GB2139047A - Data transfer systems - Google Patents

Abstract

There are many occasions when it is desirable to be able electronically to transfer data between a movable electronic data reservoir ("datavoir") and a fixed datavoir. The invention provides a system for electronically transferring data between a vehicle and a communications headquarters, in which:- a primary datavoir is located at the communications headquarters; a plurality of stationary secondary datavoirs are located at different positions within the relevant area, and are each connectable to the primary datavoir by a slow electronic data transfer link; a tertiary datavoir is carried by the vehicle; and each secondary datavoir is connectable to the tertiary datavoir by a fast electronic data transfer link; whereby data may be electronically transferred between the primary datavoir and any secondary datavoir at a slow rate while the vehicle is unconnected to the latter, and may be electronically transferred between the secondary datavoir and the vehicle-borne tertiary datavoir at a fast rate while the vehicle is connected thereto. <IMAGE>

Description

SPECIFICATION Data transfer systems This invention concerns data transfer systems, and relates in particular to the electronic transfer of data between a moveable electronic data reservoir (one mounted on a vehicle) and a fixed electronic data reservoir (one installed in, say, a building).

There are many occasions when it is desirable to be able electronically to transfer data between a moveable electronic data reservoir ("datavoir") and a fixed datavoir. A particular class of such occasions is that involving data transference between the control equipment of one or more automated fork lift trucks, moving within a warehouse, the type of data that might be transferred relating to the presence or absence of certain goods at some location. Another class of such occasions is that involving data transference between the headquarters of "emergency" organisations such as the police, the fire service and the security forces and a mobile unit of the organisation (a police car or fire engine, for example), the type of data that mightthen be transferred (from the headquarters of the mobile unit, at least) being that digital electronic data defining a map of an area or plan of a building. The matter is now described further with particular reference to the fire service and the transference of "map" data.

Ideally, every fire service vehicle en route to an incident ought to be in possession of a plan or map of all buildings within the fire ground. Such maps and plans, compiled from architect's drawings or other sources, already exist. However, because of the sheer bulk of material it is impractical for every fire service vehicle to carry a complete set of maps embracing all builidings in their area, and while, for local fires, each vehicle could acquire the relevant map from its station's stores this, too, is impractical if extended to cover areas distant from the vehicle's base.

If, however, each (or a selected number) of the fire service vehicles were fitted with a high resolution facsimile printer, preferably one based on a plain paper copier system, it would be possible to print a map en route to the incident of the data defining the map could be transferred to the vehicle. It might seem, at first sight, as though there is no problem; it is, after all, perfectly possible to transfer electronic data between a stationary and a moving installation by radio. Unfortunately, the quantity of data required to define a building plan (say) in sufficiently high resolution is far beyond the capacity of the radio channels normally available to the fire service, for the bandwidth of these channels is very limited, and practicalities dictate that no one transmission could monopolize any channel for longer than 30 seconds.

To gain some understanding of the magnitude of the problem, imagine using a map data transfer system based on conventional fascimile standards.

The most common such standard requires an A4 page to be scanned with 1728 horizontal elements and 2200 vertical elements, making a total of nearly four million elements per page. Using a conventional fire service radio channel, capable of faithfully transferring not much more than two thousand elements a second, this A4 page could not be sent in less than two thousand seconds - which is somewhat over half-an-hour! Thus, although it is indeed possible to send low resolution fascimile copies within 30 seconds of air time over an available narrowband channel, the detail held in a building map is far beyond the capabilities of any such radio-based system. It is just not practical for the firemen to wait half-an-hour for a plan of the building that is rapidly burning to the ground in front of their eyes.

The invention seeks a solution to this problem by providing each vehicle with its own datavoir, coupled to a high resolution printer, and by arranging that throughout the area in which the vehicle is operating there are located yet further datavoirs to which the vehicle's datavoir may be connected as the vehicle proceeds to the incident, which further datavoirs are connectable to a main communications headquarters datavoir by a slow data transfer link (so they can be electronically filled, or emptied, of data at leisure) but are connectable to the vehicle's datavoir by a fast, but short range, data transfer link (so that they may electronically send large quantities of data to, or receive it from, the vehicle within a few seconds), whereupon the vehicle's datavoir may, at relative leisure, output any received data to the printer so as to produce the desired map even as the vehicle continues on its way to the incident.

