Use of comb filters in GPS L1 receivers

Use of Comb Filters in GPS L1 Receivers

Comb filters can be designed by replacing single delays in digital filters by multiple delays. These filters are " periodic " in the sense that their frequency response repeats itself at fixed intervals. They are thus well suited to a signal such as GPS L1 which has a spectrum made up of lines separated by the code repetition frequency of 1 kHz. In this paper we examine how periodic filters can...

How Comb Filters can be used in GNSS Receivers

This is a non-refereed presentation that examines the use of comb filters in GNSS receivers, reviewing some of the discussion recently presented in [1]. Because the GPS L1 C/A code signal has a spectrum made up of lines regularly spaced at 1kHz intervals, the use of comb filters, which have regularly spaced passor stop-bands, would on the face of it seem a logical step. It is shown, however, th...

Infrared Filters for Cryogenic Receivers

Evaluation of High Sensitivity GPS Receivers

GPS is the popular positioning technology widely used for many applications. However, many GPS receivers have difficulty tracking signals in harsh environments such as urban canyons or indoors. So-called “high sensitivity” GPS (HSGPS) receivers have been developed to address this problem, and nowadays many different models of HSGPS receivers can be found in the market. For example, the latest m...

A Novel Interference Rejection Method for GPS Receivers

This paper proposes a new method for rejecting the Continuous Wave Interferences (CWI) in the Global Positioning System (GPS) receivers. The proposed filter is made by cascading an adaptive Finite Impulse Response (FIR) filter and a Wavelet Packet Transform (WPT) based filter. Although adaptive FIR filters are easy to implement and have a linear phase, they create self-noise in the rejection of...