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Wednesday, July 31, 2013

Vodafone Egypt assures security of its “tracking” technology

As reported by the Daily News Egypt: Vodafone announced it is capable of providing users Automatic Vehicle Location (AVL) tracking services with the highest available level of security to protect both their data and privacy.

A representative for the project Zakaria Nabil said Vodafone engages in “periodic searches” of its system every three months as a special security measure to protect users and their data, and users of the company’s tracking services will not have to worry about acts of piracy or hacking.

Through the service, users would be able to follow and track their vehicles, know the exact routes taken, the amount of fuel consumed, the locations in which they stop and begin moving, as well as the speed of the vehicle, Nabil said.

He said such services have long-existed in other countries, but was not made available in Egypt until recently, largely for security reasons, adding that the “service will only be permitted if it complies with specific security standards imposed by Egypt’s government.” The device itself comes with a wireless modem integrated with a GPS receiver.

He said the service can also be used to help combat acts of theft. After an act of theft has been detected, the service would work to identify and pinpoint the vehicle’s position, then inform the user via SMS of its exact location.

He added that Vodafone had first begun cooperating with the Egyptian Tracking Services for Information Technology, which is considered a partner in the project, to develop the service during Ramadan 2012.

Nabil emphasised the service’s security dimension, noting that the Egyptian Tracking Services for Information Technology Company had assisted Vodafone in tackling security for the service.

He said when users seek to log on to acquire information regarding their vehicles, they do so through a Hypertext Transfer Protocol Secure system, a security and telecommunications system which prevents users or individuals from being able to read its contents. All of the above stated security measures he said, would conform to the country’s Telecommunications Regulatory Act.

Nabil said the country’s security services stipulated that all data and special systems used must be located and operated within Egypt so as not to be monitored and reviewed by foreign elements, adding that all service data would be located in a special central database belonging to the company located in 6th of October city.

He said the service also allows drivers to determine the best possible route, in order to consume the least amount of gasoline.

Nabil said the price of the service had not yet been determined, estimating, however, that it could be between EGP 1,300 and EGP 1,500 for individuals and EGP 1,900 for companies.

Hybrid location technologies: GPS, RFID and other technologies

A typical RFID tag with an active antenna
Continued from our previous report: There are other potential technologies for finding a mobile user’s location such as Bluetooth beacons, indoor messaging systems (IMES), machine-to-machine (M2M) communications, near-field communications (NFC), radio-frequency identification (RFID), and ultrasonic beacons. Many of these techniques aren't yet widely used; except for RFID, but that may change in the near future.

RFID tags can be installed in certain pre-determined locations and then serve as reference position generators for other positioning technologies such as sensors.  More commonly, they can be used with GPS/GNSS stations to geotag the RFID tag at a particular location - something that is now fairly popular for group sports, such as triathlons, marathons, and skiing.

Many lift tickets at major ski resorts now include RFID
Not only do they indicate the status of the lift ticket,
but when combined with geotagged readers at the lift
the skiers can be provided information about lifts they
visited at the resort.
Logistics and transportation are major areas of implementation for RFID technology. Yard management, shipping and freight and distribution centers use RFID tracking technology. In the railroad industry, RFID tags mounted on locomotives and rolling stock identify the owner, identification number and type of equipment and its characteristics. This can be used with a database to identify the lading, origin, destination, etc. of the commodities being carried.

When combined with the GPS/GNSS location of the locomotive, or trucking transportation system (using vehicle tracking systems)- specific orders and equipment can be located in near-real-time (if they are in a wireless coverage area).  For instance - in produce transportation (which is usually RFID tagged), additional information from the vehicle tracking system can also indicate the temperature of the produce during the transportation process.

RFID tagged packages can be geotagged using vehicle or
fleet tracking systems that utilize GPS/GNSS for location
In commercial aviation, RFID technology is being incorporated to support maintenance on commercial aircraft. RFID tags are used to identify baggage and cargo at several airports and airlines.

Many hospitals also utilize RFID tags for patient tracking, as well as to keep track of critical and potentially dangerous drugs.

Some countries are using RFID technology for vehicle registration and enforcement. RFID can help detect and retrieve stolen cars.  RFID cards are used for access control to public transport.
In London travelers use Oyster Cards on the tube, buses and ferries. It identifies the traveler at each turnstile and so the system can calculate the fare.  It's possible in the future that vehicles may include RFID tags for licensing, and VIN identification.

A runners RFID gate.  It is geotagged
when it is setup using GPS/GNSS and
as the runners pass through the gate
or over the pad, their identifying RFID
is geotagged and time-stamped, and
Wi-Fi is used to transfer the information
to a central database - and then
forwarded for near-real-time updates on
the runners progress - or for later
analysis with additional data.
Due to some poor marketing information, there has been some confusion regarding the functionality of RFID and GPS/GNSS; some have thought that the RFID tags can be used for location tracking on their own.  That is not the case.  RFID tags must be used with an RFID 'reader' that is in the proximity of the RFID tag.  The reader itself may be geotagged, so that the general location of the RFID tag can be registered for that time and date - but without the RFID reader and an additional geotagging location system, the devices cannot provide their current position.

One of the key enablers of hybrid positioning is an entity that can intelligently determine which positioning technique to use depending on reported readings from the mobile device. This entity may reside on the mobile device, on the network, or on some combination thereof. For example, the central database server for Wi-Fi positioning may be on the network, but a client on the device could get “snippets” of the database relevant to the current location. Termed the positioning engine, it can implement a position calculation function (PCF) using Kalman filters to process input data from a variety of sources, for example.

Hybrid location technologies simultaneously carry out all of these positioning techniques. Depending on the reported readings, the positioning server prioritizes certain methods over others. In addition, methods that provide a fast, low-accuracy fix may be prioritized over those that are slow but provide high-accuracy fixes.

RFID tags for runners can be included on
the shoe, or the wrist.  The shoe is usually
preferred since it is closer to the RFID reader.
Positioning may occur in MS-assisted (mobile station) or MS-based mode. In the MS-assisted mode, the positioning server calculates the final position based on measurements provided by the mobile device. In MS-based mode, the mobile device (smartphone, vehicle tracking device, etc) calculates the position based on its own measurements and optionally reports the final position to the server - either in near-real-time, or as a passive store and forward function.

RFID tracking for marathons would be considered an MS-assisted mode, since the geotagged and time-stamped information regarding the runner is done at the RFID gate.

Smartphone tracking using GPS/GNSS would be MS-based mode.

