EP3589976A1

EP3589976A1 - Radar system and method for operating a radar system

Info

Publication number: EP3589976A1
Application number: EP18707358.0A
Authority: EP
Inventors: Martin Vossiek; Michael GOTTINGER; Peter Gulden
Original assignee: Friedrich Alexander Univeritaet Erlangen Nuernberg FAU; Symeo GmbH
Current assignee: Symeo GmbH
Priority date: 2017-03-02
Filing date: 2018-02-26
Publication date: 2020-01-08
Also published as: DE102017104380A1; US20200018840A1; WO2018158173A1; US11353570B2

Abstract

The invention relates to a radar system comprising: - at least a first (SE1) and a second (SE2) transmitting-receiving device with in each case at least one transmitting antenna and at least one receiving antenna as well as a HF generator, and - a common clock generator for the HF generators of the transmitting-receiving devices, wherein at least one evaluation device is provided, which is configured to process transmitting and receiving signals of the transmitting-receiving devices (SE1, SE2) to modified measurement signals with increased coherence.

Description

Radar system and method for operating a radar system

description

The present invention relates to a radar system and a method of operating a radar system.

In radar systems, there is a strong interest in reducing a measurement error of the angle measurement and an angular resolution, i. H. the ability to separate multiple targets across the angle to increase. An increase in the angle measurement accuracy and resolution is achieved quite significantly via an enlargement of the aperture of a radar antenna and a population of this antenna with as many transmit and receive paths (see Hardware Realization of a 2 mx 1 m Fully Electronic Real-Time mm-Wave Imaging System A. Schiessl, A. Genghammer, S. Ahmed, L. -P. Schmidt, EUSAR 2012, as well as BLASTDAR-A Large Radar Sensor Array System for Blast Furnace Burden Surface Imaging, D. Zank, et al., IEEE Sensor Jounal , Vol. 15, No. 10, Oct. 2015). This usually occurs at comparatively high transmission frequencies (eg 24 GHz, 61 GHz, 76-80 GHz, 122 GHz, 240 GHz and higher). At these high

Frequencies, the radar electronics is built on technically comparatively complex substrates. In addition, the distribution of signals with relatively high frequencies is associated with radiation losses and attenuation, which adversely affects a transmission power and a signal quality. Solution measures are technically complex and demanding in implementation.

It is therefore an object of the invention to propose a radar system and a corresponding method in which measurement deviations can be reduced in a simple manner and a comparatively good angular resolution can be achieved.

This object is achieved in particular by a radar system according to claim 1.

In particular, the object is achieved by a radar system, the at least one first and one second transceiver each having at least one transmitting and at least one receiving antenna, and an RF generator and a common clock generator for the RF generators of the transmitting Receiving devices comprises, wherein at least one evaluation device is provided, which is configured to process transmission and reception signals of the transceiver devices to modified measurement signals with increased coherence.

A core idea of the invention is to process transmit and receive signals of the transceivers using a common clock generator for the various RF generators in such a way that they have increased coherence (in the form of the modified measurement signals). A method for increasing the coherence for distributed radar systems is for example

DE 10 2014 104 273 AI known. DE 10 2014 104 273 A1 also describes a corresponding radar system. The method according to

DE 10 2014 104 273 A1 shall be referred to below as "method Γ. The configuration of the radar system according to DE 10 2014 104 273 AI should be referred to as "configuration Γ. Another method and a further configuration for a radar system to increase the coherence is described in the not yet published German patent application with the application number 10 2016 100 107.4 and the corresponding international patent application with the application number PCT / EP2017 / 050056. The method or radar system described in these two applications will hereinafter be referred to as "method II" and "configuration." Surprisingly, it has been found that such methods also increase the coherence in the case of Provide significant benefits to a common master clock system for different H F generators. In particular, it has been shown that a

comparatively high angular accuracy and a relatively good resolution can be achieved with simple means.

Basically, it has been recognized as desirable, all H F signals in a radar system (only) in an immediate environment of the transmitting and

To produce receive antennas, or to integrate the transmit and receive antennas already in a chip package or on the chip itself (see A 77-GHz SiGe single-chip four-channel transceiver module with integrated antennas embedded wafer-level BGA package, M Wojnowski, C. Wagner, R. Lachner;

J. Bock; G. summer; K. Press !; 2012). It can for the individual transmit and receive antennas, or for subgroups with multiple transmit and

Receiving antennas each have a separate generation of high-frequency transmit and receive signals are made. In addition, a current

Transmit signal mixed or correlated with received signals, so that only one or more low-frequency signals must be routed to a computing unit. Optionally, a digitization directly after the

Downmix or Correlate done. Furthermore, optionally a mixture or correlation (direct) can be done digitally.

According to one aspect of the invention, several H F generators (from a plurality of transceivers) are supplied from the same clock source. Through the use of suitable phase locked loops (phased-locked loop), H F signals which are coherent with one another can preferably be generated in the individual H F generators.

In addition, all H F signals have the same reference clock, d. H.

Noise components of a clock generator (such as phase noise of a quartz oscillator) equally affect the H F signals in all H F signals. As a result, the person skilled in the art initially expects a good functioning of such an arrangement. In practice, however, unexpected technical problems have emerged. It has now been recognized that these problems result from the use of independent RF oscillators (H F generators) and control loops in the signal generation paths. These can generate additional (independent) noise components in the H F signals, in particular phase noise components. Furthermore, the phase locked loops (PLLs) have different non-linearities due to component tolerances, which can also lead to systematic deviations. Thus, the mixed-down signals for signal components, which in a

Signal generator (RF generator) generated and received in another, additional noise and interference components on. This extra

Noise degrades the accuracy of the radar system and reduces dynamic range around (strong) targets, i. other (weaker) targets are obscured. According to the invention, these components are now solved by the use of a method for the subsequent generation of coherence. In particular, weaker targets can be separated from stronger targets, and in general the measurement accuracy and resolution are improved.

The first transceiver can be arranged with its (assigned) RF generator on a (common) board. Alternatively or additionally, the second transceiver with their

(assigned) RF generator on a (common, possibly further) board (chip) may be arranged. Likewise, the (common) clock and first transceiver, second transceiver (optionally with their respective associated RF generators) can be arranged on a common board (chip). In particular, transmitting and receiving antennas can already be provided in a preferably designed as a chip package corresponding transceiver or be integrated on a chip itself. As a result, measurement accuracy and resolution can be improved.

Preferably, the RF generators are in the vicinity of transmitting and

Receiving antennas of the transceivers arranged. An arrangement in the vicinity means, in particular, an arrangement at a distance of less than 20 mm, preferably less than 10 mm.

Preferably, the RF signals of the (individual) RF generators are at least partially coherent with each other. Further preferably, this is one

Phase locked loop (PLL) provided.

In this context, it has been shown that an increase in the coherence with the method I or method II, even with basically (partially) coherent RF signals, a significant gain in terms of the quality of the

Delivers results. The increase in coherence occurs in an embodiment according to the

Method I or in accordance with the configuration I. The transceiver units (SE) mentioned in DE 10 2014 104 273 A1 are preferably components of the transceivers of the present disclosure or

correspond to these (apart from the fact that the original signals in the present disclosure may possibly also be at least partially coherent with each other, so not necessarily non-coherent output signals in the sense of DE 10 2014 104 273 AI present). Preferably, in the first transceiver, a first signal is generated and transmitted over a path, in particular radiated, generated in the second transceiver, a further first signal and sent over the path, in particular radiated in the evaluation device, in particular in the a first comparison signal from the first signal of the first transceiver and from such from the second transceiver, over the path received, the first signal are formed, and in the evaluation, in particular in the second transceiver further comparison signal from the first signal of the second transceiver and from such from the first transceiver, over the path received, the first signal are formed, wherein the further comparison signal preferably from the second transceiver to the first transceiver transferred device, in particular is communicated. Further preferably, the system is

in particular the evaluation device for forming a comparison comparison signal from the first comparison signal and the other

Comparative signal configured. Further embodiments and specifications of method I can be found in DE 10 2014 104 273 A1, the disclosure of which is hereby incorporated by reference into a part of the present disclosure (in particular with regard to the methods described therein and

Configurations to increase or establish coherence).

