FR3075356A1 - NAVIGATION SYSTEM SUITABLE FOR IMPLEMENTING FUSION OR CONSOLIDATION TREATMENT - Google Patents

Abstract

 The invention relates to a navigation system comprising an inertial system (4, 4a) and a computer (6) remote from the inertial system (4, 4a), in which:  • the inertial system (4, 4a) is configured to:  ○ generate first inertial data,  ○ time stamping the first inertial data in a first time scale, using at least one dating signal in the first time scale,  ○ transmit the first time-stamped inertial data to the computer (6),  • the computer (6) is configured to:  ○ receive first additional data previously generated by a third-party device (2), and also time-stamped in the first time scale,  ○ merge and / or consolidate the first time-stamped inertial data with the first time-stamped additional data, so as to generate first navigation data.

Description

FIELD OF THE INVENTION

The present invention relates to the field of navigation systems suitable for implementing a fusion or consolidation processing on the basis of data emanating from an inertial system and from another device.

STATE OF THE ART

The use of inertial systems in a carrier such as an aircraft is very conventional today. These inertial systems use inertial sensors, in particular accelerometers and gyros (gyrometers or gyroscopes) to measure accelerations and angular speeds of rotation. They provide inertial data depending on these measurements useful for navigation. For example, the development of the position and the speed of the carrier is obtained by integrating a fundamental equation of the dynamics of the carrier.

These inertial sensors have low measurement errors. However, the integration of these measures leads to the appearance of a growing error in time in the navigation information.

Rather than using very high performance and therefore expensive inertial sensors, another solution for limiting the drift of an inertial system consists in implementing fusion algorithms - for example of hybridization - with additional data provided. by another device, such as a satellite positioning device comprising at least one GNSS receiver.

A GNSS receiver generates, from radio frequency signals emitted by the satellites, position and speed data with short-term noise, but with absolute precision that does not degrade over time. The continuity of the information provided by these radiofrequency signals is however not acquired for various reasons (interference, masking of the satellites, etc.).

Hybridization between the inertial system and the satellite positioning device is carried out using a computer, generally using a Kalman filter, which takes as input the inertial data supplied by the inertial system and the navigation data by satellite provided by the GNSS receiver, and combines the advantage of short-term absolute precision of inertia and long-term absolute precision of GNSS.

The inertial system, the GNSS receiver and the computer implementing hybridization can be grouped together in a single box so as to form a monolithic navigation system. However, such a monolithic system is expensive.

Consequently, it is more advantageous that the inertial system, the GNSS receiver and the computer are not grouped together in the same housing so as to form a modular navigation system.

In this way, a navigation system already on board a carrier comprising only an inertial system can be transformed into a hybrid inertial / satellite navigation system by a simple addition of the satellite positioning device and the computer implementing the hybridization, without the need to replace the inertial system preexisting in the carrier.

Such modular systems also offer flexibility of integration in a carrier: its three components can thus be offset relative to each other within the aircraft and connected to each other by links adapted to transport data.

The use of such modular systems, however, reveals a new problem: that of the temporal dating of inertial and satellite navigation data supplied to the computer for hybridization.

To this dating problem is added the fact that, when the computer is offset from the inertial system, the inertial navigation data generated by the inertial system reach the computer with a first transmission delay. Identically, when the computer is offset from the satellite positioning device, the satellite navigation data generated by the satellite positioning device arrives at the computer with a second transmission delay (different from the first delay).

To synchronize the data to be hybridized while compensating for these delays, a navigation system has been proposed where the computer dates the reception of the two types of navigation data it receives, and takes into account the errors induced by the transmission time. of these data by the increase in measurement uncertainties.

However, these additional treatments supported by the computer are complex and degrade the performance of the computer.

STATEMENT OF THE INVENTION

An object of the invention is to simplify, in a modular navigation system, the processing operations implemented by a computer based on the one hand on inertial data supplied by an inertial system and on the other hand on additional data supplied by another device.

It is therefore proposed, according to a first aspect of the invention, a navigation system comprising a first inertial system and a remote computer with respect to the first inertial system, in which:

• the first inertial system is configured to:

o generate first inertial data, o time stamp the first inertial data in a first time scale, using at least one dating signal in the first time scale, o transmit the first inertial data time-stamped to the computer, • the computer is configured for:

o receive first additional data previously generated by a third party device, and also time-stamped in the first time scale, o merge and / or consolidate the first time-stamped inertial data with the first time-stamped additional data, so as to generate first navigation data .

