NI position approximator

local iface = peripheral.wrap "back"
local x, y, z = gps.locate()

local approx = y
local function do_approx()
    local past_time = os.epoch "utc"
    while true do
        local time = os.epoch "utc"
        local diff = (time - past_time) / 1000
        past_time = time
        local meta = iface.getMetaByName "gollark"
        approx = approx + (meta.motionY * diff)
        sleep()
    end
end

local function do_gps()
    while true do
        local x, y, z = gps.locate()
        print("real=", y, "\napprox=", approx, "\ndiff=", y - approx)
        sleep(0.5)
    end
end

parallel.waitForAll(do_approx, do_gps)