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Tuesday, June 11, 2013

Detecting GPS/GNSS Spoofing using antenna articulation

There is a recent article out by Mark L. Psiaki, Steven P. Powell, and Brady W. O'Hanlon on GNSS spoofing detection, related to the specific possibility that the drone recovered by Iran was potentially spoofed into landing, allowing them to capture the drone.  The article also lays out a technological solution on how to prevent that from happening in the future; whether or not it actually happened in Iran which is still a matter of conjecture.  Technology simulating the spoofing capability was tested against a UAV helicopter (while hovering) in White Sands for simulation - but so was the possible solution.

The potential solution involved (in the prototype) articulating the GPS/GNSS antenna in a predefined motion that the spoofing system could not detect - allowing the augmented GPS/GNSS system to determine when the signal they were receiving was valid or not, by looking for regular perturbations of the signal caused by the induced motion. This appeared (according to the writers) to be an excellent way to detect GPS/GNSS spoofing in near-real-time.

While in the USA commercial and consumer tracking markets, we're more likely to run into low cost GPS/GNSS jamming systems, spoofing will likely be trending up in the near future.  What the military is encountering today, we in the commercial and consumer GPS markets are likely to encounter tomorrow.  As we continue to work with potential GPS/GNSS vendors we'll be asking about the future ability to include electronically synthesized antenna motion, as well as additional processing power for software radio based spoofing solutions; as well as the possible integration of inertial measurement unit (IMU) technology to help provide navigation holdover when the GPS/GNSS signal cannot be adequately discerned, or it is determined to be potentially inaccurate.  This may also be a practical solution for areas where electronic jamming is not the problem, but natural interference or degradation of the signal (such as obstructions in parking garages, tunnels, or due to multipath signals) is the culprit.

Monday, June 10, 2013

Setting up Idle Alerts and Reporting to help drive fleet costs down

Excessive idling can cost thousands a year in fuel and maintenance costs.

America's fleet of about 500,000 long-haul trucks consume over a billion gallons of diesel fuel each year.  The trucking industry has analyzed the impact of idling on engines, both in terms of maintenance and engine wear costs.  Long-duration idling causes more oil and oil filter deterioration and increases the need for more oil and filter changes.  Similarly the longer the idling time, the sooner the engine itself will need to be rebuilt. 

The trucking industry estimates that long duration idling costs the truck owners $1.13 per active vehicle per day, just in oil and maintenance costs.  Excessive idling fuel costs vary from vehicle to vehicle, but estimates for small vehicles (Ford Focus for example) is in the range of 2 liters or 0.32 gallons per idle hour.  For heavy trucks (Ford F-350), the estimate is closer to 6.8 liters or 1.08 gallons per idle hour.  A study by the Texas Transport Institute indicated that Semi trucks idle their engines for 6 to 10 hours a day outside of normal travel.  Estimated total annual idling time was in the range of 1,500-3,000 hours per truck per year.  Using the estimated average diesel fuel costs for 2013 to be $3.88 per gallon of fuel, this would cost the average semi-driver between $5,820-$11,640 per year.  Across the trucking industry this represents about $2.91B - $5.82B in potential lost revenue annually.

According to the US Department of Transportation there were an estimated 254,212,610 registered passenger vehicles in the US in 2009.  Using a NOx estimated Emissions calculation of 5 minutes per day per vehicle (on average) would indicate emissions of 127 tons/day.  It's estimated that 23 tons/day of NOx are emitted in the major metropolitan areas in Texas alone due to extended truck idling, so vehicle idling is a major contributor to the overall emissions inventory of the US.  Using vehicle tracking systems and setting up in-house idling policies can help to measure and reduce idling costs both in terms of costs to the owner or company, as well as the cost to the environment.


Setting up email alerts to measure when a vehicle has been idling for a minimum period of time, can help act as a reminder that the driver has exceeded his minimum idling time frame - and can help change idling behavior.

Additional alerts can be sent after the initial idle alert to indicate excessive idling - which can be evaluated by managers; to determine if the situation is an exception to the standard idling rules.


Managers can also run monthly or bi-monthly idling reports to verify that idling is reduced, and to carefully measure what current idling rates are costing the company - or how much adherence policies are doing to help reduce costs.

Several companies utilizing vehicle tracking systems have indicated that in actual practice, that the cost of implementing a GPS based vehicle tracking system can be paid for just on the savings of reduced fleet idling alone - even without adding in additional savings in insurance and reduced liability, reduced fuel usage, routing, safety, delivery verification, and driver productivity provided by the system.

Friday, June 7, 2013

How Space weather can affect GPS satellite performance



Space weather is the study of changing environmental conditions in near-Earth space, or the space from the Sun's atmosphere to the Earth's atmosphere.  It is a separate concept from weather within the Earth's atmosphere.


One of the events of most concern regarding space weather are coronal mass ejections (CMEs) from the Sun, which are considered separate events from solar flares - though the two appear to be related.  CME's typically bring a shock wave of solar energetic particles to the Earth's atmosphere, causing a visual effect near the poles commonly called the 'aurora borealis'.  Other effects include geomagnetic storms, radio blackouts, and electrical line overloads which can lead to cascading power outages, as well as satellite outages. Geomagnetic storms are categorized from G1 (minor) to G5 (extreme). 