In a particularly preferred embodiment, the configuration II or the method II is used to increase the coherence. The disclosure of the not yet published German patent application with the application number 10 2016 100 107.4 and the corresponding international patent application with the application number PCT / EP2017 / 050056, the methods II or

Describe configurations II, is hereby incorporated by reference DISCLOSURE OF THE PRESENT DISCLOSURE, IN PARTICULAR WITH RESPECT TO THE CONFIGURATIONS OR METHODS FOR INCREASING THAT CONCEPT. Preferably, the system, in particular the

Evaluation device configured to compensate in a first step deviations of the comparison signals, which are caused by systematic deviations in the transceivers, and in a second step, at least one complex value from a first of the two comparison signals or from a signal, the this first

Comparative signal has been derived to be used to adapt at least one complex value of the second of the two comparison signals or a value of a signal derived from this second comparison signal, and thus to form a matched signal, wherein the adaptation is done by a mathematical operation the vectorial sum or the

Difference of the complex values is formed, or the sum or the difference of the phases of the complex values is formed. With such a configuration (or a corresponding method) for increasing the coherence, particularly good results with regard to resolution and measuring accuracy can be achieved. In particular, with comparatively little

Computational effort (especially compared to method I or configuration I) to achieve a good result.

In an alternative embodiment, the (above) comparison comparison signal by the two comparison signals processed with each other - are multiplied complex, in particular conjugated complex -, correspond to a comparison signal generated with a coherent radar system.

Preferably, the transceivers are understaffed (in a sparse array). This further improves accuracy and target separation, in particular by providing side maxima (sidelobes) and the

Total aperture further optimized. A sparse array is to be understood in particular as an array in which a distance between the individual transmitting and receiving devices (antennas) is greater than λ / 2 (A = (average) wavelength of the transmitted signals).

Preferably, the first and / or the second transceiver has / have two or more transmitting antennas and / or two or more receiving antennas. The system, in particular the control device of the system, can do so

be configured that the transmitting antenna (s) of the first transceiver and the transmitting antenna (s) of the second transceiver transmit simultaneously or overlapping in time and / or that the transmission signals of the transmitting antenna (s) of the first and the transmitting antenna (s) the second transceiver differ from each other,

in particular have a frequency offset against each other and / or differ from each other by a pulse, amplitude and / or phase modulation. In particular, in a first step at least two different transmission paths S ITX and S2 _T x, which are fed by different H F generators, are fed (almost) simultaneously or overlapping in time. "Almost simultaneously" means in particular that the transmission signals S _{T T} x and S2 _T x are transmitted overlapping in time, at least for a large part of their signal duration (for example over at least 50% or at least 70% of the

Signal duration of S ITX). The transmission signals S ITX and S2 _T x can either have a frequency offset from each other, or otherwise

Distinction possibility, z. B. via a pulse, amplitude and / or

Have phase modulation. The signals received by each reception path then contain their own signals reflected by the environment and the signals of the second transmission path reflected by the environment.

Preferably, the system, in particular a control device (s) of the system, is configured so that received signals and the transmitted signal are mixed or correlated, wherein preferably then a separation of the received signals due to a distinguishing feature,

in particular a frequency offset against each other and / or a

discriminating pulse, amplitude and / or phase modulation of

Transmission signals to which the received signals are returned takes place.

Preferably, therefore, the received signals are down-mixed or correlated with a (local) H F signal. As a result, a low-frequency signal S eat arise that both components from the direct

Reflection path (own transmission signal), as well as the indirect reflection path (foreign transmission signal) has. Subsequently, a separation of the signals via a frequency difference or otherwise modulation can take place. The signals of the own reflection path can then be used as normal radar signals can be processed, the signals of the indirect path can be further processed if necessary.

The above object is further achieved by a method for operating a radar system, in particular as described above, wherein the radar system at least one first and one second transceiver each having at least one transmitting and at least one receiving antenna, and an RF Generator and a common clock for the H F generators of the transceiver devices, said transmit and receive signals of the transceiver devices are processed to modified measurement signals with increased coherence.

Preferably, in the first transceiver, a first signal is generated and transmitted via a path, in the second transceiver generated a further first signal and sent over the path, in particular radiated, a first comparison signal from the first signal of the first Transceiver device and from such from the second transceiver, over the path received, formed first signal, another comparison signal from the first signal of the second transceiver, and from such from the first transceiver, over the path formed, the further comparison signal is preferably transmitted from the second transceiver to the first transceiver, in particular, is communicated, and / or preferably a comparison comparison signal from the first comparison signal and the other

Comparative signal is formed and / or wherein in a first step

Deviations of the comparison signals, which are caused by systematic deviations in the transceivers compensated and used in a second step, at least one complex value from a first of the two comparison signals, or from a signal derived from this first comparison signal, at least to adapt a complex value of the second of the two comparison signals or a value of a signal derived from this second comparison signal, and thus to form a matched signal, the adaptation being such that by a mathematical operation the vectorial sum or the difference of the complex values is formed, or the sum or difference of the phases of the complex values is formed. Under high frequency (HF) is in particular a frequency of at least

100 MHz, preferably at least 1 GHz, more preferably at least 10 GHz to understand.

A path is in particular an (air) interface to understand, via which the corresponding signals (and possibly comparison signals) can be sent or transmitted and received by means of antennas.

An indirect path or a cross path is to be understood as the path of a signal which originates from one (for example the second) transceiver and is received by another (for example the first) transceiver. Accordingly, a direct path is to be understood as a signal that is both transmitted by the same transceiver and received as a reflected signal.

A non-coherent transceiver (or transceiver) is to be understood as a transceiver (transceiver) whose transmitted signal is non-coherent with respect to the signal of another transceiver (transceiver) is only partially coherent (compared to a signal with increased coherence) (even if the signal of the first transceiver / transceiver or the other transceiver / transceiver is inherently coherent).

As far as in the (respective) transceiver calculations,

Evaluations or other method steps are carried out, including an optionally physically independent evaluation, which is connected to the transceiver. By way of example, the respective transceiver device can thus be embodied as an arrangement of in particular one or more antennas with a few (few) signal-generating or

signal processing components to be formed while others

Components such as signal comparison units or an evaluation device can be connected as structurally independent component to such an arrangement. Insofar as components are used, they can be processed (so far technically feasible) as so-called hardware Be formed components and / or as a part or all in one

Processor executed signal or data processing steps are implemented.

In general, the evaluation device may be part of one or more transceivers, or may be connected to one or more such transceiver devices. Optionally, a physically independent evaluation device can be provided, which is connected to the respective transceiver or the other components of the respective transceiver. Alternatively, the evaluation device may possibly be integrated into the first and / or the second (generally further) transceiver device, for example in a common housing and / or as a structural unit.

In any case (irrespective of where specifically the

Evaluation device is arranged) that a cross path (indirect path) may arise, i. that a coverage of transmitting and receiving areas is provided accordingly.