One of several fitness bands currently
available on the market.
A combined or hybrid system could use both technologies - the RFID tracking system to provide near-real-time runner location. Using a local smartphone system, combined with a Bluetooth biometric system such as a fitnessband or activity tracker.  The fitness band sending information to the connected smartphone system which then combines location, altitude, instantaneous speed, a highly accurate time-stamp, and the biometric data collected such as heart rate, oxygenation levels, calories burned, etc.

This data can be forwarded from the smartphone (as a wireless network is available during the activity) to the central server that is also collecting RFID location data for the runner.  The server can then post-process any critical biometric data to provide additional alerts or updates (via email or SMS) to either the runner, family, or coaching staff as needed.

Hybrid tracking systems are likely to be used more in the future as technology progresses in order to provide multiple redundant methods of location tracking under changing environmental conditions, as well as to provide geotagged data for more sophisticated analysis and functionality.

Sprint lost 2M subscribers after Nextel network went dark

Sprint pulled the plug on its old Nextel iDEN
network in Q2 triggering a huge exodus of customers.
With new spectrum from Clearwire and new capital
from SoftBank, though, the rest of the year looks brighter.
As reported by Gigaom: Sprint Corporation's first earnings report as a SoftBank-owned company wasn't exactly a positive one. Sprint shed 2 million customers in the second quarter, nearly 4 percent of its subscriber base. The big reason was Nextel, which Sprint shut down completely at the end of June.

The network shutdown resulted in 1.3 million iDEN subscriber losses, but that wasn't Sprint’s only pain point. Its retail prepaid and its wholesale connection businesses also took big hits. The only area where Sprint saw growth was in postpaid contract customers, which increased by 194,000.

That customer exodus contributed to the widening of its quarterly net loss to $1.6 billion from $1.4 billion a year ago. Sprint’s revenues, however, remained steady at $8.9 billion both quarter over quarter and year over year.
Sprint CEO Dan Hesse

Sprint executives at Tuesday’s earnings call, however, said the worst was behind them. With the iDEN network fully decommissioned, the steady stream of fleeing Nextel customers will now cease. Sprint’s acquisition of Clearwire and SoftBank’s majority investment in Sprint officially closed in the third quarter, giving Sprint a huge infusion of both capital and spectrum. Sprint CEO Dan Hesse said that cash and those airwaves will allow Sprint to become a much stronger competitor and build one of the most powerful networks in the country.

Sprint’s immediate priority is its LTE rollout. Sprint is one of the few carriers still offering unlimited plans. Once those plans are combined with LTE’s superfast speeds across its footprint, Sprint will have a key way to differentiate itself from Verizon Wireless and AT&T.

To that end, Sprint announced Tuesday it has extended LTE coverage to 40 new markets, most of them small cities with Philadelphia; Portland, Ore.; Oakland, Calif.; and Jacksonville, Fla., being the exceptions. Sprint has been bringing LTE to the big cities gradually since it began its roll-out last year. Last week, it turned on its new 4G service across the Bronx and Brooklyn, but not New York’s other three boroughs. Now it’s starting its Bay Area LTE expansion in Oakland before making its way to San Francisco.

Sprint now has LTE in 151 markets, though it hasn't yet revealed how much of the population is now covered by its LTE umbrella.

Tuesday, July 30, 2013

Hybrid location technologies: GPS, cellular ID, and triangulation - trilateration

The handset and the base-stations interact to implement
observed TDOA positioning.  The RTT measurement
is used for eCID mobile location.
As continued from our previous reportCell ID referencing is a network-based positioning method where the user's equipment (UE) or mobile device position is estimated depending on the cell it is connected with. In the enhanced cell ID (eCID) method, the handset sends cell measurements to the network, which can be used to better estimate the position. Measurements can include (depending on the radio access technology or RAT) round-trip time (RTT) and timing advance. These methods can be used in any cellular network, but the specific eCID position estimation techniques may be proprietary. They are accurate from 250 to 1000 m.

Location measurements involving distances is referred to as 'trilateration' and measurements involving angles is called 'triangulation'.  A third method is called multilateration which uses difference in distances or absolute measurements of time-of-flight from three or more sites at known locations.  GPS position location uses a type of trilateration.  eCID can use one or more of these techniques as a hybrid mobile tracking solution.

For some eCID location techniques, fingerprinting methods are similar to the approach used for Wi-Fi positioning. A central database is created with geotagged cell information, such as received signal strength indication (RSSI), cell ID, real-time difference (RTD), and network measurement record (NMR) in GSM. The mobile tracking device reports currently observed network information from the serving cell and all other nearby cells. This information is used as an input to a fingerprinting algorithm that estimates the mobile device position. Accuracy is 100 to 300 meters.

In time difference of arrival (TDOA) methods (downlink only), the mobile device detects the TDOA of signals between the serving base-station and one or more neighbors. The time differences can be used to estimate the mobile tracking device position. Typically, TDOA methods are more effective in synchronized networks. Accuracy ranges from 25 to 300 m. Common applications include:
  • CDMA/advanced forward link trilateration (AFLT): Time differences in pilot signals from the serving cell and the reference cell are detected and used for positioning.
  • LTE/observed TDOA (OTDOA): Special cell-specific reference signals, called positioning reference signals (PRS), are used for the time difference measurements.
The key handset factors that enable good performance vary depending on the technology. They all require the mobile device to be able to continuously measure the signals necessary for enabling the technology, while at the same time handling all the other call and data functionality required.

Positioning must be conducted in connected mode at the same time as various network procedures such as handovers, circuit-switched fall back (CSFB), and cell reselections. Cellular positioning typically does not provide as high-grade accuracy as A-GNSS, but it can assist in deriving a quick, coarse location, as well as provide an alternative for GPS or GNSS when indoors.

Foreign Airlines to Use GPS for San Francisco Landings

Asiana Airlines Inc. flight 214 failed to reach the runway
at San Francisco International Airport before touching down
 on July 6, 2013, causing the first fatal commercial plane
accident in the U.S. in four years.
Photographer: David Paul Morris/Bloomberg
As reported by Bloomberg News: Non-U.S. carriers landing at San Francisco International Airport, where a plane flown by South Korea’s Asiana Airlines Inc. (020560), plowed into a seawall, must use global-positioning systems when landing, regulators said.

