Pilot flight training system and method for synchronizing units of the pilot flight training system
Patent Information
- Application Number
- EP2024812927
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-10-30
- Filing Date
- 2024-10-28
- Publication Date
- 2026-09-09
AI Technical Summary
Existing pilot flight training systems face challenges in synchronizing processing devices due to the complexity of distributing physical synchronization signals, especially when devices are geographically distant, and the intrinsic drift of synchronization signals over time.
A training system that uses a reference device as a 'time server' to generate a synchronization signal, which is requested by processing devices acting as 'time clients' at a variable frequency based on the rate of change of their internal time drift relative to the reference time.
This approach allows for reliable and accurate synchronization of processing devices, adapting the synchronization speed to the rate of change of the time difference, thereby minimizing energy consumption and improving synchronization quality.
Smart Images
Figure IB2024060597_08052025_PF_FP_ABST
Abstract
Description
[0001] "PILOT FLIGHT TRAINING SYSTEM AND METHOD FOR SYNCHRONIZING
[0002] UNITS OF THE PILOT FLIGHT TRAINING SYSTEM"
[0003] Cross-Reference to Related Applications
[0004] This Patent Application claims priority from Italian Patent Application No . 102023000022782 filed on October 30 , 2023 , the entire disclosure of which is incorporated herein by reference .
[0005] Technical field
[0006] The present invention relates to a training system of flight for pilots and a method for synchroni zing units of the training system of flight for pilots . Furthermore , the invention relates to a corresponding computer program product .
[0007] Background of the invention
[0008] Training system o f flight for pilots are known comprising a plurality of processing devices interconnected with one another so as to exchange data packets in a bidirectional manner and allow, by means of known techniques , a pilot to carry out a simulated phase of a f light mission . As is known, a training system tries to simulate the experience of flying an aeroplane as closely as possible to reality .
[0009] Generally, a first group of proces sing devices is formed by devices physically made by means of hardware units installed or installable on the aircraft (for example, a radar of the aircraft, the avionics of an aircraft, etc.) while a second group of processing devices is formed by simulated devices, such as computers provided with software which simulate the operation of a respective real device by means of, for example, differential equations or neural networks. The processing devices therefore define the distributed units of a computer network.
[0010] The processing devices of the training system are often operatively coupled to one another by means of a physical network (e.g., a network of electrical connections) or by means of wireless communication technologies (e.g., by means of emitter and receiver modules, etc.) .
[0011] Given the high complexity of the training system and the need to synchronize the processing devices with one another so as to make them work simultaneously, these processing devices generally receive a synchronization signal which is generated so as to synchronize them with one another. For example, the synchronization signal can be an external hardware signal, such as a video card v-sync or a signal transmitted via serial port. The synchronization signal is therefore common to all the processing devices and allows the synchronous operation of the latter.
[0012] However, it has been verified that this known approach for synchronizing processing devices has some disadvantages. Firstly, it can be complex to distribute a physical signal, such as the synchronization signal, to all the processing devices. In some cases in which they are geographically distant, this may also be impossible.
[0013] Furthermore, it has been verified that the synchronization signal received from the processing devices tends to drift over time. This over time intrinsic drift leads to an overall drift of the processing device which cannot be determined without the aid of a further external signal. In fact, each processing device has a time t± thereof, marked at intervals 5i specific for the processing device considered, i.e., ti=k-5i, but the various 5± can vary over time depending on the rate with which the processing devices evolve. This problem is particularly critical when trying to also synchronize other devices which, for several reasons, may be unable to receive the synchronization signal.
[0014] US 2008 / 316996 Al refers to a mobile communication network and in particular to a system for maintaining frequency synchronization between the base stations of such a network. More in general, it relates to the control of the synchronization update timing between network nodes.
[0015] An object of the present invention is to provide a training system which overcomes the drawbacks of the prior art.
[0016] Summary of the invention
[0017] According to the present invention, a training system of flight for pilots, a method for synchronizing units of the training system of flight for pilots and a corresponding computer program product are made, as defined in the appended claims which form an integral part of the present description .