In the proposed system, the data to be consolidated or merged are dated in the same time scale before being received by the computer. The remote calculator can then manipulate this data without the need to date its receipt, and without adding calculation uncertainty linked to the delay. The computer therefore benefits from all the advantages provided by its remote nature in relation to the inertial system and / or to the device providing the additional data, without however degrading the accuracy of the calculations implemented by this computer or requiring a specific dating mechanism.

The system according to the first aspect of the invention may also include the following characteristics, taken alone or in combination when technically possible.

The first additional data may have been time-stamped by the third-party device in the first time scale, and the computer can be configured to receive directly from the third-party device the first additional data time-stamped in the first time scale.

The first additional data may have been time-stamped by the third-party device in the first time scale, and the first inertial system may be configured to:

• receive additional data time-stamped by the third-party device in the first time scale, and • transmit to the computer the first additional data time-stamped in the first time scale.

The first additional data may have been time-stamped by the third-party device in a second time scale different from the first time scale, in which case:

• the dating signal in the second time scale is supplied to the inertial system by the third-party device, • the first inertial system is configured to:

o receive additional data time-stamped by the third-party device in a second time scale, o convert the additional data received into the first additional data time-stamped in the first time scale, using the date signal in the first time scale and of the dating signal in the second time scale, o transmit to the computer the first additional time-stamped data in the first time scale.

The first time scale can be coordinated universal time.

The third-party device can be a satellite positioning device or an odometer.

The dating signal can comprise a digital signal carrying at least one date expressed in the first time scale, and an analog signal comprising at least one pulse synchronized in time with a date transported by the digital signal.

The system can also include a second inertial system configured to:

• generate second inertial data, • time stamp the second inertial data in the first time scale, using at least one dating signal in the first time scale, • transmit the second inertial data time stamped to the computer, and the computer can also be configured to:

• receive second additional data previously generated by a third-party device and also time-stamped in the first time scale, • merge and / or consolidate the second time-stamped inertial data with the second time-stamped additional data, so as to generate second navigation data, • consolidate the first navigation data with the second navigation data.

According to a second aspect of the invention, there is also proposed a navigation method comprising steps of:

• generation of first inertial data by a first inertial system, • time stamping of the first inertial data in a first time scale, using at least one dating signal in the first time scale, • transmission of time stamped inertial data to a remote computer with respect to the inertial system, • reception by the computer of first additional data previously generated by a third-party device and moreover time-stamped in the first time scale, • fusion and / or consolidation by the computer of the first inertial data with the additional data, so as to generate first navigation data.

This method can also comprise steps of:

• generation of second inertial data by a second inertial system, • time stamping of the second inertial data in the first time scale, using at least one dating signal in the first time scale, • transmission of the second inertial data time stamped in the computer, • reception by the computer of second additional data previously generated by a third party device and also time stamped in the first time scale, • fusion and / or consolidation by the computer of the second inertial data with the second additional data, so to generate second navigation data, • consolidation by the computer of the first navigation data with the second navigation data.

DESCRIPTION OF THE FIGURES

Other characteristics, objects and advantages of the invention will emerge from the description which follows, which is purely illustrative and not limiting, and which should be read with reference to the appended drawings in which:

• Figure 1 schematically illustrates a navigation system according to a first embodiment of the invention;

• Figure 2 is a flow diagram of steps of a navigation process implemented by the device according to Figure 1;

• Figure 3 schematically illustrates a navigation system according to a second embodiment of the invention;

• Figure 4 schematically illustrates a navigation system according to a third embodiment of the invention.

• Figure 5 schematically illustrates a navigation system according to a fourth embodiment of the invention.

In all of the figures, similar elements bear identical references.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIG. 1, a navigation system 1 comprises a device 2, an inertial system 4 and a computer 6.

The device 2 is for example a satellite positioning device 2.

The satellite positioning device 2 is typically a GNSS receiver or else a set of several GNSS receivers (for example two receivers). FIG. 1 shows the satellite positioning device 2 as a single GNSS receiver and components internal to this receiver, it being understood that these components are present in each other possible receiver of the satellite positioning device.

The satellite positioning device 2 comprises at least one antenna 8 configured to receive radio navigation signals transmitted by at least one constellation of satellites S.