The U.S. Federal Aviation Administration issued the requirement and cited an increase in the number of aborted landing approaches since the July 6 crash of Asiana Flight 214, which killed three people. Jets executing the maneuver included one from Taiwan’s Eva Airways Corp. (2618), the FAA said yesterday.

Flight 214’s crash rekindled concern in the U.S. that foreign pilots rely too heavily on automated systems instead of flying manually. The Boeing Co. 777 neared the San Francisco airport using visual cues and its crew didn't comment on a critical loss of airspeed until it was less than 100 feet (30 meters) off ground, investigators have said.

“The FAA has done a good thing here,” said John Nance, an aviation safety consultant and a former commercial pilot. “They’ve got enough of our tower operators that can tell you when you assign a visual approach to these pilots from foreign carriers, they’re all over the sky.”

The increase in aborted landings, which are known as go-arounds, involved foreign airlines flying visual approaches, the FAA said in an e-mailed statement. Until the glide-slope indicators are available on Runways 28 Left and 28 Right in late August, the agency will assign instrument approaches to foreign carriers, according to the statement.

Eva Airways
One of the go-arounds being reviewed by the FAA involved an Eva Airways flight on July 23 in which a plane approached San Francisco at a lower altitude than is normal, according to the U.S. agency.
Airport construction closed the glide-slope indicator on the day of the Asiana crash, the first fatal airliner accident in the U.S. in four years. Instead, pilots were instructed to use visual approaches, U.S. National Transportation Safety Board Chairman Deborah Hersman said earlier this month.

Three aviators who flew for Asiana or who helped train crews in Korea said in interviews this month that pilots for the Seoul-based airline rarely flew manually, even though they were well-trained on automated systems. The glide-slope indicator helps pilots stay on the right path toward touchdown, and is vital when visibility is limited.

South Korea’s government has begun an investigation to determine whether Flight 214’s crew was appropriately trained. Two South Korean pilot unions, meanwhile, have said the NTSB’s focus on “possibility of pilot error” risks skewing the results of the U.S. inquiry into the accident.

‘Major Disconnect’
Nance, the consultant, said the Asiana case underscored the danger of overdependence on technology.

“In Asiana, you had two senior pilots up there who weren’t really pilots, they were systems operators,” said Nance, who is based in University Place, Washington. “This has nothing to do with intellect. It is a major disconnect between policies that the nations and the International Civil Aviation Organization and basically the world’s airlines have signed onto with increasing automation.”

The next step should include barring all foreign carriers from flying into the U.S. until their pilots are properly trained to fly under visual conditions, Nance said. With technology always vulnerable to failure, pilots need the skills to fly manually so they can handle emergency situations, he said.

“If we’re going to put a pilot up here, we need to have him or her knowledgeable of what it means to be a pilot,” Nance said. “That means when everything else goes to heck in a handbasket, you can fly the airplane.”

The San Francisco Chronicle reported the requirement yesterday.

Monday, July 29, 2013

NASA Van Allen radiation belt probes provide data to help predict space weather for satellites

As reported by Nanowerk News: Using data from NASA satellites, scientists have discovered a massive particle accelerator in the heart of one of the harshest regions of near-Earth space, a region of super-energetic, charged particles surrounding the globe and known as the Van Allen radiation belts.

New results from NASA's Van Allen Probes show the acceleration energy is in the belts themselves. Local bumps of energy kick particles inside the belts to ever-faster speeds, much like a well-timed push on a moving swing. Knowing the location of the acceleration within the radiation belts will help scientists improve predictions of space weather, which can be hazardous to satellites near Earth such as the GPS and GNSS satellites in Low Earth Orbit (LEO). The results were published Thursday in the journal Science.

This video illustrates changes in the shape and intensity of a cross section of the Van Allen belts.

"Until the 1990s, we thought the Van Allen belts were pretty well-behaved and changed slowly," says Geoff Reeves, lead author on the paper and a radiation belt scientist at Los Alamos National Laboratory in Los Alamos, N.M. "With more and more measurements, however, we realized how quickly and unpredictably the radiation belts change. They are basically never in equilibrium, but in a constant state of change."
In order for scientists to understand such changes better, the twin Van Allen Probes fly straight through this intense area of space. One of the top priorities for the mission, launched in August, is to understand how particles in the belts are accelerated to ultra-high energies.

By taking simultaneous measurements with advanced technology instruments, the Van Allen Probes were able to distinguish between two broad possibilities on what accelerates the particles to such amazing speeds. The possibilities are radial acceleration or local acceleration. In radial acceleration, particles are transported perpendicular to the magnetic fields that surround Earth, from areas of low magnetic strength far from Earth to areas of high magnetic strength closer to Earth. Physics dictates particle speeds in this scenario will increase as the magnetic field strength increases. The speed of the particles would increase as they move toward Earth, much the way a rock rolling down a hill gathers speed due to gravity.
Simulated Van Allen Belts generated by a plasma thruster
 in tank #5 Electric Propulsion Laboratory at the
 then-called Lewis Research Center, Cleveland, Ohio.

The local acceleration theory proposes the particles gain energy from a local energy source, similar to the way warm ocean water can fuel a hurricane above it.

Reeves and his team found they could distinguish between these two theories when they observed a rapid energy increase in the radiation belts Oct. 9. The observations did not show an intensification in particle energy starting at high altitude and moving gradually toward Earth, as would be expected in a radial acceleration scenario. Instead, the data showed an increase in energy that started right in the middle of the radiation belts and gradually spread both inward and outward, implying a local acceleration source. The research shows this local energy comes from electromagnetic waves coursing through the belts, tapping energy from other particles residing in the same region of space.

"These new results go a long way toward answering the questions of where and how particles are accelerated to high energy," said Mona Kessel, Van Allen Probes program scientist in Washington. "One mission goal has been substantially addressed."

The challenge for scientists now is to determine which waves are at work. The Van Allen Probes, which are designed to measure and distinguish between many types of electromagnetic waves, will tackle this task, too.

The Johns Hopkins University Applied Physics Laboratory in Laurel, Md., built and operates the twin Van Allen Probes for NASA's Science Mission Directorate. The Van Allen Probes are the second mission in NASA's Living With a Star program, managed by NASA's Goddard Space Flight Center in Greenbelt, Md. The program explores aspects of the connected sun-Earth system that directly affect life and society.

