Abstract: An object is to obtain a ground device capable of reducing a communication time of train information from an onboard device to the ground device. A ground device, which is capable of communicating with an onboard device and acquiring unreceived data from the onboard device by difference downloading or batch downloading, includes a difference-communication determiner to determine whether to acquire the unreceived data from the onboard device by difference downloading or to acquire all data to be acquired from the onboard device including the unreceived data by batch downloading. The difference-communication determiner includes a communication-time evaluator to evaluate a total communication time when data in a specified period is acquired by the batch downloading and that by the difference downloading, and a communication switch to output a download instruction based on a result of evaluation by the communication-time evaluator.

Abstract: An object is to obtain a ground device capable of reducing a communication time of train information from an onboard device to the ground device. A ground device, which is capable of communicating with an onboard device and acquiring unreceived data from the onboard device by difference downloading or batch downloading, includes a difference-communication determiner to determine whether to acquire the unreceived data from the onboard device by difference downloading or to acquire all data to be acquired from the onboard device including the unreceived data by batch downloading. The difference-communication determiner includes a communication-time evaluator to evaluate a total communication time when data in a specified period is acquired by the batch downloading and that by the difference downloading, and a communication switch to output a download instruction based on a result of evaluation by the communication-time evaluator.