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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.


Distribution of trajectories and gravity gradient (, unit: E).
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sensors-15-16833-f002: Distribution of trajectories and gravity gradient (, unit: E).

Mentions: Figure 2 shows the gradient of the down component of the gravity vector in down direction,, at an altitude of 3000 m in the test area with the flight trajectories. As the variations of the gravity gradient would have an effect on the navigation results, a total of 14 trajectories are generated for the tests. Out of these 14 trajectories, nine that fly from south to north are distributed with a 0.25° interval from longitude 127°. Among these nine trajectories, seven trajectories are from latitudes 35° to 38°, and the remaining two are from latitudes 35° to 37.5° to avoid the ocean area. Most trajectories show relatively small variations of the gravity gradients at the starting points, but large local variations occur as the flight passes mountainous areas. Out of the 14 trajectories, four are designed from west to east with latitudes from 127° to 129°; the latitudes of these trajectories are 35.5°, 36°, 36.5°, and 37°, respectively. The final of the 14 trajectories is generated to fly from southwest to northeast. Because the gravity gradient increases going toward the northeastern area, trajectory 14 experiences a huge variation in the gravity gradient from the second half of the flight duration.


Performance Evaluation and Requirements Assessment for Gravity Gradient Referenced Navigation.

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

Distribution of trajectories and gravity gradient (, unit: E).
© Copyright Policy
Related In: Results  -  Collection

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

sensors-15-16833-f002: Distribution of trajectories and gravity gradient (, unit: E).
Mentions: Figure 2 shows the gradient of the down component of the gravity vector in down direction,, at an altitude of 3000 m in the test area with the flight trajectories. As the variations of the gravity gradient would have an effect on the navigation results, a total of 14 trajectories are generated for the tests. Out of these 14 trajectories, nine that fly from south to north are distributed with a 0.25° interval from longitude 127°. Among these nine trajectories, seven trajectories are from latitudes 35° to 38°, and the remaining two are from latitudes 35° to 37.5° to avoid the ocean area. Most trajectories show relatively small variations of the gravity gradients at the starting points, but large local variations occur as the flight passes mountainous areas. Out of the 14 trajectories, four are designed from west to east with latitudes from 127° to 129°; the latitudes of these trajectories are 35.5°, 36°, 36.5°, and 37°, respectively. The final of the 14 trajectories is generated to fly from southwest to northeast. Because the gravity gradient increases going toward the northeastern area, trajectory 14 experiences a huge variation in the gravity gradient from the second half of the flight duration.

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.