DE10350746A1 - Method for localizing position of object e.g. for domestic robots, uses signal propagation time differences to determine position of object - Google Patents

Abstract

A method for determining a position of an object, in which time relation of a signal propagation times between at least three reference units of exchanged signals is determined and in which a signal is sent from the objects to the reference units and the signal propagation time differences are formed, which describe the differences of the respective signal propagation times of the signals sent from the objects to the reference units, and in which by using the signal propagation time difference, a time relation of the signal propagation times and the position of the objects is determined by taking into account the position of the reference units. An independent claim is included for a system for determining the position of an object.

Description

The The invention relates to a system and method for locating an object, and in particular a system for locating a Object and an associated one Method, wherein the position of an object can be located without doing a synchronization of clocks in the object and in needed for localization Reference units are provided.

A common one Method for the absolute two-dimensional localization of objects and persons is the so-called triangulation, also referred to as Trilateration as described in [2]. This will be wireless between installed in the object to be located and in the environment Reference Units Signal propagation times of signals determined between be exchanged to the object to be located and the reference units. These signal delays can converted into distances with the aid of the propagation velocity of the signals become. For Each reference unit is the mobile after a transit time measurement Object on an imaginary circle with the radius of the corresponding Distance. If three such circles are cut, then this yields the desired location of the mobile object.

to Runtime measurement - too referred to as "Time of Flight Measurement "- of electromagnetic or acoustic signals between two objects of a positioning system is usually a synchronization of the clocks of these objects required. This is especially with very small signal propagation times, as they are in the transfer from electromagnetic waves occur, problematic as a high accuracy of synchronization would be necessary.

at Existing systems often solve this problem by: the participants over Radio transceiver for synchronization and ultrasonic transducer for the Have signal transit time measurement, as described in [4]. A reference unit sends in at the same time Radio signal and an ultrasonic signal to the mobile object. At the Receiving the radio signal becomes the internal clock of the mobile object reset. Because the electromagnetic signal is much faster than that Acoustic signal propagates falls only the signal delay of the acoustic signal in the weight. The clock of the mobile object will therefore only measure the time that the Sound from the reference unit to the object has needed. Subsequently, will repeats the procedure with the other reference units and the Position of the object determined by triangulation. The disadvantages this procedure are that for the reference units both ultrasonic transceiver and radio transceiver needed become. Furthermore, a sequence of measurements is required while the the mobile object is not allowed to change its position significantly.

The satellite-based Navigation system GPS (Global Positioning System) allows one worldwide satellite-based Localization as described in [3]. The satellites are with atomic clocks equipped and send in a certain time frame radio signals off, which with a timestamp to synchronize the clocks the satellites of the clock of an object are provided. With a GPS receiver can the radio signals are detected and evaluated by triangulation.

In an alternative approach of signal transit time determination is the Synchronization of the clocks avoided. In this approach of signal transit time determination a signal is emitted by a first participant and the time measured until active or passive from one in the reception area the first participant located, second participant reflected signal arrives again, as described in [1]. Again, there is a sequence required by measurements. In addition, active reflection will be for everyone Subscriber both a transmitting unit and a receiving unit needed. Passive reflection, however, is not very practical because the participants can not be identified. Furthermore, the reflected signal due to the scattering has a low Level and is possibly very noisy, causing errors in the signal detection can occur and thus the reliability and the accuracy of the position determination for a subscriber reduced is.

Of the The invention is based on the problem, a system and an associated method to locate an object, the position of the Object can be determined without doing a synchronization of Having to make clocks the reference units needed in the object and for localization provided are.

The Problem is solved by a method and a system for determining a Position of an object with the features solved according to the independent claims.

According to the method of the invention to determine a position of an object becomes a temporal relation, preferably the time interval, of signal transit times between between at least three reference units exchanged signals determined; the object sends a signal to the reference units Posted; Signal propagation time differences are formed, which are the Differences of the respective signal propagation times of the object sent by the object Describe signal to the reference units; and is being used the signal propagation time differences, the temporal relation of signal propagation times as well as considering the Positions of the reference units determines the position of the object.

One inventive system for determining a position of an object comprises: at least three reference units which are arranged to send and for receiving signals; and means for determining a temporal relation, preferably the time interval, of signal propagation times between signals exchanged between the reference units; and an object configured to transmit a signal the reference units; and means for determining signal propagation time differences, which the differences of the respective signal delays of the Describe object sent signal to the reference units; and means for determining the position of the object below Use of the signal propagation time differences, the temporal relation of signal transit times and taking into account the positions the reference units.

With other words each of the at least three reference units both via a Transmitting unit as well over a receiving unit. The transmitting unit and the receiving unit can, for example, by means of be realized a transceiver.

clear is due to the invention the use of signal delay differences instead of signal delays as per the stand the technique in the context of determining the object position achieved that a synchronization of the clocks in the object and in the localization required Reference units are provided, is no longer necessary.

Further is inventively also in the object to be located does not require a receiver, whereby the system and In particular, the design of the object considerably simplified and cheaper can be designed.

In addition, according to the invention control commands and transmit measurement data of the localization system via the same transmitting and receiving device be with which the signal delay signals are detected, which the system can be realized even easier and cheaper.

preferred Embodiments of the invention will become apparent from the dependent claims. The Embodiments described below relate to the method and the system for determining the position of an object.

Prefers is that the reference units and the object each have the same speed have running clocks.

In In this context, it should be noted that the watches Although they run at the same speed, they do not need to be synchronized.

Prefers Electromagnetic signals are used as signals whose propagation speed in air the speed of light is.

Prefers is further determined that the time interval of the signal propagation times is performed by performing at least two reference measurements, wherein in a first reference measurement, a first of the at least three Reference units a first reference signal to the other reference units sends, wherein in a second reference measurement, a second of at least three reference units a second reference signal to the other Referencing units sends, where in both reference measurements respectively the reference signal reception times are detected, and wherein considering the position of the reference units, the respective reference signal transit times be determined.

Consequently is due to the use of signal propagation time differences of signal transit times as in the state the technique achieved in the context of the determination of the object position, that is a synchronization of the clocks in the object and in the localization required Reference units are provided, is no longer necessary.

