Rapid Improvements in Real Time Locating Systems
2008年8月14天 Dr Peter Harrop
One reason why the market for Real Time Locating Systems (RTLS) is growing rapidly to pass the billion dollar mark well within ten years is technology. It is improving rapidly, with new variants for the many new sub sectors of the market that are emerging. Indeed, without new, affordable technologies to cover ranges from centimetres to kilometres and other parameters differing by many magnitudes, the predicted huge market for RTLS that is shown below will not be created.
Figure 1 IDTechEx forecast of global RTLS market by value 2008-2018.
Source IDTechEx"Real Time Locating Systems 2008-2018"
Sharp improvements in UWB RTLS
Ultra Wide Band (UWB) RTLS usually gives the best accuracy and best immunity to interference in and out. That has come at a cost, limiting it to the quality end of the market. However, Time Domain has just announced a low cost version of its system and Ubisense has announced a system that ombines passive UHF and active UHF on automotive production lines. Ubisense already combines two signalling techniques Time of Arrival (TOA) and Angle of Arrival (AOA), that we explain below, for superlative performance. The functionality is also rapidly improving with advances in UWB such as the DecaWave chips that use Time Difference of Arrivals (TDOA) favoured by market leader WhereNet but have much added functionality such as mesh networking and much longer range than has previously been possible with UWB.
Hand held readers
Increasingly, the more sophisticated systems have more than a fixed infrastructure. For finding goods on foot, even outside the fixed reader network, hand held readers are increasingly offered as an extra facility. Indeed, at the bottom of the market, the Loc8tor hand held reader, used without fixed infrastructure, has had huge success in the last year. Although some may refer to this as primitive, its range and functionality exceeds that of some far more expensive fixed systems. It can set ring fencing alarms to protect assets and children etc. The tag can has an alarm button and flashing light and the hand held device vibrates, shows vectors and lights up. Indeed up to 25 tags can be programmed with a large menu driven screen. It is shown below.
Figure 2 Loc8tor hand held RTLS
Both active and passive RTLS have a place
Active RFID RTLS will not necessarily be replaced by the new passive tag RTLS. For instance, where sensing inputs must be recorded in the tag, active RFID is required and it is difficult to see how it can ever perform full mesh networking where tags talk to tags in scalable, fault tolerant systems. Active tags are also needed where there is a need to initiate a signal as with a nurse's alarm pendant. Ubiquitous Sensor Networks (USN) are being researched in many places across the world. RTLS and USN are converging.
Energy harvesting is likely to be important for much RTLS and for USN. This is where photovoltaics or other methods are used to charge batteries during use. Indeed, there are now the painfully named supercabatteries in the laboratory that combine the virtues of both batteries and capacitors. In photovoltaics, there is rapid progress with various inorganic and composite formulations being printed reel to reel for low cost and easy use because they can be stuck to uneven surfaces like tags.
Choice of signal processing
There are different signal processing techniques used even at given frequencies and sometimes more than one is used in the same system. Indeed, to improve the poor performance of Cell ID (ie zonal RTLS), infrared has been used with the same tag and some systems also provide GPS or GPRS location. For active RFID RTLS, the main options are shown below. Cell ID is losing share because it is quite expensive yet has one of the poorest accuracies. It consists of having many readers with overlapping ranges. All other systems use beams of electromagnetic radiation, which is more precise.
Figure 3 The main choices of active tag RTLS frequency and signalling compared
Source IDTechEx "Real Time Locating Systems 2008-2018"
Here TOA (Travel time trilateration against reference points also known as time of flight (TOF)) using one frequency for metering, TDOA (Differential travel time triangulation against reference points using more than one frequency for metering), AOA (Travel time triangulation against reference points (AOA) using more than one receiver for metering).
Zonal or cell ID refer to having many readers with overlapping ranges so the accuracy is poor, being simply the range of the reader. This is losing market share though some are sold with the enhancement and extra cost of infra red sensing. Received Signal Strength Indication (RSSI), a low cost method (eg Loc8tor) that is even used for some mid range systems (eg Awarepoint), when its problems accuracy and of metal and water disturbing the signal are overcome by high reader density, the system still being competitive on price. Indeed, with plug and play and self calibration due to ZigBee backhaul, the Awarepoint RTLS is highly rated and over 30 such systems have been sold in a short time.
During a surgical procedure, it can be helpful to locate things to one millimeter accuracy but in a dockyard, locating huge intermodal containers to an accuracy of several meters is fine. What these situations have in common is that they increasingly employ Real Time Locating Systems RTLS which electronically give location of a remote object in 3D all the time. Although RTLS has been around for over ten years, it really only took off in the last two years with, for example, over 100 US hospitals fitting the tags to staff and assets as certain versions of RTLS became affordable for this use. This year, with the advent of yet more versions, the market has widened even further. Indeed, the new Duracell advertisement even shows a mother finding her tagged child from a long way away in a park, using just a hand held device.
Billion dollar market
Analysts IDTechEx, Frost & Sullivan and Yankee Group have all forecasted that the RTLS business will pass one billion dollars well within the next ten years, despite it being below $200 million today. Their precise figures differ, because they did not collude in this, but clearly something is in the move. Partly, the growth is due to a widening of the market as the technologies improve in leaps and bounds. For example, there will be RTLS systems with ranges varying from a few centimeters to several kilometers and no one technology will win for all that. Already, system prices vary from a few hundred dollars to several million dollars.
