# DVL vs. (U)SBL for positioning **URL:** \ **Category:** General Discussion\ **Created:** [October 1, 2026, 12:50am UTC](https://discuss.bluerobotics.com/t/dvl-vs-u-sbl-for-positioning/23677 "2026-10-01T00:50:35Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![kurty](https://avatars.discourse-cdn.com/v4/letter/k/a4c791/32.png) [@kurty](https://discuss.bluerobotics.com/u/kurty)\ **Post date:** [October 1, 2026, 12:50am UTC](https://discuss.bluerobotics.com/t/dvl-vs-u-sbl-for-positioning/23677/1 "2026-10-01T00:50:35Z")
Looking for advice…what is the best way to put an ROV on an object if you have GPS coordinates? DVL vs. (U)SBL? ---
**Author:** ![tony-white](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/tony-white/32/18385_2.png) [@tony-white](https://discuss.bluerobotics.com/u/tony-white)\ **Post date:** [October 1, 2026, 2:30am UTC](https://discuss.bluerobotics.com/t/dvl-vs-u-sbl-for-positioning/23677/2 "2026-10-01T02:30:55Z")
Hi @kurty - I’m of the opinion that neither sensor type is strictly necessary - simply dropping a weight with thin line to a surface float at the target spot is typically enough to give you a reference to follow down and find your target. Making sure the line is just 10-15’ longer than water depth is important. A sonar like the Ping360 or the Omniscan FS is useful from there to find the object you’re after. I recently found this Algae array floating at 175m (in 400m of overall depth) simply by descending rapidly at the known coordinates, and spinning around at depth to find it with the sonar. It spotted it from 40m away! ![image](https://us1.discourse-cdn.com/flex019/uploads/bluerobotics/original/3X/5/f/5f0eba13d49330feecb2fd3276b712950a355674.jpeg) ![image](https://us1.discourse-cdn.com/flex019/uploads/bluerobotics/original/3X/6/2/626d22f81a4c480ded3c5af87cfa5cb2a1aaa10d.jpeg) If you insist on using a sensor, the DVL would need enough range to get bottom lock before descending. A USBL can give you 1Hz GPS position throughout, so is the best for finding a spot alone - however they work best when used together. ---
**Author:** ![ljlukis](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/ljlukis/32/3983_2.png) [@ljlukis](https://discuss.bluerobotics.com/u/ljlukis)\ **Post date:** [October 2, 2026, 1:20am UTC](https://discuss.bluerobotics.com/t/dvl-vs-u-sbl-for-positioning/23677/3 "2026-10-02T01:20:06Z")
Right on Tony! ---
**Author:** ![Hubert\_THOMAS](https://avatars.discourse-cdn.com/v4/letter/h/5e9695/32.png) [@Hubert\_THOMAS](https://discuss.bluerobotics.com/u/Hubert_THOMAS)\ **Post date:** [October 4, 2026, 3:35pm UTC](https://discuss.bluerobotics.com/t/dvl-vs-u-sbl-for-positioning/23677/4 "2026-10-04T15:35:20Z")
Hi Kurt, The answer is there [https://www.star-rtk.com/](https://www.star-rtk.com/) Do not hesitate to come back if you requie any further information, Hubert ---
**Author:** ![GavXYZ](https://avatars.discourse-cdn.com/v4/letter/g/dc4da7/32.png) [@GavXYZ](https://discuss.bluerobotics.com/u/GavXYZ)\ **Post date:** [October 6, 2026, 3:16pm UTC](https://discuss.bluerobotics.com/t/dvl-vs-u-sbl-for-positioning/23677/5 "2026-10-06T15:16:25Z")
I think USBL. We find the DVL doesn’t work well with thruster interference. I would agree with Tony that if you want to find something then a sonar may do the job but if you want to navigate to a position then I think USBL. ---
**Author:** ![kurty](https://avatars.discourse-cdn.com/v4/letter/k/a4c791/32.png) [@kurty](https://discuss.bluerobotics.com/u/kurty)\ **Post date:** [October 6, 2026, 4:04pm UTC](https://discuss.bluerobotics.com/t/dvl-vs-u-sbl-for-positioning/23677/6 "2026-10-06T16:04:35Z")
Thanks, Gav.