DE102019211812A1 - Method for locating an object - Google Patents

Abstract

A method for locating an object (60) by means of a global satellite system, the satellite system comprising a number of communication units, with at least one transmission unit (72), which sends a satellite signal, and at least one reception unit (70), which receives satellite signals, being provided as communication units are, the object (60) serves as a communication unit, at least one of the at least one transmission unit (72) is controlled in such a way that it transmits a satellite signal with varying power, and the at least one receiving unit (70) evaluates the received satellite signals in order to To determine the location of the object (60).

Description

The invention relates to a method for locating an object and an arrangement for performing the method.

Positioning refers to processes that are used to determine the spatial position of distant objects, especially in relation to the observer. In a broader sense, localization based on received signals is also referred to as location. This includes, in particular, localization using a global navigation satellite system (GNSS). Localization is also understood here to be what is known as location determination, namely the determination of one's own location.

A GNSS is a system for determining position and navigation by receiving signals from navigation satellites and pseudolites. A pseudolite (composed of pseudo and satellite) is a terrestrial transmitter that sends out signals that mimic signals sent by satellites. Pseudolites are used, for example, to locally increase the measurement accuracy of satellite-based navigation systems.

It should be noted that GNSS is a collective term for the use of existing and future global satellite systems, such as NAVSTAR GPS, GLONASS, Galileo, Beidou, etc. The method presented is not restricted to any of these systems.

In a known method, the object to be localized can also transmit signals on the GPS frequency, which are registered by stationary receivers. The position of the object can be calculated based on the transit times.

From the pamphlet DE 10 2016 225 886 A1 a method and a device for determining position are known for this purpose. In the method, at least one signal is transmitted from at least one object to at least two stationary receiving stations on at least one carrier frequency of a satellite-supported navigation system. At least one transit time difference is calculated for respective signals received by the at least two stationary receiving stations. A current position of the at least one object relative to the at least two receiving stations is calculated on the basis of the at least one transit time difference. In contrast to the previously described technology with stationary pseudolites that send a pseudo signal, here the moving object to be located or localized sends pseudo-satellite signals.

The pamphlet DE 10 2005 015 326 A1 describes a method for the detection of objects that are enclosed in a medium. A locating device for locating such enclosed objects is also described. Furthermore, a measurement signal correlated with an object is measured, from which a second signal is generated which reproduces a measured signal strength of the measurement signal in a segmented manner, with individual segment units of the second signal being varied depending on the measured signal strength of the measurement signal.

When locating objects in buildings, it turns out to be problematic that the signals from both satellites and pseudolites are attenuated by building walls. In addition, especially with pseudolites, the law of distance must be observed, which describes the decrease in a physical quantity with increasing distance from the source or the transmitter. Since there is a quadratic dependency between distance and intensity, this means that the intensity falls to a quarter of the initial value when the distance is doubled. In the case of satellites that are located a great distance from the objects to be located, this plays a minor role. In the case of pseudolites that may be in the immediate vicinity of the object to be located, this dependency must be observed.

Disclosure of the invention

Against this background, a method according to claim 1 and an arrangement with the features of claim 11 are presented. Further developments of the invention emerge from the dependent claims and the description.

A method for locating an object by means of a global satellite system is presented, the satellite system comprising a number of communication units, the communication units being at least one transmission unit, which sends a satellite signal, and at least one reception unit, the satellite signals are provided, the object serving as a communication unit, at least one of the at least one transmitting unit being controlled so that it sends a satellite signal with varying power, and the at least one receiving unit evaluates the received satellite signals to determine the location of the property. In the variation of the power, which can be set by a control, for example information that the satellite signal carries, but also additionally or alternatively the location at which the object is located, can be taken into account.

With the method presented, it is now possible to use an existing GNSS, for example GPS reception technology (GPS: global positioning system), largely unchanged for so-called indoor localization, i.e. H. a localization in a building. In one embodiment, this is also possible when the signal strength differs very strongly at short distances between the transmitter and receiver.

Furthermore, the localization can be improved with the help of the satellites in poor reception conditions with regard to time to first fix. If necessary, it is also accepted that the reception conditions worsen a little under good conditions. Time to First Fix is the time a GPS receiver needs before it can determine its position for the first time after being switched on.

