FOAM Update: Trust Zone Announcement

FOAM is a low cost, open source radio protocol made for blockchain applications needing verified location services. Our team is committed to building new forms of Presence Claims that offer a high level of security and resiliency, offering new solutions over conventional geospatial technologies. Proof of Location is a critical prerequisite for the further development of Web3 use cases, accelerating a world where smart contracts interact with the physical world.

Zone Anchor Product Concept Render
Zone Anchor Product Concept Render


It is an exciting year ahead for FOAM, which the Foamspace team has remained hard at work on. This post is meant to serve as an update as well as a general introduction to the project for those newly joining us. The FOAM protocol is a radio based network of zones to provide location services for Web3 applications - that operate independent of GPS. After a period of research and development, this post also marks a new phase of the protocol with the launch of the Trust Zone program described further below.

At FOAM we are developing unprecedented use cases that were previously not possible using existing networks. Say that you want to send a Web3 transaction that uses the physical location of your transmitter to interact with a smart contract, to mint an NFT or unlock a delivery payment for example. FOAM enables the location data to be externally verifiable and provably correct, within parameters that are given for each transaction before transmitted. Currently, these types of applications are vulnerable to spoofing and jamming but can be enabled with a decentralized deployment of FOAM Zone Anchors around the world.

Thus, the fundamental problem that FOAM addresses are critical infrastructure vulnerabilities in GPS, exposed and exploited from Uber drivers and Pokemon Go players to nation state actors and attackers on new emerging wireless networks in the form of spoofing and jamming signals (NYT: America Has a GPS Problem). After governmental calls and reviews of existing technology to serve as a back up to GPS, it has been seen that there is no one size solution to the system and a new ecosystem of Positioning, Navigation and Timing services is needed to complement and or work independently:

The position and navigation functions in critical infrastructure are so diverse that no single PNT system, including GPS, can fulfill all user requirements and applications. Because of this, DHS could not identify generic specifications for a national backup. Position and navigation backups must be application-specific and must be developed in coordination with industry owners and operators. -Department of Homeland Security

FOAM will be a part of this emerging ecosystem and service applications that require fraud proof location claims and interoperability with smart contracts and provide a protocol that is “invaluable and unstoppable public infrastructure”.

Presence Claim

FOAM is a protocol made of Zones of coverage provided by radios called Zone Anchors. Each Zone requires a minimum of four Zone Anchors to form a Zone of coverage. Zones maintain a quorum on time and space in their local and Zone operators will stake FOAM into service level agreements to guarantee up time and reliability. Presence Claims are what end users of the FOAM protocol can generate as a proof of their location, by interacting with the Zone over radio with cryptographic signatures, unlike GPS which is a passive one way system.

A Presence Claim can only be generated by a user if they are physically within the Zone they claim to be in. Presence Claims are a new primitive that can be consumed by smart contract applications. Applications that can utilize such a primitive ranges from retail, insurance, transportation, supply chain, gaming to file storage.

Any FOAM transmission wraps any data with one or more of the following:

1. Cryptographic signature
2. Web3 transaction
3. Presence Claim    

Zone Anchor’s witnessing a location claim requested by a user within the Zone all sign this message to produce a presence claim, and can, in contrast to GPS data, be used as a “proof of location”. This is because it was generated in a transparent, auditable system in which every Zone Anchor is participating through a staked entry. It is thus possible to inspect a presence claim and exactly calculate how reliable it is. Zones provide a hybrid, fault tolerant and distributed radar.


The purpose of the FOAM radio network is to facilitate verifiable transmissions using cryptographic signatures, blockchain transactions and Presence Claims. For this to work there are a number of hardware, software, and network solutions that the FOAM team has developed.

Our nodes, called Zone Anchors, transmit to each other over LoRa with sample-accurate timing logs that securely localize the transmission sources. Four or more Zone Anchors form a Zone. Not only can they localize each other within that Zone, but crucially, also have the ability to localize any other LoRa node that enters the Zone. Zone Anchors leverage a custom hardware design utilizing FPGA facilitating low-energy and high speed signal processing, that would otherwise be impossible using a traditional architecture. It also allows us to commit to an Open Hardware design, as outlined in previous posts.

