WO2000023816A1

WO2000023816A1 - On-board beacon in particular for managing vehicle fleets

Info

Publication number: WO2000023816A1
Application number: PCT/FR1999/002562
Authority: WO
Inventors: Jean-Christophe Foucault; Bernard Florenty; Gérard GOURMAND
Original assignee: Thomson Csf Detexis
Priority date: 1998-10-21
Filing date: 1999-10-21
Publication date: 2000-04-27
Also published as: AU6209499A; FR2785112B1; FR2785112A1

Abstract

The invention concerns a device, forming an on-board data transmitting beacon, comprising a radiolocation receiver (4), telecommunication means (5), a managing unit (2) interconnected with the radiolocation receiver and the telecommunication means, and controlling a standby mode and an activated mode thereof, to acquire and transmit data to a remote site at least concerning the beacon position, and autonomous means for electrically powering (30-32) the whole set. The beacon further comprises a movement detector, and its managing unit (2), provided with a permanent clock, includes at least an operational mode or scenario wherein it activates the movement detector repeatedly, while conditioning at least partially, the subsequent activation of the radiolocation receiver by the fact that the movement detector responses indicate a significant movement of the beacon.

Description

On-board beacon, in particular for the management of vehicle fleets.

The invention relates to the management of vehicle fleets, and applies in particular to the remote location of wagons.

Today we have efficient and inexpensive localization means, such as the radionavigation system called "Global Positioning System" or GPS. Likewise, mobile telephony has made great strides. Vehicle fleet managers are therefore looking for a way that enables them to know the position of their different vehicles from a distance, by transmitting information to a central site.

With today's means, it becomes possible to equip each vehicle, such as a wagon, with an on-board beacon capable of determining the position of the wagon, and of transmitting it remotely, accompanied if necessary other information .

This assumes that the beacon is first of a sufficiently low cost, then provided with a reliable autonomous electrical supply system, and finally capable of being effectively protected against damage and theft.

However, there is currently no completely satisfactory solution in this regard. The present invention therefore improves the situation.

We already know how to make an on-board data transmission beacon, comprising an autonomous electrical supply, a radiolocation receiver of the GPS type, a telecommunication means of the GSM type; it is also known to provide this beacon with a management unit, interconnected with the radiolocation receiver and with the telecommunication means, and arranged to control a standby state and an activated state thereof, for the purpose of acquiring and pass on at a remote site data relating at least to the position of the beacon.

According to a characteristic of the invention, the beacon further comprises a motion detector; and the management unit, provided with a permanent clock, is arranged with at least one working mode or scenario in which it activates the motion detector repeatedly, while at least partially conditioning the subsequent activation of the radio receiver. radiolocation by the fact that the responses of the motion detector indicate a significant movement of the wearer of the beacon.

Other characteristics and advantages of the invention will appear on examining the detailed description below, as well as the appended drawings, in which:

- Figure 1 is a block diagram of an on-board beacon;

- Figure 2 is a perspective view of the tag housing;

- Figure 3 is a block diagram of an element of Figure 1 (sequencer);

- Figure 4 is a flow diagram of the operation of the GPS radio navigation receiver of the beacon of Figure 1; - Figure 5 is a flow diagram of the operation of the GSM telecommunication device of the beacon of Figure 1; and

FIG. 6 is a flow diagram of the operation of the sequencer of the beacon of FIG. 1.

The accompanying drawings contain many elements which, for the most part, are certain. Consequently, they can not only serve to make the invention better understood, but also contribute to the definition of the latter, if necessary.

Rail freight operators must know the location of each of their cars. Although they naturally already know how to do it, it appeared interesting, in addition, to provide the wagons with a simple GPS receiver, and a mobile phone operating on a messaging system, tools that are available today at a low enough cost to be compatible with the application.

The cars are often stopped in places that are difficult to monitor closely. It is therefore necessary to provide in addition a reliable autonomous power supply system, and effective protection against damage and theft. Solar cell power supplies are well developed today. And we know how to arrange them to avoid vandalism.

The main problem is then to operate said elements together, in an on-board beacon which remains of a cost compatible with the needs of the managers of wagon fleets.