Court stops scientists from publishing codes that could wirelessly lockpick Porsches

As Reported by the Verge: Three cryptography experts from UK and Dutch universities have cracked the codes used to start luxury cars such as Audis, Bentleys, Porsches, and Lamborghinis, knowledge that could allow anyone with the right tools to wirelessly lock-pick a $300,000 car. The researchers were preparing to publish a paper in August explaining the method used to penetrate Megamos Crypto, the algorithm-based system used to verify an owner's key. However, Volkswagen's parent, which owns the four brands, has secured an injunction against the University of Birmingham's Flavio Garcia from a UK court.

The scientists argued that "the public have a right to see weaknesses in security on which they rely exposed," but a judge ruled three weeks ago that "car crime will be facilitated" if the scientists publish the algorithm. Volkswagen had asked them to publish a redacted version without the codes, but they declined. Since then, the decision has become part of a wider discussion about car security.

It emerged in court that their complex mathematical investigation examined the software behind the code. It has been available on the internet since 2009.

Reviewing scientists said they had probably used a technique called "chip slicing" which involves analyzing a chip under a microscope and taking it to pieces and 'reverse engineering' or inferring the algorithm from the arrangement of the microscopic transistors on the chip itself – a process that costs around £50,000 ($77,000USD). The judgment was handed down three weeks ago without attracting any publicity, but has now become part of a wider discussion about car manufacturers' responsibilities relating to car security.

The scientists said they examined security on everything from Oyster cards to cars to enable manufacturers to identify weaknesses and improve on them.

The injunction is a temporary step in the case brought by Volkswagen, so it's possible the decision could be reversed. In the meantime, we'll be on the lookout for PhDs driving 911s.

Friday, July 26, 2013

GPS spoofing demonstrated on super-yacht in the Mediterranean

As reported by FoxNews: The world’s GPS system is vulnerable to hackers or terrorists who could use it to hijack ships -- even commercial airliners, according to a frightening new study that exposes a huge potential hole in national security.

Using a laptop, a small antenna and an electronic GPS “spoofer” built for $3,000, GPS expert Todd Humphreys and his team at the University of Texas took control of the sophisticated navigation system aboard an $80 million, 210-foot super-yacht in the Mediterranean Sea. “We injected our spoofing signals into its GPS antennas and we’re basically able to control its navigation system with our spoofing signals,” Humphreys told Fox News.

By feeding counterfeit radio signals to the yacht, the UT team was able to drive the ship far off course, steer it left and right, potentially take it into treacherous waters, even put it on a collision course with another ship. All the time, the ship’s GPS system reported the vessel was calmly moving in a straight line, along its intended course. No alarms, no indication that anything was amiss.

Capt. Andrew Schofield, who invited Humphreys and his team aboard to conduct the experiment told Fox News he and his crew were stunned by the results.

“Professor Humphreys and his team did a number of attacks and basically we on the bridge were absolutely unaware of any difference,” Schofield said. “I was gobsmacked -- but my entire deck team was similarly gobsmacked,” he told Fox News.

White Rose of Drachs
The possible consequences, according to Humphreys, are both ominous and far-reaching.

“For maritime traffic, there are big implications,” Humphreys told Fox News from the bridge of the White Rose of Drachs. “You’ve got 90 percent of the world’s cargo going across the seas. Imagine shutting down a port. Imagine running a ship aground. These are the kinds of implications we’re worried about.”

As the Costa Concordia tragically proved, a cruise ship off-course can have disastrous results. The Exxon Valdez was only narrowly off its intended track when it ran aground on Bligh Reef, spilling 11 million gallons of oil into Prince William Sound.

Humphreys told Fox News the easiest and most sinister “spoof” is to slowly slide a vessel onto a parallel course. Over time, the compass might read the same heading, but the ship could be far from where the crew thinks it is.

“You’re actually moving about a kilometer off of your intended track in a parallel line and you could be running aground instead of going through the proper channel,” Humphreys said.

And because aircraft have a similar navigation system to that aboard the White Rose of Drachs, Humphreys says a commercial airliner could be “spoofed” as well.

“Going after an expensive vessel on the seas and going after a commercial airliner has a lot of parallels,” he told Fox News.

The government is aware of this critical vulnerability. Last year, Fox News reported exclusively on a more primitive experiment Humphreys conducted using a small, unmanned drone. He was able to feed “spoofing” signals into the drone’s GPS, causing it to nearly fall out of the sky. As a result, Humphreys was called before Congress to testify, and also spoke with officials from the FAA, CIA and Pentagon.

This latest experiment takes Humphreys’ research to a whole new level.

“Before we couldn’t control the UAV. We could only push it off course. This time my students have designed a closed loop controller such that they can dictate the heading of this vessel even when the vessel wants to go a different direction,” Humphreys said.

Yet the Department of Homeland Security has -- according to Humphreys -- been “fumbling around in the dark” on GPS security, doing little to address the threat. Texas Congressman Mike McCaul, chairman of the Homeland Security Committee is incensed.

“It's a very serious homeland security issue that we've asked the secretary to review and look at and she's never responded to my requests,” McCaul told Fox News. “The department seems to be thumbing its nose at it, saying it has no jurisdiction over this issue and not really showing any interest in this issue at all.”

McCaul, along with Senators Coburn and Collins have asked the Government Accountability Office to look into what DHS is and isn’t doing to address this critical threat to national security.  A draft report is due in August, which could, depending on the results, trigger more Congressional hearings.
Meantime, Schofield is sounding a global alarm.

“People need to know this kind of thing is possible with a relatively small budget and they can with a very simple system steer the ship off-course -- without the Captain knowing,” he told Fox News.

Finding Mobile GPS Jammers using ad-hoc networks

GPS/GNSS jamming systems (sometimes referred to as personal privacy devices) are illegal, and for good reason - they're potentially dangerous.

As reported by InsideGNSS: GPS/GNSS technology constitutes a fundamental element for new intelligent transport systems (ITSs) and their applications, such as advanced driver assistance, dangerous goods tracking, and distance- based toll systems. Due to the weak strength of navigation signals from distant satellites, however, these applications are threatened by malicious as well as unintentional interference.

In particular, so-called in-car jammers — also known as “personal privacy devices” — represent a serious threat for GNSS-based systems and applications.
A common Chinese made GPS Jammer - illegal in the USA
purchasable in the UK, but illegal to use.

These jammers are cheap devices able to obscure, partially or totally, the navigation signals received not only by the operator’s vehicle but also by other receivers in the vicinity.

