NavVis, a mobile indoor mapping, visualization and navigation company, released new mapping software that significantly improves the accuracy of simultaneous localization and mapping (SLAM) technology in indoor environments, such as long corridors, the company said.
The software update will be available for users of the NavVis M3 Trolley and will significantly improve the accuracy of the resulting maps and point clouds. NavVis’ mobile mapping system, the M3 Trolley, builds upon SLAM to increase speed and efficiency when scanning buildings.
The images below demonstrate the impact of NavVis Precision SLAM technology. The left image depicts a long corridor mapped with a conventional SLAM system where the above-mentioned drift error has occurred. The green outline shows how the map deviates from the true structure. The image on the right shows the significantly improved map accuracy obtained when mapping the same area using the M3 Trolley with the new Precision SLAM technology.
Image: NavVis
Here is a closer look:
Image: NavVis
SLAM is a technique originally developed by the robotics industry that is now increasingly being used in surveying and autonomous driving technologies. It solves a core problem that long plagued robotics engineers by enabling a device to determine its location while simultaneously mapping an unknown environment. This is done by chaining millions of measurements into a trajectory estimate.
However, even when a device captures highly accurate individual measurements, chaining them will result in an accumulation of noise and tiny measurement uncertainties. Over time, the estimated motion will start to deviate from the true motion (drift error). This can often be observed as a slight bending of long corridors that are actually straight. All available SLAM systems — regardless of whether these use LIDARs or other sensors — are inherently affected by this phenomenon.
The NavVis Precision SLAM technology significantly reduces drift error and improves the SLAM accuracy. This is particularly evident in cases where complementary techniques such as loop closures cannot be deployed, if, for example, the building’s layout does not allow for it.
Precision SLAM even improves accuracy when SLAM anchors are used to incorporate ground control points into the mapping process.
“I am very excited about our new Precision SLAM technology,” said Stefan Romberg, head of mapping and perception at NavVis. “We are always striving for the highest possible map and point-cloud accuracy and improving SLAM is a critical component to being successful. It is widely known among SLAM developers and users that complementary approaches such as loop closures or ground control points are needed to achieve a high accuracy.
“However, with the Precision SLAM technology we have developed an approach that not only nicely complements the former techniques but is especially evident when these have little effect or cannot be used.”
Polaris Wireless, a provider of high-accuracy, software-based wireless location solutions, has signed a multi-year, multi-phase contract for delivery of a wireless location solution that complies with the Federal Communications Commission’s (FCC) most recent E911 wireless location accuracy mandate with The Alaska Wireless Network, a company wholly owned by GCI Communication Corp (GCI).
The first phase of the contract extension includes the Polaris Wireless Evolved Serving Mobile Location Center (E-SMLC) with hybrid location software for LTE networks that complies with FCC-mandated indoor location requirements. Subsequent phases include delivery of additional location technologies and hybrid algorithms as cellular networks and mobile devices continue to evolve and become more capable.
Polaris Wireless describes its hybrid location solution as inherently future proof to take advantage of improvements in cellular networks and mobile devices.
“We are excited to continue working with GCI in providing our software-based location solutions,” said Amir Sattar, vice president of global operations for Polaris Wireless. “Polaris takes great pride in GCI trusting us to provide GCI E9-1-1 callers with the highest level of location accuracy when and where they need it most.”
“We have enjoyed a long-term relationship with Polaris Wireless delivering wireless E9-1-1 location solutions for many years,” said Gene Strid, chief technology officer of GCI. “As the carriers must now locate E9-1-1 callers in challenging indoor environments, we are happy to leverage Polaris Wireless’s technological innovation and commitment in delivering high-accuracy, software-based location solutions.”
“Polaris Wireless E-SMLC product leverages all available and emerging technology to deliver the best location position accuracy we can for our subscribers’ emergency calls,” said John Myhre, vice president of wireless technology at GCI.
Fathom, a Bluetooth real-time location system (RTLS) asset tracking company, has signed an agreement with Gimbal, a manufacturer for enterprise-grade mobile engagement and location intelligence.
The partnership presents customers with the combined strengths of each company: Gimbal’s reliable beacons and over-the-air security and Fathom’s high-accuracy indoor location platform, the companies said in a joint press release.
The agreement includes joint marketing and sales referrals to common prospective enterprise customers. It also enables Fathom to distribute Gimbal beacons and leverage Gimbal Secure Mode functionality.