• • t_ab eine Signallaufzeit zwischen einer Referenzeinheit a und einer Referenzeinheit b,
• • t_s,b ein lokaler Signalsendezeitpunkt an der Referenzeinheit b,
• • Δt_b ein Uhrenversatz zwischen einer lokalen Uhrzeit der Referenzeinheit b und einer fiktiven globalen Uhrzeit,
• • t_r,ba ein lokaler Signalempfangszeitpunkt in der Referenzeinheit a für ein von der Referenzeinheit b zur Referenzeinheit a gesendetes Signal,
• • Δt_a ein Uhrenversatz zwischen einer lokalen Uhrzeit der Referenzeinheit a und der fiktiven globalen Uhrzeit,
• • t_bc eine Signallaufzeit zwischen der Referenzeinheit b und einer Referenzeinheit c,
• • t_r,bc ein lokaler Signalempfangszeitpunkt in der Referenzeinheit c für ein von der Referenzeinheit b zur Referenzeinheit c gesendetes Signal, und
• • Δt_c ein Uhrenversatz zwischen einer lokalen Uhrzeit der Referenzeinheit c und der fiktiven globalen Uhrzeit

bezeichnet wird,
wobei unter Berücksichtigung der zweiten Referenzmessung folgende Vorschriften verwendet werden: tac + ts,c + Δtc = tr,ca + Δta tbc + ts,c + Δtc = tr,cb + Δtb Δta – Δtb = tac – tbc – tr,ca + tr,cb,wobei mit

• • t_ac eine Signallaufzeit zwischen der Referenzeinheit a und der Referenzeinheit c,
• • t_s,c ein lokaler Signalsendezeitpunkt an der Referenzeinheit c,
• • t_r,ca ein lokaler Signalempfangszeitpunkt in der Referenzeinheit a für ein von der Referenzeinheit c zur Referenzeinheit a gesendetes Signal, und
• • t_r,cb ein lokaler Signalempfangszeitpunkt in der Referenzeinheit b für ein von der Referenzeinheit c zur Referenzeinheit b gesendetes Signal bezeichnet wird.

Furthermore, it is preferred that the temporal relation of the signal propagation times is determined using the following rules, wherein, taking into account the first reference measurement, the following rules are used: t from + t s, b + Δt b = t r, ba + Δt a . t bc + t s, b + Δt b = t r, bc + Δt c . .delta.t a - Δt c = t from - t bc - t r, ba + t r, bc . being with

• T _from a signal delay between a reference unit a and a reference unit b,
• T _{s, b is} a local signal transmission time at the reference unit b,
• Δt _{b is} a clock offset between a local time of the reference unit b and a fictitious global time,
• T _{r, ba is} a local signal reception time in the reference unit a for a signal sent from the reference unit b to the reference unit a,
• Δt _{a is} a clock offset between a local time of the reference unit a and the fictitious global time,
• T _bc a signal transit time between the reference unit b and a reference unit c,
• T _{r, bc is} a local signal reception time in the reference unit c for a signal sent from the reference unit b to the reference unit c, and
• Δt _{c is} a clock offset between a local time of the reference unit c and the fictitious global time

referred to as,
taking into account the second reference measurement, the following rules are used: t ac + t s, c + Δt c = t r, ca + Δt a t bc + t s, c + Δt c = t r, cb + Δt b .delta.t a - Δt b = t ac - t bc - t r, ca + t r, cb . being with

• T _ac a signal transit time between the reference unit a and the reference unit c,
• T _{s, c is} a local signal transmission time at the reference unit c,
• T _{r, ca} a local signal reception time in the reference unit a for a signal sent from the reference unit c to the reference unit a, and
• T _{r, cb denotes} a local signal reception time in the reference unit b for a signal sent from the reference unit c to the reference unit b.

According to one Embodiment of the invention, the signal propagation time differences of the signal sent from the object to the reference units Use of the reference signal reception times and the reference signal transit times formed. Further, to determine the position of the object, running path differences the signal sent from the object to the reference units.

• • d₁ ein zwischen den Referenzeinheiten a und b vorhandener Laufwegeunterschied des vom Objekt an die Referenzeinheiten gesendeten Signals,
• • d₂ ein zwischen den Referenzeinheiten a und c vorhandener Laufwegeunterschied des vom Objekt an die Referenzeinheiten gesendeten Signals,
• • t_r,ma ein lokaler Signalempfangszeitpunkt in der Referenzeinheit a für das vom Objekt an die Referenzeinheiten gesendete Signal,
• • t_r,mb ein lokaler Signalempfangszeitpunkt in der Referenzeinheit b für das vom Objekt an die Referenzeinheiten gesendete Signal, und
• • t_r,mc ein lokaler Signalempfangszeitpunkt in der Referenzeinheit c für das vom Objekt an die Referenzeinheiten gesendete Signal bezeichnet wird.

Preferably, the differences in running distances are determined using the following rules: d 1 = (t r, ma - t r, mb + t ac - t bc - t r, ca + t r, cb ) · V p d 2 = (t r, ma - t r, mc + t from - t bc - t r, ba + t r, bc ) · V p being with

• D _{1 is} a path difference between the reference units a and b of the signal sent by the object to the reference units,
• D _{2 is} a running-path difference between the reference units a and c of the signal sent by the object to the reference units,
• T _{r, ma is} a local signal reception time in the reference unit a for the signal sent from the object to the reference units,
• T _{r, mb is} a local signal reception time in the reference unit b for the signal sent by the object to the reference units, and
• T _{r, mc is} a local signal reception time in the reference unit c for the signal sent from the object to the reference units.

und

wobei mit

• • x_a eine erste Teil-Positionsangabe der Referenzeinheit a bezogen auf eine erste Koordinatenrichtung,
• • y_a eine zweite Teil-Positionsangabe der Referenzeinheit a bezogen auf eine zweite Koordinatenrichtung,
• • x_b eine erste Teil-Positionsangabe der Referenzeinheit b bezogen auf die erste Koordinatenrichtung,
• • y_b eine zweite Teil-Positionsangabe der Referenzeinheit b bezogen auf die zweite Koordinatenrichtung,
• • x_c eine erste Teil-Positionsangabe der Referenzeinheit c bezogen auf die erste Koordinatenrichtung,
• • y_c eine zweite Teil-Positionsangabe der Referenzeinheit c bezogen auf die zweite Koordinatenrichtung,
• • x_m eine erste Teil-Positionsangabe des Objekts bezogen auf die erste Koordinatenrichtung, und
• • y_m eine zweite Teil-Positionsangabe des Objekts bezogen auf die zweite Koordinatenrichtung bezeichnet wird.

Furthermore, the position of the object is preferably determined according to the following rules: x m = c 1 · y m + c 2 . With

and

being with

• X _{a is} a first partial position specification of the reference unit a with respect to a first coordinate direction,
• Y _a a second partial position specification of the reference unit a with respect to a second coordinate direction,
• X _b a first partial position specification of the reference unit b with respect to the first coordinate direction,
• Y _{b is} a second partial position specification of the reference unit b with respect to the second coordinate direction,
• X _{c is} a first partial position specification of the reference unit c with respect to the first coordinate direction,
• Y _c a second partial position specification of the reference unit c with respect to the second coordinate direction,
• X _{m is} a first partial position specification of the object relative to the first coordinate direction, and
• • y _{m is} a second partial position information of the object referred to the second coordinate direction.

Due to the quadratic relationship given above, there are two potential positions for the object, namely x _m1 , y _m1 and x _m2 , y _m2 .

