Innovation: Faster, Higher, Stronger

October 8, 2015By
FIGURE 2. Typical sequence of position fix process in standalone GPS user equipment (Msr=measurements).

Proposed GNSS Navigation Messages for Improved Performance
In this month’s column, we look at proposed changes to the way navigation messages are formulated that could result in a future satellite navigation system providing faster fixes effectively giving receivers higher sensitivity and stronger performance. read more

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

Innovation: Seeing the Light

July 1, 2015By
FIGURE 2. GRD-based image correspondence illustration as a function of 2-D relative navigation state.

We look at the development of a generalized vision-aided integrity monitor for precision relative navigation applications. A vision-aided integrity monitor could be extremely valuable in augmenting existing precision relative navigation systems, such as GPS, for many different safety-critical aerospace applications. 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: Robustness to Faults for a UAV

May 4, 2015By
FIGURE 3. Goldy flight control system.

Integrated Navigation Systems Using Parallel Filtering
The authors look at the development of a robust navigation system employing a GNSS receiver, accelerometers, gyroscopes, magnetometers, an airspeed device and dead reckoning to supply a blended navigation solution to a flight control system on a small, unmanned aerial vehicle. 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

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

Innovation: Python GNSS Receiver

February 1, 2015By
FIGURE 8. The trip back to Puno as determined by Receiver Y after cooperative scalar tracking and navigation computations. Compared to Figure 4, the navigation solutions are less noisy. Image courtesy of Google Earth and the GPS Visualizer.

An Object-Oriented Software Platform Suitable for Multiple Receivers
An experiment highlights the abilities of the Python Receiver, showing how it has been used to develop a software-defined GNSS receiver — one well-suited to processing data from a network of receiver front ends. read more