[0018] Brief description of the drawings
[0019] The invention will be illustrated with reference to the accompanying drawings, which represent a preferred embodiment thereof, wherein:
[0020] - Figure 1 schematically illustrates a training system of flight for pilots; and
[0021] - Figure 2 illustrates a synchronization method for the training system of Figure 1.
[0022] Preferred embodiment example
[0023] With reference to Figure 1, a training system 10 of flight for pilots is shown.
[0024] The training system 10 comprises a reference device R and a plurality of processing devices EI,...,EN operatively coupled to one another and to the reference device R.
[0025] In particular, figure 1 shows N processing devices EI, . . . ,EN. The processing devices EI,...,EN can be divided into a first group Gi of physical devices and a second group G2 of simulated devices, similarly to what was previously described. By way of non-limiting example, the first group Gi comprises the processing devices Ei,...,Enand the second group G2 comprises the processing devices ER+I,...,EN, with n<N. For example, the processing devices EI,...,EN are operatively coupled to one another by means of a physical network (e.g., a network of electrical connections, not shown) and / or by means of wireless communication technologies (e.g., by means of emitter and receiver modules, etc.) .
[0026] The processing devices EI,...,EN communicate with one another so as to exchange data packets in a bidirectional manner and allow, by means of known techniques, a pilot to carry out a simulated phase of a flight mission.
[0027] The reference device R is a synchronization device which allows the synchronization of the processing devices EI,...,EN. For example, the reference device R can be formed by a physical device (i.e., made by means of a hardware unit installed or installable on the aircraft) or by a simulated device .
[0028] The reference device R is coupled to the processing devices EI,...,EN SO as to communicate therewith, in particular in a bidirectional manner. For example, the reference device R is coupled to the processing devices EI,...,EN by means of a network of electrical connections or in wireless mode.
[0029] The reference device R is used to generate a synchronization signal which is sent to the other processing devices EI,...,EN so as to synchronize them. In detail, the synchronization signal is indicative of a reference time of the reference device R, i.e., of a time which is calculated and updated internally in the reference device R and which serves as a reference for the processing devices EI,...,EN.
[0030] In particular, each processing device (indicated below with the reference E±, with i=l,...,N) communicates with the reference device R to request the timing signal from the reference device R, at a variable frequency which depends on criteria better described below. After having received the timing signal from the reference device R, the processing device E± synchronizes based on the timing signal, i.e., updates an internal time thereof and thus the performance of its activities based on the timing signal.
[0031] In other words, the reference device R operates as a master device which implements a "time server" software, while each processing device E± operates as a slave device which implements a "time client" software.
[0032] Thereby, the internal time of the processing devices EI,...,EN is periodically and dynamically updated so that the processing devices EI,...,EN can perform their activities in a synchronized manner, i.e., according to respective timings which depend on the same timing signal of the reference device R.
[0033] In use, the training system 10 implements a synchronization method, shown in Figure 2 with reference 30.
[0034] The synchronization method 30 is executed iteratively and Figure 2 shows a single iteration thereof corresponding to a respective synchronization, in order to simplify the description thereof. Furthermore, although only one processing device E± is referred to below, it is clear that the steps described apply similarly to each of the processing devices EI,...,EN.
[0035] In the following, the reference t± indicates the internal time (or current time) of the processing device E± considered by way of example, and the reference tR indicates the reference time of the reference device R. In detail, the reference time tR of the reference device R is calculated and updated internally in the reference device R (for example based on a clock signal generated by the reference device R) , while the internal time t± of the processing device E± is calculated and updated internally in the processing device E± based on the last time reference received from the processing device E± (i.e., from the last time that the processing device E± received the synchronization signal) , i.e., as a function of a clock signal generated by the processing device E± and starting from the last time reference received from the reference device R.
[0036] At a step SOI of the synchronization method 30, the processing device E± requests the synchronization signal from the reference device R since it is necessary to perform a synchronization of the processing device E±. In detail, this occurs by the processing device E± emitting towards the reference device R a synchroni zation request signal indicative of the synchroni zation request of the processing device E± .