According to the invention, the correct position can be determined unambiguously by calculating the path differences d ₁ , d ₂ (delta distances ₎ for both positions using the following instructions and then comparing them with the given value pair d ₁ , d ₂ :

If the given value pair d ₁ , d ₂ coincides with the value pair d ₁ , d ₂ that has been recalculated, the correct position indication is determined.

There may also be positions for which the opposite calculation supplies the same recalculated value pair d ₁ , d ₂ in both cases. In such a case, the correct position indication can be selected by a plausibility analysis from the two possible position information.

Prefers the position of the object in the object is determined.

Further it is preferred that an autonomous system be used as the object, which depends on the determined position is controlled.

The For example, a home robot (e.g., an autonomous Vacuum cleaner robot or the like), an industrial robot, e.g. parts transported from one machine to another machine, or a Personal Digital Assistant (PDA) with the help of which Users can navigate.

Besides that is preferred that the inventive method in one of the following Areas: robot localization, warehouse automation, In-house localization, Warehouse tracking or e-commerce.

For example can in the field of robot localization, the inventive method and system are used to determine the position of a home robot, such as an autonomous vacuum cleaner robot, or the Position of an industrial robot to determine, for example used to transport parts to navigate to enable the robot.

in the Use case of in-house localization, for example, the Position of a searched object, such as a particular one Products in a department store or a car key or a mobile phone, in a living room, to be determined.

One Another example is the position determination of a person who an object with at least one transmitting unit carries with it. The The object can be, for example, a PDA with a radio transmission unit. a mobile phone or a separate mini-radio transmitter. With the position determination the person can the person, for example, in an exhibition or in a department store, targeted by a central computer information transmitted such as historical information about each Exhibits of the exhibition or additional information about a particular Goods in the department store. The information is output via loudspeakers, for example or over a screen.

Prefers the object has a receiver for receiving a signal.

Thus, the data necessary for determining the position of an object can be received by the object so that the determination of the position of the object or the determination of the position of the object relative to a search object in the object can be performed.

According to one Another embodiment of the invention, the reference units and the object each equally fast running clocks on.

embodiments The invention is illustrated in the figures and will be described below explained in more detail. The Invention can be used in software, i. by means of a computer program, in hardware, i. by means of a special electronic circuit, or in any hybrid form, i. in any combination in Software and hardware, be realized.

It demonstrate:

1 a representation of the geometric relationship in the localization of an object that is exploited in the context of the method and the system according to the invention;

2 a first embodiment of the system according to the invention;

3 a second embodiment of the system according to the invention.

First embodiment

The following is with reference to 1 and 2 a first embodiment of the invention described.

According to the first embodiment, at least three reference units, and as in 2 3, three reference units a, b, c are provided, which are set up for transmitting and receiving radio signals. In other words, each reference unit a, b, c has both a radio transmitting unit and a radio receiving unit, which are arranged according to the embodiments according to the Bluetooth standard. The radio transmission unit and the radio reception unit can be realized, for example, by means of a transceiver.

The three reference units a, b, c are installed in a living space W with their respective positions (x _a , y _a ); ( _xb , _yb ); (x _c , y _c ) (see 1 ) are known as position information relative to a first and a second, to the first orthogonal coordinate direction in a given Cartesian coordinate system.

Furthermore, an object m is provided, which is set up for transmitting a radio signal to the reference units a, b, c. In other words, the object m has at least one radio transmission unit, however, as in this embodiment, it may additionally have a radio reception unit. The object m is also located in the living space W at a current position (x _m , y _m ) (see 1 ) as position information of the object m with respect to the first and second coordinate directions.

In addition, sensors can S be provided for detecting parameters, such as the Temperature, humidity or other physical parameters.

These Sensors S can for example, separately in the living room W or in the reference units a, b, c are installed.

at this embodiment the sensors S are installed in the reference units a, b, c.

Further, in this embodiment of the invention, the object m is an autonomous vacuum cleaner robot 1 which is arranged for independent orientation and movement within one of the vacuum cleaner robot 1 to be cleaned environment. The vacuum cleaner robot 1 has a suction unit 15 , a drive unit 12 , a radio receiving unit 13 , a radio transmission unit 14 and a microprocessor 11 on, who can control the individual vacuum cleaner components.

To perform the cleaning it is for the vacuum cleaner robot 1 It is necessary for him to be able to orientate himself in the environment, which in turn presupposes that he can determine his own position within the environment in order to depend on, for example, one stored in his memory th route to calculate its direction of movement and movement speed.

The sensors S provided in the reference units a, b, c may further be the vacuum cleaner robot 1 Provide information that he needs to complete his task. In this embodiment, the sensors S are, for example, sensors for detecting obstacles contained in the environment to be cleaned and thus the vacuum cleaner robot 1 on its previously stored route, where the obstacle is not yet taken into account, are in the way.

Additionally or alternatively, the vacuum cleaner robot 1 Motion sensors (not shown), which is a abutment of the vacuum cleaner robot 1 on other objects, such as tables and chairs, or the new ones described above, that are added after creating and saving the route map, prevent.

In this embodiment, the radio signals from the reference units a, b, c and the vacuum cleaner robot, respectively 1 be emitted, radio signals whose propagation velocity v _{p is} known, such as for a radio signal in air, the speed of light.

The vacuum cleaner robot 1 and the three reference units a, b, c are also referred to below as participants.

All Participants have equally fast running clocks that are not synchronized have to be i.e. the current local time of one participant is the other Participants not known.

By means of the vacuum cleaner robot 1 provided microprocessor 11 the devices described below are implemented in the form of a computer program which, when executed, has the method steps described in the following method.

The vacuum cleaner robot 1 is provided with a first device for determining a temporal relation, preferably the distance, of signal propagation times between signals exchanged between the reference units a, b, c. However, the first device can also be provided in one of the reference units a, b, c.

Further, the vacuum cleaner robot 1 with a second device for determining signal propagation time differences, which are the differences of the respective signal propagation times of the vacuum cleaner robot 1 transmitted signal to the reference units a, b, c describe. This second device can, if desired, also be arranged in one of the reference units a, b, c.

In addition, the vacuum cleaner robot 1 provided with a third means for detecting the position of the vacuum cleaner robot 1 using the signal propagation time differences, the temporal relation of signal propagation times and taking into account the positions x _a , y _a ; _xb , _yb ; x _c , y _{c of} the reference units a, b, c.

It It should be noted in this connection that the institution is in one alternative embodiment of the invention according to all embodiments in a separate Unit, which has a suitably programmed microprocessor has, can be realized.

Now will be detailed and with reference to 1 and 2 the process of locating the vacuum cleaner robot 1 described.

The autonomous vacuum cleaner robot 1 can move freely in the living room W and cleans, depending on the default by a user, the living room W automatically. The vacuum cleaner robot receives this 1 from the sensors S information about obstacles, so as to adapt the stored and thus preset route, if necessary, depending on the existence of new obstacles on the preset route.