The introduction of standards for vehicular ad-hoc networks (VANETs) sometimes referred to Car2Car or V2V systems, enables the exchange of data regarding detected interference events. This data exchange can be used to enhance the awareness of interference sources, allowing their localization and mitigation, thus increasing the reliability of future ITSs.
Jamming devices could be thwarted using ad-hoc
vehicle networks - which are being developed in the USA
as well as the EU

GNSS Interference Detection and Localization 
Interest in developing GNSS interference detection and localization capabilities has increased steadily in the last few years. The first efforts in this direction have come for military applications, like the jammer detection and location (JLOC) system developed and propsed by Dr. Alison Brown with NAVSYS. This system provides situational awareness on GPS interference events to U.S. military personnel and predicts effects worldwide to enhance battlefield situational awareness and mission planning.

In the case of identified GPS threats, the system disseminates alerts and reports to subscribed JLOC users through the SIPRNet (Secure Internet Protocol Router Network), a system of interconnected computer networks used by the U.S. departments of defense and state to transmit classified information. The core element is the JLOC master station, operated by the U.S. National Geospatial-Intelligence Agency (NGA), which collects information on interference events through dedicated sensors incorporating GPS receivers. These sensors generate reports when they detect signal degradation as measured by carrier-to-noise ratio (C/N0) readings.

For the actual localization of the interference source, angle-of-arrival (AOA) information is collected from receivers capable of digital beam-forming, while time-difference-of-arrival (TDOA) measurements are computed with snapshots of data from multiple locations.

Further studies have been done to integrate mobile devices, such as cell phones, into the network of sensors. Also airborne sensors that can be carried on small unmanned aerial vehicles (UAVs) are envisaged for possible use in future jammer location systems.
Small UAV (drones) could be used to identify GPS jamming
sources in the USA

Interference monitoring and localization systems have been developed to protect safety critical aviation services as required by the International Civil Aviation Organization (ICAO) for GPS-based approach procedures.

In this application, location of interference sources is commonly based on direction-finding sensors. For example, in the United States the localization of interference is performed by the combined use of airborne (AIMDS), transportable (TIMDS), portable (PIMDS), handheld (HIMDS), and fixed (FIMDS) interference monitoring and detection systems. In Europe, similar systems are operated, such as the so-called GIMOS (GNSS Interference Monitoring System) in Germany.
A GBAS reference station outside of an airport.

The problem that can be caused for aviation by GPS jammers became very visible in November 2009 at the Newark Liberty International Airport (New York City). Without an appropriate interference localization system in place, it took more than three months to find the reason for periodic outages of the airport’s ground-based augmentation system (GBAS) reference stations: a GPS jammer transmitting from a vehicle passing near the airport. The airport eventually tackled the problem by making infrastructural changes, such as relocating the GBAS reference antennas over a wider area and enhancing interference detection and localization capabilities.

For maritime applications, the threat represented by jammers became evident in 2008, when the General Lighthouse Authorities of the United Kingdom and Ireland (GLA) conducted a series of sea-trials with the aim of characterizing the full effects of GPS jamming on safe navigation at sea. The test unveiled serious effects on GLA differential GPS (DGPS) reference stations and GPS receivers on ships, as well as radar systems using GPS as their time reference.

These results gave rise to the GAARDIAN/SENTINEL projects. The GAARDIAN project developed and deployed probe sensors at various locations around the United Kingdom and Ireland to continuously report on the integrity, continuity, accuracy, and reliability of GPS signals. The monitoring network was then further expanded by including the Ordnance Survey’s OS Net, consisting of more than 100 continuously operating GNSS receivers. This system bases detection of anomalies on a mask for C/N0 measurements.

The SENTINEL project later added interference localization capability to this network through the use of handheld GPS interference detection devices. AOA, TDOA, and differential-received-signal-strength (DRSS)–based geolocation are currently under investigation.

A down-to-earth alternative

Another way to cope with jammers is to deploy backup systems that do not depend on satellite signals, but rely on terrestrial signals instead. In America radio-navigation and air-traffic-control systems based on terrestrial beacons, which predate GPS, were supposed to be phased out by 2018 in favor of satellite-based alternatives, under a modernization program called NextGen, overseen by the Federal Aviation Administration (FAA). Switching to satellite-based air-traffic control would, for example, allow more direct routes and save fuel, because aircraft would no longer have to follow a 'wiggly' route from one ground-based beacon to another.

In a paper presented at the NAV10 conference in London in December, Mitch Narins, chief systems engineer at the FAA, and colleagues described the Newark jamming incident as “a valuable lesson” because it highlighted the risks of becoming too dependent on satellite-based systems that were vulnerable to disruption. Mr Narins and his team are now investigating whether the old-style terrestrial systems can be modernized and extended to provide a backup that could take over in the event of GPS failures. They expect to make their recommendations in 2013 or 2014, in time for implementation to begin in 2016.
An eLoran reference station

Elsewhere, eLoran is another non-satellite-based alternative which has many cheerleaders. It is an enhanced version of Loran-C, which is itself an improved version of the original Loran (“long-range navigation”) system developed in the 1940s. Once widely used in America, Japan and parts of Europe, Loran fell out of favor with the emergence of satellite-based systems. But its proponents have continued to develop the technology, and eLoran is now accurate to within 10 meters, which is comparable to GPS. “It is terrestrial as opposed to spaced-based, uses very high-powered signals rather than low-powered ones and it's very low frequency instead of high,” says Sally Basker, president of the International Loran Association. “All of which means its failure mechanisms are different to GPS and other satellite-navigation systems.”

Enthusiasm for eLoran is strongest in Britain, where the government awarded a 15-year contract in 2007 to develop eLoran for use by shipping in western Europe. A ministerial decision to move from the development to the operational phase is expected shortly. In the United States and Canada, however, Loran-C transmitters were switched off last year. After a long debate about the merits of keeping the system going, Barack Obama declared it outdated. The House of Representatives has given the Department of Homeland Security until April to decide whether a single, national GPS backup system is required. Which technology would be used to build such a system remains to be seen.

In a way, GPS has become a victim of its own success. Because it is used for such a wide range of civilian purposes, when somebody wishes to disable one GPS-based system, their actions can also disrupt other, unrelated systems. The benefits of satellite positioning are undeniable, and they are only likely to increase in future. But it is now clear that fully realizing those benefits depends on putting systems in place to mitigate against deliberate and accidental interference, and to provide an independent backup that does not rely on the delicate trilling of distant satellites. 

