Raymarine EV-1 Sensor Core - 9-Axis Heading Sensor + Autopilot CPU

The Raymarine EV-1 Sensor Core is the central sensor and processor for every Raymarine Evolution autopilot system - the heading sensor, motion sensor, and autopilot CPU all in one sealed housing. For owners adding an EV-1 to an Evolution autopilot system (either replacing a failed unit or building out a new system component-by-component instead of buying a complete pack), the standalone EV-1 is the right part.

What 'EV-1 Sensor Core' actually is. The EV-1 combines two functions that were separate components in older autopilot systems: the heading sensor (the compass / motion sensor that tells the autopilot which way the boat is pointed) and the autopilot processor (the CPU that runs the steering algorithms and decides how much steering correction to apply). In older Raymarine systems (and most other autopilot brands), these were separate components - a fluxgate compass mounted somewhere on the boat, plus an autopilot processor mounted somewhere else. The EV-1 integration puts both functions in one housing - simpler install (one component instead of two), better data integrity (the sensor and processor are physically next to each other, no signal degradation in cabling between them), and tighter system tuning (the integrated design is optimized as a unit rather than mixing components from different generations).

9-axis sensor design - what it provides. The EV-1 uses three sensor types combined: (1) 3-axis digital accelerometer - measures linear acceleration in three axes (forward / back, port / starboard, up / down), used to detect boat tilt (pitch and roll angles) and dynamic motion. (2) 3-axis digital compass / magnetometer - measures the earth's magnetic field in three axes, used to calculate magnetic heading. (3) 3-axis digital gyro angular rate sensor - measures rotational rate around three axes, used to detect heading change rate (how fast the boat is turning). Combined 9-axis data gives the autopilot a complete picture of vessel motion - far more than older 2-axis or 3-axis sensors that gave only compass heading or basic compass plus tilt. The richer sensor data is what enables Evolution's tight heading hold and smooth course corrections that older autopilots couldn't match.

Dynamic accuracy to within 2 degrees. The combined sensor performance delivers heading accuracy within +/- 2 degrees under dynamic conditions - meaning even when the boat is rolling in waves, accelerating, or turning, the heading data stays accurate. Static accuracy (boat at rest) is significantly better. The 2-degree dynamic accuracy is what enables precise autopilot control - lower-accuracy sensors lead to autopilot 'hunting' (constant overcorrection because the heading data is noisy or inaccurate).

Auto-compensation for magnetic fields. The EV-1 automatically compensates for the onboard magnetic field interference that's normally a major problem for marine compasses (interference from steel engine blocks, electronics, wiring, speakers, anchors, and any other ferrous material on the boat). Older marine compasses required a manual 'compass swing' procedure - sailing the boat in circles to specific headings and adjusting compensator magnets to dial out the boat's specific magnetic interference. The EV-1's auto-compensation eliminates this multi-hour procedure - just install and use, the sensor figures out the boat's magnetic signature during normal operation.

Northern and southern extreme handling. At high latitudes (far north or south), the earth's magnetic field tilts steeply down (magnetic dip), making traditional fluxgate compasses unreliable. The EV-1's 9-axis sensor design handles magnetic dip mathematically - the gyro and accelerometer data compensate for the tilted magnetic field, maintaining accurate heading even in arctic and antarctic operations. Important for offshore passages crossing into high-latitude waters, less important for typical coastal cruising in temperate latitudes.

MARPA and radar overlay support. Beyond autopilot use, the EV-1's heading data is critical for MARPA (Mini Automatic Radar Plotting Aid) target tracking on Raymarine radar - MARPA needs reliable heading data to calculate target courses and CPA (Closest Point of Approach). Radar overlay on the chartplotter also requires heading data to align the radar image with the chart orientation. The EV-1 provides both - one sensor source feeding the autopilot, MARPA, and radar overlay simultaneously.

SeaTalk NG single-cable connection. The EV-1 connects to the Evolution autopilot ACU (Actuator Control Unit) and other Raymarine network components via SeaTalk NG - the Raymarine network protocol based on NMEA 2000 with Raymarine-specific connectors. Single-cable design carries both power and data, simplifying installation vs older autopilot sensors that required separate power and data cables. For installations integrating with NMEA 2000 networks, the EV-1 data is also accessible to any NMEA 2000-compatible device on the network via standard NMEA 2000 messages.

IPX6 / IPX7 waterproof - mount anywhere. The sealed enclosure is rated IPX6 (protected against powerful water jets) and IPX7 (protected against temporary submersion in 1 meter of water for 30 minutes). Mount the EV-1 above deck (exposed location like a mast bracket or open deck) or below deck (cabin, lazarette, electronics compartment) - the waterproofing handles either environment. For best autopilot performance, below-deck mounting is typically preferred (away from temperature extremes and direct UV exposure that can affect long-term electronics life).

Compact dimensions and low weight. The housing is 5.5 inches in diameter and just 1.4 inches deep (3.8 inches including the wall mounting bracket). Weight is just 0.64 lbs - light enough to mount on a vertical bulkhead with the included mounting tray and standard hardware without requiring structural reinforcement.

What's in the box. Complete kit: EV-1 heading sensor / autopilot CPU in sealed housing, 1-meter SeaTalk NG spur cable (for connecting to the network backbone), document pack with installation instructions, mounting tray (the wall bracket that holds the sensor), and mounting hardware (screws / bolts for typical installations). Compatible with all Raymarine Evolution mechanical and hydraulic autopilot Actuator Control Units (ACU-100, ACU-150, ACU-200, ACU-300, ACU-400) - the EV-1 is the universal sensor for the entire Evolution autopilot lineup.

Install considerations. The EV-1 mounting location is critical for proper autopilot performance: (1) AWAY from magnetic interference - keep at least 3 feet from large iron / steel objects (engine blocks, big speakers, large wiring runs, other magnetic compasses, large fuel tanks). (2) AWAY from strong vibration - mount on a stable bulkhead rather than a vibrating engine cover or thin paneling. (3) Aligned with the boat's centerline - the sensor has a clearly marked forward arrow that must point toward the bow. Even a few degrees of misalignment causes constant heading offset. (4) Level if possible - while the sensor compensates for vessel motion, starting with a level mounting orientation gives best dynamic accuracy. Plan the location carefully before drilling - relocating after install means re-doing the auto-calibration learning process.

The auto-learning calibration. After install, the EV-1 self-learns its position and the boat's magnetic signature during normal operation. Take the boat out and operate normally - within a few hours, the auto-calibration completes and the autopilot achieves its full accuracy. Unlike older heading sensors that required dock-side calibration procedures and on-water compass swing maneuvers, the EV-1 just learns automatically during the first hours of use.