I want to compute the derivatives of argument of periapsis and longitude of the ascending node of the orbit of a GPS satellite from the following formula.
$$\frac{d\Omega}{dt} = -K \cos{i} \\ \frac{d\omega}{dt} = K ( 2 - 2.5 \sin^2{i}) \\ K = \frac{nK_1}{a^2(1-e^2)^2}$$
But what is $K_1$?