The Applicant has observed that the GPS receiver is a large consumer of energy. Indeed, each time it is "awakened", it must redo completely or almost completely the initialization operations, search for satellites "in sight", acquisition of synchronism with the pseudo-random codes of the GPS signals from these satellites, and tracking these codes and, where applicable, carriers. It should also be taken into account that GPS measurement may occasionally prove impossible in some cases.

The Applicant has also observed that the best compromise is obtained when the power supply is accompanied by a buffer battery, and sized to allow the battery to be fully charged during the seasons of good sunshine (spring and summer), while the battery ensures the passage of the seasons of low sunshine (autumn and winter) without completely discharging.

To obtain this result, without having to give prohibitive dimensions to the power supply assembly, the Applicant has paid attention to the consumption of the GPS receiver, as will be understood below. In Figure 1, the tag includes a housing 1, designed to resist attack. This box (Figure 2) is provided on its rear face with a plate 9 articulated by a hinge 90 which cannot be dismantled without special tools. It is this plate which is used for fixing to the wagon. In 91 we see ventilation openings.

The beacon includes a sequencer 2, which is here incorporated a motion detector. The power supply includes a photo-generator 30 in amorphous technology mounted apparent in the upper part of the housing 1, and connected internally to a battery, consisting of 1 or 2 blocks of 6 Volts (of 8 Ah for example), followed by a voltage converter 31, which supplies the remaining assembly, according to the lower voltages necessary for each member.

In 4 is illustrated a GPS receiver operating in C / A code, with standard precision (100 m). We use for example the TRIMBLE receiver referenced LASSEN SK8 ("extended temperature" option), or an equivalent model. This receiver uses an antenna 41. In the illustrated embodiment, there is provided a coupler 40, and another optional antenna 42, to be mounted on the other side of the wagon.

In 5 is illustrated a GSM telephone module or equivalent, with its antenna 51. It is possible to take a GSM SIEMENS module referenced "Cellular Engine Al".

In an advantageous embodiment, a mixed GPS / GSM 45 antenna, which measures approximately 3 cm, is placed in the upper part of the housing, next to the photo-generator 30. Such antennas are sold for example by the German company HIRSCHMAN.

Finally, an interface 60 is provided, with analog-digital conversion function, to a rear passage (not shown) accessible only through the plate 9 or after opening the hinge of the housing 1. This rear passage makes it possible to receive the signals wagon sensors, or connecting to a test station, like a laptop.

The sequencer (FIG. 3) includes a permanent real-time clock 20 (or RTC, for Real Time Clock), accompanied by flash memories 21 for the reconfigurable parameters, connected to the microcontroller 22 by a type I ² C bus. Through a junction OR, the clock 20 is capable of generating interruptions (or wake-up orders) applied to a microcontroller 22, provided at 24 with a circuit comprising a random access memory, a read only memory and an input / output manager (I / O). The microcontroller 22 is also connected to interfaces 25 of the sequencer card, which go on the one hand to the external interfaces 60 for the test station (PC) and / or the external sensors, on the other hand to the GPS modules and GSM, which, seen from the sequencer, are considered as sensors. The test station can also produce an interrupt, which is then applied to the microcontroller 22 by the OR junction 26.

Here, the motion sensor 23 is part of the sequencer card. Seen from the microcontroller, it is also considered as a sensor. This detector is for example the model of the MURATA company referenced PKS1-4A10.

FIG. 4 illustrates the working mode according to which the sequencer controls the GPS receiver 4.

After the initial waking up step 400, a test 402 verifies that the GPS almanacs are sufficiently recent. Otherwise, new ones are taken at 404. Next, the antenna is tested at 406 (the aforementioned TRIMBLE receiver includes such a test), with alarm 408 if the test fails. This alarm mode can be handled in various ways, including the forced sending of a special message to the central site.

Then we go to the GPS operation proper. In 410, a measurement is requested from the GPS receiver (complete, that is to say with acquisition and temporary pursuit of the C / A code). In 412, a measurement is obtained, namely the position of the beacon and the time, as well as an indication of quality. If the quality is insufficient, steps 416 and 418 cause steps 412 and 414 to be repeated N times. In the event of persistent failure, a new GPS wake-up time is set at 420 and the GPS module is put to sleep in 430. In in the normal case, step 422 stores the measured data, and the GPS module is put to sleep at 430. The sequencer 2 (or management unit) is arranged to reset its permanent clock (or RTC) 20 according to the time provided by the GPS receiver 4.

