a transmit mixer M_TX1Hybrid, where two transmit signals may constitute upper and lower sidebands. Furthermore, the mixing product of two low frequencies can be separated in a quadratic radar, preferably by a suitable choice of frequency or time shift between the two stations. In an advantageous alternative, the use of a complex mixer is not necessary, since the two mixing products occur at different positions in the frequency spectrum.

Fig. 5 shows a circuit diagram comprising a transmission mixer and an up-conversion in a transmission branch system, the embodiment according to fig. 5 comprises -only transmission and reception antennas instead of two separate transmission and reception antennas, which are used together for transmission and reception, for which purpose a transmission mixer TM can be used, which has advantageous transmission properties, in particular in an FMCW system.

In principle, the above-described method can also be used to suppress interference effects in order to reduce the hardware requirements (e.g. the quality of the phase adjustment loop) for low phase noise generation of the high-frequency carrier signal. The resulting error can be compensated for afterwards by said processing.

Next, further explains examples of applications of the present invention:

it is generally known that the accuracy of range estimation in radar systems increases as the signal-to-noise ratio (SNR) increases the inverse ratio of the signal power to the square of the range (in quadratic radar systems) constitutes a significant difference from the main radar system, since the SNR decreases with the fourth power of the range in the latter cases, furthermore no correlation by the mixing process (and thus no phase noise suppression) is carried out in the system, so that at sufficiently high signal-to-noise ratios (as independent as possible of range) phase noise often has a greater influence on the measurement accuracy than thermal noise.

For example, the invention can be used in industrial environments, for example for position determination on cranes, as landing aids, as positioning lighthouses, in container vehicles and/or in rail-bound or freely movable vehicles. This allows accurate positioning of the object, which can be used, for example, for process automation, for optimizing production or warehousing processes, and/or for collision avoidance. The localization can be carried out by means of 1D estimation, but also the distances between a plurality of distributed radar stations can be determined. In the case of 2D or 3D, the position in the plane (or space) can preferably be determined by means of multipoint positioning.

Another advantageous application of the method according to the invention is a system in which the generation of signals with relatively low phase noise (for example by means of an optimized phase control loop) is dispensed with, which signal generation represents a significant outlay in the manufacture in mobile radar units, which is reflected in increased hardware costs and increased energy requirements.

The embodiments shown in fig. 4 and 5 can be used to simplify the signal generation. In this case, the mirror frequency can advantageously be used as a comparison signal after high mixing. In a typical radar system, this must be suppressed at significant expense.

Another applications may be security-relevant applications, such as radio keys ("keyles Go"). possible forms of Attack on such systems constitute the so-called "Relay Attack" (which is implemented by a distant (radar station), where another users may actively insert into the session, in which case the FMCW signal is not only used for radar applications, but also for communication (real-time capable) third communication units may synthesize here lower distances, listen for communication and/or participate by frequency shifting of the local oscillator, which cannot be achieved due to the mere adjustment on the frequency of the moving local oscillator (especially in the signal variation curve shown in fig. 3).

The invention also makes it possible to determine phase values, which are proportional to the distance or the channel transit time. In this regard, in operation with a plurality of consecutive chirps (Chirp Sequence Radar), not only the distance of the target but also its velocity can be estimated using 2D-FFT. Here, the unambiguous range is related to the bandwidth B and not to the carrier frequency as in the primary radar system. Based on a well-defined (significant) amplification, less requirements can be placed on the temporal order of the individual FMCW chirps.

With the aid of phase detection, it is also possible to estimate the differential phase between a moving (uncorrelated) transceiver unit and a plurality of distributed (uncorrelated) transceivers, which optionally have fixed known positions in space. By means of the phase difference, the direction or elevation angle, or also the position, of the (non-correlated) transmitting and receiving unit relative to the movement can be determined. The information is particularly advantageous in connection with the application of holographic evaluation methods, since large apertures can be generated by the motion and angle or position estimation can be carried out very accurately (or with high resolution).

It is pointed out here that all the above-described components or functions are claimed as essential to the invention, viewed individually as such and in each combination, in particular in the details depicted in the drawing. Modifications thereto will be readily apparent to those skilled in the art.

List of reference numerals

G1 modulation generator

G11 modulation generator

G12 modulation generator

G2 modulation generator

G21 modulation generator

G22 modulation generator

LO1 No. local oscillator

LO2 second local oscillator

Ml mixer

M2 mixer

M11 mixer

M12 mixer

M21 mixer

M22 mixer

M_RX1(plural) mixers

M_RX2(plural) mixers

M_TX1Sending mixer

M_TX2Sending mixer

NKSE-independent transmitting-receiving unit

NKSE 1-unrelated th transmitting-receiving unit

Second transmitter-receiver unit with non-related NKSE2

RX1 receiving antenna

RX2 receiving antenna

s11(t) th th signal

s12(t) second Signal

s21' (t) second signal

s22' (t) second signal

TM1 transmission mixer

TM2 transmission mixer

TX1 transmitting antenna

TX1/RX1 transmitting-receiving antenna

TX2 transmitting antenna

TX2/RX2 transmitting-receiving antenna

Transmission channel