GPS News


Sep 2011 | No Comment


50th Space Wing gains control of newest GPS Satellite

The 50th Space Wing’s 2nd Space Operations Squadron accepted command and control of the second Global Positioning System Block IIF satellite. The Space and Missile Systems Center’s GPS Directorate, located at Los Angeles Air Force Base, remained in control of the satellite during a 30-day on-orbit checkout period before the hand-off to 2 SOPS. The next-generation GPS IIF satellites built by Boeing will provide improved accuracy through advanced atomic clocks, a longer design life than legacy GPS satellites, and a new third civil signal, L5 that will eventually benefit commercial aviation and safety-of-life applications

Air Force to replace ailing GPS satellite with a spare already in orbit

A failing Global Positioning System satellite is being replaced with a spare satellite currently in orbit. The Air Force said that the satellite’s clock began malfunctioning in May. The backup satellite was switched on in June and functioned well. The Air Force says it will be tested over the next week before it is returned to active status. The backup satellite was decommissioned in 2009 to make room for a newer model.

ProconGPS, Inc. files suit Against Sky Patrol, Star Sensor and Others for patent infringement

ProconGPS has filed a patent infringement lawsuit in a California Federal Court against Star Sensor, Skypatrol LLC and others. The complaint is related to U.S. patents 6,249,217 B1 & 6,025,774 and involves an innovative system that applies GPStechnology, cellular networks, and information systems to monitor loan status for a default condition on a vehicle and to enable tracking to aid the confiscation and repossession process for dealers and finance companies. Early estimates are the damages caused by infringing companies could exceed $10,000,000. ProconGPS Inc. will also seek injunctive relief to prevent infringers from providing unlicensed products and services.

Loss of space freighter delays Glonass-M launch

The launch of Glonass-M navigation satellite has been postponed for an additional equipment check, announced Russia’s Space Forces commander, Gen. Oleg Ostapenko. He said, “Presumably, satellite will be launched in early September.” The launch of the satellite was scheduled for August 26, 2011 from the Plesetsk Space Center in northern Russia by Soyuz-2.1B carrier rocket. The announcement came shortly after Russia lost its second spacecraft in less than a week and Russian Prime Minister Vladimir Putin ordered thorough quality control checks of all aerospace equipment.

Recently, Progress M-12M space freighter fell in South Siberia’s Altai Republic after failing to separate from its Soyuz-U carrier rocket, the first loss of a Progress freighter in the history of Russia’s space industry. The third stage rocket engine was blamed for the spacecraft loss. This launch failure follows an unsuccessful attempt to orbit the Express AM-4 telecommunications satellite, which failed to separate from the Proton-M carrier rocket on August 18, 2011, and could not reach the designated location.

The spacecraft loss, however, will not affect the first Soyuz-ST launch from the Kourou Space Center in French Guiana scheduled for this October, Arianespace CEO Jean-Yves Le Gall said.

“In principle, the launch date of October 20 is confirmed, because the Soyuz being used for Galileo is not impacted by yesterday’s failure,” Le Gall added. “The problem that occurred yesterday is linked to a third-stage motor, and the Soyuz model that we will be using uses a different third stage.”

RIA Novosti

Toucans wearing GPS backpacks help Smithsonian scientists study seed dispersal

Nutmeg-loving toucans wearing GPS transmitters recently helped a team of scientists at the Smithsonian Tropical Research Institute in Panama address an age-old problem in plant ecology: accurately estimating seed dispersal. The tracking data revealed what scientists have long suspected, that toucans are excellent seed dispersers, particularly in the morning, and for the first time enabled researchers to create a map of the relative patterns and distances that toucans distribute the seeds of a nutmeg tree.

The reproductive success of any fruiting plant depends upon how effectively its seeds are dispersed yet tracking and mapping individual seeds carried off by the wind or ingested by animals is nearly impossible. Today, ecologists studying forest dynamics rely mostly on theoretical models to calculate the area of seed distribution for specific plants. New tracking technology however is changing that.

China to launch civil survey satellite, ZY 3

China will put into space a high-definition civil survey satellite, the first of its kind in the country, at the end of this year, announced Song Chaozhi, Deputy Director of the National Administration of Surveying, Mapping and Geoinformation. The satellite, ZY 3, will be launched from the Taiyuan Satellite Launch Center in north Shanxi Province. Once successfully launched, the satellite will operate in a sun-synchronous orbit at about 506 kilometres in altitude and be capable of producing seamless imagery of the earth’s surface from 84 degrees south latitude to 84 degrees north latitude, according to a statement issued from the Administration.

