DE102012222334B4 - Method for determining the relative distance and the relative movement of several road users - Google Patents

Abstract

Method for determining the relative distance and/or the relative movement between at least two road users (T1, T2), in particular between at least two vehicles, based on the reception of acoustic signals (51) resulting from initialization emissions in the form of acoustic signals (11). come from a first road user (T1), reaction emissions are triggered by a second road user (T2) in the form of acoustic signals (71), which are received and evaluated by the first road user (T1), the reaction emissions of the second Road user (T2) after the expiration of at least one delay time (TD) known to the road users (T1, T2), which is set so long that acoustic signals received by the first road user (T1), which consist of passive reflections of the initialization emissions of the first Road user (T1) originate from surrounding objects, have no influence on an evaluation carried out by the first road user (T1) of the reaction emissions (71) of the second road user (T2) received by means of at least one receiver (30), characterized in that based on the first road user (T1) received acoustic signals (31) of the reaction emissions of the second road user (T2) reaction emissions of acoustic signals from the first road user (T1) are triggered after the expiration of at least one delay time known to the road users (T1, T2) and of such a length that the acoustic signals received by the second road user (T2), which come from passive reflections of the acoustic signals of the reaction emissions of the first road user (T1) on surrounding objects, have no influence on one used by the second road user (T2) to determine the relative distance and / or the relative movement between the two road users (T1, T2) carried out evaluation of the acoustic signals of the reaction emissions of the first road user (T1) received by the second road user (T1, T2) by means of at least one receiver (50).

Description

Field of invention

The present invention relates to a method for determining the relative distance and / or the relative movement of at least two road users, in particular at least two vehicles, in which reaction emissions of acoustic signals from one of the acoustic signals are based on the initialization emissions of acoustic signals generated by a first road user of the two road users of the second road user receiving initialization emissions are triggered and are received and evaluated by the first road user. The invention further relates to a corresponding device for determining the relative distance and/or the relative movement between at least two road users, in particular between at least two vehicles. The invention also relates to a vehicle assistance system with a corresponding device.

State of the art

Pulse-based measuring systems that work in the ultrasonic range are currently used to acoustically detect the surroundings of vehicles. Typically, acoustic pulses at around 50 kHz are sent out every 10 ms to 300 ms via an electro-acoustic converter. The distance to the object in space is deduced from the pulse transit time to the transmitting and non-transmitting transducers.

In the applicant's earlier patent applications it was suggested that the selection of the acoustic medium should not be limited to ultrasound around 50 kHz. The decision 30 years ago in favor of the ultrasonic range was, on the one hand, based on the fact that in this frequency range the noise power decreases sufficiently in proportion to the reciprocal of the signal frequency, and on the other hand, the attenuation caused by the medium was still within manageable limits, and that at that time the first affordable electronic ones Components for this frequency range emerged.

Technology has evolved since then: cars are becoming quieter, electromagnetic compatibility (EMC) problems are becoming more manageable, and with signal processing now available in every MP3 player (MP3 player), more efficient filtering is possible at an affordable price.

In particular, with the introduction of electric vehicles, it is now necessary for these vehicles to make themselves acoustically noticeable through synthesized sound in order to at least warn passers-by or other road users. In the applicant's older patent applications, it was therefore already proposed to combine the entire frequency spectrum of the ultrasonic range with that of the human hearing range as a whole for the acoustic monitoring of a vehicle environment by evaluating the sound emitted by the vehicle itself, in particular by evaluating the synthesized sound emitted by the vehicle and / or of the sound generated by the vehicle itself for functional reasons, for locating signal transmitters or sound sources and thus for increasing traffic safety.

The document DE 30 24 791 C2 describes a device for monitoring the position of a work ship, where it is described as prior art that in a known solution on the underside of a drilling ship four microphones are attached at a distance from one another, while at a certain point near the borehole on the bottom of the water there is an acoustic transponder is arranged. This acoustic transponder is controlled by an acoustic transmitter on the underside of the ship and is therefore caused to emit acoustic signals. The acoustic signals emanating from a single point on the bottom of the water are recorded by three microphones with a larger or smaller phase shift depending on the position of the ship, which is processed in a computer, whereby the position of the ship can be corrected.

In the documents DE 23 35 613 A1 and DE 23 35 613 B2 A method for measuring distances, changes in distance and/or changes in speed of objects moving relative to one another, in particular for vehicles of all kinds, is described. Here, the acoustic signal emitted by the transmitter of a first object is received by the receiver of a second object, its frequency position is changed, and then immediately and actively reflected in order to be received by the receiver of the first object. The use of acoustic beams, in particular ultrasound, is mentioned as particularly suitable for the application of the measuring method on land and water vehicles. The distance between two vehicles is determined based on a transit time evaluation and the relative speed is determined from the Doppler shift. It is also stated that information can be modulated onto the signals.

In summary, it is known from the prior art to generate initialization emissions of acoustic signals from a first object of the two objects in order to determine the relative distance and / or the relative movement between at least two objects, which are received by a second object of the two objects and by means of a evaluation can be recognized as such. Furthermore, it is known from the prior art to generate reaction emissions of acoustic signals from the second object as a direct response to the received acoustic signals of the initialization emissions. The acoustic signals of the reaction emissions from the second object are received by the first object and evaluated to determine the relative distance and/or the relative movement between the two objects.

The disadvantage of implementing classic transponder methods in the sound or ultrasonic range is the low propagation speed of sound or ultrasound compared to transmission using electromagnetic waves. Classic acoustic transponders already begin emitting reaction emissions, while the initialization transmissions have not yet fully arrived. In addition to this temporal collision that occurs with such a transponder method, temporal collisions with echoes from passively reflecting objects also take place. The disadvantage here is the high implementation effort that is required when evaluating the received acoustic signals of the reaction emissions because of the received echo signals arriving at the same time or quasi-simultaneously, which come from passive reflections of the acoustic signals of the initialization emissions on surrounding objects. In normal road traffic, several road users use the same transmission medium. The effort required increases if several road users are to generate reaction messages to the same initialization message in the same medium. It is also disadvantageous if every electro-acoustic converter that is located on a road user reacts in the same way to the arrival of each initialization transmission.