“With Fathom to monitor and locate their beacons, both existing and new Gimbal deployments will enjoy the best each company offers,” said Fathom CEO Guylain Roy-MacHabée. “We are building a partner ecosystem with the best global beacon vendors and we are proud to work with Gimbal. Fathom’s asset tracking customers can now purchase Gimbal beacons directly from us, including the popular coin-sized Gimbal S10 — an ideal form factor that enables exciting and secure asset tracking scenarios.”
Fathom offers next-generation indoor location technology, utilizing Bluetooth to enhance asset tracking systems. Fathom complements asset tracking systems by providing greater coverage than RFID, greater accuracy than Wi-Fi and at a lower cost than other real-time location systems like ultra-wideband (UWB).
“Fathom’s location expertise and ability to accurately locate beacons indoors without the need for a mobile app is a natural fit for the asset tracking market,” said Brian Dunphy, general manager for Gimbal’s enterprise business. “We are delighted to be working with Fathom to expand the reach of each other’s products in the marketplace.”
Gimbal harnesses the power of location and proximity to drive value and create personalized experiences for customers, using location-specific events, geofences and beacons to access deep data analytics via a sophisticated location management platform.
Orolia has synchronized a Spectracom SecureSync high-precision time server with the new Iridium Satelles Satellite Time & Location (STL) time synchronization signal powered by Iridium satellites in several indoor environments in the field. Configured with an embedded STL receiver and a small patch antenna, the SecureSync synchronized with the STL signal in several challenging indoor locations. Indoor success can be attributed in part to use of a low-Earth orbit satellite-based signal 1,000 times stronger than GPS.
The first successful synchronization was in the interior of a building in one of the most challenging urban canyons on Earth: downtown Manhattan on the 7th floor of the New York Stock Exchange. The second was in the interior of a conference center with multiple sources of potential signal interference during The Institute of Navigation event in Monterey, California. Additional successful indoor timing signal synchronization locations include MiFiD2 events near the Paris Stock Exchange, a multi-story building and inside Gibson Hall in downtown London.
More GNSS challenged locations to come, the two companies promise.
Other satellite signals — notably GNSS — have limitations indoors. The Satelles STL signal uses the narrow-band paging channels of Iridium, a one-way transmission from the satellite with a very high gain system. The STL signal is completely different from the wide band, lower gain two-way channel of the Iridium phone. The STL signal is 1,000 times stronger than GPS because it originates from the Iridium constellation of 66 satellites orbiting in a low earth orbit. It is also encrypted for high security, which greatly enhances the resilient PNT capabilities of the Spectracom product lines, specificallly the SecureSync precision time and frequency reference. SecureSync with integrated STL synchronization is available to order from the Spectracom website or by contacting a representative.
“The new STL signal is the ideal solution for those needing increased security and reliability, applications such as high frequency securities trading, financial transaction time-stamping compliance and critical infrastructure timing,” said John Fischer, vice president of Orolia for advanced R&D. “It is not only an additional signal to back up traditional GNSS, it is also stronger and more secure, adding significantly to the resiliency of high performance systems and networks that must rely on precise time synchronization.”
Having proven the ability to provide a strong and reliable alternative signal in various indoor field locations, the new globally accessible STL signal adds a significant safety net to any critical GNSS application. Adding to the mix of signals of opportunity the resiliency of positioning and timing for financial, defense and critical infrastructure is greatly enhanced.
“Orolia is focused on providing Resilient PNT solutions, and by combining and layering technology in innovative ways we help our customers meet their mission goals,” said Rohit Braggs, vice president of Orolia’s PNT networks and sources. “This new satellite-based service provides a unique signal that augments Spectracom systems, enhancing our ability to effectively mitigate emerging GPS and GNSS threats.”
Orolia is the parent company of Spectracom, McMurdo, Kannad, and Sarbe brands, focused on resilient positioning, navigation and timing (RPNT) solutions that improve the reliability, performance and safety of customers’ critical, remote or high-risk operations.
Satelles has developed and deployed a real-time PNT service based on low-Earth orbit satellites, the Iridium constellation. Satellite Time and Location (STL) signals are highly secure, penetrate deep indoors, and are available anywhere on Earth. Satelles partners with other companies to deliver secure time and location capabilities to government and commercial users worldwide.
GPS World is reporting live from CTIA Super Mobility 2016, which is being held Sept. 7-9 in Las Vegas, Nevada. CTIA’s flagship event is a convergence of everything wireless for professionals who work in the mobile technology industry, including leaders in wireless, indoor location, connected car and Internet of Things (IoT), among many others.
GPS World Senior Digital Editor Joelle Harms and Wireless editor Janice Partyka will be posting news, videos and photos this week on GPSWorld.com, Facebook and Twitter @GPSWorld.