In one aspect, therefore, the invention provides a system for electronically transferring data between a vehicle moveable within a defined area and a communications headquarters for that area, in which a) a primary electronic data reservoir ("datavoir") is located at the communications headquarters; b) each of a plurality of stationary secondary datavoirs is located at a different position within the area, and is connectable to the primary datavoir by a slow electronic data transfer link; c) a tertiary datavoir is carried by the vehicle; and d) each secondary datavoir is connectable to the tertiary datavoir by a fast electrionic data transfer link; whereby data may be electronically transferred between the primary datavoir and any secondary datavoir at a slow rate while the vehicle is unconnected to the latter, and may be electronically transferred between the secondary datavoir and the vehicle-borne tertiary datavoir at a fast rate while the vehicle is connected thereto.

The inventive system is one for transferring data.

The data is electronic data, and is stored and transferred electronically; this is to be considered as implicit hereinafter.

The system of the invention tranfers data between a vehicle and a communications headquarters. The transference may in principle be in either direction afire service vehicle may receive data defining a map, or a police car may transmit data describing some crime - but in general it is envisaged that the transference will be primarily from the headquarters to the vehicle.

The data to be transferred is stored and transferred electronically, but beyond that it may take any form, and may relate to any subject. Presenttechnology usually requires data to be transmitted in digital form (as a series of on/off signals), rather than in analogue form, and the main use forth system, as already suggested, is to provide a fire service vehicle with a map or plan of the incident area/building.

Accordingly, the data will most likely be a serial bit stream constituting a digital representation of a map A typical plan for a large building may well require upwards of 20 megabits (20 million elements) of data.

The data is transferred between a vehicle and a communications headquarters. Clearly, the vehicle may be any sort of vehicle; police cars and fire service vehicles are two possibilities, and for the most part the latter are dealt with herein.

The vehicle is moveable within a defined area. The area may be of any shape or size, and is defined only in so far as it is the area within which are located the secondary datavoirs connectable to the communications headquarters. The 200 plus square miles of the London Fire Brigade area extends from Romford in the East to Hillingdon in the West, and from Footscray in the South to Enfieid in the North, and is controlled from a communications headquarters based at Lambeth. In the case of a large fire, requiring upwards of 20 appliances, vehicles might be called in from as far afield as Oxford (which is in an area controlled from a station at the City centre).

Located at the communications headquarters is a primary data reservoir ("datavoir") from or to which data is transferred to or from the vehicle. This datavoir is conveniently a mainframe-computercontrolled data base of many hundreds of megabits capacity in which is stored (amongst other things, no doubt) the data to be transferred. In the case of maps for fire service vehicles, for example, the datavoir includes the means for converting the original maps into digital form and storing the data, and for updating the data when the relevant sites, and thus the maps, are changed, and may incorporate means for reconverting the stored data back into its original format. This datavoir will commonly be within the defined area, though this is not necessarily the case.

Positioned at appropriate locations within the defined area are two or more secondary datavoirs.

The geographical siting of these datavoirs may be any that is convenient - for example, they may be evenly distributed throughout the area, or they may each be located at main road junctions or near, or on the route to, concentrations of buildings - depending upon the exact nature and purpose of the system, as may be the positioning of each datavoir at any particular location. So far as is concerned the latter, while the point is discussed in more detail hereinafter it may now be said that each secondary datavoir will conveniently take the form of a small box, like a biscuit tin, mounted about 1 Oft (3m) up on a building or post adjacent the roadside.