The arrangement described is used to carry out the method presented and is implemented, for example, in hardware and / or software.

Further advantages and configurations of the invention emerge from the description and the accompanying drawings.

It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the respectively specified combination, but also in other combinations or on their own, without departing from the scope of the present invention.

Figure list

• 1 shows an arrangement of pseudolites.
• 2 shows an arrangement of stationary receiving stations and an object for locating the object in a building according to a known method.
• 3 shows a possible scenario of a possible implementation of the described method.

Embodiments of the invention.

The invention is shown schematically on the basis of embodiments in the drawings and is described below with reference to the drawings.

1 shows an arrangement with transmitting and receiving units for carrying out a location, all with reference number 10 is designated. The illustration shows an object to be located 12 , in this case a GPS user, a first pseudolite 14th , a second pseudolite 16 , a third pseudolite 18th , a fourth pseudolite 20th and a reference station 22nd . Between the reference station 22nd and the object 12 there is also a wireless connection 24 .

The dashed lines show the transmission of the satellite signals and the solid lines show the transmission of the reference values from the reference station 22nd to the object 12 whose position is to be determined.

Due to the distance law mentioned at the beginning, the intensities are that of the object 12 The signals received may differ greatly, so that signals may overlap. This is where the invention comes in.

In 2 is an arrangement for determining the position of an object 31 in a building 33 shown operating according to a known method. By means of stationary Receiving stations 35 , 37 , 39 , 41 , 43 and 45 , for example, by a fire brigade on respective windows of the building 33 can be set up very quickly, a position of the object 31 in the building 33 can be determined by taking a runtime difference one of the object 31 transmitted signal 47 between respective stationary receiving stations 35 , 37 , 39 , 41 and 43 is determined. Because the signal 47 the stationary receiving station 45 is not reached, this is when determining the position of the object 31 not used.

The object 31 can be used for orientation within the building 33 used even when in the building 33 For example, visibility is poor due to a fire.

3 shows a scenario according to an embodiment of the method described herein. The illustration shows an object 60 , in this case a vehicle that is in a building 62 is located. This building 62 includes a number of walls 64 and a blanket 66 .

In the object 60 are a receiving unit 70 and a transmitter unit 72 intended for sending and receiving satellite navigation signals. The illustration also shows a first pseudolite 80 , a second pseudolite 82 , a satellite 84 and a cloud 86 .

It can be seen that the satellite signals sent through the walls 64 and the ceiling 66 , especially depending on the location of the property 60 , be dampened differently. The distance law must also be observed. This has the consequence that satellite signals with high intensity overlap satellite signals with low intensity, which can lead to the location being impaired. By varying the emitted power of at least one of the satellite signals, this overlap is eliminated at least in a certain time range. In turn, this area is sufficient for reliable localization to be carried out.

In the method presented, it is provided that pseusolites, GPS transmitters or GPS satellites vary their transmission power. For example, the transmission power can be varied with each bit of the C / A or P code.

The C / A code is a pseudo-random code sequence with a length of 1023 bits that is used for modulating a data signal, in this case the satellite signal. The transmission bits of a code sequence are referred to as so-called chips in modulation and do not carry any user information, but are only used for demodulation by correlation with the code sequence itself. The longer P-code uses so-called JPL sequences (JPL: Jet Propulsion Labs) as a code generator.

The variation can therefore take place either stochastically or, like the C / A or P codes, with the aid of pseudo-random data sequences. Each bit of the data sequence determines whether the transmission power is reduced or increased compared to the previous transmission. Alternatively, the transmission power of complete C / A or P-code data sequences can be changed with each bit. However, it is also conceivable that the performance of several C / A or P code data sequences can be changed one after the other with one bit. When the method described is used with pseudolites, this has the advantage, on the one hand, that pseudolites located in the vicinity cannot permanently mask the signals of distant pseudolites. When used in existing satellites, this can ensure that signals received only indirectly cannot be covered by signals received directly. On the other hand, with the help of the coded power control, satellites with a large number of pseudolites and also a large number of pseudolites can be distinguished from one another, even if they use the same C / A or P codes to encode the phase position of the signal.

Several data sequences can be superimposed on one another, whereby the increase in performance can be further increased. In addition, even more pseudolites can be made distinguishable from one another through the overlay.

