GNSS Antenna

A receiver can be geofenced, but I don't think a separate antenna can, as it doesn't have any smarts.

Antennae have specific freq responses. So a GPS antenna works world wide. A GLONASS GPS GALILEO antenna works world wide. The receiver has to be compatible. Most (probably all) require a DC voltage supplied on the antenna cable. Antenna may require 5 vdc or have 5-18 vdc tolerance.

So itƒ??s the receivers compatibility and what GNSS satellite system itƒ??s capable of.?ÿ

@bill93?ÿ

Thanks mate, is there any way of determining if the receiver is or not?

A GNSS receiver will clearly state if itƒ??s GPS only, or GPS/GLONASS compatible, or Galileo and/or BeiDou. And what DC voltage is supplied on the antenna socket. ?ÿ

the antenna specs will also specify if its ?ÿfreq range includes GLONASS Galileo etc. And what DC voltage it requires and whether itƒ??s specific voltage or regulated to accept a range of voltage.

my antennae can accept 5-18 VDC. One of my receivers supply 9 VDC, and another is 5 VDC. No requirements for location. Iƒ??ve taken them to Asia South America China.?ÿ

Just about all current GNSS antenna are ƒ??activeƒ??, which indicates the antenna has a pre-amp, which is why it requires a DC bias supplied in the coax lead.

I use different brands of older antennae, gps only, interchangeably.

Posted by: @zammo

Thanks mate, is there any way of determining if the receiver is or not?

Sure. Buy it, receive it, set it up and turn it on. It will tell you.

Seriously - approach your friendly neighborhood dealer with the unit's serial number and they can look it up. That said, there is almost no price savings level at which I would risk making a purchase from an overseas dealer. Just too risky for my blood. Nevertheless, I am not above using that overseas price as leverage to get a better deal from my local dealer.?ÿ?ÿ

@norman-oklahoma You canƒ??t be serious. The documentation of the instrument which you can read in advance.

And GNSS instruments are not specific to Europe or Asia or South America.

So, post a specific brand and model of receiver and antenna you are interested in and get comments here.?ÿ

Posted by: @larry-scott

You canƒ??t be serious.

Quite serious. I'm not buying from an overseas dealer. I'd be totally at the mercy of someone who I did not know and had no realistic chance of even finding - much less bring to account -?ÿ if things go sour. Not worth it. I'm a surveyor, not an international trade broker.

I'm also serious about inquiring of the manufacturers representative about the licensing status of an individual unit. That is why - one reason at least- they are serial numbered in the first place.?ÿ ?ÿ

@norman-oklahoma?ÿ

Then donƒ??t buy from a dealer overseas. Ok. Plenty of us take our US procured GPS/GNSS kit and work internationally without issue. So, Iƒ??m unaware of a geo-locked GNSS receiver or antenna. Now as for service or support an overseas dealer may pose difficulties. Thatƒ??s a different issue.?ÿ

Maybe someone can cite an example of geo-locked receiver or antenna. That would be good to know. Iƒ??ve taken my receivers world wide. Geo-locked kit has never come up.?ÿ

Posted by: @larry-scott

Plenty of us take our US procured GPS/GNSS kit and work internationally without issue. So, Iƒ??m unaware of a geo-locked GNSS receiver or antenna.

I would not expect a US procured (or Australia/NZ, western Europe, etc.) unit to be geofenced. A unit originally sold new in a third world country - at a price well below US market - might well be. I have no personal experience with that but I understand that it is done. If I can't get a great price why would I even consider buying something from an overseas dealer? And if the price is that great maybe there is a reason.?ÿ ?ÿ

@norman-oklahoma?ÿ

Verifying the serial number with a dealer sounds like a good way to avoid the pain, I spoke to a friend the other day and he mentioned that it's really hard to get new equipment in general at the moment, but the last thing you want is for the unit to refuse to work because it's restricted to only function in a certain region.

@norman-oklahoma?ÿ

well if there are geolocked GNSS receivers, Iƒ??d like to see a citation of that. And that would definitely be in the documentation.?ÿ

Pardon the intrusion, but Topcon receivers allow the area in which they will operate to be set by defining a "window" by latitudes and longitudes.?ÿ That said, I have never seen one with such a limit set in it.?ÿ The OAF (Options Authorization File) that enables the various licensed capabilities of the unit has a list of several lat/long inputs.?ÿ I did not see a way to set those values in the Options file.?ÿ I believe those values may be present to prevent the equipment from working in places where its use is prohibited.?ÿ

@jerrys I looked thru several manuals and the OAF settings. I did not find any reference to a ƒ??windowƒ?? of operation. More importantly, in the manuals under trouble shooting for issues of lack of reception or operation, there is no mention of being outside a ƒ??window of operationƒ??. So if the receiver were subject to a regional restriction surly that would be part of the trouble shooting FAQ.

Again, Iƒ??ve worked in other countries and with surveyors from other countries that had their kit, and have never heard of a lock out by lat long licensing or restriction. As you said, you didnƒ??t see it in the OAF. ƒ??I did not see a way to set those values in the Options file.ƒ?

maybe thereƒ??s an ITAR or ODTC regulation re: exporting controlled technology to conflict zones, but having worked in NATO conflict zones no such issue was encountered.

When I went to China 20 yrs ago we were not permitted to take our geodetic L1/L2 receivers. However China had NAVSTAR GPS receivers and that data ran thru my post processing software without issue.?ÿ

Here are 2 OAF files. One appears to be unrestricted in the Lat Longs while the other appears to have some limitations.

?ÿ

@lurker interesting.

the question is: is that user input, and does that terminate operation.

I donƒ??t know what to make of that. My Ashtechs (z12 an ZSurveyor) no such settings.?ÿ

@larry-scott No that is not user input. It is the printout of an Options Authorization File. These came from a dealer and I'm not sure what influence a dealer has on them. I suspect they originate from Topcon with the dealer only being a conduit. The receiver is fully capable but Topcon then limits its functions with the OAF. If you pay for it, Glonass for example, then that option will be enabled by the OAF. It appears they can restrict the areas the receiver will produce a solution by those Lat. Long. values. I only showed a portion of the file. There are about a hundred different items addressed by the OAF including the ability to make the receiver unusable after any given date.?ÿ

I firmly believe it is possible to geofence gnss units. What manufacturers do it, I don't know.

@lurker Chalk one up for older kit: unrestricted.

Everything is subscription these days.?ÿ

I don't think this has to do with subscriptions.?ÿ With the exception of optional maintenance plans, I do know of any survey kit that requires a subscription (I understand some photogrammetry sensors do).?ÿ Without digging an old 4000SSi out of the attic, I recall that they could be location locked by Trimble.?ÿ Attached is the licensing for one of my GS16s.?ÿ Clearly, they can limit the location of use as they have a license for 'No area limitation'

?ÿ

When I was dealing with purchasing receivers and post processing software (1989-2010) area limitations was not even a topic. No caveat for ƒ??USƒ?? only, no issue with data or performance in China. No need to discuss in advance whether international or domestic.?ÿ

So, if unlimited area had to be specified and purchased thatƒ??s new to me.?ÿ