This year’s highlights include keynote addresses from senior executives at AT&T, GSMA, Nokia, Qualcomm, Verizon, The Chernin Group, TIME Inc. and FCC. Mark Cuban, billionaire investor and owner of Dallas Mavericks, and John Legend, Academy Award and Grammy-winning musician, also will share insights on everything wireless, including next-gen 5G technology, the IoT and how mobile impacts the media, music and entertainment industries.
Decawave, which specializes in precise location and connectivity applications, has reached a milestone for its micro-location, impulse radio ultra-wideband (IR-UWB) technology, surpassing one million Decawave chips shipped.
The chip’s popularity reflects the increasing demand for accurate micro-location solutions from end users and customers within Internet of Things (IoT), consumer and industrial markets. According to the company, Decawave has a target to reach five million units shipped in the course of 2017.
Decawave offers IR-UWB wireless technology for precise location and connectivity applications that can identify the specific location of any object or person within a guaranteed indoor location accuracy of 10 centimeters.
IR-UWB is becoming a key factor in the IoT market and is impacting how developers are taking devices and smart applications to the next level of context awareness, Decawave said in a press release.
The increase in demand for accurate location-based applications is evident across sectors including consumer markets such as connected homes, phone accessories, drones and sports analytics; industrial with connected buildings, factory automation and healthcare.
Decawave technology also will be embedded in cars in 2017.
The industrial market has been the first market to leverage Decawave’s technology and several Decawave customer solutions are already in the field. Decawave has 15 industrial partners that can deliver software, hardware or turn-key systems to end customers.
“The market for next-generation indoor location technologies with improved accuracy is beginning to advance with solid use cases and adoption. UWB is clearly carving out its space, with ABI Research forecasting strong growth across a range of verticals,” said Patrick Connolly, Principal analyst at ABI Research. “The market opportunity is quite large and companies like Decawave that are leading the charge in UWB are well positioned to experience continued growth.”
Consumer products. The consumer products — some of which were presented at the Consumer Electronics Show (CES) in January — are starting to ship now. For instance, Pixie tags allow customers to accurately locate, protect and organize their valuables.
Also at CES, Decawave highlighted ShotTracker, developed with sporting-goods company Spalding, for multi-player basketball tracking. The chip was also featured in Jaguar’s connected car demonstration.
ShotTracker captures every basketball player’s statistic for multiple players in real time.
In the consumer segment, there will also be opportunities in access control, remote controls, connected light, home robot and trusted-zones applications that leverage IR-UWB accuracy, reliability and immunity to relay attack schemes to grant or deny access to wireless-networks and connected devices.
“Two years after launching the technology, Decawave continues to gain traction with 1,800 customers across 68 countries using Decawave’s IR-UWB and an extra 70 to 80 new customers each month,” said Ciaran Connell, CEO of Decawave. “This is phenomenal and shows our commitment as well as market interest and future demand. We’re thrilled that UWB is finally seeing market momentum. We know its potential and now our customers are experiencing it as well.”
Decawave’s partner Quantitec showed its RTLS indoor positioning at Nokia’s booth at Mobile World Congress and at the Bosch Connected World where it was featured in the company’s advanced localization technology, as a key element of a Track and Trace solution.
I didn’t get to this year’s IEEE/ION PLANS meeting in Savannah, Georgia, in April, but I did find a few papers that interested me. You might have read past articles of mine that looked at the challenges of indoor navigation. And, of course, unmanned vehicles technology also is one of my favorites.
So, I was pleased to find papers that addressed a few key issues for me:
An approach that employs cooperative smartphones to achieve about 3 meters indoor location.
Another look at the problems in using smartphone embedded GNSS for RTK positioning.
Relative positioning between UAVs using GNSS, radio and inertial, and also adding image processing in a GNSS denied environment.
Analysis of encounter-alerting issues for UAV detect and avoid systems.
Indoor navigation
Indoor navigation is an area which is seeing quite intense research, and several companies have now put initial products on the market. The general approach has been to use sensors within smartphones combined with radio-frequency (RF) signals which seem to be readily available in stores and malls which indoor location is finding commercial applications.
If a position can be generated by an internal GNSS receiver within the phone in an outdoor setting prior to entering a building, the trick is to carry that position forward as GNSS signals disappear when the user moves away from the entry area. Inertial sensors in the phone are usually not accurate enough to do this job on their own, so ranging using RF from Bluetooth and Wi-Fi transmitters/beacons may be integrated to provide a position solution. Magnetic sensors in the phone have also been used to detect fixed metal structures within a building and use this data to aid location determination.