• Ein GPS-Sender codiert seine Signale mit Hilfe der SV PRN ID 1 (SV: Space Vehicle, PRN: Pseudo Random Noise: Pseudozufallsrauschen), die durch die Chipfolge 1100100000 definiert ist, wobei der Wechsel zwischen einer 1 und einer 0 eine Phasenverschiebung der Trägerfrequenz um 180° bewirkt. Allerdings passt der Sender mit dem vorgeschlagenen Verfahren neuerdings nach 10 Chips die Leistung gemäß SV PRN ID 2 an: Wenn die Chipfolge der SV PRN ID 2 (1110010000) eine 1 zurückliefert, verdreifacht der Sender die Leistung. Zusätzlich passt der Sender nach 1023 Chips die Leistung gemäß SV PRN ID 3 (1111001000) an: Wenn die Chipfolge SV PRN ID 3 eine 1 zurückliefert, verzehnfacht der Sender die Leistung zusätzlich. Wenn sowohl ID 2 als auch ID 3 eine 1 zurückliefern, dann führt das dazu, dass der Sender die Leistung verdreißigfacht.

An example is given below:

• A GPS transmitter encodes its signals using the SV PRN ID 1 (SV: Space Vehicle, PRN: Pseudo Random Noise), which is defined by the chip sequence 1100100000, whereby the change between a 1 and a 0 represents a phase shift in the carrier frequency caused by 180 °. However, with the proposed method, the transmitter now adapts the power according to SV PRN ID 2 after 10 chips: If the chip sequence of SV PRN ID 2 (1110010000) returns a 1, the transmitter triples the power. In addition, the transmitter adjusts the power according to SV PRN ID 3 (1111001000) after 1023 chips: If the chip sequence SV PRN ID 3 returns a 1, the transmitter increases the power tenfold. If both ID 2 and ID 3 return a 1, the result is that the transmitter thirty-fold.

In general, other pseudo-random sequences can also be used for power control. However, it is advisable to use pseudo-random sequences for the power control that are already stored in the memory of the transmitter and receiver. This can save resources.

For each bit of the C / A or P code, individual data sequences can be used to vary the transmission power. The length of the pseudo-random data sequences for the power adjustment can be chosen to be just as long as the C / A or P codes.

If the variation occurs with the help of pseudo-random data sequences, the receivers can optionally be modified so that they also adapt the expected received levels according to the pseudo-random data sequences before they cross-correlate the expected levels with the received levels. The pseudo-random data sequences should be selected as usual in such a way that, as before, with other code phases, namely the code phases of the other satellites, they have a minimal cross-correlation and likewise only a single maximum occurs.

In an embodiment, the pseudolites use pseudo-random data sequences which are not used by any of the satellites and which behave as orthogonally as possible to the pseudo-random data sequences used. Alternatively, however, the pseudolites can also use the pseudo-random data sequences from satellites that are currently not visible on the horizon.

If the object to be localized sends signals on GPS frequencies that are registered by stationary receivers and the position of the object is calculated based on the transit times, then the following power control is particularly effective. The objects to be localized increase the transmission power step by step until localization is possible with the aid of the stationary receiver. The information on the current position of the object is received via a second channel, such as WLAN, Bluetooth or GSM. As soon as the position of the object is to be determined again, the object checks whether it is now possible to receive the satellite signals. If reception is still not possible, the object begins again to gradually increase the transmission power. This procedure ensures that the GPS frequency bands are only "disturbed" by the pseudolites to the extent that this is absolutely necessary for localization.

For example, stationary GPS receivers can be attached to the entrance and exit of a tunnel so that they can constantly receive enough satellite signals to be able to calculate the exact time at any time. When a vehicle has entered a tunnel so far that it can no longer receive enough satellite signals, it starts sending signals via its own GPS antenna. These signals are detected by the GPS antennas of the stationary receivers at the tunnel openings and sent to a server with the current time stamp. This calculates, for example, the current position of the vehicle using the transit time method and sends it z. B. via GSM, LTE, UWB or another cellular connection to the vehicle.

If the pseudolites also use 32 P-codes for signal coding and 64 by 64 P-codes for signal strength modulation, then there are over 131,072 possible combinations. This means that even in Germany's largest stadium, every single visitor could be located using this method.

