Performance Improvement of Code-Carrier DGPS with a Scalar Adaptive Filter

Abstract

This paper presents the code-carrier DGPS method providing a stable navigation solution under the condition of frequent blockage of the GPS signals. Hatch filter combines code measurements and carrier phase measurements, so the accuracy of filter depends on both measurements. If the tests are conducted under the urbancanyon environment where the cycle slip is frequent, the averaged code accuracy cannot reach the low noise level. The proposed algorithm uses a scalar adaptive filter as a pre-filter of Hatch filter and then calculated the more accurate solution. Simulation shows that the presented result is as good as commercial system with real data.