Hostel: Application for managing experiments and viewing results
Hostel: Application for managing experiments and viewing results

For the past 18 months we have maintained and operated our own Zone in the Brooklyn Navy Yard, regularly running automatic, on-the-ground tests to iterate on our localization algorithms. Along side this effort, we have developed a suite of tools for: remotely configuring radios and the Zone, executing and monitoring experiments, data pipelines for processing localization data and dashboards for quality assessment and visualizations. A web app called Hostel has been developed for managing experiments, localization results and the health of a zone.

Recent development milestones have been the real time streaming of processed localization, comparable to GPS in accuracy and latency. Additionally, the Zone is now continuously available and listening for users, akin to how the network would operate in real world conditions, a move away from purely experiment conditions.

Current Prototype Zone Anchor Radios
Current Prototype Zone Anchor Radios

In the FOAM Zone, the provenance of the location data differs from that of a self-reporting GPS receiver. Rather, it is localized by a distributed trust-less network of devices that continuously verify each other’s location. The network effectively acts as a hybrid, distributed radar.

Localization and Radio Packet Analysis Dashboards
Localization and Radio Packet Analysis Dashboards

Until now, we’ve been running these experiments in a closed network. We are excited to announce that it is now time to open up this experiment by adding community run Zones!

Trust Zone Program

The goal of the Trust Zone program is to have select partners run the FOAM protocol in different geographical environments and test different zone configurations. The selected participant partners will also assemble the current prototype of the Zone Anchor, secure a minimum of four roof locations for installation, run localization experiments and submit the results for evaluation.

This is a beta testing program for early qualified stakeholders aligned with the mission of the protocol to contribute to refining and defining needed features. The partner participation process will be to maintain your own Zone with a focus on building a high quality fault tolerant network that will seed the network’s initial growth and security.

Zone Anchors can be tested on Stands before a permanent installation
Zone Anchors can be tested on Stands before a permanent installation

The program will be conducted in two phases. In Phase 1, a limited number of teams will work to replicate our Brooklyn Navy Yard Zone with the same prototype equipment and experiment tools and contribute directly to the further development of the protocol. Phase 2 will expand the number of eligible participants with added cryptographic features and include the option of running a Zone Anchor v1 product radio. Our next post will detail the requirements for participation and application process.

Zone Anchor Product

In parallel to the exciting developments described above, we have been designing a FOAM radio with a customRF board containing the necessary components for a Zone Anchor to be manufactured and operate under industrial conditions. This new unit offers remarkable improvements in reduced size and capabilities based on our our own custom hardware design experience.

We were able to manufacture the first revision of our custom radio PCBs in the beginning of this year and will very soon be moving towards production of a small batch run. We will share more information about the production schedules as we go along. Even though we were affected by the supply chain issues like the rest of the industry, we were able to mitigate any risks by early procurement and proactive hardware design.

Brackets for Mounting on a Roof parapet
Brackets for Mounting on a Roof parapet

Expanding FOAM

In addition to the above, we are also excited to now offer the much anticipated FOAM Lite developer tools and documentation, showcased at ETHDenver that as available for development today. It could be said that with FOAM Lite, signatures and web3 transactions are enabled for sensors, whereas with the Trust Zone program the focus is on decentralizing the generation of Presence Claims for location.

As the Trust Zone Program expands it will merge with incentivization of participation in the network through staked signals as NFTs since 2018 on the Ethereum mainnet and updates to existing map contracts. The complete vision of the FOAM network is starting to come together. This year will be full of FOAM developments in this area, stay tuned.

One of our top priorities in the short term is to expand the FOAM team, with special attention to a Technical Project Manager for user onboarding and coordinating the Trust Program and a Community Manager for additional initiatives. If interested please email and check back here for expanded job postings.

FOAM Signal NFTs
FOAM Signal NFTs
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