The JPL planetary ephemerides are saved as files of Chebyshev polynomials fit to the Cartesian positions and velocities of the planets, Sun, and Moon, typically in 32-day intervals. The positions are integrated in astronomical units (au), but with polynomials stored in units of kilometers.
JPL planetary and lunar ephemerides DE436 integrated 30 September 2016. DE436 is based on DE430 documented in JPL Interplanetary Network Progress Report 42-196 http://ipnpr.jpl.nasa.gov/progress_report/42-196/196C.pdf, 15 February 2014. DE436 is specifically an update of the ephemeris of Jupiter for use by the Juno project navigation team. Time span covered by the full ephemeris de436.bsp is:
1549-DEC-21 00:00 to 2650-JAN-25 00:00
JD 2287184.50 to JD 2688976.50