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NLOS Correction/Exclusion for GNSS Measurement Using RAIM and City Building Models.

Hsu LT, Gu Y, Kamijo S - Sensors (Basel) (2015)

Bottom Line: The proposed RAIM fault detection and exclusion (FDE) is able to compare the similarity between the raw pseudorange measurement and the simulated pseudorange.Because of the assumption of the single reflection in the ray-tracing technique, an inconsistent case indicates it is a double or multiple reflected NLOS signal.According to the experimental results, the RAIM satellite selection technique can reduce by about 8.4% and 36.2% the positioning solutions with large errors (solutions estimated on the wrong side of the road) for the 3D building model method in the middle and deep urban canyon environment, respectively.

View Article: PubMed Central - PubMed

Affiliation: Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan. qmohsu@kmj.iis.u-tokyo.ac.jp.

ABSTRACT
Currently, global navigation satellite system (GNSS) receivers can provide accurate and reliable positioning service in open-field areas. However, their performance in the downtown areas of cities is still affected by the multipath and none-line-of-sight (NLOS) receptions. This paper proposes a new positioning method using 3D building models and the receiver autonomous integrity monitoring (RAIM) satellite selection method to achieve satisfactory positioning performance in urban area. The 3D building model uses a ray-tracing technique to simulate the line-of-sight (LOS) and NLOS signal travel distance, which is well-known as pseudorange, between the satellite and receiver. The proposed RAIM fault detection and exclusion (FDE) is able to compare the similarity between the raw pseudorange measurement and the simulated pseudorange. The measurement of the satellite will be excluded if the simulated and raw pseudoranges are inconsistent. Because of the assumption of the single reflection in the ray-tracing technique, an inconsistent case indicates it is a double or multiple reflected NLOS signal. According to the experimental results, the RAIM satellite selection technique can reduce by about 8.4% and 36.2% the positioning solutions with large errors (solutions estimated on the wrong side of the road) for the 3D building model method in the middle and deep urban canyon environment, respectively.

No MeSH data available.


Weighting of all the particles of point 264,308 before (a) and after RAIM (b).
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sensors-15-17329-f010: Weighting of all the particles of point 264,308 before (a) and after RAIM (b).

Mentions: As a result, the pseudorange difference between the simulated and raw pseudorange is large. This large difference results in the particle on the left side of the street in Figure 8a to become invalid. With the aid of the proposed RAIM, GPS 11 is excluded from the particles of Figure 8b. This exclusion facilitates the proposed 3D map method to estimate the correct side of the street in this case. With regard to point 264,038, the positioning results before and after applying RAIM are similar, as shown in the right side of Figure 7. Figure 10 shows the weighting of all the particles in this point. The GLONASS satellites 5 and 20 are both single reflected NLOS, as indicated by the pseudorange measurements, which are similar to their simulated pseudorange, as shown in Figure 11b. In this case, both the GLONASS NLOS satellites’ measurements are safe to use. Thus, the position estimated by the 3D map method standalone is close to the ground truth.


NLOS Correction/Exclusion for GNSS Measurement Using RAIM and City Building Models.

Hsu LT, Gu Y, Kamijo S - Sensors (Basel) (2015)

Weighting of all the particles of point 264,308 before (a) and after RAIM (b).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541937&req=5

sensors-15-17329-f010: Weighting of all the particles of point 264,308 before (a) and after RAIM (b).
Mentions: As a result, the pseudorange difference between the simulated and raw pseudorange is large. This large difference results in the particle on the left side of the street in Figure 8a to become invalid. With the aid of the proposed RAIM, GPS 11 is excluded from the particles of Figure 8b. This exclusion facilitates the proposed 3D map method to estimate the correct side of the street in this case. With regard to point 264,038, the positioning results before and after applying RAIM are similar, as shown in the right side of Figure 7. Figure 10 shows the weighting of all the particles in this point. The GLONASS satellites 5 and 20 are both single reflected NLOS, as indicated by the pseudorange measurements, which are similar to their simulated pseudorange, as shown in Figure 11b. In this case, both the GLONASS NLOS satellites’ measurements are safe to use. Thus, the position estimated by the 3D map method standalone is close to the ground truth.

Bottom Line: The proposed RAIM fault detection and exclusion (FDE) is able to compare the similarity between the raw pseudorange measurement and the simulated pseudorange.Because of the assumption of the single reflection in the ray-tracing technique, an inconsistent case indicates it is a double or multiple reflected NLOS signal.According to the experimental results, the RAIM satellite selection technique can reduce by about 8.4% and 36.2% the positioning solutions with large errors (solutions estimated on the wrong side of the road) for the 3D building model method in the middle and deep urban canyon environment, respectively.

View Article: PubMed Central - PubMed

Affiliation: Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan. qmohsu@kmj.iis.u-tokyo.ac.jp.

ABSTRACT
Currently, global navigation satellite system (GNSS) receivers can provide accurate and reliable positioning service in open-field areas. However, their performance in the downtown areas of cities is still affected by the multipath and none-line-of-sight (NLOS) receptions. This paper proposes a new positioning method using 3D building models and the receiver autonomous integrity monitoring (RAIM) satellite selection method to achieve satisfactory positioning performance in urban area. The 3D building model uses a ray-tracing technique to simulate the line-of-sight (LOS) and NLOS signal travel distance, which is well-known as pseudorange, between the satellite and receiver. The proposed RAIM fault detection and exclusion (FDE) is able to compare the similarity between the raw pseudorange measurement and the simulated pseudorange. The measurement of the satellite will be excluded if the simulated and raw pseudoranges are inconsistent. Because of the assumption of the single reflection in the ray-tracing technique, an inconsistent case indicates it is a double or multiple reflected NLOS signal. According to the experimental results, the RAIM satellite selection technique can reduce by about 8.4% and 36.2% the positioning solutions with large errors (solutions estimated on the wrong side of the road) for the 3D building model method in the middle and deep urban canyon environment, respectively.

No MeSH data available.