The satellite positioning device 2 also comprises a processing module 10 capable, from the signals of at least 4 satellites, of calculating the position and the speed of the carrier and of synchronizing with the timescale of the satellite system. , then generally on the UTC universal time scale. The processing module is for example in accordance with the document “CNES, EGNOS Guide for the use of application developers” ED 2.0, 15/12/2011.

The satellite positioning device 2 comprises an output interface for transmitting dating signals generated by the processing module 10.

The output interface includes an analog output 12 on which the analog dating signal can be transmitted, and a digital output 14 on which the digital dating signal can be transmitted.

The satellite positioning device 2 is configured to generate satellite navigation data, and this on the basis of the radio navigation signals picked up by its antenna (s) 8.

The satellite positioning device 2 includes an output 16 via which the satellite navigation data can be transmitted to other equipment.

The outputs 14 and 16 can be one and the same output or can be separate.

Furthermore, the inertial system 4 comprises at least one inertial sensor 18, typically three accelerometers and / or three gyros. Each gyro is a gyrometer or a gyroscope.

The inertial system 4 also comprises a data processing module 20 configured to apply processing operations to data measured by each inertial sensor and generate more or less elaborate inertial data on their basis (compensated increments, or navigation data). The data processing module 20 typically comprises at least one calculation unit (for example a processor).

The inertial system 4 also includes an output 22 via which data generated by the processing module 20 can be transmitted to the computer 6.

The inertial system 4 further comprises an input interface intended to receive at least one dating signal in a time scale. The input interface can for example include an analog input 24 and / or a digital input 26.

The inertial system 4 also comprises a time stamping module 28 configured to time stamp the inertial data generated by the processing unit 20, and this in the external timescale received via the analog 24 and digital 26 inputs.

The inertial system 4 can comprise at least one device of type 1RS ("Inertial Reference System"), for example two.

Alternatively, or as a complement, the inertial system 4 can comprise at least one device of the AHRS type (“Attitude and Heading Reference System”). In this case, the inertial sensors are typically accelerometers and gyros of poorer performance.

The computer 6 is a remote device with respect to the satellite positioning device 2 and / or with respect to the inertial system 4.

By convention, two so-called "remote" devices, one in relation to the other in the present text, means that the two devices in question are not assembled in the same case, but that they have respective respective cases.

The computer 6 comprises a first input 30 and a second input 32 for receiving navigation data, and at least one calculation unit 34 configured to apply merging and / or consolidation processing on the basis of the data received via the inputs 30 , 32 of the computer 6.

The computer 6 also includes an output 36 via which data calculated by the processor can be delivered to another device.

In the navigation system 1, the satellite positioning device 2, the inertial system 4 and the computer 6 are interconnected in the following manner.

The navigation system 1 comprises at least one link for connecting the output interface of the satellite positioning device 2 to the input interface of the inertial system 4. Typically, an analog link 38 connects the analog output 12 of the device satellite positioning 2 at the analog input 24 of the inertial system 4, and a digital link connects the digital output 14 of the satellite positioning device 2 to the digital input 26 of the inertial system 4.

The navigation system 1 also comprises a digital link 42 connecting the digital output 16 of the satellite positioning device 2 to the digital input 30 of the computer 6.

The navigation system 1 also comprises a digital link 44 connecting the digital output 22 of the inertial system 4 to the other digital input 32 of the computer 6.

The digital links 40, 42, 44 of the navigation system 1 are for example digital buses conforming to the Ethernet standard, or ARINC (used in aeronautics).

At least one of the links 42, 44 can be longer than 100 meters in some applications. The propagation time of a signal in a link of this length is around 500 microseconds.

The navigation system 1 is for example intended to be carried in a mobile carrier whose attempt is made to estimate navigation data (position, speed, acceleration, attitude, etc.). This carrier is typically an aircraft, a spacecraft, a ship or a land vehicle.

With reference to FIG. 2, the navigation system 1 implements a navigation method comprising the following steps.

The satellite positioning device 2 receives, via its antenna 8, radio navigation signals transmitted by the constellation of satellites (step 200).

From these captured signals (at least 4 signals), the processing module 10 calculates navigation data, which is conventionally called satellite navigation data. The processing module 10 also dates this satellite navigation data in a shared predetermined time scale of the GNSS system according to a method known per se (step 202), so as to produce time-stamped satellite navigation data.

By convention, it is considered in the present text that a "datestamped in a time scale" is a set of data comprising the datum itself as well as a date associated with the datum, the date being expressed in this scale of time.