In the following, the method II or the configuration II will be further described, wherein the (non-coherent) transmitting and receiving units are to be part of the transmission-receiving devices described further above (or to form them). The transceiver units are also abbreviated as SE.

According to the method II, signals transmitted between the SEs are processed in such a way that comparison signals arise which have advantageous properties which otherwise only have radar signals which are provided with only one common device for signal generation, ie with a coherent one

Signal source work. The subject matter of method II is, in particular, methods for reducing disturbing effects which are uncorrelated by the method

Phase noise of the multiple stand-alone devices for signal generation are caused.

Method II is particularly advantageously applicable to the transceiver devices according to the invention. In the field of radar signal processing one would like to convert the received signals to the lowest possible intermediate-frequency signal to a high

Achieve accuracy and long range. It can be assumed that there are several propagation paths between transmitter and receiver.

In principle, it is possible the received Mehrpfadausbreitungen and

Correlated noise components by bandpass filtering with a, exactly to the expected frequency, matched filter to suppress. In practice, however, this method is poorly practicable since synchronization errors of the sampling instants and the local oscillator frequencies in the respective SEs allow accurate prediction of the beat signals generated after the mixing process only to a limited extent. Due to these problems, the phase noise correlation of these two signals is reduced and the phase estimation error increases.

Advantageously, therefore, methods with calculation steps in which the effects of phase noise and synchronization errors are reduced or completely suppressed.

Method II begins with at least two SEs transmitting almost simultaneously. Almost simultaneously in this context means that the

Send signals sigTXl and sigTX2 at least for a large part of their

Signal duration in both directions, ie sigTXl be transferred from SEI to SE2 and sigTX2 from SE2 to SEI. The initially possibly unknown difference of the starting times of the transmission signals sigTXl and sigTX2 is designated as T_off. The aim should be as much as possible transmission times, the shift T_off should preferably not be greater than half the signal duration, but in any case less than the signal duration. Due to the at least partially independent generation, the signals sigTXl and sigTX2

uncorrelated signal components due to the phase noise of the signal sources in stations SEI and SE2.

In such an arrangement, preferably the same antennas for

Transmit (Tx) and receive (Rx) to ensure the reciprocity of the transmission channels. For arrangements in an array (eg MIMO) to ensure that preferably at least one of the transmission paths is reciprocal. Particularly suitable for achieving the reciprocity is the

Use of a transmission mixer in at least one transmission and

Receiving path of the SE. An exemplary realization of a

Transmission mixer in a radar arrangement is described for example in US

6,317,075 Bl executed.

As a further step then in each SE the comparison signals

(sigC21; sigC12) formed between the respective received signal and the transmission signal or with a with the transmission signal with respect to

Phase noise correlated proportion of the transmission signal. The procedure for

Formation of these comparison signals corresponds to the procedure in patent application DE 10 2014 104 273 AI.

According to the invention, phase noise and synchronization errors are then at least reduced by performing the processing of the received signals in two stages: As a first step, systematic deviations are corrected, either before the signals are received via an activation of the signal source, and / or via a compensation directly in the received signal and / or via a compensation in the comparison signal. As a second step, for example, a shortened evaluation of the correlation or the formation of a comparison comparison signal takes place only for the expected shift range or, in the best case, in only one shift value.

It is particularly advantageous in the second step, in process II different than in

DE 10 2014 104 273 AI implemented, no multiplication for phase compensation, but to use an addition of the complex signals. The use of the addition instead of the multiplication is by the first step of the processing described above, ie by the previous compensation of

systematic deviations possible.

A multiplication or division of the signals represents a non-linear operation. Non-linear operations always go with non-linear effects, so here in particular with so-called intermodulation of signal and Noise, accompanied. This results especially in radar signals with multiple signal components, ie signals that have multiple targets or more

Signal transmission paths include, to interference. The use of the addition of the complex signals proposed according to method II has the great advantage that the addition is a linear operation, whereby non-linear effects, that is to say in particular intermodulation of signal and noise components, are avoided. This embodiment therefore generally leads to a significantly better reduction of the phase noise in comparison to methods for combining the comparison signals sigC21 and sigC12.

As a result, in Phase II the phase noise / influence of the

Suppressed phase noise without the aforementioned additional interference occur, as would be expected in DE 10 2014 104 273 AI. In addition, this approach is technically advantageous since it requires significantly less computing than the embodiment described in DE 10 2014 104 273 A1

Proposed complete multiplication or correlation needed.

In order to be able to carry out the process according to method II, preferably a precise, either direct (via controllable hardware) and / or synthetic (computational) synchronization is carried out in order to obtain the

Frequency offset (as far as possible) to compensate. Then, a linearized approach can be used which will only cancel the correlated portion of the perturbation at low residual phase differences (principle shown in Figure 3).

The synchronization can be carried out separately before the measurement, as part of the measurement itself, or following the measurement. In a synchronization in the context of the measurement or subsequent to the synchronization, for example, via subsequent adaptation of the

Comparison signal done.

For synchronization, means or methods may be provided which are suitable for directly controlling the clock rates of the sources of sigTX1 and sigTX2 (eg using TCXO) or computationally (synthetic synchronization) to match.

All known methods for equalizing clock sources in distributed stations can be used. Particularly advantageous approaches to synchronization are methods according to US Patent 7,940,743, according to patent application

DE102008010536, or the exchange of reference clocks or reference signals. Another method of clock matching within measurements for FMCW signals will be described below.

All of these methods for equalizing the clock sources can be implemented either via radio waves or via cable connections. Wired may mean electrical signals or optical signals carried by cables.

Alternatively, or as an improvement to the methods for adjusting

Clock sources can also be very high-quality clock sources, for example

Atomic clocks, are used.

After the step of synchronization, signals (sigEP21, sigEP12) can be derived from the comparison signals, each of which represents a function having as a function argument the signal propagation time or the length of the transmission channel of the respective signal components.

The offset T_off between the stations is then determined, for example, by the methods disclosed in DE 101 57 931, or by a correlation of the comparison signals of the at least two SEs. The maximum can provide the offset. Alternatively, this can also be done below for FMCW signals

described methods are used. As before, the processes can be conducted by cable or by radio waves.

From the signal sigEP21 at least one function value Fl can be determined, which is to be assigned to a specific transit time, and at least one further function value F2 of the signal sigEP12, which is to be assigned to the same runtime as exactly as possible. Fl with F2 you will be charged. This calculation takes place, for example, by adding or subtracting the two

Runtime values.

This eliminates or at least reduces noise due to the non-correlated signal components of the signals sigTXl and sigTX2, which are due to the phase noise of the signal sources.

The steps of method II are summarized below:

Method for reducing phase noise interference in a radar system, in which

a first signal (sigTXl) is generated in a first (non-coherent) transceiver unit (SEI) and transmitted, in particular transmitted, over a path (SP),

in a further, in particular second (non-coherent) transceiver unit (SE2), a (further) first signal (sigTX2) is generated and transmitted via the path (SP), in particular emitted,

- the signals (sigTXl and sigTX2) are received in the respective other transceiver unit directly or indirectly, where they are further processed as received signals sigRX12 and sigRX21,

- In the first transceiver unit (SEI) a comparison signal (sigC12) from the first signal (sigTXl) and from such from the further transceiver unit (SE2) via the path (SP) received first signal (sigRTX2) is formed and

- In the further transceiver unit (SE2), a further comparison signal (sigC21) from the first signal (sigTX2) and from such from the first transceiver unit (SEI) via the path (SP) received first signal (sigTXl) is formed,

wherein the further comparison signal (sigC21) is transmitted from the further transceiver unit (SE2) to the first transceiver unit (SEI), in particular, is communicated,

- In a first step deviations of the signals sigC21 and

sigC12, which are caused by systematic deviations in the transceiver units (SE2, SEI), are compensated,

wherein, in a second step, at least one complex value from a first of the two comparison signals or from a signal derived from this first comparison signal is used for at least one complex value of the second of the two comparison signals or a value of a signal resulting therefrom second comparison signal has been derived, adapting and thus to form a (adapted) signal (sigCC),

- wherein the adjustment is made such that the vectorial sum or the difference of the complex values is formed by a mathematical operation or the sum or the difference of the phases of the

complex values is formed.