[0037] At a step S 03 of the synchroni zation method 30 , the processing device E± receives the synchroni zation signal generated by the reference device R following the synchroni zation request of step S O I . In particular, the bidirectional communication between the processing device E± and the reference device R (which comprises the emi ssion of the synchroni zation request signal by the processing device E±, the reception thereof by the reference device R, the sending of the synchroni zation signal by the reference device R and the reception thereof by the processing device E± ) is performed in a time interval which is substantially negligible with respect to the timing of the actions which the processing device E± must perform, and for example occurs within a few ps . For this reason, below it is considered that this communication occurs substantially instantaneously .
[0038] The synchroni zation signal received by the processing device E± is indicative of the reference time tR of the reference device R, in particular considered at the time instant ( in the time scale of the reference device R) in which the processing device E± requests synchroni zation . The reference time tR can therefore be compared with the internal time t± of the processing device E±, to verify if they coincide (in this case, no errors or drifts occurred in the updating of the internal time t± by the processing device E± since the last synchronization request made, and therefore the processing device E± is synchronized with the reference device R) or if they are different from one another (in this case, errors or drifts occurred in updating the internal time ti by the processing device E± since the last synchronization request made, and therefore the processing device E± is not synchronized with the reference device R) . At a step S05 of the synchronization method 30, the processing device E± calculates a time difference At± based on the synchronization signal received at step S03. In particular, the time difference At± is correlated to a difference between the internal time ti and the reference time tR. For example, Ati=ti-tR.
[0039] At step S05, the time difference At± can also be stored in the processing device E±, for example in a memory space thereof (e.g., volatile memory) . In particular, the time difference At± can also be stored together with the reference time tR, so as to associate the time difference At± with the time instant in which it was calculated.
[0040] At a step S07 of the synchronization method 30, the processing device E± calculates a synchronization update frequency f± indicative of the time interval (also called synchronization time interval below) which must elapse before a new synchronization request. The synchronization update frequency f± is calculated based on the time difference At± calculated at step S05, in particular based on the rate of change of the time difference At± over time. Thereby, the synchronization time interval between the current and the next synchronization iteration dynamically varies based on the rate of change of the time difference Ati over time so as to better adapt to the behaviour of the processing device E± over time.
[0041] In detail, the synchronization time interval decreases as the time variation of the time difference At± is faster, and increases as the time variation of the time difference At± is slower. In other words, and considering that the synchronization update frequency f± is equal to the inverse of the synchronization time interval (also indicated herein with the reference T± and therefore equal to l / f±) , the synchronization update frequency f± increases as the time variation of the time difference At± increases and, conversely, decreases as the time variation of the time difference At± decreases. This allows to minimize the number of synchronization iterations (and therefore the complexity of execution and the energy consumption of the training system 10) when the internal time t± and the reference time 5R vary substantially similarly and therefore the processing device E± and the reference device R are substantially synchronous, and instead allows to increase the reliability and efficiency of the synchronization otherwise.
[0042] According to an embodiment, the synchronization update frequency f± is directly proportional to the time derivative of the time difference At±, and in detail is calculated according to the mathematical expression f±=C -d ( At±) / dt , where C is a coefficient whose value is chosen in the design phase of the training system 10, for example in a heuristic manner. For example, the coefficient C can be between about 0.01 and about 0.1 and be, for example, equal to 0.05. In particular, the time derivative of the time difference At± can be calculated based on the last values of the time difference At± which have been calculated. For example, this derivative is calculated based on the data stored in a buffer of the processing device E±, which stores a predefined number L of samples (i.e., pairs of corresponding values At± and tR) and which is updated, with each new sample acquired in step S05, by storing the new sample in place of the oldest stored sample. For example, L can be between about 10 and about 50 and be, for example, equal to 15.
[0043] For example, in step S07 the synchronization time interval T± is also calculated, in particular as Ti=l / fi.
[0044] At a step S09 of the synchronization method 30, the processing device E± updates the internal time t± based on the time difference At± so that the internal time t± depends on the reference time tR. In detail, the internal time t± is recalculated based on the time difference At± and the reference time tR. In more detail, the internal time t± is equal to the sum of the time difference At± and the reference time tR, i.e., ti=Ati+tR. Consequently, the operations of the processing device E± which are performed based on the internal time t± updated at step S09 are performed with timings which are synchronized with the reference of the reference device R and therefore also with the other processing devices EI,...,EN.