Each secondary datavoir is of course not merely a data store but includes a control unit and interface means appropriate for its links to the primary and tertiary datavoirs. The data store itself must be a fast store (a store from which the data can be read out or written in at a high rate), and in the context of this invention "fast" as applied to a data transfer rate means of the order of megabits - say, 10 - per second and upwards. The data store is desirably one that requires no or only a minimal amount of power to maintain it. Finally, the store should have a reasonably large capacity - so that it is, for example, able to hold plans of several different buildings, and thus reduce the number of secondary datavoirs within the defined area - and from 20 to 100 megabits, depending upon the locaiity, is generally acceptable. With these constraints in mind, magnetic bubble stores are preferred (individual bubble devices, such as any one of the Intel range, can presently hold up to 0.5 megabits, and can transfer this out at a rate of 0.4 megabits per second, so an array of 24 of these in parallel can transfer data at a rate of over 10 megabits per second), though semiconductor RAM chips could be employed.

The control unit may be any suitable microprocessor; an accepatable one is the Intel 8086.

Each secondary datavoir is connectable both to a slow data transfer link (to the communications headquarters) and to a fast data transfer link (to the vehicle-borne tertiary datavoir), and an appropriate interface is needed to both. As regards the slow transfer link, it is first necesssary to explain that in the context "slow" means of the order of a few - say, 10 - kilobits per second and below, and that for reasons connected with the nature of the preferred link itself (a telephone landline), the slow transfer is preferably at about 1.2 kilobits per second. Next, it must be explained that a favoured method for transferring bit-type data along a "slow" telephone line is to convert it into a series of tones of one or the other of two frequencies (so that, for example, a low tone means a "0" bit and a high tone means a "1" bit). The conversion is effected using a modulator, and the later reconversion effected using a demodulator; the converter/deconverter unit is thus known as a modem. The preferred interface means for the slow transfer link is accordingly a modem.

So far as concerns the fast transfer link (to the tertiary datavoir), "fast" means megabits per second and upwards, and this is only possible along a (serial) channel of considerable bandwidth. As explained further hereinafter, the preferred channel is an optical one (a light beam that is switched on and off at the appropriate rate and in the appropriate manner), generated by a photodiode and received by a photocell, and it is these, together with the necessary operating electronics, that constitute the preferred interface means for the fast transfer link.

Each of the secondary datavoirs is connectable to the primary datavoir by a slow data transfer link. It has already been stated that the preferred such link is a telephone landline, but other possibilities are a narrow bandwidth radio channel, a fibre optic line or even a radio data trunking system.

The purpose of the link to the primary datavoir is to enable the relevant data (for example, that defining plans of buildings within the immediate neighbourhood) to be transferred to or from the secondary datavoir, and the reason the link need only be a slow link is because the time for the transfer is in effect unlimited compared with the time needed to transfer data to or from the vehicle-borne tertiary datavoir. Thus, where map data is to be supplied to each secondary datavoir by the primary datavoir there is no disadvantage in sending it by landline over a few days if necessary (at about 1 kilobit per second a 100 megabit data store would take 100,000 seconds, or about 30 hours, to fill, and updating a 500 kilobit chunk of this store would take a mere nine minutes).

The inventive system requires a tertiary datavoir carried by a vehicle. In a fully operating system there will most preferably be a plurality of vehicles - 20 or 30 fire service or police vehicles, say - and each of them will carry a tertiary datavoir connectable with any of the secondary datavoirs.

The (or each) tertiary datavoir is, in many ways, very like the secondary datavoirs. Thus, it is not just a data store, but has in addition a control unit, interface means to the fast data transfer link, and interface means to a data transfer link to a device such as a printer - capable of providing a "hard copy" of the information (a map, for example) defined by the data being received.

The data store, like that in the secondary datavoirs, is a fast store - preferably a bubble or semiconductor memory device; in this case the latter is preferred.

The interface means to the fast data transfer link is, again like that in the secondary datavoirs, preferably an opto-electronic device (a photocell/photodiode combination together with the associated electronics).

