External Satellite Navigation System antennae

[kas_1611]

My Raymarine Chartplotter frequently loses signal lock and I was thinking about using an external antenna instead of the internal one in the hope of a) geting a better lock and b) accessing Glonass and Galileo as well as GPS satellites.

Raymarine do a "plug and play" STng antenna for their system but it only receives the GPS signal so not much benefit there. Even with the ease of adding it to the system.

So the question is are there any NMEA2000 external sat nav antennae out there that pick up 2 of the 3 or better all 3 satellite constellation signals? There is a conversion kit available to add NMEA2000 devices to the proprietary Raymarine STng system.

Cheers

Keiron

[travellerw]

I don't know any antenna that pick up the Galileo satellites. This B&G does both GPS and Glonass.

B & G ZG100 External GPS Antenna Package

P.S. It comes in the Triton instrument pack, just in case you "need" to replace those devices

[barnakiel]

GLONASS (and/or) GPS sensor:

Digital Yacht - GPS Sensors

and

Raymarine Networking

and you are set.

PS Note this is n183 output and so your networking has to allow for this.

PS2 You can get N2K glonass and gps from any decent smartphone.

b.

[hellosailor]

A cursory web search shows the Galileo satellites use an L1 frequency of 1575.42MHz, and that's exactly the same as the UPS GPS system.


I would expect any antenna that picks up US GPS satellite signals will work just fine with the Galileo system, unless there are other frequencies that are very different.

If some customer-service droid is just reading a manual that was written five years ago...even if that works with Galileo, they won't know or say anything about it, since that would never have been documented five years ago, and would often not be updated for "obsolete" products since.

Anything that puts a "signal" onto an NMEA bus of any kind, will NOT BE AN ANTENNA. The NMEA systems handle data, and an antenna does not output formatted NMEA data. You'd need a full-blown GPS to output position strings, etc. to connect to an NMEA bus.


For an external antenna, go with what the manufacturer offers. Little else is likely to be compatible, it is likely to ruin the equipment.


Sadly there's little way to tell what is an "antenna" and what is a full gps (without a local display) and the industry makes little attempt to enlighten customers about that.

[karle]

Does your chartplotter support external bluetooth GPS receivers? There are plenty of good ones available at very reasonable prices on Amazon.

Originally Posted by kas_1611

My Raymarine Chartplotter frequently loses signal lock and I was thinking about using an external antenna instead of the internal one in the hope of a) geting a better lock and b) accessing Glonass and Galileo as well as GPS satellites.

Raymarine do a "plug and play" STng antenna for their system but it only receives the GPS signal so not much benefit there. Even with the ease of adding it to the system.

So the question is are there any NMEA2000 external sat nav antennae out there that pick up 2 of the 3 or better all 3 satellite constellation signals? There is a conversion kit available to add NMEA2000 devices to the proprietary Raymarine STng system.

Cheers

Keiron

[kas_1611]

Originally Posted by karle

Does your chartplotter support external bluetooth GPS receivers? There are plenty of good ones available at very reasonable prices on Amazon.

Sadly no Bluetooth system but good idea. I've been using a BT GPS gizmo for my Mac for a few years now but have to say I haven't seen anymore satellites on it than my chart plotter so it is probably GPS only.

Apparently the manufacturers of my chart plotter are not intending to make a Glonass compatible antenna anytime soon, which I feel is a pretty poor showing when my mobile phone can pick up GPS and Glonass to give me up to 30 satellites at a time for a stable, high accuracy fix (and before anyone says Assisted GPS the data is off as is the wifi). If our phones and tablets can pick up both systems then surely it isn't too much to ask that our primary navigation and safety equipment should be able to as well.

[Dockhead]

Originally Posted by hellosailor

I would expect any antenna that picks up US GPS satellite signals will work just fine with the Galileo system, unless there are other frequencies that are very different.. . .

Antenna yes, but receiver no. For a GNSS receiver to use a given navigation system, it needs not only to be able to receive the signals, it needs to be able to decode and process them. GPS receivers will not process Galileo signals. However, the new Simrad/B&G GNSS receivers do work with Galileo, or rather, will do so, when Galileo is available starting maybe next year some time. Galileo is not currently operational.

[hellosailor]

kas-
As dockhead points out, processing the new systems is very different from receiving them. The software in a system would need to keep ephemeris and almanac data (did I remember that right?) for both new systems, and to make sense of the identities of all the new satellites, not just "more signals" on the same frequencies.


Rashly assuming the GPS unit was built to a price, it has limited program storage memory, a limited CPU, and quite possibly the program is in ROM that cannot be updated. After all, there was no need for it at the time, and little need even now.


So...and do remember, please, that Samsung's first "Galaxy" phone series in the US (the Samsung AT&T Captivate) was unable to process GPS signals correctly at all. They shipped with defects, they lied about correcting the defects at least twice in "updates", and if you tried to use the A-GPS feature, it was hard programmed to use an A-GPS server that Samsung had actually SHUT DOWN before the phones ever shipped. Six months later they were still issuing updates pointing to their dead server, and you wouldn't know they were lying unless you accessed the secret service menu on the phone. Where you could indeed change the server name and make the feature work. (Although, the GPS often never did in any case.)


This is why the coffee pot on a B1 bomber is so expensive. But it will never shatter when dropped, the way your consumer-grade Mr. Coffee or Krups will.(G)

[kas_1611]

The newer A and E class chartplotters do access the Glonass system but it seems the popular C class plotter is not on the list to be upgraded any time soon so it looks like I'll just have to put up with the frequent "loss of position fix" unless I want to spend a few thousand squids on a new system.