[0045] At a step Sil of the synchronization method 30, the processing device E± verifies whether a new synchronization needs to be performed, i.e., verifies whether a new synchronization (or next synchronization) condition is confirmed. The new synchronization condition is confirmed when the synchronization time interval T± has elapsed (e.g., starting from the synchronization iteration currently considered and in particular from step S07) .
[0046] If the synchronization time interval T± has not yet elapsed, the synchronization method 30 proceeds to a step S13 in which the processing device E± periodically updates the internal time ti based on the internal time t± previously calculated in step S09, before returning to step Sil to re-verify if the calibration update is necessary. In other words, at step S13 the internal time t± is updated according to the mathematical expression ti, =ti+k-5i, where ti' is the new internal time calculated at step S13, ti is the internal time previously calculated at step S09, 5± is an incremental unit of time (corresponding for example to a stroke of the clock signal) and k is an index which is initialized at 1 upon the first execution of step S13 of each synchronization iteration and which increases by one unit upon each execution of step S13 in the synchronization iteration considered.
[0047] Consequently, the synchronization method 30 repeats steps Sil and S13 throughout the synchronization time interval T± . During the synchronization time interval T±, the processing device E± performs its normal activities based on the updated internal time ti .
[0048] When the synchronization time interval T± has instead elapsed, the current iteration ends and the synchronization method 30 returns to step SOI to perform a new iteration.
[0049] The synchronization method 30 is executable in the training system 10 by means of a corresponding computer program product .
[0050] Examining the characteristics of the invention provided according to the present invention, the advantages which it allows to obtain are apparent.
[0051] In particular, the training system 10 and the synchronization method 30 allow the processing devices Ei, ...,EN to be synchronized reliably and accurately.
[0052] In fact, as previously described, two software components are used, a "time server" and a "time client". The time server operates in the reference device R while the time client operates on the processing devices EI, . . . ,EN to be synchronized. In use, the time server generates the timing signal. Each processing device E± periodically contacts the reference device R, requesting the current value of this timing. Each processing device E± then calculates the drift of such timing relative to the internal timing thereof. Each processing device E± then modulates the request interval thereof based on the variance of such drift. The processing device E± then applies the drift thus calculated to each timing request made by the processing devices EI,...,EN associated therewith, thus guaranteeing a retroactively correct synchronization with respect to the reference timing .
[0053] In particular, the fact that the synchronization time interval T± is calculated at each iteration based on the time difference At± allows to adapt the synchronization speed to the rate of change of the time difference At± over time, so as to better adapt it to the behaviour of the processing device E± over time. This differentiates the synchronization method 30 from known solutions such as the "network time protocol" (NTP ) in which the synchroni zation update frequency is fixed, causing greater energy consumption and a worse synchroni zation quality with respect to the present case . Finally, it is clear that modi fications and variations can be carried out to the invention described and illustrated herein without thereby departing from the scope of protection of the present invention, as defined in the appended claims . For example , the various embodiments described can be combined with one another so as to provide further solutions .
[0054] Furthermore , the processing devices EI , ... , EN can be entirely formed by physical devices or by simulated devices .
Claims
CLAIMS1. A training system (10) of flight for a pilot, comprising a reference device (R) and a plurality of processing devices (EI,...,EN) operatively coupled to one another and to the reference device (R) and configured to communicate with one another to allow the pilot to carry out a simulated phase of a flight mission, wherein the reference device (R) is configured to generate a synchronization signal to be sent to the processing devices (EI,...,EN) to synchronize them, the synchronization signal being indicative of a reference time (tR) of the reference device (R) , and wherein each of the processing devices (EI,...,EN) is configured to:- request the synchronization signal from the reference device (R) ;- receive the synchronization signal generated by the reference device (R) upon the executed request;- - calculate, based on the received synchronization signal, a respective time difference (At±) correlated to a difference between the reference time (tR) of the reference device (R) and an internal time (t±) of the processing device (E±) ;- calculate, based on the time difference (At±) , a respective synchronization update frequency (f±)indicative of a synchronization time interval (T±) between a current synchronization and a synchronization following the current synchronization;- update the internal time (t±) based on the time difference (At±) and relative to the reference time (tid ; and- wait for the synchronization time interval (T±) to elapse before performing the next synchronization, wherein the synchronization update frequency (f±) and the synchronization time interval (T±) depend on a rate of change of the time difference (At±) over time.