Another disadvantage of classic transponder methods is that they are only suitable for a few forms of initialization signals. Interoperability between different types of acoustic transponder methods is often not possible and the use of new technology, such as more complex modulation methods, is not supported by existing transponders. However, different types of road users come together on public roads, and their equipment often differs greatly.

The document US 5,062,088A discloses a device for measuring distances between two objects.

The font DE 699 08 628 T2 discloses a proximity measuring device for installation in road vehicles to measure their distance from one another.

The document US 2011/0025494 A1 discloses an automatic sensory system and method for position determination.

Disclosure of the invention

According to the invention, a method for determining the relative distance and / or the relative movement between at least two road users, in particular between at least two vehicles, is provided, in which the reception of acoustic signals that come from initialization emissions in the form of acoustic signals from one were sent out by the first road user, reaction emissions are triggered by a second road user in the form of acoustic signals, which are received and evaluated by the first road user. The reaction emissions of the second road user are carried out after the expiration of at least one delay time known to the road users, which is set so long that acoustic signals received by the first road user, which come from passive reflections of the initialization emissions of the first road user on surrounding objects, have no influence on one carried out by the first road user to evaluate the reaction emissions from the second road user received by at least one receiver.

Furthermore, according to the invention, a device for determining the relative distance and/or the relative movement between at least two road users, in particular between at least two vehicles, is provided, which is designed to detect the initialization emissions of acoustic signals generated by at least one road user of the two road users by means of at least one Receive the receiver and recognize it as such by means of an evaluation and generate reaction emissions of acoustic signals in response to the received initialization emissions from the at least one road user. Furthermore, the device is further designed to to generate the reaction emissions of acoustic signals with a predetermined signal duration after the expiration of at least one predetermined delay time known to the road users.

The subclaims show preferred developments of the invention.

In the method according to the invention, reaction emissions of acoustic signals from the first road user are triggered after the expiration of at least one delay time known to the road users, in particular based on the acoustic signals received from the first road user from the reaction emissions of the second road user. This delay time is set for such a long time that the acoustic signals received by the second road user, which come from passive reflections of the acoustic signals of the first road user's reaction emissions on surrounding objects, have no influence on one used by the second road user to determine the relative distance and / or the relative movement between the two road users is carried out by evaluating the acoustic signals of the reaction emissions from the first road user received by the second road user using at least one receiver.

In other words, such reaction emissions generated upon receipt of an initialization broadcast and optionally also those further reaction emissions generated in response to the receipt of reaction emissions from at least one road user who receives the acoustic signals from actively generated emissions (initialization emissions and/or reaction emissions) from at least one other road user and optionally receives and recognizes a sound source present in the acoustic environment, are sent out after the expiry of a firmly agreed delay time that is known to the relevant road users.

By using the firmly agreed delay time that is known at least to the road users involved, collisions can only occur between reaction emissions or further reaction emissions from such road users who are at the same distance from the road user generating the actively generated emissions of acoustic signals.

If there are several road users in traffic, the reaction emissions or the further reaction emissions of acoustic signals can be generated in response to the actively generated emissions from the road user or the sound source generating them after the expiry of a firmly agreed delay time that is known at least to the road users involved and in particular is different in each case become.

By using a firmly agreed delay time that is known at least to the road users involved and is different in each case, collisions of reaction emissions from those road users who are at the same distance from the road user generating the actively generated emissions of acoustic signals can also be easily avoided. In other words, the pseudo-random use of a different delay time from a set of a set of clearly different delay times known to all road users ensures that the collision probability of the reaction emissions of even those road users who are at the same distance in terms of transit time is statistically reduced.

By using a firmly agreed delay time that is known to at least the road users involved, the road user who initiated the actively generated emissions of acoustic signals can benefit from the transit time between the time at which their actively generated emissions were initiated and the time at which the acoustic signals were received In response to the received acoustic signals of the actively generated emissions, reaction emissions from the other road user draw conclusions about the distance between the two road users at the moment of signal exchange.

According to the invention, fixed delay times are used which are so long that all echoes, even from potentially distant passively reflecting objects in the environment, are already closer to the receiving road user. This means that collisions between the acoustic signals of the corresponding reaction emissions and echoes from passively reflecting surrounding objects are easily reduced to a minimum. The fact that no further evaluation of simultaneously or quasi-simultaneously received echoes from passively reflecting surrounding objects has to take place during an evaluation according to the invention of the received acoustic signals of the reaction emissions, reduces the reaction during the evaluation of the acoustic signals according to the invention tion emissions required to implement a corresponding evaluation unit is significant.

By using the delay times according to the invention, the loud-quiet problem (loud reaction emissions versus quiet echoes of passive reflections) is also defused. The corresponding evaluation units of the road users, which receive the acoustic signals of the initialization emissions or reaction emissions from other road users, can first be set to receive quiet echoes that come from passive reflections of the acoustic signals of these initialization emissions or reaction emissions. The same evaluation units can then, when no more echoes arrive, that is, after the delay times according to the invention have expired, respond to the reception of loud acoustic signals from the reaction emissions generated in response to the received acoustic signals of the initialization emissions or to the reception of loud acoustic signals from the Further reaction emissions generated in response to the received acoustic signals of the reaction emissions can be adjusted. This then increases the probability of detection of both quiet echoes and loud reaction emissions, which means that the previously mentioned loud-quiet problem can be significantly defused.