GPS jamming affects everyone, even the London Stock Exchange

As reported by The Economist: Every day for up to ten minutes near the London Stock Exchange, someone blocks signals from the global positioning system (GPS) network of satellites. Navigation systems in cars stop working and time-stamps on trades made in financial institutions can be affected. The incidents are not a cyber-attack by a foreign power, though. The most likely culprit, according to Charles Curry, whose firm Chronos Technology covertly monitors such events, is a delivery driver dodging his bosses’ attempts to track him.

The signals are weak. Mr Curry likens them to a 20-watt light bulb viewed from 12,000 miles (19,300 km). And the jammers are cheap: a driver can buy a dashboard model for about £50 ($78 USD). They are a growing menace. The bubbles of electromagnetic noise they create interfere with legitimate GPS users. They can disrupt civil aviation and kill mobile-phone signals, too. In America their sale and use is banned. In Britain they are illegal for civilians to use deliberately, but not, yet, to buy: Ofcom, a regulator, is mulling a ban. In recent years Australian officials have destroyed hundreds of jammers.

In the right (or wrong) hands, they are potential weapons. Britain’s armed services test the devices in the Brecon Beacons in Wales, a military training area. North Korea uses big lorry-mounted versions to block GPS signals in South Korea. Starting with a four-day burst in August 2010, the attacks, which come from three positions inside the North, have lengthened. In early 2012 they ran for 16 days, causing 1,016 aircraft and 254 ships to report disruption.
North Korea GPS jamming systems

Mr Curry worries that criminals or terrorists could knock out GPS for an entire city or shipping lane anywhere in a flash. Even without North Korean-sized contraptions, the jamming can be substantial. Suitcase-sized devices on sale on the internet claim a range of 300-1,000 metres.

Malfunctioning satellites and natural interference from solar activity have hit GPS signals and sent ships off course. David Last, a navigation expert, says an accidental power cut, perhaps caused by a jammer taken on board a car ferry, could cause a shipwreck. Generating a false signal—spoofing—is another threat. In December 2011 Iran said it had spoofed an American drone before capturing it (most experts dismiss the claim). So far effective spoofing seems confined to laboratories, but Mr Last says some governments are already taking countermeasures.

One solution is a different means of navigation. In April South Korea announced plans for a network of 43 eLoran (enhanced long-range navigation) ground-based radio towers, based on technology first used in the second world war. It uses a far stronger signal than GPS, and should give pilots and ships’ captains a safer alternative by 2016. With Chinese and Russian help, South Korea hopes to expand coverage across the region.

Britain’s General Lighthouse Authorities (GLA) are following suit with seven new eLoran stations. Martin Bransby, an engineer with the GLA, says this will replace visual navigation as the main backup for GPS. It will be working by mid-2014, and cost less than £700,000 ($1.08M USD); receivers cost £2,000 ($3,077 USD) per vessel. By 2019 coverage should reach all big British ports.

America’s military-research agency DARPA has an experimental “single-chip timing and inertial measurement unit” (TIMU). When finished, according to the project’s boss, Andrei Shkel, it will use tiny gyroscopes and accelerometers to track its position without using satellites or radio towers. America’s White Sands missile range in New Mexico is installing a “Non-GPS Based Positioning System”, using ground-based antennae to provide centimeter-level positioning over 2,500 square miles. In May the Canadian government said it would splash out on anti-jam upgrades for military aircraft.

A new version of the US air force’s bunker-busting bomb, designed in part to destroy Iranian nuclear facilities, includes technology to prevent defenders from blocking its satellite-based guidance systems. MBDA, a European missile firm, is working on similar lines.

But for many users, GPS and other space-based navigation systems—which include Russia’s GLONASS, China’s partly complete Beidou, and an as-yet unfinished project by the European Union (Galileo)—remain indispensable and ubiquitous. They are also vulnerable. For those whose lives or livelihoods depend on knowing where they are, more resilient substitutes cannot come fast enough.

Thursday, July 25, 2013

Hybrid location technologies: MEMS Sensor Positioning

Most smart phones include several MEMS sensors. The data they provide
helps make location possible when GPS signals are compromised.
As continued from our previous report: Many smart phones are equipped with sensors that track device orientation and movement to enable a host of applications, such as gaming and compasses (Table 6). These sensors usually include microelectromechanical systems (MEMS).

For example, accelerometers measure acceleration based on user movement. Generally, a three-axis accelerometer measures the change in user velocity position in a variety of cases, such as walking, running, falling, and vibration.

Gyroscopes measure rotational velocity. They also are implemented across three axes. Gyroscope measurements provide orientation. A combination of accelerometer and gyroscope measurements in three dimensions can be used to continuously track user position.

Magnetometers measure the earth’s magnetic field as well as any ambient magnetic influences. They are used for mapping and compass functions (potentially in conjunction with accelerometers). And, barometers measure the altitude based on air pressure changes and can be used to find a user’s position while moving up in altitude (Fig. 4).

Physical readings from the sensors are typically sent to the inertial measurement unit (IMU), which collects data from the inertial sensors, formats them, and delivers them to the sensor location subsystem—the inertial navigation solution (INS). Yet there’s a key difference in the positioning technique used by the INS compared to other location methods.

A-GNSS and Wi-Fi positioning and cellular positioning methods feature an absolute position computation process. The INS uses dead reckoning. It’s given a starting position (perhaps from an A-GNSS fix) and then uses sensor data such as speeds and angular direction to advance the position over time. Eventually, the uncertainties in the reported sensor data add up, and a new, accurate reference position is required to start the dead reckoning process over.

While GPS, Wi-Fi, and cellular technologies provide the user’s position on the map, sensors can provide an idea of how the mobile device itself is moving—whether it’s being turned, set on a table, or thrown. This fine-grade information can be very useful for enabling applications such as gaming. It also presents a challenge.

If purely position calculation is of interest, then the positioning engine must be able to intelligently filter out extraneous effects such as the rhythmic motions of walking or running and holding the handset in different positions while talking. Different people have different usage profiles, so the sensor’s positioning engine must be able to robustly handle a variety of different scenarios.

DARPA Seeks to Eliminate GPS Dependence

As reported by GPSWorld: Call it irony, poetic justice, or just the nature of the beast. The same impulse that led to the invention of GPS now has engendered a drive to beget non-GPS.

In the 1970s, the U.S. military began putting together a program “to drop five bombs in the same hole.” The program office, to the wall of which that mission statement was tacked, went on to develop the first satellite navigation positioning system: GPS. In 2012, the U.S. Defense Advanced Research Projects Agency (DARPA) declared that this system no longer sufficed for reliable delivery of precision munitions under every circumstance.