Firstly, there is demand pull across many industries. Tightened safety regulations and the huge cost of lawsuits is ensuring that all oil rigs and oil refineries must be able to track personnel in 3D at all times and there are similar pressures in mining and the chemical industry. Hospitals losing 15% of assets by value every year cannot afford to continue that way. A typical airport has lost 15% of its passenger baggage trolleys at any one time and RTLS with sensing is sorely needed in military and many other applications.
In the early years, there were no standards for RTLS and single sourcing by small companies was a worry for users. Now there is a standard written around the WhereNet 2.4 GHz product and the wireless communication between the reader and the computer system is increasingly to the generally useful WiFi and ZigBee standards that have appeared. Indeed, one of the most significant recent developments is the extension of ZigBee to the Physical level "Phy" as a standard ie the tag communication can form part of a generally useful standard. That standard encompasses RTLS readers that self calibrate so it does not matter if someone moves them. It enables tags that can talk to tags in mesh networks and other delights.
For example, IDTechEx estimates that a primary market for RTLS tags will be IEEE 802.15.4a compliant devices with the functionality akin to the new Decawave ScenSor product, bringing RTLS capabilities to ZigBee and WLAN APs should even increase this. The new DecaWave chip even permits greater than 11,000 tags per 20m radius and range of hundreds of meters line of sight and 100 meter obscured says the company. Originally IEEE802.15.4a devices were slated to be ZigBee Phy replacements, reducing power consumption, increasing data rates significantly whilst affording the added benefits of mobility and ranging.
For now, the IDTechEx forecast is $52 million spent on RTLS tags in 2008 rising to $1.168 billion in 2018. IDTechEx sees a larger figure for the systems that go with these tags, of course.
Traditional RTLS systems can cost millions of dollars and there is still a market for ones that are exceptionally immune from interference and unable to cause significant interference, while being very accurate, long range, very rarely out of action and so on. That provides major scope for the top of the market offerings from market leader WhereNet and for those offering the newer Ultra Wide band RTLS. The only formidable acquisition program in RTLS is that of Zebra Technologies recently bought WhereNet and Multispectral Solutions in the USA and proveo in Germany plus Navis which has a closely allied RFID operation.
Systems offering a new mix of benefits such as easy installation, low maintenance and lower cost, rather than prioritising accuracy, availability or range, are now serving an expanding market in manufacturing, healthcare and other applications. Some use existing WiFi networks once they have been enhanced- AeroScout being leader here and Ekahau an important player. Others put in their own infrastructure variously working at Low Frequency LF, 433 MHz, UHF, 2.45GHz or UWB, which is a chosen broad band of microwave frequencies, but LF and UHF do not yet attract the bulk of orders. There are standards for most of these and they have had in common the fact that the tag needs battery and a special silicon chip, the system only being saleable if the battery lasts for at least three years for the desired duty cycle. Battery life depends crucially on the type of battery and the type of chip.
Passive tag RTLS bursts upon the scene
The rule book is now being changed with dramatic breakthroughs almost every month. In 2008, Mojix, RF Controls and Wirama have announced fully functioning RTLS that uses existing standard passive UHF labels currently selling in the hundreds of millions yearly and likely to be selling in the billions before long. These RTLS systems outperform many active (with battery) systems in range, figures of up to 600 feet being claimed. Indeed, Mojix demonstrated 300 feet in an electronically noisy, crowded environment at the RFIDJournal Live event , where the delegates voted it Best in Show. Procter and Gamble and Kraft have verified that the Mojix system works in real world applications and leading RFID system integrator Xterprise has announced a partnership with Mojix after noting over a dozen trials of the system over the last year. The Mojix system is shown below.
The Mojix system
Kovio technology is capable of replacing the silicon chip in a basic UHF tag with thousands of printed nano-silicon transistors at one tenth of the cost, when the company chooses that priority. IDTechEx believes that this could lead to even lower cost RTLS based on passive tags. Either way, widespread use of passive RFID RTLS in supply chains might result in the largest potential RTLS market of all being satisfied - that for always knowing all the time where all items in supply chains are located. This is illustrated below.
Figure 1 Typical RTLS technologies matched to market
Source IDTechEx "Real Time Locating Systems 2008-2018"
We compare the three new RTLS systems based on passive Gen 2 UHF labels and two earlier ideas as follows:
Two conferences will give the latest news
Two impending conferences will give the latest news and analysis of the rapidly expanding RTLS technologies and applications. RFID Europe September 30-October 1 in Cambridge UK www.idtechex.com/RFIDEurope and Active RFID, RTLS and Sensor Networks November 5-6 in Dallas USA www.idtechex.com/active will both have many RTLS proponents and users speaking and attending. The UK event will have Ekahau, Sonitor, Coronis. Essensium, Loc8tor, CST and other RTLS suppliers, many making new announcements and users and potential users the US Navy, Container Centralen, Lang O'Rourke, Marshall Aerospace and the UK National Health Service talking. Cambridge University will describe TINA, The Intelligent Airport - A Self-Organising, Wired/Wireless Converged Machine. The US event will have RTLS suppliers Q-Track, Awarepoint, Sonitor, Loc8tor and others speaking and many end users. Indeed, it will be exclusively focussed on Active RFID, RTLS and Sensor Networks. Both events will have visits to local centers of excellence in the subject - both users and suppliers.