Innovation

Innovation: MBOC Signal Options

June 1, 2011By
Inno-opener

Performance of Multiplexed Binary Offset Carrier Modulations for Modernized GNSS Systems
A candidate for modernized GNSS civil signals in the L1/E1 band was BOC(1,1), a binary-offset-carrier signal with a "split spectrum" that has negligible impact on the existing GPS signals. However, a signal with better acquisition capabilities and improved multipath performance (while still compatible with the existing GPS signals) is a multiplexed BOC modulation, MBOC(6,1,1/11). The MBOC spectrum can be achieved by following one of several different signal-construction paths with some resulting differences in how a receiver tracks the signal and its associated performance. read more

This article is tagged with and posted in From the Magazine, GNSS, GPS Modernization, Innovation

Innovation: Doppler-Aided Positioning

May 1, 2011By
Figure 1. Satellite tracking and carrier-phase anomaly summary during the observation time-span. These data were collected in a dense urban environment in both static and kinematic mode. The superimposed red-points show epochs where carrier-phase observables are either missing or contaminated with cycle slips, loss of locks, and/or other measurement anomalies.

Improving Single-Frequency RTK in the Urban Enviornment
A look at how Doppler measurements can be used to smooth noisy code-based pseudoranges to improve the precision of autonomous positioning as well as to improve the availability of single-frequency real-time kinematic positioning, especially in urban environments. read more

This article is tagged with , and posted in Algorithms & Methods, From the Magazine, Innovation

Innovation: GLONASS

April 1, 2011By
Figure 8. SDCM website, www.sdcm.ru.(Click to enlarge.)

Developing Strategies for the Future
A team of authors from Russian Space Systems, a key developer of navigation and geospatial technologies in the Russian aerospace industry, describes the new L3 CDMA signal to be broadcast by GLONASS-K satellites and the progress to date in developing the SDCM augmentation system. read more

This article is tagged with and posted in From the Magazine, GLONASS, Innovation

Innovation: Realistic Randomization

March 1, 2011By
Figure 3. Data collection, Gamla Stan (Old Town), Stockholm (route and street view).

New Way to Test GNSS Receivers
In this month’s article, we look at an approach to GNSS receiver testing that uses realistic randomization of signal amplitudes based on histograms of carrier-to-noise-density ratios observed in real-world environments. It can be applied to any simulator scenario, independent of scenario details (position, date, time, motion trajectory, and so on), making it possible to control relevant parameters such as the number of satellites in view and the resulting dilution of precision independent of signal-strength distribution. The method is amenable to standardization and could help the industry to improve the testing methodology for positioning devices — to one that is more meaningfully related to real-world performance and user experience. read more

This article is tagged with , , and posted in GNSS, Innovation, Signal Processing

Innovation: GNSS and the Ionosphere

February 1, 2011By
Figure 4. Photo of red and green auroras observed near Fredericton, New Brunswick, Canada (46 degrees north latitude) early on October 31, 2003. (Courtesy of Richard and Marg Langley.)

What’s in Store for the Next Solar Maximum?
Although the sun can become disturbed at any time, solar activity is correlated with the approximately 11-year cycle of spots on the sun’s surface. We are just coming out of a minimum in the solar cycle and headed for the next maximum, predicted to occur around the middle of 2013. How significantly will GNSS users be affected? In this month’s column, two ionosphere experts tell us what might be in store. read more

This article is tagged with and posted in From the Magazine, Innovation, Signal Processing

Innovation: The Distress Alerting Satellite System

January 1, 2011By
Cospas–Sarsat system.

Taking the Search out of Search and Rescue
In 1997, a Canadian government study determined that an improved search and rescue system would be one based on medium-Earth orbit satellites, which can provide full global coverage, can determine beacon location, and would need fewer ground stations. This month’s column examines the architecture of the GPS-based Distress Alerting Satellite System and takes a look at early test results. read more

Innovation: Record, Replay, Rewind

October 1, 2010By
opener-copy

Testing GNSS Receivers with Record and Playback Techniques
Is there a way to perform repeatable tests on GNSS receivers using real signals? This month’s column looks at how to use an RF vector signal analyzer to digitize and record live signals, and then play them back to a GNSS receiver with an RF vector signal generator. read more

This article is tagged with , and posted in From the Magazine, Innovation, Signal Processing

Innovation: Friendly Reflections

September 1, 2010By
Figure 4. The Oceanpal installation at Lake Laja, Chile.

Monitoring Water Level with GNSS
A receiver can selectively acquire scattered signals and the resulting measurements can be interpreted to reveal certain characteristics of the source of the scattering. This article discusses the design and application of a GNSS instrument that uses scattered signals for monitoring the level and roughness of inland and coastal water surfaces for the betterment of planet Earth. read more

This article is tagged with and posted in From the Magazine, Innovation, Remote Sensing