Embodiments will be explained in more detail with reference to FIGS. Show it:

1 shows two mutually communicating transceiver units and individual components thereof;

Fig. 2 shows the components of Fig. 1 with an illustration of a

Process flow;

Fig. 3 above Beat signals of the two transceiver units with uncorrelated noise before synchronization and below synthetic mixed product with correlated phase noise after synchronization;

4 spectrograms of all ramps from the two transmitters

Receiving units before synchronization;

5 shows a schematic representation of a conventional radar array;

6 is a schematic representation of a radar according to the invention

arrays;

Fig. 7 is a phase noise diagram; and

Fig. 8 is a schematic representation of direct and indirect signal paths.

As can be seen from FIG. 1, two transceiver units SEI, SE2 communicate with one another via a radio interface. In this case, a first or a second signal sigTXl, sigTX2 are sent. The transceiver units SEI, SE2 each have a signal source 1, a clock adaptation unit or

Comparison signal modification 2 and a transmission comparison unit (SigCompl, SigComp2). The (non-coherent) transceiver units preferably form transceiver devices. Thus, in the following, SEI can be regarded as a first transceiver and SE2 as a second transceiver.

FIG. 2 additionally shows a unit for phase modification 4 in each case. A data exchange takes place between the two units for phase modification 4.

In the following, the exact mathematical derivation of the method of operation II is carried out. In a first (non-coherent) transceiver unit (SEI), a first signal (sigTXl) is generated and transmitted via a path (SP), in particular emitted. In a further, in particular second (non-coherent) transceiver unit (SE2), a second signal (sigTX2) is generated and transmitted via the path (SP), in particular emitted. The radiation of the signals takes place here as possible at the same time but at least matched in time so that the two waveforms

preferably at least half of the airtime overlap. The signal sources may be completely or partially independent.

As usual in telecommunications, the transmitted signals used (sigTXl, sigTX2) can be represented as a decomposition into an equivalent baseband signal (bbTXl) and a carrier signal.

Since the system according to the invention is preferably to be used for distance measurement or for imaging, signals with so-called good correlation properties are preferably used as baseband signals. Signals with good correlation properties are, for example, broadband pulses, noise signals, pseudo-random pulse trains (PN codes) such as M-sequences, Gold codes or Barker codes, Kasami sequences, Huffman sequences, chirps, linear frequency modulated signals (FMCW), chirp or FMCW sequences, etc. Such waveforms have long been widely known in radar technology and communication technology (especially in the area of CDMA).

The transmission signal (sigTXl) of the transceiver unit (SEI) can be represented as follows:

The time offset TOI defines the transmission time of the signal sigTXl;

the phase term comprises a constant

Phase offset and the phase noise of the carrier signal.

The angular frequency characterizes the frequency of the carrier signal of sigTXl.

In the same way, the transmission signal (sigTX2) of the transceiver unit (SE2) can be formed. The following applies:

The transmitted signals (sigTXl and sigTX2) are sent directly to the other transceiver stations and are then received and processed further as receive signals sigRX12 and sigRX21.

The received signal, which is received at the second (non-coherent) transceiver unit (SE2), corresponds to the transmission signal (sigTXl), but this is changed in amplitude and delayed by the delay ^Tl1 . To simplify the mathematical representation and without limiting the general disclosure, all signals are to be represented below as complex-valued signals. It thus applies:

If the transmission signal (sigTXl) is transmitted to a plurality of (a number of I) transmission paths of different lengths to the second transceiver unit (SE2), the reception signal can be transmitted as a linear superposition of

amplitude-weighted and time-delayed signals are represented as follows:

For the transmitted from the second transceiver unit (SE2) to the first transceiver unit (SEI) signal applies accordingly

The transceiver units (SEI, SE2) are designed to be

Include signal comparison units SigCompl, SigComp2, in which the respective received signal of a transceiver unit is charged with its transmission signal - i. in SEI the signal sigRX12 with the signal sigTXl and in SE2 the signal sigRX21 with the signal sigTX2. The signal comparison units SigCompl, SigComp2 are designed in the exemplary embodiment as a mixer mix. That Here in SEI the signal sigRX12 is mixed with the signal sigTXl and in SE2 the signal sigRX21 with the signal sigTX2. As such, it is well known that a mixing operation can be system-theoretically expressed as multiplication or downmixing for two complex sine signals as multiplication of one of the signals with the conjugate complex (* = sign of conjugation) of the other signal. It therefore applies:

Another advantageous way to form a comparison signal is that SEI does not mix signal sigRX12 with signal sigTXl but only with its carrier. So:

The following applies to the signals in SE2:

Or in the alternative embodiment:

It is now assumed that funds are provided in SE to ensure that the following conditions are met:

How these means can preferably be configured has already been explained above or will be explained below in an exemplary embodiment. Under these boundary conditions results:

Assuming a reciprocal transmission channel, the following also applies:

In the next step, data communication ensures that both comparison signals are transmitted to a common evaluation unit, where they are both available for evaluation. The common evaluation unit may be SEI, SE2 or another evaluation unit.

Now, in a further processing step, the phases of the two comparison signals are added. If only the carrier phases with the phase noise component are considered here, since unknown phase contributions are present only in this component, and the two carrier phase terms are added together, the result is:

Considering that the term because of the large

Propagation speed of electromagnetic waves is usually very small and that the significant phase noise components in an oscillator according to the known relationships of oscillator phase noise typically decrease sharply with increasing distance from the carrier and, respectively, have a pronounced low-pass behavior and indeed

a low-pass response with a cut-off frequency, which is usually much smaller than, follows:

The proposed processing, that in one of the comparison signals, the phase of the other comparison signal is added, thus leads to the fact that the disturbances are significantly reduced by phase noise. These Phase noise reduction leads to a better detectability of targets, to a larger measuring range and an improved measuring accuracy.

Depending on the selected mixer topology, whether z. For example, a balance or a Kehrlage mixer is used, it is possible that the phase terms shown above have different signs. Depending on the sign, the preferred combination of the phase terms is not necessarily an addition but possibly also a subtraction. What matters is that the linkage results in a reduction of the phase noise echo and the term-dependent phase term, i. one

Expression that includes the term is preserved. It is also general

It is known that in the case where the phase values are represented by complex numbers, the complex numbers are multiplied, divided or multiplied by the conjugate complex of the other number to form the sum or difference of the phases.

A possible preferred variant for reducing the phase noise components will be described below. In many cases, it is favorable that in the first and second (non-coherent) transceiver unit (SEI, SEI) similar baseband signals are generated, that is, the following applies:

In an at least approximately reciprocal radio channel, it can furthermore be assumed that the following applies:

Under these boundary conditions results:

As you can see, the two signals are identical except for their phase terms.

However, slightly different amplitudes of the signals sigC12 and sigC21 may occur despite a reciprocal radio channel due to different characteristics of the electronic components such as mixers or amplifiers, etc. If the amplitudes of the signals sigC12 and sigC21 are different, the signals in the preferred variant described here must first be normalized to the same amplitude.