The satellite will help the mapping efforts in the country’s western regions where geographic information is difficult to collect and update due to limits of equipment and technology, Song said. In addition, the administration announced that China has finished the surveying and mapping for the first 1:50,000 scale map in the country’s western regions of about 2 million square kilometres.
The map will provide geographic information for the country’s water conservancy, transportation, energy and telecommunication projects, the administration said in a statement.


Software improves accuracy of GPS

Researchers at the Ohio State University in the US developed a software to fix GPS errors. According to the initial test, the software enabled centimetre-scale GPS positioning – including altitude – as often as 97 percent of the time. Researchers claimed the software will help to improve the vertical accuracy of measurements in potentially hazardous regions at high altitudes, such as areas of soft, loose land that may be prone to landslides. They also claim that their software could be used to measure how quickly glaciers at high altitudes are melting.

GPS satellites transmit information in the form of radio waves to the GPS receiver held by the user. At the same time, the signals must also travel to at least one other ground-based receiver to obtain a location reference, which allows the user’s receiver in turn to accurately calculate its own position in 3D. Before the satellite signals reach the receivers, they must travel through Earth’s atmosphere, which results in time delays that affect accuracy.

When the user’s receiver and the reference receiver reside at drastically different altitudes, however, each location experiences different amounts of time delay, which complicates matters even further. So, in mountainous regions where height differences can vary greatly over a short distance, acquiring the altitude of locations to within a few centimetres is difficult.

“Time is the heart that drives GPS, so it is important that we have a proficient method that accounts for delays from earth’s atmospheric layers,” said Grejner-Brzezinska, one of the researchers. “It would be ideal for all GPS signals to travel in a straight line directly to their destination, but due to electron interaction and refraction in the lower atmosphere, the signal’s path is far from straight,” she continued.

Electron interaction and tropospheric refraction effectively re-route the GPS signal, which means that the signal travels an extra distance and requires extra time, said Grejner-Brzezinska.

She and her colleagues looked specifically at troposphere delays – those caused by the lowest level of the atmosphere. Their study can be found in a recent issue of the journal Measurement Science and Technology.

This research was funded by the European Space Agency Plan for European Cooperating States project and a grant from the Polish Ministry of Science and Higher Education.

Ohio State University

LINZ broadcasts real-time GNSS data

Land Information New Zealand (LINZ) started publicly broadcasting real-time Global Navigation Satellite System (GNSS) data. The data is streamed free-of-charge from 39 Continuously Operating Reference Stations (CORS) throughout the country. This includes 34 LINZ PositioNZ stations and 5 stations which are part of the GeoNet project run by GNS Science. Users can connect to a data stream in the field using their GNSS receiver and a cellular connection. This enables Real-Time Kinematic (RTK) positioning to be carried out, without the need to set up a separate base station.

To help monitor the reliability of the network, LINZ has established an online monitoring tool on the PositioNZ-RT webpage. PositioNZ is LINZ’s Global Positioning System Active Control Network.


Interference to GPS from LightSquared network

The Final Report of the Technical Working Group mandated by the Federal Communications Commission and conducted jointly by LightSquared and the GPS community of manufacturers and users has been filed with the FCC. It shows that LightSquared’s proposed network would cause devastating interference to all kinds of GPS receivers tested including those used in Aviation, Cellular phones, General Location and Navigation (including Automotive, Public Safety, Personal and Marine Navigation), High Precision and Networks (including Agriculture, Surveying, Construction and Monitoring of Dams, Structures, Earthquakes and Volcanoes), and GPS Timing. The results show that the network would also jam LightSquared’s own satellite transmissions and those of others in the same Mobile Satellite Services (MSS) band, being used in many important land and marine based industrial and safety applications.

Schlesinger, Parkinson Address FCC: Rescind LightSquared Waiver

The two co-chairs of the U.S. National Advisory Board for Space-Based Positioning, Navigation, and Timing, the Hon James R Schlesinger and Dr Bradford Parkinson, have delivered an official, strongly worded letter today to Julius Genachowski, chairman, Federal Communications Commission. The letter “formally requests that the Federal Communications Commission rescind the conditional waiver approving LightSquared terrestrial operations in the MSS radio band from 1525-1559 MHz, and instead select an appropriate band that would avoid the substantial collateral damage in its understandable quest to bring broadband to the American public.”

The two writers add that “The proposal would radically change a primary space-to-earth radio band to allow high-power terrestrial broadcasts. As shown by comprehensive industry and government testing and analyses, if this proposal were allowed to proceed, it would have the unavoidable consequence of adversely impacting current and planned Federal and private sector infrastructure. The costs would be tens of billions of dollars per year. Such a loss would impact our nation’s national security, international standing and have a notable economic impact. It is not an acceptable alternative to impose this burden on behalf of a single company.”

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