FR3106216A1 - Method of providing a time and / or positioning service, regenerator device, corresponding receiver device and time server. - Google Patents

Abstract

A method of providing a time and / or positioning service is provided. At least one regenerator device (1) performs the following actions: calculating a time synchronized with GNSS time, as a function of the GNSS signals received; generation of a position and time signal (SPT signal) conveying time information, relating to time synchronized with GNSS time, and position information, relating to a position of the regenerator device; and transmitting the SPT signal. At least one receiver device (2) performs the following actions: reception and processing of at least one SPT signal (transmitted by a regenerator device) in order to extract therefrom time information, relating to a first time synchronized with GNSS time, and position information relating to a position of the regenerator device; and calculating a second time synchronized with the GNSS time, based on the information extracted. Abstract figure: Figure 1

Description

Method for providing a time and/or positioning service, corresponding regenerating device, receiving device and time server.

1. TECHNICAL AREA

The field of the invention is that of time and/or positioning systems, that is to say systems configured to provide a time and/or positioning service to receivers.

More specifically, the invention relates to a method for providing a time and/or positioning service, as well as a corresponding regenerator device, receiver device and time server.

The invention has numerous applications, such as in particular, but not exclusively, providing synchronization functions in time servers.

2. TECHNOLOGICAL BACKGROUND

In France, a first known solution to provide a time service is based on the “time signal”. According to the National Frequency Agency (ANFR), which manages all radio frequencies in France, the time signal is a reference signal produced from atomic clocks. Since 1977, it has been transmitted on the 162 kHz frequency, which was used until the end of 2016 to broadcast the France Inter program on the long waves. This signal is inaudible but, when picked up by an appropriate receiving device, it provides French legal time. Some companies carrying out a public service mission use this signal, as well as local authorities. Often referred to as the “France Inter time signal”, this service is widely used in key sectors of French industry to synchronize more than 200,000 clocks. This service provides a time reference of very high precision and reliability. It has the advantage that it can be better received in indoor spaces than other time bases, such as those of GPS (see discussion below) or mobile phone networks.

A drawback of the first known solution is that the continuity of the time broadcast by the “France Inter time signal” is not guaranteed. Another disadvantage is that the precision, although very high and highly reliable, is unsuited to technological developments which require ever greater precision.

A second known solution for providing a time and positioning service is based on one or more satellite positioning systems, also referred to by the acronym GNSS (for “Geolocation and Navigation by a Satellite System”). A GNSS system is a set of components based on a constellation of artificial satellites (hereinafter called GNSS satellites) rotating in orbit around the Earth and continuously transmitting signals (hereinafter called GNSS signals) towards it. GNSS satellites have extremely precise and synchronized atomic clocks, thus making it possible to define a universal clock called “GNSS time”. All GNSS signals are transmitted at the same known instant. Each GNSS satellite includes in its signal information giving its identity (satellite number) as well as the parameters of its orbit (necessary for the receiver so that the latter can estimate precisely and in real time the position of the GNSS satellite in the geocentric reference frame RG) . The GNSS signals are received and decoded by a receiver (hereinafter called GNSS receiver) carried by the user. This GNSS receiver provides the user with a so-called “PVT” solution:

• P (for “Position”): position of the receiver antenna (three coordinates);
• V (for "Speed"): receiver antenna speed (three coordinates);
• T (for “Time”): receiver time reference, synchronized with “GNSS time” (i.e. with the extremely precise atomic clocks of the GNSS satellites). The receiver's time reference (also called “time synchronized to GNSS time” below) comprises for example a synchronization signal PPS (for “Pulse Per Second”) and dating information.

There are currently several GNSS systems: GPS (developed by the United States), GALILEO (developed by the European Union), GLONASS (developed by Russia), etc.

The second known solution takes advantage of the advantages of GNSS systems, including global "land-air-sea" coverage, high time accuracy (10 to 20 ns with professional GNSS receivers) and low receiver cost. But it also suffers from its drawbacks, including:

• a low reception level (-160 dBm for example) makes GNSS receivers sensitive to reception conditions (masking phenomenon): there is thus no reception inside buildings (“indoor”) or in covered (dense forest for example) or in covered places (underground parking, car park, tunnels, etc.);
• reception difficulties between high buildings (urban canyon) with, in addition, the risk of receiving signals reflected on obstacles (buildings, mountains) then giving poor determination of the route, therefore poor localization and incorrect time transfer ;
• the low level of reception also makes GNSS receivers easy to cloak (it is possible to deaf and blind them by spraying them with a high-powered jamming signal in the reception band) or, worse, easy to decoy (by sending to the GNSS receiver a high power decoy signal in the receive band, containing "pseudo-satellite" information taking the place of real satellite information (coming from a real GNSS satellite) and providing location reference values and erroneous local time, thus leading the GNSS receiver to deduce its position and its local time in an erroneous way.

For example, in cases where the GNSS signals are no longer accessible due to masking, jamming or spoofing, it is no longer possible to exploit the GNSS time reference to perform a synchronization service.

As explained above, the fragility of GNSS signals is partly linked to their low level of reception. The latter is induced in particular by the distance of the GNSS satellites which are in medium earth orbit (MEO, for “Medium Earth Orbit” in English) at an altitude of between 19,000 and 23,000 km (19,100 km for the GLONASS system, 20200 km for the GPS system, 23222 km for the GALILEO system, etc.).

Based on this observation, two telecommunications service providers in the United States have each been offering, for several months, a time and positioning service (also called PNT service, for "Positioning, Navigation and Timing" in English) based on on their satellite infrastructure in Low Earth Orbit (LEO for “Low Earth Orbit” in English):

• the “STL” offer (for “Satellite Time and Location”) was developed by the American company Satelles; it provides a time and positioning solution completely independent of GPS (or other GNSS system); this solution is based on the Iridium constellation of 66 satellites in low earth orbit (LEO) and provides a signal 1000 times stronger than a GNSS signal, penetrating deep into buildings and capable of countering GNSS jamming without the aid of local infrastructure; in the event of interruption of reception of the GNSS signal or jamming, this solution makes it possible to switch to the reference time of the Iridium constellation, with a time precision of the order of 200 ns, i.e. a precision ten times lower than that GPS; And
• the “Echo Ridge / Globalstar” offer was developed by the American companies Echo Ridge and Globalstar; it provides a time and positioning solution completely independent of GPS (or other GNSS system); it is based on APS (Augmented Positioning System) technology which uses ordinary signals from communication satellites (and not GNSS signals) to produce precise position and timing information in compatible receivers; no new infrastructure is needed as it is based on Globalstar's constellation of 24 Low Earth Orbit (LEO) satellites and “Echo Ridge” software.

