JLINK LTE

[JAVAD Support]

JLink LTE is a family of devices designed for organizing a local network between different devices via WiFi, Ethernet, USB, Serial, and Bluetooth, and connecting to the Internet using 4G cellular digital communication services.
JLink LTE devices may contain 1-W radio module using either UHF (406 to 470 MHz) or ISM license free USA band (902-928 MHz).

JLINK LTE can be used as 'a hotspot / bridge' to allow a local connection to access the Internet via GSM cellular modem.
Thus, Link LTE can provide a solution linking the field GNSS equipment to RTN from the Internet (TCPO or NTRIP).



NOTE:
Please be aware that when using a JLINK LTE as 'a bridge' from Internet to UHF for corrections, that the retransmission period of 'corrections' over the UHF radio data link will be longer due to the limitation of the UHF radio modulation in use.
IE: Data Rates at 12.5 kHz Channel Spacing
o Modulation DBPSK/GMSK - 4800 bps
o Modulation DQPSK/4FSK - 9600 bps
o Modulation D8PSK - 14400 bps
o Modulation D16QAM - 19200 bps

 

[Sdrake14]

A new issue....the Jlink broadcasts for 30-40 minutes then arbitrarily the GSM signal quits and the status on the Jlink shows "no sims card" and "unregistered".
The issues appears to be from the modem and not the receiver since the status in the TCP tab of the Jlink still shows data incoming. The only fix found is reboot the Jlink then the SIMS reappears, unfortunately the WLAN receiver port now jumps from the Jlink 10.1.10.2 port required to a 192.168...etc and it requires resetting the receiver now to restart the corrections output. Then runs again for a similar period until the failure repeats.

Here are the 2 receivers Parameter configuration files attached (from NetView) with each of the Javad GNSS base unit setup . . .

 

[JAVAD Support]

The only fix found is reboot the Jlink then the SIMS reappears, unfortunately the WLAN receiver port now jumps from the Jlink 10.1.10.2 port required to a 192.168...etc and it requires resetting the receiver now to restart the corrections output.

Question: Do you have the receiver's WLAN setup to use a 'static' WLAN IP-Address with the JLINK 'hotspot' (IE: Disable DHCP)?

 

[Sdrake14]

Okay, so thank you John Rosco for all the help getting the Delta 3 base set up and running, along with the Jlink bridge for forwarding IP corrections into cell phone dead areas in the north woods! Things are pumping along as should be and we have rock solid corrections coming out of our new base setup.

I want to point out how we ended up with an NTRIP version of this base rather than my initial idea of using standard TCP port forwarding, this idea being shut down by my company's IT contractor who would not allow an open, unsecure, port on our file server system. He was okay with the idea of the more controlled NTRIP broadcast, so we shifted, and I so think I like it better, the multiple mount point scheme has allowed us to set one mount dedicated to the RTCM 3.2 broadcast for the Jlink use. This was because during Rosco and mine debugging/config/setup session based on Rosco's observing usual behavior in the radio latency on the rover, we discovered the Jlink could not handle incoming broadcast faster than 3 epochs, or maybe it was a bottle neck going out at it's UHF 9600 bps, but by turning the rate down on that mount point the Jlink function. This way the other Mounts stay at a 1 or 2 epoch broadcast for IP cell phone corrections. In the field it is as easy a switch as just changing the correction source from "cellular" to "UHF" and/or back, since the Jlink stays config'd to that mount point. The base ID remains the same.

The only problem I am now having is that we have discovered that is appears the Jlink does not like the new DAC3+ sims card. I can run it with a Verizon only static sim card but have it will not work with DAC3+. Spent hours on phone with tech support and he is convinced the bug is with Jlink. We did take the same DAC3+ card testing with and put it in the TLS+ rover and the card works as it should.

Any ideas John?

 

[JAVAD Support]

The only problem I am now having is that we have discovered that is appears the Jlink does not like the new DAC3+ sims card. I can run it with a Verizon only static sim card but have it will not work with DAC3+. Spent hours on phone with tech support and he is convinced the bug is with Jlink. We did take the same DAC3+ card testing with and put it in the TLS+ rover and the card works as it should.

The JLINK LTE unit uses the Sierra Wireless MC7304 module (w/GPS). The DAC3+ multicarrier SIM card appears to not be compatible with this module . . .



Note: When using the JLINK LTE for Internet RTN NTRIP to UHF radio 'data bridge', the MC7304 module (w/GPS) provides, to the NTRIP-Server, the approximate GGA position information (of the JLINK LTE unit) that is required for RTCM3.2 corrections (to the 'rover') . . .

Footnote: It is possible also to connect JLink to Internet via WiFi using any WiFi router, MiFi device or even smart-phone configured in hot spot mode.

 

[John Rosco]

JLink LTE configuration and accessories