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Performance Evaluation and Requirements Assessment for Gravity Gradient Referenced Navigation.

Lee J, Kwon JH, Yu M - Sensors (Basel) (2015)

Bottom Line: It is found that DB and sensor errors and flight altitude have strong effects on the navigation performance.Considering that the accuracy of currently available gradiometers is about 3 E or 5 E, GGRN does not show much advantage over TRN at present.However, GGRN is expected to exhibit much better performance in the near future when accurate DBs and gravity gradiometer are available.

View Article: PubMed Central - PubMed

Affiliation: Department of Geoinformatics, University of Seoul, Seoul 130-743, Korea. leejs@uos.ac.kr.

ABSTRACT
In this study, simulation tests for gravity gradient referenced navigation (GGRN) are conducted to verify the effects of various factors such as database (DB) and sensor errors, flight altitude, DB resolution, initial errors, and measurement update rates on the navigation performance. Based on the simulation results, requirements for GGRN are established for position determination with certain target accuracies. It is found that DB and sensor errors and flight altitude have strong effects on the navigation performance. In particular, a DB and sensor with accuracies of 0.1 E and 0.01 E, respectively, are required to determine the position more accurately than or at a level similar to the navigation performance of terrain referenced navigation (TRN). In most cases, the horizontal position error of GGRN is less than 100 m. However, the navigation performance of GGRN is similar to or worse than that of a pure inertial navigation system when the DB and sensor errors are 3 E or 5 E each and the flight altitude is 3000 m. Considering that the accuracy of currently available gradiometers is about 3 E or 5 E, GGRN does not show much advantage over TRN at present. However, GGRN is expected to exhibit much better performance in the near future when accurate DBs and gravity gradiometer are available.

No MeSH data available.


Horizontal error as a function of DB resolution in trajectory No. 9.
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sensors-15-16833-f003: Horizontal error as a function of DB resolution in trajectory No. 9.

Mentions: In general, better navigation results are expected when the DB resolution is higher. However, navigation performance in the case of using low-resolution DBs is sometimes better when the data changes abruptly. Figure 3 shows the horizontal position error of trajectory No. 9. In this figure, the red and blue lines indicate the horizontal errors corresponding to the application of 30 arcsec and 60 arcsec DBs, respectively. As shown in the figure, the positions of the vehicle are determined more precisely with a higher-resolution DB for a majority of the navigation time. However, the horizontal error for the 60-arcsec-resolution DB is smaller in the time window between 1000 s and 1300 s. This kind of event is commonly observed in situations where the linearity between the measurements and the states is broken. In other words, the true aircraft position and the INS-indicated position could be located on the same slope in a lower-resolution DB but they could be located on opposite slopes in a higher-resolution DB. Therefore, it would be a better to use a low-resolution DB in the abruptly changing region to obtain stable navigation results.


Performance Evaluation and Requirements Assessment for Gravity Gradient Referenced Navigation.

Lee J, Kwon JH, Yu M - Sensors (Basel) (2015)

Horizontal error as a function of DB resolution in trajectory No. 9.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541910&req=5

sensors-15-16833-f003: Horizontal error as a function of DB resolution in trajectory No. 9.
Mentions: In general, better navigation results are expected when the DB resolution is higher. However, navigation performance in the case of using low-resolution DBs is sometimes better when the data changes abruptly. Figure 3 shows the horizontal position error of trajectory No. 9. In this figure, the red and blue lines indicate the horizontal errors corresponding to the application of 30 arcsec and 60 arcsec DBs, respectively. As shown in the figure, the positions of the vehicle are determined more precisely with a higher-resolution DB for a majority of the navigation time. However, the horizontal error for the 60-arcsec-resolution DB is smaller in the time window between 1000 s and 1300 s. This kind of event is commonly observed in situations where the linearity between the measurements and the states is broken. In other words, the true aircraft position and the INS-indicated position could be located on the same slope in a lower-resolution DB but they could be located on opposite slopes in a higher-resolution DB. Therefore, it would be a better to use a low-resolution DB in the abruptly changing region to obtain stable navigation results.

Bottom Line: It is found that DB and sensor errors and flight altitude have strong effects on the navigation performance.Considering that the accuracy of currently available gradiometers is about 3 E or 5 E, GGRN does not show much advantage over TRN at present.However, GGRN is expected to exhibit much better performance in the near future when accurate DBs and gravity gradiometer are available.

View Article: PubMed Central - PubMed

Affiliation: Department of Geoinformatics, University of Seoul, Seoul 130-743, Korea. leejs@uos.ac.kr.

ABSTRACT
In this study, simulation tests for gravity gradient referenced navigation (GGRN) are conducted to verify the effects of various factors such as database (DB) and sensor errors, flight altitude, DB resolution, initial errors, and measurement update rates on the navigation performance. Based on the simulation results, requirements for GGRN are established for position determination with certain target accuracies. It is found that DB and sensor errors and flight altitude have strong effects on the navigation performance. In particular, a DB and sensor with accuracies of 0.1 E and 0.01 E, respectively, are required to determine the position more accurately than or at a level similar to the navigation performance of terrain referenced navigation (TRN). In most cases, the horizontal position error of GGRN is less than 100 m. However, the navigation performance of GGRN is similar to or worse than that of a pure inertial navigation system when the DB and sensor errors are 3 E or 5 E each and the flight altitude is 3000 m. Considering that the accuracy of currently available gradiometers is about 3 E or 5 E, GGRN does not show much advantage over TRN at present. However, GGRN is expected to exhibit much better performance in the near future when accurate DBs and gravity gradiometer are available.

No MeSH data available.