“More than 98 percent of the missiles currently in the U.S. arsenal have mission durations of less than 20 minutes, and today, almost all of these missions are critically dependent on GPS for achieving the required level of delivery accuracy,” a communiqué stated.

Because of vulnerability to jamming, spoofing, and other intentional or unintentional modifications of position, orientation, and time information, the agency has put forth a new goal “to completely eliminate dependence on GPS or any other external signals during the mission and rely solely on self-contained solutions such as inertial navigation,” which is immune to such extrinsic forces.

The Chip-Scale Combinatorial Atomic Navigator (C-SCAN) program has made 10 exploratory grants to investigate and develop this concept, to large corporations, a small start-up, national labs, and academic groups. Only one has been announced, by contracting agent Wright Patterson Air Force Base, to AOSense. DARPA wishes to emphasize that this is a sample of what is happening in C-SCAN, and should not been viewed by readers as the only technical approach paving the way.

The company, located in Sunnyvale, California, has gotten busy building an experimental navigation-system-on-a-chip that combines traditional, solid-state, and atomic inertial guidance technology. Their goal: create a sensor on a chip that works reliably, without drift, over considerable distances for at least 20 minutes.
AOSense is exploring how to shrink and fabricate atomic sensors together with high-performance solid-state inertial sensors. DARPA hopes the C-SCAN program will lead to a breed of inertial microsystems, with a wider range of operating conditions and greater immunity to the environment, reduced start-up time, increased sensitivity, and improved bias and scale factor stability. Oh, and not cost too awful much per piece.

Another project at Northrop Grumman seeks to develop a  micro-gyro for personal and unmanned vehicle navigation.

Despite impressive micro-PNT work to date, current mechanisms remain complex, bulky, power-hungry — and pricey. They have limited resolution and poor long-term stability. Alternative forms give excellent resolution and bias stability, but are limited in bandwidth and generally do not allow high-frequency measurements.

Make no mistake, however. Yankee (and whatever other forms that can be brought to bear) ingenuity will, eventually, win the day. Where then will GNSS find itself?

Wednesday, July 24, 2013

NTSB calls for wireless technology to let all vehicles 'talk' to each other

As reported by NBC: Federal safety authorities Tuesday called for all U.S. cars, trucks and buses to come equipped with technology that would allow them to "talk" to one another to help avoid accidents.

The proposal was one of three the National Transportation Safety Board (NTSB) made Tuesday in its investigation of two school bus accidents last year. The main focus was an accident near Chesterfield, N.J., that killed an 11-year-old girl, but the board also looked at evidence from a similar accident in Port St. Lucie, Fla., that also killed a student. In both accidents, the school buses collided with trucks at intersections.

In a summary report, the board recommended that the National Highway Traffic Safety Administration (NHTSA) develop standards for "connected-vehicle technology" — wireless components that would let vehicles communicate on the road. The full final report is expected in about three weeks.

With those standards in place, "NHTSA can then require this technology to be installed on all highway vehicles," Deborah Hersman, chairman of the NTSB, said at the board's meeting Tuesday. "This technology more than anything else holds great promise to protect lives and prevent injuries."

The Alliance of Automobile Manufacturers, the trade group for most of the major automakers — which is working with the NHTSA on research and development of connected-vehicle technology — didn't immediately respond to a request for comment.

But in testimony before the Senate Transportation Committee in May, Mitch Bainwol, the alliance's president and chief executive, raised doubts that such systems could be feasible in the near term.
Aftermarket component systems would need to be overhauled, a patchwork of state and federal laws would have to be unified and legal questions of liability surrounding operating cars with automated systems would have to be hashed out, he said.

"The question of who is responsible — when (and) for what — will need to be addressed," Bainwol said.
Last August, the NHTSA began conducting a yearlong study of 3,000 connected vehicles in Ann Arbor, Mich., using WiFi-like components that send electronic data messages back and forth and translate the data into a hazard warnings for the drivers. The test is focusing on safety at intersections, lane changes and rear-end accidents involving vehicles stopped at intersections.

"Vehicle-to-vehicle communication has the potential to be the ultimate game-changer in roadway safety — but we need to understand how to apply the technology in an effective way in the real world," NHTSA Administrator David Strickland said when the test was launched.

Regarding the two school bus crashes, the NTSB also recommended tougher qualifications for agencies that oversee the medical certification of commercial drivers. The summary report found that the driver of the bus in the New Jersey crash was fatigued and was using sedatives, and it said he likely wouldn't have been issued a license had he disclosed all the medications he was taking.

In an animated reconstruction of the New Jersey crash, NTSB investigators depicted the truck's speeding into the intersection just as the school bus was leaving it. The reconstruction shows the truck ramming into the left rear side of the bus, which spins off the road.

The truck driver was speeding and was carrying an overweight load in a truck that had defective brakes, the NTSB said.

And the NTSB also looked at the effectiveness of the seat belts on the bus in New Jersey — one of only six states that require school buses to have them.

The board said seat belts and shoulder belts would have helped to reduce flailing injuries, but it stopped short of recommending their mandatory use nationwide.

Instead, it recommended that school districts offer training to bus drivers, students and parents to drive home "the importance of wearing seat belts" in the states that do require them: California, Florida, Louisiana, New Jersey, New York and Texas.

The National Association for Pupil Transportation said it was eager to work with the NTSB and the NHTSA "to evaluate the practicability of implementing the recommendations that have been offered today."

Lockheed Martin Prototype to Help Prep for GPS III Launch

As reported by GPSWorld: Lockheed Martin has delivered a full-sized, functional prototype of the next-generation GPS satellite to Cape Canaveral Air Force Station to test facilities and pre-launch processes in advance of the arrival of the first GPS III flight satellite.

The GPS III Non-Flight Satellite Testbed (GNST) arrived at the Cape on July 19 to begin to dry run launch-base space-vehicle processing activities and other testing that future flight GPS III satellites will undergo. The first flight GPS III satellite is expected to arrive at the Cape in 2014, ready for launch by the U.S. Air Force in 2015.

The GNST arrived at the Cape by Air Force C-17 aircraft from Buckley Air Force Base near Lockheed Martin’s GPS III Processing Facility (GPF) in Denver, Colorado. Prior to shipment, the GNST was developed and then completed a series of high-fidelity activities to pathfind the integration, test and environmental checkout that all production GPS III satellites undergo at Lockheed Martin’s new satellite manufacturing facility.

