WO2007009833A1 - Method and circuit arrangement for precise distance measurement - Google Patents
Method and circuit arrangement for precise distance measurement Download PDFInfo
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- WO2007009833A1 WO2007009833A1 PCT/EP2006/062794 EP2006062794W WO2007009833A1 WO 2007009833 A1 WO2007009833 A1 WO 2007009833A1 EP 2006062794 W EP2006062794 W EP 2006062794W WO 2007009833 A1 WO2007009833 A1 WO 2007009833A1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
- G01S13/06—Systems determining position data of a target
- G01S13/08—Systems for measuring distance only
- G01S13/10—Systems for measuring distance only using transmission of interrupted, pulse modulated waves
- G01S13/103—Systems for measuring distance only using transmission of interrupted, pulse modulated waves particularities of the measurement of the distance
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/28—Details of pulse systems
- G01S7/285—Receivers
- G01S7/292—Extracting wanted echo-signals
Definitions
- the invention relates to a method according to the preamble of claim 1, as well as a circuit arrangement for carrying out the method according to claim 9.
- the technical measurement of distances is often carried out by determining the echo time of a wave signal emitted by a measuring device and reflected by a target or a distant object. Often, this electromagnetic waves, such as in the
- the emitted signal In order to be able to determine the echo propagation time, the emitted signal must be suitably modulated.
- modulation types here are the pulse modulation, the sinusoidal amplitude modulation with possibly a plurality of modulation frequencies used sequentially, the frequency modulation, for example used in the FMCW-RADAR, and the pseudo-noise modulation. In the following, the pulse modulation is considered in more detail.
- Pulse modulation is used for example in PuIsLIDAR and PuIsRADAR.
- the carrier signal is modulated with a short, typically about 0.1 ns to 30 ns transmitting pulse. This arrives after the reflection at the destination after the echo delay ⁇ to the receiver.
- Evaluation circuit in the receiver has the task to estimate the echo delay ⁇ as accurately as possible and to calculate the distance d from the target or an object, knowing the propagation velocity c of the signal.
- the propagation velocity c of the signal is the speed of light in the case of the use of electromagnetic waves and the speed of sound in the case of the use of acoustic waves.
- the echo propagation time can be determined from this.
- times can only be measured with finite resolution. If, for example, a 150 MHz quartz oscillator and a digital counter are used for the time measurement, the time resolution is 6.67 ns, which is at
- Distance measurements using RADAR or LIDAR corresponds to a distance resolution of 1 m.
- the received echoes according to the prior art are not further processed analogously. They are digitized in a scanner and A / D converter, the sampling rate typically being in the nanosecond range.
- the matched filter can be arranged before or after the A / D converter.
- the pulse modulation in the received echo is represented by a few samples. Since the temporal resolution of the sampled values corresponds to the reciprocal of the sampling rate, the course of the analogue pulse containing the transmitted pulse reflected at the target must be Echo, for example, the timing and the height of the peak or the center of gravity of the samples are reconstructed mathematically in order to determine the echo delay with significantly increased resolution. In the above example, this means to obtain a mathematical resolution of, for example, 1 mm from echo samples having a distance resolution of 1 m.
- Generating an echo sample and associated echo signal having discrete echo sample times by sampling the received echo of the signal at discrete sampling intervals at a finite sampling rate; comparing the echo signal with a stored reference signal corresponding to the shape of the transmitted signal, by altering the reference signal parameters reference signal amplitude and reference signal phase shift determining those reference signal parameters for which the greatest similarity between reference signal and echo signal is achieved,
- the invention enables the highly accurate measurement of echo propagation times or of distances without the finite sampling rate or a violation of the sampling theorem leading to systematic errors.
- the invention is based on the fact that the shape of the received echo of the transmitted signal is known as a reference signal.
- the reference signal is present either as a formula, or as a stored measured value sequence with a higher resolution that can be achieved by the sampling rate.
- the amplitude and the temporal position of this reference signal are selected so that they are as similar as possible to the samples of the actual reception echo, specifically in the sense of the least square error.
- the reference signal thus constructed and the echo have the same violations of the sampling theorem, whereby systematic errors are avoided in the beginning.
- the parameters of the reference signal provide the echo amplitude and the echo delay.
- Fig. 1 shows a schematic representation of a circuit arrangement for
- a controller 1 periodically excites the transmitter TX to deliver a pulse modulated wavy signal having the normalized envelope f (t).
- the echo of the signal reflected from a target G at a distance d has the envelope where A represents the amplitude of the echo and ⁇ the echo time.
- Sampling and A / D conversion in a combined sampler and A / D converter 2 at the sampling rate f a are digitized echo samples with associated, for example, continuous indexes Echo sampling times are available, which are buffered in a memory 3, for example, a first-in-first-out memory, FIFO.
- the sequence of echo samples and the associated echo sample times form the echo signal to be considered.
- the echo signal is compared with a stored reference signal corresponding to the shape of the transmitted signal.
- reference signal amplitude and reference signal phase those reference signal parameters are determined in which there is the greatest similarity between the reference signal and the echo signal. This is done by shifting the phase position, according to a time shift, as well as by raising or lowering the amplitude of the reference signal until the reference signal is brought into coincidence with all echo samples lying in the buffered portion of the echo signal.
- the exact echo amplitude and the exact echo time are determined.
- the distance to the target G is calculated in the last step.
- a rough target detection is first performed. To this end, it is observed whether the echo samples exceed a predetermined threshold and at which echo sample the index / peak characterizing the echo sample instant occurs.