A drawback common to the two aforementioned offers is that their precision is much lower than that of a GNSS system (GPS or other) because they use ordinary signals from telecommunications satellites (Iridium constellation or Globalstar constellation), which are completely independent of GNSS signals.

3. OBJECTIVES

The invention, in at least one embodiment, aims in particular to overcome these various drawbacks of the state of the art.

More specifically, in at least one embodiment of the invention, an objective is to provide a solution making it possible to provide a time and/or positioning service, with an accuracy of the same order of magnitude as current GNSS systems (GPS , GALILEO, etc.), even when the GNSS signals cannot be used by the GNSS receivers (for whatever reason: masking, reception inside buildings, reception in a covered environment, reception in a place covered, reception between high buildings, jamming, decoy…).

Another objective of at least one embodiment of the invention is to provide such a solution, in a complementary or alternative manner to current GNSS systems.

Another objective of at least one embodiment of the invention is to provide such a solution which makes it possible to provide synchronization functions in time servers or any other equipment (device) which must benefit from a provision service of time and/or positioning.

Another objective of at least one embodiment of the invention is to provide such a solution making it possible to provide a time and/or positioning service which is robust, reliable and has global coverage.

Another objective of at least one embodiment of the invention is to provide such a solution which is based on a space segment consisting of a constellation comprising a small number of satellites, thus reducing the cost of the infrastructure .

Another objective of at least one embodiment of the invention is to provide such a solution which relies on a space segment consisting of a constellation of satellites built progressively.

Another objective of at least one embodiment of the invention is to provide such a solution which is based on a space segment consisting of a constellation of satellites which may not be dedicated to this solution, thus reducing the cost of the space segment deployment.

Another objective of at least one embodiment of the invention is to provide such a solution which is based on receivers that are simple to produce, inexpensive and do not require additional infrastructure on the ground.

4. SUMMARY

In a particular embodiment of the invention, there is proposed a regenerative device belonging to a time and/or positioning system; the regenerative device is on board a support located closer to the earth than the GNSS satellites and it comprises:

• a reception module, of the GNSS receiver type and configured to receive GNSS signals originating from GNSS satellites of at least one GNSS constellation and to calculate a time synchronized with the GNSS time, as a function of the GNSS signals received;
• means for generating a position and time signal (SPT) different from said GNSS signals and conveying time information, relating to said time synchronized to GNSS time, and position information, relating to a position of the regenerator device; And
• means for transmitting the position and time signal (SPT).

The proposed solution is based on a completely new and inventive approach consisting of combining two components:

• at least one regenerative device as mentioned above, that is to say embedded on a support located closer to the earth than the GNSS satellites, and configured to generate and transmit signals of a new type, called "position signals and time (SPT)", containing time information (relating to a (first) time synchronized to GNSS time and calculated from received GNSS signals) and position information (relating to the position of the regenerative device and, in a particular implementation, also calculated from received GNSS signals); And
• at least one receiver device as detailed below, that is to say configured to receive the signals of the aforementioned new type (SPT) and extract therefrom the aforementioned time and position information to calculate a (second) time synchronized on GNSS time and, in a particular implementation, also calculate a position of the receiver device.

In a particular implementation, there are a plurality of regenerative devices and a plurality of sink devices.

An advantage of the proposed solution is to provide a time and/or positioning service, with an accuracy of the same order of magnitude as the current GNSS systems, even when the GNSS signals cannot be used by the GNSS receivers (and what whatever the reason: see non-exhaustive list above), because:

• position and time (SPT) signals are not completely independent of GNSS signals, but rather based on them (position and time (SPT) signals contain time information calculated from received GNSS signals and, in a particular implementation, position information of the regenerator device also calculated from received GNSS signals). Thus, the receiver device can calculate a (second) time synchronized with the GNSS time; And
• the position and time signals (SPT) are received by the receiver device with a higher power than the GNSS signals since the regenerator device is embedded on a support located closer to the ground (and therefore to the receiver device) than the GNSS satellites. Thus, the time and/or positioning service that is provided is robust and reliable.

Another advantage of the proposed solution is to provide a time and/or positioning service that can be complementary or alternative to the service of the same nature provided by current GNSS systems.

According to a particular characteristic, the reception module of the GNSS receiver type is configured to also calculate the position of the regenerator device, according to the GNSS signals received.

Thus, full advantage is taken of the GNSS signals received by the regenerator device to calculate the position of the latter.

According to one particular characteristic, said time synchronized with GNSS time comprises a PPS synchronization signal and/or dating information.

According to a particular characteristic, the transmission means are configured to transmit said position and time signal (SPT) on at least two distinct frequencies.

This allows, thanks to the diversity of frequencies, time corrections linked for example to the propagation of waves in the atmosphere (ionosphere, troposphere, etc.).

According to one particular characteristic, the transmission means are configured to transmit said position and time signal (SPT) synchronously with respect to GNSS time and over an entire second of GNSS time.

In this way, the proposed solution benefits from the precision of the GNSS system(s) on which it is based (i.e. whose regenerative device uses the GNSS signals).

According to a particular characteristic, said support is fixed or mobile, on earth, in the atmosphere or in space.

In this way, many implementations can be envisaged to provide position and time signals (SPT) to a maximum of receiver devices.

According to a particular characteristic, said support is a satellite positioned in a first terrestrial orbit having an altitude lower than that of a second terrestrial orbit on which said GNSS satellites are positioned.

Thus, the terrestrial coverage of the position and time signal (SPT) transmitted by the regenerator device is optimized. If the time and/or positioning system comprises a sufficient number of satellites each carrying a regenerative device, worldwide coverage can be obtained to provide position and time signals (SPT) to receiving devices on earth. In addition, the various regenerator devices operate independently of each other, consequently the space segment (that is to say the constellation of satellites carrying the regenerator devices) can be built gradually and opportunistically depending on the satellites launched. The constellation of satellites carrying the regenerative devices may not even be dedicated (each regenerative device is in this case a secondary payload, considered as a “secondary passenger” compared to a main payload of the satellite), thus reducing the cost of the space segment deployment. An intermediate solution can also be envisaged, with one or more dedicated satellites (that is to say whose main payload is a regenerative device) and one or more non-dedicated satellites (that is to say whose ( or one of the secondary payload(s) is a regenerative device).

According to a particular characteristic, the first earth orbit is a low earth orbit (LEO) or a medium earth orbit (MEO).

In this way, the terrestrial coverage of the position and time signal (SPT) transmitted by the regenerator device is further optimized.