Also, the process of forming the sigC12 and sigC21 signals may result in additional systematic phase offsets. If these phase offsets of the signals sigC12 and sigC21 are different, these phase offsets must first be compensated in the preferred variant described here.

For a given time t, the signals sigC12 and sigC21 can be interpreted as complex pointers. By a complex addition of the pointers, the vector components of the phase terms with different signs cancel each other out in the same way as described above in the addition of the phase terms. Consequently, as a possible preferred variant for reducing the phase noise components, it is proposed to add the complex signals sigC12 and sigC21, ie to form a signal as follows:

The sigCC signal then has significantly less phase noise than the sigC12 and sigC21 signals, respectively, and the sigCC signal is then further used for the purpose of range finding, angle measurement or imaging.

However, it is important that before the addition of the signals, the previously described systematic deviations of amplitude and phases, which cause different carrier frequencies and transmission times, have been compensated. Of course, not all the values of sigC12 and sigC21 and not necessarily the signals sigC12 and sigC21 itself must be added. However, at least one complex value should be used from a first of the two comparison signals or from a signal derived from this first comparison signal, at least one complex value of the second of the two comparison signals or a value of a signal from this second one

Comparative signal has been derived, and thus to form at least one value of a signal (sigCC), wherein the adaptation is such that by a mathematical operation the vectorial sum or the difference of at least two sigC12 and sigC21 derived complex values is formed or the sum or the difference of the phases of these complex values is formed.

It should be noted here that the proposed mixing operations represent only one possible embodiment and that the compensation of

Phase noise components could also be realized by alternative methods. For example, all high frequency signals could be digitized before mixing, i. H. Scanned with an analog-to-digital converter, and all other operations could be done digitally or, for example, in a processor or FPGA (Field Programmable Gate Array).

In principle, the transmitted signals sigTXl and SigTX2 FMCW can be modulated. Preferably (before the mathematical operation) the

Spectra of the comparison signals are normalized to the highest value.

In the following, a special embodiment of the method II with FMCW signals and a plurality of successive N ramps will be described. The SE send several N signals with linearly increasing or decreasing frequency, hereinafter referred to as frequency ramps. From the received signals, the comparison signals are then generated in the SE and buffered for further processing. By way of example, increasing and decreasing ramps are used, since this is an accurate sign determination of the

Relative speed succeeds. First, individual spectrograms of the sigC12 and sigC21 beat signals are generated for each receive channel for each ramp. These spectrograms are juxtaposed in amplitude representation without phase information for all N consecutive ramps. This is shown in Fig. 4 for the rising ramps, in which two maxima appear, since no IQ mixture

was carried out, but a real-valued scanning signal is present. at

For use in primary radars, the at least one reflector in the detection area must be identified in advance for this step and displayed as described above.

Now, the frequency band in which the beat signal is expected to be generously cut out (ensured by a rough presync). Thereafter, the spectrogram of the first N / 2 ramps is correlated with that of the second N / 2 ramps along the frequency axis (step 1). The maximum found here represents the relative time drift of the two SEs (in this case, a linear function can be assumed). Upon receipt of the signals via one or more reflections, the identification of the targets via the opposing drift on both sides can also take place by way of example.

Alternatively, a determination of the frequency offset set in particular

Primary radars also take place via a common bus system by the systems exchange their measurement signals or further synchronization signals via the cables of a bus system. The bus system is in particular a CAN, FlexRay, Most, Gigabyte Ethernet system, USB, Firewire or TTP system.

Thereafter, all the ramps in the spectrogram are corrected for this drift by, for example, using a complex offset offset correction signal in the clock adaptation unit or

Comparison signal modification 2 multiplied. The resulting spectrograms of the different ramps are added (incoherently) and as a result of the

Overlay the maximum is searched, which corresponds to the time offset (offset error). For primary radar, the selection of peaks can be done using the identification of the peaks belonging to each other in the previous step. Alternatively, a determination of the time offset can also take place via a common bus system, in particular by transmitting either the measurement data or suitable correlation sequences.

The relative time offset and relative time drift (= actual frequency offset) parameters determined in this way are averaged over the complete sequence of N ramps. This result contains a large part of

Clock deviation. In addition, it is now known for each ramp and each station at which point in the spectrogram the energy of the incident signal is to be expected.

The originally recorded local mixed signals sigC12 and sigC21 are now first shifted by integer values Tint (representation of the time offset between the two stations as ΔΤ = | T01-T02 i = Tint + Tfrac) in order to obtain a uniform time base. Due to the common exact time base the phase noise is more correlated. The remaining, small time error Tfrac can now be compensated, for example by using a fractional delay filter. The shifted signals are now different

Fixed slope steepness, which arises due to the frequency offset Δ ω = ωΐ- ω2 of the two local oscillators by folding with a normalized complex correction signal or spectrally multiplied, which the

Frequency response maps in the opposite direction.

In these sharpened mixed signals, a peak is now searched in each case for an FFT of the beat signal for the channel impulse response. In the case of secondary radar, it is preferable to take the strongest peak or, alternatively, the first peak; in the case of primary radar, one must choose a peak that is equally contained on both sides. For each ramp at both stations, this results in a maximum at the estimated distance with the associated phase angle. These values agree in principle for the measurement on the way in and return in a reciprocal channel. The remaining deviations are due to remaining frequency and phase differences between the two signal sources 1 of the SE, for example, the oscillators, which is based on phase noise as a cause. The exact frequency difference can now be determined absolutely and thus corrected (the phase difference can be up to 180 ° ambiguity (at IQ

Mixers 360 °) can be determined). This ambiguity is resolved by ramping the ramp to +/- 90 ° from ramp to ramp, also known as unwrapping. After this precise correction of the

remaining phase error, the synthetic mixed signals of both stations now hardly differ.

After this preprocessing, the characteristic, systematic errors of the radar system were completely corrected, which is why the

Phase shift of the two beat signals deviates only by a small amount. At this point, on the one hand, a precise synchronization of the time and frequency base is achieved and on the other hand, the phase noise can be considered as an additive contribution and corrected by linear combination. This is done for example by means of 2D Fourier transformation of all N ramps on both SEs, whereupon the, in the amplitude normalized beat signals are added. Taking into account the system parameters (sampling rate,

Ramp steepness, carrier frequency,...), The maximum of the result of this linear combination represents the estimated value for distance and speed.

5 shows by way of example a conventional arrangement for a radar system with transceivers SEI, SE2, which each have at least two transmitting and receiving antennas, as well as with an HF generator for the RF signal and a distribution device for a distribution of the HF Signal to the transceivers SEI, SE2 and a clock for a

System clock.

Fig. 6 shows an arrangement of a radar system according to the invention with transceivers SEI, SE2, each having at least two transmitting and receiving antennas and an RF generator, and with a

(common) clock for a system clock.

FIG. 7 shows a phase noise diagram for IF signals derived from the

Downmixing signals originate from different signal generators, as with a radar system of FIG. 6 and the use of a suitable phase locked loop, but without a method for the subsequent generation of coherence.

Fig. 8 shows a signal propagation for the radar system according to the invention. The signals received by each receive path include their own environmental reflected signals and the environmental reflected signals of a second transmit path.

