In single frequency (Ll) GPS receivers, multipath is the dominant error source in differential ca... more In single frequency (Ll) GPS receivers, multipath is the dominant error source in differential carrier phase and pseudorange measurements. Consequently, it is the dominant error effecting DGPS positioning accuracy. The Multipath Estimating Delay Lock Loop (MEDLL) is a method for mitigating the effects due to multipath within the receiver tracking loops. The MEDLL does this by separating the incoming signal into its line-ofsight and multipath components. Using the line-of-sight component, the unbiased measurements of code and carrier phase can be made. In previous papers, the authors have demonstrated MEDLL performance in mitigating the effects of multipath on C/A code pseudorange measurements, Also, they have shown that it is possible to use the MEDLL derived parameters to calculate a multipath error correction for the carrier phase measurements. This carrier phase multipath correction has now been implemented in NovAtel’s MEDLL receiver. Using a GPS signal simulator, the carrier ph...
This paper starts with a brief overview of radio channel models. The most important parameter in ... more This paper starts with a brief overview of radio channel models. The most important parameter in these models is the delay spread, since this is directly related to the complexity of a modem. Various measurement results reported in the literature are summarized, showing that for most office buildings, the delay spread is the range of 40 to 70 ns, while larger delay spreads up to 300 ns can be expected in large buildings like shopping centers and factories.
In single frequency (Ll) GPS receivers, multipath is the dominant error source in differential ca... more In single frequency (Ll) GPS receivers, multipath is the dominant error source in differential carrier phase and pseudorange measurements. Consequently, it is the dominant error effecting DGPS positioning accuracy. The Multipath Estimating Delay Lock Loop (MEDLL) is a method for mitigating the effects due to multipath within the receiver tracking loops. The MEDLL does this by separating the incoming signal into its line-ofsight and multipath components. Using the line-of-sight component, the unbiased measurements of code and carrier phase can be made. In previous papers, the authors have demonstrated MEDLL performance in mitigating the effects of multipath on C/A code pseudorange measurements, Also, they have shown that it is possible to use the MEDLL derived parameters to calculate a multipath error correction for the carrier phase measurements. This carrier phase multipath correction has now been implemented in NovAtel’s MEDLL receiver. Using a GPS signal simulator, the carrier ph...
This paper starts with a brief overview of radio channel models. The most important parameter in ... more This paper starts with a brief overview of radio channel models. The most important parameter in these models is the delay spread, since this is directly related to the complexity of a modem. Various measurement results reported in the literature are summarized, showing that for most office buildings, the delay spread is the range of 40 to 70 ns, while larger delay spreads up to 300 ns can be expected in large buildings like shopping centers and factories.
Uploads