- the echo signal is fed to a matched filter for this purpose. Thereafter, by comparison with a threshold value, the determination of the index / corresponding to the echo sampling instant of the respective echo sample, at which the echo samples have a maximum, is performed. Matched filters and the downstream circuit arrangement for coarse distance calculation are accommodated in a common circuit arrangement 4. Thereafter, a coarse value for the echo reception time / measured in whole sampling periods l / f a since the transmission time is available. In this case, the number / is an integer which characterizes the echo sampling instant determined by the temporal resolution of the sampled values or the reciprocal of the sampling rate at which the associated echo sample assumes a maximum.
- Echo samples in the sense of the least squares error is as similar as possible.
- the following steps are carried out: a) ⁇ / is varied in the range -0.5... + 0.5 around the coarse echo sample with index I. b) For each considered displacement ⁇ / becomes a hypothetical amplitude
- the distance d to the target G can then be calculated.
- the value A mess (Ai) in step b) corresponds to the target amplitude A.
- the invention is particularly industrially applicable to the manufacture and operation of distance measuring devices, such as for distance control, collision detection, lane detection or general environment detection by means of RADAR, LIDAR or ultrasound in motor vehicles.
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- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Radar Systems Or Details Thereof (AREA)
- Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
Abstract
The invention relates to a method for precise distance measurement by precise echo propagation time measurement of a sinusoidal, pulse-modulated signal. The inventive method is characterized by carrying out the following steps: generating and emitting the sinusoidal, pulse-modulated signal; receiving the echo of the signal reflected by a remote object; generating an echo scanning value and an echo signal comprising associated, discrete echo scanning times by scanning the received echo using a finite scanning rate; comparing the echo signal with a stored reference signal corresponding to the shape of the emitted signal, determining the reference signal parameters for which the greatest similarity between reference signal and echo signal is achieved by modifying the reference signal parameters of reference signal amplitude and reference signal phase shift; determining the precise echo propagation time using the reference signal parameter at which there is the greatest similarity between the received signal and the reference signal; and determining the distance of the object using the propagation rate and the echo propagation time of the signal. The invention also relates to a circuit arrangement for carrying out said method.
Description
Verfahren und Schaltunqsanordnunq zur genauen EntfernungsbestimmungMethod and circuit arrangement for accurate distance determination
Technisches Gebiet:Technical area:
Die Erfindung betrifft ein Verfahren gemäß dem Oberbegriff des Anspruchs 1 , sowie eine Schaltungsanordnung zur Durchführung des Verfahrens, gemäß Anspruch 9.The invention relates to a method according to the preamble of claim 1, as well as a circuit arrangement for carrying out the method according to claim 9.
Stand der Technik:State of the art:
Die technische Messung von Entfernungen erfolgt häufig durch eine Bestimmung der Echolaufzeit eines von einem Messgerät ausgesandten und von einem Ziel oder einem entfernten Gegenstand reflektierten wellenförmigen Signals. Häufig werden hierzu elektromagnetische Wellen, wie beispielsweise bei derThe technical measurement of distances is often carried out by determining the echo time of a wave signal emitted by a measuring device and reflected by a target or a distant object. Often, this electromagnetic waves, such as in the
Entfernungsmessung mittels RADAR oder LIDAR, oder akustische Wellen, wie beispielsweise bei der Entfernungsmessung mittels Ultraschall, verwendet.Distance measurement by means of RADAR or LIDAR, or acoustic waves, as used for example in the distance measurement by means of ultrasound.
Um die Echolaufzeit bestimmen zu können, muss das ausgesandte Signal geeignet moduliert werden. Verbreitete Modulationsarten sind hierbei die Pulsmodulation, die sinusförmige Amplitudenmodulation mit gegebenenfalls mehreren, sequenziell verwendeten Modulationsfrequenzen, die Frequenzmodulation, beispielsweise verwendet beim FMCW-RADAR, und die Pseudo-Noise-Modulation. Im Folgenden wird die Pulsmodulation genauer betrachtet.In order to be able to determine the echo propagation time, the emitted signal must be suitably modulated. Common modulation types here are the pulse modulation, the sinusoidal amplitude modulation with possibly a plurality of modulation frequencies used sequentially, the frequency modulation, for example used in the FMCW-RADAR, and the pseudo-noise modulation. In the following, the pulse modulation is considered in more detail.
Pulsmodulation wird beispielsweise bei PuIsLIDAR und PuIsRADAR angewandt. Bei der Pulsmodulation wird das Trägersignal mit einem kurzen, typischerweise etwa zwischen 0.1 ns bis 30 ns dauernden Sendeimpuls moduliert. Dieser gelangt nach der Reflektion am Ziel nach der Echolaufzeit τ zum Empfänger. EinePulse modulation is used for example in PuIsLIDAR and PuIsRADAR. In pulse modulation, the carrier signal is modulated with a short, typically about 0.1 ns to 30 ns transmitting pulse. This arrives after the reflection at the destination after the echo delay τ to the receiver. A
Auswerteschaltung im Empfänger hat die Aufgabe, die Echolaufzeit τ möglichst genau zu schätzen und daraus unter Kenntnis der Ausbreitungsgeschwindigkeit c des Signals die Entfernung d zum Ziel oder zu einem Gegenstand zu berechnen.