The interface means to the other data transfer link (at the end of which is a device such as a printer) is any suitable to the device (and may be a parallel or serial interface as appropriate). In a fire service vehicle where the data is to be reconstructed as a map using a high resolution printer (such as an English Numbering Machine ESP 90), the interface is conveniently a Standard RS 232C or IEE 488 device.

The "other" data transfer link itself may be slow or fast as desired. Links to printers are typically relatively slow direct wire connections (either serial or parallel) capable of operating at from 0.6 to 9.6 kilobits per second.

Naturally, the vehicle carrying the tertiary datavoir may be any such vehicle appropriate to the organisation operating the system.

Each secondary datavoir is connectable to the vehicle-borne tertiary datavoir by a fast data transfer link. The nature of this link can in theory be of any sort - a tight beam, limited range, broadband radio channel, or even a direct wired connection - butfrom a practical point of view a light beam, especially an infra-red beam, is the simplest way to provide the desired fast transfer capability (with almost unlimited bandwidth) yet an effectively zero likelihood of interfering with any other communications system.

The light can in general be of any sort used or suggested for use as a carrier of data (and thus could be laser radiation), but it is preferably non-coherent infra-red "light" in the form of a flat, fan-shaped beam as provided by an appropriate photo-diode and lens system.

According to the system of the invention data is transferred at a slow rate between the primary datavoir and the secondary datavoirs at leisure, and as needed at a fast rate between any one secondary datavoir and the tertiary datavoir on the vehicle in the brief moment the vehicle is connected to the secondary datavoir. The "connection" between the two is naturally whatever is appropriate to the nature of the link, but where the link is not a material medium (like a wire) but is instead immaterial (iike a radiation beam) the connection is made primarily just by so physically positioning the vehicle relative to the secondary datavoir that the two interface means, one on each, are actually aligned with and transmitting to and receiving from each other. For example, an IR photodiode in the secondary datavoir interface is radiating to, and being picked up by, the IR photocell in the vehicle's datavoir interface, and similarly the secondary datavoir's interface's photocell is receiving IR radiation from the vehicle's datavoir's interface's photodiode. One simple way of assuring this - in this particular case - is to specify that each secondary datavoir's fast link interface is positioned at a standard height and at the same (left) side of the road facing outwards therefrom, and that on each vehicle the tertiary datavoir's fast link interface is positioned so as to be at the same height facing towards the (left) road side; the two datavoirs are then made connectable by appropriately positioning the vehicle relative to the road side.

When the connection between the vehicle's datavoir and the secondary datavoir has been made the transfer of data (in the relevant direction) can begin.

Where the transfer is to be to the vehicle's datavoir, however, data transfer is preferably initiated only after the vehicle's datavoir has identified itself to the secondary datavoir (thus demonstrating its "authority" to acquire data therefrom), and perhaps has also identified the particular item of data it wants transfered (though possibly all the data in the secondary datavoir could be transferred, the one item desired being sorted out by the vehicle's datavoir afterwards, it will obviously save transfer time, and datavoir memory, if only the relevant item is transfered in the first place).

Imagining the system of the invention applied to the fire service, one operational scenario might be as follows.

Dotted all over a city are areas at the kerbside where optoelectronic interface secondary datavoir boxes are fitted to buildings at the same height as corresponding optoelectronic tertiary datavoir boxes on the fire service vehicles. The kerbside areas are designated by Act of Parliament as no parking/no stopping areas, similar to existing bus lanes.

Afire service vehicle en route to a fire or other emergency, requiring data, pulls of the main carriageway into one of these areas for a few seconds.

The fire service vehicle's datavoir sends an optoelectronics signal giving its callsign and the reference number or address of the map required. The necessary data is held in store in the secondary datavoir (in a magnetic bubble device), and is transmitted at 1 OMb/sec over the optoelectronic link. The data is then collected into peripheral storage within the vehicle, and transferred more slowly to a data printer which prints the designated hard copy map.

The secondary datavoirs are updated with the fire plans via a slow speed telephone line data link via data modems. The original information is generated at a central point communications headquarters primary datavoir (in the main fire station, for example) by scanning the original map document; a rate of 1 .2Kbit'sec is envisaged. To each secondary datavoir is transferred only that data relating to buildings in its particular area.

