GPS Receiver Testing

By National Instruments

Overview

From the airplane pilot operating a Boeing 747, to the everyday consumer using a GPS navigation system in his car, to the hobbyist searching for buried treasure in the forest, GPS technology is quickly becoming integrated in a wide variety of applications. As innovation drives GPS receivers to even better performance, techniques used to characterize performance are becoming increasingly sophisticated as well. Today, with the power of software, you can create GPS waveforms that accurately emulate the real-world signal. In addition, advances in instrument bus technology enable record and playback of live GPS signals with PXI instrumentation.

Introduction

As GPS technology becomes more commonplace on the commercial market, many designers are working to improve characteristics such as lower power consumption, the tracking of weak satellites, faster acquisition times, and more accurate position fixes. In this application note, learn how to make a variety of GPS receiver measurements including sensitivity, noise figure, position accuracy, time to first fix (TTFF), and position deviation. The goal of this document is to provide engineers with a thorough understanding of GPS measurement techniques. For engineers who are new to GPS receiver measurements, this paper offers a comprehensive overview of common measurements. Engineers who are already experienced at performing GPS measurements can use this document as a resource to introduce new instrumentation technology.