Coordinates : A resource on positioning, navigation and beyond » GNSS http://mycoordinates.org Tue, 07 Feb 2012 16:28:27 +0000 en hourly 1 http://wordpress.org/?v=3.1.1 It cannot go on forever… We have to find a solution! http://mycoordinates.org/it-cannot-go-on-forever%e2%80%a6-we-have-to-find-a-solution/ http://mycoordinates.org/it-cannot-go-on-forever%e2%80%a6-we-have-to-find-a-solution/#comments Fri, 20 Jan 2012 15:58:50 +0000 admin http://mycoordinates.org/?p=12736 The discussions in the United States among LightSquared, the Federal Communications Commission (FCC), the Global Positioning System (GPS) industry, Department of Defence (DoD), Department of Transportation (DoT) and users about the division of spectrum in the L-band should not be seen as just an internal US affair. The strength of both the camps, Telecom providers and the GPS industry indicate that this battle may easily expand to other parts of the world. For many, this battle was a surprise, particularly for a peaceful world like navigation, where discussions are more gentlemen like and either focused on which GNSS systems is the best, or on the backup of GNSS which is so vulnerable and where society cannot function anymore without GNSS. All this changed abruptly when LightSquared published plans to install 40,000 transmitters in a band adjacent to L1 band used by GPS. This led to numerous protests in the GPS industry and among its users as what has been published in many magazines. It is for us to see whether it is telecom versus GPS, or is there a sensible cooperation in reach?]]> http://mycoordinates.org/it-cannot-go-on-forever%e2%80%a6-we-have-to-find-a-solution/feed/ 0 Receiver designers should be prepared for a more complicated spectral environment http://mycoordinates.org/lightsquared-and-gps-3/ http://mycoordinates.org/lightsquared-and-gps-3/#comments Sun, 18 Dec 2011 17:11:10 +0000 admin http://mycoordinates.org/?p=12573 The bottom line is that the LightSquared signals interfere with GPS, and LightSquared should not be allowed to proceed until the interference problems are resolved. To understand this perspective, some background is useful. The spectrum allocated to GPS for its L1 signal is from 1559 MHz to 1591 MHZ. This spectrum is shared by other Global Navigation Satellite Systems such as the EU’s Galileo, China’s Compass, and shortly also by Russia’s GLONASS, which uses the 1598 MHz to 1605 MHz band for its present signals. Basically, GNSS signals occupy the 1559 MHz – 1605 MHz band.]]> http://mycoordinates.org/lightsquared-and-gps-3/feed/ 0 Lightsquared and GPS http://mycoordinates.org/lightsquared-and-gps-2/ http://mycoordinates.org/lightsquared-and-gps-2/#comments Tue, 22 Nov 2011 18:51:31 +0000 admin http://mycoordinates.org/?p=12343 LightSquared is a gem! I am not only talking about its nationwide high-speed 4G capabilities and that it will be a boost to our lagging IT industry which has fallen behind 18 other nations. I am focusing on how it can beautifully complement high precision applications of GPS. It is a gem for GPS high precision users and for RTK.]]> http://mycoordinates.org/lightsquared-and-gps-2/feed/ 0 LightSquared and GPS http://mycoordinates.org/lightsquared-and-gps/ http://mycoordinates.org/lightsquared-and-gps/#comments Sun, 25 Sep 2011 07:47:30 +0000 admin http://mycoordinates.org/?p=11979 http://mycoordinates.org/lightsquared-and-gps/feed/ 0 Performance evaluation of the effect of QZS on precise positioning http://mycoordinates.org/performance-evaluation-of-the-effect-of-qzs-on-precise-positioning/ http://mycoordinates.org/performance-evaluation-of-the-effect-of-qzs-on-precise-positioning/#comments Fri, 22 Jul 2011 15:08:38 +0000 admin http://mycoordinates.org/?p=11625 A S (quasi-zenith satellite), which was anticipated to be the original Japanese positioning satellite, was launched in September, 2010. As an augmentation system of GNSS, two MTSATs had already been put into orbit and their main purpose is to broadcast the correction data for wide-area DGPS. This has actually improved the accuracy of wide area DGPS as a result of reception of the correction data from MSAS (MTSAT Satellite-based Augmentation System). The QZS also enhances the ranging function and it already has signal characteristics for the GNSS that are expected in the near future.]]