According to the invention, a method is thus provided for determining the position and/or movement of road users actively emitting acoustic signals and/or optionally also of passively reflecting objects in the vicinity of movement aids by means of acoustic signals. The movement aids can be designed, for example, as patient elevators, Segways, bicycles, electric cars, other vehicles such as cars, buses and trucks. The operators of the movement aid and/or other road users are informed or warned about the traffic situation, in particular by means of acoustic and/or optical signals. In the method according to the invention, the intended spatial movement, such as the speed curve with respect to a coordinate system, can also be influenced automatically, at least in a supportive manner, by braking, accelerating and steering. Devices that reduce the consequences of inappropriate movements in traffic, especially accidents, such as belt tensioners, window regulators, airbags and/or adjusting devices for hoods, can also be influenced or activated in their functioning. In particular, at least one acoustically active road user recognizes at least one characteristic feature of the acoustic signals of the initialization emissions of at least one other acoustically active road user and/or at least one other sound source located in the vicinity of the acoustically active road user and then sends it after a delay time emits an acoustic reaction emission for a limited time, which preferably has a clear relationship to the initialization emission. At least one characteristic feature, such as the signal strength and/or the time course of the signal strength (for example in the form of a pulse pattern) and/or the time course of the signal frequency or the signal frequency mixture, is used. According to the invention, the road user who sent out the initialization transmission reacts to receiving at least one reaction transmission in the same way by sending out another reaction transmission. Both the road users who actively emit acoustics and those road users who only receive and evaluate the acoustic signals occurring in the environment can determine the position and/or the movement of road users who actively emit acoustics and/or passively reflecting objects from the environment emitted initialization emissions use the emitted reaction emissions and optionally also the further reaction emissions sent out and generated in response to the reception of reaction emissions as well as the resulting echoes from passively reflecting objects.

Preferably, in at least one evaluation of the acoustic signals of the initialization emissions of an initializing traffic participant and/or the reaction emissions of at least one of the two traffic participants, carried out to determine the relative distance and / or the relative movement between at least two road users, at least one characteristic feature of the acoustic signals of these initialization emissions and / or these reaction emissions, such as preferably the signal strength and / or the time course of the signal strength (for example in the form of a pulse pattern) and / or the signal frequency and / or the time course of the signal frequency or the signal frequency mixture of the corresponding acoustic signals.

In the method according to the invention, the road user generating the initialization emissions also knows what delay time between the time when the at least one characteristic feature of the acoustic signals is fulfilled Initialization emissions and the start of the reaction emissions of the road users receiving the acoustic signals of the initialization emissions. This allows the initializing road user to deduce the distance between the two road users from the total running time of the acoustic signals of the initialization emissions and the corresponding reaction emissions.

In order to reduce the probability of collision between the reaction emissions of several road users who react in particular to the same emissions from a road user, a few different delay times (delays) from a set of agreed delay times are preferably used for these reaction emissions.

In order to reduce the probability of collision of the acoustic signals of the reaction emissions of several road users, in a particularly advantageous embodiment of the method according to the invention, the signal duration of the acoustic signals of the reaction emissions of at least one road user is smaller than a predetermined fraction of the signal duration of the acoustic signals of the initialization emissions of the initializing road user (first road user ).

In particular, at least one signal duration and/or at least one frequency or at least one frequency curve of the acoustic signals of the reaction emissions of at least one road user is/are known to at least the road users receiving the acoustic signals of these reaction emissions.

In other words, in particular even if at least one characteristic feature of the acoustic signals of the initialization emissions of a road user is permanently fulfilled, only time-limited reaction emissions of acoustic signals are generated by the receiving road users. In particular, the proportionate transmission duration of such reaction broadcasts can be less than 1%. For example, if the at least one characteristic feature of the acoustic signals of an initialization emission that must be fulfilled is the signal strength, a continuous sound source generating the initialization emission can cause a reaction emission that includes an occasional short-term replay of the continuous sound source.

In order to achieve a further reduction in the probability of collision between the reaction emissions of several road users who react in particular to the same emissions from a road user, a few different reaction emission durations from a set of agreed reaction emission durations (replay durations) are preferably used for these reaction emissions.

In a further preferred embodiment of the method according to the invention, information relating to these reaction emissions is modulated into the acoustic signals of the reaction emissions of at least one road user, in particular information comprising the delay time used for these reaction emissions and/or the signal duration and/or the signal frequency or the signal frequency curve of the corresponding acoustic signals.

In a particularly preferred embodiment of the method according to the invention, the acoustic signals of the reaction emissions of at least one road user have a clear relationship to the initialization emissions of the initializing road user. Preferably, the signal strength and/or the signal curve of the acoustic signals of the reaction emissions of at least one road user has a clear relationship to the signal strength and/or to the signal curve of the acoustic signals of the initialization emissions of the initializing road user, which in particular have a time-varying frequency curve.

The acoustic signals of the reaction emissions preferably each comprise a predetermined signal section of the acoustic signals of the initialization emissions, the predetermined signal sections being in a time-inverse order (colloquially “playing backwards”) or in an unchanged time order at the same playback speed and/or at a different playback speed ( and therefore with a different signal frequency than the acoustic signals of the initialization emissions from the initializing road user). The changed playback speed is implemented in particular by using a different sample rate compared to recording.

The use of a different playback speed for the acoustic signals of the reaction emissions has the advantage that the acoustic signals of the reaction emissions can be technically easily separated from one another by filtering from the acoustic signals of the initialization emissions. In particular, a signal form determined by coding is used for the signal form of the acoustic signals of the reaction emissions det, which is realized, for example, by means of an assignment table or by algebra.

In order to easily separate the acoustic signals of the reaction emissions from several road users who react in particular to the same emissions from a road user, a few different ones from a set of agreed playback speeds are used for the playback speeds of the acoustic signals of these reaction emissions.