To allow the vacuum cleaner robot 1 the room to be cleaned can find and in this room the predetermined cleaning route can depart, the current position (x _m , y _m ) (see 1 ) of the vacuum cleaner robot 1 determined.

Before the vacuum cleaner robot 1 can be localized, it is necessary to determine a temporal relation of signal transit times between signals exchanged between the reference units a, b, c. With In other words, a temporal relationship between the reference units a, b, c is made, taking their geometric arrangement is used. This is done by means of two reference measurements which will be described in more detail below.

For the actual position determination of the vacuum cleaner robot 1 is only a single measurement required, the exact communication process and the control process of the individual participants for reasons of clarity of the presentation of the invention will not be described in detail. At the beginning of the localization process, the vacuum cleaner robot sends 1 via its radio transmission unit 14 a localization radio signal received from the reference units a, b, c. From the local receiving times, the transit time differences and thus running distances differences (delta distances) of the localization radio signal to the individual reference units a, b, c can then be determined.

• • l_pq: räumlich kürzeste Entfernung zwischen Teilnehmern p und q;
• • t_pq: Funksignallaufzeit zwischen Teilnehmern p und q;
• • t_p: Lokale Uhrzeit von Teilnehmer p;
• • Δt_p: Uhrenversatz zwischen globaler Uhrzeit und lokaler Uhrzeit in Teilnehmer p;
• • t_s,p: Lokaler Signalsendezeitpunkt in Teilnehmer p;
• • t_r,pq: Lokaler Signalempfangszeitpunkt in Teilnehmer q für ein von Teilnehmer p an den Teilnehmer q gesendetes Funksignal.

Before further explanation, some quantities are first introduced, where p, q ∈ {a, b, c, m}

• • l _pq : spatially shortest distance between participants p and q;
• • t _pq : radio signal transit time between subscribers p and q;
• • t _p : local time of subscriber p;
• • Δt _p : clock offset between global time and local time in subscriber p;
• T _{s, p} : local signal transmission time in subscriber p;
• • t _{r, pq} : local signal reception time in subscriber q for a radio signal transmitted by subscriber p to subscriber q.

The local times t _a , t _b , t _c , t _{m of} the individual subscribers are set via offsets in relation to a fictitious global time t _g , resulting in the following rule; t G = t a + Δt a = t b + Δt b = t c + Δt c = t m + Δt m , (1)

wobei mit

• • t_am eine Signallaufzeit zwischen der Referenzeinheit a und dem Staubsauger-Roboter 1 (Objekt m),
• • t_bm eine Signallaufzeit zwischen der Referenzeinheit b und dem Staubsauger-Roboter 1,
• • t_cm eine Signallaufzeit zwischen der Referenzeinheit c und dem Staubsauger-Roboter 1,
• t_ab eine Signallaufzeit zwischen der Referenzeinheit a und der Referenzeinheit b,
• • t_ac eine Signallaufzeit zwischen der Referenzeinheit a und der Referenzeinheit c, und
• • t_bc eine Signallaufzeit zwischen der Referenzeinheit b und der Referenzeinheit c bezeichnet wird.

The signal transit times between the individual subscribers can be determined by the following rules:

being with

• T _on a signal transit time between the reference unit a and the vacuum cleaner robot 1 (Object m),
• T _bm a signal _transit time between the reference unit b and the vacuum cleaner robot 1 .
• T _{cm is} a signal transit time between the reference unit c and the vacuum cleaner robot 1 .
• t _ab a signal delay between the reference unit a and the reference unit b,
• T _ac a signal transit time between the reference unit a and the reference unit c, and
• • t _bc a signal delay between the reference unit b and the reference unit c is called.

in the The following describes the three measurements that are required for localization carried out are, i. the actual localization measurement as well as the two already mentioned Reference measurements.

In order to eliminate the relations (offsets) of the reference units Δt _a , Δt _b , Δt _c to the global time t _g , two reference measurements are performed. In this case, the second reference unit b transmits via its radio transmission unit a first reference radio signal which is received by the first reference unit a and the third reference unit c by means of their respective radio reception units.

In the second reference measurement sends the third reference unit c on their Radio transmission unit, a second reference radio signal, which of the first reference unit a and the second reference unit b by means of their respective radio receiving units is received.

With the help of in 1 The geometric relationships shown, the local times of the reference units a, b, c are synchronized with each other implicitly.

In other words, in the first reference measurement, the second reference unit b of the three reference units a, b, c transmits a first reference radio signal to the other reference units a and c. In the second reference measurement, the third reference unit c of the three reference units a, b, c sends a second reference radio signal to the other reference units a and b. In both reference measurements, the reference radio signal reception times of the respective radio signal are respectively detected in the reference unit receiving this radio signal. Taking into account the known positions of the reference units a, b, c (x _a , y _a ), (x _b , y _b ), (x _c , y _c ), the respective reference signal transit times are determined.

• • t_ab die Signallaufzeit zwischen der Referenzeinheit a und der Referenzeinheit b,
• • t_s,b ein lokaler Signalsendezeitpunkt an der Referenzeinheit b,
• • Δt_b ein Uhrenversatz zwischen einer lokalen Uhrzeit der Referenzeinheit b und der fiktiven globalen Uhrzeit t_g,
• • t_r,ba ein lokaler Signalempfangszeitpunkt in der Referenzeinheit a für ein von der Referenzeinheit b zur Referenzeinheit a gesendetes Signal,
• • Δt_a ein Uhrenversatz zwischen der lokalen Uhrzeit der Referenzeinheit a und der fiktiven globalen Uhrzeit t_g,
• • t_bc die Signallaufzeit zwischen der Referenzeinheit b und der Referenzeinheit c,
• • t_r,bc ein lokaler Signalempfangszeitpunkt in der Referenzeinheit c für ein von der Referenzeinheit b zur Referenzeinheit c gesendetes Signal, und
• • Δt_c ein Uhrenversatz zwischen einer lokalen Uhrzeit der Referenzeinheit c und der fiktiven globalen Uhrzeit t_g bezeichnet wird.

In a next step, the temporal relation of the reference signal transit times is determined, whereby the following rules are used taking into account the first reference measurement: t from + t s, b + Δt b = t r, ba + Δt a , (8th) t bc + t s, b + Δt b = t r, bc + Δt c , (9) .delta.t a - Δt c = t from - t bc - t r, ba + t r, bc , (10) being with

• T _from the signal transit time between the reference unit a and the reference unit b,
• T _{s, b is} a local signal transmission time at the reference unit b,
• Δt _{b is} a clock offset between a local time of the reference unit b and the fictitious global time t _g ,
• T _{r, ba is} a local signal reception time in the reference unit a for a signal sent from the reference unit b to the reference unit a,
• Δt _{a is} a clock offset between the local time of the reference unit a and the fictitious global time t _g ,
• T _bc the signal transit time between the reference unit b and the reference unit c,
• T _{r, bc is} a local signal reception time in the reference unit c for a signal sent from the reference unit b to the reference unit c, and
• Δt _{c is} a clock offset between a local time of the reference unit c and the fictitious global time t _g is called.