As for the B1 coffee pot being so expensive one has to ask why they did just use a metal pot? Bit like the NASA pen that writes upside down, in zero gravity and underwater that cost billions to develop but the Russians just used a pencil

Thanks for all the inputs and help

Keiron

[hellosailor]

I've been a pencil fan for many years. Since a classic Bic "Crystal" leaked all over when I forgot it was in a pocket and fell asleep one hot summer night. And later when I discovered pencils don't freeze in the cold either. Our FBI also used to say that the most permanent thing you could write with was a pencil, the graphite fibers embed in paper and can later be traced much more reliably than any ink which can be bleached of dissolved out.


And being a pencil can, I can also say that a space pen (made by Fisher, only sometimes used by NASA, mainly Fisher's advertising genius that established the confusion) never needs to be sharpened. Ever see what happens when a hand-cranked pencil sharpener has to be emptied, and it takes a dump all over?

Horses for courses.

[barnakiel]

Yep. Galileo we will see. But Glonass is already here and our Samsung mobile uses the constellation. Some handheld Garmins too.

Also the "antenna" (which in facts holds a receiver inside) I posted above is a G and/or G device. I am getting one for my ship. Can be used as a low power position source for VHF, AIS, etc as well as an emergency positioning device (with some sort of PC or a tablet).

If I get it any time soon I will post here what results.

b.

[Dockhead]

Originally Posted by barnakiel

Yep. Galileo we will see. But Glonass is already here and our Samsung mobile uses the constellation. Some handheld Garmins too.

Also the "antenna" (which in facts holds a receiver inside) I posted above is a G and/or G device. I am getting one for my ship. Can be used as a low power position source for VHF, AIS, etc as well as an emergency positioning device (with some sort of PC or a tablet).

If I get it any time soon I will post here what results.

b.

Does anyone know how current GNSS receivers are using GLONASS? My equipment doesn't tell me anything because the menus and displays were designed for pure GPS. Even with recent software updates, my Zeus displays refer to position data source as "GPS Source" and display only GPS satellite signal bars.

My GS25 gets EGNOS and the system DOES way that I have a "WAAS Fix".


But I can't tell whether the system is doing anything with GLONASS. Are these systems averaging position calculations from both constellations? Or how does it work?

We have a couple of experts in this community (like Dave "Goboatingnow"); maybe someone will chime in and enlighten us.

[Alan Mighty]

Originally Posted by Dockhead

Does anyone know how current GNSS receivers are using GLONASS? My equipment doesn't tell me anything because the menus and displays were designed for pure GPS.

...

But I can't tell whether the system is doing anything with GLONASS. Are these systems averaging position calculations from both constellations? Or how does it work?

In the handheld device market, the major chipset manufacturers (Qualcomm, Broadcom, MediaTek, uBlox, CSR etc) have worked hard to incorporate everything available (GPS, Glonass, BeiDou, QZSS etc).


Broadcom, currently regarded by industry watchers as the No. 2 GNSS chipset provider, has issued low tech press releases touting their chipsets and their workings. Broadcom suggests that their BCM47531 chipset looks at all the GNSS data available (GPS, Glonass, BeiDou, QZSS, SBAS etc), compares them, and rejects whichever is not in accord with the others. That means, for example, that bad ephemeris data from one of those services can be/has been identified and ignored


For an example see: https://www.broadcom.com/blog/wirele...lation-outage/


Al

[Dockhead]

Originally Posted by Alan Mighty

In the handheld device market, the major chipset manufacturers (Qualcomm, Broadcom, MediaTek, uBlox, CSR etc) have worked hard to incorporate everything available (GPS, Glonass, BeiDou, QZSS etc).


Broadcom, currently regarded by industry watchers as the No. 2 GNSS chipset provider, has issued low tech press releases touting their chipsets and their workings. Broadcom suggests that their BCM47531 chipset looks at all the GNSS data available (GPS, Glonass, BeiDou, QZSS, SBAS etc), compares them, and rejects whichever is not in accord with the others. That means, for example, that bad ephemeris data from one of those services can be/has been identified and ignored


For an example see: https://www.broadcom.com/blog/wirele...lation-outage/


Al

Thanks. That's really interesting.

It's a very recent chip, and a smartphone chip, so not necessarily an indicator of how our receivers work, but I hope it's something like that.

The ability to receive diverse constellations and intelligently combine or choose between the data seems to me like a huge leap forward, making pure GPS receivers somewhat obsolete. A huge leap forward in reliability, and ought to give much higher accuracy. These things are much more important now since we all rely heavily on chart plotters for life-safety critical pilotage.

[barnakiel]

Originally Posted by Dockhead

Does anyone know how current GNSS receivers are using GLONASS? My equipment doesn't tell me anything because the menus and displays were designed for pure GPS. Even with recent software updates, my Zeus displays refer to position data source as "GPS Source" and display only GPS satellite signal bars.

My GS25 gets EGNOS and the system DOES way that I have a "WAAS Fix".


But I can't tell whether the system is doing anything with GLONASS. Are these systems averaging position calculations from both constellations? Or how does it work?

We have a couple of experts in this community (like Dave "Goboatingnow"); maybe someone will chime in and enlighten us.

Server side GLONASS sentence is GL, GPS sentence is GP, how your (client) equipment labels the entry is up to this equipment's software.

The antenna I linked is user set'able for either Glonass or GPS (or for both to be used simultaneously). You can email the company and sure they will share some further info.

I think I might be able to spit some Samsung positioning data as nmea via TCP. I will try to make a test. If I get any insight, I will re-post here.

I have seen online tests of street gps/glonass units that clearly showed higher accuracy (in city canyons).

Cheers,
b.