If I were to try to copy that, I would look for a pattern for a basic jewel neck cardigan with set in sleeves for the stitch count and armhole shaping. Done in the 2x2 rib, it will be more close fitting. For the split front lower edge, beginning at the bottom knit the left and right separately, then join and work the whole front, dividing again for the v neckline.. I don't think that v neck shaping is needed, because the collar will spread the neckline.
The shape of the collar is just a rectangle, about 4 inches deep. It could be either made as a separate piece and sewn on, or picked up after the front and back is sewn together. A row or two of fine crochet in slip stitch, single crochet or crab stitch around the armholes and neckline would stabilize the rib stitch.