• • t_ac die Signallaufzeit zwischen der Referenzeinheit a und der Referenzeinheit c,
• • t_s,c ein lokaler Signalsendezeitpunkt an der Referenzeinheit c,
• • t_r,_ca ein lokaler Signalempfangszeitpunkt in der Referenzeinheit a für ein von der Referenzeinheit c zur Referenzeinheit a gesendetes Signal, und
• • t_r,_cb ein lokaler Signalempfangszeitpunkt in der Referenzeinheit b für ein von der Referenzeinheit c zur Referenzeinheit b gesendetes Signal bezeichnet wird.

Taking into account the second reference measurement, the following rules are used: t ac + t s, c + Δt c = t r, ca + Δt a , (11) t bc + t s, c + Δt c = t r, cb + Δt b , (12) .delta.t a - Δt b = t ac - t bc - t r, ca + t r, cb , (13) being with

• T _ac the signal transit time between the reference unit a and the reference unit c,
• T _{s, c is} a local signal transmission time at the reference unit c,
• T _r , _ca a local signal reception time in the reference unit a for a signal sent from the reference unit c to the reference unit a, and
• T _r , _{cb denotes} a local signal reception time in the reference unit b for a signal sent from the reference unit c to the reference unit b.

The reference signal transit times t _ab , t _ac , t _bc can be determined from the geometric arrangement of the reference units a, b, c (see 1 ). The variables t _{r, ba} , t _{r, bc} t _{r, ca} , t _r , _cb result from the two reference measurements and may need to be determined only once. Depending on the requirement, however, the two reference measurements can be repeated at certain time intervals in order to compensate for a drifting apart of the clocks of the reference units a, b, c.

In a next step, the signal propagation time differences of the vacuum cleaner robot 1 formed on the reference units a, b, c transmitted localization radio signal using the reference signal reception times and the reference signal transit times. The vacuum cleaner robot 1 sends the localization radio signal to its local time t _{s, m} . The location radio signal is received by the reference units a, b, c at their respective local time t _{r, ma} , t _{r, mb} , t _{r, mc} . Taking into account the individual clock offsets Δt _a , Δt _b , Δt _{c of} the reference units a, b, c at the global time t _g (which need not be known) Receiving units per subscriber here are assumed to be constant and are implicitly contained in the clock offset: t at the + t s, m + Δt m = t r, ma + Δt a , (14) t bm + t s, m + Δt m = t r, mb + Δt b , (15) t cm + t s, m + Δt m = t r, mc + Δt c , (16)

• • d₁ ein zwischen den Referenzeinheiten a und b vorhandener Laufwegeunterschied des vom Staubsauger-Roboter 1 (Objekt m) an die Referenzeinheiten gesendeten Signals,
• • d₂ ein zwischen den Referenzeinheiten a und c vorhandener Laufwegeunterschied des vom Staubsauger-Roboter 1 an die Referenzeinheiten gesendeten Signals,
• • Δt_m der Uhrenversatz zwischen der lokalen Uhrzeit des Staubsauger-Roboters 1 (Objekt m) und der fiktiven globalen Uhrzeit t_g,
• • Δt_a der Uhrenversatz zwischen der lokalen Uhrzeit der Referenzeinheit a und der fiktiven globalen Uhrzeit t_g,
• • Δt_b der Uhrenversatz zwischen der lokalen Uhrzeit der Referenzeinheit b und der fiktiven globalen Uhrzeit t_g,
• • Δt_c der Uhrenversatz zwischen der lokalen Uhrzeit der Referenzeinheit c und der fiktiven globalen Uhrzeit t_g,
• • t_am die Signallaufzeit zwischen der Referenzeinheit a und dem Staubsauger-Roboter 1 (Objekt m),
• • t_bm die Signallaufzeit zwischen der Referenzeinheit b und dem Staubsauger-Roboter 1,
• • t_cm die Signallaufzeit zwischen der Referenzeinheit c und dem Staubsauger-Roboter 1,
• • t_r,_ma ein lokaler Signalempfangszeitpunkt in der Referenzeinheit a für das vom Staubsauger-Roboter 1 an die Referenzeinheiten gesendete Signal,
• • t_r,mb ein lokaler Signalempfangszeitpunkt in der Referenzeinheit b für das vom Staubsauger-Roboter 1 an die Referenzeinheiten gesendete Signal,
• • t_r,_mc ein lokaler Signalempfangszeitpunkt in der Referenzeinheit c für das vom Staubsauger-Roboter 1 an die Referenzeinheiten gesendete Signal, und
• • t_s,m ein lokaler Signalsendezeitpunkt im Staubsauger-Roboter 1 bezeichnet wird.

Further, to determine the position of the vacuum cleaner robot 1 Runway differences d ₁ , d ₂ (delta distances) of the vacuum cleaner robot 1 taken into account for the localization radio signal transmitted to the reference units a, b, c, wherein the path differences d ₁ , d ₂ are determined using the following rules: d 1 = (t at the - t bm ) · V p = (t r, ma + Δt a - t r, mb - Δt b ) · V p , (17) d 2 = (t at the - t cm ) · V p - (t r, ma + Δt a - t r, mc - Δt c ) · V p , (18) being with

• D _{1 is} a difference in running distance between the reference units a and b and that of the vacuum cleaner robot 1 (Object m) signal sent to the reference units,
• D _{2 is} a difference in running distance between the reference units a and c and that of the vacuum cleaner robot 1 signal sent to the reference units,
• • Δt _{m is} the clock offset between the local time of the vacuum cleaner robot 1 (Object m) and the fictitious global time t _g ,
• Δt _{a is} the clock offset between the local time of the reference unit a and the fictitious global time t _g ,
• Δt _{b is} the clock offset between the local time of the reference unit b and the fictitious global time t _g ,
• Δt _{c is} the clock offset between the local time of the reference unit c and the fictitious global time t _g ,
• • t _am the signal transit time between the reference unit a and the vacuum cleaner robot 1 (Object m),
• T _bm the signal _transit time between the reference unit b and the vacuum cleaner robot 1 .
• • t _{cm is} the signal transit time between the reference unit c and the vacuum cleaner robot 1 .
• T _r , _{ma is} a local signal reception time in the reference unit a for that of the vacuum cleaner robot 1 signal sent to the reference units,
• T _{r, mb is} a local signal reception time in the reference unit b for that of the vacuum cleaner robot 1 signal sent to the reference units,
• T _r , _{mc is} a local signal reception time in the reference unit c for the vacuum cleaner robot 1 signal sent to the reference units, and
• T _{s, m is} a local signal transmission time in the vacuum cleaner robot 1 referred to as.