The ionosphere bends radio waves in the same manner that water in a swimming pool bends visible light.  The Global Positioning System (GPS) uses signals at 1575.42MHz (L1) and 1227.6 MHz (L2) which can be distorted by a disturbed ionosphere and a receiver computes an erroneous position or fails to compute any position. Because the GPS signals are used by a wide range of applications, any space weather event which makes the GPS signal unreliable can have a significant impact on society. For example the Wide Area Augmentation System (WAAS) is used as a precision navigation and tracking tool for commercial aviation, personal tracking and commercial fleets in North America. It is disabled by most major space weather events. In some cases WAAS is disabled for minutes, but it can be disabled for days depending on the severity of the storm. Major space weather events can push the disturbed polar ionosphere 10° to 30° of latitude toward the equator and can cause large ionospheric gradients (changes in density over distance of 100's of km) at mid and low latitude. All of these factors can significantly distort GPS signals.

Wednesday, June 5, 2013

GPS Modernization Video

A great 7 minute video summary of everything that the US GPS system provides to the public, for civil, economic, and defense activity throughout the world.

The overview includes its use for aircraft and ship navigation, global financial transactions, precision agriculture, weather forecasting  disaster relief, vehicle tracking and navigation, as well as its use in Smartphones.

USA Air Force studying lower cost solutions for the GPS satellite constellation

With the sequester in full swing all of the government agencies are looking for potential cost savings - and the Air force's deployment of the new GPS III satellite systems are officially part of that cost savings analysis.

GPS III satellites, which are scheduled to replace the aging satellites currently in orbit are still being considered as part of the plan, but so are 'downsized' versions of the satellites - so called NavSats (also referred to as Spartan sats or NibbleSats).  More of these satellites could be deployed to help provide fewer 'minutes of outages per day' (for areas that are 'sky impaired') than the current constellation, while giving up some of the more advanced features of the GPS III - such as the Nuclear Detonation Detection System payload (NDS) that requires significant power and shielding considerations.  Reduced power and shielding, as well as some feature reductions combined with design modernization for overall weight reduction, can allow for multiple satellites to be launched into orbit at the same time - further reducing overall budget costs.  Dual satellite launches for the GPS III are being considered, but launching of four of the NavSats at a time would provide even more efficiency.  Developing the capability for Earth based launch systems for multiple GPS satellites would also be helpful to future multi-satellite missions for the Moon, or for Mars missions.

Including some additional technological design improvements to help reduce weight, design, and operational costs (such as the use of lithium ion batteries and more efficient solar panel designs, as well as modernization for reduced heat rejection), the NavSat systems could reduce on-orbit costs to as much as 1/4 of the cost of the GPSIII (from an estimated $450 million to $110 million).  This additional savings, and the potential to increase the number of working satellites in orbit (from 24 to a proposed 33) would reduce costs and increase satellite visibility for regions such as Afghanistan where some mountainous areas include masking angles of up to 60 degrees.  With 24 satellites at 60 degrees of masking, outages can be as high as 6 hours per day - but with 33 satellites, no outages are calculated to occur until you lose one or two satellites - and those outages last about an hour or less.

Tuesday, June 4, 2013

India Satellite Navigation Center Inaugurated

The Indian Space Research Organization (ISRO) Navigation Centre was Inaugurated May 28 2013 in Byalalu Bangalore, India.

Unlike the US Global Positioning System (GPS) which uses a low earth orbit system to cover the globe, the IRNSS coverage area is restricted to about 1,500km-2,000km around the Indian land-mass.  The system which is controlled by the Indian government was developed because of the concern that many GNSS, GPS system services may not be provided in possible future 'hostilities'.

The system is planned to use 7 total satellites with 3 of these satellites in geostationary orbit and the other four in an inclined geosynchronous orbit - along with a network of 21 terrestrial ranging stations located around India.

The first satellite, IRNSS-1A was scheduled for launch on June 12, but has been delayed for at least two weeks.  The satellite is planned to be launched from Satish Dhawan Space Centre in Sriharikota, Andhra Pradesh - located on an island about 80km north of Chennai near the Bay of Bengal.

The ISRO Navigation Centre (INC) was inaugurated by V. Narayanasamy, Minister of State in the Indian Prime Minister's office, and a member of Parliament.

Monday, June 3, 2013

Future 5G wireless

Samsung is testing 5G wireless technology in New York, sending and receiving more than a gigabit of data per second up to about 2 km - and possibly tens of gigabits per second at shorter distances.  The current design incorporates 64 antennas, which can be used to dynamically shape how the signals are divided up as well as providing directional transmissions.

Reaching these transmission speeds for stationary systems is one thing; getting them to work for mobile handsets is another - which is why several experts have been skeptical of their claims.  However, it appears that they have the system working for mobile speeds of about 8KM per hour (about 5MPH).  Additional testing has shown that the link could reach 200 meters even when there is no direct line-of-site between the mobile and tower.

Using the new technology - where a transmitter is mounted on an outside wall at the third-floor level of an 11-story concrete building, and with the receiver moving, they were able to deliver error free data at 256 Mbits per second, and nominal errors at 512 Mbits per second - where the maximum theoretical for 4G LTE would be about 75 MBits per second (under similar conditions); a 3-6 fold increase in data transmission speeds.

Transmitting and receiving data at these high rates have several challenges - including building obstructions or natural atmospheric phenomenon such as rain or fog.  Using the 64 antennas and rapidly switching between them to get the clearest signal is referred to as 'beam forming', and is mentioned as part of the Samsung patent filing.

Though Samsung is working on this technology, only the International Telecommunications Union can formally declare a new standard.  Nevertheless, companies like Samsung are competing heavily to help influence future communication standards.  Such new speeds will be required for the anticipated heavy influx of real-time multi-stream video and data that mobile devices will be expected to handle in the future.