The received signals are sent to the local radio frequency signal

downmixed or correlated. This produces a low-frequency signal S eat, which has both components from the direct reflection path (own transmission signal) and from the indirect reflection path (external transmission signal). Subsequently, the signals are separated via the frequency difference or another modulation. The signals of the own reflection path are then processed as normal radar signals, the signals of the indirect path are processed further as follows:

Optionally, the indirect signals from both receive paths are corrected for any frequency offset. In addition to the frequency offset set, possibly to

Distinction / coding of the two signals was introduced

Frequency offset also be disturbing system frequency offsets. The

Correction of the latter, however, is usually unnecessary because of the common clock source. Timing offsets, for example by (slightly) different timings of the H F generators (frequency generators) are also corrected, for example in the postprocessing by (for example) the application of DE 101 57 931. Subsequently, two spectra (spectrum 1 and spectrum 2) of formed two signals and preferably normalized with respect to their amplitudes. By a mathematical operation, the sum or difference of the complex spectra, or of signals derived from the spectra, can be formed, or the sum or the difference of phase values of the aforementioned signals is formed.

A preferred variant of the evaluation can proceed as follows: One of the two calculated spectra (spectrum 1) is preferably converted into a complex conjugate spectrum (spectrum IC). This spectrum (spectrum IC) and the nonconjugated complex converted spectrum (spectrum 2) are added or subtracted in a mathematical operation or multiplied or divided. The resulting spectrum can then be processed like a normal radar spectrum.

It is advantageous that due to the mathematical combination of the two signals (spectrum 1 and spectrum 2) the additional noise caused by the

Using the separate RF signal sources was generated, can be suppressed very effectively.

Particularly preferably, the transmit and receive paths are arranged as sparse arrays. As a result, the secondary maximum and total aperture can be optimized so that accuracy and target separation are significantly improved. Also preferred is the use of chips that already have integrated antennas, either in the chip directly or in a corresponding package.

Hereinafter, aspects and embodiments of the method I and the configuration I will be described. The reference numbers refer to the figures from DE 10 2014 104 273 AI. The transceiver units can be part of the (possibly at least partially coherent) transceiver devices or form them:

1st aspect: Method in a radar system, in which

a first signal (sigTX2) is generated in a further, in particular second (non-coherent) transceiver unit (SE2) and is transmitted, in particular transmitted, via the path (SP),

in the first transceiver unit (SEI) a comparison signal (sigC12) is formed from the first signal (sigTXl) thereof and from such a first signal (sigTX2) received by the further transceiver unit (SE2) via the path (SP), and

- In the further transceiver unit (SE2), a further comparison signal (sigC21) from the first signal (sigTX2) and from such from the first transceiver unit (SEI) via the path (SP) received first signal (sigTXl) is formed . - Wherein the further comparison signal (sigC21) from the further transceiver unit (SE2) to the first transceiver unit (SEI) transmitted, in particular is communicated.

Second aspect: Method according to the first aspect, in which a comparison comparison signal (sigC21; sigC12) is formed from this comparison signal (sigC21) and the further comparison signal (sigC21).

3. Aspect A method according to the second aspect, in which the comparison comparison signal (sigC21; sigC12), by the two comparison signals (sigC12, sigC21) being processed together - in particular conjugated complex multiplied - corresponds to a comparison signal generated with a coherent radar system.

4. Aspect: A method according to any preceding aspect, wherein at least one of the comparison signal (sigC12), the further comparison signal (sigC21) or the comparison comparison signal (sigC21; sigC12) is formed by at least one of mixing and correlation.

5. Aspect: Method according to a preceding aspect, in which at least one such further comparison signal (sigC21; sigC12) is transmitted between the transceiver units (SE2; SEI) as at least one of data, a data-containing signal or a data reconstructible signal ,

Sixth aspect: A method according to any preceding aspect, wherein at least one of the first signals (sigTXl, sigTX2) is transmitted as a transmission signal via the air interface path (SP).

7. Aspect: Method according to a preceding aspect, in which points in time for the transmission of the first signals (sigTX1, sigTX2) are coordinated in such a way that the first signals (sigTX1, sigTX2) at least partially overlap in time.

8. Aspect: Method according to a preceding aspect, wherein from at least one comparison comparison signal (sigC21; sigC12) a signal propagation time (τ12), such a first signal (sigTXl, sigTX2) for the path between the transceiver units (SEI, SE2) is determined by at least one from a phase or a phase value (φ12, φ13, ..., φΙΝ, φ22, φ23, φ24, ... φ2Ν, ..., φΝ-1Ν) of a frequency, an amplitude curve or a phase curve of the comparison Comparison signal (sigCC12) is analyzed.

9. Aspect: A method according to any preceding aspect, wherein at least one of the first signals (sigTXl, sigTX2) is generated and transmitted as an FMCW or OFDM modulated signal.

10. Aspect: A method according to any preceding aspect, wherein at least one of the first signals (sigTXl, sigTX2) is generated and transmitted as a multi-ramp signal.

11. Aspect: Method according to a preceding aspect, in which

a plurality of comparison comparison signals (sigCC12) which are measured in succession with at least two transceiver units (SEI, SE2), of which at least one of the transceiver units (SEI, SE2) moves, and

with a synthetic aperture method at least one of one

Distance, position, velocity or the presence of one of the transceiver units (SE2, SEI) or the presence of such transceiver units (SE2, SEI), or at least one of a distance, position, velocity relative to an object ( 0) or the presence of an object (0) is determined.

12th aspect: radar system in which

at least a first (non-coherent) transceiver unit (SEI)

is designed to generate a first signal (sigTXl) and to transmit it via a path (SP), in particular to emit it,

at least one further, in particular second (non-coherent) transceiver unit (SE2) is designed to generate a first signal (sigTX2) and to transmit it via the path (SP), in particular to emit it,

- The first transceiver unit (SEI) is formed, a comparison signal (sigC12) from the first signal (sigTXl) and from such from the further transceiver unit (SE2) via the path (SP) received first signal (sigTX2) form,

- The further transceiver unit (SE2) is formed, another

Comparison signal (sigC21) from the first signal (sigTX2) and from one such first signal (sigTXl) received from the first transceiver unit (SEI) via the path (SP), and

- The further comparison signal (sigC21) from the further transceiver unit (SE2) to the first transceiver unit (SEI) is transmitted, in particular is communicated.

13. Aspect: Radar system according to aspect 12, in which a comparison comparison signal (sigCC21; sigCC12) is formed from this comparison signal (sigC21) and the further comparison signal (sigC21).

14. Aspect: A radar system according to aspect 12 or 13 comprising three or more spatially-spaced transceivers (SEI, SE2, SE3, SE-N), comprising two or more comparative comparison signals (sigCC12, sigCC12, sigCC13, sigCC22, sigCC32 ) measured with more than two pairs of each two of the spaced-apart ones of the transceiver units (SEI, SE2, SE-N, SE2), a distance, a position, a velocity or the like

Presence of one of the transceiver units (SE2, SEI) or the

Presence of such a transceiver unit (SE2, SEI) or at least one of a distance, a position, a speed relative to an object (0) or the presence of an object (0) is determined.

15. Aspect: Radar system according to one of aspects 12 to 14, in which the first transceiver unit (SEI) and at least one such further transceiver unit (SE2) and / or an evaluation unit (P) are designed to carry out a method according to one previous claims.

16. Aspect: Device of a radar system, in particular for carrying out a method according to one of the aspects 1 to 11 and / or in one

Radar system according to one of the aspects 12 to 15, wherein the device

- Is formed as a first (non-coherent) transceiver unit (SEI), in particular first (non-coherent) transceiver unit (SEI) and

a signal generator and at least one antenna (TAI, RAI), which are designed to generate a first signal (sigTX1) and to transmit them via a path (SP), in particular to emit them,

an arrangement which is designed to generate a comparison signal (sigC12) from the first signal (sigTXl) and from a signal from another transmitter Receiving unit (SE2) via the path (SP) received first signal (sigTX2) to form

- and at least one of

an interface (CommTX), which is designed to transmit the comparison signal (sigC12) to the further transceiver unit (SE2),

in particular to communicate or

- An interface (CommRX), which is designed to receive such a further from the further transceiver unit (SE2) generated further comparison signal (sigC21) by transmitting, in particular communicating, in the first transceiver unit (SEI).