Is the provision ( 13 ) in the regulation ( 17 ), Where the term .DELTA.t _a - _b .DELTA.t in procedure ( 17 ) by the provision ( 13 ), the following provision can be made: d 1 = (t r, ma - t r, mb + t ac - t bc - t r, ca + t r, cb ) · V p (19)

Is the provision ( 10 ) in the regulation ( 18 ), Where the term .DELTA.t _a - _c .DELTA.t in procedure ( 18 ) by the provision ( 10 ), the following provision can be made: d 2 = (t r, ma - t r, mc + t from - t bc - t r, ba + t r, bc ) · V p (20)

After the running-path differences d ₁ , d ₂ (delta distances) have been determined, the current position (x _m , y _m ) of the vacuum cleaner robot can now be determined 1 be determined. In doing so, the following rules are used, which are derived from those in 1 shown geometric relationships result in: d 1 = l at the - l bm , (21) d 2 = l at the - l cm , (22) With (x m - x a ) 2 + (y m - y a ) 2 = l 2 at the , (23) (x m - x b ) 2 + (y m - y b ) 2 = l 2 bm , (24) (x m - x c ) 2 + (y m - y c ) 2 = l 2 cm , (25) (x m - x ' b ) 2 + (y m - y ' b ) 2 = l 2 bm , (26) (x m - x ' b ) 2 + (y m - y ' b ) 2 = l 2 bm , (27) (x ' b - x a ) 2 + (y ' b - y a ) 2 = d 2 1 , (28) and (x ' c - x a ) 2 + (y ' c - y a ) 2 = d 2 2 , (29) With

wobei x_a, y_a, x_b, y_b, x_c und y_c bekannt sind und d₁ und d₂ bereits ermittelt wurden, und mit

k3 = 4(–d21 (1 + 21 ) + (c1(xa – xb) + ya – yb)2), (40)wobei mit

• • x ' / b eine erste Teil-Positionsangabe der Referenzeinheit b bezogen die erste Koordinatenrichtung auf einem Kreis mit dem Radius des Abstands der Referenzeinheit b zum Staubsauger-Roboter 1 (Objekt m) und auf einer Verlängerung einer geraden Linie zwischen dem Staubsauger-Roboter 1 und der Referenzeinheit a (l_am),
• • y ' / b eine zweite Teil-Positionsangabe der Referenzeinheit b bezogen auf die zweite Koordinatenrichtung auf einem Kreis mit dem Radius des Abstands der Referenzeinheit b zum Staubsauger-Roboter 1 und auf der Verlängerung der geraden Linie zwischen dem Staubsauger-Roboter 1 und der Referenzeinheit a (l_am),
• • x ' / c eine erste Teil-Positionsangabe der Referenzeinheit c bezogen auf die erste Koordinatenrichtung auf einem Kreis mit dem Radius des Abstands der Referenzeinheit c zum Staubsauger-Roboter 1 und auf der Verlängerung der geraden Linie zwischen dem Staubsauger-Roboter 1 und der Referenzeinheit a (l_am),
• • y ' / c eine zweite Teil-Positionsangabe der Referenzeinheit c bezogen auf die zweite Koordinatenrichtung auf einem Kreis mit dem Radius des Abstands der Referenzeinheit c zum Staubsauger-Roboter 1 und auf der Verlängerung der geraden Linie zwischen dem Staubsauger-Roboter 1 und der Referenzeinheit a (l_am),
• • x_a die erste Teil-Positionsangabe der Referenzeinheit a bezogen auf die erste Koordinatenrichtung,
• • y_a die zweite Teil-Positionsangabe der Referenzeinheit a bezogen auf eine zweite Koordinatenrichtung,
• • x_b die erste Teil-Positionsangabe der Referenzeinheit b bezogen auf die erste Koordinatenrichtung,
• • y_b die zweite Teil-Positionsangabe der Referenzeinheit b bezogen auf die zweite Koordinatenrichtung,
• • x_c die erste Teil-Positionsangabe der Referenzeinheit c bezogen auf die erste Koordinatenrichtung,
• • y_c die zweite Teil-Positionsangabe der Referenzeinheit c bezogen auf die zweite Koordinatenrichtung,
• • x_m die erste Teil-Positionsangabe des Staubsauger-Roboters 1 bezogen auf die erste Koordinatenrichtung, und
• • y_m die zweite Teil-Positionsangabe des Staubsauger-Roboters 1 bezogen auf die zweite Koordinatenrichtung bezeichnet wird.

From the provisions (21) to (33) the following rules can be established: x m = c 1 · y m + c 2 , (34) With

where x _a , y _a , x _b , y _b , x _c and y _{c are} known and d ₁ and d _{2 have} already been determined, and with

k 3 = 4 (-d 2 1 (1 + 2 1 ) + (c 1 (x a - x b ) + y a - y b ) 2 ) (40) being with

• • x '/ b a first partial position information of the reference unit b related the first coordinate direction on a circle with the radius of the distance of the reference unit b to the vacuum cleaner robot 1 (Object m) and on an extension of a straight line between the vacuum cleaner robot 1 and the reference unit a (l _am ),
• • y '/ b a second partial position information of the reference unit b with respect to the second coordinate direction on a circle with the radius of the distance of the reference unit b to the vacuum cleaner robot 1 and on the extension of the straight line between the vacuum cleaner robot 1 and the reference unit a (l _am ),
• • x '/ c a first partial position information of the reference unit c with respect to the first coordinate direction on a circle with the radius of the distance of the reference unit c to the vacuum cleaner robot 1 and on the Extension of the straight line between the vacuum cleaner robot 1 and the reference unit a (l _am ),
• • y '/ c a second partial position information of the reference unit c with respect to the second coordinate direction on a circle with the radius of the distance of the reference unit c to the vacuum cleaner robot 1 and on the extension of the straight line between the vacuum cleaner robot 1 and the reference unit a (l _am ),
• X _{a is} the first partial position specification of the reference unit a with respect to the first coordinate direction,
• Y _a the second partial position specification of the reference unit a with respect to a second coordinate direction,
• X _{b is} the first partial position specification of the reference unit b with respect to the first coordinate direction,
• Y _{b is} the second partial position specification of the reference unit b relative to the second coordinate direction,
• X _c the first partial position specification of the reference unit c with respect to the first coordinate direction,
• Y _c the second partial position specification of the reference unit c with respect to the second coordinate direction,
• • x _{m is} the first partial position of the vacuum cleaner robot 1 with respect to the first coordinate direction, and
• • y _{m is} the second partial position of the vacuum cleaner robot 1 referred to the second coordinate direction.

Due to the quadratic relationship given above, there are two potential locations for the vacuum cleaner robot 1 (Object m), namely x _m1 , y _m1 and x _m2 , y _m2 . The correct position can be determined unambiguously by calculating the path differences d ₁ , d ₂ (delta distances ₎ for both positions using the following instructions and then comparing them with the value pair d ₁ , d ₂ determined by means of the above-mentioned rules:

If the value pair d ₁ , d ₂ determined by means of the abovementioned rules coincides with the recalculated value pair d ₁ , d ₂ , the correct position indication is determined.