FIG. 5 illustrates the working mode according to which the sequencer controls the telephone module 5, of the GSM / SMS type, capable of working digitally with transmission of short messages (Short Message System), and, in the opposite direction, messaging service.

After the initial wake-up step 500, step 502 attempts to establish a connection to the network. If this fails, steps 504 and 506 cause the attempt to be repeated N times. In the event of persistent failure, the alarm time is reprogrammed in 508, then put to sleep in 540.

After connection, test 510 determines whether the alarm clock is for messaging call (MT) or for sending a message (MO).

In the first case, steps 512 and 514 read and store the messages, and we go to sleep 540.

In the second case, the sending of a message is carried out in 522 to the programmed telephone number of a central site. If test 524 determines that the transmission is successful, we go to sleep 540. Otherwise steps 526 and 528 authorize N attempts, after which, in the event of persistent failure, a new wake-up time is set in 530 ( GSM), and we go to sleep 540. The number of attempts N is each time selectively configurable, at the sequencer level.

FIG. 6 illustrates the basic working mode, or main program, of the microcontroller of the sequencer 2. It can result from three different events or interruptions, which wake up the sequencer.

Each beacon is provided with a working mode or scenario in memory, the basis of which is a list of sensors (sensors means all the organs to "wake up"). At a given moment, next to each sensor, the list includes the next fixed but readjustable wake-up time for the sensor concerned and a logical state quantity (or state variable, or even flag) ")) indicating whether the treatment related to the waking time has been carried out or not. The scenario also contains other rules, and in particular the periodicity (more generally the time law) fixed as the basis for the awakening of each of the sensors.

At a given moment, the clock 20 monitors the nearest wake-up time, on all of the scenario's sensors.

In 200, the alarm clock is due to the clock 20, which has just reached this "nearest alarm time". This is the current mode.

In 202, we browse the list of sensors involved in the scenario, which provides in 204 the list of sensors to activate, according to the comparison between the current time and the respective next waking hours of these sensors (waking time less than or equal to the current time, with appropriate tolerances). Two modes of operation can be envisaged.

In a first mode, the wake-up times of the various sensors are chosen sufficiently distant from each other so that the complete processing of the sensor must be the first one is finished before the second sensor wakes up.

In a second mode, the wake-up times of the various sensors can be compared. When waking up, browsing the list of sensors makes it possible to determine all those which must be woken up during the complete treatment period of the sensor to be woken up first. This allows flags (in English flag) to be placed in the scenario, corresponding to the sensors concerned, which will allow the management unit (or sequencer) to wake them up at the programmed times.

The scenario is advantageously stored in the flash memory 21.

In 206, the sensors are successively activated, for example GPS and then GSM in MT mode ("polling"). In 208, the data is stored and it is decided to send a message if it is significant, by activating the GSM in MO mode. After that, we set a new wake-up time for RTC 20 at 270, and we go to sleep 280.

In 220, the alarm clock is due to an interruption coming from the test station (maintenance). There can be, in 222, dialogue with this station, and re-configuration of all the variable quantities of the sequencer program, or of other elements; then, at 270, a new time for waking up the RTC is fixed, and we go to sleep 280. There can be in 232 a set of tests, with activation of the sensors at 234; at the end, we go to sleep 280. There can still be a simple reading of data in 242, after which we go to sleep 280.

In 260, the awakening is due to a parasite, for example a strong electromagnetic pulse. We check the time in 262, then we test if it happens before or during an activation. In the second case, a new wake-up time is fixed in 266. We finish by going to sleep 280. According to the invention, the wake-up rule of the motion detector fixes a much higher measurement rate for the latter than that of the GPS receiver. For example, the GPS receiver is designed to be woken up from 2 to 12 times a day (in spontaneous beacon mode), while the motion detector (very low energy consumption) is woken up at a rate of 5 to 30 minutes for example.

Assuming that the GPS receiver is normally woken up every 2 hours, and the motion detector every 5 minutes, there are 24 measurements of the motion detector after the GPS receiver wakes up. If these 24 measurements are negative, that is to say indicate the immobility of the wagon, we omit the alarm clock from the GPS receiver, to which we set a new alarm time. It is the same if very few measurements of the motion detector are positive, or more generally if the statistical analysis indicates that an actual movement of the beacon is unlikely, the detected movements resulting from shocks, vibrations, or other shakes - ments. The adjustment of the threshold from which it is considered that there is displacement depends on the context, and in particular on the type of motion detector used.

