GPNS tracking nodes in the Port of Amsterdam on TTN Mapper

Just some fun fact: TTN Mapper shows quite a few GPNS tracking nodes in the Port of Amsterdam area, apparently operated by OBA Bulk.

As the map data takes a long time to load (typically about 6 minutes, but up to 20 minutes!), I won’t provide direct URLs here. But some yield nice images, especially a few probably semi-stationary nodes that seem to be showing that the calculated GPNS coordinates suffer some inaccuracy and rounding, of course. Like:

Stationary

Stationary

Stationary

Or, when seen from a specific gateway in Haarlem:

image

First I figured the above node may be a stationary reference for Differential GPS, or just a fixed reference to monitor some gateways. But both are unlikely, as there are many of those nodes to discover when following their naming scheme. Probably the above is just a GPNS node used elsewhere, which was temporarily taken inside an office or storage. Compare with, e.g, oba-gps-00020 which is clearly not stationary at all:

Not stationary

Also, it seems the nodes for the above maps have not been operational (or just not forwarding to TTN Mapper) recently. TTN Mapper will limit advanced maps to the most recent 10,000 “measurements”. For the above oba-gps-00003 I see those 10,000 most recent measurements spanning from 2020-03-17 09:40:04 thru 2020-03-18 11:25:56. And for oba-gps-00020 I see 2020-01-29 20:18:22 thru 2020-03-09 18:03:27. Each measurement is a single gateway, so a single uplink may yield multiple measurements. It seems that for those devices an uplink is/was transmitted every minute. Though we don’t know the packet size, on SF7 that’s probably within the legal maximum duty cycle, albeit not adhering to the 30 seconds TTN Fair Access Policy.

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Hey, thats my project.

What your seeing are the old nodes data. They are offline now for 3 months because i noticed the sending every minute probably not adhering to the 30 seconds of TTN. The new nodes should keep the 30s limit.
It is a custom made esp32 module with GPS, several inputs, outputs an RFID reader and 2 relays. We use it for authorisation and GPS logging on the terrain because the coal interferes with WiFi and other wireless signals. LORA seems to be fine in the area. The unit now limits the lora send rate on the gps coordinate speed in combination with the engine-running signal.
Also the gateway was just replaced from a Lorank8 with over 20 million packages to the new RAK outdoor gateway (2pcs).

If you still see any nodes not adhering to the 30s of TTN please notify me so I can change the firmware on the device.

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