in systems which transmit both gsm modulated and edge modulated signals , time of arrival estimations can be improved without requiring the detection of the type of modulation used on the received signal . in accordance with the present invention , a received signal is initially demodulated by a receiver in accordance with a first demodulation scheme . the demodulated signal is split into two copies . taking into account the initial demodulation , one of the copies is demodulated in accordance with another demodulation scheme , thereby resulting in a first signal demodulated in accordance with the first demodulation scheme and a second signal demodulated in accordance with a second demodulation scheme . a training sequence is used to correlate the two signals which are then summed in a incoherent integration process . the result of the incoherent integration is used to estimate the time of arrival of the received signal .