In another embodiment of the invention, there is proposed a receiver device belonging to a time and/or positioning system, characterized in that it comprises a first reception module (“SPT receiver”) itself comprising :

• reception means, configured to receive at least one position and time signal (SPT) transmitted by a regenerating device and conveying time information, relating to a first time synchronized on the GNSS time, and position information, relating at a position of the regenerative device;
• processing means, configured to extract the time and position information conveyed by said at least one position and time signal (SPT); And
• calculating means, configured to calculate a second time synchronized with the GNSS time, as a function of the time and position information extracted from said at least one position and time signal (SPT).

As explained above, the receiver device is, with the regenerative device, one of the two associated components in the new and inventive approach on which the proposed solution is based. The proposed solution is therefore based on a receiver that is simple to produce and inexpensive. In addition, the position and time signals (SPT) being received by the receiver device with a higher power than the GNSS signals, it is not necessary to add additional infrastructure on the ground (in particular, no infrastructure expensive in buildings to usually compensate for the fact that GNSS signals cannot be used in "indoor" reception inside these buildings).

According to a particular characteristic, the reception means are configured to receive at least four position and time signals (SPT) each transmitted by a different regenerating device. The processing means are configured to extract time and position information conveyed by each of said at least four position and time signals (SPT). The calculating means are configured to calculate said second time and a position of the receiver device, according to the time and position information extracted from said at least four position and time signals (SPT).

Thus, the receiver device provides both the second time (synchronized to the GNSS time) and the position of the receiver device, even when the GNSS signals cannot be used by the GNSS receivers (for whatever reason: see non-exhaustive list above).

According to a particular characteristic, the second calculated time comprises a synchronization signal PPS (PPS_SPT) and/or dating information.

According to a particular characteristic, the receiver device comprises:

• a local oscillator delivering a clock signal to the first receiving module (“SPT receiver”); And
• means for slaving the local oscillator to at least one frequency reference belonging to the group comprising:
  • a first frequency reference, which is the PPS synchronization signal (PPS_SPT) included in the second calculated time; And
  • a second frequency reference, which is another PPS synchronization signal external to said receiver device.

In this way, in the case where each support carrying a regenerative device is mobile (satellite in LEO orbit for example), the servo-control allows the local oscillator to deliver a clock signal having the time stability required in the first reception module (“SPT receiver”) between two overflight times of a support carrying a regenerative device. The number of supports (satellites in LEO orbit for example) and regenerative devices on board them can thus be greatly reduced and the cost of the infrastructure is therefore minimized. For example, with twenty satellites in LEO orbit and each carrying a regenerative device, it is possible to provide a time service (synchronization) with the assumption of a known position of the receiver device and the servo clock having good stability properties. The provision of the position requires more than twenty satellites because it requires at least four satellites in visibility. A global positioning service is possible with a larger constellation, for example of at least one hundred LEO satellites (the exact number is yet to be determined).

According to a particular characteristic, the receiver device comprises:

• a second reception module, of the GNSS receiver type and configured to receive GNSS signals originating from GNSS satellites of at least one GNSS constellation and to calculate a third time synchronized with the GNSS time and a position of the receiver device, as a function of the GNSS signals receipts; And
• means for deciding at least one first output cue from the receiver device, configured to make a selection between at least one output cue from the first reception module (“SPT receiver”) and at least one output cue from the second module reception of the GNSS receiver type, as a function of at least one selection criterion.

In this way, the time and/or positioning service of the proposed solution is complementary to the service of the same nature provided by current GNSS systems.

According to one particular characteristic, the selection criterion is a function of a comparison between at least one first integrity cue provided by the first reception module ("SPT receiver") and at least one second integrity cue provided by the second GNSS receiver type receiving module.

In this way, the selection is simple to implement.

According to one particular characteristic, said at least one first output cue from the receiver device belongs to the group comprising:

• a PPS synchronization signal;
• at least one dating information;
• at least one position information; And
• a clock signal slaved to GNSS time.

According to a particular characteristic, the decision means are also configured to generate at least one second output cue belonging to the group comprising:

• at least one status information of the receiver device; And
• at least one piece of information indicating a quality of said at least one first output piece of information.

According to a particular characteristic, said slaving means are configured to slave said local oscillator to at least one frequency reference belonging to the group comprising:

• said first frequency reference, which is the PPS synchronization signal (PPS_SPT) comprised in the second calculated time;
• said second frequency reference, which is another PPS synchronization signal (PPS_EXT) external to said receiver device; And
• a third frequency reference, which is a PPS synchronization signal (PPS_GNSS) included in the third calculated time.

In this way, the third calculated time (very precise since synchronized on the GNSS time and calculated by the second reception module of the GNSS receiver type) can also be used to control the local oscillator.

According to a particular characteristic, the receiver device comprises interface means configured to provide a first equipment item, external to said receiver device, with a time and/or positioning service.

Thus, any first piece of equipment (in particular but not exclusively a time server) configured to cooperate with the receiver device can benefit from the time and/or positioning service.

According to one particular characteristic, the receiver device is integrated into a second piece of equipment to supply said second piece of equipment with a time and/or positioning service.

Thus, any second piece of equipment (in particular but not exclusively a time server) integrating the receiver device can benefit from the time and/or positioning service.

In another embodiment of the invention, there is proposed a time server which integrates or cooperates with a receiving device, and which is configured to receive a time and/or positioning service provided by the receiving device and to distribute said time and/or positioning service within a network.

The proposed time server benefits from all the advantages (discussed above) of the receiver device that it integrates or with which it cooperates.

In another embodiment of the invention, there is proposed a method for providing a time and/or positioning service, in which at least one regenerative device performs the following steps:

• reception of GNSS signals from GNSS satellites of at least one GNSS constellation;
• calculation of a time synchronized with the GNSS time, according to the GNSS signals received;
• generation of a position and time signal (SPT) conveying time information, relating to said time synchronized to GNSS time, and position information, relating to a position of the regenerative device; And
• transmission of the position and time signal (SPT).

In another embodiment of the invention, there is proposed a method for providing a time and/or positioning service, in which the at least one receiver device performs the following steps:

• reception of at least one position and time signal (SPT) transmitted by a regenerative device and conveying time information, relating to a first time synchronized to the GNSS time, and position information, relating to a position of the device regenerator;
• processing said at least one position and time signal (SPT) to extract time and position information therefrom; And
• calculation of a second time synchronized with the GNSS time, according to the time and position information extracted from said at least one position and time signal (SPT).