In order to achieve a further reduction in the probability of collision between the reaction emissions of several road users reacting in particular to the same emissions from a road user, the delay time, the proportionate transmission duration, the reaction emission duration, the strength of the signal, the playback order, and / or the playback speed are preferably dependent on the degree of use of the acoustic medium by other road users and/or by other sound sources and/or depending on the own speed of the emitting road user and/or on the relative position and/or on the relative movement of other objects and/or road users.

In the method according to the invention, at least one receiving road user records the acoustic signals of the active emissions of at least one other road user, preferably by means of at least two receiving systems, and evaluates the differences in the received acoustic signals of the active emissions with regard to relative position and/or relative movement, in particular based on the transit time differences Doppler shift, and/or the signal strength. In addition, this road user can preferably also evaluate the echoes that arrive at him, that is, also the acoustic signals that arise after acoustic emissions as a result of passive reflection on reflecting objects. From the signal changes during the transmission path, either at least the spatial relationship between the transmitting and receiving road users and/or the passively sound-reflecting objects is determined and/or a statement is made about the relative movement between the road users and/or the passively sound-reflecting objects and/or on the Traffic conditions between the road users, in particular the position and/or the shape of the other road users or stationary objects in between, such as trees, and/or the condition of the road, etc. are inferred.

In particular, each road user can both carry out initialization emissions of acoustic signals and respond to the received acoustic signals of active emissions from other road users with response emissions of acoustic signals.

According to the invention, a vehicle assistance system is also provided with a device according to the invention for determining the relative distance and/or the relative movement between at least two road users, in particular between at least two vehicles.

Brief description of the drawings

• 1 eine schematische Darstellung einer Verkehrssituation, in der ein erster, initialisierender Verkehrsteilnehmer Initialisierungsaussendungen von akustischen Signalen erzeugt, die wiederum bei einem zweiten, die akustischen Signale der Initialisierungsaussendungen empfangenden Verkehrsteilnehmer Reaktionsaussendungen von akustischen Signalen auslöst,
• 2 eine schematische Darstellung der Lage des möglichen Dopplerbandes der akustischen Signale einer Reaktionsaussendung eines reagierenden Verkehrsteilnehmers im Vergleich zu der Lage des Dopplerbandes der ursprünglichen akustischen Signale der Initialisierungsaussendung des initialisierenden Verkehrsteilnehmers für eine gegenüber der Aufnahmegeschwindigkeit 1,5-fachen Abspielgeschwindigkeit.

Embodiments of the invention are described in detail below with reference to the accompanying drawings. In the drawings is:

• 1 a schematic representation of a traffic situation in which a first, initializing road user generates initialization emissions of acoustic signals, which in turn triggers reaction emissions of acoustic signals from a second road user who receives the acoustic signals of the initialization emissions,
• 2 a schematic representation of the position of the possible Doppler band of the acoustic signals of a reaction emission from a reacting road user in comparison to the position of the Doppler band of the original acoustic signals of the initialization emission of the initializing road user for a playback speed that is 1.5 times the recording speed.

Embodiments of the invention

1 illustrates the method according to the invention (autoreplay protocol) as an example of a traffic situation in which only two road users T1 and T2 are shown out of many possible acoustically active road users. The first road user T1 comprises a signal generator 10 for generating acoustic signals 11, a transmitting device 20 for sending acoustic signals, a receiving device 30 for receiving acoustic signals 31, and at least one evaluation device 40 for evaluating the received acoustic signals 31.

The second road user T2 includes the device 100 according to the invention with at least one receiving device 50 for receiving of acoustic signals 51, a transmitting device 60 for sending acoustic signals, and at least one control device 70 for detecting the incoming acoustic signals 51 based on features characterizing the acoustic signals 51 and for causing acoustic signals 71 to be sent out as a result of the arrived signals 51 after a delay time TD. The control device 70 is in particular designed in such a way that the acoustic signals 71 generated by the second road user T2 are generated and sent out as a reaction of the second road user T2 to the acoustic signals 51 received and generated by the first road user T1 or an acoustic signal source located in the surrounding area were clearly distinguished by the first participant T1 from the classic echoes from passively reflecting objects and were therefore recognized as reaction emissions 71 from the second road user T2, which were made in response to the active emissions of acoustic signals 11 from the first road user T1.

Optionally, the road user T1, who had generated the original initialization emission 11, can also contain a control device (not shown) which, depending on the signals 31 received by means of the receiving device 30, generates further reaction emissions (not shown) according to the invention, which are also from those in the environment Road users, such as road user T2, are received and evaluated. The generated additional reaction emissions can also preferably be linked to other received acoustic signals and/or to other signals exchanged via other media, which characterize the presence and movement behavior of other road users and/or of passively reflecting objects, by means of sensor data fusion.

Furthermore, in addition to the first road user T1, the second road user T2 can also have an evaluation device (not shown) for evaluating the acoustic signals 51 received by the receiving device 50. The sound medium 80, via which the acoustically communicating road users T1, T2 are connected to one another, is shown hatched.

In the 1 TP1 is the pulse duration of the acoustic signals 11 emitted by the first road user T1 by means of the transmitting device 20. T12 denotes the time required for the transmission of the acoustic signal 11 of the first road user T1 until the control device 70 begins to recognize the second road user T2. Furthermore, TP1 is the pulse duration of the acoustic signals 51 emitted by the first road user T1 or an equivalent signal source (not shown) by means of the transmitting device 20 and received by means of the receiving device 50 of the second road user T2. TP2 further denotes the pulse duration of the acoustic signals 71 generated by the control device 70 of the second road user T2 in response to the received acoustic signals 51 of the emissions from the first road user T1. TD denotes the delay time between the beginning of the recognition of the acoustic signals 51 emitted by the first road user T1 using the transmitting device 20 and received by the second road user T2 using the receiving device 50 and the triggering of the reaction emissions of the acoustic signals 71 of the second road user T2 passes. Furthermore, the reference symbol T21 denotes the time that elapses between the start of the transmission of the acoustic signals 71 generated by the second road user T2 and the start of reception by the receiving device 30 of the first road user T1. The pulse duration of the acoustic signals 31 emitted by the second road user T2 and received by means of the receiving device 30 of the first road user T1 is marked TP21.