An innovative investment by the Air Force under the original GPS III development contract, the GNST has helped to identify and resolve development issues prior to integration and test of the first GPS III flight space vehicle (SV 01).  Following the Air Force’s rigorous “back-to-basics” acquisition approach, the GNST has gone through the development, test and production process for the GPS III program first, significantly reducing risk for the flight vehicles, improving production predictability, increasing mission assurance and lowering overall program costs.

“We call the GNST a ‘pathfinder’ because it has truly blazed the trail for every one of our GPS III processes from initial development, production, integration and test, and now pre-launch activities,” explained Keoki Jackson, vice president for Lockheed Martin’s Navigation Systems mission area. “All future GPS III satellites will follow this same path, so the GNST was a smart initiative to help us discover and resolve any issues in advance, implement production efficiencies, and ultimately save a tremendous amount of time and money in the long run.”

GPS III is a critically important program for the Air Force, affordably replacing aging GPS satellites in orbit, while improving capability to meet the evolving demands of military, commercial and civilian users. GPS III satellites will deliver three times better accuracy, include enhancements which extend spacecraft life 25 percent further than the prior GPS block, and a new civil signal designed to be interoperable with international global navigation satellite systems.

Lockheed Martin is currently under contract for production of the first four GPS III satellites (SV 01-04), and has received advanced procurement funding for long-lead components for the fifth, sixth, seventh and eighth satellites

Tuesday, July 23, 2013

Adaptive Filtering for Errant GPS Data in Smartphone and Vehicle Tracking Systems

loop of errant position data - only about
5.2km was actually traveled.
The route shown to the left is for a pedometer application on my iPhone; one of the many free applications available.  You'll note a loop in the middle of the run - where in fact there was no actual loop; I followed streets and highways and took the same path back that I took out.  When I posted the data on Facebook, my friends and family congratulated me on such a long distance over a short time period - I had to explain that the data wasn't accurate, which I only knew from experience on this route - and by looking closer at the actual trail that the application created for me on a separate page.

So what happened?  GPS data (which is a key source of how the pedometer generates it's data) from time to time can lose accuracy - it's a fact of life; nothing is infallible.  This can be attributed to several potential factors: inadvertent or intentional signal jamming, loss of signal strength in heavy tree foliage, multipathing, an impaired view of the sky combined with a poor satellite constellation, ionospheric interference, space weather interference or signal degredation, GNSS systemic issues, etc.

This reminded me of the reason we developed adaptive filtering processes into our vehicle tracking software.

Big Data - Real-time position data
Smartphone and vehicle tracking systems are a kind of 'Big Data' system that is continuously absorbing position data from the field - pre-processing some of the data, but storing it away for use and forwarding to customers; either in near-real-time, or at a later date.  Some errant data can be identified and eliminated immediately, but most data must be evaluated later for cohesiveness.  Data errors are not always multidimensional: in some cases all but one particular portion of the data is correct.

Adaptive GPS Filtering
A position taken under an overpass inadvertently increased
the estimated speed of the vehicle to 99MPH, which triggered
an over-speed alert, which in turn warranted an investigation.
The driver was cleared of any wrong doing after the analysis.
By looking at moving 'windows' of patterned data, the system can evaluate positions and select those that seem to be out of sync with prior patterns, by evaluating significant speed deviation, sudden direction changes, sudden changes in available satellites for a location calculation and position data that appears 'out of place'; or combinations of the prior conditions.  The larger the data-set to work from, especially when looking backward and forward, the better these types of analyses perform - and the more likely they are to find and remove the errant data while leaving valid data in-place.

Endpoints and window size of data
Errant data at the beginning or end of a reported sequence of data can be more difficult to detect - but one easy way to fix that is by changing the time window; by choosing an earlier start or stop time for the report.  As the window narrows, this gets more and more difficult to determine - such as in instantaneous alert reporting - i.e. over-speed alerts.

Fleet Managers - the human brain as a Big Data Engine
In a prior report we discussed how fleet managers can act a a 'Big Data' Engine, evaluating data in order to determine if it's valid, and to give it proper meaning.  In the above example, it was difficult to tell from the position report or the over-speed alert if this was an actual violation by the driver or not. Though positions prior to and after the report looked normal, it was possible for the driver to have increased their speed long enough to reach the alert trip - but by pairing the data with the satellite map data, we were able to determine that there was an impaired view of the sky, and possible multipathing - eliminating the point as a possible traffic violation.  This kind of analysis would be difficult or impossible with today's technology; there is still a place for humans as part of the critical evaluation of events.

In the future, use of inertial measurement unit technology will be able to help 'fix' the problem at the source by providing an estimate that the GPS signal can corroborate with or can identify as 'challengable'.

In the original example, it appears that there is an intermittent wide-band jamming source in the area that I happened to be traveling.

Hybrid location technologies: indoor/outdoor GPS/WiFi

As continued from our previous report: Smart phones commonly support Wi-Fi to connect to the Internet, a feature encouraged by network operators to offload the large amounts of cellular data a standard smart phone generates. In addition, the properties of the Wi-Fi technology can be exploited for location positioning, or combined with an existing GPS tracking system it can be used as a hybrid positioning system.

There are many different proprietary implementations of Wi-Fi positioning, including fingerprinting techniques, which take advantage of environments with high Wi-Fi access point (AP) density such as cities and buildings.

First, the device scans and sends information about the visible Wi-Fi APs—generally the strongest APs are rated in terms of received signal. Second, this information is reported to a server on the network. The server houses a database of APs associated with geo tags and other markers. A fingerprinting algorithm is applied to the input from the handset, which then provides an estimate of the mobile’s position.

The information doesn’t always have to be provided to the network. Instead, the network may provide a subset of its central database to the handset, which then can run the fingerprinting algorithm itself. The fingerprinting algorithm can only work if a sufficiently advanced central database of Wi-Fi APs for the location of interest is available. This database is created by:

  • Wardriving: Driving (or walking) in specific areas and using high-grade receivers to collect visible Wi-Fi AP data.
  • Crowd sourcing: Having a smart phone constantly report observed Wi-Fi APs along with a GPS location (if available) to location servers

In some cases the handsets are used to augment the database of Wi-Fi reference points; reporting or augmenting the position data for the device or handset that is mobile - while also 'wardriving' - reporting mobile position data and AP updates at the same time.  When done with the users knowlege, this can be helpful - but when done as 'secret' tracking then this can be potentially injurious to the user.