Calibration of a level gauge system

摘要

A method of calibrating a level gauge system using electromagnetic signals to determine a filling level of a product in a tank. The level gauge system comprises a real time sampler for sampling a reflection signal with a sampling period between consecutive samples. The method comprises the steps of: receiving timing signals from a wireless communication network; generating time stamp signals based on the timing signals; registering a number of the sampling periods between a first time stamp signal and a second time stamp signal; and determining the sampling period based on the registered number of sampling periods and a time between the first time stamp signal and the second time stamp signal. Various embodiments of the present invention provide for high accurate determination of the filling level in a tank without the need for a temperature stable and highly accurate clock reference in the level gauge system.

主权项

1. A level gauge system, for determination of a filling level of a product in a tank using electromagnetic signals, said level gauge system comprising:
a signal propagation device, for transmitting a pulsed measuring signal into the tank, and receiving a reflection signal from the tank; a transceiver module having a pulse generator for providing said pulsed measuring signal to the signal propagation device, and a real time sampler for sampling said reflection signal with a sampling period between consecutive samples to provide a sampled reflection signal; processing circuitry, connected to receive said sampled reflection signal from the transceiver module and configured to determine said filling level based on said sampled reflection signal and said sampling period; and a wireless communication device connected to said processing circuitry for providing a wireless communication signal indicative of said filling level to a remote location via a wireless communication network, said wireless communication device being configured to receive timing signals via said wireless communication network and to provide timing information based on said timing signals, wherein said level gauge system further comprises calibration circuitry arranged to receive time stamp signals being based on said timing information, and configured to register a number of sampling periods between a first time stamp signal and a second time stamp signal, and wherein said processing circuitry is further configured to estimate said sampling period of said real time sampler based on the time between the first time stamp signal and the second time stamp signal, and said number of sampling periods registered by said calibration circuitry.