> http://mycoordinates.org/performance-evaluation-of-the-effect-of-qzs-on-precise-positioning/feed/ 0 Road lane recognition using a precise digital map and GNSS http://mycoordinates.org/road-lane-recognition-using-a-precise-digital-map-and-gnss/ http://mycoordinates.org/road-lane-recognition-using-a-precise-digital-map-and-gnss/#comments Wed, 22 Jun 2011 16:00:48 +0000 admin http://mycoordinates.org/?p=11473 A precise digital map is needed to perform lane recognition using carrier-based GNSS position information.]]> http://mycoordinates.org/road-lane-recognition-using-a-precise-digital-map-and-gnss/feed/ 0 GNSS spoofing analysis by VIAS http://mycoordinates.org/gnss-spoofing-analysis-by-vias/ http://mycoordinates.org/gnss-spoofing-analysis-by-vias/#comments Sat, 22 Jan 2011 10:43:32 +0000 admin http://mycoordinates.org/?p=10171 A metric, Vulnerability Index Against Spoofing, is proposed and used to assess the effectiveness of a spoofer. The GNSS (Global Navigation Satellite System) positioning is known to be vulnerable to interference due to the long distance of radio-signal travel and the resulting low signal power. In the presence of interferences or spoofing, the GNSS navigation performance is likely to be degraded and the navigation function may even be incapacitated. Throughout the years, many GNSS interference mitigation techniques have been developed.]]> http://mycoordinates.org/gnss-spoofing-analysis-by-vias/feed/ 0 From Galileo to Multisystem: Evolution of Integrity concept http://mycoordinates.org/from-galileo-to-multisystem-evolution-of-integrity-concept/ http://mycoordinates.org/from-galileo-to-multisystem-evolution-of-integrity-concept/#comments Sat, 18 Dec 2010 12:31:33 +0000 admin http://mycoordinates.org/?p=9852 ,  The integrity concept, intended as a continuous control of the information broadcast by the satellites, has been introduced by the Galileo system. Though the RAIM technique represents the first example of integrity monitoring, it has the characteristic to detect only local errors, at receiver level. The integrity monitoring applied by EGNOS, instead, could be seen as the forerunner of the Galileo one. Though there are many differences in the definition of integrity of the two system, the main aim is the same for both, that is to protect the user...]]> http://mycoordinates.org/from-galileo-to-multisystem-evolution-of-integrity-concept/feed/ 0 More GPS or Smarter GPS? http://mycoordinates.org/more-gps-or-smarter-gps/ http://mycoordinates.org/more-gps-or-smarter-gps/#comments Mon, 20 Sep 2010 18:21:04 +0000 admin http://mycoordinates.org/?p=9029 James L Farrell, John W lavrakas Addressing GPS user problems While GPS offers a ubiquitous, precise, and reliable positioning and timing service to much of the world, in many cases this service falls short. Anyone who has walked into a building with a GPS receiver actively displaying a location is aware of the immediate effect of the ...]]> http://mycoordinates.org/more-gps-or-smarter-gps/feed/ 0 Phase centre determination on the basis of far-field measurements http://mycoordinates.org/phase-centre-determination-on-the-basis-of-far-field-measurements/ http://mycoordinates.org/phase-centre-determination-on-the-basis-of-far-field-measurements/#comments Tue, 17 Aug 2010 19:47:19 +0000 admin http://mycoordinates.org/?p=8828
, , ,
Phase centre is defined as a point (or a set of points) in space from which, when emitted, far-field phasefronts or, correspondingly, group-delay fronts are spherical or substantially spherical [1-2]. That is, the phase value is constant in a certain angular area of interest when measured with respect to the coordinate system whose origin is in the PC. However, PC is ambiguous for most of the real-life antennas and its position varies for...]]> http://mycoordinates.org/phase-centre-determination-on-the-basis-of-far-field-measurements/feed/ 0