5. LIST OF FIGURES

Other characteristics and advantages of the invention will appear on reading the following description, given by way of indicative and non-limiting example, and the appended drawings, in which:

illustrates a time and positioning system according to a particular embodiment of the invention, comprising in particular a regenerative device on board a LEO satellite and a receiver device;

illustrates a first way of transmitting the position and time signal (SPT signal) generated by the regenerative device;

illustrates a second way of transmitting the position and time signal (SPT signal) generated by the regenerative device;

presents an example of a block diagram of the regenerative device;

presents an example of a block diagram of the receiver device;

illustrates an example of hardware architecture of block 202 (receiverSPT) of FIG. 4;

shows an example of functions performed by block 202 (SPT receiver) of FIG. 4;

illustrates a first example of slaving of a local oscillator within the receiver device, in the case where the local oscillator is an atomic micro-clock;

illustrates a second example of slaving of a local oscillator within the receiver device;

illustrates a time server incorporating a receiver device;

illustrates a time and positioning system according to another particular embodiment of the invention, comprising a time server cooperating with a receiver device;

presents a flowchart of a particular embodiment of the process performed by the regenerative device; And

presents a flowchart of a particular embodiment of the method executed by the receiver device.

6. DETAILED DESCRIPTION

In all the figures of this document, identical elements and steps are designated by the same reference numeral.

6.1 General principle

We now present, in relation to FIG. 1 , a time and positioning system according to a particular embodiment of the invention, comprising in particular:

• at least one regenerative device 1 on board a LEO 6 satellite (low earth orbit) and configured (at least) to perform the following actions (corresponding to the steps referenced 110 to 113 in FIG. 11 ):
  • receive (110) GNSS 4 signals originating from GNSS 3 satellites of at least one GNSS constellation and calculate (111) on the one hand a time synchronized with the GNSS time and on the other hand the position of the regenerator device, according to the GNSS signals received;
  • generate (112) a position and time signal (SPT) 5 different from the GNSS signals 4 and conveying time information, relating to a first time synchronized on the GNSS time (comprising for example a PPS synchronization signal (called by the following “PPS_GNSS”) and/or dating information), and position information, relating to a position of the regenerative device; And
  • transmit (113) the position and time signal (SPT) 5 (in a particular implementation detailed below, this transmission is carried out on at least two distinct frequencies and synchronously with respect to the GNSS time and over an entire second of the GNSS time); And
• at least one receiver device 2 placed on the ground (that is to say on the earth 8) and configured (at least) to perform the following actions (corresponding to the steps referenced 121 to 123 in FIG. 12 ):
  • receive (121) one or more position and time signals (SPT) transmitted by one or more regenerative devices (each position and time signal (SPT) each carrying time information, relating to the first time synchronized to the GNSS time , and position information, relating to the position of the regenerative device which transmitted it);
  • extracting (122), from each position and time signal (SPT), the time and position information; And
  • calculate (123) at least a second time synchronized to the GNSS time (for example also comprising a PPS synchronization signal (hereinafter called “PPS_SPT”) and/or dating information), as a function of the time information and of positions extracted. If the receiver device 2 is configured to receive at least four position and time signals (SPT) transmitted by at least four different regenerative devices, it can also be configured to calculate a position of the receiver device according to the time and position extracted from the at least four position and time (SPT) signals.

In the example of Figure 1, the regenerative device 1 is on board as a secondary load, alongside a main payload 8, on a LEO satellite 6 which is therefore not dedicated to the present solution.

In a variant, the system comprises at least one dedicated LEO satellite (that is to say whose main payload is the regenerator device 1).

In another variant, at least one regenerative device 1 is on board a satellite positioned in a first earth orbit (for example MEO (medium earth orbit)) having an altitude lower than that of a second earth orbit (also of MEO type ) on which the GNSS satellites are positioned.

In another variant, at least one regenerative device 1 is on board a support, other than a satellite, and which is fixed or mobile, on earth, in the atmosphere or in space. All types of mobile supports can be considered: aircraft, balloons, etc.

The receiver device 2 comprises a first reception module, hereinafter called “SPT receiver”, configured to carry out the aforementioned actions: reception (121) of position and time signals (SPT), extraction (122) of time information and position and calculation (123) of a second time synchronized to the GNSS time and of a position of the receiver device.

In a particular implementation detailed below, the receiver device 2 further comprises:

• a second reception module, subsequently called “GNSS receiver”, configured to directly receive the GNSS 4 signals coming from the GNSS 3 satellites and calculate on the one hand a third time synchronized to the GNSS time (comprising for example the synchronization signal PPS_GNSSet /or dating information) and on the other hand the position of the receiver device, according to the GNSS signals received; And
• decision means supplying at least one first output item of information from the receiver device 2 (for example a synchronization signal PPS (hereinafter called “PPS_OUT”), at least one item of dating information, at least one item of position information, a signal clock slaved to GNSS time, etc.). These decision means take advantage of the presence of two different receivers (namely the SPT receiver and the GNSS receiver) within the receiver device 2, to make a selection between at least one output item of information from the SPT receiver and at least one item of information output from the GNSS receiver, as a function of at least one selection criterion. The selection criterion is for example a function of a comparison between at least one first integrity cue provided by the SPT receiver and at least one second integrity cue provided by the GNSS receiver. Optionally, the decision means are also configured to generate at least one second output item of information (for example at least one item of information about the state of the receiver device2, at least one item of information indicating a quality of the first information(s) output(s).

In a particular implementation detailed below, the receiver device 2 further comprises an ultra-stable local oscillator, delivering a clock signal to the SPT receiver, and means for slaving this local oscillator to at least one frequency reference. The slaved oscillator (forming a stable local clock) is preferentially able to maintain a time reference for at least 30 minutes with an accuracy better than 200 ns. As detailed below, the frequency reference is for example chosen from:

• a first frequency reference, which is the synchronization signal PPS_SPT (included in the second time calculated by the receiver SPT); And
• a second frequency reference, which is another synchronization signal PPS (hereinafter denoted PPS-EXT) external to the receiver device and having good stability properties; And
• a third frequency reference, which is the PPS_GNSS synchronization signal (included in the third time calculated by the GNSS receiver).

In a particular implementation, the receiver device 2 is integrated alone in a box. It includes interface means configured to provide another piece of equipment (placed close to the receiver device) with a time and/or positioning service. In another particular implementation, the receiver device 2 is integrated with another piece of equipment to provide it with a time and/or positioning service. In the two aforementioned implementations, “other equipment” means any equipment requiring and/or distributing a time and/or positioning service. As detailed below, it may in particular, but not exclusively, be a time server configured to receive a time and/or positioning service supplied by the receiver device 2 and to distribute this service within a network.

