Distance measurement

A method comprising:

• determining a total delay error that when added to a reference time equivalent to a reference distance between a first antenna and a second antenna equals a difference between a transmission time of a signal sent via the first antenna and a reception time of the signal received via the second antenna;
• measuring a frequency-variable first delay associated with reflection of a transmitted signal by a frequency-variable complex impedance of the first antenna;
• measuring a frequency-variable second delay associated with reflection of a transmitted signal by a frequency-variable complex impedance of the second antenna;
• estimating a first portion of the total delay error associated with the first antenna in dependence upon at least the first delay;
• estimating a second portion of the total delay error associated with the second antenna in dependence upon at least the second delay;
• and
• adjusting, at a user equipment, a transmission timing and a reception timing based on the first portion of the total delay error and the second portion of the total delay error.

A non-transitory computer-readable storage medium storing a computer program comprising instructions that when run on one or more processors enables:

• determining a total delay error that when added to a reference time equivalent to a reference distance between a first antenna and a second antenna equals a difference between a transmission time of a signal sent via the first antenna and a reception time of the signal received via the second antenna;
• measuring a frequency-variable first delay associated with reflection of a transmitted signal by a frequency-variable complex impedance of the first antenna;
• measuring a frequency-variable second delay associated with reflection of a transmitted signal by a frequency-variable complex impedance of the second antenna;
• estimating a first portion of the total delay error associated with the first antenna in dependence upon at least the first delay;
• estimating a second portion of the total delay error associated with the second antenna in dependence upon at least the second delay;
• and
• adjusting, at a user equipment, a transmission timing and a reception timing based on the first portion of the total delay error and the second portion of the total delay error.