If there are not enough other unused, approximately orthogonal pseudo-random sequences available, then new sequences with more than 10 chips can also be generated, which can then be better distinguished from existing pseudo-random sequences. In general, pseudo-random sequences that are currently used by satellites in the vicinity can also be used for phase coding. Since faulty satellite signals are very often due to multipath reception, the receivers are robust against this interference and can still calculate an exact position.

• - Kaufhaus, Shopping Mall,
• - Parkhaus, Tiefgarage,
• - Tunnel, U-Bahnhof,
• - überdachte Verkehrswege,
• - Wohnhäuser, Öffentliche Gebäude, Werkshallen.

Localization can be improved particularly well in the following areas:

• - Department store, shopping mall,
• - multi-storey car park, underground car park,
• - tunnel, subway station,
• - covered traffic routes,
• - Residential houses, public buildings, factories.

• - Bei den bestehenden Satelliten kann die Energieversorgung weiterhin verwendet werden. Es müssen nur die Leistungsregelung und der Leistungspuffer angepasst werden.
• - Ein GPS-Empfang ist auch unter schlechten Bedingungen schneller und mit geringerem Energieeinsatz möglich.
• - Eine gebäudegenaue Ortung ist auch nur anhand der Satellitensignale mit wenig Energieeinsatz in tiefen Kellern möglich.
• - Durch die zusätzliche Auswertung der Amplitude können eine Vielzahl neuer Sender voneinander unterschieden werden. Dadurch sinkt die Verwechslungsgefahr von Pseudoliten mit echten Satelliten.
• - Der Einfluss der Pseudoliten auf die Ortung mit Hilfe der GPS-Satelliten ist vernachlässigbar klein und ist nur in sehr kurzem Abstand zu Gebäuden nachweisbar, in denen das Verfahren zum Einsatz kommt.
• - Bei dreidimensionaler Bewegungsmöglichkeit ist die Höhe mit Hilfe von vier stationären Einheiten bzw. Pseudoliten berechenbar.
• - Gegenüber einer Kreuzpeilung, bei der die Sendesignalstärke so lange erhöht wird, bis es ein Empfänger wahrnehmen kann, können mit dem Verfahren sehr viel mehr Sender auf engem Raum betrieben werden, ohne dass der Sendezeitpunkt von zentraler Stelle koordiniert werden muss.
• - Wände zwischen Sender und Empfänger dämpfen und reflektieren die Signale. Reflektierte Signale, die indirekt zwischen Sender und Empfänger ausgetauscht werden, sind zwar stärker, benötigen aber längere Zeit, bis sie beim Empfänger ankommen, als die direkten aber stark gedämpften Signale. Durch die Modulation mit Hilfe der Pseudocodes können die stark gedämpften Signale besser von den über Umwege reflektierten Signalen unterschieden werden, wodurch sich die Genauigkeit innerhalb von Gebäuden enorm steigern lässt. Hierin liegt auch der Vorteil gegenüber einer Intensitäts-basierten Ortung wie bspw. WLAN, oder einer laufzeitbasierten Ortung mittels UWB (Ultra-wideband)
• - Der Aufwand, um eine Indoorlokalisierung zu realisieren, ist verglichen mit anderen Verfahren sehr gering, wenn vorausgesetzt wird, dass ein GPS- und Internet-fähiges Gerät indoor lokalisiert werden soll (Smartphone, Smartwatch, Fahrzeug, ...). Für diesen Fall sind lediglich ausreichend, Internet-fähige Geräte innerhalb des Gebäudes mit GPS auszurüsten, die möglichst so platziert werden, dass sie auch GPS-Empfang haben.