Die Ausbreitungsgeschwindigkeit c des Signals ist dabei im Falle einer Verwendung von elektromagnetischen Wellen die Lichtgeschwindigkeit und im Falle einer Verwendung von akustischen Wellen die Schallgeschwindigkeit.Evaluation circuit in the receiver has the task to estimate the echo delay τ as accurately as possible and to calculate the distance d from the target or an object, knowing the propagation velocity c of the signal. The propagation velocity c of the signal is the speed of light in the case of the use of electromagnetic waves and the speed of sound in the case of the use of acoustic waves.
Aus der Wiener Filter-Theorie und aus der Radartechnik ist das auch als Matched Filter bezeichnete, Optimalfilter bekannt. Es besitzt eine Impulsantwort, die der zeitlich rückwärts laufenden Sendeimpulsform entspricht. Aus Skolnik „Introduction to Radar Systems", McGraw-Hill, 1962, Kap. 9.2 Matched-Filter Receiver \si bekannt, dass der Spitzenwert des Ausgangssignals ein maximales Verhältnis zum vorhandenen Systemrauschen erreicht, wenn das empfangene Echo des Sendeimpuls auf ein solches Matched Filter gegeben wird. Dieselbe Eigenschaft besitzt auch der so genannte Korrelationsempfänger, bei dem das empfangene Echo mit dem gesendeten Signal korreliert wird.From the Wiener filter theory and from the radar technology is also known as the matched filter, known optimal filter. It has an impulse response which corresponds to the temporally backward transmission pulse form. From Skolnik "Introduction to Radar Systems", McGraw-Hill, 1962, Chapter 9.2 Matched Filter Receiver \ si known that the peak value of the output signal reaches a maximum ratio to the existing system noise when the received echo of the transmitted pulse to such a matched filter The same property is also possessed by the so-called correlation receiver, in which the received echo is correlated with the transmitted signal.
Wird der Zeitpunkt des Maximalwerts am Ausgang des Matched Filters oder des Korrelators genau gemessen, kann daraus die Echolaufzeit bestimmt werden.If the time of the maximum value at the output of the matched filter or the correlator is accurately measured, the echo propagation time can be determined from this.
In der Praxis können jedoch Zeiten nur mit endlicher Auflösung gemessen werden. Wird beispielsweise ein 150 MHz Quarzoszillator und ein digitaler Zähler zur Zeitmessung benutzt, so beträgt die Zeitauflösung 6,67 ns, was beiIn practice, however, times can only be measured with finite resolution. If, for example, a 150 MHz quartz oscillator and a digital counter are used for the time measurement, the time resolution is 6.67 ns, which is at
Entfernungsmessungen mittels RADAR oder LIDAR einer Entfernungsauflösung von 1 m entspricht.Distance measurements using RADAR or LIDAR corresponds to a distance resolution of 1 m.
Weiterhin werden die empfangenen Echos nach dem Stand der Technik nicht analog weiter verarbeitet. Sie werden in einem Abtaster und A/D-Wandler digitalisiert, wobei die Abtastrate typischerweise im Nanosekunden-Bereich liegt. Das Matched Filter kann hierbei vor oder nach dem A/D-Wandler angeordnet sein.Furthermore, the received echoes according to the prior art are not further processed analogously. They are digitized in a scanner and A / D converter, the sampling rate typically being in the nanosecond range. The matched filter can be arranged before or after the A / D converter.
Durch die Abtastung mit endlicher Abtastrate fa wird die Pulsmodulation beim empfangenen Echo durch wenige Abtastwerte dargestellt. Da die zeitliche Auflösung der Abtastwerte dem Kehrwert der Abtastrate entspricht, muss der Verlauf des den am Ziel reflektierten Sendeimpuls beinhaltenden, analogen
Echos, beispielsweise der Zeitpunkt und die Höhe des Spitzenwerts oder des Schwerpunkts aus den Abtastwerten rechnerisch rekonstruiert werden, um daraus die Echolaufzeit mit deutlich erhöhter Auflösung zu bestimmen. Im obigen Beispiel bedeutet dies, aus Echoabtastwerten mit 1 m Abstandsauflösung eine rechnerische Auflösung von beispielsweise 1 mm zu gewinnen.By sampling at finite sampling rate f a , the pulse modulation in the received echo is represented by a few samples. Since the temporal resolution of the sampled values corresponds to the reciprocal of the sampling rate, the course of the analogue pulse containing the transmitted pulse reflected at the target must be Echo, for example, the timing and the height of the peak or the center of gravity of the samples are reconstructed mathematically in order to determine the echo delay with significantly increased resolution. In the above example, this means to obtain a mathematical resolution of, for example, 1 mm from echo samples having a distance resolution of 1 m.
Da die empfangenen Echos häufig oberhalb der halben Abtastrate noch zumindest schwache Frequenzanteile besitzen, wird im Abtaster das Nyquist- Shannon-Abtasttheorem verletzt. Dadurch wird die rechnerische Rekonstruktion ungenau, und es werden systematische, über dem Abstand periodische Fehler in der Entfernungsmessung erzeugt. Hieraus folgt, dass nach dem Stand der Technik keine genaue Echolaufzeitmessung und damit auch keine genaue Entfernungsmessung möglich ist.Since the received echoes often still have at least weak frequency components above half the sampling rate, the Nyquist-Shannon sampling theorem is violated in the scanner. As a result, the computational reconstruction becomes inaccurate, and systematic, over the distance periodic errors in the distance measurement are generated. It follows that according to the prior art, no accurate echo time measurement and thus no accurate distance measurement is possible.