The system of the invention might, alternatively, be applied to the control of an automated warehouse. This scenario might be as follows.

In a fully automated warehouse the fork lift trucks are driverless, and are controlled from a single control communication centre to transfer goods to orfrom bins or shelves from or to a common input or output point. Each truck is given instructions from the common output point via an optoelectronic link and secondary datavoir as previously described. It then searches the shelves by moving up to a particular point at one end of a row of shelves, where another secondary datavoir is placed containing data describing the contents of that particular block of shelves (a kind of catalogue). If the catalogue doesn't contain the required item the truck inspects the catalogues for other rows of shelves until the required item and its location on a particular shelf is found. The item is then removed from its location and taken to the output point. The datavoir at the output point is then informed of this sequence of events, and it decrements the stick list - and so on.

This system has the advantage of allowing any free space on the shelves to be used to contain any item (greater flexibility). The contents list of the whole warehouse is then completely computer controlled, and it doesn't matter where anything is since it can be found by an entirely automatic process.

An embodiment of the invention is now described, though by way of illustration only, with reference to the accompanying drawings in which: Figure l is a road map of a region within which there are two fire service areas each with its own communications headquarters and plurality of secondary datavoirs in accordance with the inventive system; and Figure 2 is a block diagram of the secondary and tertiary datavoirs useable in the inventive system.

Figure 1 is a simple road map, showing (in heavy solid line) a major road network. From the point of view of the fire services the region depicted is divided into two areas (enclosed by the light solid lines A and B) each with its own Main Fire Station and Communications Headquarters (10a and 1 0b) within which there is a primary datavoir (not shown separately). Each Communications Headquarters datavoir 10 is linked via a slow data transfer landline (the dashed lines 1 1a,b) to an area Telephone Exchange (as 12a,b), and each such Exchange 12 is linked via further slow data transfer landlines (the dashed lines, as 13a,b) to a number of secondary datavoirs (as 20a and 20b1) positioned adjacent certain road junctions. The two Exchanges are also linked (14).

In area A there is also a Supplementary Fire Station (15).

When the system is first operated, each Headquarters datavoir 10 sends (at a slow rate) to each secondary datavoir 20 the data relevant to the locality wherein that datavoir is positioned. This data is checked at regular intervals, and updated as necessary.

Imagine a situation where a large fire has broken out at position F on the map. Fire service vehicles from Station 1 OA can reach F by either of junctions Al and A2; at each of these there is a secondary datavoir 20a, and in this particular case both contain data relevant to the fire ground. Vehicles from Station 15 can most easily reach F via junctions A3 and A2; however, the datavoir A3 does not contain the relevant data (F is too far away), and the vehcile must then proceed to the datavoir at A2.

if the fire is very large, vehicles may be called in from Area B. Such a vehicle could take one of a number of routes, but all sensible routes pass junction A2, where all relevant data may be acquired.

The nature of the secondary and tertiary datavoirs is shown in more detail in Figure 2. Each secondary datavoir 20 includes a control unit (21), linked via a modem (22) to a slow data transfer line connectable to the primary datavoir 10, and linked also to a fast store (23) and an optoelectronic interface (24). Each tertiary datavoir (30) includes a control unit (31), linked to a printer (32), and linked also to a fast store (33) and an optoelectronic interface (34).

When the system is first operated, data is transferred at a slow rate from the primary datavoir 10 to the secondary datavoir 20, where first it is converted by the modem 22 from the bi-frequency tones used over the landline link into the on/off signals more suitable to the control unit 21, and then it is transferred into the fast store 23 for later recall.

In a situation where data is to be transferred to tertiary datavoir 30, the procedure - assuming the correct relative positioning of the two interfaces 24 and 34 - is as follows: 1) Via the optoelectronic fast data transfer link the tertiary datavoir signals to the secondary datavoir its identity and that of the building plan data it requires.