6.2 Examples of c configurations possible of the system

In a first configuration, the proposed time and positioning system offers a GNSS time broadcasting service. The receiver device 2 sees at least one LEO satellite 6 carrying a regenerator device 1. In this configuration, a prerequisite is that the receiver device 2 knows its position: either because it is a fixed receiver device whose position is known, or because the system includes means for carrying out a rough localization of the receiver device. The coarse localization is for example carried out by exploiting the Doppler frequency measurement. Indeed, the use of LEO satellites whose speed is high makes it possible to efficiently exploit the Doppler frequency measurements. It is thus possible to estimate the position to within a few hundred meters over two passages. This principle takes up the concept of location used in the ARGOS and COSPAS/SARSAT systems and the DORIS system (precise positioning of satellites). In the case of a fixed receiver, several measurements over a higher number of passes can improve the position accuracy if necessary.

In a second configuration, the proposed time and positioning system makes it possible to offer a GNSS location and time service for a mobile receiver device 2. The receiver device must be in visibility of at least four LEO 6 satellites, each carrying a regenerative device 1, to determine its position and determine the time with precision. The time will be based on GNSS time.

Depending on the type of constellation of LEO satellites (each embedding a regenerative device 1) and the associated coverage, one and/or the other of the first and second configurations is (are) possible. For example, a first phase of implementation is to provide a secure time service usable by fixed time servers (first configuration with for example 20 LEO satellites) then to provide a secure time service for mobile servers and a location service that could operate indoors through the use of more penetrating UHF signals (compared to L-band GNSS signals from MEO satellites at 20,000 km). In the second configuration, a constellation of the order of 200 LEO satellites, for altitudes between 600 km and 800 km, is for example possible because a minimum of four LEO satellites are required in visibility of the receiver device 2 with a diversity of orbital planes.

6.3 Example of d regenerative device details

Figures 2a and 2b illustrate two ways of transmitting the position and time signal ( SPT ) generated by the regenerator device 1 on board a LEO 6 satellite. It is assumed that the LEO 6 satellite is of the "CUBESAT" type and includes:

• a platform 61, 62 enabling the satellite to operate (it notably comprises the following elements: mechanical structure, on-board computer (OBC), energy production and storage system (EPS), telecommunications system (antennas, transmitter, receiver …), etc.);
• a main payload 63 generating and transmitting a mission RF signal 68 on a frequency F3 with an antenna referenced 65; And
• the regenerative device 1 which constitutes a secondary payload and which generates and transmits a position and time signal (SPT) 69a/69b on two frequencies with two antennas.

In the first example shown in Figure 2a, the function of generating the position and time signal (SPT) 69a/69b by the regenerative device 1 is entirely independent and based on the regenerative device's own RF front-end. The regenerator device 1 uses for example two authorized transmission frequencies, F1 and F2, which can be chosen in the free ISM bands provided that they offer sufficient characteristics of transmission power and usable band with a minimum of 1 MHz. . The two frequencies F1 and F2 are emitted by two antennas referenced 64a and 64b.

In the second example illustrated in FIG. 2b, the position and time signal (SPT) generation function by the regenerator device 1 uses a front-end available on the satellite platform. The position and time signal (SPT) 69a/69b generated by the regenerator device 1 is transmitted on two frequencies F1 and F3. For the frequency F3, the position and time signal (SPT) 69b is superimposed (thanks to the element 611) on the mission RF signal 68 available on the downlink and having satisfactory characteristics in terms of bandwidth (as per generation 4 Argos signals from the constellation of 20 Argos nano-satellites under development). The resulting signal 610 is transmitted on the frequency F3 with the antenna referenced 65.

The position and time signal (SPT) is transmitted on two separate frequencies to transmit precise time to the ground (compensation for ionospheric effects by exploiting frequency diversity).

Figure 3 shows an example of a block diagram of the regenerator device.

Block 101 is a broadband reception antenna covering all GNSS frequencies (L1/E1, L5/E5, L2, G1/G2, E6, B1, B3).

Block 102 is an RF head for receiving GNSS signals for different constellations (GPS, GALILEO, BEIDOU, GLONASS, etc.). It incorporates filters and a low noise amplifier (LNA).

Block 103 performs a function of transforming the RF signal into intermediate frequency (IF) or baseband (BdB).

Block 104 performs an analog/digital conversion function of RF signals at intermediate frequency or at baseband. This function can include several separate but perfectly synchronized scanning channels.

Block 106 performs a GNSS processing function comprising: demodulation of GNSS signals, frequency and time measurements relative to the GNSS reference frame, production of a PPS signal (PPS_GNSS), calculation of the current position of the regenerator device instant (“snapshot”).

Block 107 performs a navigation function including calculating the precise position of the regenerative device. It includes an orbit model and a navigation filter.

Block 108 performs a message generation function with the time and position information computed by blocks 106 and 107.

Block 109 performs a function of generating a position and time signal (SPT), at baseband or at intermediate frequency, from the messages generated by block 108.

Block 112 performs a digital/analog conversion function of the position and time signal (SPT) to be transmitted.

Block 113 receives the position and time signal (SPT) after its conversion by block 112 and performs an RF frequency transposition function for transmission, as well as an amplification function of the RF signal resulting from the transposition .

Block 114 is a transmit antenna for the position and time signal (SPT) generated by block 113.

Block 105 delivers an ultra-stable local clock signal to blocks 102, 103 and 104, for receiving GNSS signals.

Block 111 provides an ultra-stable local clock signal to block 109, for transmitting the position and time signal (SPT).

Block 110 performs a function of calculating local clock drift parameters with respect to the reference GNSS clock. Block 110 receives the outputs of blocks 106 and 111. The output of block 110 is provided to block 108.

Blocks 101 to 114 can be produced in a material (hardware) and/or software (software) manner, either on a reprogrammable calculation machine (PC computer, DSP processor or microcontroller) executing a program comprising a sequence of instructions, or on a dedicated calculation machine (for example a set of logic gates such as an FPGA or an ASIC, or any other hardware module).

The characteristics of the RF position and time signal (SPT), transmitted by block 114, are for example the following:

• the two carrier frequencies selected to transmit (each) the position and time signal (SPT) are in a free or unconstrained band;
• the position and time signal (SPT) is transmitted simultaneously on the two carrier frequencies sufficiently separated from each other to allow time corrections related to the propagation of waves in the atmosphere (ionosphere, troposphere, etc.);
• the modulation of the position and time signal (SPT) is of the BPSK or QPSK type;
• in a preferred mode, the position and time signal (SPT) is frequency spread via a CDMA type spreading code (Code Division Multiple Access) making it possible to separate several sources transmitting at the same frequency. In a simplified mode, the position and time signal (SPT) is modulated without spreading code, which does not make it possible to separate the position and time signals (SPT) transmitted by several regenerative devices in the case where the frequencies are identical (collisions); the separation of the sources is then carried out thanks to the differences in Doppler frequency between them;
• in the case of the use of a spreading code, each regenerative device generates a position and time signal (SPT) with its own CDMA code allowing it to be uniquely identified;
• the CDMA codes used are mutually orthogonal to minimize interference between the position and time signals (SPT) transmitted simultaneously at the same frequency by several regenerative devices in visibility of the receiver device;
• the position and time signals (SPT) are transmitted synchronously with respect to GNSS time and on the whole second of GNSS time;
• the messages carried by the position and time signal (SPT) contain at least the GNSS time information, the ephemeris of the satellite carrying the regenerator device, the clock correction parameters, the transmission time, the parameters of status of the position and time signal (SPT) (reliable, unreliable, in maintenance...).

