NextNav and Broadcom Partner for Indoor Accuracy

A NextNav beacon.

On October 2, NextNav announced that Broadcom Corporation acquired a commercial license to NextNav’s Metropolitan Beacon System (MBS) technology, a so-called terrestrial constellation that brings GNSS-like performance to indoor and urban environments where satellite-based positioning is either unavailable or significantly degraded.

The agreement enables Broadcom to integrate NextNav’s location technology into its mass-market GNSS connectivity and mobility platforms, used primarily in cell phones and tablets.

NextNav President and Founder Ganesh Pattabiraman characterized the deal in a conversation with GPS World:  “This is a commercial license to a Tier 1 chipset provider, whose products are in a vast number of smart and feature phones in the country. The partnership enables our technology in a low-cost, high-volume form factor. This is important for us since we don’t make chips. We rely on partners such as Broadcom.  This is the first of many such agreements; we’ll have more through the year.”

Most wireless companies have a mobility group addressing cellular modems, the central clearinghouse for so-called connectivity: the combination of Wi-Fi, Bluetooth, GNSS, and other technologies. Standard assisted GNSS (A-GNSS) packages to date in such cases generally consist of  ephemeris from all GNSS satellite constellations supported by the wireless company’s chips, cell ID and Wi-Fi ID from base-station databases, and additional proprietary assistance mechanisms.

The NextNav MBS concept shares many operating principles with GNSS satellite constellations, but because the NextNav beacons are installed terrestrially instead of in space, they transmit sufficient signal strength for reliable reception indoors and in urban canyons where a clear view of the sky is unavailable. MBS is deployed much like a cellular network, to provide consistent indoor positioning to every building within a covered metropolitan area. MBS offers both accurate horizontal positioning and highly accurate altitude information, a particularly important capability for emergency responders in urban and indoor areas where GNSS systems tend to be most challenged.

NextNav built its MBS network across forty large U.S. markets (see list at end of story) with its own Federal Communications Commission (FCC) licensed spectrum. “We bring more a managed network providing consistency and reliability of position information,” continued Pattabiraman. “Also the vertical component that other systems do not provide.” He characterized Wi-Fi, for example, as “an unmanaged network,” subject to frequent changes without a centralized and continually updated source of certified data.

NextNav location performance was recently highlighted in side-by-side technology tests conducted by the Communications Security, Reliability, and Interoperability Council (CSRIC) of the FCC, and published in March of this year; see reportage and analysis of these tests at The Inner Edge: Who Holds the Key to Indoor Nav?

The trial compared the performance of location systems across urban, suburban, and rural areas in the San Francisco Bay Area for determining the location of callers during emergency calls (E911), a critical case for mobile-phone users. NextNav was the only technology capable of reporting a valid height or altitude estimate, enabling floor-level positioning. NextNav’s horizontal accuracy results also reduced first-responder “search rings” by 90 percent over its nearest competitor.

Don Fuchs, director of business development at Broadcom, added “Nextnav is a metropolitan area location system, which is typically a wider area than that covered by Wi-Fi. Wireless emergency assistance calling (E911) needs a wider venue covered. And across 40 metro areas. Nextnav is wide area, while Wi-Fi is essentially local area.”

Pattabiraman said that in a typical metro area, NextNav’s terrestrial constellation of beacons is deployed for maximum coverage and minimum GDOP, and is not constrained by capacity like a cellular network. He stated that the San Francisco Bay area covered by NextNav extends to 900 square miles, from South San Jose into Marin County and East Bay. “With a fraction of the beacons required for cellular coverage in the same area, which would be in the neighborhood of a few thousand antenna installations, our deploy and operating costs are much less. Less than 20 percent of that for a cellular network.”

In comparison with Locata, another recently rolled out terrestrial constellation designed to fill GNSS gaps, Pattabiraman said, “Locata and NextNav are two entirely different systems serving different needs.  We are in the mass-market commercial cell phone wide area use case, filing that gap, providing 5–10 meter accuracy, with vertical as a critical component, and full market coverage. Locata covers centimeter-level precision application in localized environments. The two companies could both eventually get to the other side [of the market-sector spectrum], but currently each of us is focused on the particular requirements of our designated market areas. Also, we operate with licensed spectrum versus the Locata operation in 2.4 GHz unlicensed.”