Offenbarung der Erfindung und deren Vorteile:Disclosure of the invention and its advantages:
Die Nachteile des Standes der Technik werden bei einem Verfahren der eingangs genannten Gattung vermieden durch die VerfahrensschritteThe disadvantages of the prior art are avoided in a method of the type mentioned by the method steps
- Erzeugung und Entsendung des wellenförmigen, pulsmodulierten Signals,Generation and dispatch of the wave-shaped, pulse-modulated signal,
- Empfangen des von einem entfernten Gegenstand reflektierten Echos des Signals,Receiving the echo of the signal reflected from a remote object,
- Erzeugung eines Echoabtastwerte und zugeordnete, diskrete Echoabtastzeitpunkte umfassenden Echosignals durch Abtasten des empfangenen Echos des Signals in diskreten Abtastintervallen mit einer endlichen Abtastrate, - Vergleich des Echosignals mit einem der Form des gesendeten Signals entsprechenden, gespeicherten Referenzsignal, wobei durch Veränderung der Referenzsignalparameter Referenzsignalamplitude und Referenzsignalphasenverschiebung diejenigen Referenzsignalparameter bestimmt werden, für die die größte Ähnlichkeit zwischen Referenzsignal und Echosignal erzielt werden,Generating an echo sample and associated echo signal having discrete echo sample times by sampling the received echo of the signal at discrete sampling intervals at a finite sampling rate; comparing the echo signal with a stored reference signal corresponding to the shape of the transmitted signal, by altering the reference signal parameters reference signal amplitude and reference signal phase shift determining those reference signal parameters for which the greatest similarity between reference signal and echo signal is achieved,
- Bestimmung der genauen Echoamplitude und der Echolaufzeit anhand der Referenzsignalparameter, bei denen die größte Ähnlichkeit zwischen Empfangssignal und Referenzsignal vorliegt, sowie
- Bestimmung der Entfernung des Gegenstandes anhand der Ausbreitungsgeschwindigkeit und der Echolaufzeit des Signals.Determining the exact echo amplitude and the echo time using the reference signal parameters, where the greatest similarity between the received signal and the reference signal, and - Determination of the distance of the object based on the propagation speed and the echo time of the signal.
Die Erfindung ermöglicht die hoch genaue Messung von Echolaufzeiten bzw. von Entfernungen, ohne dass die endliche Abtastrate bzw. eine Verletzung des Abtasttheorems zu systematischen Fehlern führen.The invention enables the highly accurate measurement of echo propagation times or of distances without the finite sampling rate or a violation of the sampling theorem leading to systematic errors.
Die Erfindung basiert darauf, dass die Form des empfangenen Echos des entsandten Signals als Referenzsignal bekannt ist. Das Referenzsignal liegt dabei entweder als Formel, oder als gespeicherte Messwertfolge mit einer höheren als durch die Abtastrate erzielbaren Auflösung vor.The invention is based on the fact that the shape of the received echo of the transmitted signal is known as a reference signal. The reference signal is present either as a formula, or as a stored measured value sequence with a higher resolution that can be achieved by the sampling rate.
Es werden die Amplitude und die zeitliche Position dieses Referenzsignals so gewählt, dass sie den Abtastwerten des tatsächlichen Empfangsechos möglichst ähnlich sind, und zwar im Sinne der kleinsten Fehlerquadratsumme. Dadurch weisen das so konstruierte Referenzsignal und das Echo dieselben Verletzungen des Abtasttheorems auf, wodurch systematische Fehler bereits im Ansatz vermieden werden. Die Parameter des Referenzsignals liefern die Echo- Amplitude und die Echolaufzeit.The amplitude and the temporal position of this reference signal are selected so that they are as similar as possible to the samples of the actual reception echo, specifically in the sense of the least square error. As a result, the reference signal thus constructed and the echo have the same violations of the sampling theorem, whereby systematic errors are avoided in the beginning. The parameters of the reference signal provide the echo amplitude and the echo delay.
Kurzbeschreibung der ZeichnungBrief description of the drawing
Fig. 1 zeigt eine schematische Darstellung einer Schaltungsanordnung zurFig. 1 shows a schematic representation of a circuit arrangement for
Durchführung des erfindungsgemäßen Verfahrens.Implementation of the method according to the invention.
Wege zur Ausführung der Erfindung:Ways to carry out the invention:
Eine Steuerung 1 regt periodisch den Sender TX zur Abgabe eines pulsmodulierten, wellenförmigen Signals mit der normierten Hüllkurve f(t) an. Das von einem Ziel G im Abstand d reflektierte Echo des Signals besitzt die Hüllkurve
wobei A die Amplitude des Echos und τ die Echolaufzeit darstellen. NachA controller 1 periodically excites the transmitter TX to deliver a pulse modulated wavy signal having the normalized envelope f (t). The echo of the signal reflected from a target G at a distance d has the envelope where A represents the amplitude of the echo and τ the echo time. To
Abtastung und A/D-Wandlung in einem kombinierten Abtaster und A/D-Wandler 2 mit der Abtastrate fa stehen digitalisierte Echoabtastwerte mit zugeordneten, beispielsweise durch fortlaufende Indizes / wiedergegebenen
Echoabtastzeitpunkten zur Verfügung, die in einem Speicher 3, beispielsweise einem First-In-First-Out-Speicher, FIFO, zwischengespeichert werden. Die Folge der Echoabtastwerte und der zugeordneten Echoabtastzeitpunkte bilden das zu betrachtende Echosignal.Sampling and A / D conversion in a combined sampler and A / D converter 2 at the sampling rate f a are digitized echo samples with associated, for example, continuous indexes Echo sampling times are available, which are buffered in a memory 3, for example, a first-in-first-out memory, FIFO. The sequence of echo samples and the associated echo sample times form the echo signal to be considered.
