Dilution of Precision (DOP) is one of the most fundamental quality indicators for GNSS users. Even though there are some limitations such as described here. DOP can be very important for planning GNSS surveys as well as performing quality control or…

  • Dilution of precision , GNSS , Simulation

Last week the sun sent a mass of charged particles tumbling towards Earth. According to the Space Weather Prediction Center's analysis, the most significant activity occured Friday September 12th, 2014 as shown in thier Kp Index Plot which reached a…

  • PPP , solar storms , ionosphere

A geomagnetic storm warning has been issused due to a coronal mass ejection (CME) occuring on September 10, 2014. The brunt of the the effects are expected to arrive at the earth's atmosphere on Saturday September 13, 2014. While many media outlets l…

  • GNSS , Solar Storms , Ionosphere , Space Weather

In Part 1 and Part 2 we discussed how to use RTKLib for standard point positioning and baseline processing. In Part 3 we look at how to use RTKLib to perform Precise Point Positioning (PPP) with orbit and clock products from the IGS. Unlike tradition…

  • RTKLib , GPS , PPP

In order to determine a user's position, a GPS receiver must know the position of the satellites transmitting the ranging signals to the user. Included in the ranging signal received by GPS receivers is a navigation message that includes, among other…

  • GPS , Ephemeris , Leap Seconds

Previously we discussed the benefits of using DOP as a planning tool. However, DOP has its limitations. While a poor DOP will generally mean poor accuracy, a good DOP may not mean good accuracy. With older receivers, as well as high accuracy rece…

  • dilution of precision , GIS