The satellite positioning device 2 transmits the time-stamped satellite navigation data in the predetermined time scale via the output 16 and on the link 42 (step 204).

Furthermore, the satellite positioning device 2 generates dating signals to export a predetermined time scale.

Conventionally, these dating signals include:

• a digital dating signal carrying at least one date expressed in the predetermined time scale, • an associated analog dating signal, comprising at least one pulse synchronized in time with the date carried by the digital signal. This analog signal can conventionally be of the “TMP” type (Time Mark Puise) dating from the moment of validity of the information delivered, or of the “1PPS” type (1 pulse per second) corresponding to a signal every second “round” UTC time.

The predetermined time scale is typically coordinated universal time, commonly abbreviated as "UTC" in the literature, known from the GNSS system.

The satellite positioning device 2 transmits to the inertial system 4 the dating signals in the predetermined time scale by its output interface (step 206). More precisely, the analog dating signal is transmitted via the output 12 and the link 38, the digital dating signal is transmitted via the output 14 and the link 40.

The inertial system 4 receives on its input interface (comprising the analog 24 and digital 26 inputs) the dating signals emitted by the satellite positioning device 1 (step 400).

The inertial system 4 is synchronized in the same time scale as the satellite positioning device 2 using the received dating signals.

Furthermore, the inertial sensors 18 of the inertial system 4 acquire inertial measurement data (acceleration and rotational speed data) (step 402).

The processing module 20 of the inertial system 4 generates inertial data from the measurement data acquired by the inertial sensors 18 (step 404). The inertial data typically includes angular increments, and speed increments.

The time stamping module 28 timestamps the inertial data in the time scale on which the inertial system 4 has synchronized (step 406). In other words, during the time stamping step, a date expressed in the predetermined time scale is assigned to each inertial data item generated by the inertial system 4.

The inertial system 4 transmits the time stamped inertial data in the predetermined time scale to the computer 6, via the output 22 and the digital link 44 (step 408).

The computer 6 receives the time stamped inertial data on its input 32 (step 600).

In parallel, the additional time-stamped satellite navigation data are received by the computer 6 via the input 30, after having propagated in the link 42 (step 602).

The calculation unit 34 of the computer 6 applies a fusion or consolidation processing to the inertial data received by the input 32 and to the additional data received by the input 30 (which in this particular embodiment are navigation data by satellite), so as to generate first navigation data (step 604).

The fusion treatment is, or includes, for example, a hybridization treatment known from the state of the art. It typically includes the implementation of a Kalman filter.

It should be noted that the data transmitted respectively by the inertial system 4 and the device 2, then received by the computer 6, were previously time-stamped in the same time scale: this allows the implementation of the fusion or consolidation processing 604 implemented by calculcomputing unit 34 with slight delay, without any loss of precision. The difference in transmission time of the inertial data compared to the satellite navigation data via the digital links 42 and 44 has no effect because the instants of validity provided in the same time base make it possible to take them correctly into account. For example, the calculator 6 suffices to establish temporal correspondences between the two types of navigation data via interpolations, when their dates are different.

The computer 6 can deliver the hybridized data via the output 36 to another device, for example a carrier display device in which the navigation system 1 is on board.

Illustrated in FIG. 3 is a navigation system 1 ’according to a second embodiment, having the following differences compared to the navigation system 1 previously described.

In the navigation system Γ, no link 42 directly connects the satellite positioning device 2 to the computer 6. The satellite navigation data is in fact transmitted by the satellite positioning device 2 to the inertial system 4 which relays this data to the calculator.

For example, the time-stamped satellite navigation data are transmitted to the inertial system via the digital link 40 and then relayed to the computer 4 via the output 22 and the link 44. In this way, there is the economy of a link compared to the system according to the embodiment of Figure 1; elements 16, 42 and 30 may be absent in the navigation system 1 as illustrated in FIG. 3 by comparison with FIG. 1. The number of interface of the computer is therefore reduced.

The processor 34 of the computer 6 implements the hybridization processing already described in the context of the first embodiment on the basis of this data received via the input 32.

Furthermore, in the navigation system Γ, the dating signals used by the time stamping module 28 of the inertial system 4 to time stamp the inertial navigation data generated by the processing module 20 are not generated by the positioning device by satellite 2, but are generated by equipment 7.