In a preferred embodiment, the control device 70 controls the sending of the reaction emissions 71 based on the received signals 51 based on characteristics of the received signals 51 of the initialization emissions, such as the signal strength, the time behavior of the signal strength (for example in the form of a pulse pattern) and / or the time course the signal frequency or the signal frequency mixture. In a preferred further developed embodiment, the optionally additionally present control device (not shown) can be designed to send further reaction emissions (not shown) from the road user T1, who had originally generated the initialization emissions 11, in response to the reception of the acoustic signals evaluated on the basis of characteristic features 31 to generate the reaction emissions 71. Due to the equivalence to the previous preferred embodiment with regard to the control device 70, the further developed embodiment mentioned with regard to the additional control device (not shown) will no longer be discussed separately below.

The initialization signals 11 can optionally not come from the road user T1, but from another sound in the acoustic environment source, originate. The initialization signals 11 can also include functional sound, such as engine noises or the squealing of brakes, or other acoustic signals, such as the beeping of traffic lights, footstep or driving noises, noises from fans on buildings, construction noise.

In a preferred embodiment, the control devices 70 and/or the optional additional control devices are preferably designed to limit the duration TP1 or TP2 of the emitted acoustic signals 11, 71 and/or the frequency with which the acoustic signals 11, 71 are emitted , for example even if the characteristic features of received acoustic signals 31, 51 are fulfilled for a long time or even permanently. The advantage here is that the sound medium 80 is only used partially, and thus the probability of collision with acoustic signals that come from emissions from other actively emitting road users and/or with echoes that arise as a result of reflections of acoustic signals on passively reflecting objects is reduced. The ratio of broadcast duration to broadcast breaks of 1% has proven successful so far. If many road users T1, T2 use one and the same sound medium 80, the many acoustic signals 31, 51 exchanged between the road users T1, T2 and the associated echoes contain so much, mostly redundant, information that reliable environmental monitoring is possible even in the case of a ratio from transmission durations to transmission pauses per electro-acoustic converter from well under 1% to under 0.1% is possible. Even for scenes that change only slowly, such as is common when slowly driving into a parking space, a small transmission frequency is usually sufficient. However, at high driving speeds and in particular when only a few acoustically active road users T1, T2 acoustically sound the medium 80, there is also a greater frequency of acoustic emissions, in particular from those electro-acoustic converters (not shown separately), whose orientation is predominantly along the expected route runs, makes sense. This applies in particular if the sound medium 80 can be divided, for example by frequency, code and/or signal strength multiplexing. Under these circumstances, an emission frequency of more than 10% per electro-acoustic converter can also make sense.

In a very preferred embodiment, the delay time TD between the beginning of the arrival of an initialization signal 51 and the beginning of the emission of a reaction signal 71 is independent of the signal strength and independent of a signal change as a result of a Doppler shift. Furthermore, this delay time TD is known to all road users T1, T2 who use the acoustic emissions according to this method according to the invention or autoreplay protocol to determine the position and/or movement of other road users T2, T1. In this way, each road user T1, T2, who receives the acoustic signals exchanged in the sound medium 80, can use the signal transit times, in particular between an initialization emission 11 and a reaction emission 71, when there are only two acoustically active road users T1, T2 in the sound medium 80, respectively also from the signal transit times between reaction emissions 71, if there are more than two acoustically active road users T1, T2 in the sound medium 80, on the spatial relationships between the acoustically active road users T1, T2 and / or between the passively reflecting objects (not shown), which are located in the formwork medium 80, conclude.

In a further preferred embodiment, the signal strength of the initialization emission has a fixed value or several signal strength values that are clearly distinguishable from one another and known to all road users T1, T2, at least in the main acoustic beam direction of an electro-acoustic converter.

The spatial distribution of the signal strength with respect to the electro-acoustic converter is referred to as the directional characteristic. In a further preferred embodiment, the directional characteristic of a sending road user T1, T2 is known to at least one receiving road user T2, T1. This is achieved, for example, by all electro-acoustic converters (not shown separately) using the same directional characteristic, or by the fact that in the exchanged messages, in particular in the exchanged acoustic messages, the information about the directional characteristic used by the sending electro-acoustic Transducer (not shown separately) and/or via the transmitted signal strength.

In a further preferred embodiment, the ratio of the signal strength of the received signals 51 of the initialization emissions and the received acoustic signals 31 of the associated reaction emission 71 and / or a further reaction emission (not shown) generated in response to a received reaction emission 71 changes according to rules that at least are known to some road users T1, T2. Furthermore, this ratio preferably changes independently of the signal change as a result of a Doppler shift. Furthermore, information is preferably included in the reaction emissions 71 nen about the strength of the received signal 51 of the initialization emissions. In a preferred embodiment, the ratio between the signal strengths of the initialization emission 11 and the associated reaction emission 71 or the further reaction emissions (not shown) generated in response to received reaction emissions 71 is fixed. In this implementation variant, the probability of collision of the reaction emissions 71 decreases as the signal strength of the received acoustic signals 51 of the initialization transmission decreases, and the influence of the transmission attenuation between the two road users T1, T2 is already present in the received signal of the road user T1, who had broadcast the initialization transmission 11 square included as information.

In an alternative implementation variant, the reaction emission 71 is always sent out with the greatest possible signal strength. The collision probability of the reaction emissions 71 is not influenced by the signal strength of the received acoustic signals 51 of the initialization emission; the transmission range is higher compared to the aforementioned implementation variant because the influence of the transmission attenuation between the two road users T1, T2 is only contained simply and not squarely.