17. Aspect: Device according to aspect 16 with a further comparison unit (sigCompl2), which forms a comparison comparison signal (sigCC12) from the comparison signal (sigC21) formed in the same transceiver unit (SEI) and to this transceiver unit (SEI ) transmitted comparison signal (sigC21).

18. Aspect: Device according to aspect 16 or 17, in which the at least one interface (CommTX, CommRX) is a data interface.

19. Aspect: Device according to one of aspects 16 to 18, wherein between the arrangement which outputs the comparison signal (sigC12) and the other

Comparing unit (sigCompl2) forming the comparison comparison signal (sigCC12), a filter (FLT) is arranged, wherein the filter (FLT) to the

Comparing unit (sigCompl2) applies the comparison signal (sigC12), wherein the filter (FLT) another in the filter (FLT) upstream arrangement formed comparison signal (sigCl l) does not apply and the reference signal formed in the upstream arrangement (sigCl l) suppressed or at one

Connection provides.

20. Aspect: Device according to one of the aspects 16 to 19, comprising a plurality of mutually spatially spaced receiving antennas (RA1,1, RA1, N; RA2,1,

RA2, N), to each of which an arrangement is assigned, which is designed to generate in each case one comparison signal (sigC21, l, sigC21,2, sigC21,3) from the first signal (sigTX2) and from one such from another such transmission signal. Receiving unit (SE2) via the path (SP) received first signal (sigTXl) to form. Hereinafter, aspects and embodiments of the method II and the configuration II will be described. The reference numbers refer to FIGS. 1 to 4 of the present application. The transceiver units can be part of (or at least partially coherent) transceivers, or can form them:

1. Aspect: A method for reducing phase noise interference in a radar system, in which

in a further, in particular second (non-coherent) transceiver unit (SE2), a first signal (sigTX2) is generated and transmitted, in particular transmitted, over the path (SP),

the first signals (sigTXl and sigTX2) are received in the respective other transceiver unit directly or indirectly, where they are further processed as received signals (sigRX12 and sigRX21),

in the first transceiver unit (SEI), a comparison signal (sigC12) is formed from its first signal (sigTXl) and from such a first signal (sigRTX2) received by the further transceiver unit (SE2) via the path (SP), and

in the further transceiver unit (SE2), a further comparison signal (sigC21) is formed from its first signal (sigTX2) and from such a first signal (sigTXl) received by the first transceiver unit (SEI) via the path (SP),

wherein the further comparison signal (sigC21) is transmitted, in particular communicated, from the further transceiver unit (SE2) to the first transceiver unit (SEI),

wherein in a first step deviations of the comparison signals (sigC21 and sigC12) caused by systematic deviations in the transceiver units (SE2, SEI) are compensated,

wherein, in a second step, at least one complex value from a first of the two comparison signals or from a signal resulting from the first Derived signal is used to adapt at least one complex value of the second of the two comparison signals or a value of a signal derived from this second comparison signal, and thus to form a matched signal (sigCC),

the adaptation being such that the vectorial sum or the difference of the complex values is formed by a mathematical operation or the sum or the difference of the phases of the complex values is formed.

2. Aspect: Method according to aspect 1, wherein the transmitted signals (sigTXl and SigTX2) are FMCW modulated.

3. Aspect: Method according to aspect 1 or 2, wherein a clock rate adjustment, in particular of signal sources of the first signals (sigTXl and sigTX2), via a bus system, preferably a communication bus, takes place and / or

wherein a clock rate adjustment, in particular of clock rates of signal sources of the first signals (sigTXl and sigTX2), via radio waves and / or via a

Cable connection, especially when operating as a primary radar occurs.

4. Aspect: Method according to one of the preceding aspects, wherein a synchronization of the (non-coherent) transceiver units (SEI, SE2), in particular a pre-synchronization by a determination of a frequency drift over a plurality of ramps takes place successively, in particular when using a secondary radar ,

5. Aspect: Method according to one of the preceding aspects, wherein an offset, in particular a time offset and / or a frequency offset, via a

Bus system is determined, preferably when operating as a primary radar.

6. Aspect: Method according to one of the preceding aspects, wherein an offset, in particular a / the time offset and / or the / the frequency offset, via an evaluation of a position of, in particular corrected, maxima of the spectra of the comparison signals (sigC12 and sigC21) , is determined. 7. Aspect: Method according to one of the preceding aspects, wherein the first and / or the further (non-coherent) transmitting and receiving unit has at least one evaluation device for carrying out the individual method steps, in particular calculations and evaluations, wherein the respective evaluation device

if necessary, a physically independent evaluation device which is connected to the respective transmitting and receiving unit or the other components of the respective transmitting and receiving unit or

possibly in the first and / or the further (non-coherent) transmission and

Receiving unit, for example, in a common housing and / or as a unit, is integrated.

8. Aspect: Method according to one of the preceding aspects, wherein the comparison signals (sigC12 and sigC21) are transmitted to a, in particular common, evaluation unit and there for evaluation both exist, wherein the common evaluation unit, optionally, the first (non-coherent) Send Receiver unit (SEI) or, optionally, the second (non-coherent) transceiver unit (SE2) or, optionally, another, in particular separate, evaluation unit.

9th aspect: Method according to one of the preceding aspects, wherein the first signals (TX1 and TX2) are transmitted overlapping at least in time, the further first signal (TX2) of the further (non-coherent) transceiver unit (SE2) preferably at least during half of the

Signal duration of the first signal (TX1) of the first (non-coherent) transceiver unit (SE2), more preferably at least approximately simultaneously, is sent.

10. Aspect: Method according to one of the preceding aspects, wherein before the mathematical operation the spectra of the comparison signals are normalized to the highest value. 11. Aspect: System for reducing phase noise interference in a radar system with units for carrying out the method according to one of the preceding claims, comprising in particular: a first (non-coherent) transceiver unit (SEI) for generating a first signal (sigTXl) and for transmitting, in particular radiating, the first signal (sigTXl) via a path (SP), a further, in particular second, (non-coherent) transceiver unit (SE2) for generating a first signal (sigTX2) and for transmitting (in particular Radiating) the first signal (sigTX2) via the path (SP), wherein the (non-coherent) transceiver units (SEI and SE2) are formed, the first signals (sigTXl and sigTX2) in the respective other transceiver on direct or indirectly to receive and process there as received signals (sigRX12 and sigRX21), wherein the first transceiver unit (SEI) is formed, a

Comparative signal (sigC12) from the first signal (sigTXl) and from such from the further transceiver unit (SE2) via the path (SP) received first signal (sigRTX2) to form and wherein the further transceiver unit (SE2) is formed to form a further comparison signal (sigC21) from its first signal (sigTX2) and from such a first signal (sigTXl) received by the first transceiver unit (SEI) via the path (SP). wherein a transmission unit is provided to the other

Comparative signal (sigC21) from the other transceiver unit (SE2) to the first transceiver unit (SEI) to transfer, in particular to

communicate, wherein at least one evaluation unit is provided, which is designed to compensate for deviations of the comparison signals (sigC21 and sigC12) caused by systematic deviations in the transceiver units (SE2, SEI) in a first step, and in a second step at least one complex value from a first of the two

Compare signals or from a signal derived from this first comparison signal to use to adapt at least one complex value of the second of the two comparison signals or a value of a signal derived from this second comparison signal, and thus a matched signal (sigCC) the adaptation being such that the vectorial sum or the difference of the complex values is formed by a mathematical operation or the sum or the difference of the phases of the complex values is formed.