Anschließend wird das Echosignal mit einem der Form des gesendeten Signals entsprechenden, gespeicherten Referenzsignal verglichen. Durch Veränderung der Referenzsignalparameter Referenzsignalamplitude und Referenzsignalphasenverschiebung werden diejenigen Referenzsignalparameter bestimmt, bei denen die größte Ähnlichkeit zwischen Referenzsignal und Echosignal vorliegt. Dies geschieht durch Verschieben der Phasenlage, entsprechend einer zeitlichen Verschiebung, sowie durch Anheben oder Absenken der Amplitude des Referenzsignals, bis das Referenzsignal mit allen im zwischengespeicherten Abschnitt des Echosignals liegenden Echoabtastwerten in Deckung gebracht ist. Anhand der so gewonnenen Referenzsignalparameter wird die genaue Echoamplitude und die genaue Echolaufzeit bestimmt. Anhand der Echolaufzeit und der der Ausbreitungsgeschwindigkeit des Signals wird im letzten Schritt die Entfernung zum Ziel G berechnet.Subsequently, the echo signal is compared with a stored reference signal corresponding to the shape of the transmitted signal. By changing the reference signal parameters reference signal amplitude and reference signal phase shift those reference signal parameters are determined in which there is the greatest similarity between the reference signal and the echo signal. This is done by shifting the phase position, according to a time shift, as well as by raising or lowering the amplitude of the reference signal until the reference signal is brought into coincidence with all echo samples lying in the buffered portion of the echo signal. Based on the reference signal parameters obtained in this way, the exact echo amplitude and the exact echo time are determined. Based on the echo time and the propagation speed of the signal, the distance to the target G is calculated in the last step.
Bei einer weiteren Ausführungsform wird nach der Erzeugung des die Echoabtastwerte und zugeordneten Echoabtastzeitpunkte umfassenden Echosignals durch Abtasten des Echos mittels des kombinierten Abtasters und A/D-Wandlers 2 zunächst eine grobe Zieldetektion durchgeführt. Dazu wird beobachtet, ob die Echoabtastwerte einen vorgegebenen Schwellwert überschreiten und an welchem Echoabtastwert mit dem den Echoabtastzeitpunkt charakterisierenden Index / das Maximum auftritt.In another embodiment, after generating the echo signal comprising the echo samples and associated echo sample times, by sampling the echo by the combined sampler and A / D converter 2, a rough target detection is first performed. To this end, it is observed whether the echo samples exceed a predetermined threshold and at which echo sample the index / peak characterizing the echo sample instant occurs.
Das Echosignal wird hierzu einem Matched Filter zugeführt. Danach wird durch Vergleich mit einem Schwellwert die Bestimmung des dem Echoabtastzeitpunkt des jeweiligen Echoabtastwerts entsprechenden Indexes / durchgeführt, bei dem die Echoabtastwerte ein Maximum aufweisen. Matched Filter und die nachgeschaltete Schaltungsanordnung zur groben Entfernungsberechnung sind in einer gemeinsamen Schaltungsanordnung 4 untergebracht.
Danach steht ein in ganzen Abtastperioden l/fa seit dem Sendezeitpunkt gemessener Grobwert für den Echoempfangszeitpunkt / zur Verfügung. Die Zahl / ist hierbei eine ganze Zahl, welche den durch die zeitliche Auflösung der Abtastwerte bzw. den Kehrwert der Abtastrate bestimmten Echoabtastzeitpunkt charakterisiert, bei dem der zugehörige Echoabtastwert ein Maximum einnimmt.The echo signal is fed to a matched filter for this purpose. Thereafter, by comparison with a threshold value, the determination of the index / corresponding to the echo sampling instant of the respective echo sample, at which the echo samples have a maximum, is performed. Matched filters and the downstream circuit arrangement for coarse distance calculation are accommodated in a common circuit arrangement 4. Thereafter, a coarse value for the echo reception time / measured in whole sampling periods l / f a since the transmission time is available. In this case, the number / is an integer which characterizes the echo sampling instant determined by the temporal resolution of the sampled values or the reciprocal of the sampling rate at which the associated echo sample assumes a maximum.