Given known transmission properties of the transmission medium 80, geometric relationships between the road users can be inferred from the signal strength in one of the aforementioned implementation variants, in particular because the electro-acoustic transducers used in the sensors are usually characterized by a directional characteristic. Under these conditions, the overall attenuation of the transmitting and receiving electro-acoustic transducers can already be determined solely from the received signal strength of a transmitted signal 11, 71, which is recorded by a road user T1, T2 with only one receiving electro-acoustic transducer become. If the receiver 30, 50 comprises at least two receiving electro-acoustic transducers (not shown separately) and the two electro-acoustic transducers are separated by transit time, the spatial orientation of the transmitting signal can be determined from the different strengths of the received signals in conjunction with the different transit times Electro-acoustic converter of the sending road user T1, T2 to the receiving electro-acoustic converter of the road user T2, T1 of which the directional characteristic is known. If the position of the transmitting electro-acoustic transducer on the transmitting road user T1, T2 is known, the spatial relationship including the orientation of the electro-acoustic transducers to one another and thus the road users T1, T2 to one another can be determined using a message alone .

If the scene does not change or changes only negligibly slowly, subsequently exchanged acoustic information contains the spatial relationships of the road users T1, T2 located in the sound medium 80 equivalently as redundant information, otherwise as new information about the changing spatial conditions.

In a further preferred embodiment, the signals 31 of an initialization emission 11 received through the transmission in the sound medium 80 and/or the signals 51 of a reaction emission 71 received through the transmission in the sound medium 80 are evaluated based on characteristic features such as the signal strength.

For example, if the signal strength of the acoustic signals 51 received by the road user T2 from the initialization emission of the road user T1 or a sound source located in the acoustic environment exceeds a predetermined threshold, which is set, for example, depending on the signal strength of the noise, the road user T2 records this acoustic signal 51 in a particularly preferred embodiment by scanning as a discrete-time signal. After a fixed duration TD, which can have different lengths TD1, TD2, the second road user T2 sends out at least one fixed time excerpt, for example the beginning of at least one of the acoustic initialization signal 51 previously received and recorded by the road user T2. In particular, the Signal section 71 to be sent is amplified, preferably in reverse order, which means that the last received signal section is sent first. This is preferably done at a different playback speed, which means that the signal section 71 to be transmitted is sent at a different frequency. This in turn can be separated from the acoustic signals 11 of the emissions from the first road user T1 using filtering with little effort.

In a very advantageous embodiment, the reaction emissions 71 from the road user T2 and/or from at least one other road user (not shown) have a clear relationship to the initialization emissions from the road user T1. For example, a signal section of the emissions from the road user T1 can be shown in the reaction emissions 71 are reproduced in a time-inverse order (colloquially “playing backwards”) or in an unchanged time order and optionally at the same playback speed or at a different playback speed and thus in a different frequency position than the frequency position emitted by the road user T1. Saving signal sections can preferably be achieved by scanning. Furthermore, playback in a changed frequency position can then preferably be realized by means of a changed playback speed of the sample values. Alternatively, the signal form used in the reaction emissions 71 is determined by coding, which can be implemented, for example, by means of an assignment table or by algebra.

According to the invention, by varying the sampling frequency when transmitting in relation to the sampling frequency when receiving, the frequency position and the pulse duration of the reaction emissions 71 of the road users who react to at least one received initialization signal (initialization message) 51, such as the road user T2, can be varied. For example, by sending out the acoustic signals 71 of the reaction emissions of the second road user T2 twice as fast, the sound medium 80 is only required for half as long as if the same signals 71 were sent out at the playback speed at which they were recorded. If, in addition to the road users T1, T2, there are also other road users (not shown) in the medium 80, who, according to the invention, initiate the sending of reaction emissions 71 or further reaction emissions (not shown) based on an evaluation of the characteristic features of the received signals 51, 31, then Due to the halving of the respective use of the medium 80, the probability of collision of the reaction emissions in the medium 80 is reduced. The use of a double signal frequency leads to a smaller range of this reaction signal 71 or a further reaction signal (not shown) due to the frequency-dependent spatial attenuation and thereby also to a reduction the spatial collision probability of reaction emissions. In addition, thanks to the doubling of the signal frequency of the acoustic signals 71 of the reaction emissions compared to the acoustic signals 11 of the initialization emissions, these can be separated from one another more easily using frequency filters. The same applies to reaction emissions (not shown) from road user T1 as a result of initialization emissions (not shown) from road user T2.

Thanks to the firmly agreed delay time TD, collisions of reaction emissions can only occur for those road users who are at the same distance from the road user T1 initiating the acoustic exchange. If road users at the same distance move at different relative speeds, the collision effect is reduced thanks to the Doppler effect.

Thanks to the firmly agreed delay time TD, the road user T1 who initiated the initialization transmission can determine the distance between the two road users T1, T2 at the moment of signal exchange from the time between the time the initialization transmissions are generated and the time of receipt of the associated reaction transmission .

Thanks to the evaluation of acoustic signals based on the simple characteristic feature “signal strength”, the Doppler information contained in the signal about the relative movement of the road users (e.g. vehicles) T1, T2 to one another is preserved.

Thanks to the use of signal strength as a simple characteristic feature when evaluating received signals 51, 31, interoperability is easily possible. The procedure is easy to implement. To implement the method according to the invention, the reacting road users T1, T2 and/or the reacting other road users (not shown) do not require any knowledge about the internal structure of the initialization transmission 11 sent out, in particular not about the time course of the signal frequencies or about the time course of the signal amplitude . An easily implemented threshold switch alone determines the time from which an incoming signal 51, 31 is recorded after the signal strength has exceeded a threshold value once. The storage duration and the delay time TD can be determined using easily implemented time measuring devices. After the agreed delay time TD has expired, the stored signal is sent out again.

