# GPS jumping and not accurate in mission plan mode **URL:** \ **Category:** Uncategorized\ **Created:** [December 18, 2018, 6:09am UTC](https://discuss.px4.io/t/gps-jumping-and-not-accurate-in-mission-plan-mode/8908 "2018-12-18T06:09:54Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![acpl00](https://discuss.px4.io/letter_avatar_proxy/v4/letter/a/9dc877/32.png) [@acpl00](https://discuss.px4.io/u/acpl00)\ **Post date:** [December 18, 2018, 6:09am UTC](https://discuss.px4.io/t/gps-jumping-and-not-accurate-in-mission-plan-mode/8908/1 "2018-12-18T06:09:54Z")
Hi to every one I have a question about the GPS/Compass (3DR). In general, when I open QGroundcontrol station and I go to mission plan, I can see that the GPS position is not accurate, it is jumping even several meters from the position of the Drone. I am using Jetson TX2 and the GPS is quite close to it. I read that the USB3 port of the Jetson can cause disturbances in the GPS. Could be this the problem? More technically. I have QGC-Station and fly-mission-plan, when i set up all the points and I load the mission, I get the error ‘Unable to start mission (‘vehicle not ready’)’. In other words, I have tried position control and the drone responded quite satisfactorily using the RC transmitter. However, when I want to try fly mission mode, I can see that the GPS position is jumping even though the QGC takes up till 9 satellites, and the GPS is locked and the HDOP \< 1.5 and the VDOP \< 1.5. I can chose the way points and load the program but when I want to change to mission and arm I get the error: I get the error ‘Unable to start mission (‘vehicle not ready’)’. Do you have a clue about this 🙂 Thank you and looking forward to your replay ---
**Author:** ![rroche](https://discuss.px4.io/user_avatar/discuss.px4.io/rroche/32/17635_2.png) [@rroche](https://discuss.px4.io/u/rroche)\ **Post date:** [December 18, 2018, 6:32am UTC](https://discuss.px4.io/t/gps-jumping-and-not-accurate-in-mission-plan-mode/8908/2 "2018-12-18T06:32:06Z")
Hey @acpl00 are you flying with PX4? do you have access to your logs? ---
**Author:** ![acpl00](https://discuss.px4.io/letter_avatar_proxy/v4/letter/a/9dc877/32.png) [@acpl00](https://discuss.px4.io/u/acpl00)\ **Post date:** [December 18, 2018, 6:43am UTC](https://discuss.px4.io/t/gps-jumping-and-not-accurate-in-mission-plan-mode/8908/3 "2018-12-18T06:43:25Z")
Hi, Well I set the position flight mode over QgroundControl station, and the drone was flown with the RC-transmitter. I do not know where those log files are located 🙂 ---
**Author:** ![rroche](https://discuss.px4.io/user_avatar/discuss.px4.io/rroche/32/17635_2.png) [@rroche](https://discuss.px4.io/u/rroche)\ **Post date:** [December 18, 2018, 6:45am UTC](https://discuss.px4.io/t/gps-jumping-and-not-accurate-in-mission-plan-mode/8908/4 "2018-12-18T06:45:55Z")
First you have to determine which Autopilot are you running inside your flight controller, if you happen to be using PX4 then you can follow this guide [https://docs.px4.io/en/getting\_started/flight\_reporting.html](https://docs.px4.io/en/getting_started/flight_reporting.html) ---
**Author:** ![acpl00](https://discuss.px4.io/letter_avatar_proxy/v4/letter/a/9dc877/32.png) [@acpl00](https://discuss.px4.io/u/acpl00)\ **Post date:** [December 18, 2018, 6:54am UTC](https://discuss.px4.io/t/gps-jumping-and-not-accurate-in-mission-plan-mode/8908/5 "2018-12-18T06:54:23Z")
Yea I think it is px4, I will read that link, and what shall expect to see concerning the GPS and the error I get? ---
**Author:** ![rroche](https://discuss.px4.io/user_avatar/discuss.px4.io/rroche/32/17635_2.png) [@rroche](https://discuss.px4.io/u/rroche)\ **Post date:** [December 18, 2018, 4:23pm UTC](https://discuss.px4.io/t/gps-jumping-and-not-accurate-in-mission-plan-mode/8908/6 "2018-12-18T16:23:54Z")
Once you publish your logs follow the [GPS Uncertainty and GPS Noise & Jamming sections](http://docs.px4.io/en/log/flight_review.html#gps-uncertainty). I would also recommend posting a link here if you need assistance interpreting your logs. [http://docs.px4.io/en/log/flight\_review.html#gps-uncertainty](http://docs.px4.io/en/log/flight_review.html#gps-uncertainty) ---
**Author:** ![acpl00](https://discuss.px4.io/letter_avatar_proxy/v4/letter/a/9dc877/32.png) [@acpl00](https://discuss.px4.io/u/acpl00)\ **Post date:** [December 20, 2018, 9:46am UTC](https://discuss.px4.io/t/gps-jumping-and-not-accurate-in-mission-plan-mode/8908/7 "2018-12-20T09:46:53Z")
Hi rroche First at all, thank you for your kindly help 🙂 Secondly: Well, I read that USB3 is known to be an effective GPS jamming source. So, I have wrapped under the GPS and between the USB3 from Jetson TX2. And, amazingly The GPS status was as follows: GPS Count 17 GPS lock 3D DGPS lock HDOP 0.7 VDOP 1.1 Course over ground 219.4 However, when I set up or add way points in mission plan. I could successfully load the mission and when I wanted to start the mission I got the same error: ““Unable to start vehicle not ready”” Even though I tried few times just one log file is available. I read that the log files only generates when the drone is armed and disarmed, right? well, in that case I armed and disarmed the drone once with the RC-controller. But, the question is: How can get the log file if it does not allow me to arm and start the mission planer flight mode. I have the link that has been generated by the flight review. I share it here: [https://logs.px4.io/plot\_app?log=25769059-3f72-4431-bc6e-fd072442d7de](https://logs.px4.io/plot_app?log=25769059-3f72-4431-bc6e-fd072442d7de) Also, after I loaded the first mission plan and failed. I set up new mission plan and then when I wanted to load the way points mission, I got the error: ““Mission write failed to send final ack.”” I am looking forward to your replay.