The relationship between exchange rate and trading

Between two countries, when one country (A) exports more to the other country (B) than importing from the other country, the currency of A will appreciate in terms of exchanging to the currency of B, as the demand of the A's currency increases. However, in reality, the exchange rate is purely determined by the expectation of trading rather than the true trading amount. Therefore, the exchange rate represents the trading positions of the two countries over the next decade, plus other factors which also determine the exchange rate. When we analyze the relationship between the exchange rate and the trade position, we could face lots of noise that causes the volatility of the exchange rate fluctuation. I think to minimize the effect of noise, we should analyze the relationship between the exchange rate difference and the trade position using the data on the day the trade data release.