Interoperability of different processes, for example implemented by different manufacturers, is possible. For example, the method according to the invention works independently of the type of modulation of the initialization signals 11. For example, one system can use inexpensive amplitude modulation, or even amplitude keying, while other systems can use frequency shift keying or even m-ary frequency modulation or frequency modulated signals with continuous frequency response or noise-like signals or use phase shift keying, such as quadrature amplitude modulation. A road user, such as road user T2, who generates a reaction transmission 71 (replay) to any initialization transmission modulated in this way, does not require any knowledge of the type of modulation used. This also enables upward compatibility between different systems. For example, a system that itself only uses amplitude keying as the type of modulation of an initialization transmission 11 can also generate a reaction transmission (replay) to the reception of signals modulated in a manner similar to noise signals.

In a preferred embodiment, the signal frequency changes continuously over time, at least in a period of time of the initialization emission, that is to say that the initialization emission is chirp-modulated during the said period of time.

Thanks to the use of the signal strength as a simple characteristic feature in the evaluation of received signals 31, 51, the method described here can preferably also generate a reaction emission 71 to the arrival of acoustic signals that were not explicitly generated as measurement signals for environmental monitoring, among other things Include engine noises, impact noise, squeaks from bicycles, for example, or acoustic signals from traffic lights. This effect enables other road users, such as road user T2, to orientate themselves not only on the basis of such initialization emissions 11, which are explicitly sent out as measurement signals for environmental monitoring, and on the basis of the resulting echoes from passively reflecting objects, but also on the basis of reaction emissions from other road users, such as T1 , and the resulting echoes from passively reflecting objects. In this way, the medium 80 used, in which the sound propagates, is measured with a wealth of signals with just a few emissions 11, 71, which, thanks to the mostly redundant information contained, enable a rapid, reliable determination of the position and movement of the objects in the medium 80 enable road users T1, T2 and objects located, even if only a few road users, such as road user T2, are involved by actively sending out reaction messages 71. It is also possible for those road users who do not actively transmit but only evaluate the incoming acoustic signals, such as road user T2, to determine the position and movement of the other road users in the medium 80, such as road user T1, and themselves to determine objects otherwise located in medium 80.

The use of a combination of several characteristic features (signal properties), such as the signal strength and / or the time course of the signal strength (for example in the form of the frequency of occupancy of the medium 80) and / or the time course of the signal frequency or the signal frequency mixture when evaluating the received Signals 51, 31 is possible. For example, reaction broadcasts 71 can be generated more frequently to such initialization broadcasts 11. Such more frequently generated reaction emissions 71 can in particular be played back at a different playback speed and/or generated with a different delay time TD and/or have a different transmission duration TP2 and/or have a different playback order if they are preferably in addition to, for example, a minimum signal strength have special additional signal properties such as a special signal frequency curve.

The characteristic features of the reaction emissions 71 realized in this way therefore have properties that are easy to understand. Thus, the total running time between the transmission of the initialization transmission 11 and the reception of the reaction transmission 71, taking into account the delay time TD known to all road users T1, T2, is a measure of the distance between the road users T1, T2. When taking into account the rules of the changed playback speeds known to all road users T1, T2, the frequency changes are a measure of the relative movement of the road users T1, T2 to one another and the change in signal strength is a measure of the orientation of the road users when taking into account the current propagation attenuation in the medium 80 (communication partner) T1, T2 to each other.

In order to avoid collisions of the reaction emissions with reflections from non-active, that is, from reflecting objects, either a long delay time TD should be used, so that all echoes from potentially distant objects are already closer to the receiver 30 and in particular at least one signal form of the actively emitted acoustic ones Signals 71 of the reaction emissions is used, which differs significantly from the signal shape of the echoes from passively reflecting objects. The acoustic signals 71 of the reaction emissions can, for example, be based on the time course of the signal frequency in the case of frequency-modulated signal formats men and/or can be distinguished from the echoes of passively reflecting objects based on the signal frequency, which can be generated in particular by changing the playback speed.

For good signal separation between the acoustic signals 11 from initialization emissions and the acoustic signals 71 from reaction emissions through frequency filters, a smaller frequency shift or change in the playback speed is sufficient for some applications. If, for example, there are two vehicles T1, T2 with absolute speeds of 60 km/h, i.e. 17 m/s, in an area of the sound medium 80, the maximum relative speed of the two vehicles T1, T2 that meet each other can be 34 m/s, which is one Doppler shift of approximately 10% of the signal frequency of the acoustic signals 11 of the initialization emissions at the reaction receiver T1.

2 shows the position of the possible Doppler band DR of a reaction emission at the reacting road user (reactor) T2 in comparison to the position of the Doppler band DI of the corresponding initialization emission at the originally initializing road user T1 at a 1.5-fold playback speed.

In this context, the ratio of playback speed to recording speed in reactor T2 is referred to as relative playback speed RA.

It becomes clear that both bands DI, DR do not overlap, even when considering extreme values. Things look even better for the relationship between an initialization emission and an associated reaction emission, since both bands change in the same direction.

In traffic situations in which only a few acoustically active road users T1, T2 have to share an area of the sound medium 80, it is also recommended to send out the acoustic signals of the reaction broadcasts at a lower playback speed, which corresponds to a shift towards lower signal frequencies. Due to the small number of road users T1, T2, the probability of collision of the reaction emissions is low despite the longer pulse duration compared to the initialization emissions. Choosing the lower signal frequency can be advantageous if higher ranges have to be achieved, as the spatial attenuation increases with the signal frequency.

Alternatively, changing the signal frequencies makes sense to avoid interference. This applies both to the initialization emissions from the initializing road user T1 and to the reaction emissions from the reacting road user T2.

