satcat5::ptp::DopplerTlv Class Reference

Detailed Description

TlvHandler for experimental Doppler-TLV tags.

Ordinary PTP assumes all nodes are stationary, the path length is fixed, and delays in each direction are symmetric. Violating these assumptions results in biased or inaccurate time transfer. This class defines experimental extensions that relax these assumptions, allowing motion to be measured and mitigated for better accuracy.

The largest change is the creation of a new TLV for Doppler metadata. This file implements the software that initializes and read such tags at each endpoint. Transparent clocks that support Doppler-TLV require gateware or hardware that increments the tag's contents at each hop. TlvHandler for the Doppler-TLV tags.

Definition at line 28 of file ptp_doppler.h.

#include <ptp_doppler.h>

Inheritance diagram for satcat5::ptp::DopplerTlv:

Collaboration diagram for satcat5::ptp::DopplerTlv:

Public Member Functions
	DopplerTlv (satcat5::ptp::Client *client)
	Link this instance to a specific PTP client.
void	add_filter (satcat5::ptp::Filter *filter)
	Add to the chain of processing filters. More...
bool	get_tcomp_en () const
	Is timestamp compensation currently enabled?
void	set_tcomp_en (bool enable)
	Enable or disable timestamp compensation. More...
s64	get_velocity () const
	Measured velocity (subns/sec).
s64	get_acceleration () const
	Measured acceleration (subns/sec^2).
bool	tlv_rcvd (const satcat5::ptp::Header &hdr, const satcat5::ptp::TlvHeader &tlv, satcat5::io::LimitedRead &rd) override
	Child class SHOULD override this method to read incoming TLV(s). More...
unsigned	tlv_send (const satcat5::ptp::Header &hdr, satcat5::io::Writeable *wr) override
	Child class SHOULD override this method to append outgoing TLV(s). More...
void	tlv_meas (satcat5::ptp::Measurement &meas) override
	Child class MAY override this method to read or modify each complete two-way handshake event. More...

Protected Attributes
satcat5::ptp::LinearPrediction	m_predict
s64	m_dstamp
satcat5::util::TimeVal	m_tref
bool	m_tcomp
satcat5::ptp::Client *const	m_client
	Pointer to the associated PTP client.

Private Attributes
satcat5::ptp::TlvHandler *	m_next

Member Function Documentation

add_filter()

void satcat5::ptp::DopplerTlv::add_filter ( satcat5::ptp::Filter *  filter )

inline

Add to the chain of processing filters.

Filters are applied in the order added.

Definition at line 35 of file ptp_doppler.h.

set_tcomp_en()

void satcat5::ptp::DopplerTlv::set_tcomp_en ( bool  enable )

inline

Enable or disable timestamp compensation.

(The default setting is given by SATCAT5_DOPPLER_TCOMP.)

Definition at line 44 of file ptp_doppler.h.

tlv_meas()

void DopplerTlv::tlv_meas ( satcat5::ptp::Measurement &  meas )

overridevirtual

Child class MAY override this method to read or modify each complete two-way handshake event.

See discussion above. The default handler takes no action.

Reimplemented from satcat5::ptp::TlvHandler.

Definition at line 114 of file ptp_doppler.cc.

tlv_rcvd()

bool DopplerTlv::tlv_rcvd ( const satcat5::ptp::Header &  hdr, const satcat5::ptp::TlvHeader &  tlv, satcat5::io::LimitedRead &  rd  )

overridevirtual

Child class SHOULD override this method to read incoming TLV(s).

See also

tlv_type.h. For matching type(s), the method should read the TLV contents and return true; otherwise return false. The default handler does not match any incoming TLV.

Reimplemented from satcat5::ptp::TlvHandler.

Definition at line 52 of file ptp_doppler.cc.

tlv_send()

unsigned DopplerTlv::tlv_send ( const satcat5::ptp::Header &  hdr, satcat5::io::Writeable *  wr  )

overridevirtual

Child class SHOULD override this method to append outgoing TLV(s).

The override method MUST predict its output length (input = null). See discussion above. Returns predicted or actual length in bytes. The default handler does not emit any outgoing TLVs.

Reimplemented from satcat5::ptp::TlvHandler.

Definition at line 87 of file ptp_doppler.cc.

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The documentation for this class was generated from the following files:

• ptp_doppler.h
• ptp_doppler.cc