2) The secondary datavoir transfers the relevant data from its fast store 23 via the fast transfer link, and as it is received the tertiary datavoir stores it in its fast store 33.

3) The transfer complete (and the vehicle now proceeding to the fire!), the data is fed to the printer 32, where a hard copy of the plan is formed as required.

Claims (19)

1. A system for electronically transferring data between a vehicle moveable within a defined area and a communications headquarters for that area, in which: a) a primary electronic data reservoir ("datavoir") is located at the communications headquarters; b) each of a plurality of stationary secondary datavoirs is located at a different position within the area, and is connectable to the primary datavoir by a slow electronic data transfer link; c) a tertiary datavoir is carried by the vehicle; and d) each secondary datavoir is connectable to the tertiary datavoir by a fast electronic data transfer link; whereby data may be electronically transferred between the primary datavoir and any secondary datavoir at a slow rate while the vehicle is unconnected to the latter, and may be electronically transferred between the secondary datavoir and the vehicle-borne tertiary datavoir at a fast rate while the vehicle is connected thereto.

2. A system as claimed in claim 1, wherein the data to be transferred is a serial bit stream constituting a digital representation of a map.

3. A system as claimed in either of the preceding claims, wherein the vehicle is a fire service vehicle.

4. A system as claimed in any of the preceding claims, wherein the primary datavoir is a mainframecomputer-controlled data base.

5. A system as claimed in any of the preceding claims, wherein each secondary datavoir contains a fast data store having a data transfer rate of the order of 10 megabits per second and upwards.

6. A system as claimed in Claim 5, wherein the fast data store within each secondary datavoir is a magnetic bubble store.

7. A system as claimed in any of the preceding wherein each secondary datavoir contains, as a control unit, a suitable microprocessor.

8. A system as claimed in any of the preceding claims, wherein each secondary datavoir contains an interface to the slow data transfer link (to the communications headquarters), which interface is a modem when the link is a telephone landline.

9. A system as claimed in any of the preceding claims, wherein each secondary datavoir contains an interface to the fast data transfer link (to the vehicle-borne tertiary datavoir), which interface is an optoelectronic one when the link is an optical one.

10. A system as claimed in any of the preceding claims, wherein the slow data transfer link connecting each secondary datavoirto the primary datavoir is a telephone landline.

ii. A system as claimed in any of the preceding claims, wherein each tertiary datavoir contains, as a fast data store, a semiconductor memory device.

12. A system as claimed in any of the preceding claims, wherein each tertiary datavoir contains, as a control unit, a microprocessor.

13. A system as claimed in any ofthe preceding claims, wherein each tertiary datavoir contains, as an interface means to the fast data transfer link, an optoelectronic device when the link is an optical one.

14. A system as claimed in any of the preceding claims, wherein each tertiary datavoir contains, as an interface means to a data transfer link to a device capable of providing a "hard copy" of the information defined by the data being received, which interface means is any suitable to the device.

15. A system as claimed in any of the preceding claims, wherein the fast data transfer link by which each secondary datavoir is connectable to the vehicle-borne tertiary datavoir is a light beam.

16. A system as claimed in claim 15, wherein the light is non-coherent infra-red "light" in the form of a flat, fan-shaped beam as provided by an appropriate photo-diode and lens system.

17. A system as claimed in any of the preceding claims, wherein, when the "connection" between any one secondary datavoir and the tertiary datavoir on the vehicle is immaterial (like a radiation beam), the connection is made primarily just by so physically positioning the vehicle relative to the secondary datavoir that the two interface means, one on each, are actually aligned with and transmitting to and receiving from each other.

18. A system as claimed in any of the preceding claims, wherein, when the connection between the vehicle's datavoir and the secondary datavoir has been made, the transfer of data to the vehicle's datavoir is initiated only after the vehicle's datavoir has identified itself to the secondary datavoir, and optionally has also identified the particular item of data it wants transferred.

19. A system as claimed in any of the preceding claims and substantially as described hereinbefore.