There are also items for which the counterparty calculator returns the same recalculated value pair d ₁ , d ₂ in both cases. In such a case, a plausibility analysis selects the correct position indication from the two possible position indications.

Second embodiment

The following is with reference to 1 and 3 a second embodiment of the system according to the invention described. The system according to the second embodiment of the invention is basically the same as the system according to the first embodiment of the invention, except that an object m, in this embodiment, is a PDA 2 (Personal Digital Assistant) and a search object, as in this embodiment, a product or product P, which is stored in a department store or department store K, are provided.

The PDA 2 has a radio receiving unit 22 , a radio transmission unit 23 and a microprocessor 21 to control the PDA 2 on. The microprocessor 21 has the three devices described in the first embodiment realized in the form of a computer program.

The PDA 2 is set up to have a navigation system. This system may indicate to a user the location of the searched product P based on direction and distance.

To do this, the user selects one in the PDA 2 stored program routine in which the PDA 2 via its radio transmission unit 23 emits a search signal which is received by the reference units a, b, c distributed in the department store K via their respective radio receiving unit. This search signal contains a code associated with the searched product P and at the same time serves as a localization radio signal for locating the PDA 2 used, the process of locating the PDA 2 proceeds according to the localization method described in the first embodiment.

Furthermore, the product P has a radio transmission unit, by means of which the product P in vorbestimm th time intervals a localization radio signal emits, which contains the code associated with the product and which is received by the reference units a, b, c via their respective radio receiving unit. Based on the localization radio signal emitted by the product P, the position of the product P may be the same as that of the PDA 2 can be determined. Alternatively, several products P of the same kind may be stored in a shelf or the like, wherein a localization radio signal is transmitted at predetermined time intervals via a provided on this shelf wireless transmitter unit containing a code stored in this shelf associated products code.

In this embodiment, since the PDA 2 also with a radio receiver unit 22 is provided, all in the localization of the PDA 2 and the product P required data from the reference units a, b, c via their respective radio transmission unit to the PDA 2 be transmitted. The determination of the respective position of the PDA 2 and the product P is then found in the PDA 2 instead of.

After the position of the PDA 2 and the position of the product P has been determined, the user is based on the position of the PDA 2 the direction in which the desired product P is located and the distance of the product to the PDA 2 displayed. If necessary, the search procedure described above can be repeated until the user has found the product P.

Third embodiment

in the Following is a third embodiment of the system according to the invention described. The system according to the third embodiment The invention is essentially the same as the system according to the first embodiment of the invention, except that the object m in this embodiment is a person who carries a radio transmitter unit with him and is in an exhibition or a museum.

The Radio transmission unit can, for example, a built-in PDA Radio transmission unit, a radio transmission unit of a mobile phone or be a separate mini radio transmitter. In this embodiment the radio transmitting unit is a separate mini-radio transmitter belonging to the person handed on entering the museum becomes.

Of the Mini-radio transmitter sends a localization radio signal at predetermined time intervals that has a specific code associated with the mini-radio transmitter contains and which of the reference units a, b, c receive via their respective radio receiving unit becomes. Based on the mini-radio transmitter emitted specific localization radio signal, the current position of the mini-radio transmitter and thus the current position of the mini-radio transmitter leading oneself Person to be determined, the process of locating the Miniature radio transmitter according to the localization method described in the first embodiment expires.

at this embodiment is because the mini radio transmitter over no radio receiving unit has that Position of the mini radio transmitter determined in the reference units a, b, c. The determined position of the mini-radio transmitter or the mini-radio transmitter with leading Person is from the reference units a, b, c via their radio transmission unit transmitted to a central computer. Alternatively, the transmission the position of the mini-radio transmitter also via a data cable, that the reference units a, b, c and the central computer with each other connects to the data exchange.

Of the Central computer has a map of the museum in a storage unit saved with the exhibition objects that are in the museum. The central computer compares the current position of the mini-radio transmitter with the saved positions of the exhibition objects.

If the mini radio transmitter is located near a certain exhibition object the central computer sends via a data cable or via radio a control signal to an audio unit, which in this particular Exhibit is installed. The audio unit then plays an audio information associated with the particular exhibit which was previously stored in the audio unit. The audio information is about a Loudspeaker issued by the particular exhibition object is installed.

alternative the speaker can be integrated in a headphone unit, the one radio receiver unit wherein the audio information is via one in the audio unit provided radio transmitter unit to the radio receiver unit of the headphone unit is sent and then over the loudspeaker, i. the headphones, is issued.

alternative The output of the information can also be displayed on a screen take place, which is provided for the particular exhibit object.

With The positioning of the person can the person, targeted information transmitted such as historical information about each Exhibition objects of the museum.

It It should be noted that the system according to the invention and the method according to the invention preferably in the areas of robot localization, warehouse automation, In-house localization, Warehouse tracking and e-commerce can be used.

• [1] J. Borenstein, H. R. Everett, and L. Feng. „Where am I?" Sensors and methods for mobile robot positioning. Technical report, University of Michigan, Apr. 1996.
• [2] J. Hightower and G. Borriello. "Location Systems for Ubiquitous Computing" Computer, 34(8): 57-66, August 2001.
• [3] P.-H. Dana "Global positioning system overview" http://www.colorado.edu/geography/gcraft/notes/gps/gps.html, 2000.
• [4] N. B. Priyantha, A. Chakraborty, and H. Balakrishnan. "The Cricket location-support system", Mobile Computing and Networking, Seiten 32-43, 2000.

This document cites the following publications:

• [1] J. Borenstein, HR Everett, and L. Feng. "Where at I", "Sensors and Methods for Mobile Robot Positioning." Technical report, University of Michigan, Apr. 1996.
• [2] J. Hightower and G. Borriello. "Location Systems for Ubiquitous Computing" Computer, 34 (8): 57-66, August 2001.
• [3] P.-H. Dana "Global positioning system overview" http://www.colorado.edu/geography/gcraft/notes/gps/gps.html, 2000.
• [4] NB Priyantha, A. Chakraborty, and H. Balakrishnan. "The Cricket location-support system", Mobile Computing and Networking, pages 32-43, 2000.

