Servers by jDrones

Global Satellite Telemetry for ArduPilot


(Perth UAV - Sam) #21

We only used one 4G modem at the time and went out and tested both the Optus and Telstra networks by swapping static IP SIM cards at the nearest main road near the remote landing site. The Optus network was best there, but didn’t really want to work under 50cm above the ground. Our aircraft was only 2kg and therefore only 25cm high. Didn’t look good. :frowning:

Our last minute idea was to mount it on one of the main wing tips, and then only have one leg on one side of the aircraft, so when it landed it tipped to one side and so that on the other wing tip with the 4G antenna would be higher off the ground.

(Pavel Bobov) #22

Here is a graph of signal quality reported by my RockBLOCK with patch antenna for 100 minutes period with 1 minute sampling interval.

(Perth UAV - Sam) #23

Thanks Pavel!
That is actually really useful to see. So about 4-5minutes of no reception being the longest, but a period of about 30minutes of fairly patchy reception. Not Ideal, but probably useable still. How long does it actually take to send a message if it does have reception? 10-20 seconds? And from what signal quality upwards will it still send roughly?

(Pavel Bobov) #24

The software does not try send/receive sessions if the signal quality is <2. The sessions usually succeed with signal quality >=2 and take about 10-20 seconds.

I’m curious how antenna affects the signal quality. What makes a good antenna for 1600MHz?

(Perth UAV - Sam) #25

Hmm ok. That makes it a fair bit worse. About 40-45% offline. About 6-7minutes at a time offline. Probably no certainty with the satellite coverage, so it could be up to 30-40min worse case. In air would be probably better, but for the challenge we don’t need it in the air at all with the RFD900 available.

Antenna would be critical, as would RF noise floor and a good ground plane. Not sure what sensitivities they operate at, but it’s probably similar to GPS. Stephen would know more.

(Stephen) #26

Since RockBLOCK uses the Iridium L-band service (1616-1626 MHz), it operates very close to the GPS band. I suspect any GPS antenna would work quite nicely. There’s plenty of commercial antennas for Iridium around, like

Iridium signal power would be higher than GPS (at the Earth’s surface). Any Iridium modems would have had great care taken not to interfere with the GPS.

In summary:
-Iridium won’t interference with GPS, assuming you’re using off-the-shelf equipment
-Noise floor would be similar to GPS

(Pavel Bobov) #27

I’m about to order GA™ 38 GPS/GLONASS Antenna.

(Pavel Bobov) #28

I could not make my RockBLOCK work with GA™ 38 GPS/GLONASS antenna. As soon as the external antenna is attached and the patch antenna is shielded, the signal quality becomes flat zero. It work pretty well though with pretty much any other piece of metal used as antenna.

(Pavel Bobov) #29

Here is the actual data reported by RockBLOCK during a 2 hours, 120 miles car trip with reporting period set to 60 seconds.

Click on the arrow markers to see HIGH_LATENCY message attributes for the position.

The magnetometer was not calibrated, so the heading values are off the chart.

The report also demonstrates SPLStream and SPLTracks web services recently added to the SPL software suite.

(Perth UAV - Sam) #30

Thanks for that Pavel. It does give a good indication of the Irdium performance. There’s not to many position points missing from what I can tell on the map. Looks good, I think it should work.

(Pavel Bobov) #36

Intel discontinues Arduino 101 along with Joule, Galileo, and Edison product lines. Raspberry PI, here I come.

(Pavel Bobov) #37

SPL v2.0.0 is released. SPL Radio Room is now supported on Raspberry PI.

(Ryan Nolin) #38

Great! I will be giving this set up a try soon.

(Derek Williams) #40

Very cool project. Is there any sort of guide for a total n00b to set this up if you have the hardware (autpilot, RPi, and RockBlock 9603) but no idea where to start?

(Pavel Bobov) #41

The installation and operations instructions for SPL are available at

Questions and suggestions should be posted to the discussion forum at