Abstract:

We provide a scheme for verifying satellite locations, where the locations are reported by satellites themselves. In the scheme, satellites periodically report their locations to the network and these are included in a list. The locations are occasionally verified through a type of proof-of-location protocol. A proof of location is provided via the solution to a cryptographic puzzle and adherence to geometric constraints. The cryptographic puzzle is constructed as a layered data packet, where each layer can be removed only by a specific satellite. This by itself ensures that the challenge was completed in the requisite order. As part of the response to the challenge, each satellite reports its position and time. These reports are verified against the physical constraints of the speed of light and radio signal strength decay.
The scheme secures location reports and proofs of location using a permissioned blockchain. Having a source of truth allows locations to be verified retrospectively, which is important due to asynchronous communication between satellites. Satellite reports can arrive out of order and updating past observations with more reliable information is essential to achieving consensus on the veracity of location reports. Although location verification could be implemented as a centralized scheme, decentralization enables scalability and trustless cooperation between satellite operators, potentially reducing costs in deployment and operation of satellite constellation.