a

reference unit

b

reference unit

c

reference unit

m

object

l _bm

spatially shortest distance between the

reference unit b and the object m

l _cm

spatially shortest distance between the

reference unit c and the object m

l _am

spatially shortest distance between the

reference unit a and the object m

l _off

spatially shortest distance between the

reference unit a and the reference unit b

l _ac

spatially shortest distance between the

reference unit a and the reference unit c

l _bc

spatially shortest distance between the

reference unit b and the reference unit c

x _a

Part position statement the reference unit a based on

the Coordinate direction x

y _a

Part position statement the reference unit a based on

the Coordinate direction y

x _b

Part position statement the reference unit b based on

the Coordinate direction x

y _b

Part position statement the reference unit b based on

the Coordinate direction y

x _c

Part position statement the reference unit c based on

the Coordinate direction x

y _c

Part position statement the reference unit c based on

the Coordinate direction y

x _m

Part position statement of the object relative to the

coordinate direction x

y _m

Part position statement of the object relative to the

coordinate direction y

x '/ b

Part position statement the reference unit b based on

the Coordinate direction x on a circle with the radius

of Distance of the reference unit b to the object m and on

one renewal a straight line between the

Object m and the reference unit a (l _am ).

y '/ b

Part position statement the reference unit b based on

the Coordinate direction y on a circle with the radius

of Distance of the reference unit b to the object m and on

of the renewal the straight line between the object m

and the reference unit a (l _am ).

x '/ c

Part position statement the reference unit c based on

the Coordinate direction x on a circle with the radius

of Distance of the reference unit c to the object m and on

of the renewal the straight line between the object m

and the reference unit a (l _am ).

y '/ c

Part position statement the reference unit c based on

the Coordinate direction y on a circle with the radius

of Distance of the reference unit c to the object m and on

of the renewal the straight line between the object m

and the reference unit a (l _am ).

S

Sensor (s)

W

Living room

1

Vacuum cleaner robot

11

microprocessor

12

drive unit

13

Radio receiver unit

14

Radio transmission unit

15

suction unit

P

product or goods

K

department store

2

PDA (Personal Digital Assistant)

21

microprocessor

22

Radio receiver unit

23

Radio transmission unit

Claims (14)

Method for determining a position of a object, • at a temporal relation of signal transit times between at least three reference units exchanged signals determined becomes, • at sent from the object a signal to the reference units becomes, • at the signal propagation time differences are formed which the differences the respective signal propagation times of the signal transmitted by the object describe to the reference units, • when using the Signal transit time differences, the temporal relation of signal transit times and considering the positions of the reference units determines the position of the object becomes. Method according to claim 1, in which the reference units and the object each have the same speed have running clocks. Method according to claim 1 or 2, in which uses as signals electromagnetic signals become. Method according to one the claims 1 to 3, • at the temporal relation of the signal propagation times is determined, by carrying out at least two reference measurements, • where in a first reference measurement, a first of the at least three reference units sends a first reference signal to the other reference units, • where in a second reference measurement, a second of the at least three reference units sends a second reference signal to the other reference units, • where in both reference measurements respectively the reference signal reception times be captured, and taking into account the position of the Referenzeinheiten the respective reference signal transit times are determined. Method according to Claim 4, in which the temporal relation of the signal propagation times is determined using the following rules, taking into account the first reference measurement, the following rules are used: t from + t s, b + Δt b = t r, ba + Δt a . t bc + t s, b + Δt b = t r, bc + Δt c . .delta.t a - Δt c = t from - t bc - t r, ba + t r, bc . where with • t _from the signal delay between a reference unit a and a reference unit b, • t _{s, b is} a local signal transmission time at the reference unit b, • .DELTA.t _{b is} a clock offset between a local time of the reference unit b and a fictitious global time, • t _{r , ba} a local signal reception timing in the reference unit a for one of the reference unit b to the reference unit a transmitted signal, • .DELTA.t _a a clock offset between a local time of the reference unit a and the fictitious global time, • tb _c is a signal propagation time between the reference unit b and a Reference unit c, • t _{r, bc is} a local signal reception time in the reference unit c for a signal sent by the reference unit b to the reference unit c signal, and • .DELTA.t _{c is} a clock offset between a local time of the reference unit c and the fictitious global time, denoted taking into account the second reference measurement the following regulations n be used: t ac + t s, c + Δt c = t r, ca + Δt a t bc + t s, c + Δt c = t r, cb + Δt b .delta.t a - Δt b = t ac - t bc - t r, ca + t r, cb . where with • t _ac a signal transit time between the reference unit a and the reference unit c, • t _{s, c} a local signal transmission time at the reference unit c, • t _r , _ca a local signal reception time in the reference unit a for a from the reference unit c to the reference unit a signal transmitted, and • t _{r, cb is} a local signal reception time in the reference unit b for a signal sent from the reference unit c to the reference unit b signal is designated. Method according to claim 4 or 5, • at the signal propagation time differences of the object to the reference units transmitted signal using the reference signal reception times and the reference signal transit times are formed, and • in which for determining the position of the object, runway differences of taken into account by the object sent to the reference units become. Method according to claim 6, wherein the differences in running distances are determined using the following rules: d 1 = (t r, ma - t r, mb + t ac - t bc - t r, ca + t r, cb ) · V p d 2 = (t r, ma - t r, mc + t from - t bc - t r, ba + t r, bc ) · V p with d _1, a run-path difference of the signal sent by the object to the reference units between the reference units a and b, d _2, a difference in run-path between the reference units a and c of the signal transmitted by the object to the reference units, t _r , _ma local signal reception time in the reference unit a for the signal sent from the object to the reference units, t _{r, mb} a local signal reception time in the reference unit b for the signal sent by the object to the reference units, and t _r , _mc a local signal reception time in the reference unit c for the object from the reference unit transmitted signal, is called. Method according to claim 7, wherein the position of the object is determined according to the following rules: x m = c 1 · y m + c 2 . With

• x _a a first sub-position information of the reference unit a relative to a first coordinate direction, • y _a a second sub-position information of the reference unit a with respect to a second coordinate direction, • x _b a first sub-position information of the reference unit b, based on the first coordinate direction • y _b a second partial position information of the reference unit b with respect to the second coordinate direction, • x _c a first partial position information of the reference unit c with respect to the first coordinate direction, • y _c a second partial position information of the reference unit c with respect to the second Coordinate direction, x _{m is} a first partial position specification of the object relative to the first coordinate direction, and y _{m is} a second partial position specification of the object relative to the second coordinate direction, is called. Method according to one the claims 1 to 8, where the position of the object in the object is determined. Method according to one the claims 1 to 9, in which an autonomous system is used as object, which depends controlled by the determined position. Method according to one the claims 1 to 9, used in one of the following areas: robot localization, Warehouse automation, in-house localization, Warehouse tracking or e-commerce. System for determining a position of an object, With • at least three reference units which are arranged to send and for receiving signals, and • with a facility for Determining a temporal relation of signal transit times between signals exchanged between the reference units, • with a Object arranged to send a signal to the reference units, • with a Device for determining signal propagation time differences, which the differences of the respective signal propagation times of the object Describe the transmitted signal to the reference units, and • with a Device for determining the position of the object using the signal propagation time differences, the temporal relation of signal propagation times and considering the positions of the reference units. System according to claim 12, wherein the object is a receiver for receiving a signal. System according to claim 12 or 13, wherein the reference units and the object are each equally fast have running clocks.