A system for accurately measuring fluid level in a vessel, comprising: an elongated portion being a coaxial waveguide having a first conductive outer shell that is hollow except for a coaxial inner conductor; an arm being a coaxial waveguide comprising a second conductive outer shell, the arm being filled with a solid dielectric which yields a known impedance at conditions under which the fluid level is being measured; and a sensor comprising a transmitter capable of creating and transmitting an excitation electromagnetic pulse for traversing the elongated portion and the arm, and a receiver for receiving reflected pulses, the sensor further comprising power supply circuitry, digital logic, and analog circuitry; wherein a proximate end of the elongated portion physically joins a distal end of the arm in a manner to create a continuous waveguide comprising the arm and the elongate portion for an electromagnetic pulse provided by the sensor; and wherein the digital logic further comprises a processor, wherein the processor further comprises: logic configured to initiate the transmitter for sending the excitation electromagnetic pulse; logic configured to synchronize the receiver to the excitation electromagnetic pulse; and logic configured to determine temperature of the fluid by measuring actual dielectric constant of the fluid and comparing the measured actual dielectric constant of the fluid to a list of fluids having known dielectric constant values. an elongated portion being a coaxial waveguide having a first conductive outer shell that is hollow except for a coaxial inner conductor; an arm being a coaxial waveguide comprising a second conductive outer shell, the arm being filled with a solid dielectric which yields a known impedance at conditions under which the fluid level is being measured; and a sensor comprising a transmitter capable of creating and transmitting an excitation electromagnetic pulse for traversing the elongated portion and the arm, and a receiver for receiving reflected pulses, the sensor further comprising power supply circuitry, digital logic, and analog circuitry; wherein a proximate end of the elongated portion physically joins a distal end of the arm in a manner to create a continuous waveguide comprising the arm and the elongate portion for an electromagnetic pulse provided by the sensor; and wherein the digital logic further comprises a processor, wherein the processor further comprises: logic configured to initiate the transmitter for sending the excitation electromagnetic pulse; logic configured to synchronize the receiver to the excitation electromagnetic pulse; and logic configured to determine temperature of the fluid by measuring actual dielectric constant of the fluid and comparing the measured actual dielectric constant of the fluid to a list of fluids having known dielectric constant values. logic configured to initiate the transmitter for sending the excitation electromagnetic pulse; logic configured to synchronize the receiver to the excitation electromagnetic pulse; and logic configured to determine temperature of the fluid by measuring actual dielectric constant of the fluid and comparing the measured actual dielectric constant of the fluid to a list of fluids having known dielectric constant values.