Im nächsten Schritt werden die den Grobwert des Echoempfangszeitpunkts umgebenden , Echoabtastwerte Sι mit den Indizes i = {I-k,...,I+ k} mit k e Z, beispielsweise k = 5 sowie dem Echoabtastwert mit dem Index / einer Schaltung zur genauen Zielberechnung 5 zugeführt. In dieser Schaltung 5 wird die zusätzlich notwendige zeitliche Verschiebung Ai und die Amplitude A des Referenzsignals bestimmt, so dass das Referenzsignal den tatsächlichen, übergebenenIn the next step, the echo samples Sι surrounding the coarse value of the echo reception time are supplied with the indices i = {Ik,..., I + k} with ke Z, for example k = 5, and the echo sample with the index / circuit for accurate target calculation 5 , In this circuit 5, the additional necessary time shift Ai and the amplitude A of the reference signal is determined, so that the reference signal to the actual, transferred
Echoabtastwerten im Sinne der kleinsten Fehlerquadratsumme möglichst ähnlich wird. Hierzu werden die folgende Schritte durchgeführt: a) Δ/ wird im Bereich -0.5 ... +0.5 um den grobbestimmten Echoabtastwert mit dem Index I herum variiert. b) Für jede betrachtete Verschiebung Δ/ wird eine hypothetische AmplitudeEcho samples in the sense of the least squares error is as similar as possible. For this purpose, the following steps are carried out: a) Δ / is varied in the range -0.5... + 0.5 around the coarse echo sample with index I. b) For each considered displacement Δ / becomes a hypothetical amplitude
Amess(Δ/) berechnet zu:At ess (Δ /) calculates to:
Falls das Referenzsignal mit der Hüllkurve f(t) nur als gespeicherte Messwertfolge verfügbar ist, werden Referenzsignalabtastwerte von f(t) mit einer gegenüber der Abtastperiode Mfa um den Faktor N erhöhten zeitlichen Auflösung, beispielsweise N = 16 der Schaltung zur genauen Zielberechnung 5 als Tabelle zur Verfügung gestellt. Dies bedeutet, dass Δ/ im interessierenden Bereich -0.5 ... 0.5 um den Echoabtastzeitpunkt / herum insgesamt Λ/+1 verschiedene Werte annehmen kann. Ist derjenige diskrete Wert Aimin gefunden, für den die Fehlerquadratsumme e minimal wird, wird eine Nachverbesserung durchgeführt. Dazu werden die Werte der Fehlerquadratsumme e zusätzlich an den Nachbarstellen Δimin-1 und Δimin+1 betrachtet:If the reference signal with the envelope f (t) is available only as a stored measurement sequence, reference signal samples of f (t) with a temporal resolution increased by a factor N over the sampling period Mf a , for example N = 16 of the accurate target calculation circuit 5, are considered Table provided. This means that Δ / / can assume a total of Λ / + 1 different values in the region of interest -0.5 ... 0.5 around the echo sampling time / around. If the discrete value Ai min is found for which the least square error e becomes minimal, a post-improvement is performed. For this purpose, the values of the error square sum e are additionally considered at the neighboring points Δi min -1 and Δi m in + 1:
Aus den Werten von /, Ai, fa und der Kenntnis der Ausbreitungsgeschwindigkeit c des entsandten Signals kann dann die Entfernung d zum Ziel G berechnet werden. Der Wert Amess(Ai) in Schritt b) entspricht dabei der Zielamplitude A.From the values of /, Ai, f a and the knowledge of the propagation velocity c of the sent signal, the distance d to the target G can then be calculated. The value A mess (Ai) in step b) corresponds to the target amplitude A.
Gewerbliche Anwendbarkeit:Industrial Applicability:
Die Erfindung ist insbesondere für die Herstellung und den Betrieb von Entfernungsmessvorrichtungen, wie beispielsweise zur Abstandsregelung, zur Kollisionserkennung, zur Fahrspurerkennung oder zur allgemeinen Umfelderfassung mittels RADAR, LIDAR oder Ultraschall in Kraftfahrzeugen gewerblich anwendbar.
The invention is particularly industrially applicable to the manufacture and operation of distance measuring devices, such as for distance control, collision detection, lane detection or general environment detection by means of RADAR, LIDAR or ultrasound in motor vehicles.
Claims
1. Verfahren zur genauen Entfernungsbestimmung durch genaue1. Method for accurate distance determination by accurate
Echolaufzeitmessung eines wellenförmigen, pulsmodulierten Signals, umfassend die VerfahrensschritteEcho delay measurement of a wave-shaped, pulse-modulated signal, comprising the method steps
- Erzeugung und Entsendung des wellenförmigen, pulsmodulierten Signals,Generation and dispatch of the wave-shaped, pulse-modulated signal,
- Empfangen des von einem entfernten Gegenstand reflektierten Echos des Signals,Receiving the echo of the signal reflected from a remote object,
- Erzeugung eines Echoabtastwerte und zugeordnete, diskrete Echoabtastzeitpunkte umfassenden Echosignals durch Abtasten des empfangenen Echos mit einer endlichen Abtastrate,Generating an echo sample and associated echo signal comprising discrete echo sample times by sampling the received echo at a finite sample rate,
- Vergleich des Echosignals mit einem der Form des gesendeten Signals entsprechenden, gespeicherten Referenzsignal, wobei durch Veränderung der Referenzsignalparameter Referenzsignalamplitude und Referenzsignalphasenverschiebung diejenigen Referenzsignalparameter bestimmt werden, für die die größte Ähnlichkeit zwischen Referenzsignal und Echosignal erzielt werden, - Bestimmung der genauen Echolaufzeit anhand derComparison of the echo signal with a stored reference signal corresponding to the shape of the transmitted signal, wherein by changing the reference signal parameters reference signal amplitude and reference signal phase shift those reference signal parameters are determined for which the greatest similarity between reference signal and echo signal is obtained, determining the exact echo delay using
Referenzsignalparameter, bei denen die größte Ähnlichkeit zwischen Empfangssignal und Referenzsignal vorliegt, sowieReference signal parameters in which the greatest similarity between received signal and reference signal is present, as well as
- Bestimmung der Entfernung des Gegenstandes anhand der Ausbreitungsgeschwindigkeit und der Echolaufzeit des Signals.- Determination of the distance of the object based on the propagation speed and the echo time of the signal.
2. Verfahren nach Anspruch 1 , wobei zur Bestimmung der größten Ähnlichkeit zwischen Echosignal und Referenzsignal die Fehlerquadratsumme zwischen den beiden Signalen gebildet wird und die Referenzsignalparameter so variiert werden, dass die Fehlerquadratsumme ein Minimum einnimmt.2. The method of claim 1, wherein for determining the greatest similarity between the echo signal and the reference signal, the least square error between the two signals is formed and the reference signal parameters are varied so that the least square takes a minimum.
