Garmin eTrex SE accuracy

[darekk]

Recently I bought Garmin eTrex SE. I am sorry to write this, but it has very low accuracy in a forest. 20 m is standard, and sometimes it drops to 100-200 m. Is this normal or this receiver is defective ?
And first day being in Warsaw I landed in Taiwan ! Activity path was correct, in Warsaw, but waypoints in Taiwan.
For many years I've been using Garmin eTrex H, a very good receiver, with normal accuracy, in a forest from few to about 20 meters, maybe less.
I hope that the screenshots from Google Earth in this case are not a violation of Copyright. Manually clicked red lines are real routes.

Garmin_eTrex_SE_1.jpg

Garmin_eTrex_SE_1.jpg

Garmin_eTrex_SE_2.jpg

Garmin_eTrex_SE_2.jpg

[GPSrChive]

A few questions immediately come to mind...

• Which firmware version was your eTrex SE running for these events?
• Was Settings > Satellite configured for 'GPS Only' or 'Multi-GNSS'?
• Was the eTrex SE connected to a smartphone via Bluetooth?
• Where/How was the eTrex SE carried while these tracks were recorded?
• How long was the eTrex SE powered on and in clear view of the sky before recording these tracks?
• Can you share the recorded tracks?

[darekk]

Thank you for your answer.

• 4.20. It was installed using Garmin Express, but later the receiver asked question, whether I want install an updated version and it was installed again, eventually it was installed in two steps (Garmin Express, receiver's menu) (?). That was a little strange.
• First track 'GPS Only', second one 'Multi-GNSS'
• The eTrex SE was not connected to a smartphone via Bluetooth.
• The eTrex SE was carried in my pants pocket, upside down, because the lanyard is attached to the bottom of the receiver. I've always carried the eTrexH the same way and it worked well.
• In the first case the eTrex SE was powered on shortly on a bus-stop on a street with sparsely growing large trees, after that was turned off and later 1.2 km from this place (waypoints 1 and 2) it was turned on again on a street between two small meadows surrounded by a forest. I was taking pictures of plants when eTrex SE was acquiring the signal, not waiting for the message ready for navigate, moving within a radius of approximately 10 m or a little more.
  In second case in the vicinity of another bus stop (waypoint 1), taking pictures of plants on such dry grass, I think that not waiting for the message ready for navigate, moving within a radius of approximately 10 m. Trees were on the other side of street, 20-30 m from this place.
  On both bus-stops during acquiring satellite signals as usually I pushed buttons Settings - System - Reset - Reset Trip Data and - Clear Recording.
• The recorded tracks are here:
  Garmin_eTrex_SE_1.gpx

  https://darekk.com/temp/GPS/Garmin_eTrex_SE_1.gpx
  (the same, but on connect.garmin.com)

  https://connect.garmin.com/modern/activity/15933493948
  Garmin_eTrex_SE_1_clicked.kml (manually clicked parts of the real track)

  https://darekk.com/temp/GPS/Garmin_eTre ... licked.kml
  Garmin_eTrex_SE_2.gpx

  https://darekk.com/temp/GPS/Garmin_eTrex_SE_2.gpx
  Garmin_eTrex_SE_2_clicked.kml (manually clicked parts of the real track)

  https://darekk.com/temp/GPS/Garmin_eTre ... licked.kml

[RunnerAndrew]

Hi some of your issues could be down to GPS jamming that may be happening in your area as per this article , hopefully not but could be a possibility

[darekk]

What is GPS jamming ?

[lost]

Spoiler

https://www.flightradar24.com/data/gps-jamming

Spoiler

https://gpsjam.org/?lat=53.34611&lon=14 ... 2023-12-31

Here are two pages that show which areas are affected by GPS jammers.

I don't know much about this but gps jammers are often used to make it harder to fly drones and stop gps trackers.

[RunnerAndrew]

I linked to an article but the link has been removed , this is the text copied from the article in relation to possible GPS jamming:

Electronic warfare: Russia’s GPS jamming in Poland
By Arie Egozi

Russian tests with special electronic systems resulted in GPS interferences over Poland last month. According to a report on the website of the Middle East Media Research Institute (MEMRI), on January, Global Positioning System (GPS) disturbances were recorded over the eastern territory of Poland, particularly covering the Suwałki Gap.
Krasukha electronic warfare system. Photo: Ministry of Defence of the Russian Federation.
Russian tests with special electronic systems resulted in GPS interferences over Poland last month. According to a report on the website of the Middle East Media Research Institute (MEMRI), on January, Global Positioning System (GPS) disturbances were recorded over the eastern territory of Poland, particularly covering the Suwałki Gap.

