No, you definitely are not. The LightSquared debacle unified the GNSS industry in a way that I had never seen before.
In fairness to FCC, that spectrum (adjacent to GPS L1) was supposed to be used for satellite, not terrestrial applications, in which case the danger to GPS devices (which, admittedly, often don't have the best filters) would have been minimal. The problem came when FCC granted LightSquared a waiver allowing them to use this spectrum for TERRESTRIAL services, where power levels would be substantially higher and pose a substantial risk of interference. After the FCC got a LOT of pushback from both the private and government/military sector, they rescinded the waiver until the potential interference issues were addressed (which they never were, and most likely never could be). The reborn version of LightSquared, Ligado, is trying to do the same thing again 8 years later.
Successfully spoofing GNSS signals (as opposed to getting a device to lock on a spoofed signal after a cold start) is really, really hard. The power level has to be just right -- too much power will also cause a GPS receiver not to lock. If you're spoofing from a single location, you have to very precisely calculate the path loss between your spoofed signal and the receiver, and this is obviously a problem when (a) you don't know where the receiver is and/or (b) there are multiple, non-colocated receivers you need to spoof. The advertised time has to be ahead of the last valid time: even very cheap GPS receivers will reject navigation messages "from the past" More sophisticated receivers / systems may reject any signals that are not coming "from the sky". This list of issues goes on and on. Something as simple as getting a freshly restarted device to lock on a simulated or "spoofed" constellation can also be problematic. Even in an indoor lab, a shield box is sometimes required. Getting a device that already has a lock to transition to a "spoofed" constellation is orders of magnitude harder. Oh, and all this only applies to the open L1 C/A code -- good luck spoofing the encrypted P(Y) or M codes
Believe it or not, there are people who want to introduce an updated version of LORAN-C (called "E-LORAN") as a backup to GPS. LORAN would be VERY difficult to jam. Every time I talk to the Coast Guard folks at GNSS trade shows I ask them about this and they just laugh at me
[End Quote above for emphasis] These are the sorts of comments that the folks involved in AIS were interested in. While no one has specifically mentioned 4G or 5G ( LTE ), the issue should be of concern to fellow amateur operators regarding APRS and to anyone holding an FCC General Radiotelephone License for obvious reasons- especially those with the Marine Radar Endorsement. My personal apologies for not getting specific about signal generators and failure to specify 'Jammers' compared to 'Spoofing' ( which I am sure can be either intentional or in very odd cases, unintentional ). Yet it is the 'unintentional' effects of the new allocations for 4G/ LTE / 5G ( any) types of L-band signals which at least 4 amateurs seem to care about. Not seeing any other theories for those 'circular tracks'- I think that the moderators could consider the 'thread' closed for now. The FCC may have sealed this in May, unless further action by Congress over-rides the decision. Thanks again to those who did comment, especially 4LZ and 6CLS.
I hope no one considers the thread closed or done, I'd like folks to post new updated and more specific info as it becomes available.
The reason that I was considering 'done' was because other than the latest replies, *Only KA0HCP* was good enough to comment on the theories that I expected might apply. If this were to be moved over to "News", rather than "General Announcements"- some folks might complain that it is not truly amateur radio. Yet the news of developments in the "Curious GPS interference" falls in three categories: 1. Reports of activities which might be classified as interference ( either intentional or by new sources ) to GPS reports through AIS ( or for that matter- any positioning system which generally works unless the antenna is shielded ). 2. Reports of the sources along with evidence given through official or independent observers. Note: the ARRL had/has a program of independent observers for amateur radio concerns. 3. Actions of groups approaching the F.C.C. and other authorities in the matters of frequency allocations in the GPS "L-band" /"Guard Band" range. Since #2 above includes the word evidence, it might be a much larger burden to provide- yet some of that is already found in the form of a table in the cited article. There are plenty of reports that the overall RFI/EMI 'noise floor' continues to increase worldwide, which is not what this 'thread' was supposed to be seeking- rather to explore what a few folks can monitor and report on. Maybe there is someone ( such as yourself ) that would care to 'restart this thread', given the same initial information. It seems safe to say that both the older ( non-crypto coded ) Global Positioning Systems in the L-Band and AIS systems in the VHF band are being intentionally interfered with. The real crux of the matter is whether or not there is something that we as amateur radio operators can do to preserve the GPS system as viable APRS reference. Since many are already providing weather reports and assisting public safety in 'parade' type events, I am certainly with K6CLS on preserving the thread- just not sure that someone else should 'restart' it , given what has been said about AIS having been 'hacked' or 'spoofed'.
As requested: https://www.gpsworld.com/year-long-ocean-cruise-finds-gnss-interference-everywhere/ ( Related to efforts 2 years ago, not the specific 'circling', yet related positioning interference info ) and https://www.gpsworld.com/fcc-grants-e911-galileo-request-to-att/ ( Pertains to cellular location and other than USA GPS systems for location accuracy ) and https://www.gpsworld.com/u-blox-technology-platforms-support-beidou-3/ ( Pertains to one other positioning system- not the same as USA GPS, same purpose - vendor ) and https://www.gpsworld.com/white-house-office-asks-what-to-research-to-protect-gps/ ( No comment here- reminder- we try to stay neutral on politics.... ) Go for it ( feel free to keep posting... ). Or start again...
I have locked a private discussion group on this subject for cause ( no way to drop a single member who did not want additional information ). Please let me know if any of you know of funding regarding that last link. There should be a way to use the pre-existing GPS (the U.S. based one, not Beidou, Glonass, Magellan, etc.) system in a way that affords more immunity to interference. Since surveyors also use land stations for D.G.P.S., why not see about adding additional reference stations and better dual-frequency receivers for all authorized users? Cost.
Today's report on Fox26 regarding hidden prisons and COVID-19 C/O Marie Baritromo(sp) could get things started... There is a time for everything.... (plagerism from Ecclesiastes). Be careful what you wish for. They seldom call us 'old fossils' back in the first 'draft'. Numbers 6, 24-26.
Hi Jon, I was intrigued by the discussion group. I thought you chose a good bunch of fellows. I looked forward to some thoughtful. informative responses, and a vigorous discussion. The one who didn't want more info has repeatedly demonstrated he is immune to facts and logic. Curiously for someone with a post graduate degree, also seems to be unwilling or unable to read. For your part, when posting ... paragraphs are your friend. Put blank lines between each idea. Much easier to read. Many people are defeated by the "wall of text" and don't even try. OK back on topic .... it's good to document GPS interference., seems to occur much more frequently these days. More coinstellations won't help (GLONASS, Galileo, Baidu). I like the idea of reviving LORAN, especially e-LORAN. It was very short sighted to dismantle the transmitting sites. That cost the USCG more than several years of operation al costs. $0.01 wise, $1.00 foolish.
The irony of that last one: https://www.gpsworld.com/white-house-office-asks-what-to-research-to-protect-gps/ And then I noted the spelling of Baidu. If I am not mistaken, that goes with an actress/singer name: Erika Baidu or similar. As we draw near to 'All Hallowed Eve', I remember her in some haunting roles. That too ( re: Beidou Positioning, sponsor country ) and politics might be ironic. Many may fail to see that connection, because the history goes back...
The name that I thought K6CLS was using for Beidou would be Erykah Badu*. Prior to various awards, she acted in certain movies Which might make folks believe in the occult. In truth, no one is without sin- and that was some pretty good acting- though the reviews were mixed. Name changed from Erica... of course! Getting back to the subject at hand, the first post here ( interference ) had a second link ( FCC actions ) which also borders on the political. The testimony reported/reporting is the ironic part.