3. Verfahren nach Anspruch 1 oder 2, wobei das Referenzsignal in Form einer mathematischen Funktion und/oder in Form einer vorzugsweise in einer höheren Auflösung als das Empfangssignal vorliegenden Messwertfolge gespeichert ist. 3. The method of claim 1 or 2, wherein the reference signal is stored in the form of a mathematical function and / or in the form of a preferably present in a higher resolution than the received signal Meßwertfolge.
4. Verfahren nach Anspruch 1 , 2 oder 3, wobei das Echosignal zwischengespeichert wird.4. The method of claim 1, 2 or 3, wherein the echo signal is latched.
5. Verfahren nach Anspruch 4, wobei zunächst anhand des Echosignals eine Grobbestimmung der Echolaufzeit durch Bestimmung desjenigen Abtastzeitpunkts erfolgt, bei dem der zugeordnete Echoabtastwert im Vergleich zu den benachbarten Echoabtastwerten ein der Pulsmodulation entsprechendes Maximum einnimmt, und anschließend eine Feinabstimmung der Echolaufzeit durch Vergleich des zwischengespeicherten Echosignals mit dem Referenzsignal erfolgt, wobei die Referenzsignalparameter ausgehend von dem grobbestimmten Abtastzeitpunkt im Bereich der benachbarten Abtastintervalle so verändert werden, dass die größte Ähnlichkeit zwischen Referenzsignal und Echosignal erzielt wird.5. The method of claim 4, wherein first based on the echo signal, a coarse determination of the echo delay by determining that sampling time takes place in which the associated echo sample occupies a pulse modulation corresponding maximum compared to the adjacent echo samples, and then fine-tuning the echo delay by comparing the cached Echo signal with the reference signal is carried out, wherein the reference signal parameters are changed starting from the coarse sampling time in the range of the adjacent sampling intervals so that the greatest similarity between the reference signal and echo signal is achieved.
6. Verfahren nach Anspruch 5, dadurch gekennzeichnet, dass die Grobbestimmung des der Echolaufzeit entsprechenden Abtastzeitpunkts, bei dem der zugehörige Abtastwert ein Maximum einnimmt, mittels eines Matched-Filters erfolgt.6. The method according to claim 5, characterized in that the coarse determination of the echo time corresponding sampling time point at which the associated sample takes a maximum, by means of a matched filter.
7. Verfahren nach einem der vorhergehenden Ansprüche dadurch gekennzeichnet, dass das Referenzsignal durch Abtastung des gesendeten Signals mit einer endlichen Abtastrate gewonnene Signalabtastwerte sowie zugeordnete, diskrete Signalabtastzeitpunkte umfasst.A method according to any one of the preceding claims, characterized in that the reference signal comprises signal samples obtained by sampling the transmitted signal at a finite sampling rate and associated discrete signal sampling times.
8. Verfahren nach dem vorhergehenden Anspruch, dadurch gekennzeichnet, dass die Signalabtastwerte sowie die zugeordneten, diskreten Signalabtastzeitpunkte zwischengespeichert werden.8. Method according to the preceding claim, characterized in that the signal samples as well as the assigned, discrete signal sampling instants are buffered.
9. Schaltungsanordnung zur Durchführung des Verfahrens nach einem der vorhergehenden Ansprüche, gekennzeichnet durch Mittel (1 , TX) zur Erzeugung und Entsendung eines pulsmodulierten, wellenförmigen Signals, Mittel (RX) zum Empfangen eines an einem entfernten Gegenstand (G) reflektierten Echos des entsandten Signals, Mittel (3) zur Speicherung eines Referenzsignals, Mittel (5) zum Vergleich des Echosignals mit dem Referenzsignal, Mittel (5) zur Veränderung der Referenzsignalparameter, sowie Mittel (5) zur Bestimmung der Echolaufzeit sowie der Entfernung des entfernten Gegenstandes anhand der Referenzparameter Referenzsignalamplitude und Referenzsignalphasenverschiebung, bei denen die größte Ähnlichkeit zwischen Referenzsignal und Echosignal erzeugt wurde.9. Circuit arrangement for carrying out the method according to one of the preceding claims, characterized by Means (1, TX) for generating and sending a pulse modulated wave signal, means (RX) for receiving an echo of the transmitted signal reflected at a remote object (G), means (3) for storing a reference signal, means (5) for Comparison of the echo signal with the reference signal, means (5) for changing the reference signal parameters, and means (5) for determining the echo delay and the distance of the remote object based on the reference parameter reference signal amplitude and reference signal phase shift, in which the greatest similarity between the reference signal and echo signal was generated.
10. Schaltungsanordnung nach Anspruch 9, gekennzeichnet durch Mittel (3) zur Zwischenspeicherung des Echosignals.10. Circuit arrangement according to claim 9, characterized by means (3) for buffering the echo signal.
11. Schaltungsanordnung nach Anspruch 10, gekennzeichnet durch Mittel (4) zur Grobbestimmung der Echolaufzeit. 11. Circuit arrangement according to claim 10, characterized by means (4) for coarse determination of the echo delay.