The method presented has a number of advantages, at least in some of the versions:

• - The energy supply can still be used with the existing satellites. Only the power control and the power buffer need to be adjusted.
• - GPS reception is possible even under poor conditions, faster and with less energy consumption.
• - A building-precise localization is also possible in deep basements with only the satellite signals with little use of energy.
• - The additional evaluation of the amplitude enables a large number of new transmitters to be distinguished from one another. This reduces the likelihood of confusing pseudolites with real satellites.
• - The influence of the pseudolites on the location with the aid of the GPS satellites is negligibly small and can only be detected at a very short distance from the buildings in which the method is used.
• - With three-dimensional movement possibilities, the height can be calculated with the help of four stationary units or pseudolites.
• - Compared to a cross bearing, in which the transmission signal strength is increased until a receiver can perceive it, the method allows many more transmitters to be operated in a confined space without the transmission time having to be coordinated from a central point.
• - Walls between transmitter and receiver attenuate and reflect the signals. Reflected signals that are exchanged indirectly between the transmitter and receiver are stronger, but need a longer time to reach the receiver than the direct but strongly attenuated signals. By modulating with the help of the pseudo codes, the strongly attenuated signals can be better distinguished from the signals reflected via detours, whereby the accuracy within buildings can be increased enormously. This also has the advantage over intensity-based location such as WLAN, or runtime-based location using UWB (Ultra-wideband)
• - The effort to implement indoor localization is very low compared to other methods if it is assumed that a GPS and Internet-capable device is to be localized indoors (smartphone, smartwatch, vehicle, ...). In this case, it is only sufficient to equip internet-capable devices within the building with GPS, which are placed where possible so that they also have GPS reception.

A table of the PRN numbers is given below. SV PRN ID G2 phase taps First 10 chips 1 2 & 6 1100100000 2 3 & 7 1110010000 3 4 & 8 1111001000 4th 5 & 9 1111100100 5 1 & 9 1001011011 6th 2 & 10 1100101101 7th 1 & 8 1001011001 8th 2 & 9 1100101100 9 3 & 10 1110010110 10 2 & 3 1101000100 11 3 & 4 1110100010 12 5 & 6 1111101000 13 6 & 7 1111110100 14th 7 & 8 1111111010 15th 8 & 9 1111111101 16 9 & 10 1111111110 17th 1 & 4 1001101110 18th 2 & 5 1100110111 19th 3 & 6 1110011011 20th 4 & 7 1111001101 21st 5 & 8 1111100110 22nd 6 & 9 1111110011 23 1 & 3 1000110011 24 4 & 6 1111000110 25th 5 & 7 1111100011 26th 6 & 8 1111110001 27 7 & 9 1111111000 28 8 & 10 1111111100 29 1 & 6 1001010111 30th 2 & 7 1100101011 31 3 & 8 1110010101 32 4 & 9 1111001010

For the first 10 chips shown in the table, a 1 could correspond to high power and a 0 to low power. This shows that the signal is always sent with a low power after a certain period of time. The signal thus carries information, in this case the modulated sequence of 0s and 1s, the power being varied as a function of these values and thus as a function of the information carried by the signal.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102016225886 A1 [0006]
• DE 102005015326 A1 [0007]

Claims (12)

A method for locating an object (12, 60) by means of a global satellite system, the satellite system comprising a number of communication units, wherein at least one transmission unit (72), which transmits a satellite signal, and at least one reception unit (70), which receives satellite signals, are provided as communication units, the object (12, 60) serves as a communication unit, at least one of the at least one transmission unit (72) is controlled in such a way that it transmits a satellite signal with varying power, and the at least one receiving unit (70) evaluates the received satellite signals in order to determine the location of the object (12, 60). Procedure according to Claim 1 , in which the power is varied as a function of information carried by the satellite signal. Procedure according to Claim 1 or 2 in which the at least one transmission unit (72) which transmits a signal with varying power, the power is regulated. Procedure according to Claim 3 , in which a pseudo-random sequence is used to regulate the power. Procedure according to Claim 4 , in which a C / A code is used to modulate the satellite signals. Procedure according to Claim 4 , in which a P-code is used to modulate the satellite signals. Method according to one of the Claims 1 to 3 , in which the power is varied depending on the location of the object (12, 60). Method according to one of the Claims 1 to 7th , in which at least one satellite is used as a transmitting unit (72) and / or receiving unit (70). Method according to one of the Claims 1 to 8th , in which at least one pseudolite (14, 16, 18, 20, 80, 82) is used as a transmitting unit (72) and / or receiving unit (70). Method according to one of the Claims 1 to 9 , in which the object to be localized (12, 60) is located in a building (62). Arrangement for locating an object (12, 60), which is used to carry out a method according to one of the Claims 1 to 10 is set up. Arrangement according to Claim 11 which has a computing unit for calculating the location of the object (12, 60).

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