6.4 Example of d receiving device details

FIG. 4 presents an example block diagram of the receiver device.

Block 201 (also called above “GNSS receiver”) performs a function of receiving and processing GNSS signals, with production for example of the PPS_GNSS signal (synchronization reference based on the whole second of the GNSS signal), PVT information (Position, Velocity and Time), raw measurements, health information, etc. Block 201 has, in a preferential mode, algorithms reducing the sensitivity to disturbances of electromagnetic origin and integrity measurement algorithms making it possible to evaluate the quality and reliability of the data (i.e. time, position and speed) produced. The GNSS receiver can be a commercial receiver or else a software receiver operating on software radio type electronics and integrated on the same processing unit as the SPT receiver (block 202).

Block 202 (also called above “SPT receiver”) performs a function of receiving and processing position and time signals (SPT), with production for example of the PPS_SPT signal, PVT information (Position, Velocity and Time) , raw metrics, health information, and more.

Figure 5 illustrates an example hardware architecture of block 202 (SPT receiver). It comprises two antennas 2021, two amplifiers (LNA) 51, an RF block 52 and a reprogrammable computing machine type block (for example in FPGA/CPU (SoC) form).

Figure 6 shows an example of functions performed by block 202 (SPT receiver).

Block 2021 is a receiving antenna compatible with position and time (SPT) RF signals emitted by regenerative devices.

Block 2022 is an RF head for receiving position and time (SPT) signals. It incorporates filters and a low noise amplifier (LNA).

Block 2023 performs a function of transforming the RF signal into intermediate frequency (IF) or baseband (BdB).

Block 2024 performs an analog/digital conversion function of RF signals at intermediate frequency or at baseband.

Block 2025 performs a function of acquisition and demodulation of position and time signals (SPT): measurement of the Doppler frequency, measurement of the Receiver/Transmitter pseudo-distance, extraction of SPT messages (messages contained in the signals of position and time (SPT)), etc.

Block 2026 performs a function of calculating the speed and time position of the SPT receiver. In particular, it provides the PPS_SPT signal (PPS derived from the position and time signal (SPT) after estimating the clock bias between the receiver and the transmitter).

Block 2027 performs an external communication function.

Block 2028 provides an ultra-stable local clock signal.

We now return to the description of Figure 4.

Block 203 (also called above "local oscillator") delivers an ultra-stable local clock signal (PPS_OL signal), locked to a frequency reference (which is one of the PPS_SPT, PPS_GNSS and PPS_EXT signals discussed above) thanks to block 204. The local oscillator constitutes the frequency reference of the synchronization and positioning function (block 205) when no other frequency reference is available. The local oscillator is tuned to a frequency f _OL and must have good stability and phase noise characteristics. In a preferred implementation, this frequency takes the value 10 MHz, but is not limited to this value. The local oscillator is frequency controllable via the application of a supply voltage supplied by an external function. The frequency of the local oscillator can be controlled via an analog voltage calculated by block 204. This analog voltage is directly calculated by a feedback loop of the local oscillator on a frequency reference that can be extracted from the GNSS signal or from the receiver SPT, or even a frequency reference external to the receiver device and having satisfactory short and medium term stability properties.

FIG. 7 illustrates a first example of slaving of a local oscillator within the receiver device, in the case where the local oscillator is an atomic micro-clock. The same principle can be applied to any other type of oscillator (OCXO for example) provided that its intrinsic frequency stability performance is good enough to maintain time with an accuracy of less than 200 ns over 30 minutes without external aid.

This system makes it possible to slave the synchronization signal generated by the micro-clock, named PPS_out, to an incoming synchronization signal, named PPS_in. This slaving consists in canceling the time interval present between the two rising edges of the signals PPS_in and PPS_out.

Operation is as follows. It requires the nesting of two servo loops:

- first control loop: A radiofrequency signal (denoted “RF signal”) (typically 10 MHz) is generated by a local oscillator (72). This signal is multiplied in a phase-locked loop (77) and then compared (78) to the resonance frequency of the hyperfine transition of an alkaline atom (71). The result of this comparison is applied to the "command" input of the local oscillator (72) so as to control its frequency. It should be noted that if the multiplier coefficient (77) is modified (N increased or decreased), the slaving leads to a variation in the frequency of the local oscillator. It is this function that will be used later;

- second control loop: The PPS_out signal is generated by a counter (73) from the radio frequency signal. The time interval present between the two rising edges of the signals PPS_in and PPS_out is calculated by a subtractor (74). (this interval is called φ err.). The time interval is transformed into a frequency correction by a corrector (75) (typically a proportional integrator). A switch (76) makes it possible to apply or not the correction to the multiplier coefficient of the phase-locked loop. If the switch (76) is closed, a correction is applied to the multiplier. The first control loop being activated, this correction varies the frequency of the local oscillator (72), which leads to a modification of the PPS_out signal (the modification consists in increasing or reducing the duration between two pulses of this PPS_out signal) . The time interval present between the two rising edges of the signals PPS_in and PPS_out is then reduced, and tends towards zero after a few operating times. The PPS_out signal is then synchronized on the PPS_in signal. If the switch (76) is open, then the servo-control is cut off and the PPS_out signal is no longer slaved to the PPS_in signal.

In general, this system makes it possible to compensate for a temporary unavailability of the PPS_in signal. Indeed, as long as a PPS_in signal is available, the PPS_out signal is slaved to it (it copies it). When the PPS_in signal is temporarily unavailable, the PPS_out signal continues to provide a signal whose quality is that of the atomic frequency reference.

FIG. 8 illustrates a second example of slaving of a local oscillator within the receiver device. The receiver device comprises elements referenced 81a to 87, which are detailed below.

Element 81a: Ultra stable oscillator controlled by an accurate and reliable frequency reference. The oscillator is controlled via a voltage command 88 generated by element 86.

Element 81b: Counter of clock periods generated by oscillator 81a making it possible to produce a signal in the form of a pulse of short duration every second (PPS_OL signal).

Element 82a: Reliable and stable external frequency reference that can come from an atomic clock type source, rubidium or any other frequency source with good stability properties and GNSS time-controlled.