The problem is that you need an up-to-date database of where the Wi-Fi and Bluetooth are located, and it has been taking a lot of work to map or “fingerprint” the interiors of buildings — and guess what, these “beacons” often are moved after a mall or store is mapped, so RF ranging can become quite inaccurate.
So, fearless investigators from the University of Buckingham and University of Northampton in the U.K. have come up with the concept of using ranging between cooperative smartphones to aid each other and achieve location accuracies of 5-10 meters.
While outdoors with good GNSS position, the inertial sensors in each phone are calibrated, each phone gets position using its internal GPS and a network is formed between the phones using their relative positions. Then when a phone goes inside the building, step counting is used to maintain relative positioning in the network. This can result in around 3 meters positioning for the interior phone.
Well, yes, not everyone has two other buddies waiting around so one guy can go in and find the classic comic store, but for applications such as firefighters, urgent/health care, and security/police, this approach might work well.
Cooperative smartphone location overview. (From “UNILS: Unconstrained Indoors Localization Scheme based on cooperative smartphones networking with onboard inertial, Bluetooth and GNSS devices,” H.S. Maghdid, A. Al-Sherbaz, N. Aljawad and I.A. Lami.)
Another paper looked hard at the options there might be to resolve problems with GPS performance which has previously precluded running RTK on smartphones. If we could achieve centimeter positioning on a mass-market basis, many current applications which are inhibited by cost, could become possible and revolutionize even the way we live. People have already used external solutions to solve some of the problems, but leading researchers at Texas U, with Broadcom and Radiosense support, may have come up with a self-contained solution.
It is known that there are issues with the capability of the GNSS chip and oscillator components in smartphones — the observables they produce are not currently of sufficient quality to sustain RTK performance. So these researchers worked with Broadcom, who supplied them with an Android smartphone, which provided access to raw code and carrier-phase outputs and was also able to process these measurements internally.
A smartphone’s Android software stack with the GNSS components and data flow highlighted. (From “On the Feasibility of cm-Accurate Positioning via a Smartphone’s Antenna and GNSS Chip,” T.E. Humphreys, M. Murrian, F. van Diggelen, S. Podshivalov, K.M. Pesyna, Jr.)
Carrier phase measurements in smartphones suffer from five anomalies not found in survey-grade GNSS receivers — but four of these can be fixed in post-processing. The remaining phase measurement error increases with time and precludes RTK centimeter-level positioning — it could be the result of round-off error due to processing limitations. Otherwise it seems possible that carrier-phase differential GNSS positioning might be achievable.
However, the researchers also studied antenna performance and found that its gain pattern was significantly affected by strong local multipath. The impact is that deep, unpredictable fading and large phase error will compromise centimeter-accurate positioning.
So we’re not quite there yet, but with a new smartphone version showing up almost every other year, it is always possible that researchers and manufacturers will eventually evolve designs in the right direction, and ultimately solve the problem.
Unmanned aerial vehicles
Meanwhile, researchers at West Virginia University have been investigating methods to maintain relative positioning between UAVs in flight. With drone “swarms” and cooperative drone missions becoming more common, if a simple method could be derived to maintain relative separation, these applications could become more prevalent, especially in a GPS denied environment.
So, with only noisy ranging radios between UAVs, and an onboard navigation system solution on each vehicle, the researchers set about developing an algorithm which can maintain relative position. The solution is complicated by the geometry between the UAVs, how often range measurements are made, and the noise in those measurements. To constrain these variables, the study was run assuming the UAVs travel at the same altitude.
The study concluded that— provided the UAVs travel in the same direction, parallel to each other — that their algorithm could find a solution all the time. The focus of the study appears to be on determining hearing and relative bearing between the vehicles and results were varied depending on the frequency of range measurements, the amount of noise and the geometry. So a few steps forward along the path towards making drones work together in a hostile environment where GPS is jammed. (See “Cooperative Relative Localization for Moving UAVs with Single Link Range Measurements,” J. Strader, Y.Gu, J.N. Gross, M. De Petrillo, J. Hardy.)
Another study on the same problem of maintaining relative position between drones was also undertaken by West Virginia University, Systems & Technology Research and the Air Force Research Laboratory. However, their solution didn’t only use ranging between vehicles. It took advantage of inertial measurements on each drone, computer vision calculations derived from downwards looking cameras on both UAVs, and finally magnetometer measurements were also added into a Kalman filter solution.
UAV platform payload diagram and assumptions. (From “Unmanned Aerial Vehicle Relative Navigation in GPS Denied Environments,” J. Hardy, J. Strader, J.N. Gross, Y. Gu, M. Keck, J. Douglas, C.N.Taylor.)