The method is therefore preferably carried out in such a way that the choice of the signal frequencies of the initialization emissions as well as the relative playback speed RA during replay take place in a situation-adapted manner, but in such a way that the respective road user (communication partner) T1, T2 makes the change based on previously agreed rules of acoustic signals. For example, this is achieved by selecting only clearly distinguishable levels of the references contained in the reaction transmission 71 to the initialization transmission 11, in particular the relative playback speed, and/or the different delay duration TD and/or the signal length.

If one takes into account the fact that a road user T1, T2 usually records the active emissions of at least one other road user T2, T1 with at least two reception systems that are spatially distributed on the road user T1, T2 during acoustic environment detection, then the spatial differences can be used of the received emissions, in particular based on the transit time differences and/or the signal strength and/or the signal changes during the transmission path, at least the spatial relationship between the transmitting and the receiving road users T1, T2 are determined, a statement about the relative movement between the transmitting and the receiving Road users T1, T2 are made on the traffic conditions between the sending and the receiving road users T1, T2, in particular on the position and / or the shape of the other road users in between and / or stationary objects, such as trees, and / or on the Road condition, can be concluded.

In a preferred embodiment, at least one road user T2, in which several electro-acoustic transducers (not shown separately) are aligned with an area of the medium, does not send out a reaction emission 71 via each electro-acoustic transducer. For example, after receiving an initialization transmission 11, a corresponding reaction transmission 71 can be sent out via the electro-acoustic converter, via which the acoustic signals 51 of the initialization transmission with the greatest signal strength were received, and simultaneously or with a time delay, that is, after a different delay time TD, at least one further corresponding reaction emission 71 via the electrical Acoustic transducer is sent out, via which the acoustic signals 51 of the initialization transmission were received with the lowest signal strength. Other combinations are possible.

In a further preferred embodiment, at least one road user of the road users T1, T2 located in the medium 80 alternately takes on various of the previously mentioned functions, that is to say that this road user, for example, once acts as the initiating road user (initiator) T1 of the acoustic exchange and another time behaves as a reacting road user (reactor), such as the road user T2, who reacts with reaction emissions 71 to the reception of the acoustic signals 51 of an initialization transmission. In a preferred embodiment, an initiating road user (initiator) T1 confirms the receipt of the acoustic signals 31 of a reaction transmission 71 previously sent by a reacting road user (reactor) T2, also by sending a further reaction transmission (not shown). In this way, both the initiating road user T1 receives confirmation that the reacting road user T2 has received the acoustic signals 51 of his initialization transmission, and the reacting road user T2 receives confirmation of the receipt of the acoustic signals 31 of his reaction transmission by the initiating road user T1. Such confirmed transmissions help to meet the increasingly increasing reliability requirements for environmental monitoring.

In addition to the information for implementing the method according to the invention (replay protocol), both the reaction emissions 71 and the initialization emissions 11 can also contain further information, such as the driving dynamics state of the vehicle and/or vehicle identification.

Claims (5)

Method for determining the relative distance and/or the relative movement between at least two road users (T1, T2), in particular between at least two vehicles, based on the reception of acoustic signals (51) resulting from initialization emissions in the form of acoustic signals (11). come from a first road user (T1), reaction emissions are triggered by a second road user (T2) in the form of acoustic signals (71), which are received and evaluated by the first road user (T1), the reaction emissions of the second Road user (T2) after the expiry of at least one delay time (TD) known to the road users (T1, T2), which is set so long that acoustic signals received by the first road user (T1), which consist of passive reflections of the initialization emissions of the first Road user (T1) originate from surrounding objects, have no influence on an evaluation carried out by the first road user (T1) of the reaction emissions (71) of the second road user (T2) received by means of at least one receiver (30), characterized in that based on the first road user (T1) received acoustic signals (31) of the reaction emissions of the second road user (T2) reaction emissions of acoustic signals from the first road user (T1) are triggered after the expiration of at least one delay time known to the road users (T1, T2) and of such a long duration that the acoustic signals received by the second road user (T2), which come from passive reflections of the acoustic signals of the reaction emissions of the first road user (T1) on surrounding objects, have no influence on one used by the second road user (T2) to determine the relative distance and / or the relative movement between the two road users (T1, T2) carried out evaluation of the acoustic signals of the reaction emissions of the first road user (T1) received by the second road user (T1, T2) by means of at least one receiver (50). Procedure according to Claim 1 , characterized in that the signal duration (TP2) of the acoustic signals (71) of the reaction emissions of at least one road user (T2) is smaller than a predetermined fraction of the signal duration (TP1) of the acoustic signals of the initialization emissions of the first road user (T1) and / or at least a signal duration (TP2) and / or at least one frequency or at least one frequency curve of the acoustic signals (71) of the reaction emissions of at least one road user (T2) is known to the road users (T1, T2). Method according to one of the preceding claims, characterized in that in the acoustic signals (71) of the reaction emissions of at least one road user (T2) there is information relating to these reaction emissions, in particular information comprising the at least one delay time (TD) used for these reaction emissions and/or the signal duration (TP2) and/or the signal frequency or the signal frequency curve of the corresponding acoustic signals can be modulated. Method according to one of the preceding claims, characterized in that in at least one evaluation of the acoustic signals (11) of the initialization emissions of the first road user and/or the acoustic signals (71) of the reaction emissions of at least one road user (T2) at least one characteristic feature of the acoustic signals (11) of these initialization emissions and / or the acoustic signals (71) of these reaction emissions, in particular the signal strength and / or the time course of the signal strength and / or the signal frequency and/or the time course of the signal frequency or the signal frequency mixture of the corresponding acoustic signals is used. Method according to one of the preceding claims, characterized in that the signal strength and/or the signal course of the acoustic signals (71) of the reaction emissions of at least one road user (T2) has a clear relationship to the signal strength and/or to the signal course of the acoustic signals (11). the initialization emissions of the first road user (T1), which in particular have a time-varying frequency curve.

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