Previously, aircraft flying over the Baltic region reported issues in GPS function. Several media outlets attributed the issues to the Russian Army testing electronic weapons. On January 16, the Press Service of Russia’s Western Military District announced that the Baltic Fleet was carrying out a military drill to protect command posts from enemy UAV strikes.
The exercise made use of electronic warfare (EW) systems RB-341V Leer-3 complex and Pantsir-S1 anti-aircraft missile and gun systems. During the exercises, a protective ‘dome’ with a radius of several dozen kilometers was created by the EW systems. In total, according to the Russian Defence Ministry, the event involved about 100 servicemen and about 10 vehicles

[GPSrChive]

Thank you for posting the following responses:

• 4.20. It was installed using Garmin Express, but later the receiver asked question, whether I want install an updated version and it was installed again, eventually it was installed in two steps (Garmin Express, receiver's menu) (?). That was a little strange.

Virtually all Garmin devices operate this way. In your case, the firmware update package was loaded to the device via Garmin Express, then when the device next reboots, it finds the update bundle and asks the user if they want to install it. This is when the update is actually written to the internal operating system. Once completed, the device will again reboot to apply the new update.

• The eTrex SE was not connected to a smartphone via Bluetooth.

This indicates the device had no method of loading an updated EPO (Extended Prediction Orbit) file for the new location it found itself in. This file is not required for normal operation, but it does help the device find available satellites and locate current position within seconds instead of minutes.

• The eTrex SE was carried in my pants pocket, upside down, because the lanyard is attached to the bottom of the receiver. I've always carried the eTrexH the same way and it worked well.

This is probably the worst way to carry this device. The GNSS patch antenna is located directly under the front glass panel, just above the display. During 'normal' or 'expected' operation, most users will hold the device out in front of them, with the display facing upward and the top toward the sky, keeping the antenna in a perfect location to receive satellite signals unobstructed.

Having the device upside down inside a pocket with the display firmly pressed against your body greatly inhibits the antennas ability to receive satellite signals effectively. Our bodies are composed primarily of water and therefore very effective at obstructing radio signals.

The heavy foliage you were under also contains a large amount of water to obstruct the satellite signals even before they made it to your pants, where the receiver was located.

The eTrex SE is equipped with a spine mount that allows for many mounting options. I strongly suggest finding a better solution that allows you to carry the device top up and face out when not in hand. (multiple options can be found here).

• In the first case the eTrex SE was powered on shortly on a bus-stop on a street with sparsely growing large trees, after that was turned off and later 1.2 km from this place (waypoints 1 and 2) it was turned on again on a street between two small meadows surrounded by a forest. I was taking pictures of plants when eTrex SE was acquiring the signal, not waiting for the message ready for navigate, moving within a radius of approximately 10 m or a little more.
  In second case in the vicinity of another bus stop (waypoint 1), taking pictures of plants on such dry grass, I think that not waiting for the message ready for navigate, moving within a radius of approximately 10 m. Trees were on the other side of street, 20-30 m from this place.
  On both bus-stops during acquiring satellite signals as usually I pushed buttons Settings - System - Reset - Reset Trip Data and - Clear Recording.

I think if you were to recreate these trips following the advice provided above, with Settings > System > Satellite configured for Multi-GNSS, you would be able to achieve much more favorable results.

[darekk]

Having the device upside down inside a pocket with the display firmly pressed against your body

Display was was facing outwards, not the body.

with Settings > System > Satellite configured for Multi-GNSS

During second trip Multi-GNSS was set.

[darekk]

This indicates the device had no method of loading an updated EPO

I found in the internet, that a smartphone is not needed. This device was many times synchronized with Garmin Express on the PC. So EPO should be up to date and this is not the reason of 200 m error. However today I deleted CPE.bin and EPO.BIN from the RemoteSW folder, disconected the device from the computer and connected again. After synchronisation perforemed by Garmin Connect, CPE.bin appeared again in this folder, but not EPO.BIN. This is very disturbing.
It is also a little strange, that information about EPO and CPE is not available under Settings - About.
EPO.bin can be downloaded also with

getEPO.exe (I hope, that this third party software is safe, because it is not Garmin's)

http://www.gpsrchive.com/Shared/EPO/EPO.html

and manually copied to RemoteSW folder. I did this. New EPO.bin has exactly the same size (64512 bytes) as old one, from May, what suggests, that nothing changed in EPO (?).
But anyway, EPO is not the issue here.