With several additional sensor measurements, the researchers were able to predict that relative positioning could be maintained in a GPS denied environment. They also considered ranging radio, magnetometer and vision update rates, and the performance/update rate of various quality inertial sensors. The principle objective is to enable accurate target hand-off between drones as one approaches the other. Overall, they found their model could support 10-meter-level position and 0.5 degree accuracy.
Finally, for safe operation of UAVs in the U.S. National Airspace System (NAS), minimum Detect and Avoid (DAA) standards for small to medium size UAVs are being developed for operations within drone-accessible airspace. DAA has to provide the “see and avoid” for unmanned aircraft systems (UAS) that pilots of manned aircraft use to avoid other aircraft. So surveillance sensor information needs to supply the UAV and the remote Pilot in Command (PIC) operator with the situational awareness needed to remain well clear of other aircraft.
Part of what DAA should provide are alerts working to universal standards for all UAS.
Zones used in alert evaluation. (From “Analysis of Alerting Performance for Detect and Avoid of Unmanned Aircraft Systems,” S. Smearcheck, S. Calhoun, W. Adams, J. Kresge, F. Kunzi.)
The research presented by CAL Analytics and General Atomics (with technical support and guidance by RTCA committee SC-228 and NASA) outlined the evaluation alerts generated when other aircraft are anticipated to penetrate into a well-clear volume around a UAV.
Alerts can be “missed,” “late” and “early” — all of which can impair DAA performance and safety and which need to characterized and mitigated. Sensors currently under consideration for use in DAA include Automatic Dependent Surveillance Broadcast (ADS-B), active surveillance transponder and airborne radar — this study looked at ADS-B and radar and the trade-off that they provide related to desirable and undesirable alerts.This analysis will likely feed into the development of UAS DAA alerting standards and requirements.
Typical DAA tracker approach. (From “Analysis of Alerting Performance for Detect and Avoid of Unmanned Aircraft Systems,” S. Smearcheck, S. Calhoun, W. Adams, J. Kresge, F. Kunzi.)
Radar surveillance errors were found to increase the probability of Missed, Late, Short, Early and Incorrect Alerts, all of which is bad news for radar. ADS-B surveillance errors increased the probability of Short, Early, and Incorrect Alerts. However, ADS-B did not lower performance as much as radar — better news for ADS-B. All levels of surveillance errors were seen to increase the amount of alerting jitter, with radar seeing the most significant undesirable effects.
Guardian UAS used in DAA tests.
Highly reliable, proven DAA systems are likely an essential part of the safety system for UAS if they are to become a regular part of operations in the NAS. General Atomics has tested a DAA system including GA’s Due Regard Radar (DRR) aboard a U.S. Customs and Border Protection (CBP) Guardian Unmanned Aircraft System (UAS), a maritime variant of the Predator B UAV. The DAA system also includes Honeywell’s Traffic Alert and Collision Avoidance System (TCAS) and Sensor Tracker, specifically designed for DAA.
Schiebel Camcopter S-100 demonstrating detect and avoid system.
And, also in December of last year, a Schiebel Camcopter S-100 flew demonstration flights with an NLR-developed AirScout Detect and Avoid System. Two helicopters flew “intruder” profiles against the UAV during the demonstration. The Camcopter S-100 flew several scenarios and “unexpectedly” encountered an intruder aircraft. The system determined in real time the corrective action to maintain separation from the intruder aircraft.
So, progress on indoor navigation, research towards running RTK on smartphones, relative positioning between UAVs, and advances in Detect and Avoid solutions for UAVs. Something of a mixed bag, but all promise further progress around different solutions for a number of market navigation segments.
Sponsored by: CSR Broadcast date: Thursday, December 4, 2014 On-Demand Available Until: Friday, December 4, 2015 Speakers: Dave Huntingford, Director of Product Management for Location, CSR; Dimitri Rubin, Senior Director of Emerging Technologies, CSR; Murray Jarvis, Consultant, CSR Summary: Indoor location has become a hot topic, carrying the promise of ubiquitous location and user context. Set to take social networking, analytics, content targeting and enterprise efficiency applications to a new level, the technology hails from a high pedestal. SiRFusion TM from CSR is a new, innovative and technically disruptive solution, combining multiple sources of information to create high quality and accurate indoor positioning, without the need for new infrastructure or site surveys. Join CSR’s experts in Indoor Location, Dave Huntingford and the CSR SiRFusion team, to learn how this innovative indoor location technology can create new revenue streams for you through accurate understanding of your customers’ location indoors. Webinar topics:
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Extraordinary though satellite navigation may be, GPS and other satellite-based constellations are limited when there is not a line-of-sight or near-line-of-sight path to at least three (and preferably more) satellites. These systems also do not provide sufficiently accurate and reliable altitude information for most applications, especially indoors. Finally, power consumption is an issue for user equipment.
