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Info
Note that the radar TCP server maintains state on the client connections therefore message start / stop requests, such as FFT Data, are applied on a per client basis.

Typically there are 2 3 types of payloads;payload:

Byte array representing a structure made up from standard C++ data types
Byte array representing a serialised Protocol Buffer message
Byte arrays that represent both of the above

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This is the first part of every message sent using this protocol. The header serves 2 purposes; : the first is to provide a byte sequence for synchronisation purposes; and secondly to provide information about the body of the message.

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Message Name	Message Id	Direction	Description
Configuration	10	From Radar	Sends all the radar configuration properties required to configure the client software to correctly receive data
Configuration Request	20	To Radar	Requests a configuration message from the radar
Start FFT Data	21	To Radar	Instructs the radar to start sending FFT data until told to stop
Stop FFT Data	22	To Radar	Instructs the radar to stop sending FFT data
Start Health Msgs	23	To Radar	Instructs the radar to start sending regular health messages until told to stop
Stop Health Msgs	24	To Radar	Instructs the radar to stop sending health messages
Reset RF Health	25	To Radar	Instructs the radar to reset RF Health check system
FFT Data	30	From Radar	An azimuth of raw radar data
High Precision FFT Data	31	From Radar	An azimuth of high precision radar data
Health	40	From Radar	Sends a radar health status message
Contour Update	50	To Radar	Enables the client to update the contour map on the radar
Sector Blanking Update	51	To Radar	Updates the blanking sectors on the radar
System Restart	76	To Radar	Request system reboot
Logging Levels	90	To/From Radar	A list of logging levels - v2 Hardware only
Logging Levels Request	100	To Radar	Request a list of logging levels - v2 Hardware only
Start Nav Data	120	To Radar	Request system to start sending navigation data
Stop Nav Data	121	To Radar	Request system to stop sending navigation data
Set Nav Threshold	122	To Radar	Set navigation threshold
Navigation Data	123	From Radar	Navigation data records
Set Nav Range Gain and Offset	124	To Radar	Set navigation threshold
Calibrate Accelerometer	125	To Radar	Radar will store current accelerometer value as flat
Start Accelerometer	126	To Radar	Start receiving accelerometer data
Stop Accelerometer	127	To Radar	Stop receiving accelerometer data
Accelerometer Data	128	From Radar	Accelerometer Data
Navigation Alarm Data	143	From Radar	SafeGuard Lite Alarms
Navigation Area Rules	144	To Radar	SafeGuard Lite Area Rules

Signature

The 16 byte signature differs very slightly from the older Navtech RMB protocol. This does enable existing software to differentiate between the two protocols if required.

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Navigation Configuration Request	203	To Radar	Request the current navigation configuration from the Radar
Navigation Configuration	204	From Radar	The current navigation configuration
Set Navigation Configuration	205	To Radar	Updates the Radar’s navigation configuration

Signature

The 16 byte signature differs very slightly from the older Navtech RMB protocol. This does enable existing software to differentiate between the two protocols if required.

The new signature is as follows:

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Field	Type [Size]	Description
Threshold	uint16_t [2]	Threshold to use for navigation data this . This should be a value between 0 - 96.5 dB multiplied by 10 e.g 75.6dB is 756

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Info

Azimuth to Bearing Algorithm

To convert from an azimuth to bearing you can use the following algorithm, utilising information from the configuration message:

Bearing = (Azimuth / Encoder Size) * 360 ie.eg. (2800 / 5600) * 360 = 180°

This bearing is relative to the Zero/North point of the radar, for CDR/CIR radars this is a line perpendicular to the flat part of the base:

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Log Levels Get/Set Messages

The log levels get and get set messages enable a user to get the logging levels and set the logging levels of the radar software. The LoggingLevelRequest message is an empty payload message, the radar will respond with a LoggingLevel message that contains a Protocol Buffer object which is a list of Log Levels. The get log levels payload is a Protocol Buffer serialised byte array. In order to de-serialise the message the client will need to use the Google library as described in reference: https://developers.google.com/protocol-buffers/.

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Code Block

public static class Utility
{
    public static uint SwapUInt32(uint value)
    {
        return (uint)((SwapUInt16((ushort)((value & 0x000ffff))) << 0x10)) | (SwapUInt16((ushort)((value >> 0x10) & 0xffff)));
    }
 
    public static ushort SwapUInt16(ushort value)
    {
        return (ushort)(((value & 0xff) << 8) | ((value >> 8) & 0xff));
    }
}
 
public class NavVector
{
    public NavVector() { }
 
    public NavVector(float x, float y)
    {
        X = x;
        Y = y;
    }
 
    public float X { get; set; }
    public float Y { get; set; }
 
    public byte[] ToBytes()
    {
        var x = (short)(X * 10.0f);
        var y = (short)(Y * 10.0f);
        var data = (uint)(x << 16) | (uint)y;
        return BitConverter.GetBytes(Utility.SwapUInt32(data));
    }
}
 