“At the highest level, they are both multi-lateration systems.  Time of arrival, time difference of arrival.  We arrive at our core synchronization via GPS, which has its own synchronization, but we’ve got our IP  on top of that to improve it.  Each beacon is autonomous.  You can drop it anywhere with a clear view of the sky, and it is synchronized to the rest of the network, it has its own self-synchronizing mechanisms.  Locata is a synchronized network.

“Another way of looking at it, they have a replacement for GPS. We do more complementing for GPS, we count on GPS being there.”

Broadcom’s Fuchs added, “From the perspective of a company designing GPS and GNSS client-side semiconductors, we view NextNav as a terrestrial constellation, no more difficult or challenging than adding support for any new or legacy constellation like BeiDou or GLONASS.  We see this integration as being very straightforward, we have lots of IP in the area of signal processing, these sort of signals, this sort of positioning algorithm. We add NextNav as a secondary technology for challenging urban conditions. We view this as a piece of location technology to develop and integrate as the market demands.

“In six years at Broadcom and seven before that at Global Locate (acquired by Broadcom in 2007), we have a history of turning support like this, we’ve been able to do this very quickly.  Depending on market demand, in less than a year.  I can’t lay out a roadmap at this point.  We expect to see market demand for this, certainly expect regulatory demand.  We wanted to get to the point where we can react to that in less than a year. That was the motivation to get this agreement into place, and we are now positioned.”

“We all operate under standard operating environments as specified by the FCC. We’re metro-wide just like paging towers or broadcast TV,” continued Pattabiraman. “We’re not necessarily doing anything different as regards the indoor environment.  We’re not adding anything additional to the noise spectrum or floors. Our maximum transmission is 30 watts, very small compared to cell transmission in kilowatts. It is bits per second by the time it hits the receiver.  Because it’s calibration for navigation, the network design is optimized for location. We take into account GDOP and coverage, maximizing the latter, minimize the former. There is a very low throughput. It’s a tradeoff between power and coding.  We code the heck out of this thing.  We just new a few bits to get our information through, not like cellular that needs to get megabits through.”

As to any data or issues about the human health impacts of an RF-rich indoor environment, Pattabiraman concluded, “There’s none of this concern about power into your head. We transmit only at the tower, receive only at the user. It is very, very heavily coded, like GPS, and very low-powered.  It’s not even close [to cell transmission power].  We’re a feather, they’re a hammer.”

List of NextNav Covered Metro Areas

NextNav characterizes San Francisco as built to “commercial grade” and the other markets as “Initial Builds.”

• Boston-Worcester-Lawrence, ME
• Syracuse, NY-PA
• New York-North New Jersey, NY-NJ
• Philadelphia-Wilmington-Atlantic City, PA-NJ-DE-MD
• Washington-Baltimore, DC-MD
• Greensboro-Winston-Salem-High Point, NC-VA
• Raleigh-Durham-Chapel Hill, NC
• Jacksonville, FL-GA
• Charlotte-Gastonia-Rock Hill, SC
• Orlando, FL
• Miami-Fort Lauderdale, FL
• Tampa-St. Petersburg-Clearwater, FL
• Atlanta, GA-AL-NC
• Cincinnati-Hamilton, OH-KY-IN
• Columbus, OH
• Pittsburgh, PA-WV
• Cleveland-Akron, OH-PA
• Detroit-Ann Arbor-Flint, MI
• Grand Rapids-Muskegon-Holland, MI
• Milwaukee-Racine, WI
• Chicago-Gary-Kenosha, IL-IN-WI
• Indianapolis, IN-IL
• Nashville, TN-KY
• Memphis, TN-AR-MS-KY
• New Orleans, LA-MS
• St. Louis, MO-IL
• Kansas City, MO-KS
• Oklahoma City, OK
• Dallas-Fort Worth, TX-AR-OK
• Houston-Galveston-Brazoria, TX
• San Antonio, TX
• Denver-Boulder-Greeley, CO-KS-NE
• Salt Lake City-Ogden, UT-ID
• Las Vegas, NV-AZ-UT
• Phoenix-Mesa, AZ-NM
• Los Angeles-Riverside-Orange County, CA-AZ
• San Diego, CA
• San Francisco-Oakland-San Jose, CA
• Portland-Salem, OR-WA
• Seattle-Tacoma-Bremerton, WA