It has been easy to overlook these limitations as the enormous benefits of GNSS have become pervasive, but the increasing demand especially for indoor geolocation now requires a robust solution designed for the indoors and urban canyons. Support for Terrestrial Beacon System (TBS) location technologies was incorporated in Release 13 of the Third Generation Partnership Project (3GPP). These technologies are complementary to GNSS, and provide a comprehensive solution to these limitations.
One of the TBS in development is the Metropolitan Beacon System (MBS) implementation by NextNav, which is the subject of this article. NextNav is deploying the first MBS network in the United States, using spectrum in the 920–928 MHz band, on licenses that cover about 98 percent of the U.S. urban population.
3GPP is the standards development organization for cellular wireless specifications, and is in part responsible for the popularization of GPS through its standardization in the 3GPP Release ’98 specifications. Release ’98 enabled wireless operators to adopt GPS and bring their economies of scale to GPS positioning.
Release 13 support has similar potential for MBS, enabling support for MBS in any Release 13-compliant LTE network throughout the world. As with the original standardization of GPS in 1999, incorporation of MBS in this release was driven primarily by the need for wireless carriers to provide accurate indoor geolocation for E911 calls.
MBS complements GPS by providing precise geolocation and timing indoors, in urban canyons, and other locations where GPS signals are either unreliable or unavailable. MBS receivers work seamlessly with GPS so they are as transparent to the user as satellite-based systems. MBS can provide floor-level altitude and navigation in indoor environments.
Typical mall experience: green dots show NextNav computed positions relative to ground truth (red line).
How it works
MBS transmitters are similar in many respects to GPS satellites that are deployed terrestrially. Unlike communications systems, MBS is deployed with a view toward minimizing dilution of precision (DOP) so that the signals available at any indoor or outdoor location will meet the unique requirements for accurate geolocation. DOP is an indicator of the three-dimensional positioning accuracy of a radio positioning system’s signals as they are “viewed” by a receiver.
GPS signals are typically 30 dB below the thermal noise floor at the Earth’s surface, and thus GPS receivers require a significant amount of processing resources for acquisition and tracking. Acquisition time can be quite long, up to 12 minutes in the absence of almanac and ephemeris information. Modern commercial implementations with some assistance information is typically closer to 30 seconds.
Mall store accuracy tests depicting indoor tracking performance in suburban mall environment. Dots show MBS-drive information, with no additional data from inertial or other sensors.
Throughout this time the receiver is running at full bore, drawing a considerable amount of current, the bane of any battery-operated device. MBS mitigates these problems because the 30-Watt radiated power of each terrestrially located transmitter combined with a satellite-like link budget provides greater received signal-to-noise ratio.
The result is an acquisition time without assistance information of 6 seconds or less, and 1 second if assistance information is available. The ease of acquiring and tracking MBS signals has significant implications for power draw and power management strategies.
Metropolitan beacon rooftop transmitter.
Although deploying a wireless network of any kind is a complex endeavor, MBS benefits from the ability to cover an area using fewer beacons, thanks to its relatively high RF output power (but much lower than cellular signals) and robust processing gain.
The transmitters typically share space with existing cellular systems on towers and building rooftops and are compact. The antenna is typically a 5-foot, vertically mounted, omnidirectional element.
The system provides for redundancy at both the transmitter and network levels, and the signals are encrypted for security. Like GPS, location can be calculated by the user’s device.
Baseband Change. MBS was designed to be like another constellation on a multi-constellation GNSS processor, and primarily constitutes a firmware change to modern baseband designs. The primary receiver changes are related to the analog components (accommodation for a different frequency band and higher dynamic range).
Enabling MBS in a smartphone requires a few inexpensive passive components and slight modifications to the antenna. From an RF perspective, NextNav’s MBS operating frequency is sandwiched between bands currently used by wireless carriers, so few if any changes to a standard FR lineup is required.
Tackling cellular first
Most of the billions of mobile phones shipped every year incorporate GPS receivers. Because GPS does not work reliably inside a building, however, mobile devices must fall back to ad hoc positioning methods based on communications infrastructure. This has become increasingly important because mobile wireless devices are used predominately indoors at least 70 percent of the time, according to a study by J. D. Power and Associates. This makes reliable indoor geolocation essential for consumer, commercial and public safety interests.
