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traccar-test-01 [2020/04/14 08:25] |
traccar-test-01 [2021/04/13 06:54] (현재) |
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+ | < | ||
+ | {{: | ||
+ | Code (Finding ghosts): [[https:// | ||
+ | [[traccar-test-01-kr|한국어 문서/ | ||
+ | |||
+ | ===== Intro ===== | ||
+ | We have been studying differences of daily activity between disable people and non-disable. So, we had to gather people' | ||
+ | |||
+ | Anyway, we adopted Traccar as our GPS tracking platform base, and we'd already tried several experiments. It worked well, but we got a bad news recently. \\ | ||
+ | ===== What's the problem? ===== | ||
+ | GPS is only available outdoors.((In fact, today' | ||
+ | |||
+ | Today' | ||
+ | So, we got some potential issues: | ||
+ | * Most of data doesn' | ||
+ | * The tracker device are so varied. It is so hard to comprehend. | ||
+ | |||
+ | Besides, it is sufficient so that we can get the places our participant visits, although we don't catch actual location where they are in each place. | ||
+ | ===== There is a gap! ===== | ||
+ | {{:: | ||
+ | |||
+ | While we believe we know the testers' | ||
+ | * Is there any critical gap? Have we missed a lot of the data? | ||
+ | * If not, our data are really safe? | ||
+ | * What causes the gaps? Should we prevent the gaps? | ||
+ | |||
+ | We must look into which was right. | ||
+ | ===== Test ===== | ||
+ | Unfortunately, | ||
+ | |||
+ | Test starts: 20190121 | ||
+ | ^Name^Phone^OS Ver.^Traccar Ver.^Network^Major problem^ | ||
+ | |DBLAB0102|iPhone 6|12.1.2|5.5 (latest in iOS)|Only Wi-Fi (tethered to other phone' | ||
+ | |DBLAB0103|Samsung Galaxy S5|6.0.1|5.17 (latest in Android)|Only Wi-Fi (tethered to other phone' | ||
+ | |||
+ | Both devices have sent location data for a week. | ||
+ | To get more information, | ||
+ | |||
+ | ===== Result and Analysis ===== | ||
+ | We configured the client to send its location every 60 seconds. Theoretically, | ||
+ | ^ ^ < 2 min ^ 5 ^ 30 ^ 60 ^ 120 ^ 180 ^ 360 ^ > 360 ^ total ^ % of < 2 min ^ | ||
+ | ^DBLAB0102| 5095 | 49 | | ||
+ | ^DBLAB0103| 8852 | 144 | | ||
+ | Although the iPhone(0102)' | ||
+ | ==== Case 1: Low battery and shutting down ==== | ||
+ | Low battery example: DBLAB0102' | ||
+ | ^index ^ servertime ^ devicetime ^ | ||
+ | ^284| 2019-01-21 14: | ||
+ | ^285 (Gap)|2019-01-21 18: | ||
+ | ^286| 2019-01-21 18: | ||
+ | |||
+ | Traccar client spend the network data and battery, more or less. Old phones usually have smaller battery size than brand-new ones. We have already planned for the battery issue by providing additional battery to participants. Still, we need a tracking system that can save more energy and alert the battery getting low. | ||
+ | * Some data could be missed if the participant would have not recognized the battery level. | ||
+ | ==== Case 2: Low battery and energy saving mode ==== | ||
+ | Energy saving example: DBLAB0102 (#119) \\ | ||
+ | ^index ^ servertime ^ devicetime ^ | ||
+ | ^46| **2019-01-21 10: | ||
+ | ^47 (Gap)|2019-01-21 10: | ||
+ | ^48| 2019-01-21 10: | ||
+ | |||
+ | This case occurred twice on DBLAB0102 (iPhone). iOS seems to have got a kind of procedure that halts power-consuming process for a while. It may have a relation to the case 3. We have not founded the case 2 on Android phones yet. | ||
+ | * Some data could be missed if the participant would have not recognized the battery level. | ||
+ | ==== Case 3: Process killed/ | ||
+ | **Traccar blocked: DBLAB0102 (#1666)** | ||
+ | ^index ^ servertime ^ devicetime ^ | ||
+ | ^1664 | 2019-01-23 03: | ||
+ | ^1665 (Delayed)| **2019-01-24 08: | ||
+ | ^1666 (Gap)|2019-01-24 08: | ||
+ | ^1667| 2019-01-24 08: | ||
+ | |||
+ | It is critical issue. You can see #1737 data sent after unblocking Traccar. (#1738) The circumstances like this can also be shown Case 4, but the system unblock automatically in that case. We must prevent this case.\\ | ||
+ | iPhone blocks a process that uses power and data continuously. As I know, the only way to unblock Traccar is to wait until iphone shows a pop-up asking whether keep blocking the process. The default option (right side) is block. If the participant are unaware, he will tap " | ||
+ | |||
+ | * iPhone: Some data could be missed if the participant would have clicked pop-up unconsciously. | ||
+ | * Android (Samsung): Some data could be missed if the participant would have turned off energy saving options in advance. | ||
+ | ==== Case 4: Sleep mode/idle ==== | ||
+ | ^index ^ servertime ^ devicetime ^ | ||
+ | ^718 (Delayed) | **2019-01-22 08: | ||
+ | ^719 (Gap)|2019-01-22 08: | ||
+ | ^720| 2019-01-22 08: | ||
+ | |||
+ | We can see server got two locations #118 and #119 at once because OS blocks sending position #118 so that Traccar client update the local location like #118 but it'd not sent. Unlike Case 3, however, the device resend the data spontaneously in this case. We've spotted a lot of idle mode delays. All of this case, the devices have no movement when they connected known Wi-Fi at home or in the office. Usually, the owner was sleeping or working inside. | ||
+ | * Safe. But, there could be a lag for recalibrating GPS signal. | ||
+ | * If the user didn't go outside for a long time, we could be misunderstood this case as Case 3. | ||
+ | |||
+ | ===== Summary ===== | ||
+ | * Most gaps caused by sleep/idle mode of the operating system. There is no data loss unless the user forgot carrying his phone. | ||
+ | * The user must experience the device blocks Traccar because of its power consumption. It is usually three days after. We need to make sure the participant' | ||
+ | * Battery issue is not trivial. | ||
+ | |||
+ | ===== Future works ===== | ||
+ | * This is data about locations. We need to make some visualization tools with Korean maps. Traccar supports google and openstreetmap but they have some deficiencies because of legislations. | ||
+ | * We also need monitoring system for notifying users to prevent any data loss. | ||
+ | * All participant have to take a pre-test period at least three days. We could assure Traccar working on the device fine. |