If the GPS alarm clock is postponed to Tgps (i + 1), its new alarm time can be set according to the basic GPS rule, in Tgps (i + 1), as if the omitted measurement had been made . We may prefer to work in another way by setting a new time closer (than Tgps (i + 1)), which is also subject to the result of motion detection. Another variant consists in shifting the GPS alarm clock gradually until the next alarm of the motion detector, while omitting this GPS alarm clock as long as the motion detection is statistically negative.

For at least some applications, it is preferable to set a limit on these omissions from the GPS alarm clock, by ensuring that the GPS is awakened at least once a day or every 2 days. The beacon described can be mounted at the end or on the side of a wagon. Of course, it can be applied to other types of vehicles or mobile objects, such as trucks, trailers and semi-trailers, river barges, or containers, for example.

On another level, a GSM type telephone system has been described. Alternatively, an equivalent system, such as satellite telephony, can be used during the implementation.

Again on another level, exchanges of messages (or data) have been described, but it is clear that these data (or messages) can be coded, the management unit then having to have an encoding / decoding module in order to be able to communicate with the central site confidentially.

Likewise, a GPS receiver has been mentioned, but other comparable radio navigation systems can be used, such as GLONASS or GNSS, for example.

Furthermore, a photo-generator of a particular type has been described, but it is clear that the invention is not limited to this type of photo-generator.

On the other hand, a motion detector of a particular type has been described, but it is clear that the invention is not limited to this type of detector.

Finally, a preferred autonomous feeding mode has been described, but it is clear that the invention is not limited to this feeding mode. It will thus be possible to use a battery power supply coupled to a battery and a converter, or else means making it possible to recover the energy of the movement.

Claims

claims

1. Device forming an on-board data transmission beacon, of the type comprising a radiolocation receiver (4), a telecommunication means (5), a management unit (2) interconnected with the radiolocation receiver and with the telecommunication means, and arranged to control a standby state and an activated state thereof, for the purpose of acquiring and transmitting to a remote site data relating at least to the position of the beacon, as well as a power supply means autonomous (30-32) of the assembly, characterized in that the beacon further comprises a motion detector (23), and in that the management unit (2), provided with a permanent clock (20) , is arranged with at least one working mode or scenario in which it activates the motion detector repeatedly, while at least partially conditioning the subsequent activation of the radiolocation receiver (4) by the fact that the responses es of the motion detector indicate a significant movement of the wearer of the beacon.

2. Device according to claim 1, characterized in that the management unit (2) is arranged to reset its permanent clock (20) according to the time provided by the radiolocation receiver (4).

3. Device according to one of claims 1 and 2, characterized in that the motion detector (23) is of the threshold accelerometer type.

4. Device according to claim 3, characterized in that the movement detector (23) is of the vibrating blade type.

5. Device according to one of the preceding claims, characterized in that the radiolocation receiver (4) comprises a receiver of the GPS type operating in C / A mode.

6. Device according to one of the preceding claims, characterized in that the management unit (2) comprises a sequencer, capable of operating according to at least one scenario, which comprises the successive activation of a plurality of functions or modules, these functions comprising the motion detector (23), the radio navigation receiver (4), a messaging call function of the telecommunication means (5), and a site call function of the telecommunication means (5), the latter conditioned by the existence of a message to transmit.

7. Device according to claim 6, characterized in that the sequencer (2) has a wake-up time memory (21), and is arranged to activate in order to implement a scenario when the wake-up time is reached.

8. Device according to claim 7, characterized in that the sequencer (2) is arranged to also activate on connection of a station, such as a microcomputer, for the purposes in particular of testing or re-setting .

9. Device according to claim 8, characterized in that the sequencer (2) is arranged to respond to a parasitic alarm clock by checking the time, conditionally followed by a re-programming of the new alarm time.

10. Device according to one of the preceding claims, characterized in that said scenario is composed of a list of sensors each accompanied by a re-adjustable alarm time and a state logic quantity indicating whether the processing related to the alarm time has been set or not.