Index: branches/eam_branches/ipp-20220316/fpcamera/src/Makefile.am
===================================================================
--- branches/eam_branches/ipp-20220316/fpcamera/src/Makefile.am	(revision 42225)
+++ branches/eam_branches/ipp-20220316/fpcamera/src/Makefile.am	(revision 42226)
@@ -19,4 +19,5 @@
 	fpcameraLoadRefstars.c      \
 	fpcameraChooseRefstars.c    \
+	fpcameraAstrometryHeaders.c \
 	fpcameraMetadataStats.c     \
 	fpcameraCleanup.c
Index: branches/eam_branches/ipp-20220316/fpcamera/src/fpcamera.h
===================================================================
--- branches/eam_branches/ipp-20220316/fpcamera/src/fpcamera.h	(revision 42225)
+++ branches/eam_branches/ipp-20220316/fpcamera/src/fpcamera.h	(revision 42226)
@@ -72,4 +72,7 @@
 bool 		  fpcameraFPAtoChip (double *xChip, double *yChip, pmFPA *fpa, int nChip, double xFPA, double yFPA);
 
+bool              fpcameraAstrometryFPAHeader(pmFPA *fpa, pmFPAfile *astrom, psMetadata *stats);
+bool              fpcameraAstrometryChipHeader (pmConfig *config, pmFPAview *view, pmReadout *readout, pmFPAfile *astrom);
+
 ///@}
 # endif /* FPCAMERA_H */
Index: branches/eam_branches/ipp-20220316/fpcamera/src/fpcameraAnalysis.c
===================================================================
--- branches/eam_branches/ipp-20220316/fpcamera/src/fpcameraAnalysis.c	(revision 42225)
+++ branches/eam_branches/ipp-20220316/fpcamera/src/fpcameraAnalysis.c	(revision 42226)
@@ -81,4 +81,5 @@
 		    continue;
 		}
+		fpcameraAstrometryChipHeader (config, view, readout, astrom);
 		nChipGood ++;
 	    }
@@ -92,4 +93,5 @@
         if (!pmFPAfileIOChecks (config, view, PM_FPA_AFTER)) ESCAPE(FPCAMERA_ERR_IO, "failure in IOChecks(AFTER) at Chip");
     }
+    fpcameraAstrometryFPAHeader (input->fpa, astrom, stats);
     if (!pmFPAfileIOChecks (config, view, PM_FPA_AFTER)) ESCAPE(FPCAMERA_ERR_IO, "failure in IOChecks(AFTER) at FPA");
 
Index: branches/eam_branches/ipp-20220316/fpcamera/src/fpcameraAstrometryHeaders.c
===================================================================
--- branches/eam_branches/ipp-20220316/fpcamera/src/fpcameraAstrometryHeaders.c	(revision 42226)
+++ branches/eam_branches/ipp-20220316/fpcamera/src/fpcameraAstrometryHeaders.c	(revision 42226)
@@ -0,0 +1,78 @@
+# include "fpcamera.h"
+# define NONLIN_TOL 0.001 /* tolerance in pixels */
+
+bool fpcameraAstrometryBilevel (pmFPAfile *astrom) {
+    myAssert (astrom, "programming error");
+
+    pmFPA *fpa = astrom->fpa;
+    myAssert (fpa, "programming error");
+
+    bool useBilevelWCS = (fpa->toTPA->x->nX > 1) || (fpa->toTPA->x->nY > 1);
+    return useBilevelWCS;
+}
+
+// this is saved on the readout->analysis, but we assume a chip has only one cell & readout
+bool fpcameraAstrometryChipHeader (pmConfig *config, pmFPAview *view, pmReadout *readout, pmFPAfile *astrom) {
+
+    bool status;
+
+    // select the current recipe
+    psMetadata *recipe  = psMetadataLookupPtr (NULL, config->recipes, FPCAMERA_RECIPE);
+
+    // save WCS and analysis metadata in update header
+    // (pull or create local view to entry on readout->analysis)
+    psMetadata *updates = psMetadataLookupMetadata (&status, readout->analysis, "PSASTRO.HEADER");
+    if (!updates) {
+	updates = psMetadataAlloc ();
+	psMetadataAddMetadata (readout->analysis, PS_LIST_TAIL, "PSASTRO.HEADER",  PS_META_REPLACE, "psastro header stats", updates);
+	psFree (updates);
+    }
+
+    bool useBilevelWCS = fpcameraAstrometryBilevel(astrom);
+
+    pmFPA *fpa = astrom->fpa;
+    pmChip *astromChip = pmFPAviewThisChip(view, astrom->fpa);
+
+    // if the toTPA distortion model uses higher-order terms, then we need to use BiLevel astrometry 
+    if (useBilevelWCS) {
+	// create the header keywords to descripe the results
+	if (!pmAstromWriteBilevelChip (updates, astromChip, NONLIN_TOL)) {
+	    psError(PS_ERR_UNKNOWN, false, "invalid solution for %d,%d,%d\n", view->chip, view->cell, view->readout);
+	    psErrorStackPrint(stderr, "failure to generate WCS keywords for one chip\n");
+	    psErrorClear();
+	    return false;
+	}
+    } else {
+	fpa->wcsCDkeys = psMetadataLookupBool(&status, recipe, "PSASTRO.WCS.USECDKEYS");
+	pmAstromWriteWCS (updates, fpa, astromChip, NONLIN_TOL);
+    }
+    
+    return true;
+}
+
+bool fpcameraAstrometryFPAHeader(pmFPA *fpa, pmFPAfile *astrom, psMetadata *stats) {
+
+    bool status;
+
+    bool useBilevelWCS = fpcameraAstrometryBilevel(astrom);
+    if (!useBilevelWCS) return true; // no fpa-level headers if not bilevel
+    
+    // save WCS and analysis metadata in update header.
+    // (pull or create local view to entry on readout->analysis)
+    psMetadata *updates = psMetadataLookupMetadata (&status, fpa->analysis, "PSASTRO.HEADER");
+    if (!updates) {
+        updates = psMetadataAlloc ();
+        psMetadataAddMetadata (fpa->analysis, PS_LIST_TAIL, "PSASTRO.HEADER",  PS_META_REPLACE, "psastro header stats", updates);
+        psFree (updates);
+    }
+
+    if (!pmAstromWriteBilevelMosaic (updates, astrom->fpa, NONLIN_TOL)) {
+	// error here is a data quality problem (and too bad to write smf)
+	psWarning ("Failed to save header terms");
+	if (stats && psMetadataLookupS32(NULL, stats, "QUALITY") == 0) {
+	    psMetadataAddS32(stats, PS_LIST_TAIL, "QUALITY", PS_META_REPLACE, "Mosaic astrometry failed", FPCAMERA_ERR_DATA);
+	}
+	return false;
+    }
+    return true;
+}