2. The training system according to claim 1, wherein the synchronization update frequency (f±) is configured to increase as the time variation of the time difference (At±) increases and is configured to decrease as the time variation of the time difference (At±) decreases.
3. The training system according to claim 1 or 2, wherein the synchronization time interval (T±) depends on the inverse of the synchronization update frequency (f±) .
4. The training system according to any of the previous claims, wherein the processing devices (EI,...,EN) comprise physical devices and / or simulated devices.
5. A synchronization method (30) for a training system (10) of flight for a pilot,the training system (10) comprising a reference device (R) and a plurality of processing devices (EI,...,EN) operatively coupled to one another and to the reference device (R) and configured to communicate with one another to allow the pilot to carry out a simulated phase of a flight mission, wherein the reference device (R) is configured to generate a synchronization signal to be sent to the processing devices (EI,...,EN) to synchronize them, the synchronization signal being indicative of a reference time (tR) of the reference device (R) , the synchronization method (30) comprising the steps of, by each of the processing devices (EI,...,EN) : a. requesting (SOI) the synchronization signal from the reference device (R) ; b. receiving (S03) the synchronization signal generated by the reference device (R) upon the executed request ; c. calculating (S05) , based on the received synchronization signal, a respective time difference (Ati) correlated to a difference between the reference time (tR) of the reference device (R) and an internal time (t±) of the processing device (E±) ; d. calculating (S07) , based on the time difference (Ati) , a respective synchronization update frequency (f±) indicative of a synchronization time interval(T±) between a current synchronization and a synchronization following the current synchronization; e. updating (S09) the internal time (t±) based on the time difference (At±) and relative to the reference time (tid ; and f. waiting (Sil, S13) for the synchronization time interval (T±) to elapse before performing the next synchronization, wherein the synchronization update frequency (f±) and the synchronization time interval (T±) depend on a rate of change of the time difference (At±) over time.
6. The synchronization method according to claim 5, wherein the step of requesting (SOI) the synchronization signal from the reference device (R) comprises generating, by the processing device (E±) and towards the reference device (R) , a synchronization request signal indicative of a synchronization request of the processing device (E±) .
7. The synchronization method according to claim 5 or 6, wherein the step of calculating (S05) the respective time difference (At±) further comprises storing the time difference (At±) in the considered processing device (E±) .
8. The synchronization method according to claim 7, wherein the step of storing the time difference (At±) further comprises storing the respective reference time (tR)associated with the time difference (At±) .
9. The synchronization method according to any one of claims 5-8, wherein the step of calculating (S07) the synchronization update frequency (f±) comprises calculating a time derivative of the time difference (At±) , the synchronization update frequency (f±) being directly proportional to the time derivative of the time difference (Ati) .
10. The synchronization method according to any one of claims 5-9, wherein the step of updating (S09) the internal time (ti) based on the time difference (At±) comprises calculating a sum of the time difference (At±) and the reference time (tR) .
11. The synchronization method according to any one of claims 5-10, wherein the step of waiting (Sil, S13) for the synchronization time interval (T±) to elapse comprises:- verifying (Sil) , by the processing device (E±) , whether a subsequent synchronization condition is confirmed, depending on the elapse of the synchronization time interval (T±) ; and- if the subsequent synchronization condition is not confirmed, updating (S13) , by the processing device (E±) , the internal time (ti) based on the internal time (ti) previously calculated in step e.
12. The synchronization method according to any one of claims5-11, further comprising repeating steps a-f for a plurality of successive iterations, each iteration corresponding to a respective synchronization.
13. Computer program product storable in a training system (10) of flight for a pilot, the computer program being designed such that, when executed, the training system (10) becomes configured to perform a synchronization method according to any one of claims 5-12.