- What did you personally accomplish this week on the project?
Last week, I worked on optimizing localization algorithm and distance measuring methods to reduce the lagging.
First of all, we used SGD to estimate the current position before. However, the computation time of running SGD is too long such that it will create lagging when we are walking around. The case is even worse when we try to run our algorithm on Raspberry Pi. Thus, I worked on changing our algorithm from using SGD to merely Numpy such that it doesn’t has as much computation stress as SGD.
Second, I did research on distance measuring methods. TWR vs. TDOA. Before, we were using TWR to measure the distances. Although TWR is more accurate when it gets closer to the range(about 25 meters in our case), it needs time to transmitt 9 messages each time, which requires some time to actually get the measurement. For TDOA, it only needs 1 message to get the distance, which requires less time. The distances may get less accurate when it gets closer to the range, but since we are using a lot of anchors, it can reduce the effect of inaccuracy because the distances between the tag and closer anchors are more accurate.
Github Repo: https://github.com/weelieguo/18500-dw1001
- Is your progress on schedule or behind?
Based on the schedule, I should still working on optimizing the localization algorithm. It is on schedule.
- What deliverables do you hope to complete in the next week?
We got a new IMU this week. Next week, I will incorperate the IMU with the current localization system to form a kalman filter.
- Verification
Since I mainly worked on the localization system, I need to make sure that distance measuring. The localization system itself is mentioned in Team’s Status Report and it needs to be tested with the whole team. In my status report, I will mainly discuss how to test distance measuring.
We have a laser measuring tool to measure the distances. First of all, set one of the anchors to a fixed position, and then start moving the tag from the anchor. Increase the distance about 5 meters each time and check if the tag measured distance is about the same as the distance that the laser tool measured (within 10cm deviations). I should continue to increase the distance until the distance reached the range of the UWB devices. I should repeat the test for measuring distances for multiple anchors. I should make sure that all of the distances measured are basically correct. I will also test in different situations such as signal blocks by walls and doors.