The equipment 7 is for example a carrier equipment in which the navigation system 1 is embedded: the timescale can then be a local timescale for the carrier.

The equipment 7 includes a dating output interface comprising an analog output 46 and a digital output 48 analogous to outputs 12 and 14.

Furthermore, the inertial system 4 comprises an input interface for receiving the dating signals in the local time scale, this input interface may or may not be the same as that used to receive the dating signals generated by the satellite positioning device 2.

The input interface of the inertial system 4 is connected to the equipment which provides the dating signals in the local timescale.

In the embodiment represented in FIG. 3, it is the equipment 7 which supplies these dating signals to the inertial system (either because it is the equipment 7 which generated these dating signals, or because it previously received them from another device). A digital link connects the digital output 48 to a digital input 52 of the inertial system, as shown in FIG. 3, or else to the digital input 26. In addition, an analog link connects the output 46 to an analog input 50 of the inertial system, as shown in FIG. 3, or else at the analog input 24.

The time stamping module 28 converts the time-stamped satellite navigation data in UTC coordinated universal time into the time-stamped satellite navigation data in the local timescale. To implement this conversion, the time stamping module uses the dating signal in the local timescale, received from the equipment 7, as well as the dating signal in the coordinated universal timescale UTC, received from the device. satellite positioning 2.

In this way, the time stamping module 28 produces two types of time-stamped data in the same local time scale: the inertial navigation data originating from the inertial sensors 18, and the satellite navigation data which have been supplied by the communication device. positioning by satellite 1 in another time scale before being redated.

This second embodiment has the advantage of being particularly modular. The designer of the system can indeed very easily modulate its architecture (interchangeability of equipment, ease of transferring “tailor-made” functionalities into computers).

As a variant, the satellite navigation data which have been supplied by the satellite positioning device 1 may have been previously dated by the device 1 in the same time base as that used to date the inertial data. In this case, the conversion step is not necessary: the inertial system only relays the satellite data which it receives via the link 40 to the computer 6. This variant has the advantage of making it possible to dispense with the transmission of a dating signal from the satellite positioning device 2 to the inertial system 4; the link 38 normally used for this transmission can therefore be advantageously eliminated, which simplifies the architecture of the system.

The navigation systems 1 and 1 'described so far only include one inertial system 4. However, provision may be made to incorporate into one or the other of the navigation systems 1,1' several inertial systems of the types different and have several corresponding mergers taken over by the computer 6 as well as an additional consolidation function between the mergers carried out.

FIG. 4 illustrates in this regard a 1 ”navigation system according to a third embodiment comprising two inertial systems 4a and 4b, each comprising the same functional characteristics as the inertial system 4. The two inertial systems 4a and 4b are however of the types respective different: the inertial system 4a comprises for example at least one AHRS (for example two) and the other inertial system 4b comprises for example at least one 1RS (for example two), the two inertial systems 4a and 4b being capable of be deported to each other within the carrier in which the 1 ”navigation system is on board.

The computer 6 of the 1 ”navigation system implements two merges, for example in parallel:

• an AHRS / GNSS fusion carried out on the basis of inertial navigation data supplied by the inertial system 4a of the AHRS type with satellite navigation data supplied by the satellite positioning device 2a, so as to produce AHRS navigation data / GNSS, and • an IRS / GNSS fusion carried out on the basis of inertial navigation data supplied by the inertial system 4b of type 1RS with satellite navigation data supplied by the satellite positioning device 2b, so as to produce IRS / GNSS navigation data.

The computer 6 can then implement a consolidation processing taking as input the AHRS / GNSS data on the one hand and the IRS / GNSS data on the other hand, so as to produce consolidated navigation data. This consolidation treatment is known from the state of the art. A person skilled in the art can for example implement the consolidation treatment described in document FR2917853A1. Consolidation typically provides data with a higher level of integrity than the reliability of individual equipment.

Of course, the links directly connecting the devices 2a and 2b are optional. At least one of the inertial systems can be used to act as a relay between the devices 2a and 2b for the transmission of satellite navigation data to the computer, if necessary by taking care of dating them in the same time scale as the inertial data. inertial systems 4a or 4b, similarly to the second or third embodiment.

FIG. 5 thus illustrates a system Γ ”according to a fourth embodiment in which a single inertial system 4 receives satellite navigation data from several satellite positioning devices 2a, 2b, before transmitting them to the computer 6.

The invention is not limited to the embodiments described above.