12. Aspect: System according to aspect 11, wherein a bus system, in particular a communication bus, is provided for a clock rate adjustment, in particular of signal sources of the first signals (sigTX1 and sigTX2),

and / or wherein a bus system is provided for determining an offset, in particular a time offset and / or a frequency offset.

13. Aspect: System according to one of the aspects 11 or 12, wherein a common transmitting and receiving antenna in the first and / or the further (non-coherent) transceiver unit (SEI and / or SE2) is provided and / or wherein a transmission mixer in the path (SP) is provided.

14. Aspect: Use of the method according to one of the aspects 1 to 10 for a system with at least one common transmitting and receiving antenna in the first and / or second (non-coherent) transceiver unit (SEI and / or SE2).

Aspect 15: Use of the system according to any one of aspects 11 to 13 for reducing phase noise interference in a radar system. It should be noted at this point that all parts or functions described above, taken alone and in any combination, in particular the details shown in the drawings, are claimed as essential to the invention. Variations thereof are familiar to the person skilled in the art.

Claims

claims

1. Radar system comprising:

at least one first (SEI) and one second (SE2) transceiver device each having at least one transmitting and at least one receiving antenna and an HF generator and a common clock generator for the RF generators of the transceivers,

wherein at least one evaluation device is provided which

is configured to process transmit and receive signals of the transceivers (SEI, SE2) to modified measurement signals with increased coherence.

2. System according to claim 1, wherein the first transceiver

(SEI), preferably with its HF generator, and / or the second transceiver (SE2), preferably with its RF generator, on a circuit board, in particular together with the common clock, is arranged / are.

3. System according to claim 1 or 2, wherein the H F generators are arranged in the vicinity of the transmitting and receiving antennas.

4. System according to any one of the preceding claims, wherein the RF signals of the individual RF generators are at least partially coherent with each other, to which preferably a phase locked loop (PLL) is provided.

5. System according to one of the preceding claims, wherein

- In the first transceiver (SEI), a first signal

(sigTXl) generated and transmitted over a path (SP), in particular, is broadcast,

in the second transceiver device (SE2), a further first signal (sigTX2) is generated and sent over the path (SP), in particular emitted,

- In the evaluation, in particular in the first transceiver (SEI), a first comparison signal (sigC12) from the first signal (sigTXl) of the first transceiver and from such from the second transceiver (SE2), over the path (SP), the first signal (sigTX2) is formed and

- In the evaluation, in particular in the second transceiver (SE2) another comparison signal (sigC21) from the first signal of the second transceiver (sigTX2) and from such from the first transceiver (SEI), over the path (SP) received, first signal (sigTXl) is formed,

- wherein the further comparison signal (sigC21) is preferably transmitted from the second transceiver device (SE2) to the first transceiver device (SEI), in particular, is communicated.

6. System according to one of the preceding claims, wherein the system, in particular the evaluation device for forming a comparison comparison signal (sigCC21; sigCC12) from the first comparison signal (sigC21) and the further comparison signal (sigC21) is configured.

7. System according to one of the preceding claims, wherein the system, in particular the evaluation device is configured to in a first Step deviations of the comparison signals (sigC21 and sigC12), which are caused by systematic deviations in the transceivers (SE2, SEI) to compensate and in a second step at least one complex value from a first of the two comparison signals or from a signal that from this first one

Comparative signal is derived to be used to adapt at least a complex value of the second of the two comparison signals or a value of a signal derived from this second comparison signal, and thus to form a matched signal (sigCC), wherein the adaptation is such that by a mathematical operation the vectorial sum or the difference of the complex values is formed or the sum or the difference of the phases of the complex values is formed.

8. System according to any one of the preceding claims, wherein the comparison comparison signal (sigC21; sigC12) by the two comparison signals (sigC12, sigC21) processed together - are multiplied complex, in particular conjugated complex - corresponds to a comparison signal generated with a coherent radar system.

9. System according to one of the preceding claims, wherein the first (SEI) and / or second (SE2) transceiver means two or more transmitting antennas and / or two or more receiving antennas

has / have.

10. System according to any one of the preceding claims, wherein the transceiver means (SEI, SE2) are arranged understaffed.

11. System according to one of the preceding claims, wherein the system, in particular a control device of the system is configured so that the transmission antenna (s) of the first (SEI) and the transmission antenna (s) of the second (SE2) transceiver simultaneously or in time transmit overlapping and / or such that transmit signals of the

Transmission antenna (s) of the first (SEI) and the transmission antenna (s) of the second (SE2) transceiver differ from each other,

in particular have a frequency offset against each other and / or itself differ from each other by a pulse, amplitude and / or phase modulation.

12. System according to any one of the preceding claims, wherein the system, in particular one / the control device of the system is configured so that received signals and the transmitted signal are mixed or correlated, preferably followed by a separation of the received signals due to a distinguishing feature, in particular one Frequency offsets against each other and / or a different pulse, amplitude and / or phase modulation of the transmission signals, to which the received signals are due, takes place.

13. System according to any one of the preceding claims, wherein the system, in particular one / the control device of the system is configured, preferably in particular with respect to their amplitude normalized, possibly complex, spectra of indirect, reflected, received by the transceiver signals to form, where

preferably by a mathematical operation, a sum or a difference of the (complex) spectra, or of signals derived from the spectra, or a sum or a difference of phase values of the indirect reflected signals received by the transceivers becomes.

14. A method for operating a radar system, in particular according to one of the preceding claims, wherein the radar system at least a first (SEI) and a second (SE2) transceiver each with at least one transmitting and at least one receiving antenna and a RF generator and a common clock generator for the RF generators of the transceivers,

wherein transmit and receive signals of the transceivers (SEI, SE2) to modified measurement signals with increased coherence

are processed.

15. The method of claim 14, wherein

- In the first transceiver (SEI), a first signal

(sigTXl) generated and transmitted over a path (SP), in particular, is broadcast, in the second transceiver device (SE2), a further first signal (sigTX2) is generated and sent over the path (SP), in particular emitted,

a first comparison signal (sigC12) is formed from the first signal (sigTXl) of the first transceiver and from such a first signal (sigTX2) received by the second transceiver (SE2) via the path (SP), and

- Another comparison signal (sigC21) from the first signal of

second transceiver (sigTX2) and from such from the first transceiver (SEI), via the path (SP) received, the first signal (sigTXl) is formed,

- wherein the further comparison signal (sigC21) preferably from the

second transmitting-receiving device (SE2) to the first transceiver (SEI) transmitted, in particular is communicated and / or

wherein preferably a comparison comparison signal (sigCC21; sigCC12) is formed from the first comparison signal (sigC21) and the further comparison signal (sigC21) and / or wherein in a first step

Deviations of the comparison signals (sigC21 and sigC12), which are caused by systematic deviations in the transceivers (SE2, SEI), are compensated and in a second step at least one complex value from a first of the two

Comparison signals or from a signal coming from this first

Comparative signal is derived, is used to adapt at least one complex value of the second of the two comparison signals or a value of a signal derived from this second comparison signal, and thus to form a matched signal (sigCC), wherein the adaptation is such that by a mathematical operation the vectorial sum or the difference of the complex values is formed or the sum or the difference of the phases of the complex values is formed.