The FCC plans to hold a vote in April to consider alternatives to GPS, the U.S. location technology. The aviation industry has reported an increase in GPS spoofing, where a fake GPS signal shows a pilot the wrong location of a plane. GPS spoofing has been common around conflict zones, but airlines are reporting it happening in other places.
There are national security concerns because GPS is now used extensively by airlines, shipping, the military, and by the public for a wide range of uses. There is growing fear of the negative impact of something going wrong with GPS due to malicious attacks, technical malfunctions, or natural phenomenon like solar flares.
GPS technology was developed by the U.S. and is currently controlled by the U.S. Space Force. The technology was first designed in 1973 and became fully functional when a constellation of 24 satellites was in place in 1993. The U.S. government first made GPS available for civilian uses after Korean Air Lines Flight 007 was shot down in 1983 when it entered Russian air space. Over time, the government allowed wider use of GPS, and the technology is familiar to everybody who uses it as the basis for driving directions.
We’ve already begun to modernize the GPS network. There are currently 18 new GPS satellites in orbit that use the L5 frequency band that can provide accuracy for functions like surveying within 2 centimeters. The new satellite constellation will be completed in 2024 when it reaches 24 satellites.
GPS is not the only location network in the world. Russia has a GLONASS network, China a BeiDou network, and the European Union operates its Galileo locating network.
The purpose of GPS is supply geolocation information and the time anywhere on earth. Folks in the telecom business are familiar with GPS because we use it to mark the location of network outdoor components. GPS can help to lead a technician directly to the source of a network problem.
The FCC wants to open an exploration into other locating technologies so that we aren’t dependent on the GPS satellites. There are alternatives to GPS that can be explored, and it seems likely that a second locating system would be used in conjunction with GPS so that there wouldn’t be a single network providing the service. Some of the alternate technologies that might be considered include:
- GNSS (Global Navigation Satellite System). LORAN (Long Range Navigation) technology is already used in conjunction with current GPS. This is a land-based network that use low-frequency radios that allow a calculation of position. Today LORAN supplements GPS in areas where reception is poor, and it can enhance accuracy where GPS is being used. Some are proposing that an updated eLORAN network be built as more extensive alternative to GPS. The downside is the cost of build a large numbers of LORAN towers around the world.
- INS (Inertial Navigation System) is a self-contained system that keeps track of the location of an INS device through continuous motion tracking – the device constantly calculates where it is at. The technology is already used today in airplanes, ships, and by the military. The devices are fairly expensive but could become more affordable with mass production. The downside is what is called sensor drift where a device has to occasionally be recalibrated by connecting to GPS or another location system.
- Quantum Clocks are still in the research and development phase but hold promise for timekeeping and location calculations. Quantum clocks are far more accurate than the atomic clock that is currently used as our time standard. The lab devices today are complex, and the challenge to make this into a usable technology is miniaturization and mass production.
NextNav, Inc (nextnav.com) holds a license for a portion of the 33 CM band that, if exercised will eliminate most of the 902-928 MHz ISM band. This will impact utility companies, developing IOT devices such as LORA/Meshtastic, telemetry for drones and other robotics, and amateur radio. The FCC will be making a decision over the next few months. IMHO this is not a good development and largely unnecessary. Read more about the proposed reallocation here: https://www.zeroretries.org/p/zero-retries-0193?open=false#§the-threat-to-the-us-mhz-cm-band-from-nextnav
When talking cost, keep in mind that the GPS system is REALLY expensive.
Also note that faking GPS isn’t GPS’ fault, it’s the reporting that’s flawed. ie, you don’t lie to the GPS satellites, you lie in your transponder.
So long as the transponder reports it’s location, it can lie. It can be hacked. adding a second location methodology doesn’t change this. you can try to crytographically secure it, but those things can be hacked and the hackers get to work ‘live’ while the system basically has to work in version levels and distributed updates and all sorts of slow methods.
I think what’s critically required is transponder listeners, which could be space based or land based or a combo. When a transponder sends, that signal can be computed from receive time and high accuracy clocks to sanity check. Basically inverted GPS. This would be increadibly hard to fake with a single aircraft and even if a swarm of aircraft were in play to spoof location the location of each broadcaster could be identified with relative certainty. Then the included GPS coordinates are ‘backup data’.
I personally experienced the utilization of military-grade forward scrambling technology, collecting GIS data for a Tribal power utility company, while working nearby a military aircraft training area. I had previously read an article in a RF & microwave publication. Before I arrived on the “all hands-on deck” project, several of our field collectors had been experiencing loss of survey-grade accuracy in open country. They had been rebooting their equipment as a result to resolve the issue, but the effects didn’t typically resolve with a restart. I explained the technology as revealed in the publication. About a week later, I had the experience personally, with GIS accuracy going from 10cm lock out to 100 meters plus. I waited approximately 1~2min, before spotting three A-10’s at about 300′, banking over my remote location, to see what I was doing in the middle of the Sonoran Desert.
Conformation.
As soon as they cleared the area, GIS sync & lock accuracy completely restored.
I haven’t had opportunity to test if RTK would potentially provide a maintainable signal in this scenario, but I doubt it would.
I don’t believe RTK would help, you receive offsets for higher resolutions from RTK. What’s a 77cm 0 azimuth adjustment going to do for a 100 meter locate :/
My post above was more about how air traffic could handle it. Publically available locating needs some other solution that doesn’t collapse when a government decides.
The helium network offers up a pretty reasonable solution in a lot of areas, LoRaWAN beacons can get you reasonably accurate and I think you could retrofit RTK into that also…