Element 82b: Counter of clock periods of element 82a used to generate a signal in the form of a pulse of short duration every second (signal PPS_EXT).

Element 83a: Frequency reference constructed from GNSS signal.

Element 83b: Counter slaved to the GNSS frequency reference 83a and making it possible to generate a pulse of short duration every second (PPS_GNSS signal). The rising edge of this pulse corresponds to a whole second of GNSS time. From an implementation point of view, this counter is integrated directly into the global GNSS reception module.

Element 84a: Frequency reference coming from the exploitation of the SPT signal carrying the GNSS time information.

Element 84b: Counter slaved to the frequency reference resulting from the exploitation of the SPT signal, and making it possible to generate a pulse of short duration every second (PPS_SPT signal). The rising edge of this pulse corresponds to a whole second very close to the whole second of GNSS time. From an implementation point of view, this counter is integrated directly into the SPT signal reception module as in the case of the GNSS receiver.

Element 85: This module is used to construct a comparison signal between the PPS_EXT, PPS_GNSS and PPS_SPT signals generated by the various frequency references and the PPS_OL signal generated by the local oscillator.

Element 86: This module exploits the comparison signal generated by element 85, in order to construct the control signal 88 for the control of the local oscillator. The comparison information on several signal sources makes it possible to monitor possible alterations of the signals (GNSS signals and SPT signals in particular) received. The module 86 also delivers a set of parameters, denoted PARAM_OUT, describing the behavior of the local clock 81a of the receiver device 2. These parameters are determined for a certain comparison time between the GNSS clocks and the local clock of the regenerator device 1 (embedded on satellite 6). These parameters are likely to be integrated into the messages transmitted via the SPT signals (position and time signal) 5, to enable the receiver device 2 to correct biases or clock drifts of the regenerator device 1 (onboard the satellite 6) relative to GNSS satellite clocks.

Element 87: This module is used to select the PPS_OUT signal to be output. The selector is controlled by the integrity analysis block of the various PPS signals produced and/or used (block referenced 205 in FIG. 4).

In the case where the PPS_SPT, PPS_GNSS and PPS_EXT signals are not available or not intact (detection via the block referenced 205 in FIG. 4), only the PPS_OL signal from the local oscillator is selected at output to produce the PPS_OUT signal .

We now return to the description of Figure 4.

Block 204 performs a function making it possible to determine the clock parameters (bias, drift, etc.) for the aforementioned servo-control. This function can take as input one or more of the aforementioned PPS signals: PPS_OL, PPS_SPT, PPS_GNSS and PPS_EXT. In other words, block 204 evaluates the frequency correction to be applied to the local oscillator (block 203) by comparing the PPS signals produced by the local oscillator and the frequency reference (PPS_GNSS, PPS_SPT, PPS_EXT). The use of an ultra-stable external frequency reference (PPS_EXT) is possible via a specific interface. The clock correction parameters are for example continuously updated and are in a preferential configuration updated according to the specific properties of the oscillator (such as aging for example) and external constraints (such as the temperature For example). Filtering algorithms are applied to allow better long-term stability.

Block 205 performs a function having a decision algorithm for selecting reliable time information (several selections are possible, among for example: only the information provided by block 201 (GNSS receiver), only the information provided by the block 202 (SPT receiver), both the information provided by block 201 and that provided by block 202, only the information provided by block 203 (local clock). ) uses an algorithm to select the data that can be used for the timing, synchronization and position function. The main outputs of block 205 are for example: the selected PPS signal (PPS_OUT), timing information, position information, status information of the receiver device, information indicating the quality of time and position measurements, a clock signal slaved to GNSS time, etc.

Block 206 performs a communication function with the outside (that is to say a communication interface function), for example with a time server having a compatible interface. It makes it possible to interface the receiver device with external equipment which can be a time server or equipment requiring synchronization on a known and stable reference. The interface is for example made up of a bus-type physical part for data exchange and a discrete interface for transmitting the generated PPS_OUT signal.

6.5 Example of c of use with a time server

FIG. 9 illustrates a time server integrating a receiver device. In this embodiment, the receiver device 2 described above is integrated into a time server for time distribution applications and a synchronization signal. The time server therefore includes:

• the receiver device 2 for the generation of time information (dating, PPS, frequency reference in a preferential mode set at 10 MHz). It has decision capability to provide a reliable PPS_OUT signal and 10 MHz clock signal; And
• a time server module 901 whose function consists in broadcasting (via interfaces 902 and 903) the time information in a private network via the dedicated protocols NTP, PTP. He is also responsible for checking the validity of the time information provided by different sources such as the GNSS receiver, the SPT receiver, etc.) to produce PPS_OUT timing signals, 10MHz frequency or messages in different formats (NMEA, IRIG- B, NTP, PTP…). This module includes its own processing core (CPU/FPGA) independent of the receiver device 2.

FIG. 10 illustrates a time and positioning system according to another particular embodiment of the invention, comprising a time server 100 cooperating with (and therefore not integrating) a receiver device 2.

As in the embodiment of Figure 9, it is a question of proposing a system capable of providing a synchronization service making it possible to offer continuity of service when the GNSS signals (GPS, GALILEO, etc.) cannot be exploited (strong masking, indoor, jamming and decoy…). It is therefore a question of developing a system complementary to the GNSS systems for the supply of a secure reference time. The receiver device 2 is added upstream of the time server 100 in order to secure the supply of a time to a critical system.

The receiver device 2 operates for example nominally in a mode of reception of GNSS signals, but in the event of disturbance (masking or radio interference for example) switches to another mode (“SPT mode”) in which only the position and (SPT) emitted by the regenerator device 1 (embedded for example on a LEO satellite, as described above) are exploited to maintain the time with an accuracy of the order of 100 ns of precision, that is an accuracy of the same order of magnitude than GNSS time. When the GNSS signals and the SPT signals are simultaneously unavailable, the local time is used (provided by the local slave oscillator) to provide the synchronization information. The synchronization precision is dependent on the stability of the local oscillator.

The receiver device 2 can operate inside a building because the power of the position and time signals (SPT) received from a LEO satellite is much greater than the GNSS signals and the frequency in the UHF band of the Position and time (SPT) signals are much more penetrating than GNSS signals. In some cases (this may depend on the configuration of the building), a simple patch antenna placed inside a room is sufficient. There is then no need to set up an antenna on the roof and incur infrastructure costs in the building.

The supply of the receiver device 2 can be backed by a license. This license makes it possible to secure the service provided, thanks to an authentication key distributed via a wired or cellular network.