The MBS architecture was designed to integrate into the GPS ecosystem and integrate organically within modern mobile devices, without the need for separate chips or elaborate reengineering.
The additional benefit of determining altitude along with horizontal position is also significant. Indoors, context is determined as much by the vertical as the horizontal — for example, in a multi-level shopping mall. In emergency-response scenarios, critical seconds or minutes can be shaved off of response time if the floor in which an emergency is occurring can be reliably determined.
Control-plane architecture (LTE) for NextNav E2E.
Power and the IoT. The Internet of Things offers substantial productivity gains. Nevertheless, there have been limitations to the rapid adoption of certain IoT technologies. Among these is a fierce battle among competing low-power wireless communication standards. Lower power operations are the key for many IoT implementations, and location is one area where power savings, especially for wide-area location, are critical.
While MBS is generally designed to complement GPS, in IoT operations it has the potential to replace GPS in some cases due to power savings available from the system. Due to its terrestrial nature, the MBS signal is much stronger than GPS, enabling significant power savings. Many applications are expected to be enabled by such a system, whether for very long-life applications with intermittent position reporting to always-on location (that is, persistent tracking). Location capabilities on wearable devices are also very desirable, but because of power constraints, provision of location through GPS has been difficult to realize.
The general benefits of a terrestrial constellation also apply to non-power-limited applications, especially in urban environments and those where altitude is a critical feature. Driverless cars and unmanned aerial systems, for example, rely on GPS but also need precise 3D location accuracy.
Vertical accuracy performance of mass-market devices.Another example of vertical accuracy performance of mass-market devices.
Applications in 5G small cells
The fifth generation of carrier wireless, 5G represents another potentially significant application of MBS technology. Achieving 5G’s ambitious goals — standards are expected to be complete by 2019 — will require a massive infrastructure increase, including small base stations, or femtocells, that must be time-synchronized to avoid interfering with each other. A large percentage of these are expected to be deployed indoors.
This means wireless carriers, neutral hosts and other infrastructure operators will need to bring timing synchronization signals inside. This typically requires GPS receivers to be placed on rooftops with the received signal fed to multiple indoor locations by running cables throughout the facility.
To an operator in a metropolitan area with hundreds or even thousands of indoor small cells, this represents a large investment in capital equipment and limits customer-based installation. MBS can provide a timing signal that can be received indoors through the use of a modified multi-constellation GNSS chipset, a low-cost and convenient alternative.
Beyond cellular
The enablement of MBS in 3GPP has drawn attention from those seeking geolocation for a range of other devices. EF Johnson Technologies, a provider of radios and other equipment for public safety applications, demonstrated the integration of MBS in its Viking P25 (Project 25) radios. As P25 radios are the standard for mission-critical voice in the public safety community, the ability to carry MBS information could be a key feature for first responders.
Elder care, monitoring family members, security guards, assets, and hospitality employees: any application that experiences service limitations due to indoor lack of availability is a candidate to augment service with MBS service, or, if power is a very serious issue, simply rely on MBS alone.
Summary
MBS complements GNSS systems by providing indoor coverage, altitude positioning and lower power consumption. By leveraging the existing GNSS ecosystem, low-cost, high-volume receivers can be adopted and service become seamless among satellite and terrestrial systems.
Other indoor PNT technologies
The 2013 CSRIC Trials administered by the FCC also tested technologies from Qualcomm, Polaris Wireless and True Position.
GPS World plans to publish articles about these and other alternative technologies in upcoming issues.
Horizontal indoor accuracy now, elusive z-axis by end of year
At their advent, mobile phones were conceived to be useful for when people were, well, mobile. And in 1996 when the U.S. Federal Communications Commission (FCC) first required that a handset’s location be sent to 911 dispatchers and meet accuracy performance standards, the FCC was understandably solely interested in calls made outdoors.
Indoor FCC rules
(rmnoa357 / Shutterstock.com)
In recognizing the pervasive use of mobile phones indoors and gains in location-determining technology, last year the FCC adopted new rules that establish accuracy requirements for indoor 911 calls.
The FCC didn’t stop there and tackled vertical positioning, ordering that within six years, the elusive z-axis, or altitude, be added to requirements and meet accuracy standards in cases when there is no dispatchable location. The z-axis is critical in finding a person in a building of more than one story, whether a high-rise apartment building in Brooklyn or a three-story dormitory at a university.
