TAG: pseudorange measurements

Innovation: Easy Peasy, Lemon Squeezy

October 1, 2012By
FIGURE 2. Illustration of the isolines of constant Doppler for one and two GNSS satellites. Sv and Uv are the satellite and receiver velocity vectors, respectively. ϴ is the angle between the velocity difference vector and the vector pointing from the satellite to the receiver. The figure on the right shows the intersection of Doppler ellipses for the two satellites.

Satellite Navigation Using Doppler and Partial Pseudorange Measurements
Have we outgrown the use of Doppler measurements for position fixing? It seems not. In this month’s column, we’ll take a look at a GNSS positioning technique that uses admittedly inaccurate Doppler-based position fixes as a first step in producing an accurate fix using just a snapshot of recorded Doppler frequency and code-phase data with no need to decode the navigation message. Old dog, new tricks. read more

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

Galileo’s Surveying Potential: E5 Pseudorange Precision

March 1, 2012By
Col-opener

New Galileo signals have great potential for pseudorange-based surveying and mapping in both optimal open-sky conditions and suboptimal under-canopy environments. This article reviews the main features of Galileo’s E5 AltBOC and E1 CBOC signals, describes generation of realistic E5 and E1 pseudoranges with and without multipath sources, and presents anticipated horizontal positioning accuracy results, ranging from 4 centimeters (open-sky) to 14 centimeters (under-canopy) for E5/E1. read more

This article is tagged with , , , , and posted in GNSS

Expert Advice: Cause Identified for Pseudorange Error from New GPS Satellite SVN-49

July 15, 2009By and

The GPS Wing and its contractors have traced the cause of pseudorange errors on L1 and L2 broadcast by the newest GPS satellite, SVN-49, to the manner in which the L5 signal demonstration payload was added to the satellite. Signal leakage between the two input ports of the antenna coupler network for the satellite's array of 12 helical antenna elements, reflected from the L5 filter and then transmitted, creates a second signal with a delay of approximately 30 nanoseconds, and the appearance of a multipath component. While testing an adjustment to the signal-in-space to minimize the effect of the problem on receiver navigation solutions on Earth, the GPS Wing is interested in hearing from manufacturers and the user community concerning the different impacts of SVN-49 signals on the wide range products and applications in operation, before reaching a final decision on what to do with the satellite prior to setting it healthy. read more