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GPS Satellite Blackout: Overview, Reasons, and Results of GPS Blackout

written by: •edited by: Heather Marie Kosur•updated: 5/19/2011

GPS satellite blackouts are much rarer than in the past owing to the updated fast-paced technology. Still, people experience GPS blackouts sometimes. This article explains GPS satellite blackout while offering a take on GAO’s prediction of a massive GPS Satellite Blackout in 2010.

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    Our Dependency on GPS Technology

    Fig 1 GNSS  A GPS device relies on a network of satellites that send it information about the device’s whereabouts in the form of radio signals. The network of satellites that is designed to collect and send the required information is generally coined GNSS (Global Navigation Satellite Systems). Every GPS device or earth-based GPS server contains a GNSS receiver that accepts the different signals and computes them to provide you with accurate navigational information. The joint efforts of GNSS in earth’s orbit and the GNSS receiver in your GPS device help in determining and enhancing the accuracy of the GPS device.

    GPS technology is heavily used in almost all fields of life, from normal day-to-day driving to hiking to skiing to cruises and to space shuttles and many more. Although the ships, submarines, airplanes, and shuttles also use radars, they also consider GPS technology to know where exactly to anchor or land. People across the world are so used to GPS technology that they cannot decide what do to in the event of a GPS Satellite blackout.

    A GPS blackout causes your GPS device to fail for a few seconds, minutes, or even hours. This happens when the GPS receiver fails to receive the signals sent by the GNSS or is unable to receive it completely. Normally, a GPS receiver needs information about the longitude, latitude, height, and time when the signal was released from the satellites revolving around the planet Earth. Even if just one piece is missing, your GPS device either fails to show up any information or provides you with error.

    IMPACT OF 1965 POWER FAILURE: If you remember the power failure of 1965, you might also remember how scary it was. People were stuck where they were, not for one or two hours but for almost twelve hours, all because the earth-based GPS were down due to the power failure and they could not decide which direction to head for. Although technology has advanced many folds since then, there still are GPS blackouts every now and then anywhere on the planet.

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    Major Reasons behind GPS Satellite Blackout

    To understand the reason for blackouts, you need to know the basics of GPS navigation. You might have experienced your GPS device not working at some particular locations. But, when you change the location, it starts working again (although it takes some time to restart). The major reason behind this is that the GNSS satellites send in the information in form of radio signals.

    Radio signals do not have powerful penetration strength. This means that the radio signals sent by GNSS satellites are not able to get through any concrete building, a solid Iron Gate, deep tunnels, or sometimes even in the elevator. This is why your GPS device cannot receive the signals when any obstruction comes between the satellite and the GPS device. These obstructions can be either in space (objects in space like rocks, dust clouds, and other similar obstacles), in Earth’s atmosphere (mostly dust particles and flying objects including airplanes), and, finally, on the surface (skyscrapers, monuments, or anything else that stops the signal from moving ahead).

    In addition, the radio signals lose strength as they travel. Although the GNSS sends radio signals strong enough to reach your device, they have to pass through the vacuum (space) and different layers of Earth’s atmosphere. Depending upon your location, the GNSS signals may fade out. For example, if you are deep inside the ocean, you may find low strength signals that may make it difficult for the receiver inside your GPS machine to receive them, and your GPS device therefore shows you nothing.

    Even with the above mentioned problems, GPS are being used for a variety of purposes: location, navigation, mapping, tracking, and timing. Other than the normal people; the military, mining, shuttles, and many more sectors are shifting their operations to GPS-based devices. The following section shows why GPS is so successful even with the lingering possibility of GPS Satellite Blackout.

    Tip: It is always better to check the type of receiver inside your GPS device. A cheap receiver will give you more problems than a powerful GNSS receiver.

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    Getting Past the Hurdles of GPS Satellite Blackout

    As mentioned earlier, your GPS device relies on a GNSS to receive signals, to interpret them, and to offer you with the desired information. At the moment, there are more than thirty-one satellites that cater to the GPS networks across the planet.

    In short, this means that your GPS device receives signals from different satellites located at different places with thousands of atomic clocks so as to offer signals from different angles. The NAVSTAR (the US GNSS) takes care that it sends signals from different angles so that even if a particular signal is stopped or if its path is altered, your GNSS receiver still gets the information from other angles. This reduces the probability of GPS satellite blackout to a great extent.

    Besides, the technology has progressed so much that you have powerful and smart GNSS receivers that are intelligent enough to study even the weakest signals to offer proper accuracy of GPS. In many cases, smart GNSS receivers also make up for distorted signals to provide you with the required information.

    In addition, there are several ground stations that keep a close watch on the position and functionality of satellites. These ground stations are also responsible for reporting problems with satellite transmissions and getting them fixed almost instantly, leading to uninterrupted signal reception and minimum GPS blackout.

    The next section is a briefing over the possibility of a major GPS Satellite Blackout in 2010.

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    The 2010 GPS Satellite Blackout – Myth or Reality

    News about the possible failure of the entire GPS system in the year 2010 is a big concern for technology addicts who just cannot survive without their GPS devices. They are not sure if the news is true or one of the many rumors related to satellites as in past. Let us check out what is it all about.

    According to the Government Accountability Office (GAO), because of the mismanagement and misuse of funds by the US Air Force, the NAVSTAR may paralyze next year, leading to a massive GPS Satellite blackout. The GAO says that the US Air Force has been slow in implementing its plans of replacing older satellites with new ones. It further says that as soon as the old satellites start failing, the entire GPS constellation will fail. According to the GAO, if the Air Force is not able to meet its goal of deploying new satellites, most regions will not be able to access GPS related services.

    However, if you notice, the statement from GAO still contains the phrase: “If the US Air Force fails…" As far as we know, the US Air Force is among the best and dedicated entity that is working towards the goal and most probably WILL achieve the goals to keep NAVSTAR up and running.

    Other than the US, many other countries are already getting their own GNSS ready for full functionality. GLONASS from Russia is just a few steps away from becoming fully functional. Similarly, China’s COMPASS and Europe’s Galileo are being assembled at a fast pace.

    The bottom line is that there is no question of NAVSTAR (US) failing, and, even if some satellites are left out, relays will be used among the different GNSS so that there is no massive GPS Satellite Blackout anywhere on the planet.

Essentials of GPS

This series on GPS aims to offer you details on the essentials of GPS. It covers the GPS signal strength, measuring GPS accuracy, and factors that affect the GPS accuracy. Check these articles and feel free to ask further information on essentials of GPS.
  1. Enhancing the Code to Measure GPS Signal Strength – Essentials of GPS
  2. How GPS Satellite Detection Sensitivity Affects the Accuracy of GPS
  3. GPS Satellite Blackout: Overview, Reasons, and Results of GPS Blackout
  4. How GPS-Enabled Remote Security Alarms Work
  5. Cellphones, FM, Internet, and GPS – the Radio World in Communication and Broadcasting