Because all objects are affected by gravity, we can't actually measure a "gravitational field" in the same sense that we can measure , say, an electric field. In some specialized circumstances we can work around this lack of a reference particle that would be "unaffected by gravity", but the case of a moving mass isn't one of those special circumstances.
What we could measure, in principle, is the tidal gravitational field of a moving particle - the accelerations induced in nearby test particles relative to each other. Unfortunately, the detailed presentation on it gets rather technical. It's known as the Aichelburg - Sexyl solution, and in general terms, it looks like a plane wave, similar to the electromagnetic case, which behaves in a similar manner.