This spring, a testbed for verifying location technologies began operations. The FCC required that nationwide wireless providers create an independently administered and openly transparent test bed to verify location technologies used in meeting the accuracy requirements. CTIA, the trade association for the U.S. wireless communications industry, established the 9-1-1 Location Technologies Test Bed as an independent company.
Testing is designed and administered by ATIS, an industry standards association. The testbed regions are located in metropolitan Atlanta and San Francisco and cover a wide range of building types and terrain.
Indoor testing will be performed in 20 buildings within each test region, spanning four morphology types (dense-urban, urban, suburban and rural). Test bed administrators will not divulge the technologies being tested.
No Silver Bullet. The FCC acknowledges that there won’t be one silver bullet location technology, one size fits all that will be the best location solution in all situations.
In the order released on Feb. 3, 2015, the FCC writes, “To be sure, no single technological approach will solve the challenge of indoor location, and no solution can be implemented overnight. The requirements we adopt are technically feasible and technologically neutral, so that providers can choose the most effective solutions from a range of options.
“In addition, our requirements allow sufficient time for development of applicable standards, establishment of testing mechanisms, and deployment of new location technology in both handsets and networks… Clear and measurable timelines and benchmarks for all stakeholders are essential to drive the improvements that the public reasonably expects to see in 911 location performance.”
The 9-1-1 Location Technologies Test Bed has begun indoor testing of currently deployed horizontal location technologies, and its results will be used as part of location accuracy compliance reporting to meet FCC benchmarks.
Toward the end of this year, location technology vendors will use the Test Bed to test near-term emerging horizontal and vertical location technologies, such as z-axis, that are not currently deployed by the nationwide wireless carriers.
JANICE PARTYKA is GPS World’s contributing editor for wireless. She is principal at JGP Services and provides strategy and marketing consulting to the mobile industry. She reported on a previous round of tests, the 2013 FCC-chartered Communications Security, Reliability and Interoperability Council (CSRIC) trials of NextNav, Qualcomm and Polaris technologies. See gpsworld.com/indoor-trial-results-next-fcc-chief/.
TomTom has entered a technology collaboration with sensewhere, a provider of indoor positioning technology. According to the companies, the collaboration will enable the two companies to conquer GPS black spots and bring location-based services indoors.
TomTom Indoor delivers accurate customized indoor maps of public and private venues for site operators and other partners that enable increased efficiency, cost savings and an improved customer experience.
sensewhere has developed a proprietary and patented positioning solution for mobile devices. The combination of TomTom’s maps — both indoor and traditional navigation maps — and sensewhere’s accurate indoor positioning will enable a seamless navigation experience indoors and outdoors.
sensewhere algorithms enable location for indoor locations such as shopping malls, using sensors such as Wi-Fi and Bluetooth.
“Access to indoor positioning technology, coupled with highly accurate indoor maps, means that guidance can be integrated into the day-to-day operations of a wide variety of venues, including enterprise facilities, shopping malls, airports, hospitals and more,” said Pieter Gillegot-Vergauwen, vice president, Maps Product Management, TomTom. “With the explosion of the Internet of Things, we believe that by partnering with sensewhere our customers will not only be able to gain efficiencies, but will also deliver a better experience to their own customers.”
“We are excited to help TomTom extend its navigation prowess indoors with this technology collaboration,” said Rob Palfreyman, CEO of sensewhere. “We believe this integration is a perfect fit for enterprises that need to combine location intelligence, resource planning and efficient execution.”
Where’s Waldo? sensewhere uses pinpoint people to illustrate how its system works in a home page video.
PoLTE Corporation has developed technology that harnesses the global long-term evolution (LTE) deployment to provide accurate and reliable location data.
Unlike localized solutions, such as Wi-Fi and Bluetooth, PoLTE’s technology leverages its Positioning over LTE (PoLTE) Macro software to achieve precision of 2 to 6 meters. The technology makes use of the sounding reference signals (SRS) embedded in an LTE handset user’s transmission. Using adapted radar location techniques, it converts portions of the LTE uplink signal into a probe signal.
The technology enables mobile network operators to deliver highly accurate location data to customers in indoor and outdoor environments.
Traditional macro cell location methods require at least three towers to see the user device to locate the device with precision. Historically, single tower deployments were limited in accuracy to the width of the sector created by the 120-degree antenna that was serving the user device. For example, at a distance of 1.5 kilometers from a base station, the cross range precision would be 4,000 meters. PoLTE Macro can improve the precision to less than 2 meters.
The benefits to leveraging network-based positioning include speed, flexibility, accuracy and data analytics. Customers for the technology include machine-to-machine and Internet of Things technologies, mobile advertising, crowd and customer tracking, and public safety.