The regenerative devices 1 on board the LEO satellites can operate without needing to communicate with the other payloads of the constellation. This unitary independence of the regenerative devices 1 vis-à-vis the other elements of the space segment makes it possible to gradually build the constellation while being, if necessary, a secondary passenger of launched nano-satellites.

Claims (22)

Regenerative device (1) belonging to a time and/or positioning system, characterized in that it is embarked on a support (6) located closer to the earth than the GNSS satellites (3) and in that He understands:

• a reception module (101 to 107), of the GNSS receiver type and configured to receive GNSS signals originating from GNSS satellites of at least one GNSS constellation and to calculate a time synchronized with the GNSS time, as a function of the GNSS signals received;
• means (108 to 111) for generating a position and time signal (SPT) different from said GNSS signals and conveying time information, relating to said time synchronized to GNSS time, and position information, relating to a position of the regenerative device; And
• means (112 to 114) for transmitting the position and time signal (SPT).

Regenerator device according to Claim 1, characterized in that the reception module of the GNSS receiver type is configured to also calculate the position of the regenerator device, as a function of the GNSS signals received. Regenerative device according to any one of claims 1 and 2, characterized in that said time synchronized to GNSS time comprises a PPS synchronization signal and/or dating information. Regenerative device according to any one of Claims 1 to 3, characterized in that the transmission means are configured to transmit the said position and time signal (SPT) on at least two distinct frequencies. Regenerative device according to any one of Claims 1 to 4, characterized in that the transmission means are configured to transmit the said position and time signal (SPT) synchronously with respect to GNSS time and over an entire second of the time GNSS. Regenerative device according to any one of Claims 1 to 5, characterized in that the said support is fixed or mobile, on earth, in the atmosphere or in space. Regenerative device according to any one of Claims 1 to 5, characterized in that the said support is a satellite positioned in a first earth orbit having an altitude lower than that of a second earth orbit on which the said GNSS satellites are positioned. Regenerative device according to claim 7, characterized in that the first earth orbit is a low earth orbit (LEO) or a medium earth orbit (MEO). Receiver device (2) belonging to a time and/or positioning system, characterized in that it comprises a first reception module (202) itself comprising:

• reception means (2021, 2022), configured to receive at least one position and time signal (SPT) transmitted by a regenerating device and conveying time information, relating to a first time synchronized to the GNSS time, and position information, relating to a position of the regenerative device;
• processing means (2023 to 2025), configured to extract the time and position information conveyed by said at least one position and time signal (SPT); And
• calculating means (2026), configured to calculate a second time synchronized with the GNSS time, as a function of the time and position information extracted from said at least one position and time signal (SPT).

Receiver device according to Claim 9, characterized in that the reception means are configured to receive at least four position and time signals (SPT) each transmitted by a different regenerating device,
in that the processing means are configured to extract time and position information conveyed by each of said at least four position and time signals (SPT),
and in that the calculating means are configured to calculate said second time and a position of the receiver device, as a function of the time and position information extracted from the said at least four position and time signals (SPT). Receiver device according to either of Claims 9 and 10, characterized in that the second calculated time comprises a PPS synchronization signal (PPS_SPT) and/or dating information. Receiver device according to Claim 11, characterized in that it comprises:

• a local oscillator (203) delivering a clock signal to the first reception module (202); And
• means (85, 86) for slaving the local oscillator to at least one frequency reference belonging to the group comprising:
  • a first frequency reference, which is the PPS synchronization signal (PPS_SPT) included in the second calculated time; And
  • a second frequency reference, which is another PPS synchronization signal external to said receiver device.

Receiver device according to any one of Claims 9 to 12, characterized in that it comprises:

• a second reception module (201), of the GNSS receiver type and configured to receive GNSS signals originating from GNSS satellites (3) of at least one GNSS constellation and to calculate a third time synchronized with the GNSS time and a position of the receiver device , depending on the received GNSS signals; And
• means (205) for deciding at least one first output cue from the receiver device, configured to make a selection between at least one output cue from the first reception module (“receiver SPT”) and at least one output cue of the second reception module of GNSS receiver type, as a function of at least one selection criterion.

Receiver device according to Claim 13, characterized in that the selection criterion is a function of a comparison between at least one first integrity item of information supplied by the first reception module (“SPT receiver”) and at least one second item of integrity information. integrity provided by the second reception module of the GNSS receiver type. Receiver device according to either of Claims 13 and 14, characterized in that the said at least one first output cue from the receiver device belongs to the group comprising:

• a PPS synchronization signal;
• at least one dating information;
• at least one position information; And
• a clock signal slaved to GNSS time.

Receiver device according to any one of Claims 13 to 15, characterized in that the decision means are also configured to generate at least one second output cue belonging to the group comprising:

• at least one piece of receiver device status information; And
• at least one piece of information indicating a quality of said at least one first output piece of information.

Receiver device according to Claim 12 and any one of Claims 13 to 16, characterized in that the said slaving means are configured to slave the said local oscillator to at least one frequency reference belonging to the group comprising:

• said first frequency reference, which is the PPS synchronization signal (PPS_SPT) comprised in the second calculated time;
• said second frequency reference, which is another PPS synchronization signal (PPS_EXT) external to said receiver device; And
• a third frequency reference, which is a PPS synchronization signal (PPS_GNSS) included in the third calculated time.

Receiver device according to any one of Claims 9 to 17, characterized in that it comprises interface means (206) configured to provide a first equipment item (100), external to said receiver device, with a time service and/or or positioning. Receiver device according to any one of Claims 9 to 17, characterized in that it is integrated into a second piece of equipment (90) to supply said second piece of equipment with a time and/or positioning service. Time server (90, 100), characterized in that it integrates or cooperates with a receiver device (2) according to any one of claims 9 to 17, said time server being configured to receive a time service and/ or positioning provided by the receiving device and distributing said time and/or positioning service within a network. Method for providing a time and/or positioning service, characterized in that at least one regenerative device (1) performs the following steps:

• receiving (110) GNSS signals from GNSS satellites of at least one GNSS constellation;
• calculating (110) a time synchronized to the GNSS time, based on the received GNSS signals;
• generation (112) of a position and time signal (SPT) conveying time information, relating to said time synchronized to the GNSS time, and position information, relating to a position of the regenerative device; And
• transmission (113) of the position and time signal (SPT).

Method for providing a time and/or positioning service, characterized in that at least one receiver device (2) performs the following steps:

• reception (121) of at least one position and time signal (SPT) transmitted by a regenerating device and conveying time information, relating to a first time synchronized to the GNSS time, and position information, relating to a position of the regenerative device;
• processing (122) said at least one position and time signal (SPT) to extract the time and position information therefrom; And
• calculation (123) of a second time synchronized with the GNSS time, according to the time and position information extracted from said at least one position and time signal (SPT).