TAG: algorithms and methods

Innovation: Galileo cycle-slip detection

September 1, 2016By and
FIGURE 3.  Statistical and absolute thresholds.

How four frequencies help when the ionosphere is disturbed
The authors explore how cycle slips in Galileo carrier-phase measurements can be more effectively detected using four frequencies. read more

ComNav releases Quantum algorithm for its OEM boards

July 26, 2016By
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ComNav Technologies has released its new generation Quantum algorithm to international market. The Quantum algorithm can be easily achieved through a firmware upgrade (version 2.5.2 and above), and suits all ComNav OEM boards and OEM-based receivers. An upgrade to ComNav’s Quan algorithm, the Quantum algorithm dramatically improves  the stability and reliability of RTK positioning in complex environments, as well as providing a DP-filter enhancement... read more

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Innovation: Getting There by Tuning In

September 4, 2015By
FIGURE 8. Worst-case result for five-transmitter tracking. (Photo map courtesy of Google.)

Using HD Radio Signals for Navigation By Ananta Vidyarthi, H. Howard Fan and Stewart DeVilbiss THE YEAR WAS 1906. On Christmas Eve of that year, Canadian inventor Reginald Fessenden carried out the first amplitude modulation (AM) radio broadcast of voice and music. He used a high-speed alternator capable of rotating at up to 20,000 revolutions per minute (rpm). Connected to... read more

Sentry Stands on Jammer Alert

July 31, 2015By
FIGURE 4. Urban area test; jammer locations
in yellow, locations delivered by Signal
Sentry in red, sensor locations in green.

By Jeffrey Coffed and Joseph Rolli, Harris The first and best step to combat the growing worldwide problem of GPS jamming is to pursue technologies that can detect and locate the jammers. Signal Sentry 1000 uses arrayed sensors to do just that: look out for jamming and track down its source once sensed. An array of sensors can be deployed... read more

Innovation: Carrier-Phase RF Ranging

June 8, 2015By
FIGURE 10. Histogram showing carrier-phase range accuracy.

Precise, Accurate and Multipath-Resistant Distance and Speed Measurements
In this month’s column, we take a look at a short-distance two-way ranging system using a 5.8-GHz carrier to supply not only precise and accurate distance measurements but also complementary measurements of speed. read more

Innovation: Carrier-Phase Ambiguity Resolution

April 3, 2015By
FIGURE 9. Network used for the triple-frequency PPP study.

Handling the Biases for Improved Triple-Frequency PPP Convergence
Precise point positioning (PPP) can be considered a viable tool in the kitbag of GPS positioning techniques. One precision aspect of PPP is its use of carrier-phase measurements rather than just pseudoranges. But there is a catch. Often many epochs of measurements are needed for a position solution to converge to a sufficiently high accuracy. In this month’s column, we look at how using measurements from three satellite frequencies rather than just two can help. read more

Galileo E1, E5a Performance for Multi-Frequency, Multi-Constellation GBAS

April 1, 2015By
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Analysis of new Galileo signals at an GBAS compares noise and multipath in their performance to GPS L1 and L5. Even after smoothing, Galileo signals perform somewhat better than GPS and are less sensitive to the smoothing time constant. read more

Innovation: Where Are We?

March 5, 2015By
FIGURE 4. Trajectory solutions.

Positioning in Challenging Environments Using Ultra-Wideband Sensor Networks
The use of large transmission bandwidths offers a number of benefits, including accurate ranging and that application in particular is being actively developed for positioning and navigation in environments that are challenging to GNSS such as indoors and built-up areas. In this month’s column, we take a look at the work being carried out in this area by a team of researchers at The Ohio State University. read more