What: Shares of Trimble Navigation Limited (NASDAQ:TRMB) were up 20% as of 11:30 a.m. Friday after the company announced mixed third-quarter 2015 results.

So what: Quarterly revenue fell 4% year over year to $562.3 million (but would have been flat excluding the negative effect of foreign currencies), including a 5% decline in Engineering and Construction revenue to $326.4 million, a 17% decline in Field Solutions sales, a 9% increase in Mobile Solutions revenue, and a 6% decline from Advanced Devices. That translated to an 11% decline in adjusted net income to $77.8 million, and a 9.1% decrease in adjusted net income per share to $0.30.

That might not sound impressive, but both the top and bottom lines were well above Trimble's own guidance, which called for revenue between $535 million and $560 million, and adjusted earnings per share of $0.19 to $0.26. Similarly, analysts' consensus estimates predicted significantly lower adjusted earnings of $0.23 per share, and revenue of just $545.9 million.

Trimble CEO Steven Berglund acknowledged his company's challenges, but also offered a light at the end of the tunnel, stating "Revenue was negatively affected by continued poor conditions in the agriculture market, the effects of oil price declines, and foreign exchange effects. As these conditions lessen we anticipate a return to growth in 2016."

Now what: Looking forward, Trimble expects current-quarter revenue between $520 million and $550 million, and adjusted earnings per share of $0.19 to $0.26. Analysts were more optimistic, with estimates calling for Q4 revenue of $557.4 million, and earnings of $0.25 per share.

Keeping in mind Trimble just effectively under-promised and over-delivered in Q3, it's no surprise the market isn't paying much attention to its possibly conservative guidance this time. For now, I'm content continuing to watch Trimble from the sidelines in its efforts to return to sustained growth in the coming year. But I also can't blame investors for bidding up Trimble stock today.