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| DE200510033403 DE102005033403A1 (en) | 2005-07-18 | 2005-07-18 | Method and circuit arrangement for accurate distance determination |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101688914A (en) * | 2007-06-28 | 2010-03-31 | 罗伯特·博世有限公司 | Method and device for sensing the surroundings |
| US7974783B2 (en) | 2007-07-13 | 2011-07-05 | Dr. Ing. H.C. F. Porsche Ag | Method for determining a display image |
| EP4071586A1 (en) | 2021-04-09 | 2022-10-12 | Fresenius Medical Care Deutschland GmbH | Contactless operation of medical appliances |
| US20230379003A1 (en) * | 2020-08-05 | 2023-11-23 | Apple Inc. | Low-Frequency Detection and Ranging |
| US12039112B2 (en) | 2021-04-09 | 2024-07-16 | Fresenius Medical Care Ag | Contactless operation of devices using a pointing apparatus |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT505037B1 (en) * | 2007-05-16 | 2008-10-15 | Riegl Laser Measurement Sys | METHOD FOR DETERMINING THE TIME POSITION OF PULSES |
| DE102007045561B4 (en) | 2007-09-24 | 2018-02-15 | Robert Bosch Gmbh | Method for operating a driver assistance system |
| ATE488777T1 (en) | 2008-04-22 | 2010-12-15 | Riegl Laser Measurement Sys | DEVICE AND METHOD FOR MEASURING THE TIME OF RECEIPT OF A PULSE |
| EP2151698A1 (en) * | 2008-07-28 | 2010-02-10 | Siemens Milltronics Process Instruments Inc. | Signal processing of signals in pulse-echo measuring systems |
| AT508967B1 (en) * | 2009-10-20 | 2011-07-15 | Riegl Laser Measurement Sys | DEVICES AND METHOD FOR MEASURING THE RECEPTION TIMES OF PULSES |
| WO2011076907A1 (en) | 2009-12-22 | 2011-06-30 | Leica Geosystems Ag | Highly accurate distance measurement device |
| DE102012202975B4 (en) * | 2012-02-28 | 2024-02-08 | Robert Bosch Gmbh | Method for environmental recognition and driving assistance system |
| AT515214B1 (en) * | 2013-12-16 | 2015-07-15 | Riegl Laser Measurement Sys | Method for distance measurement |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1043602A1 (en) * | 1999-04-06 | 2000-10-11 | Leica Geosystems AG | Method for detecting the distance of at least one target |
-
2005
- 2005-07-18 DE DE200510033403 patent/DE102005033403A1/en not_active Withdrawn
-
2006
- 2006-05-31 WO PCT/EP2006/062794 patent/WO2007009833A1/en active Application Filing
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1043602A1 (en) * | 1999-04-06 | 2000-10-11 | Leica Geosystems AG | Method for detecting the distance of at least one target |
Non-Patent Citations (4)
| Title |
|---|
| HAJJARI A ET AL: "A D-RLS method for estimating an exponentially complex signal with application to scattering centers identification", OCEANS '99 MTS/IEEE. RIDING THE CREST INTO THE 21ST CENTURY SEATTLE, WA, USA 13-16 SEPT. 1999, PISCATAWAY, NJ, USA & WASHINGTON, DC, US, US, vol. 1, 13 September 1999 (1999-09-13), pages 305 - 309, XP010354774, ISBN: 0-7803-5628-4 * |
| KARASALO I ET AL: "Object identification by bistatic acoustic scattering", OCEANS 2005 - EUROPE (IEEE CAT. NO. 05EX1042) IEEE PISCATAWAY, NJ, USA, vol. 1, 20 June 2005 (2005-06-20) - 23 June 2005 (2005-06-23), pages 495 - 500, XP002393668, ISBN: 0-7803-9103-9 * |
| OLIVIER BESSON ET AL: "Parameter Estimation for Random Amplitude Chirp Signals", IEEE TRANSACTIONS ON SIGNAL PROCESSING, IEEE SERVICE CENTER, NEW YORK, NY, US, vol. 47, no. 12, December 1999 (1999-12-01), XP011058779, ISSN: 1053-587X * |
| VAN DE BEEK, JAN-JAAP; BÖRJESSON, PER-OLA; ERIKSSON, HÅKAN; GUSTAVSSON, JAN-OLOF; OLSSON, LENNAR: "MMSE Estimation of Arrival Time with Application to Ultrasonic Signals", RESEARCH REPORT, 5 April 1993 (1993-04-05), XP002393669, ISSN: 0347-0881, Retrieved from the Internet <URL:http://epubl.luth.se/avslutade/0347-0881/93-15/bbe93r.pdf> [retrieved on 20060803] * |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101688914A (en) * | 2007-06-28 | 2010-03-31 | 罗伯特·博世有限公司 | Method and device for sensing the surroundings |
| US8363511B2 (en) | 2007-06-28 | 2013-01-29 | Robert Bosch Gmbh | Method and device for detection of surroundings |
| US7974783B2 (en) | 2007-07-13 | 2011-07-05 | Dr. Ing. H.C. F. Porsche Ag | Method for determining a display image |
| US20230379003A1 (en) * | 2020-08-05 | 2023-11-23 | Apple Inc. | Low-Frequency Detection and Ranging |
| EP4071586A1 (en) | 2021-04-09 | 2022-10-12 | Fresenius Medical Care Deutschland GmbH | Contactless operation of medical appliances |
| WO2022214673A2 (en) | 2021-04-09 | 2022-10-13 | Fresenius Medical Care Deutschland Gmbh | Contactless operation of medical devices |
| US11693489B2 (en) | 2021-04-09 | 2023-07-04 | Fresenius Medical Care Deutschland Gmbh | Contactless operation of medical devices using a pointing apparatus |
| US12039112B2 (en) | 2021-04-09 | 2024-07-16 | Fresenius Medical Care Ag | Contactless operation of devices using a pointing apparatus |
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