For example, the satellite positioning device 2 can be replaced, in any of the previously described embodiments, by any other device capable of generating navigation aid data, for example:

• by an odometer, with a view to implementing an inertial / odometry fusion by the computer 6 during step 604, or • by another inertial system, for example with a view to consolidating data by the computer 6 during step 604.

In other words, the time-stamped satellite navigation data received by the computer 6 can be generalized to any additional data 5 capable of being combined with the time-stamped inertial data provided by the inertial system 4, provided that this additional data has been time-stamped in the same time scale as the inertial data.

Claims (10)

1. Navigation system (1, Γ, 1 ”, Γ”) comprising a first inertial system (4, 4a) and a computer (6) remote from the first inertial system (4, 4a), in which: • the first inertial system (4, 4a) is configured to: o generate first inertial data, o time stamp the first inertial data in a first time scale, using at least one dating signal in the first time scale, o transmit the first inertial data time-stamped to the computer (6 ), • the computer (6) is configured to: o receive first additional data previously generated by a third party device (2), and also time-stamped in the first time scale, o merge and / or consolidate the first time-stamped inertial data with the first time-stamped additional data, so as to generate first navigation data. 2. Navigation system (1, 1 ”) according to claim 1, in which: • the first additional data has been time-stamped by the third-party device (2) in the first time scale, • the computer (6) is configured to receive directly from the third-party device (2) the first additional data time-stamped in the first time scale . 3. Navigation system (Γ) according to claim 1, in which: • the first additional data has been time-stamped by the third-party device (2) in the first time scale, • the first inertial system (4, 4a) is configured to: o receive additional time-stamped data by the third party device (2) in the first time scale, o transmit to the computer (6) the first additional time-stamped data in the first time scale. 4. Navigation system (Γ) according to claim 1, in which: • the first additional data were time-stamped by the third party device (2) in a second time scale different from the first time scale, • the dating signal in the second time scale is supplied to the inertial system (4) by the third party device (2), • the first inertial system (4, 4a) is configured to: o receive additional time-stamped data by the third party device (2) in a second time scale, o convert the additional data received into the first time-stamped additional data in the first time scale, using the date signal in the first time scale and of the dating signal in the second time scale, o transmit to the computer (6) the first additional data time-stamped in the first time scale. 5. Navigation system (1, Γ, 1 ”) according to one of the preceding claims, in which the first time scale is coordinated universal time. 6. Navigation system (1, Γ, 1 ”) according to one of the preceding claims, in which the third device (2) is a satellite positioning device or an odometer. 7. Navigation system (1, Γ, 1 ”) according to one of the preceding claims, in which the dating signal comprises: • a digital signal carrying at least one date expressed in the first time scale, • an analog signal comprising at least one pulse synchronized in time with a date transported by the digital signal. 8. Navigation system (1 ”) according to one of the preceding claims, further comprising a second inertial system (4b), in which • the second inertial system (4b) is configured for: o generate second inertial data, o time stamp the second inertial data in the first time scale, using at least one dating signal in the first time scale, o transmit the second inertial data time stamped to the computer (6 ), • the computer (6) is further configured to: o receive second additional data previously generated by a third party device (2) and also time-stamped in the first time scale, o merge and / or consolidate the second time-stamped inertial data with the second time-stamped additional data, so as to generate second data navigation, o consolidate the first navigation data with the second navigation data. 9. Navigation method comprising steps of: • generation of first inertial data by a first inertial system (4, 4a), • time stamping of the first inertial data in a first time scale, using at least one dating signal in the first time scale, • transmission of time-stamped inertial data to a computer (6) remote from the inertial system (4, 4a), • reception by the computer (6) of first additional data previously generated by a third-party device (2) and also time-stamped in the first time scale, • fusion and / or consolidation by the computer (6) of the first inertial data with the additional data, so as to generate first navigation data. 10. A navigation method according to the preceding claim, further comprising steps of: • generation of second inertial data by a second inertial system (4b), • time stamping of the second inertial data in the first time scale, using at least one dating signal in the first time scale, • transmission of second inertial data time-stamped at the computer (6), • reception by the computer (6) of second additional data previously generated by a third-party device (2) and also time-stamped in the first time scale, • fusion and / or consolidation by the computer (6) second inertial data with the second additional data, so as to generate second navigation data, • consolidation by the computer (6) of the first navigation data with the second navigation data.