The American outfit sealed its best-ever result in Formula 1 last year by claiming P5 in the Constructors’ Championship, continuing its year-on-year improvements.
Speaking via Crash.net, Magnussen said: “If you look at our trajectory since the beginning of the team it’s just been forward.
“Last year we took a big step from 2017 to 2018. I don’t think we can expect to take as big a step again but we can expect to keep improving and stay on the rise.
“I really don’t expect us to take a step back, I think we’re going to continue to grow. But we need to improve, and we need to grow even to hold onto fifth.
“Probably this year the improvements and the step forward will be less visible most likely, but I can see how we are growing as a team and we are gaining more and more experience.
“We’re learning with that experience that we’re gaining also to make use of that experience. I’m positive.”
Magnussen’s team-mate Romain Grosjean declared he is targeting P4 in the Constructors’ Championship, after missing out by only 29 points in 2018.
“I think you always want to do better and last year was a big step for us from the first two years,” he explained.
“But we weren’t miles away from fourth so I believe that we want to be better and therefore fourth is the next target.
“We can talk about even being World Champions but first we need to see how the car is going and then really decide where we can go.
“Last few years the car has been good at the beginning and we have improved the team since day one.
“I’m very proud of the work we have been doing and the growth of the team. It’s been a big journey and I don’t think it’s over yet.”