public class NavArea
{
    public NavArea()
    {
        Points = new List<NavVector>();
    }
 
    public List<NavVector> Points { get; set; }
 
    public byte[] ToBytes()
    {
        var data = new List<byte>();
        data.AddRange(BitConverter.GetBytes(Utility.SwapUInt16((ushort)Points.Count)));
        Points.ForEach(point => { data.AddRange(point.ToBytes()); });
        return data.ToArray();
    }
}
 
public class NavAreaRule
{
    public NavAreaRule()
    {
        Enabled = true;
        InvertBreakLogic = false;
        ThresholdDelta = 0.0f;
        BreakAllowance = 16;
        AllowanceCurveDecrement = 4;
        AreaToCheck = new NavArea();
    }
 
    public byte Id { get; set; }
    public bool Enabled { get; set; }
    public bool InvertBreakLogic { get; set; }
    public float ThresholdDelta { get; set; }
    public ushort BreakAllowance { get; set; }
    public ushort AllowanceCurveDecrement { get; set; }
    public NavArea AreaToCheck { get; set; }
 
    public byte[] ToBytes()
    {
        var ruleData = new List<byte> { Id, Enabled ? (byte)1 : (byte)0, InvertBreakLogic ? (byte)1 : (byte)0 };
        ruleData.AddRange(BitConverter.GetBytes(Utility.SwapUInt16((ushort)(ThresholdDelta * 10.0f))));
        ruleData.AddRange(BitConverter.GetBytes(Utility.SwapUInt16(BreakAllowance)));
        ruleData.AddRange(BitConverter.GetBytes(Utility.SwapUInt16(AllowanceCurveDecrement)));
        ruleData.AddRange(AreaToCheck.ToBytes());
        var data = new List<byte>();
        data.AddRange(BitConverter.GetBytes(Utility.SwapUInt32((uint)ruleData.Count)));
        data.AddRange(ruleData);
        return data.ToArray();
    }
}
 
public class NavUpdateAreaRules
{
    public NavUpdateAreaRules()
    {
        Rules = new List<NavAreaRule>();
    }
 
    public List<NavAreaRule> Rules { get; set; }
 
    public byte[] ToBytes()
    {
        var data = new List<byte> { (byte)Rules.Count };
        Rules.ForEach(rule => { data.AddRange(rule.ToBytes()); });
        return data.ToArray();
    }
}

Navigation Configuration Get/Set Messages

The Navigation Configuration Get/Get message set allow the client to request the current Navigation Configuration from the Radar, and provide an update to supersede the current configuration. A Navigation Configuration Request message is an empty payload message sent to the Radar, to which the Radar responds by sending a Navigation Configuration message. The client may sent an update of the Navigation Configuration parameters by sending a Set Navigation Configuration message.

The Navigation Configuration message is a fixed-structure message.

Navigation Configuration message structure

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Field	Type [Size]	Description
Bins to operate on	uint16_t [2]	Defines the search window in bins for peak detection.
Minimum bin	uint16_t [2]	The earliest bin for which peak detection will be enabled.
Navigation Threshold	uint32_t [4]	The threshold level for target detection. This should be a value between 0 - 96.5 dB multiplied by 10 e.g 75.6dB is 756
Max Peaks Per Azimuth	uint32_t [4]	The maximum number of detection peaks that will be reported. Once the maximum number of peaks have been detected, further peaks will be ignored.

Sector Blanking Message

A Sector Blanking message allows the client to update the set of blanking sectors for the Radar.

The payload for the message consists of a contiguous sequence of up to eight Blanking Sector structures. A Blanking Sector structure defines a start angle and finish angle for a blanking sector. The angles are stored as a pair of floating point values, as defined above. The first byte of the payload holds the number of Blanking Sectors to follow.

Sector Blanking Message Structure

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Field	Type [Size]	Description
Number of Sectors	uint8_t [1]	Specifies the size of the message payload, as a number of Blanking Sector structures. [0 .. 8]
Blanking Sectors	uint8_t [Payload Size - 1]	Up to 8 Blanking Sector structures, held as a sequence of bytes

Blanking Sector Structure

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Field	Type [Size]	Description
Start Angle	float [4]	The start angle of the sector [0 .. 360.0]
Finish Angle	float [4]	The end angle of the sector [0 .. 360.0]

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Version	Old Version 4	New Version 5
Changes made by	Benedict Dakin-Norris (Unlicensed)	Glennan Carnie
Saved on	Sept 15, 2021	Oct 01, 2021

Versions Compared

Key

Signature

Signature

Log Levels Get/Set Messages

Navigation Configuration Get/Set Messages

Navigation Configuration message structure

Sector Blanking Message

Sector Blanking Message Structure

Blanking Sector Structure

Related Information